Copepod is “keystone Arctic species” as indicator of climate change

In an article in the October 2014 edition, The National Geographic reports on Franz Josef Land in the Arctic Circle. This archipelago of islands is a nature reserve under Russian law and host to a wide range of Arctic animal species, in particular, the little auk.

Little auk

Little auk
Photo: Hallvard Strøm / Norwegian Polar Institute

The National Geographic reports: “The little auk feeds primarily on copepodscopepods A group of small crustaceans found in the sea and nearly every fresh water habitat. Some species are planktonic (drifting in sea waters), some are benthic (living on the ocean floor), and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds and puddles, damp moss, or water-filled recesses (phytotelmata) of plants such as bromeliads and pitcher plants. Many live underground in marine and freshwater caves, sinkholes, or stream beds. Copepods are sometimes used as biodiversity indicators., minuscule crustaceans that are the main component of Arctic zooplanktonzooplankton Zooplankton form the group of tiny animals such as minuscule jellyfish and rotifers present in the marine environment. They are a major source of food for those higher up the food chain, and their numbers relate directly as a good indicator to the nutrient enrichment of the sea of the area. Note: phytoplankton are microscopic plants, and zooplankton are microscopic animals.. Each bird needs to gobble thousands of them to make a square meal. “And these copepods, they have very specific temperature preferences,” Grémillet explains. “So you can predict that if these copepodcopepods A group of small crustaceans found in the sea and nearly every fresh water habitat. Some species are planktonic (drifting in sea waters), some are benthic (living on the ocean floor), and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds and puddles, damp moss, or water-filled recesses (phytotelmata) of plants such as bromeliads and pitcher plants. Many live underground in marine and freshwater caves, sinkholes, or stream beds. Copepods are sometimes used as biodiversity indicators. communities change because of climate change in the Arctic, the little auks will show a strong response.”

How might the copepod faunafauna The animals characteristic of a region, period, or special environment change? One of the larger and fatter kinds, Calanus glacialis, depends upon very cold water and the presence of sea ice, beneath which grow the algae that it eats. A smaller and leaner species, Calanus finmarchicus, is common in the North Atlantic and often rides currents into the Arctic but doesn’t flourish there.

Photo: EOL (Encyclopaedia of Life)

Photo: EOL (Encyclopaedia of Life)

As the Arctic Ocean warms by a few degrees, though, the competitive balance could shift. Higher temperatures and decreases in sea ice could allow the small, lean copepods to replace the big, fat ones, to the detriment of the little auk — and of other creatures as well. Arctic cod, herring, and various seabirds feed on the copepods, and even such mammals as ringed seals and beluga whales depend on fish that feed on them. That’s why scientists consider Calanus glacialis a keystone species in the Arctic.

Source: The National Geographic, October 2014. For the full text see http://ngm.nationalgeographic.com/2014/08/franz-josef-land/quammen-text

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