Sediments

SedimentsSedimentsTypes of substrates: hard, softTypes of substrates: hard, soft

Types of sedimentsTypes of sedimentsClastics: abioticClastics: abioticCarbonates: abiotic, bioticCarbonates: abiotic, biotic

Sediment distribution in the oceansSediment distribution in the oceans

Importance of sediments to Importance of sediments to organisms, ecosystems, and chemistryorganisms, ecosystems, and chemistry

Substrate typesSubstrate types

Hard bottoms: rocks, Hard bottoms: rocks, hardgrounds, hardgrounds, other organisms, and other organisms, and artifical substratesartifical substrates

Energy: waves, currentsEnergy: waves, currentsEpibiosisEpibiosis

Substrate typesSubstrate types

Soft bottoms: muds, sands, gravelsSoft bottoms: muds, sands, gravelssemi-hard to soupysemi-hard to soupyEnergy determines grain sizeEnergy determines grain sizeInfauna and epifaunaInfauna and epifaunaBioturbationBioturbationOxygenation and anoxiaOxygenation and anoxia

Sediment propertiesSediment properties

Texture = size assortmentTexture = size assortmentMaturity = clay amount, sorting, roundnessMaturity = clay amount, sorting, roundness

Clastic (lithogenous) Clastic (lithogenous) sedimentssediments

Pebbles, sand, silt, clayPebbles, sand, silt, clayAbiotic, but can have biotic help in weatheringAbiotic, but can have biotic help in weatheringWeathered rocks (chemical and physical)Weathered rocks (chemical and physical)

sedimentdeposition

weathering

sedimentaryrock

lithification

metamorphicrock

igneousrock

recycle

recycle

P, T

The Rock CycleThe Rock Cycle

Sediment DepositionSediment DepositionParticles into drainage basins then into Particles into drainage basins then into oceansoceansParticle size is determined by energy of Particle size is determined by energy of transporttransport

FW input, storm transportFW input, storm transportException: iceException: ice

Distance from shore: deposition determined Distance from shore: deposition determined by by

amount of input, size of particles, amount of input, size of particles, energyenergy

Carbonate sedimentsCarbonate sediments

Calcium carbonate: CaCO3: formation and Calcium carbonate: CaCO3: formation and dissolutiondissolution

CaCOCaCO33 + H + H22O + COO + CO22 ↔↔ Ca Ca2+2+ + 2HCO3 + 2HCO3--

Calcium carbonate + water + carbon dioxide Calcium carbonate + water + carbon dioxide ↔↔

calcium + bicarbonate calcium + bicarbonate

Carbonate sedimentsCarbonate sedimentsAbiotic precipitation (rare) Abiotic precipitation (rare) Biotic precipitation: shells, etc.Biotic precipitation: shells, etc.Soft substrates, grain types: Soft substrates, grain types:

peloids, pelletspeloids, pelletsOoid sandsOoid sandsShell debrisShell debrisHalimedaHalimeda


Weathering: algal boringsWeathering: algal boringsbreakage breakage dissolutiondissolution

Role of CO2 and anthropogenic effectsRole of CO2 and anthropogenic effects


Cambrian explosion: 535 MYCambrian explosion: 535 MY

Ocean sediment Ocean sediment distributiondistribution

Tropics: Tropics: Carbonate, clastics on shelfCarbonate, clastics on shelf

Polar regions:Polar regions:Cold carbonates, ice float and boulder dropsCold carbonates, ice float and boulder drops

DepthDepthEnergyEnergyProximity to landProximity to landChemistryChemistry

Shallow sedimentsShallow sedimentsVariable sed ratesVariable sed rates

Relict sedimentsTurbiditesGlacial depositsStromatolitesStromatolitesReefsReefs

Deep sedimentsDeep sedimentsLow sed ratesLow sed rates

Abyssal clayAbyssal clayOozesOozes

Organic detritusOrganic detritusDustDust

Phosphate nodulesPhosphate nodules

Sediments and Sediments and OrganismsOrganisms

Benthos versus Nekton, PlanktonBenthos versus Nekton, PlanktonSoupy to firm bed: different organismsSoupy to firm bed: different organisms

Sessile versus vagileSessile versus vagileEpifauna, infaunaEpifauna, infauna


Organisms modify environmentOrganisms modify environmentBioturbationBioturbationReefsReefs


Feeding stragegies:Feeding stragegies: filter feeding, filter feeding, deposit feeding,deposit feeding, scavenging, predationscavenging, predation


Larvae, adults, and recruitmentLarvae, adults, and recruitmentMany benthic organisms have planktic larval Many benthic organisms have planktic larval

stagestageSettlement and metamorphosis cuesSettlement and metamorphosis cues

Sediments and Sediments and EcosystemsEcosystems

Stratified sediments versus bioturbationStratified sediments versus bioturbationGrain size effectsGrain size effectsEnergy effectsEnergy effects


Microbial loop; detrital food chain and nutrient Microbial loop; detrital food chain and nutrient recyclingrecycling

Important part of ecosystem in shallow waterImportant part of ecosystem in shallow waterBenthic singe-celled algaeBenthic singe-celled algae


SuccessionSuccession

Environmental perturbationEnvironmental perturbationPredictable: seasonality (T, precipitation)Predictable: seasonality (T, precipitation)Unpredictable: large storms, anthropogenic Unpredictable: large storms, anthropogenic

effectseffects

Sediments and Sediments and ChemistryChemistry

Nutrient recycling: microbial loop, algaeNutrient recycling: microbial loop, algaeNutrient, carbon sinkNutrient, carbon sinkSediments buffered from salinity changesSediments buffered from salinity changesAnoxia at depthAnoxia at depthToxin filterToxin filter

Pollution trapPollution trap

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Sediments