Monday, 20 December 2010
Wednesday, 6 October 2010
The lake, with its pH of 7.25, serves as a major drinking water source for the inhabitants of the Kollam district. And the large population of chaoborus larvae (glassworm)* is believed to consume bacteria in the lake, thus maintaining the water’s purity. The aquatic fauna includes Etroplus suratensis (Pearl Spot or ‘karimeen’) and catfish. It is also a favourite habitat of the Common Teal (Anas crecca). Of special importance are Puntius ticto punctatus (the critically endangered Ticto barb), Horabagrus brachysoma (the endangered sun catfish), and Parambassis thomassi (vulnerable), as reported by WWF. WWF’s report also states that lake lacks aquatic flora and has scarce phytoplanktons**- claims which cannot be generalised for botanists have collected flora such as Nymphea, Limnanthemum, Lemna, Elodea, and Hydrilla from the lake.
The lake has been in the limelight recently- its environmental quality has been deteriorating, and both its surface area and the water level has been decreasing (in May 2010, 24 hectares of the lake was parched). The reasons are:
- Encroachment/reclamation for agriculture (mainly paddy, plantain, and tapioca)
- Unauthorised sand mining, including clay and sand mining in the surrounding hillocks which serves as catchments
- Soil erosion on the banks (the acacia trees which were planted with the purpose of stopping erosion have also stayed true to their reputation as water depleters).
-Dumping of agricultural and domestic wastes
- Dumping of wastes by restaurants and butchers
- Dumping of domestic/municipality sewage via gutters
- Soaking of dry coconut palm fronds before weaving
- The usual norm of local residents bathing and washing clothes (also cattle) in the lake.
- Accumulated eroded material at the bottom of the lake.
There may be some solution after all. The local government drew up a master plan for protecting the lake, and July 2010 saw those who lived around the lake being given a notice banning them from taking baths, washing clothes, or dumping waste into the lake. The notice also forbids mining in the catchments. In September, Sasthamcotta Lake and its surrounding catchments areas were declared as protected. Quarrying, sand-mining, and other activities which pollute the lake have been banned for two months. A longer term ban would have been more appropriate- a two month ban cannot achieve anything substantial, if any.
Whilst researching this topic, it was evident that the primary source used by most reports/articles was the Information Sheet on Ramsar Wetlands filed in by WWF, which may have a degree of inaccuracy.
* The WWF report’s ‘cavaborus larvae’ is probably a typo (or an ignorant error). Nonetheless, there are now 122 google results for the same term associated with the lake.
** A lake with no plants, minimal phytoplankton, and many fish species? Shurely shome mishtake?
Information Sheet on Ramsar Wetlands(RIS)
The Annotated Ramsar List: India
WWF on Sasthamkotta Lake
Friday, 17 September 2010
These facts were highlighted in a paper by Indira Devi (‘Pesticides in agriculture – A boon or a curse? A case study of Kerala’) published in the Economic and Political Weekly. The study focused on farms of mango and banana (in Palakkad and Wayanad districts), pineapple (in Ernakulam and Idukki districts), bitter gourd (in Idukki and Kottayam districts), and amaranthus and okra (in Palakkad and Trivandrum districts), and stated that 56% of mango farmers and 86% of banana farmers use chemical pesticides.
Even if there is an overall decrease in pesticide usage, the currently favoured and indiscriminately used pesticides are those that are potent in small doses, and relationally, more toxic. These include:
- PAN bad actor chemicals such as carbendazim, diuron, mancozeb, and paraquat (which are banned elsewhere for their highly toxic effects ranging from groundwater pollution to carcinogenic and teratogenic properties)
- Lindane, the highly toxic restricted-use pesticide, the usage of which has been increasing over the years (apparently with an annual compound growth rate of 107.54%)
- Cypermethrin, fenvalerate, and neem-based pesticides (which have an increase of 21-30%).
- The carcinogenic Methyl parathion (with an increase of 16.83%)
- Chloripyriphos (an increased usage of 7.5 %).
- The highly toxic Methoxyl ethyl mercury chloride.
- The banned Endosulphan (allegedly used in some mango plantations in Palakkad)
- The arsenic and phosophorus containing Calcium carbide (the effects of which ranges from digestive disorders to stroke and hypoxia), which is usually used as a ripening agent.
The chemical sprayings for mango comprises of various fractions/mixtures of carbaryl, cyperrmethrine, endosulfan, malathion, mercaptothion, planofix, profenofos, sevin, and sulphur. The number of pesticides used by farmers averages around 14 for banana, 15 for bitter gourd, and 11 for okra and amaranthus. Unsurprisingly, market surveys have revealed high levels of residual pesticide in vegetables and fruits grown in Kerala.
