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Animations
(Animation Requirements)

• Ecosystem Organization
• Hydrologic (Water) Cycle
• Carbon Cycle I
• Carbon Cycle II
• Nitrogen Cycle I
• Nitrogen Cycle II
• Four Seasons
• Distribution of Solar Energy
• Global Air Circulation
• Global Wind Circulation
• Rain Shadow Effect
• Formation of a Rain Shadow
• El Niño Southern Oscillation
• Deoxygenation of Lakes
• Lake Stratification

Ecosystem Destruction. Human impact on the world's ecosystems is harming species in increasingly severe ways. In many cases the exact nature of the damage is not clearly understood. The reasons for amphibian decline have only emerged after a major worldwide research effort. The case for global warming resulting from increased release of carbon dioxide into the atmosphere as a result of human activity, on the other hand, seems clearcut.

1. Research is revealing complex reasons for the global decline in amphibians.
2. Global warming is a problem that is not going to be solved by ignoring it.
3. The problem of exploding urban deer populations has no solutions that please everybody.
4. Migrating woodland songbirds are in steep decline due to habitat loss.

The Global Environmental Challenge
The current world population of more than 6 billion people is placing severe strains on our earth's ability to sustain and support so many people. While the worldwide average birthrate has remained fairly constant for the last 300 years at 25 to 30 births per year per 1,000 people, the death rate has fallen from about 29 per year per 1000 people to about 19 per year per 1,000 people. This difference between birth and death rates produces an annual worldwide increase of approximately 1.4%. The rate may seem small, but it doubles the world's population every 39 years! The environmental problems that haunt the new century — global warming, ozone depletion, acid rain, chemical pollution — all are a direct result of this explosion of human population growth, the engine which fuels consumption, "development" of third-world resources, and the environmental destruction this economic activity fosters. Perhaps the most serious harm concerns loss of nonrenewable resources, such as top soil, groundwater, and biodiversity. Current levels of consumption of these resources are not sustainable, and replenishment can take many centuries.

Why Does Contamination of a Coastal Salt Marsh with Diesel Fuel Lead to Increased Microalgal Biomass?
In shallow coastal waters microscopic algae ("microalgae") are an important food source for the many small animals that live in the sediment. However, the trophic interactions between the microalgae and their consumers are not well understood. As with any food web, a balance is reached between producers and consumers, but it is not clear what factors directly or indirectly influence that balance. We need to understand these food web relationships to properly assess the potential effects of pollution or environmental changes on the benthic community. Kevin Carman, John Fleeger, and Steven Pomarico, all from Louisiana State University, Baton Rouge, have studied the affects of diesel fuel-contaminated sediments on the meiofaunal (primarily copepods and nematodes) and microalgae food web of a coastal salt marsh. The researchers set up microcosms in the laboratory using intact natural sediments and salt water. They then exposed the microcosms to various levels of diesel fuel contamination, and observed the effects on the levels of microalgae and meiofauna. Interestingly, the levels of microalgae seem to increase with pollution, while meiofauna decrease.