Friday, 26 February 2010

Sunlight on the sea

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

Sunday, 21 February 2010

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

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)

Fabry VJ, Science 320 (2008)

(PS- The topic of mismanagement of oceans was touched upon in a previous blog 'Ten Years Hence' By David Buss

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

Tuesday, 16 February 2010

Paper of the Week: The link between snowfall increase in Antarctica and drought in southwest Western Australia

Tas van Ommen and Vin Morgan, of the Australian Antarctic Division, published a paper "Snowfall increase in coastal East Antarctica linked with southwest Western Australian drought" in Nature Geosciences. Turns out that this region of Australia has been facing a 40-year drought which was attributed to several factors, such as ‘natural variability, changes in land use, ocean temperatures and atmospheric circulation’. After evaluating the precipitation records of the two regions (East Antarctica and southwest Western Australia), the authors report an inverse correlation, surmising that the rain which should have fallen in Australia may have moved to Antarctica, resulting in heavy snowfall. What needs to be evaluated is whether this is purely due to anthropogenic climate change and whether the study can be substantiated by constructing similar correlations in other southern hemisphere nations which also has/had similar conditions of drought. van Ommen, T., & Morgan, V. (2010). Snowfall increase in coastal East Antarctica linked with southwest Western Australian drought, Nature Geoscience, 3 (4), 267-272

Friday, 12 February 2010

Nature and Nurture: Like a Garden

Come forth into the light of things,
Let nature be your teacher.
- William Wordsworth

An oft-used metaphor compares children to sensitive plants in a garden. Each plant has its own specific requirements for its optimal growth, and it’s a wise gardener’s forte to ensure that the plants flourish.

My aim is not to elaborate on the above, but to point out how children’s participation in gardening can instill a deeper appreciation for nature and the environment (activities which can be followed by anyone!).

Perhaps a few readers might roll their eyes considering it to be unfeasible, given that they reside in a 500 sq ft apartment. Of course, although we might be more than happy to visualise a garden of some acres (complete with lawns, mazes, hedges, ponds, gazebos, and greenhouses), a miniature garden can be created in your own apartment, or even inside your own room! A particularly industrious acquaintance at Keble College once maintained a miniature garden of herbs on the small round table in his college room! Thus, the possibilities are many: the balcony/porch, the loo, or even the kitchen’s window sill. In fact, perhaps it is more sensible to grow plants indoors in temperate countries, such as UK, given the harshness of autumn and winter seasons!

Now that we have identified sites to have a (miniature) garden, children could be encouraged to take part in cultivating flowering plants, as well as vegetables. The latter might provide more perceptible utility, given that it could end up on the dining table!

Another activity would be to identify plants, and, if possible, to maintain a herbarium or scrap book with all the information. Apart from providing practical experience, supplementary to the theoretical coursework at school, gardening can instill a love for nature and environment and proactive attitude towards its preservation. Needless to say, it is tough to quantify the aesthetic utility and happiness which one derives from enjoying the garden and when participating in gardening.

Beth Shalom, as Ruth mentioned, is a true hotchpotch of all kinds of trees, shrubs, and herbs, a cumulative result of our father’s background in Botany. Not only are our neighbours very less enthusiastic about this (citing that the leaves from our trees litter their grounds and that our vegetation harbour dangerous animals which are determined to dispatch them off), many a ‘well-wisher’ have advised clearing away all plants and fit concrete/tiles around the house (as is the norm). Houses with a profusion of plants are tagged as ‘haunted’ and ‘cursed’, since the inevitable shade is associated with evil. There are also the practical problems of clogging up the drainpipes and the creepy crawlies which seek either to nestle under fallen leaves or to pay a personal visit to your room. Inevitably, our mother often succumbed to these ‘practical wisdom’, and thus a few plants were hewn down.

Yet, there were so many instances in which we were encouraged to appreciate plants. Our father would demonstrate how to make sections of plants and would show us the cross-sections of leaves, roots, and stems under our microscope. Mitosis was another interesting demonstration. Existing mature trees supplied tamarind, varieties of jackfruits and mangoes, not to mention coconuts (the Kera of Kerala)! There were also other shrubs such as mulberry, cherries, and gooseberry. We (the kids) also used to harvest arecanut, pepper, and coffee. Often we attempted to cultivate organic vegetables: whilst some efforts were successful, it would be a tad disappointing when the so-labelled tomato seed germinated into chilli plants!

If you indeed have a few sq ft, or cents, or acres, why not grow plants and increase the biodiversity of the area? For where flora is, fauna will follow.

Wednesday, 10 February 2010

Save Our Tigers

The Save Our Tigers is a collaborative campaign run by Aircel and WWF-India.

I recently came across their poignant advert (
which you can view here).

With the Chinese New Year (interestingly, of the Tiger!) barely 3 days away, tigers have been placed on WWF’s list of ten critically important endangered species facing extinction. There are only 3200 tigers left in this world (a reduction of 95%), spread over the subspecies of the Amur, Bengal, Indochinese, Malayan, and Sumatran tigers. Three subspecies (viz. Bali, Caspian, and Javan tigers) are now extinct, and the South China tiger have not been sighted for the past 25 years.

In India, from an estimated 40,000 tigers a century ago, only 1411 tigers remain in the wild (according to a study conducted by the Wildlife Institute of India, in association with NTCA, Government of India, 2008). The Bengal tigers (the national animal of India) have, unfortunately, become an easy victim to the avaricious and callous man. It was cruelly hunted during the colonial times and its parts are now used in certain indigenous/traditional Asian medicine.

Please, let not our descendants read about the tigers like we now read about the dodo.

register your support and do the spread the word to your friends and acquaintances as well. You can also join the Facebook page or tweet @saveourtigers

Saturday, 6 February 2010

Ten Years Hence...

Our esteemed editor has asked me to contribute a few thoughts on the way the environment might change in the next ten years.

I suppose the first thought that enters my head is that, in many ways, where we are now is better than any time in the last 150 years, at least in industrialised countries. Rivers are cleaner and the air is purer. This has perhaps given a false sense of confidence.

The "problem" with global warming is that it is not a readily perceived threat. An approaching asteroid, for example, could be shown on tv and everybody would understand. Climate change however is more nebulous, especially after the winter Europe is experiencing. It needs to be taken on trust, and when that trust is apparently abused to raise taxes or commodity prices, people become cynical. It will indeed be very interesting to see what happens in this area in the next 10 years.

So, should I make a prediction for the next Big Thing over this decade? Frankly, only a fool would attempt to see that far into the future, so here goes. We've cleaned up the environment around us, we're starting to address changes in the atmosphere, but one area is nicely out of sight - the ocean. This has already been touched on by sann2282. For centuries everything we pour into our sewers or rivers has ended up here, not to mention the dumping of solid waste. As pressure on landfill sites increases, the later is likely to increase. Cleaning rivers is easy, you just stop adding junk, and what's there flows away, but rubbish in the ocean has nowhere to go. Of course it is very, very, big, and degradation does takes place. But so does concentration, as has been seen in the Sargasso sea and the Pacific Trash Vortex. Eventually we will have to address this.


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