(CN) – The world’s oceans have warmed by an average of 1.8 degrees Fahrenheit since preindustrial times, and now researchers say the rising temperatures have had immense impacts on the population sizes of marine species.
In a study released Thursday in the journal Current Biology, researchers report a number of species are fleeing the equator for Earth’s poles.
"The main surprise is how pervasive the effects were," said senior author Martin Genner, an evolutionary ecologist at the University of Bristol. "We found the same trend across all groups of marine life we looked at, from plankton to marine invertebrates, and from fish to seabirds."
Ocean warming causes an array of new issues for marine life, from coral bleaching to loss of breeding grounds to changes in predation habits. The oceans will gradually increase in temperature due to the role they play in regulating Earth’s atmosphere and the effects on it from human activity.
Thursday’s study offers new evidence of the continuing effects of climate change on the oceans’ inhabitants, including the distributions, abundance, and seasonality of marine species. Genner’s team believes, marine species are doing well and thriving on the leading poleward edge of their ranges and doing poorly near the equator.
This trend has been recorded in the past by the U.S. Environmental Protection Agency in species like the American lobster, black sea bass, red hake, and hundreds of others. In a 2016 report, the EPA found that these species had shifted north for cooler waters due to increasing temperatures in their respective environments. In fact, their average center of biomass moved northward by over 109 miles over just 32 years.
In the process of their research, the authors realized they could use existing databases of global species distributions to help prove this hypothesis. Using information gathered by a thorough search of available data in the literature database, the team currently reports on a worldwide analysis of species abundance trends for 304 widely distributed marine species over the last century.
They found just what their hypothesis had predicted: increases in species abundance have been most prominent at the poleward side of species ranges, and abundance decreases have been most prominent at the equatorward side of species ranges.
The results now show that these large-scale changes in the abundance of species is widely evident and well underway. They also suggest the probability that marine species haven’t yet adapted to thrive in warmer ocean conditions. That being said, the researchers suggest that since it is projected that sea temperatures will increase by up to 2.7 degrees Fahrenheit over pre-industrial levels by 2050, there will be a continued push of the latitudinal abundance shifts in marine species, including those of importance for coastal livelihoods.
"This matters because it means that climate change is not only leading to abundance changes, but intrinsically affecting the performance of species locally," Genner says. "We see species such as emperor penguin becoming less abundant as water becomes too warm at their equatorward edge, and we see some fish such as European seabass thriving at their poleward edge where historically they were uncommon."
The study shows climate change has been affecting marine species consistently and considerably. "While some marine life may benefit as the ocean warms, the findings point toward a future in which we will also see continued loss of marine life," Genner said.
The study also included some long-term projected data, which primarily represents the most well-studied regions of the world. The researchers explain that more work is required to understand exactly how climate change has affected marine life in all regions of the world in greater detail.
"We aim to get a better understanding of precisely how marine climate change drives abundance shifts," Genner said. "Is this mainly related to the physiological limits of the species, or instead due to changes in the species with which they interact?"
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