Marine Ecology: Marine Ecology: Individuals and Individuals and

PopuationsPopuations

IndividualsIndividualsWater column zonationWater column zonationDealing with life in waterDealing with life in water

Light, Nutrients, SpaceLight, Nutrients, Space

PopulationsPopulationsThe Species definitionThe Species definitionLarval strategies and RecruitmentLarval strategies and RecruitmentEndangered speciesEndangered species

Water Column: Vertical Water Column: Vertical ZonationZonation

Light, resources importantLight, resources important

Shallow water, continental shelves: many neighborsShallow water, continental shelves: many neighbors

Open ocean: All organisms mobileOpen ocean: All organisms mobileUncoupled from the benthosUncoupled from the benthosSchools versus individualsSchools versus individuals

Deep ocean:Deep ocean:Mobile in water columnMobile in water column

““Feed or Breed”Feed or Breed”Deep benthosDeep benthos

Life in the Ocean: Life in the Ocean: BiogeographyBiogeography

Benthos usually limited to regionBenthos usually limited to regionSome fish, mammals: all over oceanSome fish, mammals: all over ocean

Factors that affect biogeography:Factors that affect biogeography:Resource requirements: T, light, productivity, spaceResource requirements: T, light, productivity, space

Larval dispersal rates, time in water columnLarval dispersal rates, time in water columnOcean currents, continent arrangement/ barriersOcean currents, continent arrangement/ barriers

Interaction with other speciesInteraction with other species

Anthropogenic effectsAnthropogenic effects

Life in Water: LightLife in Water: LightLight very necessary to photosynthetic organismsLight very necessary to photosynthetic organisms

Plants, algae, cyanobacteria, symbiotic relationshipsPlants, algae, cyanobacteria, symbiotic relationships

Day: photosynthesis:Day: photosynthesis:Light + CO2 + Nutrients --> Sugars (E) + 02 (Released)Light + CO2 + Nutrients --> Sugars (E) + 02 (Released)

Night: respirationNight: respirationO2 used by plantsO2 used by plants

Animals: Light is necessaryAnimals: Light is necessaryDirect: sightDirect: sightIndirect: trophic pyramidIndirect: trophic pyramid

Life in Water: NutrientsLife in Water: Nutrients

Plants: absorb from waterPlants: absorb from waterNO2, NO3, NH4NO2, NO3, NH4Iron, phospherous, potassiumIron, phospherous, potassiumNutrients can be limiting!Nutrients can be limiting!

Animals: Animals: consume other organismsconsume other organismsdecrease efficiency with decrease efficiency with increase in trophic levelincrease in trophic level

Microbial loop: recyclerMicrobial loop: recyclerBreakdown of detritus Breakdown of detritus --> release nutrients--> release nutrients

Life in Water: SpaceLife in Water: SpaceNot as important for mobile organisms??Not as important for mobile organisms??

Sessile organism: whole life on bottomSessile organism: whole life on bottomSpace to grow, consume, breedSpace to grow, consume, breedCan be limitingCan be limiting

Stone CrabStone Crab

Predator on oysters on Florida Gulf coastPredator on oysters on Florida Gulf coast

Space: burrows, shelters in tidal zoneSpace: burrows, shelters in tidal zoneCan be fairly dense population if enough Can be fairly dense population if enough

oystersoysters

Variety of predation behaviors per individualVariety of predation behaviors per individualEat on site versus carry away and eat in Eat on site versus carry away and eat in

privacyprivacyEat “continuously” versus every few daysEat “continuously” versus every few days

Nutrients direct from oysters; oysters from filter Nutrients direct from oysters; oysters from filter feeding on particulate matter; particulate matter feeding on particulate matter; particulate matter ultimately from dissolved nutrientsultimately from dissolved nutrients

Light is necessary: visual sense is goodLight is necessary: visual sense is goodPredator avoidance: birds, humansPredator avoidance: birds, humans

PopulationsPopulationsGroup of monospecific organisms that reproduceGroup of monospecific organisms that reproduce

Small area to large areaSmall area to large areaOpen or closedOpen or closed

Several populations with genetic contact: metapopulationSeveral populations with genetic contact: metapopulation

Species: can be metapopulationSpecies: can be metapopulation

The Species ConceptThe Species Concept

Species:Species:Biology: able to reproduceBiology: able to reproducePaleontology: morphologyPaleontology: morphology

--> --> Are there problems with these definitions?Are there problems with these definitions?

