18 June 2010 | Luca Del Buono
Biodiversity, Climate Change, Water, Europe

 

A rise in ocean temperatures as a result of global warming and climate change is affecting biodiversity worldwide. One example of this is occurring in the North Sea off the coast of Britain's east coast. Henslow swimming crabs from Portugal have migrated to the UK as a result of the rise in water temperature.

Over the last 30 years it has been documented that the North Sea has become warmer, Dr Richard Kirby, a Royal Society Research Fellow at the University of Plymouth claims that, "The North Sea is now 1 degree C warmer than it was 30 years ago." This warmth has attracted an influx of the Henslow crab. A recently published work in the Proceedings of the National Academy of Sciences has observed that 84% of global warming occurs in oceans.

Unlike many crabs, which remain on the seabed, the Henslow crab is an active hunter due to its ability to swim. Dr Kirby believes that this trait along with the abundance of prey in the North Sea has attracted the crabs:

"What we have now shown is that a component of the changing abundance of decapod larvae in the plankton is the presence of new warm water species such as Henslow's swimming crab Polybius henslowii and the angular crab Goneplax rhomboides."

The influx of new species such as the Henslow crab could have a major effect on the food chains and the biodiversity of the North Sea. Crabs are a vital predator on the seabed where they feed on animals such as shellfish, keeping equilibrium in the food chain. With the introduction of a new predator it is unknown how this balance will be upset. Dr Kirby has noted that:

"Crabs and shrimps are important predators and their prey includes bivalves and young flatfish. Coincident with the increase in crabs and shrimps the abundance of bivalves and young flatfish has declined."

The change in climate and ocean temperatures is creating a whole new ecosystem in the North Sea. Predictions that seas will continue to warm could mean that this ecosystem will continue to change as more species could migrate into the area. The existing biodiversity of the North Sea is at threat as water temperature rises and foreign species invade the current ecosystems that are in place.

 

Author: Rachael Bristow | Climate Action

Image: Acheron333 | Flickr

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