Climate change can affect the smell of the sea
3 April 2022
While this is beneficial in reducing climate change, it has significant implications for ocean ecology. The extra CO2 that civilization has poured into the atmosphere has raised ocean acidity by 43 percent over the previous two centuries. By 2100, the ocean is expected to be 2.5 times more acidic than currently.
The researchers initially looked at Dicentrarchus, a juvenile European sea bass, in ocean water with typical carbonic acid levels. Next, the fish was studied in water that simulated the acid levels projected by the end of the century. The behavioral differences were startling. The fish were less likely to swim and more likely to “freeze” for five seconds or more, indicating fear. Most crucially, they had to come quite close to something to smell it—not the ideal move if the source of the fragrance is a potential threat
Effects on sea life smell
“In seawater acidified with CO2 levels expected for the end of the century, the sense of smell of sea bass was impaired by up to half.” According to the study’s primary author Cosima Porteous, a fish physiologist at the University of Exeter in the United Kingdom, “their capacity to identify and respond to some scents associated with food and frightening situations was more significantly influenced than for other odors.” “We believe this is due to acidified water altering how odorant molecules link to olfactory receptors in the fish’s nose, limiting their ability to discriminate crucial cues.”
- Many animals have genetic resources, such as the ability to create extra sensory receptors, to help them cope with change or stress. The researchers hoped to check if the fish had a toolbox of genes that could assist them in overcoming their loss of smell, but they didn’t find anything like that.
- “One method to smell anything better is to have more receptors recognizing these smells,” Porteous tells Marlene Cimon’s at Popular Science. “This increases the possibility that particular smell will be noticed, and hence increases the expression of these receptors.” “Another option is for them to develop a slightly different receptor that functions better at lower ph.
- The acid-washed fish produced fewer smell receptors, making detecting odors even more challenging.
- Acidification is likely to affect more than simply sea bass. According to Porteous, the findings should apply to practically all fish species, including cod, salmon, haddock, other economically important species, and marine invertebrates such as lobster.
- The scientists will compare the acid levels in today’s ocean to those in pre-industrial eras in the next phase to see if fish are already having problems with their sniffers. As with a slew of other global issues, the solution to the problem is to confront carbon emissions head-on, whether we can smell them or not.