EEMB 120 Lect 6
EEMB 120 Lect 6 MCDB 101A
Popular in Molecular Genetics I
Popular in Biology
Mrs. Jazmyne Kulas
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This 7 page Bundle was uploaded by Aria Ghasemizadeh on Friday October 16, 2015. The Bundle belongs to MCDB 101A at University of California Santa Barbara taught by Thrower in Fall2014. Since its upload, it has received 60 views. For similar materials see Molecular Genetics I in Biology at University of California Santa Barbara.
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Date Created: 10/16/15
Reminder Midterm Exam 1 This Thursday Oct 15 and walk We is cheese I I Pa 59 A TF39IID SELIETIOH IV EITIHT N9 quothi THE in Swill A CHIHI THAT THE 5 kn Our Education um quot gt4 The Epipelagic Zone Life in a Constantly Moving Medium htt wwwthemainecurrentcomcruisecruise bab The Epipelagic Zone Thin top layer of ocean where photosynthesis occurs EPIPELA GIC PHOTIC 653530 lt 5 of ocean volume The Epipelagic Zone Thin top layer of ocean where photosynthesis occurs typically 100 200 m deep Know comparatively little amp difficult environment to study Studying the Epipelagic Zone Life in a moving fluid LOGISTICAL CONSTRAINTS Organisms transported by current ow plankton or can transport themselves nekton All are constantly changing location 1 Experimentation Difficult Limited types of experiments that can be done The Epipelagic Zone The Epipelagic Zone Studvinq the Epipelagic Zone LOGISTICAL CONSTRAINTS 1 Experimentation Difficult a 2 Sampling Challenging a Done remotely Many devices sample selectively Many organisms delicate crushed or killed Approaches to Studying the Epipelagic Given constraints how is the Epipelagic Zone explored 1 Field Experimentation Possible to perform certain kinds of experiments a Manipulate whole water masses Example does Iron limit production in epipelagic zone Iron granules dispensed by ship in patches several kms in size Phytoplankton production followed in enriched amp control patches b In Situ Mesocosm experiments b Local environment constantly changing No boundaries except shores Organisms constantly shift position currents upwelli g Shifts can be rapid day I mght even hourly OVerSHSi Giant containers that capture portion of water column that can be 6 SPeCieS cemPOSitiOrl highly variable at any locality htm manipulated alter trophic composition nutrient regimes etc Frustrating if goal is to study a particular set of organisms Carl have replicates or many different treatments Diel vertical migration of a zooplankter The Epipelagic Zone The Epipelagic Zone Approaches to Studying the Epipelagic Approaches to Studying the Epipelagic 1 Field Experimentation 1 Field Experimentation 2 Extrapolate from Freshwater Systems 2 Extrapolate from Freshwater Systems Easier to manipulate entire lakes lakes with amp without planktivorous shes 339 EXtrapOIat from Lab to new Extrapolation has value but done with caution 4 CorrEIatlon Approach Processes controlling Epipelagic Zone not necessarily the same as in lakes Explore relationship between variables using observational data 3 Extrapolate from Lab to Field Use caution correlation does NOT imply causation Done in all ecological fields but also problematic a Realism an issue Difficult to keep Epipelagic Organisms alive much less behaving amp functioning normally in lab b Scaling Up an issue Spatial amp temporal scales very different between lab study amp real world 1 Production Nutrients Scaling The Epipelagic Zone The Epipelagic Zone Trophic Structure of the Epipelggic Zone Trophic Structure of the Epipelggic Zone A Food webs short and simple A Food webs Epipelagic Zone Food web is microbe based Phytoplankton gt Zooplankton gtNekton One drop of seawater contains 1 million bacteria 10 million viruses Relatively few 30 consumers Genetics amp mIcroscopy accelerate understandlng of mIcrobe world 1 BATH131W umn mm g wm m 1 l a tuning 4 mm m 7 39 I g a EHM 112 u Human B hhphycm Phytoplankton Zooplankton Zooplanktivores a 7quotquot m i AM m I mmlooamw FIDPDND r r mum ammiwH e