Marine animals that live in warm as well as acidic oceans are dissolving quickly under conditions at the Northern California coast, says a study from the University of California, Davis. This applies especially to the bryozoans.
Scientists published their study in the journal Proceedings of the Royal Society B: Biological Sciences. Researchers from the UC Davis Bodega Marine Laboratory raised bryozoans, more commonly called "moss animals" in seawater tanks. They exposed them to different levels of water temperature, food, and acidity.
Growing them in warm waters and then exposing them to acidity dissolved the bryozoans quickly. Large parts of their skeletons got dissolved in just two to three months, according to Science Daily. Even though they expected some thinning or reduced mass, lead author Dan Swezey, a recent Ph.D. graduate in professor Eric Sanford's lab at the UC Davis Bodega Marine Laboratory said that they witnessed entire features just dissolving in front of their eyes!
Bryozoans are colonial animals, which look like corals but are not related to them. They are present more in California kelp forests. Their honeycomb-shaped skeletons are built from calcium carbonate. In warm conditions, bryozoans changed their chemical composition as they built up higher levels of magnesium into their skeletons, especially when they consumed less food. Due to acidic conditions in coastal California, the animals dissolved to changes in the environment.
While it is not known why bryozoans tend to take on more magnesium to their skeletons under higher temperatures, they do seem to be more vulnerable to ocean acidification. Bryozoans also grow in "connected colonies." Experiments showed that the animals closed off some parts of their bodies even as they underwent ocean acidification. Their energy was channelized into new growth.
Hence, calcified animals are vulnerable to ocean acidification even as the ocean absorbs a lot of atmospheric carbon that is released through the burning of fossil fuels. Worryingly, the oceans have been found to absorb 25 to 30 percent of carbon dioxide emissions and almost 85 percent of the gas in the long run, according to Scientific American.
"Marine life is increasingly faced with many changes at once," said co-author Sanford, a professor in the UC Davis Department of Evolution and Ecology. "For bryozoans, their response to warmer temperature makes them unexpectedly vulnerable to ocean acidification. The question now is whether other marine species might respond in a similar way."
YouTube/American Museum of Natural History
