Scientists from the University of Washington have found that global warming is destroying many marine parasites. The study, which has become the largest and most detailed report on the abundance of marine parasites, Proceedings of the National Academy of Sciences.
The researchers examined 699 canned specimens of eight fish species stored in the museum, which they returned to after the study. The fish has lived in the Puget Sound bay system all its life. The scientists carefully cut open the preserved specimens and then identified and counted their internal parasites. In total, they found 17,259 parasites from 85 species. There were even crustaceans among them, but tapeworms turned out to be the most numerous group.
It turned out that from 1880 to 2019, the number of parasites with three or more hosts decreased by 11%. 10 parasites disappeared completely, and 9 of these had three or more hosts.
The authors evaluated three possible causes of such changes: reduced parasite hosts, water pollution, and ocean surface temperature changes. It was the temperature increased by 1 degree Celsius that was more strongly associated with the disappearance of the parasites than any other parameter.
The results show that parasites with one or two host species are highly resistant to temperature change, but parasites with three or more hosts are at risk. While their extinction may seem like good news, it can damage ecosystems. Scientists believe parasites with complex life cycles likely play an important role in moving energy through food webs and supporting top predators.