By Summit Voice
FRISCO — The decline and potential collapse of coral reef ecosystems driven by global warming will have impacts to a multitude of other species. Reefs, often described as the nurseries of the sea, are important habitat for many crustaceans, and new research from the University of Florida suggests they will die out along with the corals.
By studying historic fossil records, the research shows a direct link between the health of coral reefs and decapod crustaceans, a group that includes shrimp, crab and lobster.
“We estimate that earth’s decapod crustacean species biodiversity plummeted by more than 50 percent during a sharp decline of reefs nearly 150 million years ago, which was marked by the extinction of 80 percent of crabs,” said Adiël Klompmaker, a postdoctoral researcher at the Florida Museum of Natural History on the UF campus who started the study at Kent State University.
“If reefs continue to decline at the current rate during this century, then a few thousand species of decapods are in real danger. They may adapt to a new environment without reefs, migrate to entirely new environments or, more likely, go extinct,” Klompmaker said.
Although there are signs that a few coral species may be able to adapt to warmer ocean temperatures, coral reef ecosystems overall are in big trouble. According to some projections, up to 20 percent of the world’s reefs may collapse within 40 years, with a much higher percentage affected by the end of the century due to natural and human-influenced changes such as ocean acidification, diseases and coral bleaching.
The study is the first to look at the rise, and subsequent decline, of decapod crustaceans in the fossil record. The scientists built a comprehensive database of fossils from the Mesozoic Era, 252 million to 66 million years ago, from literature records based on museum specimens worldwide.
The data included 110 families, 378 genera and 1,298 species. They examined the patterns of diversity and found an increase in the number of decapod species was influenced by the abundance of reefs, largely due to the role of reefs as a provider of shelter and foraging. Researchers call this period the “Mesozoic decapod revolution” because of the 300-fold increase in species diversity compared with the previous period and the appearance and rapid evolution of crabs.
Compiling information about crustaceans on this scale has historically been a challenge for researchers because most decapods possess a fragile and weakly calcified exoskeleton that does not fossilize well.
“Only a scant fraction of decapod crustaceans is preserved in rocks, so their fossil record is limited,” said study co-author Michal Kowalewski, curator of invertebrate paleontology at the Florida Museum. “But, thanks to efforts of paleontologists many of those rare fossils have been documented all around the world, finally giving us a chance to look at their evolutionary history in a more rigorous, quantitative way.”
“This new work builds a good case for the role of reefs in promoting the evolutionary diversification of crustaceans,” said David Jablonski, a paleontologist in the department of geophysical sciences at the University of Chicago who was not involved in the study. “We have to take their argument for the flipside of that story very seriously. The positive relation between reefs and crustaceans implies that the damage caused to reefs by human activities — from overfishing to ocean acidification — is likely to have cascading consequences for associated groups, including crustaceans.”
Jablonski said the study could serve as an important springboard for future research.
“It would be very interesting to extend this analysis into the Cenozoic Era, the 65 million years leading up to the present day,” Jablonski said. “And it would be valuable to look at the spatial structure of the crustacean diversification, for example how closely their diversification was tied to the extensive reefs in the western Pacific and was damped in the eastern Pacific with their much sparser contingent of reefs.”
Study co-authors include Carrie E. Schweitzer with Kent State University at Stark and Rodney M. Feldmann with Kent State University.