Activity 9.1: Tropics versus the Poles

I. Draw the food webs

On separate sheets of paper, draw typical food webs for a coral reef ecosystem and an Antarctic ice-edge ecosystem. Include the following:

·  the organisms discussed in the episode

·  other organisms, based on your web search

·  highlight flows of energy from the sun through the food web to heat

·  highlight the recycling of carbon and nitrogen through the food web

·  indicate primary producers, primary consumers, higher trophic levels and decomposers

·  a list of the physical and chemical factors that may affect these food webs

Use your textbook, the video episode and the web sites below to identify the major organisms and their links. As well, use these web sites to better understand and depict the major pathways of energy and matter

Recommended web sites:

The Ecology of Coral Reefs

http://www.soc.soton.ac.uk/GDD/hydro/atmu/ecology/menu.html

Coral Reef Ecosystem

http://www.reefrelief.org/coralreef/

Coral Reef Ecology

http://www.fcsc.usgs.gov/Coral_Reef_Ecology/coral_reef_ecology.html

Coral Reefs Resource Guide

http://www.aquarium.usm.edu/coralreef/

Antarctica – Wildlife

http://www.antarctica.ac.uk/About_Antarctica/Wildlife/index.html

Classroom Antarctica

http://classroomantarctica.aad.gov.au/

Arctic Ocean Ecosystems

http://envirosphere.ca/pdf/arctic.pdf

Arctic Sea Ice: Channels of Life

http://oceanexplorer.noaa.gov/explorations/02arctic/background/sea_ice/sea_ice.html

The Ecosystem and Food Web of the Antarctic Peninsula

http://www.literacynet.org/polar/pop/html/project-ecosystem.html

II. Compare and contrast

Now that you have a picture of the food webs of these ecosystems, compare and contrast their similarities and differences. Use the table below to guide your thinking. Then complete the critical thinking questions below.

Characteristic / Coral Reef Ecosystem /

Polar Ecosystem

Average water temperature?
Average day length?
Abundance of dissolved nutrients?
Effects of seasonal changes in physical and chemical factors on food web?
Who are the primary producers?
Who are the major consumers?
Who are the top predators?
Who are the decomposers and detritivores?
How does the ecosystem export or retain organic matter?
How does man affect this ecosystem?

III. Critical Thinking Questions

1. In what ways are the flows of energy and cycling of matter similar in coral reef and polar ecosystems? In what ways are they different?

2. How do fluctuations in the external environment—the physical and chemical factors—govern the flow of energy and cycling of matter in these ecosystems?

3. Coral reefs are often called steady-state systems while ice-edge ecosystems are pulsed or non-equilibrium systems. How do these characteristics, i.e. steady-state or non-equilibrium, allow or not allow these ecosystems to adapt to changes induced by humans, such as global warming? (This is a tough question but take your best shot. There’s no right answer here but this question does test your understanding of these ecosystems and the effects of human activities.)