It is quite likely that the farmers who use these pesticides are ignorant of the injurious health effects posed by these chemicals, not just to the consumers but also to themselves. As far as they are concerned, they are using potent pesticides which are much more effective in accomplishing its purpose than the recommended and safer options. Perhaps they are in the same boat as most of us who seldom think before choosing cosmetic products.
Thursday, 16 September 2010
Thursday, 26 August 2010
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.
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
Thursday, 19 August 2010
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: 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
* the oil "barrel" is actually based on a type of old English wine barrel or "teirce" holding 35 gallons.
Wednesday, 4 August 2010
For thousands of years, Lead has been widely extracted and used by mankind, mainly due to the availability of its many ores as well as its malleability. In fact, Lead used to be the second most used metal (after Iron).
Despite its many benefits, Lead’s detrimental effects of morbidity and mortality in humans and animals have been demonstrated by numerous studies. These vary from mild manifestations (such as fatigue, emotional irritability, and insomnia) to the fatal conclusion of death. Published studies have established the following:
- reduced somatic growth (Hauser et al, 2008)
- impaired motor function (Cecil et al, 2008)
- decreased brain volume (Cecil et al, 2008)
- permanent cognitive damage, attention and behavioural dysfunction/problems, impaired cognitive function (Needleman et al, 2002; Canfield et al, 2003; Lanphear et al, 2005; Braun et al, 2006; Schnaas et al, 2006; Cecil et al, 2008; Jusko et al, 2008; Wright et al, 2008)
- reproductive damage, including spontaneous abortion (Borja-Aburto et al, 1999)
- nephropathy (Ekong et al, 2006)
- cancer and cardiovascular disease (Lustberg and Silbergeld, 2002; Menke et al, 2006)
- and even criminal behavior (Needleman et al, 2002; Wright et al, 2008).
A great danger of Lead toxicity is that the symptoms may lag physiological changes, i.e. the affected individual may remain unaware of the danger (similar to the effect of cholesterol). Lead in the blood does not excrete and a major proportion sequesters in soft tissues and bone from where it may be switched on especially during pregnancy (Tellez-Rojo et al, 2004) or old age (Schwartz and Stewart, 2007).
Over the past 50 years, as a result of new studies revealing the toxic effects of Lead at lower levels, the benchmark levels have declined (60 μg/dL in 1960; 25 μg/dL in 1985; and, 10 μg/dL in 1991) (Needleman, 2004). And although the current CDC benchmark level is 10 μg/dL, the published studies indicate that it would be inane to consider even a trifling level of Lead exposure as being harmless (Bellinger and Bellinger, 2006)- for instance, Lanphear et al (2005) has associated maximal blood Lead levels lower than 7.5 μg/dL with permanent cognitive damage and intellectual deficits in children, whilst Menke et al (2006) associated 2 µg/dL as having increased risk of cardiovascular mortality in adults.
Foetuses, children, and pregnant women face the greatest risk (Schnaas et al, 2006; Iqbal et al, 2009).
Borja-Aburto VH, Hertz-Picciotto I, Rojas Lopez M, Farias P, Rios C, & Blanco J (1999). Blood lead levels measured prospectively and risk of spontaneous abortion. American journal of epidemiology, 150 (6), 590-7 PMID: 10489998
Lustberg, M. (2002). Blood Lead Levels and Mortality Archives of Internal Medicine, 162 (21), 2443-2449 DOI: 10.1001/archinte.162.21.2443
Needleman HL, McFarland C, Ness RB, Fienberg SE, & Tobin MJ (2002). Bone lead levels in adjudicated delinquents. A case control study. Neurotoxicology and teratology, 24 (6), 711-7 PMID: 12460653
Canfield, R., Henderson, C., Cory-Slechta, D., Cox, C., Jusko, T., & Lanphear, B. (2003). Intellectual Impairment in Children with Blood Lead Concentrations below 10 μg per Deciliter New England Journal of Medicine, 348 (16), 1517-1526 DOI: 10.1056/NEJMoa022848
Needleman, H (2004). Lead poisoning Ann. Rev. Med (55), 209-222
