Other than causing pollution, the aquaculture industry is also susceptible to pollution. Pollutants from agriculture and industries can result in air and water pollution. Water pollution often originates from the over-application of fertilisers and waste materials from farms, which can result in Eutrophication. Pollutants from industrial emissions and waste products of farms can result in “acid” rain, which is also deposited in water bodies. “Runoff and direct deposition can lead to water acidic enough to harm or kill fish and other aquatic organisms” (Hill, 2010).
Firstly, the over-application of fertilisers from agriculture and animal farms can result in Eutrophication. Fertilisers may be washed off into water bodies, leading to algal bloom. Fish and other aquatic species suffocate when their habitat doesn’t have enough dissolved oxygen in surface water. Also, dead species can make water quality poor and produce unpleasant odours (Kremser and Schnug, 2002).
Ocean Acidification refers to the lowering of the pH of water bodies, resulting in more acidic living environments for marine creatures. From Hill (2010), Ocean Acidification has negative impacts on aquatic life (p.158) (Figure 1).
Some organisms that are severely affected by ocean acidification are corals and shellfish. “Increasing atmospheric carbon dioxide concentrations are reducing ocean pH and carbonate ion concentrations, and thus the level of calcium carbonate saturation. Experimental evidence suggests that if these trends continue, key marine organisms—such as corals and some plankton—will have difficulty maintaining their external calcium carbonate skeletons” (Orr et al., 2005). This may threaten oyster production in many parts of the world such as Australia, the United States and Scotland (Fitzer, 2019).
With the decline in corals, many aquatic creatures lose their habitats too. Next, the abilities of some fishes may be hindered. For example, the ability of clownfish to detect predators is decreased in more acidic waters. When these organisms are at risk, the entire food web may also be at risk (NOAA, 2020). Also, with the increased acidity, it can increase the bioavailability of heavy metals, which may be ingested by marine creatures, bioaccumulate and enter our food chain (Zeng et al., 2014).
In summary, the effects of pollution do not just end at the source, but rather it can be transported, transformed and even remobilised. The aquaculture industry is not so simple after all as it can be affected by a multitude of factors. In becoming more aware of this industry, perhaps we can become more conscious consumers and also urge farmers to engage in more sustainable practices for better quality food.
Trailing off,
Jade and Ridzuan
References
Fitzer, S. (2019). The world’s shellfish are under threat as our oceans become more acidic. [online] Phys.org. Available at: https://phys.org/news/2019-01-world-shellfish-threat-oceans-acidic.html#:~:text=Shellfish%20are%20creatures%20which%20produce,and%20carbonate%20from%20the%20water [Accessed 7 Sep. 2020].
Hill, M.K. (2010) Understanding Environmental Pollution (3rd ed). Cambridge: Cambridge University Press. https://doi.org/10.1017/CBO9780511840654
Kremser, U. and Schnug, E. (2002). Impact of fertilizers on aquatic ecosystems and protection of water bodies from mineral nutrients. ResearchGate. Available at: https://www.researchgate.net/publication/240641590_Impact_of_fertilizers_on_aquatic_ecosystems_and_protection_of_water_bodies_from_mineral_nutrients
National Oceanic and Atmospheric Administration. (2020). Ocean acidification. Available at: https://www.noaa.gov/education/resource-collections/ocean-coasts/ocean-acidification [Accessed 7 Sep. 2020].
Orr, J.C., Fabry, V.J., Aumont, O., Bopp, L., Doney, S.C., Feely, R.A., Gnanadesikan, A., Gruber, N., Ishida, A., Joos, F., Key, R.M., Lindsay, K., Maier-Reimer, E., Matear, R., Monfray, P., Mouchet, A., Najjar, R.G., Plattner, G.-K., Rodgers, K.B., Sabine, C.L., Sarmiento, J.L., Schlitzer, R., Slater, R.D., Totterdell, I.J., Weirig, M.-F., Yamanaka, Y. and Yool, A. (2005). Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature, 437(7059), pp.681–686. https://doi.org/10.1038/nature04095
Zeng, X., Chen, X., Zhuang, J. (2014). The positive relationship between ocean acidification and pollution. Marine Pollution Bulletin. http://dx.doi.org/10.1016/j.marpolbul.2014.12.001
