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Let's Make a Tubeworm!

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Let's Make a Tubeworm! Gulf of Mexico Exploration Let’s Make a Tube Worm! FOCUS Polychaete worm Symbiotic relationships in cold-seep communities Bacteria Symbiotic GRADE LEVEL Trophosome 5-6 Life Science Hemoglobin Organic FOCUS QUESTION How are deep-sea tubeworms adapted for a symbi- The words listed as key words are integral to the otic relationship that allows them to survive? unit. There are no formal signs in American Sign Language for any of these words and many are LEARNING OBJECTIVES difficult to lipread. Having the vocabulary list on Students will be able to describe the process of the board as a reference during the lesson will be chemosynthesis in general terms, and will be able extremely helpful. Also give the list as a handout to contrast chemosynthesis and photosynthesis. to the students to refer to after the lesson. Students will be able to describe major features of Taking some time to introduce some of the cold seep communities, and list at least five organ- Background Information will be of great use later isms typical of these communities. as the students attempt to complete the activity in Part 4. Have the students act as one group for Parts Students will be able to define symbiosis and will 3 and 4. An alternative to the written report, which be able to describe two examples of symbiosis in might be difficult or time consuming, is to have the cold seep communities. students make a video or oral presentation. Students will be able to describe the anatomy of MATERIALS vestimentiferans, and explain how these organisms (If posters are to be made) poster materials (bris- obtain their food. tol board, markers) (If models are to be made) cardboard tubes (mail- ADDITIONAL INFORMATION FOR TEACHERS OF DEAF STUDENTS ing tube or paper towel roll), colored markers, In addition to the words listed as key words, the pipe cleaners (to simulate tentacles), modelling following words should be part of the list. clay, paper and glue (to make a model tropho- Photosynthesis some) Symbiosis Hydrothermal vent AUDIO/VISUAL MATERIALS Hydrocarbon None Sediments 1 Gulf of Mexico Exploration - Grades 5-6 (Life Science) Gulf of Mexico Exploration - Grades 5-6 (Life Science) Focus: Deep-sea hobitats oceanexplorer.noaa.gov oceanexplorer.noaa.gov Focus: Deep-sea habitats TEACHING TIME Other deep-sea chemosynthetic communities are One or two 45-minute class periods found in areas where hydrocarbon gases (often methane and hydrogen sulfide) and oil seep out of SEATING ARRANGEMENT sediments. These areas, known as cold seeps, are Groups of four students commonly found along continental margins, and (like hydrothermal vents) are home to many species of MAXIMUM NUMBER OF STUDENTS organisms that have not been found anywhere else 30 on Earth. Typical features of communities that have been studied so far include mounds of frozen crystals KEY WORDS of methane and water called methane hydrate ice, Cold seeps that are home to polychete worms. Brine pools, con- Methane hydrate ice taining water four times saltier than normal seawater, Chemosynthesis have also been found. Researchers often find dead Brine pool fish floating in the brine pool, apparently killed by Vestimentifera the high salinity. Trophosome Plume As is the case with hydrothermal vents, chemosyn- Vestimentum thetic bacteria are also the base of the food web in Trunk cold seep communities. Bacteria may form thick bac- Tube terial mats, or may live in close association with other Opisthosome organisms. These associations are examples of sym- biotic relationships in which both organisms benefit BACKGROUND INFORMATION from the association (in contrast to parasitic relation- One of the major scientific discoveries of the last 100 ships in which one organism benefits and the other years is the presence of extensive deep-sea com- is harmed). One of the most interesting and unusual munities that do not depend upon sunlight as their symbiotic relationships exists between chemosynthetic primary source of energy. Instead, these communities bacteria and large tubeworms that belong to the derive their energy from chemicals through a process group Vestimentifera (formerly classified within the called chemosynthesis (in contrast to photosynthesis phylum Pogonophora; recently Pogonophora and in which sunlight is the basic energy source). Some Vestimentifera have been included in the phylum chemosynthetic communities have been found near Annelida). Pogonophora means “beard bearing,” underwater volcanic hot springs called hydrothermal and refers to the fact that many species in this phy- vents, which usually occur along ridges separating lum have one or more tentacles at their anterior end. the Earth’s tectonic plates. Hydrogen sulfide is abun- Tubeworms that