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Home , Atlantic Ocean, Hydrothermal vent

2006 Submarine

Where Did They Come From? (adapted from the 2005 Galapagos: Where Ridge Meets Expedition)

Focus Seating Arrangement of communities Classroom style or groups of 3-4 students

Grade Level Maximum Number of Students 9-12 ( Science) 30

Focus Question Key Words Why are different hydrothermal vent communities Hydrothermal vent inhabited by different species? Spreading center Biogeography Learning Objectives Biogeographic province Students will be able to define and describe bio- Mid- ridge geographic provinces of hydrothermal vent com- munities. Ring of Fire Mariana Arc Students will be able to identify and discuss processes that could contribute to isolation and Background Information species exchange between hydrothermal vent The Submarine Ring of Fire is an arc of active vol- communities. canoes that partially encircles the Basin and results from the motion of large pieces Students will be able to discuss characteristics of the ’s crust known as tectonic plates. that may contribute to the survival of species that These plates are portions of the Earth’s outer crust inhabit hydrothermal vent communities. (the lithosphere) about 5 km thick, as well as the upper 60 - 75 km of the underlying mantle. The Materials plates move on a hot flowing mantle layer called  Copies of “Guidance Questions for Research on the asthenosphere, which is several hundred the Biogeography of Hydrothermal Vents,” one kilometers thick. Heat within the asthenosphere copy for each student or student group creates convection currents (similar to the currents that can be seen if food coloring is added to a Audio/Visual Materials heated container of ) that cause the tectonic  None plates to move several centimeters per year rela- tive to each other. Teaching Time One or two 45-minute class periods, plus time for If tectonic plates are moving apart their junction student research is called a divergent plate boundary; if they slide  2006 Submarine Ring of Fire – Grades 9-12 (Life Science) Focus: Biogeography of hydrothermal vent communities oceanexplorer.noaa.gov

horizontally past each other they form a transform before. Since they were first discovered, -floor plate boundary; and if they collide more or less hot springs around spreading ridges have been head-on they form a convergent plate boundary. intensively studied. In contrast, the hydrothermal The Pacific Ocean Basin lies on top of the Pacific systems around convergent plate boundaries are Plate. To the east, new crust is formed by relatively unexplored. rising from deep within the Earth and erupt- ing at divergent plate boundaries between the Some of the key questions about hydrothermal Pacific Plate and the North American and South systems concerns biogeography: How do new American Plates. These eruptions form subma- vents become populated with that are rine mountain ranges called oceanic spreading uniquely adapted to the extreme conditions that ridges. While the process is volcanic, volcanoes are characteristic of these ? Since vents and earthquakes along oceanic spreading ridges can appear (and disappear) relatively quickly, are not as violent as they are at convergent plate what reproductive strategies might be used by boundaries. vent organisms to ensure that their offspring have a chance of finding a suitable ? Previous To the west, the Pacific Plate converges against expeditions to the Submarine Ring of Fire, and the Philippine Plate. The Pacific Plate is forced to other active hydrothermal vent sites such as beneath the Philippine Plate, creating the the Galapagos , have provided some clues to Marianas Trench (which includes the Challenger these questions. The 2006 Submarine Ring of Fire Deep, the deepest known area of the Earth’s Expedition is focussed on interdisciplinary investi- ocean). As the sinking plate moves deeper into gations of the hydrothermal and volcanic process- the mantle, fluids are released from the rock caus- es on the submarine volcanoes of the Mariana ing the overlying mantle to partially melt. The Arc, and will probably provide some additional new magma (molten rock) rises and may erupt clues; as well as some additional questions. This violently to form volcanoes, often forming arcs is the of exploration and scientific inquiry. of along the . The In this lesson, students will investigate some Mariana Islands are the result of this volcanic aspects of the biogeography of hydrothermal vent activity, which frequently causes earthquakes as systems. well. The movement of the Pacific Ocean tectonic plate has been likened to a huge conveyor belt Learning Procedure on which new crust is formed at the oceanic 1. To prepare for this lesson, review spreading ridges off the western coasts of North • Introductory essays for the 2006 Submarine and , and older crust is recycled to Ring of Fire Expedition at http://oceanexplorer.noaa. the lower mantle at the convergent plate boundar- gov/explorations/06fire/welcome.html; ies of the western Pacific. • NOAA Learning Object on Hydrothermal Vent Life at http://www.learningdemo.com/noaa/; and Underwater produces hot springs in the • Articles on biogeography of hydrothermal middle of cold, deep ocean . These springs vents by Cindy Lee Van Dover and Timothy (known as hydrothermal vents) were first discov- Shank (http://www.divediscover.whoi.edu/hottopics/biogeo. ered in 1977 when scientists in the submersible html and http://www.whoi.edu/cms/files/dfino/2005/4/ Alvin visited an oceanic spreading ridge near the v42n2-shank_2276.pdf, respectively). Galapagos Islands, and made one of the most exciting discoveries in 20th century biology. Here You may also want to visit the Dive and they found warm springs surrounded by large Discover presentation on the 25th anniver- numbers of that had never been seen sary of the discovery of hydrothermal vents

