Dust tales

It is well past Earth Day. Some of us did our bit, some forgot in the bustle of everyday life. But here is something again that reminds us how connected we all stand (and we are not speaking spiritually as Dan Brown does in The Lost Symbol!) This is the ecological web of life we are talking here.

Have a look at the picture first. Is it just another shot of our home planet? Look again. See the dust trail? Dust from the Sahara Desert – the world’s largest desert, encompassing around 8.6 million sq km – can be transported over thousands of kilometres by atmospheric convection currents. These convection currents form when warm, lighter air rises and cold, heavier air sinks.

Sandstorms are very common over the Sahara, and large concentrations of the dust can be found in the tropical Atlantic and the Caribbean. The dust contains many nutrients, including nitrogen, phosphorus and iron, which act as a fertiliser and stimulate the production of massive plankton blooms.

Planktons are microscopic marine plants that drift on or near the surface of the sea and are the basic food on which all other marine life depends. They contain chlorophyll pigments and are able to convert inorganic compounds, such as water, nitrogen and carbon, into complex organic materials.

With their ability to 'digest' these compounds, they remove as much carbon dioxide from the atmosphere as terrestrial plants. As a result, the oceans have a profound influence on climate. Since plankton influence the amount of carbon in the atmosphere, it is important to monitor and model them into calculations of future climate change.

Did you ever spare a thought to a plankton? Do you now agree they are important in the scheme of life? Did you ever realise how connected we are to the remote regions of our planet, thanks to its dynamics? Next time you swear at dust, just stop and think. Where did it come from?!