Téllez-Rojo MM, Hernández-Avila M, Lamadrid-Figueroa H, Smith D, Hernández-Cadena L, Mercado A, Aro A, Schwartz J, & Hu H (2004). Impact of bone lead and bone resorption on plasma and whole blood lead levels during pregnancy. American journal of epidemiology, 160 (7), 668-78 PMID: 15383411
Lanphear BP, Hornung R, Khoury J, Yolton K, Baghurst P, Bellinger DC, Canfield RL, Dietrich KN, Bornschein R, Greene T, Rothenberg SJ, Needleman HL, Schnaas L, Wasserman G, Graziano J, & Roberts R (2005). Low-level environmental lead exposure and children's intellectual function: an international pooled analysis. Environmental health perspectives, 113 (7), 894-9 PMID: 16002379
Bellinger DC, & Bellinger AM (2006). Childhood lead poisoning: the torturous path from science to policy. The Journal of clinical investigation, 116 (4), 853-7 PMID: 16585952
Braun JM, Kahn RS, Froehlich T, Auinger P, & Lanphear BP (2006). Exposures to environmental toxicants and attention deficit hyperactivity disorder in U.S. children. Environmental health perspectives, 114 (12), 1904-9 PMID: 17185283
Ekong EB, Jaar BG, & Weaver VM (2006). Lead-related nephrotoxicity: a review of the epidemiologic evidence. Kidney international, 70 (12), 2074-84 PMID: 17063179
Menke, A. (2006). Blood Lead Below 0.48 mol/L (10 g/dL) and Mortality Among US Adults Circulation, 114 (13), 1388-1394 DOI: 10.1161/circulationaha.106.628321
Schnaas, L., Rothenberg, S., Flores, M., Martinez, S., Hernandez, C., Osorio, E., Velasco, S., & Perroni, E. (2005). Reduced Intellectual Development in Children with Prenatal Lead Exposure Environmental Health Perspectives, 114 (5), 791-797 DOI: 10.1289/ehp.8552
Schwartz, B., & Stewart, W. (2007). Lead and cognitive function in adults: A questions and answers approach to a review of the evidence for cause, treatment, and prevention International Review of Psychiatry, 19 (6), 671-692 DOI: 10.1080/09540260701797936
Cecil KM, Brubaker CJ, Adler CM, Dietrich KN, Altaye M, Egelhoff JC, Wessel S, Elangovan I, Hornung R, Jarvis K, & Lanphear BP (2008). Decreased brain volume in adults with childhood lead exposure. PLoS medicine, 5 (5) PMID: 18507499
Hauser, R., Sergeyev, O., Korrick, S., Lee, M., Revich, B., Gitin, E., Burns, J., & Williams, P. (2008). Association of Blood Lead Levels with Onset of Puberty in Russian Boys Environmental Health Perspectives, 116 (7), 976-980 DOI: 10.1289/ehp.10516
Jusko TA, Henderson CR, Lanphear BP, Cory-Slechta DA, Parsons PJ, & Canfield RL (2008). Blood lead concentrations Environmental health perspectives, 116 (2), 243-8 PMID: 18288325
Wright JP, Dietrich KN, Ris MD, Hornung RW, Wessel SD, Lanphear BP, Ho M, & Rae MN (2008). Association of prenatal and childhood blood lead concentrations with criminal arrests in early adulthood. PLoS medicine, 5 (5) PMID: 18507497
Iqbal S, Blumenthal W, Kennedy C, Yip FY, Pickard S, Flanders WD, Loringer K, Kruger K, Caldwell KL, & Jean Brown M (2009). Hunting with lead: association between blood lead levels and wild game consumption. Environmental research, 109 (8), 952-9 PMID: 19747676
Saturday, 26 June 2010
In January 2010 the Yale Centre of Environmental law and policy prepared a report for the World Economic Policy forum in Geneva. (http://epi.yale.edu/) They used a whole raft of factors, from air and water pollution to polices on climate change and biodiversity (if they were actually implemented - see Greece below).
So, cut to the chase, who won?? Well, the overall winner was Iceland, but I'm excluding them since a) they aren't at the World Cup Finals, and b) their volcanoes disrupted the skies of most of Europe! So, step forward.....
Switzerland! Second place overall. And they beat Spain! Despite not making the 2nd round its still a good time to be Swiss.
One would expect wealthy countries to top the list, as they can afford the necessary infrastructure, and indeed the 2nd place goes to France (7th officially), England/ UK are 4th (14th) and Germany 7th (17th), but actually commitment and good governance are even more important. Yale place Costa Rica an excellent 2nd and Slovakia make 3rd place in our table (13) despite inheriting an aging and polluting heavy industry from the Soviet era. Chile are 6th (16th), and the South American leaders.
