Bioaccumulation

Bioaccumulation and Biomagnification

How Toxins Move through a Food Web

Multiple Choice

_____________ is the increase in concentration of a pollutant in a food chain

• Bioaccumulation

• Biomagnification

Multiple Choice

___________ is the increase in concentration of a pollutant in an organism

• Bioaccumulation

• Biomagnification

BPA = bisphenol A

Multiple Choice

Regents Check

Which environmental change would cause the

greatest reduction in the biodiversity of a large

ecosystem?

• building a new home

• building a new store in a shopping mall

• widespread use of pesticides

• widespread recycling programs

Multiple Choice

Regents Check

The bottom of Onondaga Lake in upstate New

York contains large amounts of pollutants. One

proposal to clean the lake bottom requires that

the pollutants be removed and stored nearby.

People who live near the proposed storage sites

are opposed to this plan. The officials who must

decide on the proposal will examine both the

benefits and risks of the plan. The decision made

by the officials will most likely involve

• increased industrialization

• direct harvesting

• an increase in finite resources

• consideration of trade-offs

Open Ended

Regents Check

There has been an increase in the number of dead birds found on the beaches of the Great Lakes. These birds were poisoned by a bacterial toxin in the lake water. The birds do not ingest enough water to become sick directly from the toxin found in the lake water. Scientists think that the cause of the increasing bird deaths lies with an invasive species— the zebra mussel. This freshwater organism was introduced into the Great Lakes accidentally by humans, and has become well established in the Great Lakes. Zebra mussels filter out microscopic organisms, as well as the toxins found in the lake water. The toxins

become concentrated in the zebra mussels, which are eaten by small fish called gobies, and the gobies are eaten by the birds. The concentration increases in each level of the food chain. It appears that the introduction of the zebra muscles into the Great Lakes has resulted in a new food chain that increases the concentration of the naturally occurring

toxins and passes dangerous levels on to these top-level predators. This process is known as

bioaccumulation.

1. Why are the accidentally introduced zebra mussels referred to as an invasive species?

Open Ended

Regents Check

Refer to the previous question

2. Complete the food chain by filling in the correct organisms from the passage.

3. How has bioaccumulation resulted in the deaths of large numbers of birds even though the toxin level in the lake water is not high enough to make them sick?

4. Describe one possible effect that the increased deaths of the birds could have on the rest of the ecosystem.

Osprey