ESTUARIESESTUARIES

What is an estuary?What is an estuary?

Area where fresh water meets salt waterArea where fresh water meets salt water

Semi-enclosedSemi-enclosed

Transition zoneTransition zone

Includes bays and lagoonsIncludes bays and lagoons

Chesapeake Bay, a coastal plain estuary

Nauset Barrier Beach – Cape Cod

San Francisco Bay, a tectonic estuary

Fjords

NJ ESTUARIESNJ ESTUARIES

What conditions affect estuaries?What conditions affect estuaries?

Rivers bring in:Rivers bring in:– Fresh waterFresh water– SedimentSediment– Pollutants from landPollutants from land

Oceans bring in:Oceans bring in:– SaltSalt– Sandy substrateSandy substrate– PlanktonPlankton

Estuary salinity

Mudflats

Estuaries are also Estuaries are also affected by:affected by:

TemperatureTemperature

SunlightSunlight

RainfallRainfall

Tides & CurrentsTides & Currents

ProductivityProductivity

Very high rate of productivityVery high rate of productivity

Water in estuary is nutrient-rich:Water in estuary is nutrient-rich:– Nutrients are carried from freshwaterNutrients are carried from freshwater– Insoluble in salt waterInsoluble in salt water

Many nutrients are good for producersMany nutrients are good for producers

OrganismsOrganismsSome are permanent part of estuary Some are permanent part of estuary communitycommunity

Some come and go: plankton, salmon, Some come and go: plankton, salmon, birds, horseshoe crabsbirds, horseshoe crabs

Some land animals that interact with Some land animals that interact with aquatic organismsaquatic organisms

TYPES OF COMMUNITIESTYPES OF COMMUNITIES

Open WaterOpen Water

Mud flatsMud flats– Exposed at low tide Exposed at low tide

Salt marsh (temperate)Salt marsh (temperate)– Partially flooded at high tidePartially flooded at high tide

Mangrove forestMangrove forest– Tropical equivalent of salt marshTropical equivalent of salt marsh

Mud flat

Salt Marsh

Mangrove forest

HUMAN IMPACTHUMAN IMPACTCoastal developmentCoastal development

PollutionPollution

DredgingDredging

Clearing LandClearing Land– ErosionErosion