So who are the bad boys? Bottom of the pack is Nigeria, in a large part due to problems with the oil industry there. Nigeria is home to the Niger valley, the largest wetland in Africa, but plagued with oil spills due to very poorly maintained equipment. These devastate local ecosystems, and eventually fisheries, combined with poor environmental policies and over fishing. Another problem is the flaring of natural gas associated with oil drilling - equivalent to 25% of the UK's gas usage in 2001, or 40% of Africa's. Of course this releases massive amounts of CO2 into the atmosphere,as well as damaging local heath from air pollution.
Second to last are North Korea, though to be fair to Nigeria, information from this closed state is notoriously unreliable and their rating rather a guess.
The worst performer in Latin America was Honduras, with Uruguay slightly in front. Honduras has had some well publicised political problems and coups, as well as being one of the poorest countries in Latin America, and thus the major environmental problem, deforestation, has had little priority. One of the major problems in Uruguay is pollution of their river estuaries. This has led to bitter disputes with Argentina, which shares a common border on the river Uruguay, especially over the building of new paper mills which discharge pulp into the river.
Worst scoring in our list for Europe, and 71st in the official list, was Greece. Deforestation has not helped, but their low score is mainly due to failure to implement obligations from their signature of the Kyoto treaty. Given their financial impecunity due to a not-totally-dissimilar failure to implement obligations over Euro membership, it is hard to see how things will improve in the short term.
But let's end on a good note. Switzerland for the Cup!!
Thursday, 17 June 2010
Providing an image/diagram is a good technique of deepening understanding of a concept; providing a demonstration would complete the picture. And this is exactly what Plastiki does.
The unique Plastiki
Plastiki is the innovative result of the impact which UNEP’s report, on ‘Ecosystems and Biodiversity in Deep Waters and High Seas’ (which presented the threats faced by marine biodiversity due to pollution, particularly by plastic wastes), had on eco-adventurer David de Rothschild. After months and years of brainstorming, Plastiki emerged - the 60 ft/18 m catamaran with a difference- manufactured mainly with solar energy and composed of 12500 reclaimed plastic bottles (about the same number of plastic bottles consumed every 8.3 seconds in the US) filled with CO2 to make her solid and consistent (and the bottles provide 68% of the buoyancy); structure made out of easily recyclable self-reinforced polyethylene terephthalate (srPET) called Seretex; sails made out of recycled PET; and recycled waste products. The catamaran is self-sustaining, using renewable energy systems (solar panels, wind and sea turbines, and a biodiesel engine to be used only in emergencies), and a vacuum water evaporator (for desalination). A bicycle generator, the ‘Human Dynamo bike’, provides exercise for the crew and also provides energy for the boat’s electrical systems.
The journey and aims
After setting off from San Francisco on March 20th, 2010, the six-man crew (including expedition leader de Rothschild) have explored many ecologically/environmentally important sites in the Pacific Ocean so as to provide more awareness on issues such as global warming and sea level rise (which poses a terrible threat to island nations), ocean acidification and damaged coral reefs, and marine pollution (especially by plastics). As of June 17th, they are south of Tuvalu and are en route for the final and most challenging leg towards Sidney, where the approximately 11,000-nautical mile expedition will conclude. So far, they have travelled for 90 days/2160 hours and 5785 nautical miles (and Plastiki helpfully adds that during this duration, 5400 million plastic bottles were used in the US alone!).
Plastiki’s mission is to raise awareness of environmental issues and the damage caused by ‘one-use culture’, and to enthuse individuals, communities, and businesses to find solutions to use waste as a valuable resource. Plastiki herself is an excellent example of how the discarded plastic bottles (usually meant to be a single use item, which we all use, and perhaps discard, everyday) can be utilised efficiently.
The plastic menace
Plastic is a huge menace (you may refer to my short summary on plastics and my longer essay on the effect of plastics in marine fauna in Our Gossamer Planet) since most are not biodegradable and takes a long time to degrade. Even then, these disintegrated minute pieces of plastic cause problems, most notably by leaching chemicals into the environment. It is estimated that out of approximately 100 million tonnes of plastic produced per annum, 10% ends up in the oceans- hardly surprising since 60-80% of total marine pollution is due to plastics (the UN had estimated that every square mile of the world’s ocean has approximately 46,000 minute floating pieces of plastic). But, the devastating effects of plastics in the ocean are no different from what happens on land: hundreds of thousands of marine fauna (including fishes, birds, turtles, and mammals) tends to mistakenly ingest these or gets entangled, resulting in death or poisoning. This, in turn, affects the biodiversity and the entire system.
