Sarah Stephen

21 posts · 7,855 views

The selected few contributors are from, and based in, three different continents (Asia, South America, and Europe) and have worked/studied/lived in four different continents. They have different backgrounds and have been educated in certain universities, in different disciplines, and are currently employed in different facets. Some have engaged/or are current working on research projects concerned with the environment. However, they all are united in their concern for the environment.

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  • April 24, 2012
  • 11:43 AM
  • 72 views

The minefield of diesel emissions

by Sarah Stephen in An ecological oratorio

The carcinogenic effects of diesel emissions/exhaust are widely known. In 1988, the US’ National Institute for Occupational Safety and Health labelled diesel exhaust as potential occupational carcinogen and, in June 2012, the IARC will be revisiting their existing labelling of diesel particulates as potential carcinogens.Particulate Matter (PM) in diesel emission The problematic component of diesel emissions are particulate matter, a topic which yours truly has worked on rather extensively; also, many are the research papers on the morbidity and mortality of PM. PM is an aggregated mixture of salts, inorganic, and organic compounds, generally characterised by aerodynamic diameter. The PM in diesel emissions are collectively very fine (less than 1 μm in diameter) and carbonaceous; but its specific composition depends on the engine characteristics, type of fuel used, and any filtering devices utilised. Effect of PM on human health Nonetheless, the end result is that due to their small size, they can penetrate deeply and cause inflammation. Scientists have analysed PM’s distribution in the human lung and sites with PM deposition were predicted to be future sites of lung cancers. On the whole, short-term effects are usually respiratory related. Long-term effects includes respiratory illnesses (ranging from pulmonary inflammation to allergies), cancer, cardiovascular, and cardiopulmonary disease (for more information/references on all statements: contact me)- and even alternation of gene expression. But many are the studies associating traffic with increased incidences of respiratory and cardiovascular problems. Furthermore, the particle’s surface adsorbs polycyclic aromatic compounds, often with metals and acidic components (some examples being chlorobenzene, quinines, acids, benzo-a-pyrene, mercury, lead, phenols). In fact, is there a need to refer to published research when our old elementary chemistry lessons should suffice in deducing what happens if those compounds enter into our body via our nostrils? (for more information/references: contact me). Diesel exhaust and miners In this backdrop, consider the situation of those working in underground mines. Miners are the occupational group most exposed to high levels of diesel since they use diesel-powered heavy equipment and breathe in the exhaust on a daily basis. Despite the presence of ventilation (if any), in such an enclosed environment, the exhaust level culminates in a very high level. Consequently, researchers at the National Cancer Institute (NCI) and the National Institute for Occupational Safety and Health, via their ‘Diesel Exhaust in Miners Study’, aimed at evaluating the risk of diesel exhaust-associated death in miners, with a sample of 12315 US miners at eight non-metal (to minimise confounding variables such as exposure to carcinogens such as radon, silica, and asbestos) mining facilities (1 limestone mine in Missouri, 3 potash mines in New Mexico, 1 salt mine in Ohio, and 3 trona mines in Wyoming). Four methodology papers were published in the Annals of Occupational Hygiene in 2010. The results were published in March 2012 via two papers. Paper 1 presented the risk of death from any cause (with an emphasis on lung cancer), using data from the full study population (the cohort study). Paper 2, the case-control study, reported the lung cancer deaths in the cohort study, controlling for smoking and other risk factors (such as prior employment in high-risk jobs, history of respiratory diseases, etc). The dose-response results were illuminating and statistically significant, generally illustrating an increasing risk for lung cancer death with increasing levels of diesel exhaust exposure: 1. Those exposed to high levels of diesel exhaust had high three-fold risks of lung cancer (than those exposed to low levels) 2. Those exposed to high levels of diesel exhaust underground faced a five-fold risk. 3. In non-smokers, the risk of lung cancer death increased with increasing exposure to diesel exhaust. Those with the highest level of diesel exposure were 7-times more likely to die from lung cancer than non-smokers in the lowest exposure category. 4. In heavy smokers, the effect of diesel exhaust exposure was attenuated (decreased risk for lung cancer death- decreasing with increasing levels of exposure). It is hypothesised that smoking clears the diesel particulates from the lungs. Furthermore, carcinogens in diesel exhaust and cigarette smoke may operate in the same metabolic pathway in the body and compete with each other, resulting in a saturation of the pathway, thus diminishing the effects of either component (NCI, 2012). Industry’s ireLet’s take a detour and visit the mining industry queen bees in their comfy airconditioned offices, far away from the worker bees in an environment of PM emitting machines. In around 1995, a coalition of mining firms (the Mining Awareness Resource Group) commenced a 17-year legal, legislative, and political battle from conducting and publishing the afore-mentioned epidemiological studies. Their first strategy to stop the study before it began (after all, is there truly any causal link between diesel exposure and lung cancer incidences?). Their next was to control the release of the study findings using quite a many gimmicks such as asking for reviewing the data before publication, holding the researchers in contempt of court for withholding data, and writing vaguely threatening letters to journals which may potentially publish the studies. Potential impactsThe publication of these studies could have the following consequences which affects the industry’s existence and market performance: (rational)investors may withdraw, concerned stakeholders could kick up some troubles, new regulations and standards on diesel emissions, cleaning up, and finding alternatives (all which contributes to compliance costs), and, potentially, miners and their families could sue. Corporate Human Responsibility, anyone? What puzzled me was the effort which the coalition put into preventing the studies from being published. In all probabilities, they deduced that the results would not be conducive to their existing status quo. What certainly doesn’t seem to have been considered by these interested parties (comprising of humans) was the health of their workforce (also comprising of humans). Politicians too seem to have stood with the industry on this matter. Hypothetically, had the study found no correlation, the studies would probably have been well-publicised by the industry. External validityWhilst this study focussed only on the miners, one could extrapolate this to populations/individuals elsewhere exposed to the analysed levels of diesel exhausts. Several countries in the developing world (where emission standards are practically nonexistent) widely use diesel as a vehicle fuel and there is a concentration of usage in trucking, shipping, and rail works. Even if these individuals are not immediately exposed to levels experienced by the underground miners, this could result in a cumulative accumulation. And one needn’t elaborate more on the plight... Read more »

Silverman, D., Samanic, C., Lubin, J., Blair, A., Stewart, P., Vermeulen, R., Coble, J., Rothman, N., Schleiff, P., Travis, W.... (2012) The Diesel Exhaust in Miners Study: A Nested Case-Control Study of Lung Cancer and Diesel Exhaust. JNCI Journal of the National Cancer Institute. DOI: 10.1093/jnci/djs034  

Attfield, M., Schleiff, P., Lubin, J., Blair, A., Stewart, P., Vermeulen, R., Coble, J., & Silverman, D. (2012) The Diesel Exhaust in Miners Study: A Cohort Mortality Study With Emphasis on Lung Cancer. JNCI Journal of the National Cancer Institute. DOI: 10.1093/jnci/djs035  

Stewart, P., Vermeulen, R., Coble, J., Blair, A., Schleiff, P., Lubin, J., Attfield, M., & Silverman, D. (2012) The Diesel Exhaust in Miners Study: V. Evaluation of the Exposure Assessment Methods. Annals of Occupational Hygiene, 56(4), 389-400. DOI: 10.1093/annhyg/mes020  

  • April 10, 2012
  • 02:04 PM
  • 112 views

Controversial, Bt very common

by Sarah Stephen in An ecological oratorio

Probably the most controversial issue in agriculture today is the use of transgenic crops. What does this mean exactly? Well, basically, it is the addition of genetic material from one species into another. Mules, for example, are technically transgenic as they are the offspring of different species, horses and donkeys. The Soviets developed a hybrid of radishes and cabbages, though unfortunately it had the leaves iof radish and the roots of cabbage (*). But what people generally mean these days is the insertion of a particular gene into a plant, which is then expressed in that plant, and it's desecndents.Many transgenic crops include the letters Bt, which comes from Bacillus thuringiensis, a type of bacteria. Now, this bacteria produces a toxin which kills insects, but very very specifically. In other words, it will kill one type of insect, but not another, nor other animals. Put the genes for this toxin in plant cells and they will make it themselves, so that when an insect injests part of the plant, it takes in the toxin.Although there is no reason why virtually any crop should not be engineered to include Bt genes, commercially only two have been, cotton and maize. In 2009 about half the worlds cotton was grown on transgenic plants. It is reckoned that the economic benefit from transgenic cotton globally is about $2.9 billion, 65% from increased yields and 35% from reduced expenditure on pesticides. By far the largest producers are China (3,400,000 hectares) and India (8,400,000 hectares). Bt genes are so specific that there is a growing trend to combine several in each plant, to defend against a cocktail of pests.Of course people don´t eat cotton, whilst they do maize. Nonetheless, 16 countries around the world grow transgenic maize against 11 growing cotton, with the USA (over 17 million hectares) and Brazil (5 million ) being the largest growers. In this case, genes have sometimes been combined with those for drought resistance, allowing maize to grow where iin the past it struggled.One of the reasons for the controversy over GM technology is the control companies such as Monsanto exert over their products. Of course any plant breeder needs to protect their investment, but the huge development costs involved here mean that not only are GM seeds normally more expensive, but the legal protection is much more stringently applied - think DRM in software. That's all very well, but once a plant is in a distant valley, it's quite hard to monitor. For example, it has been reckoned that about 60% of cotton grown in the Indian state of Gujarat in 2007 was illegal. With the best will in the world, the fate of seeds after harvest is not necessarily enforecable, and there are plenty of people willing to grow seeds for sale. Storing your own crop or buying from local producers are both traditional sources of seeds and it is hard to convince people that this is, or should be, illegal.So, is it safe?A recent paper (**from which some of the figures above were also culled) surveys the many papers published on this subject. It has to be said that the author tends to dismiss negative studies as either badly designed or otherwise inadequate, but anyway his conclusions are as follows.Firstly, and most importantly, there is no evidence of any toxicity at all to mammals such as ourselves.The advantage of Bt proteins is their specificity, and even insect predator species tested don't seem to suffer any ill effects from eating poisoned prey, but parasitoids do. These are species that parasitise pests, and though they do not suffer themselves from the toxins, weaker hosts mean fewer parasitoids. As they can be important in controlling pest populations this is something to bear in mind.A major concern in the early days was a possible effect on honey bees, feeding on the pollen and nectar of transgenic plants. This of course would impact on growers of other crops, not getting any benefit from the transgenics themselves. Fortunately as yet there is no evidence of toxicity on honey bees, or on the butterflies tested, which might be expected as they are more related to the pests targeted.Of course, as ever in life, there are unintended consequences. For one thing, insects are quite capable of evolving resistance to Bt proteins. It is not common, and there are ways to limit it, but Bt toxins are not foolproof. And secondly, if Bt is killing your most annoying pest you can apply less pesticide, which means other pests can fill the gap. Here the specificity of Bt is actually a handicap. Species as diverse as aphids, leaf hoppers, spider mites and thrips have all emerged to threaten the new crops, which can lead to increased insecticide use, which defeats the whole point of Bt crops. Fortunately, generally they are less severe than the original enemies, and higher levels of insect predators, not affected by Bt, help keep them under control.*Karpechenko GD. Polyploid hybrids of Raphanus sativus L. X Brassica oleracea. L Bull Appl Bot. 1927;17:305–410.**Transgenic Crops: An Option for Future Agriculture. Wei-Cai Yang and Jianmin Wan. Journal of Integrative Plant Biology. July 2011. Volume 53, Issue 7. Pages 510–595Karpechenko GD (1927). Polyploid hybrids of Raphanus sativus L. X Brassica oleracea L Bull Appl Bot, 17, 305-410Yang, W., & Wan, J. (2011). Transgenic Crops: An Option for Future Agriculture Journal of Integrative Plant Biology, 53 (7), 510-511 DOI: 10.1111/j.1744-7909.2011.01064.x... Read more »

