CoECRS Science Alert 5 Aug 13;
Profound changes are taking place in marine life around the planet in response to global warming, an international team of scientists has found.
Marine species – including fish, shellfish, crustaceans, plankton, mangroves and seagrasses – are now shifting the areas they inhabit at an average rate of 72 kilometres per decade as a result of one degree of planetary warming.
Some species have moved up to 470 kms in a decade , says a report in the journal Nature Climate Change by scientists from Australia, Germany, South Africa, the UK, the US, Denmark, Spain and Canada. This contrasts with an average 6 km movement by life on land. Most of the movement is towards the poles as sea life searches for cooler waters.
Sea creatures are now going into their seasonal breeding cycles an average of 4.4 days earlier - almost twice as early as land animals – in response to warmer waters, they found.
The team analysed 208 reports on marine life and fisheries, covering 857 different marine species or groups from around the world for changes in their normal distribution, abundance, breeding cycles, community composition, shell formation and age structure. It is the biggest marine study of its kind so far and fills an important blank in understanding of global change.
“The results were quite a shock,” says co-author Professor John Pandolfi of the ARC Centre of Excellence for Coral Reef Studies and University of Queensland. “We found that changes in sea life attributable to a one degree increase in the Earth’s overall temperature appear much greater than those seen in life on land so far.”
The oceans are estimated to have absorbed 80 per cent of the extra heat put into the Earth system by human use of fossil fuels, but have nevertheless warmed more slowly than the land owing to their huge mass, he says.
“This makes the very large changes in the behaviour of sea life all the more surprising. We put it down mainly to the fact that marine organisms often produce substantial numbers of floating larvae that are easily dispersed by ocean currents.”
The study took in research from all the world’s oceans, with a particular focus on what is happening on the east and south coasts of Australia, both US coastlines, the European Atlantic and Mediterranean.
It included marine mammals, fish, seabirds, turtles, squid, plankton, molluscs, deep sea invertebrates and crustaceans, mangroves, seagrasses and deepwater algae and covered the polar, temperate, subtropical and tropical oceans.
It found phytoplankton – which provide the basic food for all life in the seas – are now blooming an average of six days earlier in the season, compared with land plants. Baby fish appear to be hatching around 11 days earlier in the season.
The researchers caution that these big shifts in the timing of major events could produce disruption to ocean food webs. This has implications for all sea life, as well as for humans who depend on the sea for food, says Prof. Pandolfi.
“When you see changes as large as these, life generally has three options – migration, adaptation or extinction. In the case of migration and extinction, these can directly affect industries like fishing and tourism which depend on local sea life.
“On the other hand, as sea life moves around the planet and adapts to the changes, new opportunities may also open up – so it isn’t all bad news,” he says. “Your favourite fishing spot might not be there any more – but another may appear somewhere else.
“The study tells us that the situation with life in the oceans is now very dynamic and fast-changing, and marine managers, fishers and others who depend on the seas for a living need to take account of that.
“For example, we need to minimise the sorts of stresses we put on sea life to give it the best chance of re-establishing in new places and environments.”
As the first worldwide investigation of the impacts of climate change on life in the oceans, the study complements 28,586 similar observations carried out on land and will be an important input to the Intergovernmental Panel on Climate Change (IPCC) as it prepares its next report on global warming.
“The results of this work are so clear-cut that it is no longer tenable to suggest that global warming isn’t happening, or that we humans don’t have a hand in it,” Prof, Pandolfi adds. “The changes are on a par with those we see in the fossil record when the Earth previously underwent large episodes of warming.”
Their paper “Global imprint of climate change on marine life” by 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 and Anthony J. Richardson appears today in the journal Nature Climate Change.
Global Investigation Reveals True Scale of Ocean Warming
Science Daily 4 Aug 13;
Warming oceans are causing marine species to change breeding times and shift homes with expected substantial consequences for the broader marine landscape, according to a new global study.
The three-year research project, funded by the National Centre for Ecological Analysis and Synthesis in California, has shown widespread systemic shifts in measures such as distribution of species and phenology -- the timing of nature's calendar -- on a scale comparable to or greater than those observed on land.
The report, Global imprint of climate change on marine life, will form part of the Intergovernmental Panel for Climate Change Assessment Report due for publication in 2014, and is published in this month's Nature Climate Change. It was undertaken by eminent scientists at 17 institutions across the world, including the University of Queensland, Plymouth University, Aberystwyth University, and the Scottish Association for Marine Science (SAMS).
One of the lead authors of the report, Professor Camille Parmesan, National Marine Aquarium Chair in Public Understanding of Oceans and Human Health within Plymouth University's Marine Institute, said the study offered a "very simple, but important message."
Professor Parmesan said: "This is the first comprehensive documentation of what is happening in our marine systems in relation to climate change. 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 research team assembled a large database of 1,735 changes in marine life from the global peer-reviewed literature which helped them investigate impacts of climate change. The team found that 81% of changes were in a direction consistent with climate change.
The evidence showed that the leading edge or 'front line' of some marine species, such as phytoplankton, zooplankton and bony fish, is moving towards the poles at the average rate of 72km per decade, which is considerably faster than the terrestrial average of 6km per decade -- and this despite the fact that sea surface temperatures are warming three times slower than land temperatures.
They also found that spring phenology in the oceans had advanced by more than four days, nearly twice the figure for phenological advancement on land. The strength of response varied among species, but again, the research showed the greatest response in invertebrate zooplankton and larval bony fish, up to 11 days in advancement.
Professor Mike Burrows at SAMS said: "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."
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.
Dr Pippa Moore, Lecturer in Aquatic Biology from Aberystwyth University, said: "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.
"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