Plastiki has also shed more light on the ‘garbage patch’, a subsurface sea of waste with mass of 3 ½ tonnes and about five times the size of the UK, floating in the North Pacific gyre between California and Hawaii. de Rothschild related of how Plastiki’s hull was covered with a fine, extra layer of plastic fragments. But more interestingly, the crew states that they have seen more plastic than fish during their journey so far, having caught three fishes and haven’t seen any sharks- a far cry from the Kon-Tiki expedition of Thor Heyerdahl, 40 years ago, when the crew caught fresh fish every day and could not enter the water fearing sharks.
Plastiki’s website is definitely worth visiting- with lots of interesting facts, photos, blogs, and videos, apart from live tracking and up-to-date information. MyPlastiki also allows visitors to make a pledge to better our oceans and planet by not using plastic bottles, bags, and styrene foams. The number of pledges, however, is quite disappointing - plastic bottles (1698 pledges), plastic bags (1589 pledges), styrene foams (1413 pledges), and all three (1143 pledges).
What we can do
But may be there is no need to be disappointed- each individual’s wholehearted actions can make a great effect, more so if the same is communicated to their peers and communities. Humans can exist by reducing or replacing (with ecofriendly alternatives) their usage of plastic bottles, plastic bags, and styrene foams (particularly the single use disposable types). One good method for an ecofriendly living is to follow the 4Rs- Reduce, Reuse, Recycle, and Rethink, and ultimately 2Rs- Replace and Refuse.
Wednesday, 16 June 2010
The 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
Saturday, 29 May 2010
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.
Saturday, 15 May 2010
Many people around the world are interested in rehabilitation of tropical forest, but despite this there is no real agreement on the best way to go about it. To look at some of the nitty gritty involved here is one detailed study that illustrates the problems (Jose Camargo et al, 2002, Rehabilitation of Degraded Areas of Central Amazonia Using Direct Sowing of Forest Tree Seeds, Restoration Ecology, 10, 636-644).
How does one make a forest?
The usual method in forestry is to plant seedlings, and this has been tried in forest reclamation, but it is expensive and time consuming, and not practical for large areas. Cheaper and easier would be use to use seeds, and they are also less susceptible to injury during planting by unskilled hands, but would they germinate? Part of the problem is the poor quality of the soil, made worse by poor agriculture. Also, which species? If you just want something growing there, one of the most successful on abandoned ex-forest land is Eucalyptus, but it is hardly a native flora. Renovating a temperate oak forest is relatively simple, just plant lots of oak (well ok, it´s a bit more than that), but the Amazon forest is characterised by an extreme diversity of plants, all in intense competition for very limited resources. Which to use?
Camargo and his team chose 11 native species, ranging from pioneer species to those of more established forest. This in itself is a problem, as the very number of Amazon trees means that most are not characterised yet. Also, some are dormant until they receive the right stimulus such as hot water or perforation.
They then chose four sites, intact forest, with trees about 20-30m tall, secondary forest dominated by shrubs and saplings of pioneer trees, up to 5m tall, abandoned pasture consisting of grasses and herbs, and, most hostile of all, bare earth from a highway project, compacted and stripped of top soil.
So, what happened?
After one year only one, the Piquia (Caryocar villosum), survived on all sites. The problems of a seed begin as soon as it hits the ground. Seed predation was high and seedlings suffered from fungi, predation and low light in the shade (germination was much higher on bare earth). Of the pioneer species, not one seedling was alive at any site after one year.
Caryocar villosum is a very large tree, 40-50 m tall. One reason for the success of the Piquia was it´s hard spiny shell defeating predation, whilst others suffered heavily. It also grew spectacularly fast, reaching 100 cm after just a year in some conditions, allowing it to escape shade very quickly.
The 2nd success was Parkia multijuga. P. multijuga has the advantage that it is a member of the legume family like peas and beans, and so, in effect, makes it´s own fertiliser. It´s therefore much less reliant than other trees on finding symbiotic mycorrhizal fungi in the soil, and in fact it actually renovates poor soil, adding nitrogen.