Karpechenko GD. (1927) Polyploid hybrids of Raphanus sativus L. X Brassica oleracea. L Bull Appl Bot, 305-410. info:other/

Yang, W., & Wan, J. (2011) Transgenic Crops: An Option for Future Agriculture. Journal of Integrative Plant Biology, 53(7), 510-511. DOI: 10.1111/j.1744-7909.2011.01064.x  

  • February 27, 2012
  • 03:09 AM
  • 194 views

In pursuit of a fox

by Sarah Stephen in An ecological oratorio

"The English country gentleman galloping after a fox - the unspeakable in full pursuit of the uneatable."- Oscar Wilde in A Woman of No Importance.An overcast Boxing Day in a quintessentially English village/town in South Gloucestershire. The place is typically peaceful, although not so that morning. In fact, it looked like a scene from John Constable’s paintings: an excited throng at the village centre; huntsmen and women on their powerful hunters and invigorated hounds prancing at the sound of the bugle; the bystanders cheering wildly with much fervour- setting off towards the rolling countryside is a typical fox hunt. The fox hunt might sound strange to the non-British. It is commonly viewed as a traditional English sport, integral to a country life, complete with high expenses and pomp. Packs of trained hounds pick up the scent of the red fox (Vulpes vulpes) and chases it across the countryside (there being no geographical limitations), followed by riders on hunters. One can easily picture the damage caused by the galloping of horses on fences and hedges on the way and agricultural fields. However, since fox hunting is technically banned in the UK via the Hunting Act 2004 (enforced since February 2005, much to the dismay of the supporters), the hounds now supposedly follow the trail of an artificial scent (an errant fox in their path is considered as an accident). Anti-hunt groups still maintain that fox hunting is rife- after all, no one can keep up with the chase (unless they masquerade as huntsmen) and some have boasted along the lines of getting around the law. Hunt supporters view fox hunting (or any other seasonal hunting) as neither cruel nor wrong. The supporting arguments are many: an important rural English tradition, conservation, and purging nature by eliminating diseased/old/injured/young foxes. A study, which sits on the fence, states that in the event of a fox-hunting ban, there would be no detectable population increase as the number of foxes killed by hunting is relatively small. Furthermore, foxes (which are considered vermin- along with squirrels and rats) haven’t exactly been making themselves endearing- for instance, they indulge in an incomprehensible carnage in hen coops even though all they need is only one hen. As a control measure, hunting is presented as a humane option (when compared to poisoning/shooting/snaring- which entails greater suffering, with other animals as inopportune victims) - whilst the chase itself is said to take just under an hour, foxes are killed (supposedly instantaneously) after a chase averaging 17 minutes. Opponents of the hunt (a list which includes luminaries such as Thomas More, Oliver Cromwell, and Dr Samuel Johnson) finds it nonsensical, cruel, and unnecessary- a sport which transforms the huntsmen into beasts, sans any semblance of human virtues. Fox-hunting has no significant reduction in the fox population and doesn’t provide any sustenance. The only gain (and for those so inclined) is obtaining pleasure from witnessing such unnecessary suffering. One criticism is that the sport is limited to and glorifies the lifestyle of the rarefied strata of society and supporters of a certain political party (admittedly, a glance at my acquaintances who keep hounds supports that statement). So here it is- an exclusive sport, a mixture of violence and sentimentality for olden traditions, transporting one back into feudal times. Any thoughts?References/Sources:Newall, V. (1983). The Unspeakable in Pursuit of the Uneatable: Some Comments on Fox-Hunting Folklore, 94 (1), 86-90 DOI: 10.1080/0015587X.1983.9716259FRANKLIN, A. (1996). On Fox-hunting and Angling: Norbert Elias and the 'Sportisation' Process Journal of Historical Sociology, 9 (4), 432-456 DOI: 10.1111/j.1467-6443.1996.tb00106.xGunn, A. (2001). ENVIRONMENTAL ETHICS AND TROPHY HUNTING Ethics & the Environment, 6 (1), 68-95 DOI: 10.2979/ETE.2001.6.1.68Baker PJ, Harris S, & Webbon CC (2002). Effect of British hunting ban on fox numbers. Nature, 419 (6902) PMID: 12214224Baker, PJ., Harris, S., Webbon, CC (2002). Response to Aebischer, NJ, Baker, SE, Johnson, PJ, Macdonald, DW, and Reynolds, JC. Nature, 423, pg. 400Anderson, A. (2006). Spinning the Rural Agenda: The Countryside Alliance, Fox Hunting and Social Policy Social Policy and Administration, 40 (6), 722-738 DOI: 10.1111/j.1467-9515.2006.00529.xhttp://www.telegraph.co.uk/earth/countryside/8872182/Why-fox-hunting-is-more-popular-than-ever.htmlhttp://www.telegraph.co.uk/earth/wildlife/8977417/David-Cameron-to-ditch-foxhunting-U-turn.htmlhttp://www.guardian.co.uk/uk/2011/dec/26/fox-hunting-ban-call-repeal... Read more »

Newall, V. (1983) The Unspeakable in Pursuit of the Uneatable: Some Comments on Fox-Hunting. Folklore, 94(1), 86-90. DOI: 10.1080/0015587X.1983.9716259  

FRANKLIN, A. (1996) On Fox-hunting and Angling: Norbert Elias and the 'Sportisation' Process. Journal of Historical Sociology, 9(4), 432-456. DOI: 10.1111/j.1467-6443.1996.tb00106.x  

Gunn, A. (2001) ENVIRONMENTAL ETHICS AND TROPHY HUNTING. Ethics , 6(1), 68-95. DOI: 10.2979/ETE.2001.6.1.68  

Baker PJ, Harris S, & Webbon CC. (2002) Effect of British hunting ban on fox numbers. Nature, 419(6902), 34. PMID: 12214224  

Anderson, A. (2006) Spinning the Rural Agenda: The Countryside Alliance, Fox Hunting and Social Policy. Social Policy and Administration, 40(6), 722-738. DOI: 10.1111/j.1467-9515.2006.00529.x  

  • October 9, 2011
  • 07:17 PM
  • 259 views

A matter of the heart

by Sarah Stephen in An ecological oratorio

Some years ago, I accompanied a young relative, a very eager science graduate working on particulate matter, as she conducted her research survey on public perception of particulate matter and its effects in a certain borough of London Particulate matter (PM) is used to describe solid matter suspended in a gas or liquid phase. In the environment, particulates may occur naturally (as consequence of forest fires, volcanoes, dust storm, sea sprays etc) or via anthropogenic activities, such as the burning of fossil fuels in automobile exhausts and other industrial processes. PM10 is used to describe particles of 10 micrometres or less. Unsurprisingly, densely populated metropolitan areas in developing countries are hot spots for PM. The exercise with my relative was an eye-opener, and also quite fun as we pounced on shoppers, city workers on lunch breaks, pedestrians in Central London etc., armed with our clip boards and ticking or crossing their responses. I enjoyed being the magician’s assistant….but that is another story.All this came back to me as I read the recent article by Bhaskaran et al, of the London School of Tropical Medicine and Hygiene, who studied the effects of air pollution on the risk of heart attack- specifically whether alterations in pollution levels on an hourly timescale affects the short-term risk in urban settings of England and Wales, So what is the novelity in this study? The links between particular matter and heart and lung diseases is documented and there are several publications in these topics.In an earlier post in this site, David discussed a study where PM10 caused increase in blood pressure in traffic controllers in the metropolitan area of Sao Paolo. However, there is a wee difference in what this paper covered: this work considered the overall risk of heart attack in urban settings of England and Wales over very short time frames and it involved a large population siz. In essence, this study looked at effects of very short-term exposure (which was not, previously, possible to model due to technology limitations). In this mega-study of over 79000 individuals with a diagnosis of heart attack over three years from 15 cities( including Greater London, Greater Manchester, West Yorkshire, Bristol, Cardiff, Southampton) the team looked at PM10 and other pollutants such as ozone, carbon monoxide, nitrogen dioxide, and sulphur dioxide over five short periods of up to 72 hours. For the analysis of their results they used statistical modelling approach for single pollutant and multiple pollutants where they adjusted for factors that could influence and otherwise confuse data including ambient temperature, humidity, virus in the atmosphere ( both that for flu and for respiratory syncytial virus). The researchers found that increase in PM10 levels & NO2 levels was associated increase in risk for heart attacks 1-6 hours post-exposure;.The source of PM10 & NO2 in urban areas is largely from automobile exhausts. Interestingly the increase in immediate risks was followed by reduction in risks at longer lags and therefore they found no net risk increase over 72 hour periods. They found a protective effect for increase in CO & ozone however; there was no change in overall risk over 72 hours leading the team to speculate that ischaemic events that would have occurred soon were advanced by a few hours. Most studies so far had shown the effects after years of chronic exposure and herein lies the difference of this study. A previous small study in Greater Boston with less than 1000 subjects showed an increased risk 1-3 hours after exposure of PM10. The risk was 11% which is higher than that observed in the current studyWhat do the results mean cumulatively? Remember this was a statistical exercise, though a worthy one. It would still be interesting to explore the physiological, cellular, & molecular basis of organ responses to short-term exposure to PM10 which will further our understanding. It might also be interesting to pursue questions such as, are there individuals of a particular genetic signature who might be prone to the effects of short-term exposure and low doses of PM more than others? the effect of age etc. Are similar trends seen in respiratory disorders? Does PM exposure compound the effects in vulnerable populations? All these questions remain.But what does the study mean to the society as a whole and what can we do? The results in addition to the existing body of evidence should send warning bells to the world but emerging economies that are mushrooming urban sprawls. The recent UN summit highlighted the importance of non-communicable diseases including cardiovascular disease on the global health. With NCDS (CVDS and cancer) accounting to 36 million of global deaths in 2008 WHO stats, the UN draft resolutionon (dated 16 September 2011) submitted by the President of the General Assembly - political declaration of the high level meeting of the general assembly on the prevention and control of non-communicable diseases -concedes the gravity of the situation and ‘recognizes that prevention must be the cornerstone of the global response to NCDS’ and identified several modifiable factors including diet and tobacco smoke that results in the rise of NCDS and called for ‘reducing their exposures’. These are valid and commendable. However, a glaring omission is the lack of mention of air pollutants contributing to NCDs. In the UN document, the closest air pollution is touched is the reference g to the pollution from cooking stoves for indoor cooking and heating. In essence, the enumerated risk factors do not include particulate matter from vehicles!!.The results in this paper and the other background research cannot be ignored and should prompt usto push for measures for cutting down particulate matter emissions. Prevention is certainly a better option than treatment and cure as the UN draft declaration as well as common sense dictate. Importantly, prevention is something that is easy to achieve, but requires efforts starting from the individual to local to the global.http://ecoratorio.blogspot.com/2011/08/stuck-in-traffic.htmlhttp://www.ghd-net.org/negotiations/un-summit-non-communicable-diseases/official-documentsBhaskaran K, Hajat S, Armstrong B, Haines A, Herrett E, Wilkinson P, & Smeeth L (2011). The effects of hourly differences in air pollution on the risk of myocardial infarction: case crossover analysis of the MINAP database. BMJ (Clinical research ed.), 343 PMID: 21933824... Read more »

