Global Study Highlights True Scale of Ocean Warming

Jenny Griffin

As oceans steadily become warmer, the distribution and breeding times of marine species is changing. This is expected to have significant consequences for the wider marine environment, according to a recent global study.

The study, which was conducted over a three-year period with support from the National Center for Ecological Analysis and Synthesis in California, shows a general and systematic shift in areas such as species distribution and phenology – the timing of natural cycles, such as breeding and migration – on a scale that compares, or even exceeds that observed in land species.

The research report, Global imprint of climate change on marine life, which was published in Nature Climate Change (August 2013), will also be included in the updated Intergovernmental Panel for Climate Change Assessment Report (2014). The international study was undertaken by a team of distinguished scientists from 17 institutions around the world, including the Scottish Association for Marine Science (SAMS), Plymouth University, Aberystwyth University, and the University of Queensland.

According to one of the co-authors of the paper, Professor Camille Parmesan of Plymouth University's Marine Institute, the study offers a "very simple, but important message". 

“This is the first comprehensive documentation of what is happening in our marine systems in relation to climate change,” said Professor Parmesan. “What it reveals is that the changes that are occurring on land are being matched by the oceans. And far from being a buffer and displaying more minor changes, what we're seeing is a far stronger response from the oceans.”

The researchers conducted an extensive literature review of peer-reviewed research papers from around the world, assembling an extensive database of changes recorded in marine life where climate change was considered the driving force. Of the 1,735 changes assessed, approximately 82% were attributed to climate change.

The study reveals that the 'front line' of some ocean species, including phytoplankton, zooplankton and bony fish, is migrating polewards at a speed of 72 kilometers (44,74 miles) per decade, which is much faster than the average speed of 6 kilometers (3,73 miles) per decade witnessed for terrestrial species, even though land temperatures are warming three times faster than sea surface temperatures.

The team also found that springtime phenology in the oceans occurred more than four days earlier, compared to a two day phenological advancement seen in terrestrial ecosystems. While response times varied between species, invertebrate zooplankton species and the larvae of bony fish exhibited the greatest response, showing a phenological advancement of up to eleven days.

“Most of the effects we saw were as expected from changes in climate. So, most shifts in the distributions of, say, fishes and corals, were towards the poles, and most events in springtime, like spawning, were earlier,” said Professor Mike Burrows from SAMS. “Some of the most convincing evidence that climate change is the primary driver behind the observed changes could be found in footprints that showed, for example, opposing responses in warm-water and cold-water species within a community; and similar responses from discrete populations at the same range edge.”

“Our research has shown that a wide range of marine organisms, which inhabit the intertidal to the deep-sea, and are found from the poles to the tropics, have responded to recent climate change by changing their distribution, phenology or demography,” said Dr Pippa Moore, from Aberystwyth University. “These results highlight the urgent need for governments around the globe to develop adaptive management plans to ensure the continued sustainability of the world's oceans and the goods and services they provide to human society.”

Journal Reference

Elvira S. Poloczanska, Christopher J. Brown, William J. Sydeman, Wolfgang Kiessling, David S. Schoeman, Pippa J. Moore, Keith Brander, John F. Bruno, Lauren B. Buckley, Michael T. Burrows, Carlos M. Duarte, Benjamin S. Halpern, Johnna Holding, Carrie V. Kappel, Mary I. O’Connor, John M. Pandolfi, Camille Parmesan, Franklin Schwing, Sarah Ann Thompson, Anthony J. Richardson. Global imprint of climate change on marine life. Nature Climate Change, 2013; DOI: 10.1038/nclimate1958

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