One of the surprises of this study was the failure of the pioneer species. These are plants that rely on producing huge numbers of very small seeds that drift on the wind, which spreads them over a huge area. This means that when new habitats become available they will usually be there ready, a big advantage. It might be expected therefore that these are exactly the trees to chose when starting a new forest. In contrast, it was those trees that produce huge seeds that more or less drop straight down and rely on animals to move them a little way from the truck, that survived. Why? Well the main benefits of the small seed/pioneer strategy are increased dispersal range and access to new germination sites, both of which are negated by direct planting. But also, the sheer hostility of the environment was unexpected. Large seeds are not a guarantee of success, as other studies have shown, but they do give the potential to grow fast escaping the shade of your rivals, and also the spare capacity to produce toxins, important when there are so many herbivores about. In the Amazon, any sort of ground cover harbours massive numbers of insects that chop up seedlings, one reason why germination was more successful on the bare, safe, earth.
In the end, out of 11 species tested, the authors could only recommend Caryocar villosum and Parkia multijuga for rehabilitation work, both non-pioneers with very large seeds. This is a still a big step forward, and gives a place to start.
There will be, hopefully, a lot of reforestation in the future. What this paper, and others like it, show is that it has to be done only after careful study, or a lot of effort will be wasted. There is a price to pay for the convenience and saving from avoiding nurseries and planting direct, and that price is paid by the plants. Without the care and protection of a nursery, life is very risky for seedlings.
Lastly, the long term future of any "new" forest has to be considered. For example the timber of Piquia is know to be excellent, and is used for housing and boats in the Amazon region. A forest mainly consisting of Piquia would be very tempting to loggers in the future.
Camargo, J., Ferraz, I., & Imakawa, A. (2002). Rehabilitation of Degraded Areas of Central Amazonia Using Direct Sowing of Forest Tree Seeds Restoration Ecology, 10 (4), 636-644 DOI: 10.1046/j.1526-100X.2002.01044.x
Friday, 7 May 2010
Saturday, 1 May 2010
The least movement is of importance to all nature. The entire ocean is affected by a pebble. Blaise Pascal
My original question was: ‘How can parents mold the environmentally responsible citizens of tomorrow?’, which was succeeded by discussions on Pets and on Like a Garden.
Now, this was not just a random query, but one of importance. These future citizens of tomorrow are those who, with their choices and attitudes, sculpt the earth of tomorrow regardless of whether or not they occupy key role in political governance. Thus, parents have crucial role to play, given the great degree of responsibility lying in these hands.
It would be inane to doggedly insist that mankind has not contributed to environmental degradation. The question which faces us now is about what can be done to rectify this degradation which mostly happened as a result of the race towards development. Whilst it might be hard to attain the state of the environment (before it was sullied), we can still, with proactive participation by each individual, prevent further deterioration, and if possible, try to restore some of what has been lost. This individual participation is decisive- very much like the general elections in your country. Each citizen is faced with two options- either to stay at home and choose not to vote for a myriad of reasons (usually it’s along the lines of ‘my vote doesn’t matter’) Or to participate in this and make their voices heard. That one little splash may generate a ripple which can have far reaching effects.
I would like to conclude this series, on Nature and Nurture, by enumerating a few more activities which would not only instill an awareness of nature and environmental issues, but also create a supportive attitude. None of these activities are restricted to your home- the same can be practiced at your school, university, workplace, or clubs.
a. The idiot box, that spring of all temptation and lethargy, is the unlikely hero, being the source of nature and wildlife channels such as Animal Planet, Discovery, and National Geographic, all of which air informative programmes on an array of areas pertaining to nature and the environment. Apart from broadening your horizons, these can provide a visual glimpse into the vast world beyond the confines of our cities and districts. And should one intend to pursue a career in the life and physical sciences, this early training would be useful.
Whilst it was only in 1996 that we subscribed to satellite TV and its extensive assortment of channels, our childhood featured us watching David Attenborough’s programmes and other wildlife documentaries, which have, doubtless, left a great mark upon us.
b. By opting for green technologies and energy supplies (including solar), one does more than doing their little bit for the environment. Another tip would be to make the maximum utilisation of natural sunlight – why switch on the lamps during daytime when the sun is much more luminous?
c. Recycling (as well as reducing unnecessary wastage) and Reusing could be encouraged. Furthermore, purchasing recycled materials, such as stationery, helps these green innovators and can also encourage the need to prevent harm to the environment. It is possible that you may already have such green initiatives in your town. If not, why not start these and encourage others to participate as well?
d. Reducing the amount of plastics used in the household. Also, a good shopping bag can easily accommodate all the groceries and reduce the usage of plastic bags which are so freely distributed by the retailers.
e. Instead of juicy gossips dominating the living room tête-à-tête, one could stimulate a fruitful and illuminating discussion by referring to environmental issues or discussing such recent reports.
