One Tough Worm [Adapted from the 2002 Gulf of Mexico Expedition]

Expedition to the Deep Slope 2007

One Tough Worm [adapted from the 2002 Gulf of Mexico Expedition]

Focus group (download from or refer students to http:// Physiological adaptations to toxic and hypoxic asgsb.indstate.edu/bulletins/v13n2/vol13n2p13-24.pdf environments Audio/Visual Materials Grade Level None 7-8 (Life Science) Teaching Time Focus Question One 45-minute class period for first part of activ- How can aerobic organisms cope with environ- ity, plus one-half to one additional 45-minute class ments containing little oxygen and an abundance period for group reports and discussion of respiratory poisons? Seating Arrangement Learning Objectives Groups of four students Students will be able to explain the process of chemosynthesis. Maximum Number of Students 20 Students will be able to explain the relevance of chemosynthesis to biological communities in the Key Words vicinity of cold seeps. Cold seeps Methane hydrate ice Students will be able to describe three physiologi- Chemosynthesis cal adaptations that enhance an organism’s abil- Brine pool ity to extract oxygen from its environment. Vestimentifera Trophosome Students will be able to describe the problems Fick’s equation posed by hydrogen sulfide for aerobic organisms, Hemoglobin and explain three strategies for dealing with these Hydrogen sulfide problems. Mitochondria Aerobic Materials Anaerobic  Copies of “Comparative Functional Gill Characteristics of Polychaete Gills,” one copy for each student group Background Information  Copies of “Metazoans in Extreme Cold seeps are areas of the ocean floor where Environments,” one copy for each student gases (such as methane and hydrogen sulfide) Expedition to the Deep Slope 2007 – Grades 7-8 (Life Science) Focus: Physiological adaptations to toxic and hypoxic environments oceanexplorer.noaa.gov

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 Vestimentifera have been included in the phylum include species that are new to science and Annelida). Pogonophora means “beard bear- whose potential importance is presently unknown. ing,” and refers to the fact that many species in In addition, the presence of these communities this phylum have one or more tentacles at their often indicates the presence of hydrocarbons at anterior end. Tentacles of vestimentiferans are the surface of the seafloor. bright red because they contain hemoglobin

Expedition to the Deep Slope 2007 – Grades 7-8 (Life Science) oceanexplorer.noaa.gov Focus: Physiological adaptations to toxic and hypoxic environments

The 2006 Expedition to the Deep Slope was and avoiding the toxic effects of hydrogen sulfide. focused on discovering and studying the sea floor communities found near seeping hydrocarbons There are several strategies that organisms may on hard bottom in the deep Gulf of Mexico. use to improve their ability to obtain oxygen The sites visited by the Expedition were in areas from their surrounding environment. Three of the where energy companies will soon begin to drill most common strategies are anatomical adapta- for oil and gas. A key objective was to provide tions that increase an organism’s surface area in information on the ecology and biodiversity of contact with a source of oxygen, thin membranes these communities to regulatory agencies and between the interior of the organism and an energy companies. Dives by scientists aboard oxygen source, and internal circulatory systems the research submersible ALVIN revealed that that transport oxygen within the organism. These hydrocarbons seepage and chemosynthetic com- strategies are related by Fick’s equation which munities were present at all ten sites visited by the describes the passive diffusion of gas molecules Expedition. The most abundant chemosynthetic across a membrane: organisms seen were mussels and vestimentiferan tubeworms. Expedition to the Deep Slope 2007 F = A • P • c is focused on detailed sampling and mapping of D four key sites visited in 2006, as well as explor- where ing new sites identified from seismic survey data. F = gas flow A = membrane surface area This activity focuses on some of the physiological P = pressure difference on the two sides adaptations that allow cold seep organisms to of the membrane survive conditions that would be deadly to many c = a mathematical constant other species. Polychaete “ice worms” received D = distance over which diffusion takes a lot of attention when they were first discovered place (at the minimum, thickness of at Gulf of Mexico cold seeps in 1997, because the membrane) they were found living inside chunks of frozen methane. Another polychaete belonging to the So, gas flow across a membrane will be family Orbiniidae (previously unknown to sci- increased by increasing the membrane’s surface ence) is often found living among mussel beds area, reducing the membrane’s thickness, and/ that are one of the most conspicuous features of or increasing the pressure difference across the these cold-seep communities. These polychaetes membrane. “Pressure difference” is related to the are aerobic animals, which means they require difference in concentration of a gas on one side oxygen for their metabolism. Yet, these worms live of the membrane compared to the other side. If in areas where oxygen is in extremely short sup- there is no difference, then there will be no net ply, and often can’t be detected in the water at flow of gas (according to Fick’s equation, if P = all. To make matters worse, sediments around the 0 then F = 0). An organism can’t do much about mussel beds contain large quantities of hydrogen the concentration of gas in the external environ- sulfide, which is similar to cyanide in its toxicity. ment, but if it has a way to move gas away from Hydrogen sulfide interferes with cytochrome mole- the membrane as the gas diffuses in, a pressure cules that are essential to aerobic metabolism, as difference can be maintained. A circulatory sys- well as hemoglobin that is used by many organ- tem is a well-known adaptation for maintaining isms to transport oxygen within living tissues. So this kind of pressure difference. If the circulatory our cold-seep polychaete has two big problems: system includes molecules that can bind the gas getting oxygen to support aerobic metabolism, as it diffuses in (like hemoglobin binds oxygen)