Bhaskaran K, Hajat S, Armstrong B, Haines A, Herrett E, Wilkinson P, & Smeeth L. (2011) The effects of hourly differences in air pollution on the risk of myocardial infarction: case crossover analysis of the MINAP database. BMJ (Clinical research ed.). PMID: 21933824  

  • September 11, 2011
  • 05:26 PM
  • 577 views

Marine mammals and their future

by Sarah Stephen in An ecological oratorio

Marine mammals have borne the brunt of mankind’s unsustainable overexploitation, resulting in population decline and species extinction. Hunting for fur, blubber, and meat in the 19th and 20th centuries resulted in the extinction of three species – the Caribbean monk seal (Monachus tropicalis), Atlantic gray whale (Eschrichtius robustus), and the Steller’s sea cow (Hydrodamalis gigas). The most recent extinction, due to its use in traditional medicine, was that of the Baiji (Lipotes vexillifer) in 2008, a dolphin endemic to the Yangtze River.In this backdrop, the August 16th edition of PNAS featured an excellent research (it truly is wonderful to come across such), entitled ‘Global distribution and conservation of marine mammals’, by Sandra Pompa and Gerardo Ceballos (National Autonomous University of Mexico) and Paul Ehrlich (Stanford). The mammalian species considered in the study were 129 in total (123 marine and 6 freshwater species), grouped into the orders of Cetacea, Sirenia, and Carnivora (common examples being whales, dolphins, porpoises, otters, seals, and polar bears) .Method The researchers created geographic range maps for the 129 species and the map of the water bodies were split into grids of roughly 10,000 km2. They determined the number of species in each grid cell and calculated the total number of cells occupied by each species. Breeding, calving, and feeding grounds, and migratory routes were also factored in. The result was a composite global distribution map of water bodies, revealing locations of ‘global species richness, irreplaceable sites, endemism, and threatened species.'Results1. All species can be represented in 20 global key conservation sites that cover at least 10% of the species' geographic range. These sites were determined on the basis: number of species present (species richness), severity of the risk of extinction for each species, and whether the species was endemic to the area.2. Preserving 9 of such sites (mostly in temperate latitudes located off the coasts of Baja California in Mexico, the Atlantic coast of North America, Peru, Argentina, north-western Africa, South Africa, Japan, Australia, and New Zealand) would protect the habitat of 83.72% (108/129) of marine mammal species (including 5 endemic species) since these have high species richness.3. The remaining 11 sites (6 freshwater, 5 marine: areas around Hawaiian and Galapagos Islands, Kerguelen Islands in the southern Indian Ocean, San Felix and Juan Fernandez Islands off the coast of Chile, Mediterranean Sea, Lake Baikal in Siberia, Caspian Sea, and major rivers such as the Amazon, Ganges, Indus, and Yang-tze) were tagged ‘irreplaceable key conservation sites’ of great conservation value due to the presence of endemic species, which, consequently, face a greater risk of extinction.Eg. Galapagos fur seal (A. galapagoensis) and the Mediterranean monk seal (Monachus monachus).4. Strong correlation of marine mammal species richness with human impacts (Spearman rank correlation (rs = 0.693, n = 46,164, P < 0.01 for climate disruption; rs = 0.666, n = 46,164, P < 0.01 for pollution; and rs =0.678, n = 46,164, P < 0.01 for shipping). The existing deterioration of the marine ecosystems due to anthropogenic activities (and the potential for more deterioration not just at these sites but also elsewhere) was evidenced by around 70% percent of most impacted areas being within or near key conservation areas. Factoring in other impacts such as commercial fishing would result in stronger correlation (and perhaps also global climate change, habitat degradation, ocean acidification, exploitation of natural resources such as oil and gas, hunting, tourism, and plastics?)5. 10% of all marine mammals were considered to be vulnerable, 11% endangered, and 3% critically endangered. The following vulnerable species were identified:i. Vaquita (a porpoise species), endemic to the Gulf of Baja California, has the most restricted range. Its population has been declining rapidly and there are only 150-300 individuals in the wild (1/5 of the population are killed in gillnets each year).ii. Sea lions such as the endemic Australian sea lion (Neophoca cinerea) and the Galapagos sea lion (Zalophus wollebaeki), and the restricted range New Zealand sea lion (Phocarctos hookeri).iii. Seals such as the freshwater and endemic Baikal seal (Pusa sibirica), and the endemic Galapagos fur seal (Arctocephalus galapagoensis) and Hawaiian monk seal (Monachus schauinslandi).iv. Whales at the brink of extinction, such as North Atlantic right whale (Eubalaena glacialis) and Sei whale (Balaenoptera borealis), due to overharvesting, pollution, bycatch, and exhaustion of prey-species populations.v. Dolphins such as the endemic New Zealand dolphin (Cephalorhynchus hectori) and the restricted range Australian Snubfin dolphin (Orcaella heinsohni).Implications This research could be a useful tool for environmental organisations and governments in identifying conservation areas and anthropogenic threats so as to protect endangered marine mammals and keep the oceans’ ecosystem functional. Mammals hold a lofty position in the food chain- consequently, their population dynamics would affect all other components of an ecosystem (and in human communities, by extension).Pompa S, Ehrlich PR, & Ceballos G (2011). Global distribution and conservation of marine mammals. Proceedings of the National Academy of Sciences of the United States of America, 108 (33), 13600-5 PMID: 21808012And the must read: http://www.pnas.org/content/suppl/2011/07/27/1101525108.DCSupplemental/sapp.pdfImage source: Apollo 17... Read more »

Pompa S, Ehrlich PR, & Ceballos G. (2011) Global distribution and conservation of marine mammals. Proceedings of the National Academy of Sciences of the United States of America, 108(33), 13600-5. PMID: 21808012  

  • August 28, 2011
  • 08:27 AM
  • 737 views

Mr Wolf, I presume?

by Sarah Stephen in An ecological oratorio

Those of us who have a long-standing interest in Egyptian mythology would remember Anubis, the jackal-headed god of the dead, who held the unappealing portfolio of funerals, afterlife, mummification, fate of souls, and protection of the dead and their tombs. This was presumably because Anubis’ animal counterpart, the Egyptian Jackal (Canis aureus lupaster; Hemprich and Ehrenberg, 1833), preferred to occupy burial grounds. C.a.lupaster was considered to be a large, rare subspecies of the golden jackal (Canis aureus; Linn. 1758) even though there has been a historic (ahem) bone of contention over whether it is a jackal or a wolf (given its wolf-like morphology). Ancient Greeks considered these to be smaller versions of the European wolves; evolutionary biologist Thomas Huxley, after comparing the skulls of C.a. lupaster and Indian wolves, considered the species as grey wolf; Walter Ferguson (1981) argued that it was a species of wolf after studying its cranial measurements.

But research published earlier this year by collaborators from Oxford University's Wildlife Conservation Research Unit (WildCRU), University of Oslo, and Addis Ababa University has established the Egyptian jackal’s true skin. When the mitochondrial DNA of the Egyptian jackal was compared with that of the golden jackal, wolves, and wolf-like canids, the results demonstrated that the Egyptian jackal (whether in Egypt or Ethipia) is (and should be renamed as) an African Wolf, a subspecies of grey wolf or a separate species in itself, which existed alongside the golden jackals and the rare Ethiopian wolf (Canis simensis, an unique but endangered species). Furthermore, sequencing of mtDNA from Ethiopian highland golden jackals revealed that these were, in fact, Egyptian jackals (i.e. the African Wolf). African wolves are closely related to the Indian (Canis lupus pallipes) and Himalayan wolves (Canis lupus chanco- with 2.4% divergence).
What does this bode for the species? The authors of the PLoS study called for assessing the status of the African wolf. Its previous classification as a subspecies of golden jackals meant being listed as a species of least concern by the IUCN. But since this is now the only grey wolf species in Africa, this could be rare and endangered.
... Read more »

Rueness EK, Asmyhr MG, Sillero-Zubiri C, Macdonald DW, Bekele A, Atickem A, & Stenseth NC. (2011) The cryptic African wolf: Canis aureus lupaster is not a golden jackal and is not endemic to Egypt. PloS one, 6(1). PMID: 21298107  

  • August 23, 2011
  • 12:29 PM
  • 552 views

More scientific grub on migration

by Sarah Stephen in An ecological oratorio



A previous post presented how those characteristic summer chorus of the English countryside may be soon an event of the past. This rapid decrease in the population of migratory birds in the UK was attributed to habitat destruction and other such anthropogenic factors, probably somewhere along the migration corridor. So what does habitat destruction and other anthropogenic influences bode for migrating organisms? Vishwesha Guttal and Iain Couzin, of Princeton University, try to predict this (amongst other interesting stuffs) via models explained in their paper on ‘Social interactions, information use, and the evolution of collective migration’, an interesting read, although a tad too technical for the layman.