 2006 Submarine Ring of Fire – Grades 9-12 (Life Science) oceanexplorer.noaa.gov Focus: Biogeography of hydrothermal vent communities

(http://www.divediscover.whoi.edu/ventcd/vent_discovery), islands and formed from hotspot and obtain the CD-ROM or download selected lava as a plate moves over a hotspot location. images to enhance group discussions in Step 4. • Hydrothermal vent biogeographic provinces 2. Briefly review the concepts of plate tectonics, include the Northeast Pacific (Gorda, Juan de being sure that students understand the process- Fuca, and systems); Eastern es that take place at convergent and divergent Pacific ( and Galapagos boundaries, and why these boundaries are spreading center systems); Western Pacific often the site of volcanic activity. Introduce the (Mariana, Lau, , and Manus systems); Ring of Fire expeditions, and tell students that a Deep Atlantic (or Mid-Atlantic) (Trans-Atlantic primary focus of the 2006 Submarine Ring of Geotraverse (TAG), Snake Pit, and Broken Fire Expedition is interdisciplinary investigations Spur systems); Shallow Atlantic (or Azorean) of hydrothermal and volcanic processes on (Menez Gwen and Lucky Strike systems); and the portion of the Ring of Fire that includes the Central Indian (Kairei and Edmond systems). Mariana Arc. • Species that characterize the biogeographic 3. Tell students that their assignment is to research provinces of hydrothermal vent systems are: some basic questions and theories about the – tubeworms, , and (eastern biogeography of hydrothermal vent systems, Pacific and northeast Pacific; different and prepare a report that includes answers species of each group in each province); to the ”Guidance Questions for Research on – shrimp and (Deep Atlantic and the Biogeography of Hydrothermal Vents.” Shallow Atlantic; different species of each Information needed to answer questions on the group in each province); and worksheet can be found on the Web sites refer- – barnacles, mussels, and (western enced in Step 1, as well as many other sourc- Pacific; different species than those found es. You may want to provide these references in the eastern Pacific or Atlantic). to your students, or allow them to discover them The province is dominated by (and others) on their own. shrimp similar to those found in the Atlantic, as well as snails and barnacles similar to 4. a discussion of students’ reports. The fol- those in the western Pacific province. lowing points should be included: • Processes that can contribute to migrations • A spreading center (mid-ocean ridge) is between hydrothermal vent communities formed where tectonic plates move apart include: (divergent plate boundaries). This movement – whalefalls – of car- causes a rift to form that allows magma casses that fall to the seafloor creates (molten rock) to escape from deep within conditions that are somewhat similar to the Earth and become new crust material. those found at hydrothermal vent sites, Hotspots are thought to be formed by natu- so these carcasses may provide “step- ral pipelines to reservoirs of magma in the ping stones” for the migration of species upper portion of the Earth’s mantle, and are between vent sites; believed be relatively stationary compared – woodfalls – decomposing wrecks of wood- to tectonic plates. The combination of com- en may create conditions similar to paratively stationary hotspots and plates that those described for whale carcasses; are in constant motion produces “chains” of – larval dispersal – motile larvae are prob-

