Scientists know that Co2 emissions are not always good. In the marine department, the common thought was that the creatures hit hardest by CO2 emissions were plankton, coral, and other shell fish that are composed as CaCO3. Now a new scientific experiment posted in Nature Climate Change has shown that fish also face severe negative side effects of CO2 emissions.
Fish experienced birth defects, a high death rate, and freakish behavioral changes – actual affects on the brain, when exposed to high levels of CO2. The study consisted of several experiments. In the first experiment clown fish larva, (like Nemo) were raised in two tanks. One tank had an atmospheric CO2 concentration of 450 parts per million (ppm). The second tank had an atmospheric CO2 concentration of 900 ppm. To put things into perspective the current atmospheric CO2 concentration is about 390 ppm, however that figure in the world’s oceans varies from region to region.
The clownfish from the two tanks were then tested to see how they responded to the odor of a predator. The clownfish were given the option of swimming down two paths, one path that contained the scent of the predator and the other that did not.
The clownfish brought up in the low CO2 environment, 450 ppm, avoided the path with the predator odor and chose the “safe route”. The clownfish brought up in the high CO2 environment, 900 ppm, often did not avoid the “non safe route” and swam down the path with the predator odor.
The scientist went even further with the clownfish on the suspicion that the CO2 interfered with neurotransmitter receptors in the fish’s brain. By introducing a compound that blocked the negative effects caused by the CO2 scientists found that the interferences had no effect with the fish raised in the low CO2 environment and actually fixed the negative effects of the clown fish raised in the high CO2 environment.
In the second experiment wild damsel fish (little blue fish sort of like Dory) were captured and placed in two separate tanks. One tank had the low CO2 environment, 450 ppm, and the other a high CO2 environment, 900 ppm. The wild damsel fish live in the tanks for several days and then were subjected to a test.
In this test, the scientists placed the wild fish in a T shaped maze fish tank and recorded each fish’s preference for right or left turns. A significant number of the wild damsel fish from the low CO2 showed a fondness for either right or left turns, while the wild damsel fish from the high CO2 tank turned at random.
What this showed the scientists was that the high CO2 negatively impacted the fish’s ability to take part in survival behavior like schooling or escaping from a predator by turning away from danger – behavior these wild fish had before the capture and experiment. Once again the scientists introduced the same compound to block the negative effects of the CO2 and the fish from the high CO2 tank regained their proper survival skills.
The study shows scientists thatCO2 impacts not just the creatures on the bottom of the ocean, but a much broader spectrum of marine fish. These fish cannot acclimate successfully to a high CO2 environment, making them more susceptible to predators. Just another way increased carbon emissions could mess with our precarious food chain.
Andrew Meggison was born in the state of Maine and educated in Massachusetts. Andrew earned a Bachelor’s Degree in Government and International Relations from Clark University and a Master’s Degree in Political Science from Northeastern University. Being an Eagle Scout, Andrew has a passion for all things environmental. In his free time Andrew enjoys writing, exploring the great outdoors, a good film, and a creative cocktail. You can follow Andrew on Twitter @AndrewMeggison