Organisms, all along the phyla of the animal kingdom, are believed to migrate as a result of detecting and responding to factors governing resource availability. The foundational theory considers each migrating individual as “‘information processing units’, with interactions amongst them providing collective benefits”, such as improved migratory direction. Should an individual commit an error in the information processing, the aforementioned grouping would average the individual measurements, so as to deduce the mean migratory direction.

These migrating populations have two types of individuals:


-Leaders, who have a higher ability to detect and respond to directional gradient from the environment, but with weak (or none) social skills. They tend to occupy frontal or peripheral positions and expend more energy in trotting off the beaten track and facing dangers such as predators.
-Social individuals, who have strong social skills but weak ability to detect and respond to gradient. However, they utilise the strengths of the leaders for a free ride.

Population density, according to the model, is a crucial leverage factor. Extremely low-density populations (ergo, lesser probability of encountering others) comprises of leaders, thus resulting in solitary migration. Extremely high-density populations results in resident population due to a lack of migration (attributed to frequent ‘collisions among individuals’). It is when leaders and social individuals coexist that collective migration ensues. The bottom-line is that ‘the evolution of the migratory strategy (resident, solitary, or collective) is determined by the ecology of the species (i.e population density, habitat structure, costs and benefits of migration)’. Presumably, there could be other regressors as well....

Anthropogenic factors have been exerting pressures (such as habitat fragmentation and changes in population density) on the existence of many migratory species (examples cited in the paper includes: American bison and its steep decline in its population density; extinction of passenger pigeon) and migratory patterns (Blackcaps becoming resident; Eastern house finch exhibiting the reappearance of lost migration). As habitat fragmentation increased, the individuals adapt their migratory strategy by travelling longer distances to find an appropriate habitat. The researchers’ model predicted that in such cases, paradoxically, the population’s migration ability reduces relatively gradually with increasing habitat fragmentation. The reasoning is that: ‘at high levels of habitat fragmentation, no individuals evolve to be leaders, and therefore, the population loses its migratory ability. Even after restoring the habitat, a population’s migratory ability does not recover at the same habitat quality at which it declined due to the relatively short time scale of these changes’.

Guttal V, & Couzin ID (2010). Social interactions, information use, and the evolution of collective migration. Proceedings of the National Academy of Sciences of the United States of America, 107 (37), 16172-7 PMID: 20713700


Image Source: The Wandering Angel
... Read more »

Guttal V, & Couzin ID. (2010) Social interactions, information use, and the evolution of collective migration. Proceedings of the National Academy of Sciences of the United States of America, 107(37), 16172-7. PMID: 20713700  

  • August 9, 2011
  • 07:06 PM
  • 369 views

Stuck in traffic

by Sarah Stephen in An ecological oratorio


As you sit in the rush hour queues, pity the poor guy or girl directing the traffic, and imagine the fumes they are breathing in. In Brazil, with rapidly expanding car ownership, but not necessarily expanding road space, this is an increasing problem.

A recent study* in the city of Santo Andre, part of the metropolitan region of Sao Paulo, focused on traffic controllers. The study focused on male, non smoking, traffic controllers who had been exposed for over 3 years. As the authors note, one criticism of the study is that it might actually underestimate health concerns, as unhealthy controllers were excluded from the test group to achieve homogeneity. Thus the subjects might be constitutively more able to adapt to air pollution, or just have healthier working practices.

The study concentrated on particles in the air (from dust, car exhaust etc) and ozone. The level of particulate matter has fallen in recent years, below the official limits of 50 and 25 ug/m3 for PM10 and PM2.5 respectively (PM 10 and 2.5 are different particle sizes), but that is still considered hazardous by many observers. Road dust accounts for about 30% of air pollution and is mainly composed of PM 10 particles, so the authors concentrated on this size in particular. Furthermore ozone levels are increasing, especially at times of high temperatures and low humidity. High ozone has been associated with cardiovascular disease.

They found that both PM10 particulates and ozone were associated with increased blood pressure, but in different ways. PM10 pollution caused a blood pressure rise almost immediately, which still remained 4 hours later, whilst the effect of ozone delayed for 2 hours of exposure, but was still apparent 5 hours later.

So, the traffic controllers are suffering measurable cardiovascular effects every day, continuing even when the pollution is removed, and in quite a stressful job. It might not end there. The so called "interior diesel" used in some cities such as Santo Andre has a lot more sulphur than the diesel distributed in the main cities (1,200 vs 500 ppm), which has been shown to cause endothelial disfunction, oxidative stress, and probably long term hypertension.

It's a dangerous job, standing in the middle of traffic, in more ways than one.

Sérgio Chiarelli P, Amador Pereira LA, Nascimento Saldiva PH, Ferreira Filho C, Bueno Garcia ML, Ferreira Braga AL, & Conceição Martins L (2011). The association between air pollution and blood pressure in traffic controllers in Santo André, São Paulo, Brazil. Environmental research, 111 (5), 650-5 PMID: 21570068

*P.S. Chiarellietal et al 2011. The association between air pollution and blood pressure in traffic controllers in SantoAndre, Sao Paulo, Brazil Environmental Research 111 650–655

... Read more »

Sérgio Chiarelli P, Amador Pereira LA, Nascimento Saldiva PH, Ferreira Filho C, Bueno Garcia ML, Ferreira Braga AL, & Conceição Martins L. (2011) The association between air pollution and blood pressure in traffic controllers in Santo André, São Paulo, Brazil. Environmental research, 111(5), 650-5. PMID: 21570068  

  • June 27, 2011
  • 03:43 PM
  • 393 views

Yellow gold : Turmeric and its promise

by Sarah Stephen in An ecological oratorio

Growing up in Southern India, we cultivated several vegetables and spices in our backyard, one of which was turmeric. Turmeric (Curcuma longa) belongs to the same family as ginger. It is rhizomatous herb and normally pieces of the rhizome are planted in the rainy months of July. In our hands, the plants did not require much care at all. No artificial fertilizers were used nor wwere the plants watered but only left to the mercy of nature. But our part of South India is blessed with rains anyway, at least then, before the global warming and stuff but that’s another story. The rhizomes were harvested in the following summer. One signal that it was time for harvest was the death of the leaves. Once this occurred, the root tubers were all plucked out from the soil. This often coincided with the latter half of the summer vacations and was a joyous occasion for us when we were children. The tubers were then washed in water to remove the soil. By the time the mud was washed off our little palms would all be yellow. Imagine our delight when our hands turned read when we tried to wash it away with soap (Turmeric is a PH indicator turning from yellow to red in alkaline conditions). The tubers were then sun dried and pulverized to be used for culinary purposes. Turmeric occupies a lofty place in Indian culture, well almost like gold. In fact nearly most of South Indian dishes use it as a seasoning. In Ayurveda, it is associated with a manifold health benefits. Apart from using turmeric powder to spice dishes, the fresh root tubers are ground and used as masques on the skin which issupposed to prevented sun induced damage and blemishes. It also plays an important role in auspicious ceremonies like weddings. In many sections of the Indian society the prospective bride and bridegroom have ritual baths with turmeric due to its edifying propertiesFor the last decade or so, turmeric has moved from the spice cupboards in Indian kitchens to the laboratory benches where researchers are investigating the overwhelming evidence of its' beneficial effects. It is estimated that turmeric has about 100 constituents. 5% of the rhizome comprises of essential oils and 5% curcumin, the latter is the best studied active substance. Curcumin is identified as responsible for most of the biological effects of turmeric although whether turmeric as a whole or curcumin is isolation is most effective is debated. Some believe that turmeric as a whole is superior than curcumin for some conditions (http://www.drweil.com/drw/u/QAA400915/Curcumin-or-Turmeric.html). Indeed, most research activity has centred around curcumin in isolation. Imagine the complexity if the labs were to investigate the individual compounds that make up turmeric. Turmeric can rightly be called ‘ the mother of all spices’ . In fact evidence indicates that it is anti inflammatory, anti carcinogenic and anti diabetic to name a few of its health benefits. How turmeric exerts is manifold benefits is only starting to unravel as several labs around the world are investigating the molecular mechanisms of curcumin. Limited evidence suggests that turmeric and its active compound, curcumin, are effective for rheumatoid arthritis and other inflammatory diseases such as psoriasis, inflammatory bowel disease (IBS), inflammatory eye disease and familial adenomatous polyposis. Other inflammatory diseases where turmeric might play an important role are neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, multiple sclerosis. Indeed these diseases are less common among people living in the Asian subcontinent, where people regularly consume spices. More in a futue postCheck these links that review therapeutic roles curcumin Howes MJ, Perry E. The role of phytochemicals in the treatment and prevention of dementia.World J Gastrointest Pathophysiol. 2011 Feb 15;2(1):1-14. Rajasekaran SA. Therapeutic potential of curcumin in gastrointestinal diseases. Drugs Aging. 2011 Jun 1;28(6):439-68.Wilken R, Veena MS, Wang MB. Curcumin: A review of anti-cancer properties and therapeutic activity in head and neck squamous cell carcinoma. Mol Cancer. 2011 Feb 7;10:12.Park J, Conteas CN. Anti-carcinogenic properties of curcumin on colorectal cancer. World J Gastrointest Oncol. 2010 Apr 15;2(4):169-76.Pocernich CB, Bader Lange ML, Sultana R, Butterfield DA. Nutritional Approaches to Modulate Oxidative Stress in Alzheimer's Disease. Curr Alzheimer Res. 2011 May 23. Huang J, Plass C, Gerhäuser C. Cancer Chemoprevention by Targeting the Epigenome. Curr Drug Targets. 2010 Dec 15.... Read more »

Howes MJ, & Perry E. (2011) The role of phytochemicals in the treatment and prevention of dementia. Drugs , 28(6), 439-68. PMID: 21639405  

Rajasekaran SA. (2011) Therapeutic potential of curcumin in gastrointestinal diseases. World journal of gastrointestinal pathophysiology, 2(1), 1-14. PMID: 21607160  

