Expedition to the Deep Slope 2007 Monsters of the Deep [adapted from the 2002 Gulf of Mexico Expedition] FOCUS AUDIO/VISUAL MATERIALS Predator-prey relationships between cold-seep None communities and the surrounding deep-sea envi- ronment TEACHING TIME Two 45-minute class periods, plus time for indi- GRADE LEVEL vidual group research 7-8 (Life Science) SEATING ARRANGEMENT FOCUS QUESTION Groups of four students What deep-sea predators may visit cold-seep communities in search of food? MAXIMUM NUMBER OF STUDENTS 30 LEARNING OBJECTIVES Students will be able to describe major features KEY WORDS of cold seep communities, and list at least five Cold seeps organisms typical of these communities. Methane hydrate ice Chemosynthesis Students will be able to infer probable trophic Brine pool relationships among organisms typical of cold- Polychaete worms seep communities and the surrounding deep-sea Vestimentiferans environment. Chemosynthetic bacteria Mussels Students will be able to describe in the process of Sea stars chemosynthesis in general terms, and will be able Eels to contrast chemosynthesis and photosynthesis. Squat lobsters Snails Students will be able to describe at least five Isopods deep-sea predator organisms. Spider crabs Anglerfishes MATERIALS Pelican eel 5 x 7 index cards Pancake bat fish Drawing materials Viperfish Corkboard, flip chart, or large poster board Fangtooth Squids Football fish 1 Expedition to the Deep Slope 2007 – Grades 7-8 (Life Science) Focus: Predator-prey relationships oceanexplorer.noaa.gov Hatchet fish Vestimentifera have been included in the phylum Trophic level Annelida). Pogonophora means “beard bear- ing,” and refers to the fact that many species in BACKGROUND INFORMATION this phylum have one or more tentacles at their Cold seeps are areas of the ocean floor where anterior end. Tentacles of vestimentiferans are gases (such as methane and hydrogen sulfide) bright red because they contain hemoglobin and oil seep out of sediments. These areas are (like our own red blood cells). Vestimentiferans commonly found along continental margins, and can grow to more than 10 feet long, sometimes are home to many species of organisms that have in clusters of millions of individuals, and are not been found anywhere else on Earth. Unlike believed to live for more than 100 years. They biological communities in shallow-water ocean do not have a mouth, stomach, or gut. Instead, habitats, cold-seep communities do not depend they have a large organ called a trophosome that upon sunlight as their primary source of energy. contains chemosynthetic bacteria. Hemoglobin in Instead, these communities derive their energy the tubeworm’s blood absorbs hydrogen sulfide from chemicals through a process called chemo- and oxygen from the water around the tentacles, synthesis (in contrast to photosynthesis in which and then transports these raw materials to bac- sunlight is the basic energy source). Some che- teria living in the trophosome (the tentacles also mosynthetic communities have been found near absorb carbon dioxide, which is also transported underwater volcanic hot springs called hydrother- to the bacteria). The bacteria produce organic mal vents, which usually occur along ridges sepa- molecules that provide nutrition to the tubeworm. rating the Earth’s tectonic plates. Visit http://www. Similar relationships are found in clams and mus- pmel.noaa.gov/vents and http://www.divediscover.whoi.edu/vents/ sels that have chemosynthetic bacteria living in index.html for more information and activities on their gills. A variety of other organisms are also hydrothermal vent communities. found in cold-seep communities, and probably use tubeworms, mussels, and bacterial mats as Typical features of the cold seep chemosynthetic sources of food. These include snails, eels, sea communities that have been studied so far include stars, crabs, isopods, sea cucumbers, and fishes. mounds of frozen crystals of methane and water Specific relationships between these organisms called methane hydrate ice that are home to have not been well-studied. polychaete worms. Brine pools, containing water four times saltier than normal seawater, have Recently, increasing attention has been focused also been found. Researchers often find dead fish on cold seeps in the Gulf of Mexico, an area that floating in the brine pool, apparently killed by the produces more petroleum than any other region high salinity. The base of the food chain in cold in the United States. Responsibility for managing seep communities is chemosynthetic bacteria that exploration and development of mineral resources are able to obtain energy from some of the chem- on the Nation’s outer continental shelf is a central icals seeping out of the ocean floor. Bacteria may