The marine food chain
Marine biologists know that the marine food chain is particularly complex and sensitive to the distribution and duration of the ice cap. Accordingly, Danish research scientist Professor Torkel Gissel Nielsen of The National Environmental Research Institute, NERI, working with other researchers, has developed a model to calculate how the food chain is affected by temperature rises.
If the water flea goes hungry
The model indicates that one winter without heavy frost, and thus without an ice cap, could damage fish stocks for the next few years.
For example, the water flea plays a key role in Greenland’s fjords as food for fish larvae, and thus as a base for the food chain that has polar bears and seals at the top. The water flea rises to the surface from hibernation in April and lives mainly on algae. However, when the ice is no longer there to keep the light out, the algae blooms as early as March. Single-cell types of phytoplankton immediately begin to consume the algae. Therefore, the water fleas have to make do with a less varied diet of single-cell organisms. This reduces the number of water fleas, meaning there is less food for the fish larvae.
The models can help people to adapt to climate change. “Once we know how the food chain is affected by temperature changes, fishing can be managed sustainably and can thus retain its significance for the people of Greenland,” Torkel Gissel Nielsen tells DMU-Nyt, no. 1. Torkel also believes the fauna will adapt to the changes.
However, it is difficult to say with any certainty what climate change means in terms of the food chain in the longer term. Some take a positive view and hope it may mean a change in the combinations of species; for example, after an absence of 30 years, cod may make its way back into Greenland’s waters.