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Cambridge University Science Magazine
A first-time global analysis looking into the way ocean habitats respond to projected effects of climate change finds that marine food chains are likely to collapse as a result of changing water conditions. The study, performed by marine ecologists from the University of Adelaide, Australia, compiled data from 632 published experiments to tease out broad changes expected to occur in oceanic ecosystems across the globe in response to predicted trends of rising CO2 emissions and the anticipated planet-wide effects they will exert.

Increased atmospheric temperatures and CO2 levels would cause the oceans to become warmer and more acidic. The analysis of the scientists shows that this in turn would have negative effects on the number and diversity of fish species directly as well as indirectly, since species that form habitats for fish to live in, corals for example, would not fare well in these altered conditions. Most species are predicted to only have very limited capacity to adjust to a rise in temperature and acidity. Moreover, the scientist point out other research which concludes that species that take a long time to reach sexual maturity and that have few offspring, such as marine mammals, would not be able to adapt quickly enough to drastic changes in their environment.

The core prediction of the analysis is that a decrease in number and diversity of key species in the food chains of most habitats would eventually lead to these food chains breaking down. Since fish is an important source of animal protein for many people and the fishing industry a key area of employment especially in developing countries, the consequences of marine food chain collapse for the human population would be dire indeed.

DOI: 10.1073/pnas.1510856112

Written by Janina Ander.