Wilken R, Veena MS, Wang MB, & Srivatsan ES. (2011) Curcumin: A review of anti-cancer properties and therapeutic activity in head and neck squamous cell carcinoma. Molecular cancer, 12. PMID: 21299897  

Park J, & Conteas CN. (2010) Anti-carcinogenic properties of curcumin on colorectal cancer. World journal of gastrointestinal oncology, 2(4), 169-76. PMID: 21160593  

Pocernich CB, Bader Lange ML, Sultana R, & Butterfield DA. (2011) Nutritional Approaches to Modulate Oxidative Stress in Alzheimer's Disease. Current Alzheimer research. PMID: 21605052  

Huang J, Plass C, & Gerhäuser C. (2010) Cancer Chemoprevention by Targeting the Epigenome. Current drug targets. PMID: 21158707  

  • June 11, 2011
  • 11:25 AM
  • 340 views

Dams on the Xingu

by Sarah Stephen in An ecological oratorio

On June 1st Dilma Rousseff, the President of Brazil, controversially gave permission for the company Norte Energia to begin building a hydroelectric dam on the Xingu river in the northern state of Para. This follows the granting of a provisional licence in January by the previous president, Lula da Silva, to begin land clearance and road construction, and years of court cases. A total of eleven cases have been filed against the project by the Federal Public Prosecutor, over various irregularities, the last being overturned in February.Artists impression of the damThe Belo Monte dam complex will in fact consist of 3 dams. The first, Pimental Dam, will be 36 metres tall, over 6 kilometres long, and will create a lake with a surface area of 129 square miles. This will supply one power station. Two canals will channel water down to another reservoir created by the Belo Monte dam, which will supply another power plant. The Belo Monte dam will be 90 metres tall but only 3.5 kilometres wide, and create a lake of 42 square miles. The whole complex is expected to cost 16 billion US$, with power cables costing a further US$ 2 billion.For good or ill this is going to affect a lot of people.AdvantagesOn the positive side, an immense amount of energy will be generated, the Belo Monte dam is the third largest hydroelectric project in the world after the Three Gorges Dam in China and the Itaipu dam between Brazil and Paraguay. Itaipu already supplies 19% of Brazil's energy needs and virtually all of Paraguay's. The planned capacity of Belo Monte is unclear, as we will see below, but it is claimed by EletroBras, the state electricity company to at least supply the state of Para (population 7.5 million). This of course is all power that would otherwise have to generated by fossil fuels or nuclear energy. Once built, the running costs will be minimal, and electricity will be provided continuously (well, again, see below) for over 50 years. It's not true that will be no carbon emissions. Studies of other Brazilian dams have found that as the water level falls and rises every year, vegetation flourishes in the tropical climate, only to be submerged and decay, releasing methane. But the amount is probably much less than an equivalent coal fired power station.The location, with a natural drop in elevation, allows the use of a relatively low wall, and thus smaller reservoir, to generate power requiring a much bigger reservoir elsewhere. Thus, the argument goes, if you are going to have a dam, this is the place to have it.Aluminium at BarcarenaApproximately 18,000 jobs will be created by the construction project, and another 25,000 indirectly, although of course most of these will cease when construction is finished. More long term will be aluminium processing plants powered by the dam, with a view to export to China. The planned Brazilian-Chinese bauxite processing plant at Barcarena, Para, will be the largest in the world. There are also existing Japanese and American plants which will be expanded. This gives Brazil a much higher value export product than simple ore.DisadvantagesThe disadvantages can be divided into social, practical and environmental.SocialFor a start over 20,000 people will be directly displaced. These people will need to be resettled. Then there are the people downstream, mainly from the Juruna and Arara tribes. As they will not be directly affected they have not been offered resettlement, but as the river is a major food supply and transport network, falling levels will possibly cause displacement anyway. This will probably be exasapated by increased levels of water borne diseases from more stagnant pools. In fact, the vast majority affected by this project will be indigenous peoples, and this has aroused a lot of resentment, and threats of violence.In contrast, an estimated 100,000 migrants from other parts of Brazil will enter the area. It is not clear what infrastructure will be in place to support them.PracticalA number of studies have cast doubt on the economic viability of the project. The ex-President of Sapesp, the Sao Paulo state water company , has claimed it will be one of the most inefficient hydroelectric power projects in Brazilian history. Mainly because of the seasonal nature of water supply via the Xingu river, so that it will be at 30% capacity or less from June to October.Actually there is a solution to that - another dam. Although the intention is vehemently denied, a further dam at Altamira up stream would create a 2,000 sq mile lake and a year round water supply, making the whole project much more viable. It would also displace another estimated 25,000 people. The long term intention to build another dam would be easier to dismiss if the turbine capacity of the planned power stations were not considerably more than the likely water flow.Another artists impressionEnvironmentalConstruction of the dam required an environmental licence from IBAMA, the Brazilian environmental agency, and this was granted in February 2010. Controversially. Two IBAMA presidents and at least two senior officials have resigned claiming undue government pressure to approve the licence. Even now, the licence is technically provisional with many requirements yet to be met before a full licence can be granted, but that is moot as a judge has ruled that work can commence without a full licence.Large amounts of forest will inevitably be lost. One concern is the loss of biodiversity as a number of species are found only within the area affected by the dam, and it is extremely unlikely they would survive the drying out and/or flooding of their habitats. This apparently includes the Plant eating piranha Ossubtus xinguense (actually it's omnivorous and will eat worms and shrimps) and the Xingu poison dart frog Allobates crombie, amongst others.What is certain is that it is not just the area under the construction that will be affected. The influx of tens of thousands of migrants will consume a huge area of forest for building of homes and roads, and then farm land to support them.Further ReadingFearnside, P. (2006). Dams in the Amazon: Belo Monte and Brazil’s Hydroelectric Development of the Xingu River Basin Environmental Management, 38 (1), 16-27 DOI: 10.1007/s00267-005-0113-6Sousa Júnior, W.C. and Reid, J. 2010. Uncertainties in Amazon hydropower development: Risk scenarios and environmental issues around the Belo Monte dam. Water Alternatives 3, 249-268... Read more »

Fearnside, P. (2006) Dams in the Amazon: Belo Monte and Brazil’s Hydroelectric Development of the Xingu River Basin. Environmental Management, 38(1), 16-27. DOI: 10.1007/s00267-005-0113-6  

  • June 2, 2011
  • 06:51 PM
  • 670 views

Super bugs and Super sleuths

by Sarah Stephen in An ecological oratorio

Earlier this week on Monday came reports from Germany that 6 people who consumed raw vegetables were killed and hundreds rendered ill . Initial investigations pointed towards consumptions of raw cucumber, lettuce and tomatoes. The fatalities were attributed to hemolytic-uremic syndrome, or HUS, from E. Coli. Since then, more people have died and the infection has spread to different parts of Europe . Cases have been reported from Sweden, Austria, Denmark, France, Netherlands, Norway, Spain, Switzerland and the United Kingdom. At the initial stages opinions about whether the strain was new differed between scientists. Scientists at the Beijing Genomic Institute called it a new "super-toxic" E. coli strain whilst the U.S. Centers for Disease Control and Prevention said that it was a known strain.Today the WHO announced that the German strain was novel and that it had never been isolated before in humans. With the death toll having risen to 18, whilst over 1000 people remain ill, German scientists are desperately trying to sequence the bacterial genome. The news from WHO also indicates that the strain had never been found in any animals which signifies that it could have come directly from the environment into humans. The scientific community is awaiting with bated breath for the results from sequencing of the genome of this deadly strain of bacteria . The sequence of this strain of E.coli might explain the differential infection pattern observed- the bacteria is mostly infecting adults, and generally women.Emergence of super-bugs are of grave concern. In April, the Lancet reported bacteria carrying a gene that confers resistance to a major class of antibiotics identified in samples of drinking water and sewage effluents from New Delhi. This gene blaNDM-1 encodes the enzyme New Delhi metallo-β-lactamase 1 (NDM-1). Bacteria can pass genes easily through plasmids. The enzyme blocks the activity of a range of antibiotics. NDM-1-positive strains of both species have previously been found in hospitals in India and Pakistan and have already been seen in the United Kingdom and elsewhere in patients, some of whom had previously been in hospitals in the Indian subcontinent.The problem with virulent bacteria as with most infectious agents is that it is hard to be confined. As of now, the source of the German E.coli strain has not been pin pointed. With bacterial outbreaks such as this there is nothing called a ‘local problem’ but a ‘global problem’ and combating it requires a concerted effort where the blame game doesn’t help much.References:German E. coli outbreak caused by previously unknown strain (Nature, June 2nd, 2011)World health officials scramble to stem deadly E. coli outbreak (CNN, June 2nd, 2011)EHEC outbreak: Rare strain of E. coli unknown in previous outbreaks (WHO, June 2nd, 2011)Kumarasamy KK, Toleman MA, Walsh TR, Bagaria J, Butt F, Balakrishnan R, Chaudhary U, Doumith M, Giske CG, Irfan S, Krishnan P, Kumar AV, Maharjan S, Mushtaq S, Noorie T, Paterson DL, Pearson A, Perry C, Pike R, Rao B, Ray U, Sarma JB, Sharma M, Sheridan E, Thirunarayan MA, Turton J, Upadhyay S, Warner M, Welfare W, Livermore DM, & Woodford N (2010). Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. The Lancet infectious diseases, 10 (9), 597-602 PMID: 20705517Poirel L, Hombrouck-Alet C, Freneaux C, Bernabeu S, & Nordmann P (2010). Global spread of New Delhi metallo-β-lactamase 1. The Lancet infectious diseases, 10 (12) PMID: 21109172... Read more »

Kumarasamy KK, Toleman MA, Walsh TR, Bagaria J, Butt F, Balakrishnan R, Chaudhary U, Doumith M, Giske CG, Irfan S.... (2010) Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. The Lancet infectious diseases, 10(9), 597-602. PMID: 20705517  

Poirel L, Hombrouck-Alet C, Freneaux C, Bernabeu S, & Nordmann P. (2010) Global spread of New Delhi metallo-β-lactamase 1. The Lancet infectious diseases, 10(12), 832. PMID: 21109172  

