bio 8.2

what is the best route for mercury to enter the food web

Coal-burning emissions -> deposition -> ocean -> plankton -> fishes

The graph above shows the effect of sewage on biological oxygen demand (BOD) and dissolved oxygen(DO) in a flowing stream. The smallest fish populations will most probably be found at point?

E

The use of nitrogen-based fertilizers in the Midwestern United States is a major contributing factor to what?

Hypoxia in the Gulf of Mexico

Scientists are interested in measuring the effect of pollution on the water quality of a stream. They will use observations of various bottom-dwelling insects, or macroinvertebrates, collected in the stream as indicators of the physical, chemical, and biological conditions within the stream. Why can macroinvertebrate sampling be used to assess the overall health of a stream?

Macroinvertebrates live in an aquatic ecosystem for a long enough time to show the chronic effects of pollutants, and many tend to remain in the same area throughout their life span.

all of the following are considered heavy metal toxins exept...

Potassium

Which law mandates the restoration and maintenance of the chemical, physical, and biological integrity of the nation's waters?

clean water act

Coral bleaching can be hazardous to some fish species because

decomposition of corals can lead to ocean acidification

The release of a large amount of sewage and other organic wastes into a river would likely result in a sharp increase in what?

increase in the biological oxygen demand

In a river ecosystem, dissolved oxygen concentrations drop quickly downstream from a point-source input of organic matter into the river. This effect is due to what?

increasing bacterial activity as organic matter decays

What are three common methods employed in the cleanup of oil spills?

large floating booms, skimmer boats, and genetically engineered bacteria

What is phytoremediation?

the use of plants to absorb and accumulate toxic materials from the soil

What is a measure of the amount of suspended material in water?

turbidity