 2006 Submarine Ring of Fire – Grades 9-12 (Life Science) Focus: Biogeography of hydrothermal vent communities oceanexplorer.noaa.gov

ably one of the primary means of species basin was formed; dispersal; – The connecting the Pacific – deep-sea currents – that can carry adult and Atlantic did not exist until organisms or larvae are probably are 21 million years ago; and major factor in the dispersal of many spe- – The Romanche and Chain Fracture Zones cies; and near the and a strong deep-sea – “stepping stones” – in addition to whale- current in the same area could act as falls and woodfalls, other “stepping barriers to the migration of animals from stones” include seamounts and underwa- the South Atlantic to North Atlantic. ter volcanoes. • The presence of clams at the Logatchev vent • Factors that could contribute to geographic site may be the result of the fact that the isth- isolation include: mus of Panama (which is now a barrier to – topographic features, such as deep rift val- species exchange between the Atlantic and leys like those found along the Atlantic Pacific Oceans) was under water until 5 mil- mid-ocean ridge, or massive transform lion years ago, so larvae of vent clams could faults that are roughly perpendicular to have migrated from Pacific hydrothermal sites mid-ocean ridges; to Atlantic sites prior to this time. – tectonic movements that close pathways between (see below); and • The key to a species’ success in a precarious – deep-sea currents (see below). environment is that the benefits of living in such an environment must outweigh the risks. • A proposed explanation for the similarities Being able to thrive under the thermal and and differences among the vent fauna of the chemical conditions typical of hydrothermal and East Pacific Rise is vents is an obvious requirement. In addition, that, at one time, the East Pacific Rise was rapid growth to maturity is important so that probably continuous along the western Pacific the species has a chance to reproduce before through the Juan de Fuca Ridge. When the the next erupts. If a volcano does North American tectonic plate overrode the not erupt, there is an increased chance that Pacific plate, the East Pacific Rise was sub- other species may successfully compete with ducted beneath the tubeworms for nutritional or space resources. where we now recognize the San Andreas There is some suggestion that this occurred fault. The result was to isolate the Juan de at the site of the famous Rose Garden vent; Fuca Ridge from the East Pacific Rise. tubeworms were abundant when the vent was discovered in 1977, but were greatly • Some factors that may have tended to iso- reduced compared to mussels when the site late hydrothermal vent habitats in the North was re-visited in 1985. Atlantic from sites in the Pacific include: – The North basin formed The Bridge Connection about 180 million years ago, but the www.vims.edu/bridge – Select “Ocean Science Topics,” South American and African then select “,” then “” did not separate until 110 million years ago, so the North Atlantic and South The “Me” Connection Atlantic Oceans were separated for 70 Many human communities on Earth have become million years after the North Atlantic much less geographically isolated in the last two

 2006 Submarine Ring of Fire – Grades 9-12 (Life Science) oceanexplorer.noaa.gov Focus: Biogeography of hydrothermal vent communities

hundred years. Have students write a short essay Students will be able to define and describe in which they explore the advantages and disad- systems; explain the vantages of reduced geographic isolation to their overall sequence of chemical reactions that own and themselves. occur in hydrothermal circulation systems; compare and contrast “black smokers” and Connections to Other Subjects “white smokers;” and make inferences about English/Language arts; Physical Science; the relative significance of hydrothermal cir- ; culation systems to ocean chemical balance from data on chemical enrichment that occurs Assessment in these systems. Reports and discussions in Steps 3 and 4 provide opportunities for assessment. What’s the Difference? http://www.oceanexplorer. noaa.gov/explorations/05fire/background/edu/media/rof05_ Extensions difference.pdf (7 pages, 720k) (from the New 1. Visit http://oceanexplorer.noaa.gov/explorations/06fire/ American Submarine Ring of Fire welcome.html for daily logs and updates about 2005 Expedition) discoveries being made by the 2006 Submarine Ring of Fire Expedition. Focus: Volcanic processes at convergent and divergent tectonic plate boundaries (Earth 2. Visit these sites for many more activities and Science) links related to plate tectonics, earthquakes and seismology: Students will be able to compare and contrast http://www.ldeo.columbia.edu/~mwest/WS4instructors/ volcanoes at convergent and divergent plate primer.html boundaries; identify three geologic features http://lasker.princeton.edu/ScienceProjects/curr.htm that are associated with most volcanoes on http://mae.ce.uiuc.edu/Education/Teachers/high.htm Earth; and explain why some volcanoes erupt explosively while others do not. Resources Multimedia Learning Objects Where There’s Smoke, There’s . . . http:// http://www.learningdemo.com/noaa/ – Click on the links to www.oceanexplorer.noaa.gov/explorations/05fire/background/ Lessons 1, 2, 4, and 5 for interactive multimedia edu/media/rof05_smoke.pdf (6 pages, 680k) (from presentations and Learning Activities on Plate the American Submarine Ring Tectonics, Mid-Ocean Ridges, Zones, of Fire 2005 Expedition) and and Hydrothermal Vent Life Focus: Hydrothermal vent chemistry at sub- Other Relevant Lesson Plans from the duction volcanoes (Chemistry) Program The Big Balancing Act http://www.oceanexplorer.noaa. Students will be able to use fundamental gov/explorations/05fire/background/edu/media/rof05_bal- relationships between melting points, boiling ancing.pdf (9 pages, 1.3Mb) (from the New points, solubility, temperature, and pressure to Zealand American Submarine Ring of Fire develop plausible explanations for observed 2005 Expedition) chemical phenomena in the vicinity of sub- duction volcanoes. Focus: Hydrothermal vent chemistry at sub- duction volcanoes (Chemistry/Earth Science)