  • January 29, 2011
  • 01:12 PM
  • 475 views

Waste lands

by Sarah Stephen in An ecological oratorio

Modern cities generate huge amounts of rubbish, and disposing of this is one of the most pressing environmental problems. One can bury it of course, or burn it in incinerators, or just dump it in a big pile just outside the city. This is the approach chosen for the Jardim Gramacho in Rio, Brazil, one of the worlds largest rubbish dumps, which is the subject of the Oscar nominated film, Waste Land.*Seventy percent of Rio's rubbish arrives at Jardim Gramacho, which is an astonishing 7,000 tons every day. In a rich country with few people, trash can be passed through automated factories which remove the most valuable materials for recycling. Brazil is a not-so-rich country with a lot of people, but recycling still takes place, on a massive scale. Thousands of scavengers ("catedores") clamber over the rubbish very day - an estimated 3,000 people, supporting 13,000 men women and children. About 200 tons of material is recycled daily, 50% plastic, 21% metal and 16% paper, though metal is preferred as the most vulnerable.The catedores, incidentally, don't necessarily conform to the expected stereotype. A survey in 2004** found 90% could read and write, and 79% own their own homes. The catedores are also reported as feeling a certain amount of pride in their efforts, contrasting with other job options such as drug trafficking or prostitution.Well so far so good, the system does generate meaningful employment and recycling is a good thing, but obviously there is a price.In the 2004 survey, although 70% used gloves only 0.9 use masks. Over 20% reported "colds or flu" in the previous 6 months and 10% had respiratory problems, whilst 45% had had conjunctivitis at some time in their past. There is also the ever present risk of cuts from glass, falling objects and burns, as well as bites from the mosquitoes which thrive in the marshes nearby, with 23% having had dengue fever. Interestingly, only 13% of those interviewed actually regarded their work as responsible for these problems, as opposed to their life in general. They may have had a point. Collecting rubbish will never make you rich, only 50% in 2004 lived in homes connected to the sewage network and ironically, about a third have no rubbish collection at home and have to burn rubbish or dump it in local waterways.One last point. Several cities such as Salvador and Recife, in northern Brazil, dump their rubbish near the airport, a text book example of an idea that "seemed a good idea at the time". After all nobody wants to live right next to a busy airport. Unfortunately, whilst people won't, vultures will. Black vultures are flourishing on the easily available food, and birds and planes do not mix. Bird strikes have more than doubled in Brazil in the past decade, and about half the cases involve vultures. Whilst a jet airliner might shrug off a hit from a sparrow, vultures are big weighing up to 2.5 kg and at least two two planes have been forced to make emergency landing after pilots were injured by vultures crashing into their windscreens. So far there have been no fatalities, but the potential is there and relocating or even killing the vultures has had limited success.As Wagner Fischer, coordinator of the wildlife management department at IBAMA, the Brazilian federal environmental oversight agency, is quoted as saying***, “What if you have a bunch of house flies in your home?, is it better to kill or relocate the flies or clean your house?”* The film incidentally follows artist Vik Muniz creating art from recycled materials, in collaboration with various catadores (hunters). It's a tribute to Muniz's talent that he has generated a very successful career from such unlikely material, including even the title sequence of the recent hugely popular Brazilian soap, Passione.** Porto, M, Junca, D, Goncalves, R Filhote, M. (2004). Garbage, work, and health: a case study of garbage pickers at the metropolitan landfill in Rio de Janeiro, Brazil. Cad. Saúde Pública [online]. vol.20, n.6, pp. 1503-1514. ISSN 0102-311X. doi: 10.1590/S0102-311X2004000600007.http://www.scielo.br/scielo.php?script=sci_abstract&pid=S0102-311X2004000600007&lng=en&nrm=iso&tlng=en*** http://www.brazilmax.com/news.cfm/tborigem/tt_prstuff/id/2Porto MF, Juncá DC, Gonçalves Rde S, & Filhote MI (2004). [Garbage, work, and health: a case study of garbage pickers at the metropolitan landfill in Rio de Janeiro, Brazil]. Cadernos de saude publica / Ministerio da Saude, Fundacao Oswaldo Cruz, Escola Nacional de Saude Publica, 20 (6), 1503-14 PMID: 15608851... Read more »

Porto MF, Juncá DC, Gonçalves Rde S, & Filhote MI. (2004) [Garbage, work, and health: a case study of garbage pickers at the metropolitan landfill in Rio de Janeiro, Brazil]. Cadernos de saude publica / Ministerio da Saude, Fundacao Oswaldo Cruz, Escola Nacional de Saude Publica, 20(6), 1503-14. PMID: 15608851  

  • August 27, 2010
  • 02:55 AM
  • 447 views

Effect of climate change on human morbidity and mortality and sea levels

by Sarah Stephen in An ecological oratorio

Climate change has been resulting in quite a many detrimental manifestations which tend to have a domino effect: fluctuations in temperature and precipitation (resulting in climate variability), as well as extreme manifestations such as drought, storms, rise in sea levels, and frequent severe weather events.Consider the research by Grinsted et al (2009) who used a ‘physically plausible four parameter linear response equation’ to relate nearly 2,000 years of global temperatures and sea level. Assuming that this relationship holds from 200 to 2100 AD, IPCC’s temperature scenarios and reconstructed past sea level scenarios were used to visualise future sea level scenarios. The result suggests that climate change will lead to a 0.9-1.3 m change in sea level between 2090-2099. This bodes a certain flooding of low lying coastal regions and islands. Island countries such as Maldives would practically cease to exist. Whilst countries such as Bangladesh may not face such obliteration, such a sea level rise would flood 1/3rd of the country, displacing millions of humans and severely affecting agriculture, irrigation, and livestock.Climate change also has a perceptible impact on human morbidity and mortality (Patz et al, 2005). Climate fluctuations have been linked to diseases and ailments- the evident effects of heat/cold (which, for instance, follows a U-shaped dose-response function with increased mortality in the extreme heat and cold), traumatic physical and mental ailments, and even cardiovascular and respiratory illnesses. This even results in altered transmission of infectious diseases (for instance, changes in temperature has been associated with salmonellosis in Europe and cholera in the ‘American south-west’; whilst, changes in rainfall has been associated with Rift valley fever in East Africa, and Hantavirus pulmonary syndrome and cholera in the American south-west and Bangladesh). When one factors in the effects of climate change on air pollution and the greater ecosystem, the result is quite chaotic. If the future projections of climate change are plausible, then it is likely that these health risks may rise significantly. The ‘potentially vulnerable’ regions includes the temperate latitudes (which may warm disproportionately), and the regions in and around the Pacific and Indian oceans (substantial rainfall variability).But even though the economic North/developed countries are responsible for most of the greenhouse gas emissions, the damaging effects of their actions are most perceived in the poor countries of the South which has (as of yet) contributed least towards the GHG emissions. References:Patz, J., Campbell-Lendrum, D., Holloway, T., & Foley, J. (2005). Impact of regional climate change on human health Nature, 438 (7066), 310-317 DOI: 10.1038/nature04188Grinsted, A., Moore, J., & Jevrejeva, S. (2009). Reconstructing sea level from paleo and projected temperatures 200 to 2100 ad Climate Dynamics, 34 (4), 461-472 DOI: 10.1007/s00382-008-0507-2... Read more »

Patz, J., Campbell-Lendrum, D., Holloway, T., & Foley, J. (2005) Impact of regional climate change on human health. Nature, 438(7066), 310-317. DOI: 10.1038/nature04188  

Grinsted, A., Moore, J., & Jevrejeva, S. (2009) Reconstructing sea level from paleo and projected temperatures 200 to 2100 ad. Climate Dynamics, 34(4), 461-472. DOI: 10.1007/s00382-008-0507-2  

  • August 19, 2010
  • 10:04 AM
  • 300 views

Where did the oil go?

by Sarah Stephen in An ecological oratorio

The recent oil spill in the Gulf of Mexico released, as we have all seen on tv, a lot of oil. Quite how much is a "lot" is a bit of a guess, but roughly 4.9 million barrels, or 784 million litres*. What actually happened to this oil was reviewed recently in an article in Science (Kerr 2010). Only about 0.1% was recovered from beaches and marshes (that´s still an awful lot of oil!). About 17% was siphoned away at the well head, 5% burned off at the surface, and only 3% skimmed off by booms, despite a lot of effort and money spent. And the other 75%? It's, er, disappeared.So where did this oil go? Some evaporated, but with luck most of it was eaten.Oil is energy, that's why we use it in our cars and power stations. And energy means food. There are actually quite a few bacteria that digest and breakdown crude oil, and these are massively important in the recovery of the ocean from disasters like this. They work as a consortium, each concentrating on a particular fraction of the oil, and as one hydrocarbon is degraded to another, other bacteria take over. The first, and so in many ways the most important, are Alcanivorax species (Vila et al 2010). These are found in tiny quantities in unpolluted waters, but their numbers rocket when in the presence of linear and branched alkanes, common in crude oil. In fact they are so specialised for this type of hydrocarbon that without long chain alkenes they grow very poorly, but by then their job is done. Now other species such as Roseovarius and Marinobacter take over.This breakdown was helped by the massive release of chemical dispersants at the oil head, 1.1 million gallons (Kintisch 2010). These are similar to the detergent in your kitchen, breaking down lumps of oil into tiny droplets, which are "dispersed" and can be attacked much more efficiently by bacteria. This was very controversial, as dispersants are pretty toxic and an immense quantity was involved. Still, it seemed to work, and much of the oil was broken down into 1-10 micrometer droplets. In fact, it started to raise fears that it was working TOO well, a microbial explosion depriving the ocean floor of oxygen and creating a huge dead zone. But this seems not to have happened, and in fact so far the prognosis is good.We´re not out of the woods yet, the oil could yet turn up in unwanted places, and chemical damage by detergents might yet, for instance, devastate the local tuna population. But there have been lessons learnt for next time - and there will be a next time.Kerr RA (2010). Gulf Oil Spill. A lot of oil on the loose, not so much to be found. Science (New York, N.Y.), 329 (5993), 734-5 PMID: 20705818http://www.sciencemag.org/cgi/content/full/sci;329/5993/734?maxtoshow=&hits=10&RESULTFORMAT=&fulltext=oil biodegradation&searchid=1&FIRSTINDEX=0&sortspec=date&resourcetype=HWCITKintisch E (2010). Gulf Oil Spill. An audacious decision in crisis gets cautious praise. Science (New York, N.Y.), 329 (5993), 735-6 PMID: 20705819http://www.sciencemag.org/cgi/content/full/329/5993/735Vila, J., Nieto, J., Mertens, J., Springael, D., & Grifoll, M. (2010). Microbial community structure of a heavy fuel oil-degrading marine consortium: linking microbial dynamics with polycyclic aromatic hydrocarbon utilization FEMS Microbiology Ecology DOI: 10.1111/j.1574-6941.2010.00902.x* the oil "barrel" is actually based on a type of old English wine barrel or "teirce" holding 35 gallons.... Read more »

