photo: Seth Lieberman via flickr.
What an interesting intersection of biology and geo-engineering: Our colleagues over at Discovery News are pointing out that because the amount of extra iron sperm whales bring up from the ocean depth when the feed they stimulate enough carbon-trapping plankton growth to effectively be considered a carbon sink: Sperm Whales Net 5 Million Ton Carbon Reduction
Sperm whales once had a reputation of breathing out so much CO2 that it contributed to global warming. However not only is that not the case but analysis by Trish Lavery of Adelaide, Australia's Flinders University shows that the activities of the world's sperm whales could be capturing up to a net 5 million metric tons of carbon from the atmosphere annually.
Sperm whales, however, feed by diving for squid in the cold depths of the Southern Ocean. This zone normally acts as deep storage for nutrients, Lavery says. So anything the whales bring up effectively introduces something new to the upper waters.
Skimpy levels of iron in the Southern Ocean limit growth of the floating meadows of plankton there, Lavery says. This limitation has inspired human experiments in adding iron to trigger a big plankton bloom. A burst of iron-fed organisms would draw in carbon dioxide and then trap some of it as a portion of the bloom dies and sinks into deep cold storage.
Get the full story: Discovery News
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