Global warming ‘affecting food chain, carbon cycling in Arctic Ocean’

March 3rd, 2011 - 4:43 pm ICT by ANI  

Washington, Mar 3 (ANI): Over the past decade, the annual bloom of phytoplankton in the Arctic Ocean has been arriving earlier each year - a change that could hurt the marine food chain and carbon cycling in the region, according to a new research.

Scientists from the Scripps Institution of Oceanography (UC San Diego), Mexico and Portugal have attributed the shift to warming temperatures and melting ice in the Arctic.

Using satellite data from 1997-2010 depicting ocean colour and phytoplankton production, they found that the spring blooms have been arriving up to 50 days earlier in some areas over this 10-year period.

The researchers said the earlier Arctic blooms have roughly occurred in areas where ice concentrations have dwindled, creating gaps where the bloom can briefly flourish.

During the one to two week spring bloom, which occurs in warm as well as cold regions, a major influx of new organic carbon enters the marine ecosystem through a massive peak in phytoplankton photosynthesis, which converts carbon dioxide into organic matter as part of the global carbon cycle.

Phytoplankton blooms stimulate production of zooplankton, microscopic marine animals, which become a food source for fish.

“The bloom provides a major source of food for zooplankton, fish and bottom-dwelling animals. The advancement of the bloom time may have consequences for the Arctic ecosystem.”

Mati Kahru, lead author and a research oceanographer at Scripps, said that it was not clear if fish will adapt to match the change, and whether it would disrupt their critical life-cycle stages such as egg hatching and larvae development.

“The spring bloom provides a major source of food for zooplankton, fish and bottom-dwelling animals. The advancement of the bloom time may have consequences for the Arctic ecosystem,” he said.

Such a match or mismatch in timing could explain much of the annual variability of fish stocks in the region.

“The trend towards earlier phytoplankton blooms can expand into other areas of the Arctic Ocean and impact the whole food chain,” the researchers concluded.

The findings will appear in the March 9 edition of the journal Global Change Biology. (ANI)

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