Global Warming

Global warming doubles growth rates of Antarctic seabed's marine fauna – study

Marine life on the Antarctic seabed is likely to be far more affected by global warming than previously thought, say scientists who have conducted the most sophisticated study to date of heating impacts in the species-rich environment.

Growth rates of some fauna doubled – including colonising moss animals and undersea worms – following a 1C increase in temperature, making them more dominant, pushing out other species and reducing overall levels of biodiversity, according to the study published on Thursday in Current Biology.

The researchers who conducted the nine-month experiment in the Bellingshuan Sea say this could have alarming implications for marine life across the globe as temperatures rise over the coming decades as a result of manmade greenhouse gases in the atmosphere.

Sub-zero conditions near the south pole mean there are comparatively few species on the usually frozen land, but below the ice, the relative lack of pollution, traffic and fishing has left an abundance of marine life that divers and biologists compare to coral reefs.

Twelve identical 15cm sq heat plates were set in concrete on the seabed. Four were warmed by 1C, four by 2C and four left at ambient temperature as a control.

At 1C, a species of bryozoan moss (Fenestrulina rugula) became utterly dominant on the four plates. Within two months it reduced the evenness and diversity of the species spread. The researchers also found the marine worm Romanchella perrieri grew an average 70% larger than those under ambient conditions.

At 2C, the results from different plates varied with different growth rates of different species. The researchers speculate that this may be because the higher increase in temperature had a greater shock impact.