Expedition to the Deep Slope 2007 – Grades 7-8 (Life Science) Focus: Physiological adaptations to toxic and hypoxic environments oceanexplorer.noaa.gov

this also helps maintain the pressure gradient. adaptation in aquatic animals for increasing respiratory surface area (alveoli serve a similar Three major strategies are common among organ- function in lungs of humans and other animals). isms that must deal with potentially toxic sulfides. Discuss the role of hemoglobin in obtaining and The first is to switch from aerobic metabolism to transporting oxygen. anaerobic metabolism that does not require oxygen. Many invertebrates are capable of doing 3. Distribute a copy of “Comparative Functional this for varying periods of time. Another strategy Characteristics of Polychaete Gills” to each is to bind the sulfide with another material that student group. Assign one or more species keeps it from interacting with sensitive molecules to each group, and have the group calculate involved with aerobic metabolism. Tubeworms gas flow across their species’ gills using Fick’s from hydrothermal vents are known to have spe- equation and assuming that c and P are the cialized forms of hemoglobin that bind with sul- same for each species, but that neither c nor fide and keep it away from metabolically critical P is equal to zero. The point here is to have areas. The third strategy is to convert the sulfide students recognize the factors that affect gas molecules to something else that is not toxic to transport in gills and similar biological struc- the organism. This strategy has been found in a tures, and how anatomical differences between variety of animals that have mitochondria that are deep-sea and shallow-water species may affect able to oxidize sulfide to thiosulfate (which is rela- the efficiency with which these species are able tively nontoxic). to extract oxygen from their environment.

Learning Procedure 4. Have each group discuss their results, and 1. To prepare for this lesson, visit http://oceanexplorer. what these results imply about the environment noaa.gov/explorations/07mexico/welcome.html for informa- occupied by each species. Students should tion about Expedition to the Deep Slope 2007. recognize that polychaetes from hydrothermal You may want to visit http://www.bio.psu.edu/cold_seeps vent and cold seep communities have gills with for a virtual tour of a cold-seep community, and larger surface area and thinner diffusion mem- http://www.bio.psu.edu/hotvents for a virtual tour of a branes, which means that gills of these species hydrothermal vent community. are much more efficient at extracting oxygen from their environment than the shallow-water 2. Lead a discussion of deep-sea chemosynthetic species. Students should also recognize that communities. Contrast chemosynthesis with pho- these data are very limited and do not provide tosynthesis. Point out that there are a variety of a solid basis for reliable conclusions; but this is chemical reactions that can provide energy for the nature of “preliminary studies” that lead to chemosynthesis. testable hypotheses, which in turn can be the focus of more rigorous experiments with larger Review the problem of oxygen scarcity that sample sizes, replicates, and controls. The challenges the survival of the Orbiniid poly- results of such experiments can lead to conclu- chaete. Discuss adaptations that enhance an sions that are much more reliable. organism’s ability to extract oxygen from its environment. Be sure students understand the The Bridge Connection terms in Fick’s equation, and how an increase www.vims.edu/bridge/vents.html or decrease in each parameter would affect gas flow across a respiratory membrane. The “Me” Connection Students should realize that gills are a common Have students write a short essay on what physi-

