Goan to Antarctica....

Goan scientist Helga do Rosario Gomes is en route to the icy continent, and is keeping her blog of the journey...

Sunday, November 27, 2005

And you thought science was fun?

In search of greener pastures, we bulldoze through sheets and sheets of the thickest of ice... aided by ocean color satellite data that NASA sends us daily. We finally arrived at the perfect spot.

Sufficient phytoplankton to work with and pleasant temperatures that are kind to our incubators.

By the way, ocean color remote sensing, my other field of interest, provides us with daily maps of concentrations of phytoplankton in the world's oceans based on the amount of light that falls on the water and that is absorbed by phytoplankton.

We now start our experiments, so I guess a small description of our work is in order.

Phytoplankton, like terrestrial plants, are the only organisms that can photosynthesize or make their own food -- meaning that they can use carbon dioxide available in plenty both in the air and in water, sunlight and nutrients such as phosphate and nitrate to grow very quickly.

The rest of the food chain depends on the food produced by them.

The Southern Ocean which forms part of the Antarctic continent has plentiful of nutrients but its only in spring that light levels are adequate for photosynthesis to occur. When this happens massive blooms of phytoplankton occur all over the Southern ocean and provide a smorgasbord for the rest of the food chain.

In the early 'eighties, British scientists discovered that a suite of chemical compounds, the Chloro Fluoro chemicals (CFCs), then considered as 'wonder chemicals' because they did not react with anything, were in fact piling up in the stratosphere and breaking down the ozone layer that blankets our planet.

The ozone layer protects us from the sun's harmful radiation -- the Ultraviolet radiation. They observed and even won a Nobel for their work that every spring an increasingly larger ozone hole was developing in the Antarctic with a consequent increase in Ultraviolet light falling on the earth's surface, especially in the Southern hemisphere.

The Montreal Protocal banned the use of CFCs, but their damage still persists because they are very hard to get rid of and consequently every year the ozone hole increases over the Antarctic.

Check this site for ozone holes at http://ozonewatch.gsfc.nasa.gov It looms over us as I write this but, of course, I am not sitting on the deck with my laptop because I would die from the cold before the ultraviolet light got my DNA!!!

How this ultraviolet light impacts the marine life especially phytoplankton which form the basis of the food chain is the thrust of our program named MIXURS, or "Mixing and Ultraviolet Light in the Ross Sea."

Phytoplankton have no motion of their own so they depend on waves and other turbulence to keep them in the upper portion of the water column where there is light. But here is the Catch-22 for in positioning themselves in well lit zone, they are also vulnerable to DNA damage from ultraviolet light.

What kind of waves and turbulence is the upper well lit water column influenced by? Are they on time scales that allow phytoplankton to stay and photosynthesize without damage to their DNA?

Can they manage to repair the damage through built in mechanisms? If they are damaged what kind of damage is it and to which processes? These are some of the questions that we will try to answer on this third cruise in a series of three.

Photo above shows an ozone hole image for the earlier part of November over the Antarctic continent. The darker blue and purples are regions where the ozone layer is very thin.More information on the ozone hole can be found at http://ozonewatch.gsfc.nasa.gov/


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