April 2 (UPI) -- Over the last six decades, the makeup of the plankton population found in Britain's coastal and offshore waters has dramatically shifted.
According to a new study, the changes in the abundance and distribution of the microscopic algae and animals that anchor the region's marine food chains serve as evidence of both the growing impacts of climate change and the mounting human pressures on ocean ecosystems.
Because the ocean's plankton population is so important to the many animals higher up the food chain, scientists estimate changes in plankton communities are likely to influence the size and distribution of commercial fish stocks, sea birds and other marine animals. Shifts in regional plankton communities could even alter the ocean's biochemical processes, possibly suppressing oxygen levels.
In reviewing plankton-related survey data over the last 60 years, scientists discovered stark shifts in the number of meroplankton living along the British coastline. Meroplankton are a diverse group of animal plankton that includes lobsters and crabs. Meroplankton only exist as plankton during their infancy and adolescence, eventually growing into large adults that live out their adult lives on the seafloor.
Scientists also measured long term decreases in the abundance of permanent plankton species. Over the last six decades, offshore plankton species have diminished by 75 percent.
"Plankton are the base of the entire marine food web. But our work is showing that climate change has caused plankton around U.K. waters to experience a significant reorganization," study author Abigail McQuatters-Gollop, from the University of Plymouth's Marine Conservation Research Group, said in a news release. "These changes in the plankton suggest alterations to the entire marine ecosystem and have consequences for marine biodiversity, climate change, carbon cycling and food webs including commercial fisheries."
Scientists have long speculated about the impacts of global warming on plankton populations, but the latest research -- published this week in the journal Global Change Biology -- offered concrete evidence of the significant effects of rising ocean temperatures.
"Changes in plankton communities not only affect many levels of marine ecosystems but also the people that depend on them, notably through the effects on commercial fish stocks," said Clare Ostle, researcher with the Marine Biological Association's Continuous Plankton Recorder Survey. "This research is a great example of how different datasets -- including CPR data -- can be brought together to investigate long-term changes in important plankton groups with increasing temperature. These kind of collaborative studies are important for guiding policy and assessments of our changing environment."