Expedition to the Deep Slope 2007 – Grades 7-8 (Life Science) oceanexplorer.noaa.gov Focus: Physiological adaptations to toxic and hypoxic environments

ological adaptations would be required to allow identify the three alternative strategies discussed them to live near a hydrothermal vent or cold- in the “Background” section for dealing with seep, including a description of a day spent in this problem. one of these extreme environments. Multimedia Learning Objects Connections to Other Subjects http://www.learningdemo.com/noaa/ Click on the links English/Language Arts, Earth Science to Lessons 3, 5, 6, 11, and 12 for interac- tive multimedia presentations and Learning Assessment Activities on Deep-Sea Corals, Chemosynthesis Have students prepare individual written state- and Hydrothermal Vent Life, Deep-Sea Benthos, ments of their conclusions prior to oral presenta- Energy from the Oceans, and Food, Water, and tions in Step #4. Medicine from the Sea.

Extensions Other Relevant Lessons from the Ocean Exploration 1. Visit http://oceanexplorer.noaa.gov/explorations/07mexico/ Program welcome.html to keep up to date with the latest Let’s Go to the Video Tape! (11 pages; Expedition to the Deep Slope 2007 discoveries. 327kb PDF) (from the Cayman Islands Twilight Zone 2007 Expedition) http://oceanexplorer.noaa.gov/ 2. Distribute copies of “Metazoans in Extreme explorations/07twilightzone/background/edu/media/videotape.pdf Environments” or refer students to http://asgsb. indstate.edu/bulletins/v13n2/vol13n2p13-24.pdf. Have each Focus: Characteristics of biological communities group prepare a written report on the problems on deep-water coral habitats (Life Science) posed by hydrogen sulfide for inhabitants of hydrothermal vent and cold-seep communities, In this activity, students will recognize and identify and what strategies are used by organisms in some of the fauna groups found in deep-sea coral these communities to cope with these problems. communities, infer possible reasons for observed This article deals with several other problems distribution of groups of animals in deep-sea of “extreme environments” besides sulfide. You coral communities, and discuss the meaning of may want to direct students to the sulfide sec- “biological diversity.” Students will compare and tion alone, or alternatively, have them address contrast the concepts of “variety” and “relative the other problems as well, perhaps assigning abundance” as they relate to biological diversity, one additional problem to each group. and given abundance and distribution data of species, will be able to calculate an appropriate Lead a discussion based on student groups’ numeric indicator that describes the biological reports. Students should realize that adaptations diversity of a community. that favor oxygen extraction can also increase an organism’s exposure to hydrogen sulfide. Treasures in Jeopardy (8 pages; 278kb PDF) The problem is even trickier for organisms that (from the Cayman Islands Twilight Zone 2007 have a symbiotic relationship with chemosyn- Expedition) http://oceanexplorer.noaa.gov/explorations/ thetic bacteria that use hydrogen sulfide as an 07twilightzone/background/edu/media/treasures.pdf energy source: These organisms must live close to a source of hydrogen sulfide to provide their Focus: Conservation of deep-sea coral communi- symbiotic bacteria with this necessary raw ties (Life Science) material, but must simultaneously avoid being poisoned by the same material. Students should In this activity, students will compare and contrast

Expedition to the Deep Slope 2007 – Grades 7-8 (Life Science) Focus: Physiological adaptations to toxic and hypoxic environments oceanexplorer.noaa.gov

deep-sea coral communities with their shallow- explorations/02hawaii/background/education/media/nwhi_map- water counterparts and explain at least three ben- ping.pdf efits associated with deep-sea coral communities. Students will also describe human activities that Focus: Bathymetric mapping of deep-sea habitats threaten deep-sea coral communities and describe (Earth Science - This activity can be easily modi- actions that should be taken to protect resources fied for Grades 5-6) of deep-sea coral communities. In this activity, students will be able to create a Come on Down! (6 pages, 464k) (from the two-dimensional topographic map given bathy- 2002 Galapagos Rift Expedition) http://oceanexplorer. metric survey data, will create a three-dimen- noaa.gov/explorations/02galapagos/background/education/media/ sional model of landforms from a two-dimensional gal_gr7_8_l1.pdf topographic map, and will be able to interpret two- and three-dimensional topographic data. Focus: Ocean Exploration Life is Weird (8 pages, 268k) (from the 2006 In this activity, students will research the develop- Expedition to the Deep Slope) http://oceanexplorer.noaa. ment and use of research vessels/vehicles used gov/explorations/06mexico/background/edu/GOM%2006%20Weird. for deep ocean exploration; students will cal- pdf culate the density of objects by determining the mass and volume; students will construct a device Focus: Biological organisms in cold-seep commu- that exhibits neutral buoyancy. nities (Life Science)

