Hydrothermal Vents Environments Chemosynthesis and symbioses Food Webs Evolution Biogeography Dispersal and Populations History of Discovery Hot vents first discovered in May 1975 from temperature Anomalies of only 0 1oC Lonsdale detected by Deep Tow Camera revealed piles of dead clams on hard substrate Unusual for deep sea large size and high density Geologists visited Galapagos vents first with ALVIN 1976 Biologists visited Galapagos 1979 oceanexplorer noaa gov plan plan html 1 Vents are partly a mid ocean ridge phenomenon Nicolas 1995 Spreading rate affects community development Mueller et al 1997 Crusts have differing ages in the different oceans Macdonald 1982 Fast Spreading 80 mm y Slow spreading 40 mm y 2 Oberlande r VENT COMMUNITIES Most trophic levels have energy derived from nonphotosynthetic pathways Food chains are based on oxidation of reduced compounds sulfide and methane Oberlande r 3 Importance 1 Brought biological oceanography to the attention of millions of non scientists 2 Changed thinking about life in deep sea evolution of life forms in general These communities represent the antithesis of former deep sea dogma Animals at active vents are less food limited exhibit rapid growth high metabolism large body size but low diversity WHAT ARE HYDROTHERMAL VENTS or very hot 389oC as at other East Pacific Rise sites Von Damm 1995 Water may be merely warm as at Galapagos 20oC Von Damm 1995 Places where seawater circulates inside the earth s crust and is ejected as thermal springs warmer than ambient water 4 Fluids are rich in metals and sulfides that precipitate when contacting ambient seawater forming chimneys Source of smoker terms e g black smoker white smoker Known vent sites Baker German 2004 5 Vent locations Biogeographic zones from Van Dover et al Science 2002 Major sites explored are along seafloor spreading centers plate margins where new crust is being formed East Pacific Rise separates the Pacific and Rivera Plates off Mexico S America near the Galapagos Central America Mexico and into Gulf of California Canada Washington and Oregon Explorer Ridge and Juan de Fuca region Mid Atlantic Ridge not found until 1986 though sought in 70s Marianas Trench W Pacific Bac Arc basins Subduction zones off Japan and Oregon 6 Newer Discoveries Southern MAR Arctic First vents discovered March 05 CD169 PI C German SOC Indian Ridges Antarctic Fossil Record Microbial communities 3 235 Ma Macrofaunal vent communities 430 Ma Seep similar Whale Fall 30 Ma Fossiized tube worms gastropods 7 Fossil Vents o Major Vent Taxa E Pacific vestimentiferan tube worms siboglinid polychaetes Largest is Riftia pachyptila bivalves Calyptogena spp C magnifica Vesicomya mussels Bathymodiolus spp alvinellid polychaetes live in some of the hottest water e g Alvinella pompeijana Gastropods limpets Lepetodrilus snails Depressigyra brachyuran and galatheid crabs vent fish 8 Vestimentiferans Tube Worms e g Riftia pachyptila Near hottest active vents Up to 3 m length rapid growth Vestimentifera Polychaeta Siboglinidae No mouth gut or anus in adults Plume accesses sulfide and oxygen which fuel sulfide oxidizing bacteria in the trophosome 1981 Taxonomic Scheme Jones Phylum Pogonophora Subphylum Obturata Class Afrenulata Order Vestimentifera Family Lamellibrachiidae Genus Riftia Species pachyptila Now Siboglinidae within Polychaeta BUT Kojima et al 1993 9 Habitat Requirement Riftia zone of turbulent mixing of vent fluids and ambient seawater Johnson et al 1988 Hessler Kaharl 1995 opisthosome plume vestimentum trophosome bacteria 10 Ridgea Juan de Fuca Ridge Growth rate 3 2 mm y Mortality Rate 4 per year Settlement Gregarious Root ball permeable to sulfide Fluid flow tolerance broad Urcayo et al 2003 Tube worms support associated taxa limpets snails scale worms barnacles crabs These filter and graze bacteria scavenge Scale worm limpet 11 Gastropoda Depressigyra Polynoidae Bivalves Vesicomya Calyptogena Just beyond hot water in cracks and fissures live clams and mussels Common clam is the vesicomyid Calyptogena magnifica Up to 20 cm or more Found at 21oN and Galapagos Genus is characteristic of vents and seeps all over the world Siphon must be in ambient water and foot takes up H2S in crevices Also requires crevice for support of valves 12 Oasis Expedition Arp et al 1984 modified by Scott Fisher 1995 Parallel evolution of clams symbionts 13 Mussels Bathymodiolus thermophilius Mytilid mussel related to shallow water taxa like Mytilus on pier pilings at Galapagos but not 21oN Blake Ridge MAR Wide habitat range Use methane sulfide as an energy source methanotrophic thiotrophic symbionts Can also use particulate food as well reproductive periodicity May survive periods of reduced vent activity Dual symbiosis in mussels Bathymodiolus heckerae M Methanotrophs M Thiotrophs M Relative importance of symbiont type varies with methane and sulfide concentrations in source waters nucleus Salerno Van Dover 14 Alvinellidae Alvinella pompeiana At white smokers construct white tubes Many related species found at vents around the world Have filamentous sulfur bacteria growing on their back Live in the warmest water greater than 300oC Grazers Paralvinella Juan de Fuca Ridge Photos by Paul Yancey 15 Mobile predators scavengers Munidopsis subsquamosa Bythograea thermydron galatheid brachyuran crab crab Vent fish Diplacanthopoma sp Other Taxa Serpulid polychaetes Cnidarians Enteropneusts Alvinocarid Shrimp 16 Vent communities differ between oceans Mid Atlantic Ridge Rimicaris exoculata 17 Bacterial Pad Bacteriophore Setae Scaphognathite of Maxilla Exopodite of Maxilliped I Episymbiotic sulfur bacteria O Neill et al 1995 cross section through shrimp cephalothorax photoreceptor cells May see Cherenkov radiation with specialized pigments on back 18 Guaymas Basin Sediments are saturated with hydrocarbons which form at high temperature from pelagic sediments One of the only things living in them are Ophyrotrocha spp dorvilleid polychaete Also present are large mats of yellow bacteria Beggiatoa Cells are up to 110 microns Marianas Back Arc Basin Dominated by gastropods that possess symbiotic chemoautotrophic bacteria Different fauna may be due to isolation 19 Van Dover et al 2001 Van Dover Van Dover Goffredi et al 2005 Indian Ocean Vents Van Dover et al 2001 Scaly foot gastropod 20 Yeti Crab New Family Kiwaidae 1500 km south of Easter Island Arctic Ridge Crests Knipovich Gakkel Ultra slow spreading center 21 Kermadec Arc Vents volcanic