Rijpfjorden Research Hut (Photo credit: Janne Søreide)
At first glance the Arctic Ocean appears to be a biologically diverse area. Whales, sea birds and a myriad of species of fish all live in this pristine wild environment. Take a closer look and you discover that this diversity is reliant on 1 species, the zoo-plankton Calanus glacialis.
Calanus glacialis is important to the regions food web as it is a high value nutritious organism that is packed with the all important omega 3 oils. the zoo-plankton provides food directly to organisms such as whales and fish and indirectly to most of the creatures found in the Arctic. For example fish feed on the zoo-plankton, seals feed on the fish and polar bears feed on the seals. At the base of it all are the minute krill like creatures Calanus glacialis.
Understanding the impacts of climate changer and nutrient flow in the Arctic.
Now a new Norwegian led project called Cleopatra is looking at the impacts of climate change on Calanus glacialis. The life of this small marine creature is closely aligned with the availability of algae and phytoplankton which in turn is closely related to the melting of sea ice. Changes in melting patterns of the Arctic ice-fields could have impacts all the way to the top of the food chain.
The first part of the project – led by the Research Council of Norway – has been looking at the current relationships between the zooplankton and the alga and phytoplankton. The life cycle of the Calanus is in perfect harmony with major blooms that occur under the ice.
2 major blooms underpin the food web of the Arctic Ocean.
The first bloom of algae that lives attached to the underside of sea ice feeds the female Calanus and helps the development of eggs. This bloom usually occurs in April as the sea ice begins to melt and thin. The increased ability of the spring sun to penetrate through the ice fuels the growth of the algae.
The next major bloom occurs in July after the sea ice has melted completely. This time it’s the turn of the phytoplankton to take advantage of increased sunlight. Calanus has timed it’s birthing period so it’s offspring is large enough to feed on this bloom and there is ample food and nutrients to feed the new population.
“In the Arctic Marginal Ice Zones, the ocean is covered with ice in the winter. When the ice finally releases its grip with the advent of Arctic springtime, an explosive production of biomass occurs,” explains Jørgen Berge, a professor of biology at UNIS and Cleopatra project manager.
Calanus glacialis – the important base of the food chain.
Because Calanus glacialis is such an important part of the food chain, it really does feed almost every creature found in the Arctic Ocean region, any threats to it’s survival will have serious implications for the biodiversity of the region as a whole.
The major concerns with climate change is if the sea ice thins too rapidly and too much in April. Too much sunshine is known to kill the algae or prevent it from producing large amounts of the omega 3 oils. If the female Calanus are faced with nutrient shortages this could reduce the reproductive abilties.
The other major concern is with sea ice melting too soon leading to the phytoplankton bloom occuring to early to be of benefit to the juvenile Calanus. This could lead to large scale starvation and loss of young zooplankton as they arrive too late to take advantage of the phytoplankton bloom.
