Decreased populations of krill affect the entire antarctic food chain as well as commercial fishers who harvest them. Valerie Loeb from Moss Landing Marine Laboratory in California worked with American and German colleagues to study the effect of fluctuating winter temperatures on the population of krill in the area around Elephant Island, just off the tip of the Antarctic Peninsula. Loeb and her fellow researchers found that, compared with counts done a decade ago, krill populations had decreased by a factor of 10. Even human fishers harvest the krill to be cooked and peeled and made into sausage, fish paste, or livestock feed. Because krill are so vital to the entire antarctic food chain, scientists are monitoring the natural fluctuations in krill populations as well as the impact of commercial harvesting.
Krill compete for algae with gelatinous creatures called salps .
When there are fewer algae to go around, the competition is keen. Other marine biologists believe that the increased salp blooms may not curb krill populations. Robin Ross, a biological oceanographer from the University of California's Santa Barbara Marine Science Institute, notes that migration should be factored into the equation. This influx of warmer water causes melting of this ice base. The reduced volume of the warmer water means a reduced influx of heat to the base of the ice shelf, so the ice thickens.