Organisms

Have optimal survival temperatures.

They also have depth adaptations, such as bioluminescence for protection or attraction ofo prey.

Vertical distribution of ocean properties

Pressure is linear, but salinity, temp, density, light intensity, nitrate is not.

--> makes ocean stably stratified with generally warm, nutrient poor water at the surface and cold, nutrient rich water at depth.

CTD

Measures temperature, pressure, conductivity.

Oceans

Pelagic Environments

Different environments as depth increases in the sea.

- Epipeplagic, mesopelagic, mesopelagic, deep pelagic, deep-sea bottom.

Considerations for life in the sea

- Currents

- Buoyancy/flotation

- Temperature

- Salinity

- Pressure

- Light

- Nutrients/food availability

Phytoplankton

Perform photosynthesis. They also respire.

- Cyanobacteria

- Diatoms

- Coccolithophores

- Dinoflagellates

- Green Algae

Ocean Life

Nitrate

Vast Reservoir of Nitrate in the Deep Ocean

--> Leads to phytoplankton growth.

Ekman Divergence

Description

Coastal Upwelling

Bring nitrate to different regions in ocean.

Cyanobacteria

Most abundant photosynthetic organisms on Earth.

- Prochlorococcus (in tropical regions)

- Synechococcus

- Trichodesmium (grow using N2 gas) -- play an important role in replenishing nitrogen content oof the ocean.

Diatoms

- Dominate blooms in nutrient rich conditions

- Fast growing, fast sinking

- Produce amazing shells out of silica.

Coccolithophores

- Relatively small

- Abundant blooms in temperate regions

- Produce calcium carbonate shells that sink rapidly.

- Important for global carbon cycle.

Biological Carbon Pump

Phytoplankton feed higher trophic levels and reduce the concentration of atmospheric CO2, pumping it to the sea floor.

Zooplankton (ie dinoflagellates)

Have variety of sizes, life cycles, and feeding strategies. Can be partially photosynthetic (ie dinoflagellates).

Marine Trophic Levels

--> trophic transfer efficiency ~10% (because rest is transferred to heat).