Life Changes As Sea Warms

As the advance of global warming becomes more certain, accurate predictions about its impacts are still largely guesswork. How can we know what long-term warming will do to complex ecosystems? One way is to do a large experiment and see what happens. A new study published in the journal Ecology shows that artificially warming the seawater by 3.5oC in a California bay had dramatic effects on 150 species of seaweeds and animals.

David Schiel (University of Canterbury in Christchurch, New Zealand), John Steinbeck (Tenera Environmental, California , USA) and Michael Foster (Moss Landing Marine Labs, California, USA) compiled a 20-year study of coastal sea life along 2 kilometers of a bay affected by hot water from the cooling system of a power generating plant. Many kelp and other large seaweeds virtually disappeared from the bay, grazing snails and sea urchins increased, abalone died and habitats changed throughout the bay.

The study showed that one of the main predictions about the effects of seawater warming on ocean life was wrong: there was no replacement of cold-water species by warm-water species. Instead, a few abundant, widely distributed species were directly affected by the increased temperatures and triggered complex responses throughout the coastal marine communities. “Our study clearly shows that changes in marine systems due to warming are unlikely to be simple. Whether we come up with better ways to predict changes remains to be seen,” said Professor Schiel.

Complete article: http://www.esajournals.org/esaonline/?request=get-archive&issn=0012-9658&volume=085

Ecology, published by the Ecological Society of America; Volume 85, Issue 7; pages 1833-1839; published July 2004.

Contact Information:

New Zealand:
David Schiel, Canterbury University, Christ church
Ph: 643 364 2031
Email: david.schiel@canterbury.ac.nz

USA:
Michael Foster, Moss Landing Marine Labs, Moss Landing, California
Ph: 831 771 4435
Email: foster@mlml.calstate.edu