Kerr RA. (2010) Gulf Oil Spill. A lot of oil on the loose, not so much to be found. Science (New York, N.Y.), 329(5993), 734-5. PMID: 20705818  

Kintisch E. (2010) Gulf Oil Spill. An audacious decision in crisis gets cautious praise. Science (New York, N.Y.), 329(5993), 735-6. PMID: 20705819  

Vila, J., Nieto, J., Mertens, J., Springael, D., & Grifoll, M. (2010) Microbial community structure of a heavy fuel oil-degrading marine consortium: linking microbial dynamics with polycyclic aromatic hydrocarbon utilization. FEMS Microbiology Ecology. DOI: 10.1111/j.1574-6941.2010.00902.x  

  • June 16, 2010
  • 08:47 AM
  • 262 views

Paper of the Week : A Whale of the waste matter

by Sarah Stephen in An ecological oratorio

The way by which living organisms in our planet are intricately connected is beautiful beyond comprehension. Like pieces in a puzzle they all fit together with the activities of each organism however trivial it may appear to be, affecting the existance of others. We will never fully understand this marvel, but a noteworthy example is the elegant finding by Lavery et al published in the Proceedings of the Royal Society (Biological Sciences)- Iron defecation by sperm whales stimulates carbon export in the Southern Oceanhttp://rspb.royalsocietypublishing.org/content/early/2010/06/14/rspb.2010.0863.fullThe authors provide compelling evidence on the role that sperm whales (Physeter macrocephalus) in the Southern ocean play in promoting nutrient cycling and their function as carbon sinks. Lavery et al show that the whales consume prey at the depths of the ocean but expel the waste about 50 tonnes of iron iron-rich liquid buoyant faecal matter each year into the photic zone near ocean surface. The researchers estimate that if three quarters of this iron persisted there, 36 tonnes of iron to the photic zone per year are contributed by the activities of the Southern Ocean sperm whale alone. Iron is a nutrient essential for the growth of phytoplanton which live in the photic zone. Consequentially, iron enrichment causes phytoplankton blooms resulting in carbon export during photosythesis. Additionally, phytoplankton are consumed by zooplankton. The zooplankton are consumed by squids that form the food of the whales, thereby creating a positive feedback loop. Thus this toilette behaviour of the whale benefits it as well! The researchers estimate that sperm whales stimulated the export of 4 × 105 tonnes of carbon per year to the deep ocean whilst respiring 2 × 105 tonnes of carbon per year thereby mopping up carbon. This paper also highlights the issue as to how industrial whaling leading to large scale depletion of sperm whales might have impeded the ability of the Southern Ocean to act as a carbon sink. Lavery, T., Roudnew, B., Gill, P., Seymour, J., Seuront, L., Johnson, G., Mitchell, J., & Smetacek, V. (2010). Iron defecation by sperm whales stimulates carbon export in the Southern Ocean Proceedings of the Royal Society B: Biological Sciences DOI: 10.1098/rspb.2010.0863... Read more »

Lavery, T., Roudnew, B., Gill, P., Seymour, J., Seuront, L., Johnson, G., Mitchell, J., & Smetacek, V. (2010) Iron defecation by sperm whales stimulates carbon export in the Southern Ocean. Proceedings of the Royal Society B: Biological Sciences. DOI: 10.1098/rspb.2010.0863  

  • May 31, 2010
  • 05:26 AM
  • 419 views

Paper of the Week: Humans and Biodiversity

by Sarah Stephen in An ecological oratorio

A new study interestingly implies that human activities may not always be bad for biodiversity. Long before the colonizers arrived in South America, indigenous farmers, belonging to the Arauquinoid cultures, had already interfered with the Amazonian biodiversity. Their novel agricultural engineering methods had changed the savannah ecosystem, resulting in increased biodiversity. Thus states the solid paper, on 'Pre-Columbian agricultural landscapes, ecosystem engineers, and self-organized patchiness in Amazonia', published in Proceedings of the National Academy of Sciences (online before print, April 12th 2010), by Doyle McKey (Université de Montpellier II, France), Stéphen Rostain, José Iriarte, Bruno Glaser, Jago Jonathan Birk, Irene Holst, and Delphine Renard. The savannahs of coastal Guyana tend to flood during the rains and are dry during the summer. However, strange complexes of mounds are seen in the terrain of these plains, running for 360 miles from Berbice River to Cayenne. Due to their perfect symmetry, the mounds were deduced to be man-made. The mounds drained well during the rains and floods (their drainage capacity was nine times as high as the seasonally flooded savannah). The authors deduce that these are large raised beds/fields, made out of the surrounding topsoil, for cultivating crops (a theory further substantiated by soil samples containing microfossils of maize, cassava, and squash), constructed by the pre-Columbian farmers, around 1000-700 years ago. The interesting point is that this farming was practiced in wastelands considered to be unsuitable for agriculture- a feat achieved due to their effective agricultural engineering. When these fields were abandoned, the mounds were colonised by flora and fauna, thus creating a new ecosystem. These 'ecosystem engineers' (viz., ants such as Acromyrmex octospinosus and Ectatomma brunneum, termites such as Nasutitermitinae, and earthworms) built their nests on the raised beds so that the colonies wouldn't be flooded. Their burrowing aerated it further, helping in accumulating sufficient rainfall. Moreover, the mounds were fertilised as a result of them congregating organic matter into their nests and accumulating minerals such as nitrogen, potassium, and calcium. As a result, the perennial plants on the mounds flourished and their strong roots prevented the erosion of the mound. All of these alterations initiated by humans have resulted in a higher biodiversity than seen in the normal savannahs. This study would give additional impetus to the debate over whether most of the Amazon rainforest and savannahs (commonly considered to be pristine) are sites of significant human occupation, especially during the pre-Columbian times. The authors suggest that this agricultural system could be a model for modern farming, especially considering the beneficial ecological changes. Although this is a perfect example of a terrain modified by humans and maintained by Nature, it must be noted the increase in biodiversity was a result of 400-800 years of no/minimal human intervention. Secondly, the ‘punja’ technique of rice/paddy cultivation has a very similar methodology and is followed in parts of Kerala. link: http://www.pnas.org/content/early/2010/04/07/0908925107.abstract?sid=93317154-3ce6-43c8-9a1e-456e24272c2bMcKey D, Rostain S, Iriarte J, Glaser B, Birk JJ, Holst I, & Renard D (2010). Pre-Columbian agricultural landscapes, ecosystem engineers, and self-organized patchiness in Amazonia. Proceedings of the National Academy of Sciences of the United States of America, 107 (17), 7823-8 PMID: 20385814... Read more »

McKey D, Rostain S, Iriarte J, Glaser B, Birk JJ, Holst I, & Renard D. (2010) Pre-Columbian agricultural landscapes, ecosystem engineers, and self-organized patchiness in Amazonia. Proceedings of the National Academy of Sciences of the United States of America, 107(17), 7823-8. PMID: 20385814  

  • May 31, 2010
  • 05:23 AM
  • 381 views

Paper of the week: Effects of prenatal exposure of pthalates

by Sarah Stephen in An ecological oratorio

Pthalates are esters of pthalic acid that are commonly added to plastics but also are found in diverse products ranging from cosmetics to pharmaceutical pills. As could be expected, studies that monitor phthalate metabolites in human populations have shown that they are widely present. Over the years, there have been many concerns over their effect on human health notably as hormonal disrupting agents. This has led to the regulation of some phthalates in consumer products in Europe and the United States, which in some cases,have been replaced with others. Recent evidences indicate that endocrine disruption might only be a tip of the iceberg and that pthalates might have other health effects as well.It is well known that maternal exposure of pollutants make their way to the offspring and in many cases can have deleterious consequences. It appears that this dogma can also be applied to the case of the pthalates. In a study by Engel et al published in Environmental health perspectives,http://ehp03.niehs.nih.gov/article/fetchArticle.action;jsessionid=E899A81379071E8E095EF53E962F597F?articleURI=info%3Adoi%2F10.1289%2Fehp.0901470the authors questioned whether there was any association between prenatal phthalate exposure to the behavior of offspring. The study occurred in a multiethnic prenatal population enrolled in the Mount Sinai Children’s Environmental Health Study in New York City between 1998 and 2002. Urine samples of mothers during the third-trimester of pregnancy was collected and analyzed for phthalate metabolites. Subsequently, cognitive and behavioral development of the children was assessed between the ages of 4 and 9. Interestingly, the scientists found that increased concentrations of low-molecular-weight (LMW) phthalate metabolites in the mothers were associated with poorer scores on aggression, conduct problems, attention problems, and depression in the children. These results led them to conclude that behavioral domains adversely associated with prenatal exposure to LMW phthalates in this study are commonly affected in children clinically diagnosed with conduct or attention deficit hyperactivity disorders.This study and several of its predecessors, extend the known adverse effects of pthalates, which calls for increased caution. What is urgently needed are more hard core studies elucidating the toxicology of pthalates and their metabolites, that will help us understand the consequences of exposure. However, these studies will take time; the evidence at hand should motivate nations to re-evaluate their policies on pthalates and enforce strict regulations.Pthalates are esters of pthalic acid that are commonly added to plastics but also are found in diverse products ranging from cosmetics to pharmaceutical pills. As could be expected, studies that monitor phthalate metabolites in human populations have shown that they are widely present. Over the years, there have been many concerns over their effect on human health notably as hormonal disrupting agents. This has led to the regulation of some phthalates in consumer products in Europe and the United States, which in some cases,have been replaced with others. Recent evidences indicate that endocrine disruption might only be a tip of the iceberg and that pthalates might have other health effects as well.It is well known that maternal exposure of pollutants make their way to the offspring and in many cases can have deleterious consequences. It appears that this dogma can also be applied to the case of the pthalates. In a study by Engel et al published in Environmental health perspectives,http://ehp03.niehs.nih.gov/article/fetchArticle.action;jsessionid=E899A81379071E8E095EF53E962F597F?articleURI=info%3Adoi%2F10.1289%2Fehp.0901470the authors questioned whether there was any association between prenatal phthalate exposure to the behavior of offspring. The study occurred in a multiethnic prenatal population enrolled in the Mount Sinai Children’s Environmental Health Study in New York City between 1998 and 2002. Urine samples of mothers during the third-trimester of pregnancy was collected and analyzed for phthalate metabolites. Subsequently, cognitive and behavioral development of the children was assessed between the ages of 4 and 9. Interestingly, the scientists found that increased concentrations of low-molecular-weight (LMW) phthalate metabolites in the mothers were associated with poorer scores on aggression, conduct problems, attention problems, and depression in the children. These results led them to conclude that behavioral domains adversely associated with prenatal exposure to LMW phthalates in this study are commonly affected in children clinically diagnosed with conduct or attention deficit hyperactivity disorders.This study and several of its predecessors, extend the known adverse effects of pthalates, which calls for increased caution. What is urgently needed are more hard core studies elucidating the toxicology of pthalates and their metabolites, that will help us understand the consequences of exposure. However, these studies will take time; the evidence at hand should motivate nations to re-evaluate their policies on pthalates and enforce strict regulations.Engel SM, Miodovnik A, Canfield RL, Zhu C, Silva MJ, Calafat AM, & Wolff MS (2010). Prenatal phthalate exposure is associated with childhood behavior and executive functioning. Environmental health perspectives, 118 (4), 565-71 PMID: 20106747... Read more »