f. A plethora of magazines are published the field of nature and the environment. For the novice, there are Birds and Bloom, Scientific American, and National Geographic. For the curious, New Scientist, Nature, and Science. For the professional, just too many to list down here. Reading these and adding these in your library or in the foyer can result in some amount of eye-opening!
g. Schools, universities, and workplaces have in-house magazines which certainly will be read by the current students/employees, the alumni, and (potentially) their family members. By publishing articles in these magazines, you will be reaching a wider audience. Encouraging the children to participate in such activities at their school will reap benefits as well.
h. And here’s one of my favourite activities: one often gets invited to birthday parties and many other occasions which requires celebrations. Why not give a plant (or some seeds) as a gift? Alternatively, you could gift them with a membership to a nature/environment organisation!
i. And why take the car when you can easily walk to a site/work/school? Good for health and good for the environment!
j. There are numerous other possibilities, but these require some degree of leaving the comfortable confines of your home and enjoying nature where it can be enjoyed best- the outdoors.
The possibilities are numerous: a visit to the zoo, weekend exploration of the countryside and nearby forests, ecotourism options, just to state a few. Furthermore, all of these can be garnished with hiking, biking, and (for the more adventurous) camping! And for those with tight purse-strings, these activities are all very affordable. After all, nature doesn’t come with a price tag.
I am very certain that I have overlooked other points relating to Nature and Nurture. If the readers have such suggestions, I will be very grateful if you could list them via the comments. I shall, then, incorporate these into another post. But WWF-India and AboutmyPlanet.com have a great list of tips for those who are interested in getting more tips on how to be green.
Parents tend to be the role-models of the children. Your behaviour and attitudes leave a lasting impact on them. So, if you tend to have a green outlook (although I would eschew anything too extreme!), it is likely that your children would be inspired to be like you as well.
And what do parents get out of this? Happiness, cohesiveness, and knowing that there’s one more environmentally responsible child, who, in turn, would inspire many others. After all, it is each individual choice which determines the nature of future policies. .
Friday, 23 April 2010
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,
the 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
Thursday, 15 April 2010
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
Friday, 2 April 2010
Consider logging, hunting and fire. Logging of tropical forests of course destroys habitat, but in those rare examples where it is controlled the loss of species is less than you might think, they often still persist in any remaining fragments. Hunting in pristine forest tends to hampered by difficulty of access, and large scale fire is relatively rare as the canopy keeps lower levels damp and hard to burn. However logging needs roads and this opens up previously inaccessible areas to hunters, as well the as the effect of loggers themselves. It is estimated that a single logging camp in Indonesia consumed 33,000 kg of bushmeat per year. Ease of access and increased demand together can devastate animal populations, particularly of large animals.
Logging also opens the forest canopy, drying out the undergrowth beneath, and greatly increasing the chance of fire. Most tropical forest plants lack the fire defences such thick bark or fireproof seeds of pampus species, and so are wiped out by fire.
Another example is the way that native species can be exposed to foreign pathogens imported by humans from elsewhere, a form of "pathogen pollution". Native species of have no, or very little, natural immunity to these diseases. As with the great human plagues of the middle ages, this can devastate whole populations. Animals in small habitats fragmented by logging or agriculture can be wiped out. To make matters worse, many diseases are exacerbated by "environmental stressors" such as pesticides, UV, and pollutants damaging the immune system
The world is a very very complicated place, events combine in unexpected ways, and the Law of Unexpected Consequences is as draconian as it ever was. We need to be aware of this in our thinking.
Friday, 26 March 2010
Saturday, 20 March 2010
provides evidence of the prevalence of a large scale of illegal ivory trade in Africa confirming that most of this continent lacks adequate controls for the protection of elephants. Equally the inability of the largest consumer nations mainly China and Japan to curb illegally traded ivory complicates the issue further. The paper argues a case against the petition to CITES by Tanzania and Zambia the largest sources and transit regions of illegal ivory for down-listing the conservation status of elephants for the one-off sale of stock piled ivory. The international group of authors are emphatic about disallowing such a sale which in their opinion which would promote illegal trade, split the appendix listing of the species and also sow discord among conservation workers.
The role protection agencies play in conservation of flora and fauna is undisputable. Enforcement of sensible and judicial rules and regulations promote species conservation. And as the paper aptly points out, policy enforcing organisations such a CITES will only satisfy its role with criteria that it puts science ahead of politics. Whilst the paper does offer valuable insight into the loopholes in legalities and law enforcement, it falls short of addressing some important issues. Firstly, it fails to offer any insight into to whether and how CITES can effectively curb illegal trade which based on its current record of ambiguous and confusing policies is difficult to buy into. Secondly, how can the petitioners nor indeed other African nations be convinced that selling the stock piled ivory is not the way forward. Having a set of rules is one thing, enforcing it is another. Therefore, ‘winning the hearts and minds’ of the policy enforcers in these nations is perhaps the biggest hurdle of all.