ml WWWM39 mallum mirth ummchmm 3 u ai a quot39 st e r wm 5 Mail at 39 39 39 I i 39 l 39I V 39 l Uquot 39 quot c h I ngmmu mm quotW WW mammary nimjmmmnma W99 1 39 WWW M m quotTm e Tlln wm m 7 mwhmmm39l Cocolithophores The Epipelagic Zone The Epipelagic Zone Trophic Structure of the Epipelggic Zone PthOD39 nkton quot1399 the world A Food webs Epipelagic Zone Food web is microbe based 39 FDI logs 0f C02 PVOduce 90 0f Earth s Ozand help create c ou s One drop of seawater contains 1 million bacteria 10 million viruses Genetics amp microscopy accelerate understanding of microbe world 39 meed by phosphorous n39trogen s39l39ca d39atoms Iron trace elements Viroplankton poorly understoodlt3o nm to 3 pm most use bacteria to reproduce bacteriophages require hosts help recycle nutrients by lysing bacteria many killed by uv light 5 Bacterioplankton Factoid 1 Harness phytoplankton to control greenhouse gases Phytoplankton consume C02 when fixing carbon Phytoplankton is iron limited Seed ocean with iron to create phytoplankton blooms to take C02 12 of all Carbon in marine food webs goes through bacteria out of atmosphere lt 10 of marine bacterial species have been cultured Trophic forms Marine diatom Phytoplankton Autotrophic photosynthetic eg blue green algae 7 a Heterotrophic take up DOM or other bacteria Mixotrophic can photosynthesize amp feed Phytoplankton blooms from space Pelagibacter ubique SAR11 clade most abundant bacterium in world worldwide distribution smallest selfreplicating cell known Il micron The Epipelagic Zone Factoid 1 Harness phytoplankton to control greenhouse gases Southern Ocean Iron Release Experiment SOIREE released iron amp a tracer over 100 km2 monitored for 2 weeks so seeding ocean with Fe won t help sequester C02 Factoid 2 How phytoplankton helps create clouds UV light damages phytoplankton Phytoplankton produce chemical dimethylsulfoniopropionate DMSP as protection antioxidant DMSP breaks down to dimethylsulfide DMS DMS goes into air amp serve as nuclei for water droplets that form clouds got large phytoplankton bloom but carbon not transferred to deep ocean The Epipelagic Zone Pattern very high 1 production but relatively low phytoplankton standing stock Reason most 1 production consumed by epipelagic animals Plant Animal Biomass Ratio 1 Terrestrial Systems 1 gm Plant Biomass 0001 gm Animal Biomass 2 Epipelagic Systems1 gm Plant Biomass 20 gm Animal Biomass Biomass pyramids Grassland Epipelagic zone H Apex predators Predators Zooplanktivores Grazers Zooplankton Grass Phytoplankton The Epipelagic Zone Trophic Structure of the Epipelagic Zone A Food webs microbe based B Abundance largely controlled by physical processes particularly those influencing nutrient flux Strong bottom up control by nutrients primarily N P Fe Nutrients huge role in shaping abundance amp community structure Nutrients gt Phytoplanktonp Zooplankton gt Nekton What controls nutrient flux in Epipelagic Zone Nutrient source deeper waters where remineralization occurs Mixing upwelling amp turbulence moveinject nutrients into surface water Mixing gtNutrients gtPhytoplankton gt Zooplankton gtNekton 39 a u quot a r Mixing Upwelling Turbulence f r I n Apex predators a u 1 Zooplanktivores J J l I Zooplankton E Phytoplankton v I t I The Epipelagic Zone Pattern very high 1 production but relatively low phytoplankton standing stock Reason most 1 production consumed by epipelagic animals Plant Animal Biomass Ratio 1 Terrestrial Systems 1 gm Plant Biomass 0001 gm Animal Biomass 2 Epipelagic Systems1 gm Plant Biomass 20 gm Animal Biomass High animal biomass sustained by high primary production most eaten High primary production sustained by high nutrient flux High nutrient flux results from microbial activity amp physical transport processes a Phytoplankton Zooplankton The Epipelagic Zone Trophic Structure of the Epipelagic Zone A Food webs microbe based B Abundance C Distribution tied closely to physical amp chemical processes Set mostly by physiological tolerances Cooccurring species have similar tolerances to abiotic