Engel SM, Miodovnik A, Canfield RL, Zhu C, Silva MJ, Calafat AM, & Wolff MS. (2010) Prenatal phthalate exposure is associated with childhood behavior and executive functioning. Environmental health perspectives, 118(4), 565-71. PMID: 20106747  

  • May 29, 2010
  • 01:27 PM
  • 319 views

Paper of the Week: Beware the Lead

by Sarah Stephen in An ecological oratorio

Staunch supporters of game will find little to be pleased with the research published by Deborah Pain (of Wildfowl and Wetlands Trust, Gloucestershire) and colleagues, on Potential Hazard to Human Health from Exposure to Fragments of Lead Bullets and Shot in the Tissues of Game Animals in PLoS. The findings would also shock those who happily dig into the cooked game, seldom pondering about how much lead is ingested in the process.Lead ammunition (pellets/bullets) is often used to shoot down game. To solve their research question, Pain and her colleagues bought wild-shot game birds (grouse, mallard, partridge, pheasant, pigeon, and woodcock) from supermarkets, game dealers, shoots, and butchers. After X-raying these to determine the number of shot and shot fragments present, these were cooked using typical recipes (in wine or cider or pH-neutral cream sauce). Mimicking the traditional game eating behaviour, the visible lead fragments were manually removed.The lead concentrations in the remaining flesh were analysed. The results demonstrated that the game tissue is littered with small pieces of shot- most likely due to the ammunition disintegrating into smaller particles upon impact (and, in some cases, these fragments embed into the tissues even though the shot exits the body). Consequently, a higher level of consumption of some species may result in exceeding the current FAO/WHO’s weekly tolerable intake of lead. For instance, weekly consumption of three meals of woodcock and/or ten meals of grouse / partridge / pheasant would certainly take a 70 kilogram person over this threshold.So does the consumption of game birds (shot with lead) pose a threat to humans? – The answer is very much an ‘yes’ although this depends on the amount of game consumed. As in most studies, the vulnerable population stands a good risk. And one mustn’t overlook the impact on the food chains/webs- fauna which consume these shot game birds are inevitably affected as well. Pain DJ, Cromie RL, Newth J, Brown MJ, Crutcher E, Hardman P, Hurst L, Mateo R, Meharg AA, Moran AC, Raab A, Taggart MA, & Green RE (2010). Potential hazard to human health from exposure to fragments of lead bullets and shot in the tissues of game animals. PloS one, 5 (4) PMID: 20436670... Read more »

Pain DJ, Cromie RL, Newth J, Brown MJ, Crutcher E, Hardman P, Hurst L, Mateo R, Meharg AA, Moran AC.... (2010) Potential hazard to human health from exposure to fragments of lead bullets and shot in the tissues of game animals. PloS one, 5(4). PMID: 20436670  

  • February 26, 2010
  • 02:38 PM
  • 270 views

Sunlight on the sea

by Sarah Stephen in An ecological oratorio

In this last week the Brazilian cities of Sao Paulo and Recife have experienced records levels of UV exposure. While a UV index of 6-7 is ¨high risk", and "very high risk" is 8-10, Sao Paulo was scorched with an index of 14. As the sun burns us it also beats down on the ocean surface and the algae that live there. What happens next is the subject of the CLAW hypothesis, which proposes a negative feedback loop, as follows.....Dimethylsulphide produced by phytoplankton is oxidised by bacteria to produce a sulphate aerosol on the sea surface which is a major source of cloud condensation nuclei. So more clouds, less photosynthesis and a feedback loop.That´s fine, but of course the real world is much more complicated than that. For instance, solar radiation is a double edged sword. There is increased photosynthesis, and temperature for growth, but what of UV? UV-B damages DNA in the bacteria required for DMS oxidation, killing them. It also harms the phytoplankton, who respond by producing anti-oxidants, including DMS. Together these factors increase considerably the amount of DMS in the ocean, so oceanic [DMS] and levels of UV are linked through the year. But DMS in the atmosphere and the surface waters is attacked by UV, leading to it´s photo destruction.So what happens when UV increases beyond previous levels? Does the extra production of DMS still lead to more cloud cover, a negative feedback? Or does UV kill off the oxidising bacteria and cause photodestruction in the atmosphere, leading to less cloud clover, and in turn, more UV exposure - a positive feedback loop? Oceanic acidification, as described previously by Ruth, changes water chemistry and inhibits phytoplankton growth, and so complicates matters still further.The processes mentioned here take place on such a massive scale that they affect deeply the world climate. They are incredibly complex, and rely on a interlinked series of feedback loops. What happens when feedback is disrupted has yet to be seen.For more detail see;Miles, CJ, Bell, TG, Lenton, TM 2009. Testing the relationship between the solar radiation dose and surface DMS concentrations using ub situ data. Biogeosciences, 6, 1927-1934.Miles, C., Bell, T., & Lenton, T. (2009). Testing the relationship between the solar radiation dose and surface DMS concentrations using in situ data Biogeosciences, 6 (9), 1927-1934 DOI: 10.5194/bg-6-1927-2009... Read more »

Miles, C., Bell, T., & Lenton, T. (2009) Testing the relationship between the solar radiation dose and surface DMS concentrations using in situ data. Biogeosciences, 6(9), 1927-1934. DOI: 10.5194/bg-6-1927-2009  

  • February 21, 2010
  • 12:39 PM
  • 502 views

Paper of the week: What ocean acidification means for the plankton

by Sarah Stephen in An ecological oratorio

It appears that we humans had taken oceans for granted for too long. A widely known fact is that most of what we discard makes its way to oceans. Oceans are sinks for all things including 1/3 of the carbon dioxide that has been released in the last 200 years. This has resulted in the acidification of the oceans. The science behind is that carbonic acid is formed when carbon dioxide dissolves in sea water. This raises the hydrogen ion concentration and bicarbonate ions, but limits carbonate ions. This interferes with the ability of many marine plankton to build shells. We are just beginning to understand how anthropogenic ocean acidification affects marine ecosystems and the long term consequences of this phenomenon. A report released from a team of over 100 European scientists during the Copenhagen Summit highlights this fact and alleged that marine species are being affected by the acidification of the oceans which according to the scientists are irreversible. According to the document, acidification is occurring at such a rapid pace increasing by 30% since industrial revolution and states that if CO2 emissions are not curtailed it will severely affect coral reefs, and algae. This prompts the question asking whether the acidification of oceans is uniform & universal? It seems not so, with oceans around the globe showing different degrees of acidification. North Atlantic, Pacific and Arctic seas are predicted to be affected by this phenomenon the most.Is there any cause for concern? Absolutely, The effect of acidification on plankton cannot be trivialised as they are the powerhouses and form the lower echelons of the ecosystem on which the larger vertebrates subsist.Where does the evidence for the acidification affecting plankton come from? There is convincing evidence from studies on limited species- cocolithophores and formaniferans. But there are caveats, as previous studies by different research groups on cocolithophore species had shown that not all species behave in the same way to increased carbon dioxide levels. While some species show decreased calcification , others show no change , yet another show non linear calcification and interestingly some show increased calcification. In addition, closely related organisms such as tropical and temperate sea urchins showed different responses to acidification. Even among same species, results from different laboratories showed contrasting effects. A reason for this has been attributed to different methods the labs used in mimicking acidification. Other reasons could be due to difference in experimental conditions, for example access of the species to nutrientss , temperature etc, all of which can consequently affect the way the organisms respond. Although these are valid reasons, it will be hard to convince general public of the enormity of the situation with such conflicting results. This warrants further studies.The interests in ocean acidification has been rekindled recently by the publication of a research paper from some researchers from Princeton who have given a scientific basis explaining how acidification is deleterious to plankton. It all falls on iron which is a nutrient for phytoplankton. The chemistry of iron is extremely sensitive to pH and the acidification of the sea water will alter its availability to the planktons. Shi et al showed that acidification decreased the iron uptake of phytoplankton in the laboratory. The downside of this study is that the work was done in the laboratory and field studies are needed to corroborate this.Ocean acidification is a crtical issue and we should act urgently. Often action requires concrete evidence. A unified protocol experimental protocol that is followed globally would address many of the discrepancies posed by lab based research as advocated by the researcher Victoria Fabry. But the proof of the pudding are evidences of field work. However one only hopes that those will not uncover problems that have progressed to such an extent that it is a impossible to be mitigated.Shi et al, Science 327 (2010)http://www.sciencemag.org/cgi/content/abstract/327/5966/676Fabry VJ, Science 320 (2008)http://www.sciencemag.org/cgi/content/abstract/1157130v1(PS- The topic of mismanagement of oceans was touched upon in a previous blog 'Ten Years Hence' By David BussShi D, Xu Y, Hopkinson BM, & Morel FM (2010). Effect of ocean acidification on iron availability to marine phytoplankton. Science (New York, N.Y.), 327 (5966), 676-9 PMID: 20075213Fabry, V. (2008). OCEAN SCIENCE: Marine Calcifiers in a High-CO2 Ocean Science, 320 (5879), 1020-1022 DOI: 10.1126/science.1157130... Read more »

Shi D, Xu Y, Hopkinson BM, & Morel FM. (2010) Effect of ocean acidification on iron availability to marine phytoplankton. Science (New York, N.Y.), 327(5966), 676-9. PMID: 20075213  

Fabry, V. (2008) OCEAN SCIENCE: Marine Calcifiers in a High-CO2 Ocean. Science, 320(5879), 1020-1022. DOI: 10.1126/science.1157130  

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