Description

Discussion: Natural Cycles and the Human Impact

Focus on Biogeochemical Cycles: Challenges and Solutions

Have you ever wondered where the food that you consume, the fresh water that you drink, or the air that you breathe comes from? What is the history behind the essential inputs of our lives and what can we do to better manage them?

Over geological time and evolutionary history, the interplay between different organisms and the physical makeup of the natural world has resulted in the emergence of relatively stable patterns of nutrient and chemical flows. Food webs, for instance, describe how energy and nutrients flow through the various organisms that make up an ecosystem. Each organism’s life cycle plays out within a network of relationships with both predators and prey. Biogeochemical cycles refer to how important chemical elements cycle through the ecosphere, connecting all of life and the physical substrate within which they live. Examples of important biogeochemical cycles include the carbon cycle, the nitrogen cycle, the phosphorus cycle, the oxygen cycle, and the water cycle. These cycles underlie the welfare of all life on earth.

Human activity has disrupted and impacted the natural flows of chemicals and nutrients in our environment in many different ways. Unfortunately our disruption of ecological cycles has had negative consequences for the wellbeing of humans as well as other life forms.

In this Discussion you will describe a biogeochemical cycle or nutrient flow of your choice, explain how human activity has impacted the cycle, describe one or more problems caused by our impact, and reflect on what we might do to improve or mitigate our impact.

To prepare for this Discussion

• Review the Interactive Unit for this week and the links posted by your professor, and then conduct your own independent research to support your post.
• Select a particular nutrient flow or biogeochemical cycle to focus on in your primary research-based post this week. Consider some of the benefits or services provided by this natural flow or cycle.
• Consider the ways that humans impact the cycle of flow of your choice and how this impact challenges the health of humans and other life forms.
• Reflect on what can be done to improve or mitigate our impact either individually or as a society.

With these thoughts in mind, complete the following:

Spark Response Post (20 points):

By Day 2

Post a two or more paragraph response to the Discussion Spark posted by your professor on Monday (Day 1) in the week 2 discussion forum. Notice that the responses to the Discussion Spark, the primary research-based Discussion Topic, and your colleagues or professor will be graded together.

Primary Research-based Post (35 points):

By Day 4

Post: four or more paragraphs in which you:

1. briefly describe a biogeochemical cycle or nutrient flow of your choice,
2. explain at least one way that humans impact this flow and why this is important to the health of humans or other life forms; and
3. reflect on at least one measure to improve our impact (either as individuals or as a society). If other people have already presented substantive posts on a given cycle, you might consider treating a different cycle. Cite at least two authoritative reference sources beyond the Interactive Unit for this week to support your presentation in this post.

Read a selection of your colleagues’ and professor’s postings.

Response Posts (15 points):

By Day 5 and 7

Respond by to at least two of your colleagues’ or professor’s postings in a substantive manner, meaning a minimum of 1 full paragraph. Simple “I agree,” “Good post,” or one-line question posts are not enough for full credit. Be substantive as you engage your colleagues.

Return to this Discussion in a few days to read the responses to your initial research- based posting. Note what you have learned and/or any insights you have gained as a result of the comments your colleagues made.

Research Requirement: Be sure to support your ideas by connecting them to authoritative scientific information sources. Every week you are expected to conduct independent research (beyond the course resources). Cite your research sources and include links whenever possible.