Figure 1: Fish in Contaminated Water https://stock.adobe.com/search?k=dead+fish+water&asset_id=431095511
Human activities contribute to various forms of pollution that may directly or indirectly travel into water bodies and contaminate aquatic ecosystems. Common aquatic pollutants include hydrocarbons, polychlorinated biphenyls, plastics, heavy metals such as mercury, lead, and chromium, and various forms of pesticides. Continued exposure to these pollutants, especially at high levels, may cause extensive oxidative stress to fish, which can be defined as an imbalance of antioxidant systems (Padmini, 2010).
Continued environmental stress caused by pollution triggers cellular Mitochondria to produce reactive oxygen species (ROS). These ROS are free radicals that can cause permanent damage to proteins. Fish have been found to respond physiologically to protein damage caused by ROS with “cytoprotective” heat shock proteins (HSP), also known as stress proteins. These heat shock proteins function to mend the proteins damaged by ROS by facilitating appropriate protein folding and conformations. Heat shock proteins are generated in high volumes upon the stimulus of oxidative stress caused by pollution within the aquatic environment (Padmini, 2010).
Figure 2: Heat Shock Protein Stimulus in Fish (Mohanty, 2018)
Without the response of heat shock proteins, fish may continually accumulate damaged macromolecules. This accumulation can then hinder reproduction or cause infection or death. Therefore, heat shock proteins allow fish to combat (to a degree) the environmental stress they may be subject to. Researchers track levels of these cellular components to measure aquatic contamination and disturbance. With this, heat shock proteins can be used as a method to assess environmental quality overall (Padmini, 2010).
References
Mohanty BP, Mahanty A, Mitra T, Parija SC, Mohanty S (2018) Heat shock proteins in teleosts. Regulation of Heat Shock Protein Responses 13:71-94. doi:10.1007/978-3-319-74715-6_4.
Nattawit. (n.d.). Dead fish floating on water surface, Ecosystem and environmental problem from contaminated water. Adobe Stock. Retrieved from https://stock.adobe.com/search?k=dead+fish+water&asset_id=431095511.
Padmini E (2010) Physiological adaptations of stressed fish to polluted environments: role of heat shock proteins. Reviews of Environmental Contamination and Toxicology 206:1-27.doi:10.1007/978-1-4419-6260-7_1.