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1.  What you can do
2.  Water
3.  Ecology
4.  Amphibians
5.  Environmental Issues
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Wetland Curriculum Resource
Unit 5. Environmental Issues - Answers and Notes for Educators

5.2 Are You From Around Here?

  1. Students should understand that there can be serious consequences resulting from the introduction of exotic species. They can out compete more desirable species, and usually have no ecological value. There is a risk of introducing disease and harmful viruses. All of this results in a decline of habitat, or the decline of a more favourable species. The laws the students make up will vary, however, they should include penalties, fines, or even jail terms if these laws are broken.

5.3 All I Need Is The Air That I Breathe

  1. It caused the plant to wilt dramatically. Sulphur dioxide breaks down the waxy coating that helps prevent water loss.Human sources include: smelting, pulp and paper operations, coal burning, wood burning, and tobacco smoke.
  2. Natural sources include: decomposition (marshes and bogs), forest fires, and volcanoes.
  3. It reacts with oxygen in the atmosphere to form sulphuric acid, and then combines with water (precipitation) to form dilute sulphuric acid.
  4. Because the majority of sulphur dioxide is released by smelters, the problem has to be addressed at the source. It can be addressed 3 ways:
    1. go nuclear - reduces the need to burn coal
    2. develop more efficient scrubbers to remove the sulphur dioxide after combustion
    3. blow in lime (chalk dust) - neutralizes the acids, thus forming calcium nitrate (gypsum).
  5. Amphibians are most vulnerable in the earliest stages of their lives, during the egg and larvae stage. Since many amphibians spawn in pools of meltwater, the spring acid shock will often cause high mortality. The American toad suffers 100% egg mortality at pH 4.1, and the spotted salamander suffers 65% embryo mortality at pH 5.0.

5.4 Jack Listens To His Beans Talk

  1. Ideally, the beans will grow in conditions with a pH of 6.0 to 7.5. Although many minerals are more soluble in an acidic medium than in an alkaline one, if the soil becomes too acidic, the buildup of acid interferes with the plant's absorption of essential nutrients such as nitrates, phosphates, calcium, and potassium. Initially, it will affect the development of the seed. However, it also affects the plants' metabolism and growth processes. Knowing how acidic a soil is, can be used as a good indication of the nutrients a soil will provide and which nutrients a soil is most likely lacking.
  2. pH is the most important growth factor for plants as it controls the passing of nutrients across the cell membranes in the roots.
  3. The pitcher plant traps insects in its long cup-like leaves. It then releases digestive juices which break down the insect so it can obtain nitrogen.
  4. Because northern Ontario is shield rock and composed mostly of granite, it lacks the buffering capacity to neutralize the acids in acid rain or snow. Soils in southern Ontario are limestone-based and are able to neutralize acids.
  5. Research indicates, that when amphibians are subjected to prolonged periods of acidic conditions beyond their tolerable level, a suppression of their immune system occurs. Because amphibians live in an environment where much bacteria exists, they are at a higher risk of contracting diseases when their immune system has been weakened. Low pH can also affect fertilization and development of amphibian eggs.

5.5 Stormy Weather

  1. The pH of the samples can be accounted for by studying the weather maps from the local newspaper. Prevailing winds and weather patterns are the major contributing factors in determining the extent of the acid deposition in your area.
  2. By keeping the sample cold, it prevents any bacterial action from occurring which would drop the value of the pH.
  3. If the pH of the sampled precipitation is less than the normal value of 5.6 (remember that a decrease of one pH unit indicates a ten-fold increase in acidity), then there is ultimately added stress on aquatic ecosystems, trees, crops, and other materials such as cars, buildings, clothing, and statues in your area.
  4. Acid shock is caused by the large amounts of highly acidic water formed by stored pollutants, which are abruptly released when snow melts in the spring. The soils at this time are usually frozen and there is very little chance for the acids to be neutralized. This "shock" of acidity occurs at the most critical stage in an amphibian's life cycle. Many species of toads, frogs, and salamanders breed in temporary ponds formed by spring rains and melted snow. The eggs and developing embryos are exposed to the acids and deformity or death occurs.

5.6 Silence of the Contams

  1. These are organisms that serve as an early warning that an ecosystem is being degraded. Indicator organisms in a wetland include: algae, amphibians, and invertebrates.
  2. No. It is conceivable that organisms that thrive in polluted waters could also be found regularly in unpolluted waters. Relying solely on biological data can be misleading. But, it can be an indication that chemical tests are required for more accurate results.
  3. Bioaccumulation has its greatest effect at the top of the food chain. When toxic substances enter a food chain, they can accumulate in the fat or organs of animals. As contaminated organisms are eaten by others in a food chain, eventually the contaminants become more concentrated at the top of the food chain, sometimes to harmful levels.
  4. Since answers will vary, factors to be considered when rating include: possible sewage input, excess nutrient input, low water quality, lack of food, lack of shelter, eroded shoreline (from walking), litter or illegal dumping, location.
  5. Amphibians possess skin that can readily absorb the effects of environmental contamination. Amphibians are high in the food chain, and thus, reflect increasing levels of pollutants through biomagnification. When aquatic or terrestrial environments are under stress, the absence of amphibian populations usually indicates environmental change.

5.7 Wetlands Debate

  1. The purpose of panel members creating a cost/benefit analysis is to indicate, and weigh the pros and cons in the destruction of a wetland. By listing all benefits and costs, it paints a better picture as to whether or not the proposal should be approved.
  2. This answer obviously depends on the views expressed by the person involved. What is important here, is for the students to develop an opinion based on what they believe, and to develop respect and tolerance for those who have opposing points of view.


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