Ocean Sentry
(From environmental-expert.com) EU –Climate change is predicted to have large-scale impacts on biodiversity. Although organisms adapt to their environment, if conditions shift rapidly, populations may not be able to respond in the short-term and may decline. If ocean climate changes are large and if the depletion of top-level fish continues, there are likely to be large scale negative consequences for seabirds, fish and whales and the Arctic and sub-Artic communities that depend on them. A recent study has looked at how changes in sea temperature in the past influenced the size of two seabird colonies in the circumpolar region of the North Pacific and North Atlantic. The findings provide clues as to how ecosystems could be affected under a future changing climate. The reaction in colony size to climate change showed that the birds were sensitive to abrupt changes in their environment. The reasons for the drops in population size are likely to be related to a decrease in prey as a result of SST change. Prey species include cod, sculpins, capelin, herring and sandlance. Fish populations are known to be sensitive to regime shifts and long term climate changes and changes in populations of fish-eating seabirds are likely to be closely linked to changes in their prey-base.
The two related murre species reacted differently to small changes. A slight shift to warmer seas favoured the Artic Thick-billed Murres, which were able to forage more successfully as ice-bound waters melted. Slightly cooler seas on the other hand favoured the temperate Common Murres which feed on fish in cold, energy-rich waters. For both species, large rapid changes had a negative impact on numbers irrespective of the direction of the shift. However, the decline of the Thick-billed Murres was greater when temperatures cooled, and the decline of the Common Murres was greater during warming.
(source: European Commission, Environment DG)
