BIOLOGY [ES] * WEATHER/CLIMATE [EaS]
Objectives
After viewing the video and participating in one or more of the Hands-On Activities, students will be able to:
• describe and model the Antarctic marine food chain, and compare and contrast this food web to those found elsewhere
• model key aspects of the process of photosynthesis
• simulate the scientific instrumentation which enables Antarctic researchers to sample the water column at different depths
Program Description
This video begins the 3 program sub-set of PASSPORT TO ANTARCTICA focusing on life in the most extreme environment on Earth. These 3 programs allow you to cover a substantial number of the benchmarks found in Science Standard 4, "Knows about the diversity and unity that characterize life" (Project 2061 Benchmarks for Science Literacy, page 101); Standard 7, "Understands how species depend on one another and on the environment for survival" (Project 2061, page 115); and Science Standard 8, "Understands the cycling of matter and flow of energy through the living environment" (Project 2061, page 118.) Activities suggested for these 3 programs also allow students to simulate some of the instruments used by the researchers. The combination of video, Activities and online extensions allow you to introduce and explain photosynthesis, adaptation through natural selection, the concept of species, and the workings of an entire ecosystem in a dramatic and memorable way.
Most plants and animals in Antarctica (other than tiny nematodes in the Dry Valleys and microbes at the Pole) rely on the ocean, and can be found close to the coast. Program 3 looks in detail at the Antarctic marine ecosystem, and traces this unique and fascinating food web from small to large.
• "The Antarctic Food Web" (04:03) Life on land is subject to fierce winds and extreme low temperatures. The Southern Ocean, however, remains in a constant, narrow range from minus 2 to plus 2 degrees C. almost all year. It's the annual cycle of months of darkness followed by months of light that sets the cycle of life in motion. This segment introduces key links in the food chain from Sun to ice algae, phytoplankton (microscopic free-floating plants), tiny shrimp-like krill, penguins, skuas, seals and whales. It presents the players we'll see acting out their roles as "producers," "consumers" and "decomposers" in the drama of life in the Antarctic.
• "Studying the Marine Ecosystem" (08:45) Robin Ross from U.C. Santa Barbara (whose team we saw in program 1) heads the "Prey" portion of the Palmer Long-Term Ecological Research Project, LTER. The segment documents both the research tools she uses and the creatures which the innovative instrumentation can show us. "BOPS," the Bio-Optical Profiling System, brings water up from different depths. (See the Hands-On Activities below for ways in which students can design and construct "mini-BOPS" in class.) Ross describes phytoplankton as the "grasses" of the Antarctic, and says that light "and some of the same factors that control the growth of the grasses on your lawn" also drives their annual cycle. We see the stormy weather in which Dave Karl, from the University of Hawaii, has to deploy and retrieve the sediment traps which are used to trace the minerals and other chemical constituents of the ocean. Ross then walks students "up" the food web, describing krill-perhaps the most numerous species on Earth-as the small but all important "cows," or grazers, of the Southern Ocean, and the "keystone" species on which all the higher life forms depend. We see how Ross uses acoustic sounding and nets to document the position and number of krill. Next we meet Bill Fraser and Donna Patterson who head the "Seabird" portion of the LTER. They attach mini-radio transmitters to Adelie penguin to track how far the birds have to travel in search of food for themselves and their hungry chicks. Fraser notes that it's the extent and placement of sea ice that affects every creature we've seen, from plankton to penguins. Lastly we visit some of the small islands close to Palmer Station as we go on "rounds" with Patterson to check up on nests of giant petrels. These birds are long-distance scavengers, flying all the way to South Africa, Australia and New Zealand in search of dead whales and other nourishment for their single, large chick. The program concludes by noting that once humans almost made many species of seals and whales extinct: though krill may seem so abundant, perhaps we need to remember just how dependent all links in the Antarctic food chain are on these small creatures, and use research programs such as LTER to guide our actions.
