While global climate change is still widely disputed, indications of warming oceans are evident as major shifts in marine life are being reported off the coasts of Australia. In turn, major ecosystems, including cold-water marine habitats, as well as human recreational and commercial activities are at risk.
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According to a three-year international study led by CSIRO’s Climate Adaptation Flagship and University of Queensland ecologists Elvira Poloczanska and Anthony Richardson, warming oceans that are resulting from increasing air temperatures, are causing a noticeable impact on the breeding patterns and habitat of marine life. Researchers expected marine organisms to respond to climate change at the same rate as terrestrial species. However, “despite sea surface temperatures warming three times slower than land temperatures,” according to Dr. Poloczanska, marine species are relocating towards cooler regions “at the average rate of 72 kilometers per decade, which is considerably faster than terrestrial species moving poleward at an average of six kilometers per decade.”
Further evidence indicates that breeding and migration periods for marine life are occurring much earlier than those of land species, advancing by 4.4 days each decade. It is thought that the rapidly warming temperatures over both land and ocean might be the cause for early growing seasons and the time of reproduction. Additionally, Dr. Poloczanska states “anthropogenic carbon dioxide uptake by the oceans is altering seawater carbonate chemistry, which can impact some marine organisms.”
These changes, while seen globally, are strongly evident in Australia’s marine environment. Australia’s south-east tropical and subtropical species of fish, mollusks and plankton are shifting further south through the Tasman Sea. The distribution of sea birds in the Indian Ocean is also shifting south. There is also a noticeable loss of cool-water seaweeds from regions north of Perth. “Essentially, these findings indicate that changes in life events and distribution of species indicates we are seeing a widespread reorganization of marine ecosystems…” said Dr. Poloczanska.
The results from marine habitat and breeding changes are likely to have severe repercussions on human industries. There is potential for decline in specific species normally found in recreational and commercial fishing activities. However, according to Dr. Poloczanska, it is also possible that the warming seas could provide breeding grounds for new species, resulting in new fishing opportunities.
This study has been published in Nature Climate Change, and is based on a review of peer-reviewed literature from around the world.
Read more at CSIRO.
Australian coast image via Shutterstock