Ecology 15Ecology 15Freshwater, Marine and Freshwater, Marine and

Wetland SystemsWetland SystemsGlobal Climate ChangeGlobal Climate Change

Ralph KirbyRalph Kirby

Freashwater and Estuarine Freashwater and Estuarine EcosystemsEcosystems

Water that falls on land and does not enter the soil or evaporate Water that falls on land and does not enter the soil or evaporate must create surface water systemsmust create surface water systemsGravity forms streams then riversGravity forms streams then riversThese create basins, ponds, lakes floodplains and wetlandsThese create basins, ponds, lakes floodplains and wetlandsWatershedWatershed– Area of land drained by a stream or riverArea of land drained by a stream or river

CatchmentCatchment– Ponds, lakes and wetlands that retain water for a long timePonds, lakes and wetlands that retain water for a long time

LoticLotic– Flowing water ecosystemsFlowing water ecosystems

StreamsStreamsRiversRivers

LenticLentic– Nonflowing water ecosystemsNonflowing water ecosystems

PondsPondsLakesLakesInland wetlandsInland wetlands

Lakes and PondsLakes and PondsMultiple originsMultiple origins– GlacialGlacial– TectonicTectonic– SubsidenceSubsidence– From rivers and streams by silting upFrom rivers and streams by silting up– AnimalsAnimals– HumansHumans

Inland depression holding standing waterInland depression holding standing water– Large range of depthsLarge range of depths

1 meter to 2000 meters1 meter to 2000 meters– Large range of sizesLarge range of sizes

< 1 hectare to >1000 square kilometers< 1 hectare to >1000 square kilometers

Ponds have rooted plants over most of areaPonds have rooted plants over most of areaLake and pond ecosystems have well defined boundariesLake and pond ecosystems have well defined boundaries– Dependent on light and therefore depthDependent on light and therefore depth

Affected by silt and phytoplanktonAffected by silt and phytoplanktonOxygen limitationOxygen limitation

– Littoral zoneLittoral zoneWhere light reaches the botomnWhere light reaches the botomn

– Limnetic zoneLimnetic zoneWhere light penetrates, but not to botomnWhere light penetrates, but not to botomn

– Frofundal zoneFrofundal zoneWater where light does not support photosynthesisWater where light does not support photosynthesis

– Benthic zoneBenthic zoneBottom zoneBottom zone

Littoral ZoneLittoral Zone– Greatest diversityGreatest diversity– SpecializationSpecialization– Many animal speciesMany animal species– Provides a large input of organic matter into the whole systemProvides a large input of organic matter into the whole system

Limnetic ZoneLimnetic ZoneDominated by planktonic organismsDominated by planktonic organisms– PhytoplanktonPhytoplankton– ZooplanktonZooplankton

Seasonal variationsSeasonal variationsLimited by lightLimited by lightPhytoplankton limits it’s own lightPhytoplankton limits it’s own light– Thus limnetic zone become shallower as summer progressesThus limnetic zone become shallower as summer progresses

Phytoplankton specialiation based on depth and Phytoplankton specialiation based on depth and temperaturetemperatureZooplankton can usually move and therefore may laos Zooplankton can usually move and therefore may laos be stratifiedbe stratifiedSpring and Autumn turnovers move plankton downwards Spring and Autumn turnovers move plankton downwards and organic matter upwardsand organic matter upwardsFish are usually top predatorsFish are usually top predators– Influenced by food supply, oxygen and temperatureInfluenced by food supply, oxygen and temperature

Profundal ZoneProfundal Zone

Limited life Limited life – Lack of oxygenLack of oxygen– Lack of lightLack of light– Low temperatureLow temperature

Some fishSome fish

Some plankton, especially zooplanktonSome plankton, especially zooplankton

Benthic ZoneBenthic Zone

Where decomposition occursWhere decomposition occurs

Great biological activityGreat biological activity

Dominated by anaerobic microorganismsDominated by anaerobic microorganisms

As it approaches the surface, it changesAs it approaches the surface, it changes– Influence of plants, water movement, light, etcInfluence of plants, water movement, light, etc

