coastal

The Oceans, Coastal Processes The Oceans, Coastal Processes and Landformsand Landforms

OverviewOverview

OceansOceans Coastal SystemsCoastal Systems

ComponentsComponents ActionsActions OutputsOutputs

Biotic Biotic ComponentsComponents

OceansOceans Chemical compositionChemical composition

WaterWater Salts: dissolved ionic compoundsSalts: dissolved ionic compounds

ClCl--, Na, Na++, Mg, Mg2+2+, SO, SO442-2-, Ca, Ca2+2+, K, K++, Br, Br--

Salinity (parts per hundred)Salinity (parts per hundred) Average: 3.5% Average: 3.5% Brine: >3.5%Brine: >3.5%

Areas with high rates of evaporationAreas with high rates of evaporation Brackish: <3.5%Brackish: <3.5%

Areas at the mouths of rivers; estuariesAreas at the mouths of rivers; estuaries

Atmospheric gasesAtmospheric gases NN22, CO, CO22, O, O22

Physical structurePhysical structure

Coastal System Coastal System ComponentsComponents

Solar EnergySolar Energy Atmospheric windsAtmospheric winds

Create ocean Create ocean waveswaves Climatic regimesClimatic regimes

Gravitational EnergyGravitational Energy TidesTides

Characteristics of coastal rockCharacteristics of coastal rock Human activitiesHuman activities TerminologyTerminology

Littoral zoneLittoral zone Shoreline Shoreline CoastCoast

Coastal System Coastal System ActionsActions

Erosion, transport and Erosion, transport and deposition occur deposition occur through the action of through the action of tides and breaking tides and breaking waveswaves

TidesTides Gravity: Moon and SunGravity: Moon and Sun

Tidal powerTidal power Spring tides, neap tidesSpring tides, neap tidesLunar Phases

Tide Tide PredictorPredictor

Lunar PhasesTide Predictor

Lunar PhasesTide PredictorTide Predictor

Lunar PhasesLunar PhasesTide PredictorTide Predictor

Lunar PhasesLunar PhasesTide PredictorTide Predictor

WavesWaves Solar > Wind > WaterSolar > Wind > Water Each wave crest is a pulse of Each wave crest is a pulse of

energyenergy performs the erosive workperforms the erosive work

Wave refraction and coastal straighteningWave refraction and coastal straightening erosiveerosive

Longshore current and beach driftLongshore current and beach drift erosion, transportation, and depositionerosion, transportation, and deposition

Coastal System OutputsCoastal System Outputs Erosional processes and landformsErosional processes and landforms

Rugged, high relief, tectonically activeRugged, high relief, tectonically active wave cut platformwave cut platform

Transport: longshore currents, beachdriftTransport: longshore currents, beachdrift Depositional processes and landformsDepositional processes and landforms

Land with gentle relief, providing sedimentsLand with gentle relief, providing sediments beachesbeaches barrier spitbarrier spit bay barrierbay barrier tombolotombolo barrier islands – often supports vegetationbarrier islands – often supports vegetation

Erosional LandformsErosional Landforms

Depositional LandformsDepositional Landforms

Biological ProcessesBiological Processes Coral reefsCoral reefs

Coral polypsCoral polyps Secrete CaCOSecrete CaCO33

Symbiotic with algaeSymbiotic with algae Specific ecological niche – sensitive to Specific ecological niche – sensitive to

changeschanges 10 – 55 meters depth10 – 55 meters depth 2.7 – 4.0 % salinity2.7 – 4.0 % salinity 1818oo – 29 – 29oo C water temperature C water temperature clear, sediment free waterclear, sediment free water sea-level rise and warming of ocean waters sea-level rise and warming of ocean waters

threatens coral reefsthreatens coral reefs If global trends were to stop immediately, it is If global trends were to stop immediately, it is

estimated that 50% of the world’s coral reefs will dieestimated that 50% of the world’s coral reefs will die

Coastal WetlandsCoastal Wetlands

Salt marshes: Poleward (N or S) of 30Salt marshes: Poleward (N or S) of 30oo latitude latitude Often form in intertidal zoneOften form in intertidal zone Often occur on barrier islandsOften occur on barrier islands

Mangrove swamps: Between 30Mangrove swamps: Between 30oo N and S N and S latitudelatitude Grow on sediment accumulationGrow on sediment accumulation Serve to shelter young fish, important for conservationServe to shelter young fish, important for conservation

VegetationVegetation hydrophytichydrophytic halophytichalophytic

Estimated 40-80% loss over the last 10,000 Estimated 40-80% loss over the last 10,000 yearsyears

IssuesIssues

Oceans poorly understoodOceans poorly understood Humans are still hunter-gatherers on the Humans are still hunter-gatherers on the

oceansoceans We use the oceans as our universal dumpWe use the oceans as our universal dump

Shoreline developmentShoreline development Development occurs on these constantly Development occurs on these constantly

shifting landscapesshifting landscapes Climate changeClimate change

Rising seal levelsRising seal levels Rising ocean temperatureRising ocean temperature