conditions Species have generalized niches Specialists amp highly coevolved biological interactions rare ie mutualism amp parasitism rare Movement Patterns of Epipelagic Organisms Phytoplankton bacterioplankton protists move horizontally by currents stay in upper layers Larger zooplankton amp smaller sh Larger sh and mammals move horizontally with current cruise long distances diel vertical migrations DVM The Epipelagic Zone Trophic Structure of the Epipelagic Zone A Food webs microbe based B Abundance C Distribution D Species Diversity iOW yet not incredibly low Epipelagic Zone covers gt 70 of Earth s surface but of species is low By comparison millions of species of terrestrial insects 4000 species of zooplankton worldwide 1200 are copepods Same number of fish species in entire Epipelagic Zone as in the Amazon River Basin Phytoplankton Copepods The Epipelagic Zone Movement Patterns of Epipelagic Orqgnisms 0 Horizontal Distributions Varies widely because different water masses have different physical l chemical attributes Water masses moved by currents Assemblage of organisms moves with its water mass 0 Diel Vertical Migrations Zooplankton stay at depth during day to avoid predators Travel to surface at night to feed on smaller plankton So many vertically migrating organisms can be tracked by sonar a 1 FE 11 Benin mi i Gulf Stream Water masses with different Temperature amp Salinity signatures The Epipelagic Zone Trophic Structure of the Epipelagic Zone D Species Diversity low Why is Species Diversitv so low 3 Primary Reasons 1 Low Speciation Rate a Species have high dispersal abilities amp rates lots of gene mixing b Geographic boundaries rare little opportunity for local adaptation The Epipelagic Zone The Epipelagic Zone Whv i Species Diversitv so low 3 Primary Reasons Epipe39iqic diVerSitV conundrum 1 Low Speciation Rate Given attributes of the Epipelagic Zone structureless homogeneous 2 Relatively little niche space why are there as many species as there are 3 Virtually quot0 PhySica39 Structure The Paradox of the Plankton GE Hutchinson b Environment very homogeneous few microhabitats Why so many species and Why isn t competitive exclusion operating Potential explanations 1 Succession Community assemblage in a water mass changes predictably through time 3 Species have broad generalized niches a Environmental unpredictably favors generalists b Most species have generalized diets c Specialized species rare eg very few mutualisms succeSSi quota39 Sta 9 Early Nutrients HIGH LOW Productivity HIGH LOW Dominated by Diatoms Dino agellates amp Cyanobacteria Ef ciency LOW HIGH need high nutrient flux The Epipelagic Zone The Epipelagic Zone Epipelagic diversity conundrum The Paradox of the Plankton Epipelagic diversity conundrum Potential explanations Successional Stage 1 Succession M w 2 Contemporaneous Disequ brium Horizontal Heterogeneity Nutrients HIGH LOW Much patchiness in assemblage compositions because Productivity HIGH LOW Many water masses at any given time D minated by Diamms Din agellat s amp Different patches at different succession stage Cyanobacteria Nutrient needs SIMPLE COMPLEX Exclusion does occur within a patch need vitamins trace metals Ef ciency LOW HIGH Mixmg reintroduces species amp nutrients resetting patch to earlier need high nutrient ux successional stage Spp RICHNESS SIMILAR SIMILAR quot quot Spp EVENNEss LOWER HIGHER DIVERSITY LOWER HIGHER Most species probably present most of the time Big shift in which species groups are most abundant among successional stages The Epipelagic Zone Epipelagic diversitv conundrum Potential explanations 1 Succession 2 Contemporaneous Disequilibrium 3 Thin Layer or Vertical Partitioning Hypothesis Vertical Heterogeneity Get sharp a T discontinuities with depth I Abundances of species highest at discontinuities Surface Different species at different discontinuities vertical partitioning Depth Below Temperature Salinity a T OReduced spatial overlap means reduced interspecific competition
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