Global Climate Change and the Antarctic Ecosystem

(adapted from A Cooperative Classroom, The Science Teacher, September, 2007)

Background:

Climatologists have observed changes in average air temperatures on the Antarctic Peninsula since 1947.

We think this might be occurring because of an increase greenhouse gases, but we are unsure of the impacts on the Antarctic ecosystem. Your team’s job is to describe the interconnected effects of warming on Antarctica’s living and nonliving systems.

Your Role:

Each member of your team will act as a specialist who has investigated a different aspect of the ecosystem on the Antarctic Peninsula.

· Fisheries Biologist – Scientist who studies fish and their prey. Collects data on krill population densities during research vessel cruises.

· Marine Ecologist – Scientist who studies the relationships between organisms and their ocean environments. Uses visual surveys, diet analysis, and satellite tracking to collect data on a variety of organisms, including penguins.

· Meteorologist – Scientist who studies the weather. Uses automatic weather stations and visual observation of the skies to collect data on precipitation, temperature, and cloud cover.

· Oceanographer – Scientist who studies the ocean. Uses satellite imagery, underwater sensors, and manual measurements of sea ice thickness to collect data on sea ice conditions and ocean temperature.

· Ornithologist – Scientist who studies birds. Uses visual surveys (from ship and on land), diet analysis, and satellite tracking to collect data on penguins.

Activity:

Your task is to discuss and analyze your data as a team, collectively describe your findings, and then present them to the whole group. Your presentation will take the form of a flowchart that shows the cause-and-effect relationships between a variety of living and nonliving components of the ecosystem. Your flowchart should include each of the following elements:

· Adelie Penguin Population

· Air Temperature

· Chinstrap Penguin Population

· Krill Density

· Sea Ice Extent; and

· Winter Snow

How to Construct a Flowchart (an example): Events have causes, sometimes simple, sometimes multifaceted. A major activity of science is investigating and explaining causal relationships that exist in a system. In an ecosystem for example, if a predator population increases, it may cause a prey population to decrease.

Likewise, if the food supply increases, it may cause the prey population to increase.

Your flowchart should show each of the six boxes listed above, along with several interconnecting arrows which represent the cause-and-effect relationships you’ve discovered and identified.

Marine Ecologist II: You have been studying three colonies of Adelie Penguins at two different locations in Antarctica. Adelie Penguins require bare stony ground to build their nests, and a combination of sea ice and open water to find food, mostly krill.

One colony of Adelie Penguins is on Anvers Island (Latitude 64o 33’ S, Longitude 63o 35’ W), near the northern tip of the Antarctic Peninsula. Its population changes are shown in the graph below.

The other two colonies of Adelie Penguins are located further south on Ross Island (Latitude 77o 30’ S, Longitude 168o 00’ E) where warming temperatures have begun to slowly break up the sea ice. One colony is on Cape Bird, and the other on Cape Royds. Their population changes are shown in the graph below.

Data taken from http://www.penguinscience.com/clim_change.php

Going Farther: Identifying a Positive Feedback Loop

Feedback is a process in which a change in one quantity in a system causes a change in a second quantity. The change in the 2nd quantity then causes a change in the 1st quantity. If the change in the first quantity is reduced, the feedback is called negative. If the change in the first quantity is amplified, the feedback is positive.

An example of a negative feedback loop is a room thermostat. When a room gets cooler, the thermostat sends a signal which causes the furnace to produce heat. This causes the room to become warmer, and the thermostat stops sending a signal to the furnace.

Image adapted from Pearson Education, Inc.

An example of a positive feedback loop is a cattle stampede. One animal becomes panicked and starts running. This causes additional animals to become panicked and start running. The result is the overall level of panic gets amplified.

Image adapted from Wikipedia.com

In the space below, design a flowchart which illustrates the positive feedback loop that exists between Antarctic Air Temperature and the amount of Sea Ice present.