Aquatic Ecosystems

Limiting Factors (freshwater)

availability of sunlight, concentration of nutrients and dissolved O2

Limiting factors (saltwater)

light availability, O2 levels, water movement, salinity, density, pH

Plankton

free flowing, small/micro, migrate vertically daily or seasonally Ex.) phytoplankton

Nekton

larger, stronger swimming organisms Ex.) fish, octopus, marine mammals

Benthos

bottom dwelling, fixed to one spot, burrow Ex.) oysters, worms, crawfish

Littoral Zone

most productive, emergent vegetation, aquatic plants, algae, tadpoles, turtles

Limnetic zone

phytoplankton, zooplankton, large fish, less vegetation—>depth

Profundal Zone

no plants or algae—>no light, food drifts from other zones, bacteria decompose dead organisms using up O2 liberating minerals, rich, anaerobic (no O2)

Hypotnic

little O2

Thermal stratification

temp changes sharply with depth, caused by light penetrating at different depths

Intertidal

between high and low tide, biologically productive, stressful for organisms (sandy beach, rocky shore)

Benthic

ocean floor, mostly sediment, bacteria

• shallow water—>sea grass, kelp, coral

• deep water—> abyssal, hadal

Pelagic

Neritic Province: shallow waters (lots of plankton)

• shoreline—>200m

Oceanic Province: DEEP

• cold, high pressure, marine snow