 2006 Submarine Ring of Fire – Grades 9-12 (Life Science) Focus: Biogeography of hydrothermal vent communities oceanexplorer.noaa.gov

It Looks Like Champagne http://www.oceanex- Chemosynthesis for the Classroom http:// plorer.noaa.gov/explorations/05fire/background/edu/media/ www.oceanexplorer.noaa.gov/explorations/02mexico/back- rof05_champagne.pdf (7 pages, 736k) (from the ground/edu/media/gom_chemo_gr912.pdf (6 pages, New Zealand American Submarine Ring of 464k) (from the 2002 Gulf of Fire 2005 Expedition) Expedition)

Focus: Deep ocean carbon dioxide and glob- Focus: Chemosynthetic and suc- al change (Chemistry/Earth Science) cession in chemosynthetic communities (Chemistry/Biology) Students will be able to interpret phase dia- grams, and explain the meaning of “critical Students will observe the development of che- point” and “triple point;” define “supercritical mosynthetic bacterial communities and will fluid,” and will be able to describe two practical recognize that organisms modify their envi- uses of supercritical carbon dioxide; and discuss ronment in ways that create opportunities for the concept of carbon dioxide sequestration. other organisms to thrive. Students will also be able to explain the process of chemosyn- The Galapagos Spreading Center http://www. thesis and the relevance of chemosynthesis to oceanexplorer.noaa.gov/explorations/02galapagos/back- biological communities in the vicinity of cold ground/education/media/gal_gr9_12_l2.pdf (8 pages, seeps. 480k) (from the 2002 Galapagos Rift Expedition) Other Links and Resources http://www.oceanexplorer.noaa.gov/explorations/04fire/background/ Focus: Mid-Ocean Ridges (Earth Science) marianaarc/marianaarc.html – Virtual fly-throughs and panoramas of eight sites in the Students will be able to describe the pro- Mariana Arc cesses involved in creating new seafloor at a mid-ocean ridge; students will investigate http://www.oceanexplorer.noaa.gov/explorations/02fire/logs/magic- the Galapagos Spreading Center system; mountain/welcome.html – Magic Mountain Virtual students will understand the different types of Web site, featuring animations and videos plate motion associated with ridge segments of the Magic Mountain hydrothermal field and transform faults. http://oceanexplorer.noaa.gov/explorations/03fire/logs/subduction. Thar She Blows! http://www.oceanexplorer.noaa.gov/ html and http://oceanexplorer.noaa.gov/explorations/ explorations/02galapagos/background/education/media/gal_ 03fire/logs/ridge.html – Animations of the 3- gr9_12_l3.pdf (5 pages, 456k) (from the 2002 dimensional structure of a mid-ocean ridge Galapagos Rift Expedition) and subduction zone

Focus: Hydrothermal vents http://pubs.usgs.gov/publications/text/dynamic.html#anchor19309449 – On-line version of “This Dynamic Students will demonstrate an understanding of Earth,” a thorough publication of the U.S. how the processes that result in the formation Geological Survey on plate tectonics writ- of hydrothermal vents create new ocean floor; ten for a non-technical audience students will demonstrate an understanding of how the transfer of energy effects solids and http://pubs.usgs.gov/pdf/planet.html – “This Dynamic . Planet,” map and explanatory text showing

 2006 Submarine Ring of Fire – Grades 9-12 (Life Science) oceanexplorer.noaa.gov Focus: Biogeography of hydrothermal vent communities