live in the vicinity of hydrothermal dant in the water erupting from hydrothermal vents, vents and cold seeps are called vestimentiferans, and is used by chemosynthetic bacteria that are the and their tentacles are bright red because they base of the vent community food chain. These bac- contain hemoglobin (like our own red blood cells). teria obtain energy by oxidizing hydrogen sulfide to Vestimentiferans can grow to more than 10 feet sulfur: long, sometimes in clusters of millions of individuals, and are believed to live for more than 100 years. CO2 + 4H2S + O2 > CH2O + 4S +3H2O (carbon dioxide plus sulfur dioxide plus oxygen They do not have a mouth, stomach, or gut. Instead, yields organic matter, sulfur, and water). Visit http: they have a large organ called a trophosome, that //www.pmel.noaa.gov/vents/home.html for more information contains chemosynthetic bacteria. Hemoglobin in the and activities on hydrothermal vent communities. tubeworm’s blood absorbs hydrogen sulfide and oxy- gen from the water around the tentacles, and then 2 3 Gulf of Mexico Exploration - Grades 5-6 (Life Science) Gulf of Mexico Exploration - Grades 5-6 (Life Science) Focus: Deep-sea hobitats oceanexplorer.noaa.gov oceanexplorer.noaa.gov Focus: Deep-sea habitats transports these raw materials to bacteria living in 3. Have each student group create a poster or three- the trophosome. The bacteria produce organic mol- dimensional model of a tubeworm. A portion of ecules that provide nutrition to the tubeworm. the poster or model should be in cut-away form so that internal structures can be seen. The fol- Similar symbiotic relationships are found in clams lowing structures should be included: and mussels that have chemosynthetic bacteria liv- • Plume (including red color to indicate hemo- ing in their gills. A variety of other organisms are globin) also found in cold seep communities, and probably • Vestimentum use tubeworms, clams, mussels, and bacterial mats • Trophosome (including symbiotic bacteria) as sources of food. These organisms include snails, • Trunk eels, sea stars, crabs, lobsters, isopods, sea cucum- • Tube bers, and fishes. Specific relationships between • Opisthosome these organisms have not been well-studied. 4. Have each group prepare a written report that The Gulf of Mexico contains the largest reservoir of includes: fossil fuel in the continental U.S., and the geology • A description of the function of each of the of the area has been intensively studied for more organs or structures listed above; than 50 years. While cold seep communities were • A description of the symbiotic relationship discovered in the Gulf in 1984, the biology of these between the tubeworm and chemosynthetic communities has been studied at only three sites bacteria; less than 20 km apart. Exploring for new cold seep • An explanation of how the tubeworm obtains sites and studying the biology and ecology of the its food organisms that live there is the focus of the Ocean • A discussion of how this symbiotic relationship Exploration 2002 Gulf of Mexico Expedition. supports other organisms in the cold seep food web, and what some of these organisms might This activity focuses on the unusual anatomy and be. ecology of vestimentiferans. THE BRIDGE CONNECTION LEARNING PROCEDURE www.vims.edu/BRIDGE/vents.html 1. Lead a discussion of deep-sea chemosynthetic communities. Contrast chemosynthesis with THE “ME” CONNECTION photosynthesis: In both processes, organisms Have students write a short essay on symbiotic rela- build sugars from carbon dioxide and water. tionships that are important in their own lives. This process requires energy; photosynthesizers obtain this energy from the sun, while chemosyn- CONNECTIONS TO OTHER SUBJECTS thesizers obtain energy from chemical reactions. English/Language Arts, Earth Science Contrast hydrothermal vent communities with cold-seep communities. Visit http://www.bio.psu.edu/ EVALUATION cold_seeps for a virtual tour of a cold seep commu- Models or posters and the accompanying written nity, including several images of tubeworms. reports can be evaluated on the basis of the extent to which the required elements are included and 2. Have students visit http://www.cham.montefiore.org/links/ upon the quality of the written discussions. pbs/wgbh/nova/abyss/life/tubewormsans.html to find an illustration of tubeworm anatomy and explana- EXTENSIONS tions of what each body part does. Have students draw a cold seep food web that 2 3 Gulf of Mexico Exploration - Grades 5-6 (Life Science) Focus: Deep-sea hobitats oceanexplorer.noaa.gov includes at least six organisms representing pri- Content Standard D: Earth and Space Science mary producers and consumers. • Structure of the Earth system RESOURCES FOR MORE INFORMATION http://oceanexplorer.noaa.gov – Follow the Gulf of Mexico Paula
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