Life in the Mud• Benthic productivity versus pelagicproductivityThe Benthos• By definition: organisms (animals andplants) that live on, in or attached tothe sea floor• Includes 98% of all marine species• Coral Reefs alone contain 25% of allmarine species!• Community composition determined bybenthic composition• Dunn et al., Nature 452:745-749Most phyla are found inmarine sediments--andlife may have originatedat a vent seepBenthic vs. Pelagic• Benthic organisms are not adapted towide ranges in pressure• There are very few transparentorganisms• Generally stay to a smaller spatial area(they don’t move around as much)• We classify them in relation to the typeof shoreline or bottom structureDeep-Sea GigantismDifferences between land and ocean:• Ocean currents move ocean animalsaround!• Small animals in the ocean can bepushed around by currents, and may notbe able to choose where they go.• Adult fish and mammals can swimstrongly, and adult invertebrates cling tothe bottom, but babies are at the mercy ofthe currentsStandard ecological theory (land):Animals are found in comfortable environmentsMarine ecological theory:Animals may be found where the currents put them.Depends on animal’s lifestyle. Whether they surviveor not is largely dependent on the availability offood or suitable habitat (subtrate) in thatenvironment.Distance from Santa Cruz:San Francisco: ~100kmLos Angeles: ~ 500 kmSalt Lake City: ~1000 kmBenthic Substrates• Rocky, sandy, or muddy intertidal• Muddy deposits or hydrothermaldeposits in the deep sea• Biomass is closely related to surface-water primary productionBenthic Diversity, Biomass• Benthic diversity is largely controlled by– Temperature (more in warmer waters)– Currents (this affects the benthic structure)– Wave Energy (infauna vs. epifauna)• Benthic Biomass is largely controlled by– Water column primary productivity• High Biomass often equals Low DiversityPrimary ProductionBenthic Biomasshttp://www.noc.soton.ac.uk/chess/education/edu_whale.phpWhale Falls—Deep-Sea Oases of ProductivityAt any given time, alarge food source(such as a whale fall)increases biomass oforganisms (feeding onthe carcass) butdecreases speciesdiversity (because ofspecialization)….However, the whalecan be thought of as asuccessionalcommunityMany marine species have ‘bipartite’ life histories1. Planktonic dispersive early stage2. benthic or site attached adult stageBENTHIC ADULTS REPRODUCTIONSETTLEMENTPLANKTONICLARVAE *Larva: an independent, often free-living, developmentalstage that undergoes changes in form and size to matureinto the adult; especially common in insects and aquaticorganisms. (From a Latin word meaning "ghost" or"mask.")More facts of nature: you don’t see the bipartite lifestyle often on landMarine organisms:complex life cyclesSeaurchinStarfishSea cucumbercrabsBryozoaPolychaeteGastropodPhoronidbarnaclenemerteanBipartite Lifestyles• A major component of benthic ecology dealswith recruitment• The larvae are often very different from theadult life stage• While planktonic, many larvae do notconsume food (they rely on internal reserves)• Some larvae utilize the DOM, acting as(essentially) very large bacteriaRetentionDemographically closedPelagic fisheries perspectiveHjort (1914)Stock-recruitment relationshipsRetentionDemographically closedLarval poolDispersalDemographically openBenthic ecology perspectiveThorson (1950)For organisms with multi-phase lifehistories, understanding the biotic andphysical mechanisms that regulateabundance/distribution of adults requiresintegrating the dynamics and distributionsof several aspects of the life cycle.Larval poolMixtureof larvalinputsTagging StudiesRetentionDemographically closedLarval poolDispersalDemographically openSwearer et al. 1999Jones et al. 1999 (Nature)Genetic pop. structure:Barber et al. 2000 (Nature)Largerreserves mayeliminatefisheriesbenefitsReserves and SpeciesPersistenceFrom Botsford, Hastings, and Gaines. 2001. Ecology Letters• Reserves can meetconservation goalsin two ways:– Large IndividualSize• > mean dispersaldistance• 2 - 3x meandispersal distancewith advection– Large TotalNetwork AreaPacific OceanLos AngelesModel DomainDong & McWilliams CSR (2007)Red dots: locations after 30 daysExample 30 Day TrajectoriesSurface following…[ km ]-2Dispersal from San Nicolasmillions of water parcel releasesDispersal from Other SitesAdvection time = 30 days[ km ]-2Advection time = 30 daysSeasonal VariabilityAdvection time = 30 daysInterannual VariabilityDeep-Sea Communitieshttp://www.tos.org/oceanography/issues/issue_archive/issue_pdfs/20_1/20.1_ramirez_et_al.pdfAbundance and diversity The vent fauna comprises a list of mainly new and undescribed species  1991: 223 of the 236 species listed were new to science  1998: 443 species were listed  Preponderence of three phyla: molluscs, arthropods and annelids The list of species is still growing  deep sea: 85 spp. on 61 manganese nodules at 2 sites  vents: 236 spp. from ~30 dives  intertidal boulder field: 214 invertebrate spp. in 9 0.01 m2 samples  temperate corals: 309 spp. on 8 coral heads most species are endemic to vents some deep-sea taxa are absent from vents most species are sessile with a few highly mobile ones ~75% of species only occur at one siteThe main determinant of spatial and temporal patterns  variation in vent flowResults in variations in:• Temperature• Chemical composition of the fluid • Bacterial productionAbundance and diversitySpatial patternsWithin vent fieldsDiffuse flows: density and composition decrease concentricallye.g. EPR (e.g. 9 ºN) Tubeworms at vent openings: the obturaculum has to be exposed to absorb H2S and O2 in big clusters or small tufts Mussels grow everywhere form patches or beds (100s-1000s of individuals) Clams in cracks (for ideal positioning of foot and siphon) between lava pillows or on sheets away from high temperatures in areas of low fluid flux; Crabs and fish very motile within or near animal clumps to distances of up to 500 mEast Pacific Rise – 9 ºN Tubeworm zoneBivalve zoneSerpulid zonePeripheryShank et al. (1998)Microbialmaterial32 months:Riftia overtakingTevnia11 months:Tevnia42 months55 monthshttp://www.nature.com/news/2010/100519/pdf/465284a.pdf“Everything is everywhere, but theenvironment selects” Stepping stone model  A population