Marine phytoplankton – the tiny, single-celled algae, which act as a natural sponge for carbon dioxide and are a critical part of the global carbon cycle – may play a key role in ensuring the health of the planet, say a Canadian scientist.
According to Maria (Maite) Maldonado, Canada Research Chair in Phytoplankton Trace Metal Physiology at The University of British Columbia, phytoplankton form the base of the ocean food chain, have an integral role in controlling global warming and provide more than half of our oxygen supply.
Each year, phytoplankton are responsible for converting about 45 gigatons of carbon dioxide from the atmosphere to organic carbon. Of this, approximately 16 gigatons is transferred to the waters of the deep ocean in a process commonly referred to as a “biological carbon pump.”
The deep ocean is one of the Earth’s natural carbon “sinks” and will hold carbon from the atmosphere for centuries. The biological carbon pump controls the carbon dioxide content in the upper ocean, which in turn regulates atmospheric carbon dioxide levels—and, as a result, climate change.
Scientists have established that low iron concentrations in ocean water limit phytoplankton growth, since phytoplankton use iron to photosynthesize and grow. In these iron-limited environments (which make up approximately 30 per cent of the global ocean), the biological pump becomes inefficient and the ocean’s ability to absorb carbon dioxide from the atmosphere is reduced.
