November 6, 2012
Aquatic Animals Grow Smaller In The Face Of Global Warming
April Flowers for redOrbit.com - Your Universe Online
A new study reveals that warming temperatures are causing a greater reduction in the adult sizes of aquatic animals than in land-dwelling animals. The findings of this study, published in Proceedings of the National Academy of Sciences (PNAS), are from a collaborative research effort by scientists at Queen Mary, University of London and the University of Liverpool.
Warmer temperatures are disproportionately affecting the body size of marine and freshwater species, which could have implications for aquatic food webs and the production of food by aquaculture.
Using 169 terrestrial, freshwater, and marine species, the team compared the extent to which the adult size of the animals responded to different non-harmful temperatures. This is the largest study of its kind to date.
Dr Andrew Hirst from Queen Mary's School of Biological and Chemical Sciences, in a press release, said, "Aquatic animals shrink 10 times more than land-dwellers in species the size of large insects or small fish. While animals in water decrease in size by 5 percent for every degree Celsius of warming, similarly sized species on land shrink, on average, by just half a percent."
The most likely cause of this difference in size is due to the much lower availability of oxygen in water than in air, according to the research. The need for oxygen is increased in organisms on both land and water during warming periods. Aquatic species have a much harder time meeting this increased demand.
Dr David Atkinson of the University of Liverpool explains, "To satisfy increased demands for oxygen at higher temperatures, aquatic species have fewer options. Reducing the size at which they mature is their way of balancing oxygen supply and demand."
Dr Jack Forster also from Queen Mary's School of Biological and Chemical Sciences adds, "Given that fish and other aquatic organisms provide 3 billion people with at least 15 percent of their animal protein intake, our work highlights the importance of understanding how warming in the future will affect ocean, lake and river dwelling species."