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Cool Corals [Adapted from the 2003 Life on the Edge Expedition]

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Cool Corals [Adapted from the 2003 Life on the Edge Expedition] Expedition to the Deep Slope 2007 Cool Corals [adapted from the 2003 Life on the Edge Expedition] FOCUS SEATING ARRANGEMENT Biology and ecology of Lophelia corals Groups of 4-6 students GRADE LEVEL MAXIMUM NUMBER OF STUDENTS 9-12 (Life Science) 30 FOCUS QUESTION KEY WORDS What do scientists know about the basic biology Continental shelf and ecology of Lophelia corals? Continental slope Hard bottom LEARNING OBJECTIVES Lophelia pertusa Students will be able describe the basic morphol- Deep-water coral ogy of Lophelia corals and explain the signifi- Trawling cance of these organisms. BACKGROUND INFORMATION Students will be able to interpret preliminary The Gulf of Mexico produces more petroleum observations on behavior of Lophelia polyps, and than any other region in the United States, even infer possible explanations for these observations. though its proven reserves are less than those in Alaska and Texas. Since the 2005 disrup- Students will be able to explain why biological tion in Gulf of Mexico oil production caused by communities associated with Lophelia corals are Hurricane Katrina, efforts have intensified to find the focus of major worldwide conservation efforts. more crude oil and drill more wells. Responsibility for managing exploration and development of MATERIALS mineral resources on the nation’s outer continental Copies of “Preliminary Studies of Lophelia pertu- shelf is a central mission of the U.S. Department sa Polyp Behavior,” one for each student group of the Interior’s Minerals Management Service (MMS). In addition to managing the revenues AUDIO/VISUAL MATERIALS from mineral resources, an integral part of this Chalk board, marker board, or overhead pro- mission is to protect unique and sensitive environ- jector with transparencies and markers for ments where these resources are found. group discussion Cold seeps are areas of the ocean floor where TEACHING TIME gases (such as methane and hydrogen sulfide) One to one-and-a-half 45-minute class periods, and oil seep out of sediments. These areas are plus time for research commonly found along continental margins, and 1 Expedition to the Deep Slope 2007 – Grades 9-12 (Life Science) Focus: Biology and ecology of Lophelia corals oceanexplorer.noaa.gov are home to many species of organisms that Hard or “live” bottom habitats support diverse have not been found anywhere else on Earth. biological communities that include valuable fish Unlike biological communities in shallow-water and invertebrate resources. In many areas, the ocean habitats, cold-seep communities do not deep-sea coral Lophelia pertusa forms another depend upon sunlight as their primary source of almost-unexplored habitat. Branches of living energy. Instead, these communities derive their coral grow on mounds of dead coral branches energy from chemicals through a process called that can be several meters deep and hundreds chemosynthesis (in contrast to photosynthesis in of meters tall. Unlike corals that produce reefs in which sunlight is the basic energy source). MMS shallower waters, Lophelia does not have symbiot- scientists are particularly interested in finding ic algae and receives nutrition from plankton and deep-sea chemosynthetic communities in the Gulf particulate material captured by its polyps from of Mexico, because these are unique communi- the surrounding water. Lophelia mounds alter the ties that often include species that are new to sci- flow of currents and provide habitats for a variety ence and whose potential importance is presently of filter feeders. Scientists suspect that many other unknown. In addition, the presence of these com- organisms may also inhabit deep-sea coral reefs, munities often indicates the presence of hydrocar- including commercially important fishes and crus- bons at the surface of the seafloor. taceans. But they don’t know for sure, because most of the hard bottom and deep-sea coral habi- The 2006 Expedition to the Deep Slope was tats on the edge and slope of the continental shelf focused on discovering and studying the sea floor are still unexplored. communities found near seeping hydrocarbons on hard bottom in the deep Gulf of Mexico. The sites In this activity, students will research basic infor- visited by the Expedition were in areas where mation on Lophelia pertusa and interpret results energy companies will soon begin to drill for oil of a preliminary study of polyp behavior in this and gas. A key objective was to provide infor- species. mation on the ecology and biodiversity of these communities to regulatory agencies and energy LEARNING PROCEDURE companies. Expedition to the Deep Slope 2007 1. To prepare for this lesson, visit http://oceanexplorer. is focused on detailed sampling and mapping of noaa.gov/explorations/07mexico/welcome.html for informa- four key sites visited in 2006, as well as explor- tion about Expedition to the Deep