mission of the U.S. Department of the Interior’s form thick bacterial mats, or may live in close Minerals Management Service (MMS). In addi- association with other organisms. tion to managing the revenues from mineral resources, an integral part of this mission is to One of the most conspicuous associations protect unique and sensitive environments where exists between chemosynthetic bacteria and these resources are found. MMS scientists are large tubeworms that belong to the group particularly interested in finding deep-sea che- Vestimentifera (formerly classified within the phy- mosynthetic communities in the Gulf of Mexico, lum Pogonophora; recently Pogonophora and because these are unique communities that often 2 Expedition to the Deep Slope 2007 – Grades 7-8 (Life Science) oceanexplorer.noaa.gov Focus: Predator-prey relationships include species that are new to science and http://www.bio.psu.edu/hotvents for a virtual tour of a whose potential importance is presently unknown. hydrothermal vent community. In addition, the presence of these communities often indicates the presence of hydrocarbons at 2. Lead a discussion of deep-sea chemosynthetic the surface of the seafloor. communities. Contrast chemosynthesis with photosynthesis: In both processes, organisms The 2006 Expedition to the Deep Slope was build sugars from carbon dioxide and water. focused on discovering and studying the sea floor This process requires energy; photosynthesiz- communities found near seeping hydrocarbons ers obtain this energy from the sun, while che- on hard bottom in the deep Gulf of Mexico. mosynthesizers obtain energy from chemical The sites visited by the Expedition were in areas reactions. Point out that there are a variety of where energy companies will soon begin to drill chemical reactions that can provide this kind of for oil and gas. A key objective was to provide energy. Contrast hydrothermal vent communities information on the ecology and biodiversity of with cold-seep communities. these communities to regulatory agencies and energy companies. Dives by scientists aboard Review the concepts of food chains and food the research submersible ALVIN revealed that webs, including the concept of trophic levels hydrocarbons seepage and chemosynthetic com- (primary producer, primary consumer, second- munities were present at all ten sites visited by the ary consumer, and tertiary consumer). Expedition. The most abundant chemosynthetic organisms seen were mussels and vestimentiferan 3. Assign each student group one or more of the tubeworms. Expedition to the Deep Slope 2007 following organisms to research: is focused on detailed sampling and mapping of Cold-Seep Groups: four key sites visited in 2006, as well as explor- • Polychaete worms ing new sites identified from seismic survey data. • Vestimentiferans • Chemosynthetic bacteria Cold-seep communities are surrounded by a • Mussels much larger deep-sea environment that contains a • Sea stars variety of unusual creatures with names like viper- • Eels fish, football fish, and vampire squid. Very little • Squat lobsters is known about interactions between cold-seep • Snails communities and organisms from the surrounding • Isopods deep-sea. It seems likely, though, that deep-sea • Spider crabs predators visit cold-seep communities in search of food, since these communities produce large Deep-Sea Groups: amount of biological material. This activity focus- • Anglerfishes es on cold-seep communities and deep-sea preda- • Pelican eel tors that may use these communities for food. • Pancake bat fish • Viperfish LEARNING PROCEDURE • Fangtooth 1. To prepare for this lesson, visit http://oceanexplorer. • Squids noaa.gov/explorations/07mexico/welcome.html for informa- • Football fish tion about Expedition to the Deep Slope 2007. • Hatchet fish You may want to visit http://www.bio.psu.edu/cold_seeps for a virtual tour of a cold seep community, and 3 Expedition to the Deep Slope 2007 – Grades 7-8 (Life Science) Focus: Predator-prey relationships oceanexplorer.noaa.gov In addition to written reference materials (ency- 5. Lead a discussion of the food web the students clopedia, periodicals, and books on the deep- have created. Which groups show the great- sea), the following Web sites contain useful est variety of anatomical types and feeding information: strategies? Which groups are responsible for http://www.bio.psu.edu/cold_seeps primary production? What would the students http://www.pbs.org/wgbh/nova/abyss/life/bestiary.html infer about the relative abundance of each tro- http://biodidac.bio.uottawa.ca/ phic level? In the simplest analysis, organisms http://www.fishbase.org/search.cfm at lower trophic levels (primary producers and http://www.learningdemo.com/noaa/ Lesson 5, primary consumers)