Earth’s physiographic features, plate move- http://oceanexplorer.noaa.gov/explorations/05galapagos/welcome. ments, and locations of volcanoes, earth- html – Web page for the 2005 Galapagos quakes, and impact craters Spreading Center Expedition http://www.pmel.noaa.gov/vents/nemo/education.html – Web http://www.divediscover.whoi.edu/ventcd/vent_discovery – Dive site for the New Millennium Observatory and Discover presentation on the 25th anni- Project, a long-term study of the interactions versary of the discovery of hydrothermal vents between , chemistry, and biology on Axial , an active volcano on http://seawifs.gsfc.nasa.gov/OCEAN_PLANET/HTML/ps_vents.html the Juan de Fuca Ridge that is part of the – Article, “Creatures of the Thermal Vents” mid-ocean ridge system by Dawn Stover http://vulcan.wr.usgs.gov/ – USGS Cascades Volcano http://www.oceansonline.com/hydrothe.htm – “Black Smokers Observatory, with extensive educational and Giant Worms,” article on hydrothermal and technical resources vent organisms http://volcano.und.edu/ – Volcano Web site at the Corliss, J. B., J. Dymond, L.I. Gordon, J.M. University of North Dakota Edmond, R.P. von Herzen, R.D. Ballard, K. Green, D. Williams, A. Bainbridge, K. http://nationalzoo.si.edu/publications/zoogoer/1996/3/lifewithout- Crane, and T. H. Andel, 1979. Submarine light.cfm – “Life without Light: Discoveries thermal springs on the Galapagos Rift. from the Abyss,” by Robin Meadows; Science 203:1073-1083. – Scientific jour- Smithsonian National Zoological Park, nal article describing the first submersible Zoogoer Magazine, May/June 1996 visit to a hydrothermal vent community http://www.ngdc.noaa.gov/mgg/image/2minrelief.html – Index Shank, T. M. 2004. The evolutionary puzzle of page for NOAA’s National Geophysical seafloor life. 42(2):1-8; available Data Center combined global elevation online at http://www.whoi.edu/cms/files/dfino/2005/4/ and images (http://www.ngdc.noaa. v42n2-shank_2276.pdf. gov/mgg/image/2minsurface/45N135E.html includes the Mariana Arc) Tunnicliffe, V., 1992. Hydrothermal-vent communi- ties of the deep sea. American Scientist http://www.guam.net/pub/sshs/depart/science/mancuso/marianas/ 80:336-349. intromar.htm – Web site with background infor- mation on 15 of the Mariana Islands. Van Dover, C. L. Hot Topics: Biogeography of deep- sea hydrothermal vent faunas; available http://volcano.und.nodak.edu/vwdocs/volc_models/models.html – U online at http://www.divediscover.whoi.edu/hottopics/ of N. Dakota volcano Web site, directions biogeo.html for making various volcano models National Science Education Standards http://volcano.und.nodak.edu/vw.html – Volcano World Web Content Standard A: Science as Inquiry site • Abilities necessary to do scientific inquiry • Understandings about scientific inquiry http://www.extremescience.com/DeepestOcean.htm – Extreme Science Web page on the

 2006 Submarine Ring of Fire – Grades 9-12 (Life Science) Focus: Biogeography of hydrothermal vent communities oceanexplorer.noaa.gov