Slope 2007. ing new sites identified from seismic survey data. You may want to visit http://www.bio.psu.edu/cold_seeps for a virtual tour of a cold-seep community, and While locating and exploring chemosynthetic http://oceanexplorer.noaa.gov/explorations/islands01/back- communities is a primary objective of the Deep ground/islands/sup10_lophelia.html for more background Slope expeditions, another objective is to explore on Lophelia reefs. and describe all other hard bottom biological communities in the central and western Gulf of 2. Introduce Expedition to the Deep Slope 2007, Mexico, regardless of whether or not they are and briefly discuss the importance of deep-sea associated with active hydrocarbon seepage or bottom communities and the fact that these chemosynthetic communities. Protecting these communities are largely unexplored. Be sure communities is an essential component of the students understand that cold-seep communities overall MMS mission. are one type of deep-sea community, but that there are others that are also important and require protection from potential damage by human activities. 2 Expedition to the Deep Slope 2007 – Grades 9-12 (Life Science) oceanexplorer.noaa.gov Focus: Biology and ecology of Lophelia corals 3. Tell students that their assignment is to prepare f. Why might L. pertusa polyps suddenly a written report on Lophelia pertusa that should retract? include: [Because they are disturbed by some exter- • A brief summary of the biology of this species nal factor; or because a rapid retraction (what kind of animal is it and what are its could produce a more vigorous water move- general characteristics) ment (possibly useful for exchanging water • Preferred habitat (where is it found, what are in the coelenteron cavity or for expelling the general physical conditions in this habitat) waste products of metabolism); or …] • Associations with other species • Significance to humans g. Why might L. pertusa periodically extend • Interactions with humans and contract? [To exchange water in the coelenteron cavity 4. Provide each student group with a copy of or expel waste products of metabolism; or “Preliminary Studies of Lophelia pertusa Polyp …] Behavior.” Each group should graph the data and answer the following questions h. Does sand appear to have an effect on L. a. Why did scientists want to avoid exposing pertusa polyps? If so, what is the effect? the corals to visible light? [Yes, it appears to reduce extension of the [To avoid exposing the corals to an unnatu- polyps.] ral physical factor (light) that might affect their behavior, since these corals normally 5. Lead a group discussion about Lophelia per- live in very deep waters where there is virtu- tusa and the results of preliminary experiments ally no light.] on the behavior of L. pertusa polyps. Student reports should address the questions listed b. How did the scientists control their experi- above, and should include most of the follow- ment for possible effects of infrared light? ing points: [They didn’t.] • L. pertusa is a scleractinian (stony) coral with a branched growth form; live corals are often c. In the second experiment, why did the scien- found growing on mounds of dead branches tists have one colony that was not exposed that form deep-water reefs. to sand? • About 20 of 703 known species of deep-sea [To provide a control for the experimental scleractinians build reef structures. treatment.] • L. pertusa is distributed throughout the Earth’s oceans except in polar regions, usually in d. Other researchers have suggested that L. per- depths ranging from 200 m to 1,000 m at tusa polyps are permanently expanded. Do temperatures between 6° C and 8° C; live L. data from this study support this idea? pertusa reefs have been reported from depths [No.] greater than 3,000 m. • Growth rates of L. pertusa have been esti- e. Do L. pertusa polyps extend and retract at mated at 4 – 5 mm per year, which is slower the same rate? than that of reef-building corals in shallow [No; the rate of extension is slower than the water. rate of retraction.] • Deep-sea corals often are long-lived and may be hundreds of years old. • The branching growth form of L. pertusa pro- 3 Expedition to the Deep Slope 2007 – Grades 9-12 (Life Science) Focus: Biology and ecology of Lophelia corals oceanexplorer.noaa.gov vides a variety of habitats for other species. extent and diversity of these reefs (like many other • Complex biological communities are asso- biological communities in the deep ocean) simply ciated with L. pertusa reefs on continental wasn’t known until recently, and the potential ben- shelves, slopes, and seamounts. efits of other species associated with these reefs • Biological diversity on L. pertusa reefs has are still unknown. The availability of deep-sea been reported to be about three times greater exploration technology has been critical to gain- than on surrounding soft bottom habitats. ing a better understanding of these systems and • About 800 species have been reported to the extent to which they are threatened.
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