Life in the Estuary:Physical and Chemical

Adaptations

Physical and Chemical Features of the Estuary

Physical ChemicalTidal flow/current

Storms/wave action/erosion

Staying putTemperature

Extremes Desiccation Not freezing

SalinityTidal influenceRainfallDroughtSnow melt

Organism internal maintenanceOsmosis

FundamentalsOsmosis: Diffusion of a

liquid (water) through a semipermeable membrane (gill, skin, etc) from and area of relatively lower osmotic concentration to an area of relatively higher osmotic concentration in an attempt to equalize both concentrations For example: Fish have internal

osmotic concentration Approx 1/3 of seawater. As a result, freshwater fish are constantly urinating and saltwater fish are constantly drinking.

Factors that Influence ChangesPhysical Chemical

Moon phase Alters tidal amplitude (speed)

Weather Storms may cause severe wave

actionRainfall

May increase (or decrease) currents

Snowmelt Spring melts often increase

flowGlobal Warming

Sea level rise may result in different current patterns

Moon Phase Tidal amplitude may increase

(or decrease) distance of salt wedge intrusion

Weather Storms may alter mixing

Rainfall Dilution of salinity

Snowmelt Dilution of salinity

Global Warming Some species have

temperature dependent sex determination (Sea Turtles)

Physical AdaptationSalinity/Exposure

Flow

MoveSwim (i.e. fish)Fly (i.e. birds)Burrow (i.e.

crabs)“Clam up”

(i.e. clams/oysters)

ExcretionGrasses

Go with current Fish eggs Plankton Algae Crabs

Sessile Attach using

natural cement Oysters/

barnacles Attach with large

and/or intricate roots Kelps and

grasses Epiphytes

TemperatureMoveSwim (i.e. fish)Fly (i.e. birds)Burrow (i.e.

crabs)“Clam up”

(i.e. clams/oysters)

DormancyPlants

Chemical AdaptationSalinity

OsmosisConstant battle

against the forces of diffusion

TemperatureDormancyPlants

Antifreeze?fish