The key difference between bioaccumulation and biomagnification is that bioaccumulation refers to the build-up of a toxic chemical in the body of a living organism while biomagnification is the increase of the concentration of a toxic chemical when going along a food chain.
Food chains are important interrelations among the organisms in the ecosystems. It starts with a primary producer, mainly a plant that is photoautotroph. Plants produce food for themselves using sunlight and inorganic carbon sources. Herbivores occupy the second level of a food chain Next levels are commonly occupied by omnivores and carnivores. Food chains nicely explain the dependence of each level for food. Likewise, the food produced at the bottom level is passed to the upper levels. Along with the food, whatever substances in the lower trophic levels can also be passed onto the upper levels along with the nutrients. Bioaccumulation and biomagnification are two phenomena related to the passing of harmful substances along the food chains into the upper levels.
CONTENTS
1. Overview and Key Difference
2. What is Bioaccumulation
3. What is Biomagnification
4. Similarities Between Bioaccumulation and Biomagnification
5. Side by Side Comparison – Bioaccumulation vs Biomagnification in Tabular Form
6. Summary
What is Bioaccumulation?
Bioaccumulation is the accumulation of toxic substances in living organisms. It happens over time. These substances could be heavy metals, pesticides, or organic chemicals. They enter into the living systems via water or food. Bioaccumulation occurs via food chains. The accumulation of toxic substances in the lower trophic levels is less compared to that of higher trophic levels. Usually, a body has mechanisms to remove all the unwanted and toxic products from the body. Hence, bioaccumulation happens when the accumulating rate is much higher than the removal rate. Therefore, if the lifetime of the substance is higher, the impact of it also gets higher.
Figure 01: Bioaccumulation
Usually, kidneys are responsible for removing the majority of unwanted substances from the body. Blood carries them into the kidneys and then the production of urine happens through filtration and selective reabsorption. In order to remove toxins with urine, they should be water soluble. But, bioaccumulative substances are normally fat soluble and braking them down into smaller molecules is not possible. Therefore, they tend to remain in the body.
What is Biomagnification?
Biomagnification is the increase of the concentration of a toxic substance over time when going along a lower level to a higher level in a food chain. The pollutants must be long-lived in order to cause biomagnification. Also, it should be mobile, so that it easily enters into biological systems by means of food or water. If it is not mobile, it may stay inside one organism and will not pass into the next trophic level. Moreover, if they are soluble in fat, they tend to remain in bodies of organisms for a longer period.
Figure 02: Biomagnification
Furthermore, in order for biomagnification to occur, the pollutant must be biologically active. For example, DDT is a chlorinated hydrocarbon which can be biomagnified. It is toxic for insects and has a half-life of 15 years. Heavy metals like mercury, lead, cadmium, zinc are also toxic and can be biomagnified.
What are the Similarities Between Bioaccumulation and Biomagnification?
- Both bioaccumulation and biomagnifications are related to toxic chemicals.
- In both instances, substances are fat soluble.
- Also, these substances are mobile.
- Furthermore, those substances cannot be broken down into smaller molecules.
- In addition, these substances are long-lived.
What is the Difference Between Bioaccumulation and Biomagnification?
Bioaccumulation is the increasing the concentration of a substance in one organism whereas biomagnification is increasing the level as you go up in a food chain. So, this is the key difference between bioaccumulation and biomagnification. Also, a further difference between bioaccumulation and biomagnification is that the bioaccumulation occurs within a tropic level while biomagnification occurs between trophic levels.
Below info-graphic summarizes the difference between bioaccumulation and biomagnification.
Summary – Bioaccumulation vs Biomagnification
Bioactive, fat-soluble, long living toxic substances accumulate when going along the food chain. Moreover, the concentration of a toxic substance increases in organisms. Bioaccumulation and biomagnifications are two processes related to this. Bioaccumulation refers to the increase of the concentration of a toxic substance in an organism while biomagnification refers to the increase of the concentration of a toxic substance when going from a lower level to a higher level in a food chain. Thus, this is a summary of the difference between bioaccumulation and biomagnification.
Reference:
1. “What is Bioaccumulation? – Definition, Causes & Examples.” Study.com, Available here.
2. “Biomagnification.” Wikipedia, Wikimedia Foundation, 16 Feb. 2019, Available here.
Image Courtesy:
1. “MercuryFoodChain-01” By Bretwood Higman, Ground Truth Trekking. – Original text: From www.groundtruthtrekking.org:(CC BY 3.0) via Commons Wikimedia
2. “The build up of toxins in a food chain” By Øystein Paulsen – (CC BY-SA 3.0) via Commons Wikimedia
