The Ecology of Whale Shit

Edward Hopper, Rooms by the sea (1951)

Big bloody animals, the whales. Exhale a lot of Co2, the buggers, leaving their huge eco-footprints all over the ocean wastes. Should be more on the menu, as in Japan, Iceland, Norway.

Wrong. Their shit puts their carbon account overwhelmingly in the black (unlike ours). Forget your energy-intensive, hi-tech wet dreams, it is whales that are the ultimate geo-engineers of carbon sequestration. Here’s how it works, a lesson in Ecology 101. [1]

Whale shit is rich in iron. The estimated 12,000 sperm whales left in the Southern Ocean alone excrete about 50 tonnes of iron each year in the iron-poor surface waters. This iron stimulates the growth of phytoplankton. These microscopic plants in turn soak up a lot of CO2. When they die, the embodied carbon sinks with them to the deep ocean. Bingo, about 400,000 tonnes of carbon are thus sequestered each year by the Southern sperm whales alone. They only make up about 3% of the global population, so the total amount of carbon sequestration by whales could be quite significant.

The bad news is that industrial culling of sperm whales globally has resulted in an estimated extra 2 million tonnes of CO2 a year remaining in the atmosphere. In addition to all the other arguments, banning whaling is also necessary to reduce global heating.

Other whales around the West Antarctic are also feeling the heat, as it were.[2]  Their food sources are shrinking. Phytoplankton has declined by 12 % over the last thirty years and also shrunk in cell size. This allows populations of jellyfish-like creatures called salps to increase because they find it easier to feed on the small phytoplankton cells. Salps are outcompeting the krill which also eat phytoplankton and which provide the main food source for the whales. Salps also eat the eggs and larvae of krill.

The oceans and their billions of diverse and beautiful creatures are the heart and lungs of our planet. They produce about half of the oxygen we breathe and absorb about a third of our carbon emissions. Like many human hearts and lungs, this oceanic heart and these oceanic lungs are beginning to fail. Warmer water, changes in circulation patterns, pollution and acidification due to our carbon emissions are destroying corals, sea grasses, salt marshes, oysters and mangroves, vital habitats on which hundreds of thousands of species and many millions of humans depend.

With capitalist business as usual, we are heading towards dead, toxic ocean soups. Save the whales, save the oceans, save humanity. I would humbly submit this means replacing capitalism with a system based not on profit but on the basic needs of the planet and its people.

[1] Figures are from D. Smith, ‘Whales give carbon a bum steer’, SMH 17/6/2010, p. 5.

[2] Figures from D. Smith, ‘Sydney today. Gone tomorrow?’ SMH 18/6/2010, p. 1.


~ by Peter Lach-Newinsky on June 30, 2010.

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