Shell Shocked
Why ocean acidification could mean a literal ‘sea change’ for California mussels
The impact of environmental changes on our world’s oceans is becoming increasingly well documented, with reports of chemical pollution, a trebling of plastic waste and dying coral reefs. With ocean acidification – a shift towards pH-neutral conditions caused by excess CO2 in the atmosphere – mussels look to be the latest to suffer. A team of scientists from the universities of Florida, Glasgow and Chicago analyzed Mytilus californianus to assess the damage – and to discover what it could mean for these mighty mollusks.
The group hit the waters around Tatoosh Island, and compared modern muscle shells with archival records of shells from the 1970s, as well as some dating back 1,000–2,400 years. The team discovered that the calcite crystals within the shells have been uniform in size and structure for thousands of years, but those from the last 15 years show “increased disorder.” Raman spectroscopy also uncovered greater variability in the quantity of calcium carbonate (CaCO3), as well as elevated levels of magnesium – a sign that shell formation has been disrupted.
According to the researchers, this trend in the shell structure corresponds with an increased rate of ocean acidification. Mussels may not find themselves all at sea though, according to lead author of the paper, Sophie McColl: “Variability is the basis of natural selection, and the fact that we now see so much variability in the mussels’ individual shells means there is potential for natural selection to act,” she said in a press release (2). “I have too much confidence in the natural processes of ecology and evolution to think that we’ll have barren oceans.”
- SJ McCoy et al., “A mineralogical record of ocean change: Decadal and centennial patterns in the California mussel”, Glob Change Biol, [Epub ahead of print] (2018).
- Florida State University, “FSU researcher: Ocean acidification means major changes for California mussels”, (2018). Available at: fla.st/2DZbNqb. Accessed March 27, 2018.
A former library manager and storyteller, I have wanted to write for magazines since I was six years old, when I used to make my own out of foolscap paper and sellotape and distribute them to my family. Since getting my MSc in Publishing, I’ve worked as a freelance writer and content creator for both digital and print, writing on subjects such as fashion, food, tourism, photography – and the history of Roman toilets.
