Print PageEcosystem scientists tend to equate importance with high net primary productivity, so much attention is focused on tropical forests and the upwelling zones of the global ocean. But, low productivity systems—in polar regions and subtropical deserts—leave a critical imprint on the Earth’s biogeochemistry. Hot dry deserts are the source of most of the continental dusts in the Earth’s atmosphere. These supply the oceans with Fe, P, Si, and other trace nutrients that sustain new production in the sea. Iron deposition in the Southern Ocean fuels its NPP and the release of dimethylsulfide to the atmosphere. Indeed, the waters of the Southern Ocean surrounding Antarctica are the source of most of the dimethylsulfide that enters Earth’s atmosphere. If we are to have a Gaia-type feedback to the ongoing global warming of the planet, dimethylsulfide is likely to be it.
Results/Conclusions
Ongoing changes in the Arctic have profound implications for accelerating climate change—decreasing albedo with the loss of sea ice, increasing carbon dioxide releases from a huge pool of decaying peat, and the potential for a catastrophic release of methane from sedimentary clathrates. Each of these could all carry planet Earth beyond a threshold of likely recovery from climate change.