Species potential range Species potential range actual range actual range

New species: mutation, allopatric speciationNew species: mutation, allopatric speciation

The idea of natural selection, “Survival of the Fittest”The idea of natural selection, “Survival of the Fittest”

Life HistoryLife History

r-selected speciesr-selected speciesmany offspring, no parental inputmany offspring, no parental input

K-selected speciesK-selected speciesfewer offspring with more care or parental inputfewer offspring with more care or parental input

r- versus K- selection is relative.r- versus K- selection is relative.

Live birth rare; most organisms: larval stageLive birth rare; most organisms: larval stageRecruitmentRecruitment

Life mode: Clustering, gregarious behavior, pods, solitary Life mode: Clustering, gregarious behavior, pods, solitary

Death: recycled back into nutrientsDeath: recycled back into nutrients

Larval Strategies and Larval Strategies and RecruitmentRecruitment

Almost all marine organisms: larvaeAlmost all marine organisms: larvaeInvertebrates, fishInvertebrates, fish

Larvae: Larvae: Planktotroph: long time in water column, feedingPlanktotroph: long time in water column, feedingLecithotroph: settle quickly, “yolk” with nutrientsLecithotroph: settle quickly, “yolk” with nutrients

Larval survivalLarval survivalRecruitmentRecruitment

New individuals into populationNew individuals into populationMetamorphosis/settlement, survival, geneflowMetamorphosis/settlement, survival, geneflow

* Most don’t * Most don’t survive!survive!

Population dynamicsPopulation dynamics

Interannual and intra-annual variationInterannual and intra-annual variationLarval mortality, juvenile mortality, adult mortalityLarval mortality, juvenile mortality, adult mortality

Factors that regulate population size:Factors that regulate population size:Limiting resourcesLimiting resourcesInteractions with other speciesInteractions with other species

Carrying capacityCarrying capacity

Conchs aggregating in food search

Example: Example: EvechinusEvechinus echinoid in New Zealand echinoid in New Zealand

fjordfjord

Live in shallow water, fully marineLive in shallow water, fully marineMigrate into fjord on full moon, neap tide, springMigrate into fjord on full moon, neap tide, springAggregate and spawnAggregate and spawnLarvae in estuary; into oceanLarvae in estuary; into oceanEventually metamorphose and settle: few days, not farEventually metamorphose and settle: few days, not far

Closed population?Closed population?

Salmon: open or closed population?Salmon: open or closed population?

Exotic speciesExotic speciesIntroduced species: Introduced species: natural or human-causednatural or human-caused

Many introduced organisms Many introduced organisms don’t make itdon’t make it

Those that do are oftenThose that do are oftencatastrophic to ecosystemscatastrophic to ecosystems

Outcompete local speciesOutcompete local speciesDecreased predation pressureDecreased predation pressureNiche expansionNiche expansion

MusselLittorina littorina sp.

Population numbers too lowPopulation numbers too lowin danger of extinction b/c in danger of extinction b/c

not not enough gene flowenough gene flow

ConservationConservationGoal: to increase population, Goal: to increase population,

gene flowgene flowTake off fishing pressureTake off fishing pressureTake pressure off resourcesTake pressure off resourcesSanctuarySanctuaryTissue samplesTissue samples

In the marine realm, how can this In the marine realm, how can this be problematic? How is be problematic? How is conservation different for a clam, conservation different for a clam, a fish, and a whale?a fish, and a whale?

Endangered SpeciesEndangered Species