BiomagnificationBiomagnification

BiologyBiology

When we try to pick out anything When we try to pick out anything by itself, we find it hitched to by itself, we find it hitched to everything else in the universe. everything else in the universe. John Muir John Muir

BiomagnificationBiomagnification

Definition:Definition:BiomagnificationBiomagnification, , also known also known

as as bioamplificationbioamplification, or , or biological magnificationbiological magnification is is the the increase in concentration of a increase in concentration of a substance, substance, such as the pesticide such as the pesticide DDTDDT, that occurs in a food chain, that occurs in a food chain

Biomagnification Through the Biomagnification Through the Food ChainFood Chain

Energy Available to Consumers at Energy Available to Consumers at Next Trophic LevelNext Trophic Level

Energy Lost by Respiration

Energy Lost by Death and Decay

Energy Lost by Excretion

Energy Lost by Egestion of

Feces

Energy Ingested

Food Chain ExampleFood Chain Example

Let’s look at our food chain to see how Let’s look at our food chain to see how biomagnification works:biomagnification works:

Food ChainFood Chain

Let’s say, for example, that Let’s say, for example, that each piece of each piece of plant material has one microscopic drop of plant material has one microscopic drop of methyl mercury. methyl mercury.

Food ChainFood Chain

One insect eats 25 pieces of plant One insect eats 25 pieces of plant material, that would mean that each insect material, that would mean that each insect would have _______ microscopic drops of would have _______ microscopic drops of methyl mercury in its body. methyl mercury in its body.

Food ChainFood Chain

If one small fish needs 10 insects to If one small fish needs 10 insects to live, then one fish would have _____ live, then one fish would have _____ microscopic drops of methyl microscopic drops of methyl mercury. mercury.

Food ChainFood Chain

One big fish eats 5 small fish to live. So, One big fish eats 5 small fish to live. So, one big fish would collect a total of _____ one big fish would collect a total of _____ microscopic drops of methyl mercury in its microscopic drops of methyl mercury in its body. body.

Food ChainFood Chain

What about you and me? Lets say we eat What about you and me? Lets say we eat 1 big fish a day for 3 days. We would 1 big fish a day for 3 days. We would collect total of ______ drops of methyl collect total of ______ drops of methyl mercury in our body over the 3 days. This mercury in our body over the 3 days. This is how biomagnification works!is how biomagnification works!

Food ChainFood Chain

Now let’s say that methyl mercury makes Now let’s say that methyl mercury makes living things sick. The more methyl living things sick. The more methyl mercury in the living organism, the more mercury in the living organism, the more sick it would get. From our example sick it would get. From our example above, which organism will be most above, which organism will be most affected by the toxin methyl mercury?affected by the toxin methyl mercury?

Other Organisms Affected by Other Organisms Affected by BiomagnificationBiomagnification

Peregrine FalconPeregrine Falcon The Peregrine Falcon became an The Peregrine Falcon became an

endangered species because of the endangered species because of the overuse of pesticides such as DDT during overuse of pesticides such as DDT during the 1950s, 60s, and 70s. Pesticide the 1950s, 60s, and 70s. Pesticide biomagnification interfered with biomagnification interfered with reproduction, thinning eggshells and reproduction, thinning eggshells and reducing the number of eggs that survived reducing the number of eggs that survived to hatching. The organochlorine build-up in to hatching. The organochlorine build-up in the falcon's fat tissues resulted in less the falcon's fat tissues resulted in less calcium in the eggshells, leading to more calcium in the eggshells, leading to more fragile eggs. In several parts of the world, fragile eggs. In several parts of the world, such as the eastern USA and Belgium, this such as the eastern USA and Belgium, this species became extinct as a result. species became extinct as a result.

Bald EagleBald Eagle

Bald EagleBald Eagle

Once a common sight in much of the Once a common sight in much of the continent, the Bald Eagle was severely continent, the Bald Eagle was severely affected in the mid-20th century by a variety affected in the mid-20th century by a variety of factors, among them thinning of egg shells, of factors, among them thinning of egg shells, attributed to the use of the pesticide DDT. attributed to the use of the pesticide DDT. DDT itself was not lethal to the adult bird, but DDT itself was not lethal to the adult bird, but it interfered with the bird's calcium it interfered with the bird's calcium metabolism, making the bird either sterile or metabolism, making the bird either sterile or unable to lay healthy eggs. Female eagles unable to lay healthy eggs. Female eagles laid eggs that were too brittle to withstand the laid eggs that were too brittle to withstand the weight of a adult.weight of a adult.

Pesticide ResistancePesticide ResistanceIn the beginning, In the beginning, most pests were most pests were sensitive to DDT but sensitive to DDT but a few were resistanta few were resistant

The resistant forms The resistant forms survived and survived and reproducedreproduced

In the end, most In the end, most pests were resistant pests were resistant to DDTto DDT

Horton, in Dr. Seuss’sHorton, in Dr. Seuss’s Horton Horton Hears a WhoHears a Who

““We’ve GOT to We’ve GOT to make noise in make noise in greater greater amounts! So, amounts! So, open your open your mouth, lad! For mouth, lad! For every voice every voice counts!”counts!”