Info

figure 22-6

(a) Atmospheric CO2 concentration has been increasing in recent decades, as measured from the top of Mauna Loa, a large volcano in Hawaii. (b) Average global temperatures have been rising in a similar pattern. The graph shows the difference between recent short-term and past long-term temperature averages.

Acid Precipitation

Recall that in the global water cycle, water enters the atmosphere as vapor and returns to Earth's surface in the form of precipitation, such as rain or snow. Some air pollutants combine with water in the atmosphere and form acids. The result is precipitation that is acidic, or acid precipitation. Because organisms are adapted to the normal pH range of their environment, increased acidity of soil and water causes disease or death in trees, fish, and other organisms.

13 Intern*!CHVtâd

www.scilinks.org Topic: Environmental

Disruptions Keyword: HM60526

HlNKS.

Maintained by the National Science Teachers Association pP Fish-eating birds

Large fish

Small fish

Zooplankton and primary • producers

Zooplankton and primary • producers

Water figure 22-7

Red dots represent DDT.

In this example of biological magnification, the insecticide DDT runs off farms and into water sources, where it is taken up by algae. Then, the DDT passes up the food chain from the algae to zooplankton, to small fish, to bigger fish, and finally to predators such as eagles. DDT accumulates in fatty tissue, and its concentration increases as it moves up the food chain. In predatory birds, DDT can reach levels that cause the production of thin eggshells and leads to the death of offspring. The banning of DDT in the United States may have saved the bald eagle from extinction.

At the top of the food chain, DDT concentration has increased almost 10 million times.

Land and Water Pollution

Human activities can pollute land and water in several ways. Humans produce and must dispose of waste in the form of sewage and unused materials. Humans produce and use a variety of chemicals in industries, farms, ranches, stores, homes, schools, workshops, and cleaning services. Many of these chemicals are toxic, and some also cause cancer. Some chemicals are not directly harmful but cause damage to ecosystems if they are disposed of improperly or spilled by accident. Some chemicals enter ecosystems and undergo biological magnification, a process in which chemicals become more concentrated in an organism the higher on a food chain that organism is, as Figure 22-7 shows. As environmental problems are identified, governments increasingly regulate the manufacture, use, and disposal of chemicals.

DDT is stored in primary producers, such as algae.

DDT enters the water through ground water and runoff from land.

Was this article helpful?

0 0
Sirens Sleep Solution

Sirens Sleep Solution

Discover How To Sleep In Peace And Harmony In A World Full Of Uncertainty And Dramatically Improve Your Quality Of Life Today! Finally You Can Fully Equip Yourself With These “Must Have” Tools For Achieving Peace And Calmness And Live A Life Of Comfort That You Deserve!

Get My Free Ebook


Post a comment