EutrophicationEutrophication

Input of organic Input of organic matter can matter can change structure change structure of a lakeof a lakeIncreases Increases planktonplanktonDecreases Decreases oxygenoxygenChanges Changes temperature temperature profileprofileAffects EpiimnionAffects EpiimnionHuman Human intervention is intervention is very important in very important in thisthis– Can occur Can occur

naturallynaturally– Fertilizers and Fertilizers and

addition of addition of exotic species exotic species can also cause can also cause thisthis

Flowing Water CommunitiesFlowing Water Communities

Velocity is very Velocity is very importantimportantGeography determines Geography determines the structure and the structure and speed of flowspeed of flowSpeed usually higher Speed usually higher nearer the sourcesnearer the sourcesSpeed is reduced on Speed is reduced on entering a larger body entering a larger body of waterof water– Silt dropSilt drop

Life adapts to the Life adapts to the speed of the streamspeed of the stream

Four major feeding Four major feeding groups in a stream groups in a stream

communitycommunity

Flowing water systems are a continuous communityFlowing water systems are a continuous communityFlowing water systems change from the headwaters to the mouthFlowing water systems change from the headwaters to the mouth– Vegetation changesVegetation changes– Plankton changesPlankton changes– Animals changeAnimals change

Dams have a major effect on flowing water systemDams have a major effect on flowing water system– Create lakesCreate lakes– Slows water flowSlows water flow

Changes spiralingChanges spiraling– Reduce floodingReduce flooding– Removes siltRemoves silt– Multiple Dams can compound effectsMultiple Dams can compound effects– Three Gorges ProjectThree Gorges Project

Freshwater eventually joins the marine environmentFreshwater eventually joins the marine environment– EstuaryEstuary– Sediment dropSediment drop– Mixed environmentMixed environment– SalinitySalinity– Water flow in both directionsWater flow in both directions

Marine EcosystemsMarine Ecosystems

Zonation and StratificationZonation and Stratification– Pelagic ZonePelagic Zone

Photic zonePhotic zone– LightLight

MesopelagicMesopelagic– Light limitedLight limited

BathypelagicBathypelagic– DarkDark

Neritic province – Continental ShelfNeritic province – Continental ShelfOceanic provinceOceanic province

– Benthic ZoneBenthic Zone

System varies with season and latitudeSystem varies with season and latitude

Surface of pelagicSurface of pelagic– Phytoplankton Phytoplankton

dominatesdominatesGreat diversity in Great diversity in species and sizespecies and size

– Zooplankton major Zooplankton major herbivoreherbivore

– Bacteria also Bacteria also importantimportant

– Fish very important Fish very important in Nekton provincein Nekton province

BenthosBenthos Unique WorldUnique World– Surface and Surface and

subsurface living subsurface living organismsorganisms

– Energy from Energy from decompositiondecomposition

– Energy from Energy from hydrothermal hydrothermal ventsvents

Black smokersBlack smokers– 300-450300-450ooCC

White smokersWhite smokers– ++300300ooCC

High in mineralsHigh in minerals

Hyperthermophilic Hyperthermophilic organismsorganisms

– BacteriaBacteria

– WormsWorms

SeashoresSeashores

Rocky shoreRocky shore– Complex environmentComplex environment

Wave actionWave action– AttachmentAttachment

TidesTides– How oftenHow often

OxygenOxygen

High diversityHigh diversitySandy or muddy shoresSandy or muddy shores– HarshHarsh

No place to attachNo place to attachLife is hiddenLife is hiddenBased on organic matterBased on organic matter

Rocky ShoreRocky Shore

Sandy shoreSandy shore

Complexity of a coastal ecosystemComplexity of a coastal ecosystem

Coral ReefsCoral Reefs

High productivityHigh productivity

Very high diversityVery high diversity

Mixture of coastal and deepwater systemMixture of coastal and deepwater system

WetlandsWetlandsArea covered with water and supporting aquatic plantsArea covered with water and supporting aquatic plantsVery wide variety of typesVery wide variety of types– Vary with periodicity of floodingVary with periodicity of flooding– Vary with saturationVary with saturation– Vary with oxygen availabilityVary with oxygen availability– SalinitySalinity– GeographyGeography

Global Environmental ChangesGlobal Environmental Changes

EvidenceEvidence

ResultsResults