According to the Environmental Protection Agency of the United States , bioaccumulation occurs at the base of a food web, usually within primary producers like phytoplankton. The absorbed toxins build up in their tissues at a rate faster than they can be metabolised. What causes biomagnification? Even though biomagnification is a natural phenomenon, the condition is exacerbated by rapid anthropological activities like agriculture, mining and industrial activities.
Organic contaminants. Chemicals present in manures, beauty products, and cleaning products such as soap, can escape into the food chain and have an adverse impact on the health of humans and wildlife. Eutrophication is a phenomenon when an organism that thrives in these conditions experiences exponential growth and suddenly has an overwhelming population.
This can then lead to the disruption of its ecosystem, due to extreme competition for the available resources. Agriculture and industrial activities. Industries and agriculture release toxic substances that are absorbed by the soil, lakes, oceans and rivers. Synthetic man-made chemicals called Persistent Organic Pollutants , or POPs, are of primary concern when looking at bioaccumulation and biomagnification. These chemicals do not easily break down in the environment and can build up in the fatty tissues of living organisms.
Although the production of these chemicals was banned during the s and s, they can still be found in the oceans as well as the tissues of many marine animals because of their ability to 1.
Bioaccumulation occurs at the base of a food web, usually within primary producers like phytoplankton. These microscopic photosynthetic organisms absorb POPs directly from the seawater and accumulate them in their bodies over time.
The toxins build up in their tissues because they are absorbed from the water at a rate faster than they can be metabolized. Biomagnification occurs when slightly larger organisms called zooplankton feed upon the contaminated phytoplankton and in turn absorb POPs into their own tissues at a higher concentration.
The more contaminated phytoplankton a zooplankton eats, the more pollutants it will have in its body. In other words, the POPs can be passed from producer to consumer to consumer, to consumer, and so on… Biomagnification can continue all the way up the food web or chain. Climate Feedback. Ocean Acidification. Rising Sea Level. Mackay and a. Zooplankton refers to small marine animals that float in the seas. They consume the phytoplankton and thus take in the toxin.
Over time, the toxin concentration increases up to two parts per billion which represents about a ten-fold increase over the previous concentration. Whenever the small fish feed on the zooplanktons, they consequently take up the toxins which get absorbed in their fatty tissues. As a result, accumulation occurs and the concentrations build up to about 20 parts per billion which is another ten-fold increase.
Again, when the large fish graze on the smaller fish for food, they consume the toxins that accumulate in their fatty tissues. The concentrations become higher up to ranges of 80 to parts per billion. This is about four to five fold increase in the toxic levels. The organisms at the top of the food chain including the marine mammals such as dolphin, sea birds, and humans gradually build up the toxins in their tissues such as their liver when they consume the large fish.
The levels of concentrations here increase to the highest ranges of 10, to 15, parts per billion. Sonia Madaan is a writer and founding editor of the science education blog EarthEclipse. She loves writing on topics related to space, environment, chemistry, biology, geology and geography. When she is not writing, she loves watching sci-fi movies on Netflix.
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