Barely longer than your thumb, weighing under an ounce and nearly translucent, delicate crustaceans known as krill are vital to ocean ecosystems around the world. In the waters that encircle Antarctica, krill are an essential food source for penguins, baleen and blue whales (which can eat as much as 4 tons of krill per day), fish, seabirds, and other marine creatures. The health of these Southern Ocean species depends heavily on healthy krill populations. But Antarctic krill are also increasingly sought after as a source of food for farmed seafood, livestock and poultry. And although you probably won’t find krill on the menu anytime soon, their omega-3 fatty acids and other nutrients have made them popular for human consumption in the form of krill oil. Since 2010 the world catch of Antarctic krill has grown by about 40 percent. While tiny, krill are considered one of the most abundant species in the world; their combined biomass is estimated to exceed that of all the people on the planet. But even though the supply of krill would seem inexhaustible, scientists are concerned what the combination of fishing and climate change (including ocean acidification) means for Antarctic krill and, in turn, for the entire Antarctic marine ecosystem. In many ways, these tiny crustaceans are becoming a key factor in thinking about what we choose to eat in a high CO2 world.For at the same time krill fishing has increased, krill habitat has been disappearing as the Southern Ocean warms — more rapidly than previously thought ­and faster than any other ocean. Krill need both sea ice and cold water. Rising temperatures reduce the growth and abundance of plankton on which krill feed, while loss of sea ice removes habitat that shelters both krill and the organisms they eat. So when Antarctic sea ice declines, so do krill. One recent study suggests that if current warming and increasing CO2 trends continue, Antarctic krill could lose at least 20 percent — and in some, particularly vulnerable locations, as much as 55 percent — of their habitat by the end of the century. The nutrients … Continue reading Does one of the world’s most abundant animals need protection from our appetite?