Friday, 12 March 2010
Here's some good news, although not that novel. But there has been so much of bad news relating to species decline globally that we need to remind ourselves that things might not be all that gloomy. Early last year, new species of amphibians were discovered in Ecuador & in Madagascar. In the case of the latter, many of these species were found outside of the conservation area. Discoveries such as these provides a glimmer of hope that somewhere in the deep depths of unspoilt or less spoilt rainforests are undiscovered species.This does not also exclude the possibility that a new species might be found in some nook and corner of the urban environment. Most importantly, such finding is a clarion call for us to raise environmental awareness and ensure that the habitat for these creatures are preserved. Also, next time you hear a croak, do give a second look, chances are highly unlikely that it might turn into a prince or princess as the case may; but if it does look unusual, photograph it and try to find out what species it is. Who knows you might be identifying a new species! For some reason that defies explanation, amphibians seem to be adapting or escaping from human onslaught on its environment.
If I have a favourite among the new species, it has got to be the 'glass frog'. Follow this link for a beautiful video from National Geographic
What links underwater volcanic springs,coral reefs & some researchers from Plymouth? Interestingly it is ocean acidification. There are an estimated 50,000 volcanic springs in the depths of the sea, which spew out carbon-di-oxide among other things into its surrounding. So what’s special about this you might ask. Well, the scientists from University of Plymouth have come up with an ingenious use for this naturally occurring phenomenon. They observed that water near the vents of these volcanoes is more acidic than the surrounding sea water, reaching to the predicted acidity level of oceans in three or four decades ,if ocean acidification due to anthropogenic activities is uncurtailed. This phenomenon therefore allows the use of these vents as labs on- the- sea for measuring the effect of ocean acidification on the growth of marine flora and fauna . As could be expected, the researchers found that the normally colourful sea bed often dotted with corals and sea urchins are replaced by sea grasses and invasive algae when waters become more acidic, an alarming reminder of what might happen if carbon-di-oxide emissions are left unchecked. The time is ripe for some action if we care about Nemo!
Wednesday, 10 March 2010
After collecting over 5000 samples of seawater, the scientists measured the levels of dissolved methane at varying depths. High methane concentrations were observed in more than 80% of deep water and more than 50% of surface water samples, with most having concentrations more than eight times the normal amount in the Arctic Ocean. Analysing the air directly above the water surface and at higher elevations confirmed their findings. The team calculated that the region is releasing about 7 teragrams per annum (1 teragram is approximately 1.1 million tonnes), which is equal to the amount of methane emitted from the oceans (about 2% of the overall methane emissions to the atmosphere). As a result, more than 100 hotspots were located where methane is leaking from the sub-sea permafrost, which is believed to generally act as a lid to contain the methane reservoir.
When the earth becomes warm, warmer seawater enters the area. If and when the permafrost thaws, the stored frozen methane is released in two ways: Firstly, the stored organic material (ESAS, being shallow and averaging around 50 meters in depth, would have been submerged or terrestrial over the millennia) decomposes and gradually releases methane. Secondly, methane gas or methane hydrates could be released. Although methane usually oxidises into carbon dioxide before reaching the surface of deeper waters, it escapes to the atmosphere in the shallow ESAS.
The current average methane concentrations in the Arctic is around 1.85 ppm (which is the highest in 40,000 years), with much higher concentrations in ESAS- very alarming when considering that the Earth’s geological record indicates that atmospheric methane concentrations are between 0.3 to 0.4 ppm (during cold periods) and 0.6 to 0.7 ppm (during warm periods). As pointed out by Martin Heimann in his perspective in ‘Climate Change: How Stable Is the Methane Cycle?’ (in the same edition of Science), more warming in the Arctic, implies more destablisation of the permafrost, which implies more release of methane and the creation of ‘a positive feedback loop that amplifies global warming’.
Despite the current controversies in the field and the increased scepticisim about the effects of climate change, these findings might have heavy implications. A caveat is the vagueness over whether this is a new phenomenon or whether it is a constant natural phenomenon. What are the precise factors behind this? Will there be further larger release of methane? Will global warming accelerate this release? What would happen in such a scenario? Would it result in a rapid and devastating climate change, as predicted?
Friday, 26 February 2010
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
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