Living by the Code (5 pages, 400k) (from the In this activity, students will be able to describe 2003 Deep Sea Medicines Expedition) http://ocean- major features of cold-seep communities, and list explorer.noaa.gov/explorations/03bio/background/edu/media/ at least five organisms typical of these communi- Meds_LivingCode.pdf ties. Students will also be able to infer probable trophic relationships among organisms typical of Focus: Functions of cell organelles and the genet- cold-seep communities and the surrounding deep- ic code in chemical synthesis (Life Science) sea environment, and describe the process of chemosynthesis in general terms, and will be able to In this activity, students will be able to explain contrast chemosynthesis and photosynthesis. why new drugs are needed to treat cardiovascu- lar disease, cancer, inflammation, and infections; It’s a Gas! Or Is It? (12 pages, 276k) (from infer why sessile marine invertebrates appear to the 2006 Expedition to the Deep Slope) http:// be promising sources of new drugs; and explain oceanexplorer.noaa.gov/explorations/06mexico/background/edu/ the overall process through which cells manu- GOM%2006%20Gas.pdf facture chemicals. Students will also be able to explain why it may be important to synthesize Focus: Effects of temperature and pressure on new drugs, rather than relying on the natural pro- solubility and phase state (Physical Science/Earth duction of drugs. Science)

Mapping Deep-sea Habitats in the In this activity, students will be able to describe Northwestern Hawaiian Islands (7 pages, the effect of temperature and pressure on solubili- 80kb) (from the 2002 Northwestern Hawaiian ty of gases and solid materials; describe the effect Islands Expedition) http://oceanexplorer.noaa.gov/ of temperature and pressure on the phase state

Expedition to the Deep Slope 2007 – Grades 7-8 (Life Science) oceanexplorer.noaa.gov Focus: Physiological adaptations to toxic and hypoxic environments

of gases; and infer explanations for observed http://asgsb.indstate.edu/bulletins/v13n2/vol13n2p13-24.pdf chemical phenomena around deep-sea volcanoes – Article on adaptations to life in hydrother- that are consistent with principles of solubility and mal vent and cold-seep communities phase state. http://www.accessexcellence.org/BF/bf01/arp/bf01p1.html Other Links and Resources – Verbatim transcript of a slide show on The Web links below are provided for informa- coping with toxic sulfide environments tional purposes only. Links outside of Ocean Explorer have been checked at the time of this Hourdez, S., L.A. Frederick, A. Schernecke, and page’s publication, but the linking sites may C.R. Fisher. Functional respiratory anat- become outdated or non-operational over time. omy of a deep-sea orbiniid polychaete from the Brine Pool NR-1 in the Gulf of http://oceanexplorer.noaa.gov/explorations/07mexico/welcome.html – Mexico. Invertebrate Biology 120:29-40. Follow Expedition to the Deep Slope 2007 – Technical journal article upon which this daily as documentaries and discoveries are activity is based. posted each day for your classroom use. National Science Education Standards http://www.bio.psu.edu/People/Faculty/Fisher/fhome.htm – Web Content Standard A: Science As Inquiry site for the senior biologist on Expedition to • Abilities necessary to do scientific inquiry the Deep Slope 2007 • Understanding about scientific inquiry http://www.rps.psu.edu/deep/ – Notes from another expedi- Content Standard B: Physical Science tion exploring deep-sea communities • Properties and changes in matter http://www-ocean.tamu.edu/Quarterdeck/QD5.3/macdonald.html – Article on cold-seep communities Content Standard C: Life Science • Structure and function in living systems http://nai.arc.nasa.gov/news_stories/news_detail.cfm?ID=86 • Diversity and adaptations of organisms – “Cafe Methane,” another article on cold- seep communities Ocean Literacy Essential Principles and Fundamental Concepts Paull, C.K., B. Hecker, C. Commeau, R.P. Feeman- Essential Principle 1. Lynde, C. Nuemann, W.P. Corso, G. The Earth has one big ocean with many features. Golubic, J. Hook, E. Sikes, and J. Curray. Fundamental Concept h. Although the ocean is 1984. Biological communities at Florida large, it is finite and resources are limited. Escarpment resemble hydrothermal vent communities. Science 226:965-967 – Early Essential Principle 3. report on cold-seep communities. The ocean is a major influence on weather and climate. Fundamental Concept f. The ocean has had, and http://www.divediscover.whoi.edu/vents/index.html – ”Dive and will continue to have, a significant influence on Discover: Hydrothermal Vents;” another climate change by absorbing, storing, and mov- great hydrothermal vent site from Woods ing heat, carbon and water. Hole Oceanographic Institution

