Looking for a timely and concise way to integrate the grades 5-8 National Science Education Standards into a study of the impact of acid rain? Read on!

Middle school students have probably heard of “acid rain” and know it to be a bad thing. They might even know it comes from nitrogen and sulfur compounds emitted from industrial processes that chemically react with rain. The acid-compound products then eat away at buildings and statues. But the effects of acid rain are also seen in ecosystems.

Acid Rain Has a Disproportionate Impact on Coastal Waters, a press release from Woods Hole Oceanographic Institution, September 7, 2007, reports the work of a team of scientists who have predicted, modeled, observed, mapped, and described the quantity of dissolved carbon, nitrogen compounds, and sulfur compounds from acid rain in oceans along U.S. coastlines. Their study will be published by Proceedings of the National Academy of Sciences next week. Their findings indicate these compounds can be more concentrated in coastal waters as compared to the open ocean. The effects include lowering the pH, a trend which is predicted to continue such that by the end of this century, the pH in coastal waters will be 100 to 1,000 times lower than it is now. (The apparent wide range is accounted for by the logarithmic nature of the pH scale.)

Acid rain has several consequences for living systems, and marine organisms in particular. First, under relatively acid conditions, inorganic carbon is less easily harvested by aquatic organisms for photosynthesis, for example. Second, calcium, an element necessary for exoskeleton building, is also harder to sequester. Third, excess nitrogen enables algal blooms, which tend to consume many nutrients, making them unavailable for other organisms. Algal blooms also block sunlight, limiting photosynthesis to the surface only. Thus the potential for large impacts on marine ecosystems is at least three-pronged. By virtue of food chain and food web concepts, the impacts may eventually spread to areas outside of coastal zones, compounding the negative environmental impacts already documented in terrestrial ecosystems, such as erosion and soil nutrient depletion.

The press release underscores several domains of the National Science Education Standards. The first is Science as Inquiry Content Standard A, understandings about scientific inquiry. These scientists did not simply make a hypothesis and design a controlled experiment to test it as the scientific method suggests. Given the problem, that approach was inappropriate. Instead, as the standard states, they recognized:

Different kinds of questions suggest different kinds of scientific investigations. Some investigations involve observing and describing objects, organisms, or events; some involve collecting specimens; some involve experiments; some involve seeking more information; some involve discovery of new objects and phenomena; and some involve making models.

The second domain is Physical Science Content Standard B:

Substances react chemically in characteristic ways with other substances to form new substances (compounds) with different characteristic properties. In chemical reactions, the total mass is conserved. Substances often are placed in categories or groups if they react in similar ways; metals is an example of such a group.

The third domain is Life Science Content Standard C, Regulation and Behavior, Populations and Ecosystems:

All organisms must be able to obtain and use resources, grow, reproduce, and maintain stable internal conditions while living in a constantly changing external environment. . . . The number of organisms an ecosystem can support depends on the resources available and abiotic factors, such as quantity of light and water, range of temperatures, and soil composition. Given adequate biotic and abiotic resources and no disease or predators, populations (including humans) increase at rapid rates. Lack of resources and other factors, such as predation and climate, limit the growth of populations in specific niches in the ecosystem.

The fourth domain is Earth and Space Content Standard D:

Water is a solvent. As it passes through the water cycle it dissolves minerals and gases and carries them to the oceans. The atmosphere is a mixture of nitrogen, oxygen, and trace gases that include water vapor. The atmosphere has different properties at different elevations.

The fifth domain is Science in Personal and Social Perspectives Content Standard F:

Causes of environmental degradation and resource depletion vary from region to region and from country to country.

Here are some additional resources that are part of the NSDL Middle School Portal collection: Building a Bloom, National Oceanographic Data Center, and Top 20 Activities in Chemistry.

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Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.