Content Standard C: Life Science among organisms (such as , preda- • Biological evolution tor-prey dynamics and energy transfer) that • Interdependence of organisms do not occur on land. • Behavior of organisms • Fundamental Concept e. The ocean is three- dimensional, offering vast living space and Content Standard D: Earth and Space Science diverse habitats from the surface through the • Energy in the Earth system to the seafloor. Most of the liv- • Geochemical cycles ing space on Earth is in the ocean. • Origin and evolution of the earth system • Fundamental Concept f. Ocean habitats are defined by environmental factors. Due to Content Standard E: Science and Technology interactions of abiotic factors such as salin- • Abilities of technological design ity, temperature, oxygen, pH, light, nutrients, pressure, substrate and circulation, ocean life Content Standard F: Science in Personal and Social is not evenly distributed temporally or spa- Perspectives tially, i.e., it is “patchy.” Some regions of the • Natural resources ocean support more diverse and abundant • Natural and human-induced hazards life than anywhere on Earth, while much of the ocean is considered a desert. Ocean Literacy Essential Principles and • Fundamental Concept g. There are deep Fundamental Concepts ocean that are independent of Essential Principle 2. energy from sunlight and photosynthetic The ocean and life in the ocean shape the features of the Earth. organisms. Hydrothermal vents, submarine • Fundamental Concept e. Tectonic activity, sea hot springs, and cold seeps rely level changes, and force of waves influence only on chemical energy and chemosynthetic the physical structure and of the organisms to support life. coast. Essential Principle 7. Essential Priniciple 5. The ocean is largely unexplored. The ocean supports a great diversity of life and ecosystems. • Fundamental Concept a. The ocean is the last • Fundamental Concept a. Ocean life ranges in and largest unexplored place on Earth—less size from the smallest virus to the largest ani- than 5% of it has been explored. This is the mal that has lived on Earth, the . great frontier for the next generation’s explor- • Fundamental Concept b. Most life in the ers and researchers, where they will find great ocean exists as microbes. Microbes are the opportunities for inquiry and investigation. most important primary producers in the • Fundamental Concept b. Understanding the ocean. Not only are they the most abundant ocean is more than a matter of curiosity. life form in the ocean, they have extremely Exploration, inquiry and study are required fast growth rates and life cycles. to better understand ocean systems and pro- • Fundamental Concept c. Some major groups cesses. are found exclusively in the ocean. The diver- • Fundamental Concept d. New technologies, sity of major groups of organisms is much sensors and tools are expanding our ability greater in the ocean than on land. to explore the ocean. Ocean scientists are • Fundamental Concept d. Ocean biology pro- relying more and more on satellites, drifters, vides many unique examples of life cycles, buoys, subsea observatories and unmanned adaptations and important relationships submersibles.

 2006 Submarine Ring of Fire – Grades 9-12 (Life Science) oceanexplorer.noaa.gov Focus: Biogeography of hydrothermal vent communities

• Fundamental Concept f. Ocean exploration is truly interdisciplinary. It requires close col- laboration among biologists, chemists, clima- tologists, computer programmers, engineers, geologists, meteorologists, and physicists, and new ways of thinking.

For More Information Paula Keener-Chavis, Director, Education Programs NOAA Office of Ocean Exploration Hollings Marine Laboratory 331 Fort Johnson Road, Charleston SC 29412 843.762.8818 843.762.8737 (fax) [email protected]

Acknowledgements This lesson plan was produced by Mel Goodwin, PhD, The Harmony Project, Charleston, SC for the National Oceanic and Atmospheric Administration. If reproducing this lesson, please cite NOAA as the source, and provide the follow- ing URL: http://oceanexplorer.noaa.gov

 2006 Submarine Ring of Fire – Grades 9-12 (Life Science) oceanexplorer.noaa.gov Focus: Biogeography of hydrothermal vent communities

Student Handout

Guidance Questions for Research on the Biogeography of Hydrothermal Vents

1. Compare and contrast: spreading center (mid-ocean ridge) and hotspot

2. What are the six biogeographic provinces of hydrothermal vent communities?

3. What species characterize these provinces?

4. When the same species are found in different hydrothermal vent communities, this suggests that these species are able to move between these communities. But some of these sites are tens to hundreds of miles apart. What are some processes that could contribute to migrations between these communities?

5. The existence of different biogeographic provinces suggests that these geographic areas have been isolated from each other in some way (if they were not isolated, fauna would be expected to mix across all of the sites so the same animals would be found everywhere). What are some factors that could contribute to this isola- tion?

6. The hydrothermal vent fauna of the Juan de Fuca Ridge (Northeast Pacific prov- ince) has many similarities with the fauna of the East Pacific Rise (Eastern Pacific province), yet is different enough to be considered a separate biogeographic prov- ince. What tectonic events provide a possible explanation for these observations?

7. What are some factors that may have tended to isolate hydrothermal vent habitats in the North Atlantic from sites in the Pacific?

8. What barrier may help explain the presence of clams at the Logatchev vent site?

9. Animals such as the vent tubeworm that live near tectonically active sites are, in a sense, living on borrowed time since there is a strong possibility of volcanic erup- tions that could bury living organisms under a blanket of hot lava. What character- istics might help such species avoid extinction? What may happen to such species if a volcano does not erupt?