Expedition to the Deep Slope 2007 – Grades 7-8 (Life Science) Focus: Physiological adaptations to toxic and hypoxic environments oceanexplorer.noaa.gov

Essential Principle 5. Fundamental Concept d. New technologies, The ocean supports a great diversity of life and ecosystems. sensors and tools are expanding our ability to Fundamental Concept c. Some major groups are explore the ocean. Ocean scientists are relying found exclusively in the ocean. The diversity of more and more on satellites, drifters, buoys, sub- major groups of organisms is much greater in the sea observatories and unmanned submersibles. ocean than on land. Fundamental Concept f. Ocean exploration is Fundamental Concept d. Ocean biology provides truly interdisciplinary. It requires close collabora- many unique examples of life cycles, adaptations tion among biologists, chemists, climatologists, and important relationships among organisms computer programmers, engineers, geologists, (such as symbiosis, predator-prey dynamics and meteorologists, and physicists, and new ways of energy transfer) that do not occur on land. thinking. Fundamental Concept g. There are deep ocean ecosystems that are independent of energy Send Us Your Feedback from sunlight and photosynthetic organisms. We value your feedback on this lesson. Hydrothermal vents, submarine hot springs, and Please send your comments to: methane cold seeps rely only on chemical energy [email protected] and chemosynthetic organisms to support life. For More Information Essential Principle 6. Paula Keener-Chavis, Director, Education Programs The ocean and humans are inextricably interconnected. NOAA Ocean Exploration Program Fundamental Concept b. From the ocean we Hollings Marine Laboratory get foods, medicines, and mineral and energy 331 Fort Johnson Road, Charleston SC 29412 resources. In addition, it provides jobs, supports 843.762.8818 our nation’s economy, serves as a highway for 843.762.8737 (fax) transportation of goods and people, and plays a [email protected] role in national security. Fundamental Concept g. Everyone is responsible Acknowledgements for caring for the ocean. The ocean sustains life This lesson plan was produced by Mel Goodwin, on Earth and humans must live in ways that sus- PhD, The Harmony Project, Charleston, SC tain the ocean. Individual and collective actions for the National Oceanic and Atmospheric are needed to effectively manage ocean resourc- Administration. If reproducing this lesson, please es for all. cite NOAA as the source, and provide the follow- ing URL: http://oceanexplorer.noaa.gov Essential Principle 7. The ocean is largely unexplored. Fundamental Concept a. The ocean is the last and largest unexplored place on Earth—less than 5% of it has been explored. This is the great frontier for the next generation’s explorers and researchers, where they will find great opportuni- ties for inquiry and investigation. Fundamental Concept b. Understanding the ocean is more than a matter of curiosity. Exploration, inquiry and study are required to bet- ter understand ocean systems and processes.

Expedition to the Deep Slope 2007 – Grades 7-8 (Life Science) oceanexplorer.noaa.gov Focus: Physiological adaptations to toxic and hypoxic environments

Student Handout

Comparative Functional Characteristics of Polychaete Gills (modified from Hourdez, et al., 2001)

Species Habitat Gill Surface Area Minimum (cm2/g Diffusion Distance (µm) body wet weight) Branchipolynoe symmytilida vent 14.2 10 Branchipolynoe seepensis vent 10.3 9 Paralvinella grasslei vent 47 4 Alvinella pompejana vent 12 1-3 Arenicola marina shallow mud 4 8-14 Undescribed Orbiniidae seep 8 4