Primary productivity

Primary production

Rate at which energy is shored in organic matter

- Photosynthesis

- Chemosynthesis

Primary production can either be...

Photosynthesis

Solar radiation

Chemosynthesis

Chemical reactions

99.9%

.... of the ocean's biomass relies directly or indirectly on photosynthesis for food

cellular respiration

All organisms do ...

Gross Primary Production (GPP)

The total amount of photosynthetically fixed carbon

Net Primary Production (NPP)

The amount of photosynthetically fixed carbon available to the first heterotrophic level

respiration of the autotrophs

NPP = GPP -

50 Gt C y-1

Gross primary production in ocean is about...

- Central gyres: Low

- Equatorial and coastal region: High

- Polar regions: Moderate/high

In the Global Primary Production:

- Collect water

- Incubate

- Measure O2

- Add radioactive carbon tracer

What can they do to measure primary production?

satellites

They can monitor ocean color with ...

Photosynthetic phytoplankton

... use green pigment chlorophyll

SeaWifs (Sea-viewing WideField of View Sensor)

... satellite sensor collected ocean color data 1997-2010

MODIS (Moderate Resolution Imagery Spectroradiameter)

What satellite do we use currently? (It measures 36 spectral frequencies)

- Anthophyta

- Macroscopic algae

- Microscopic algae

- Photosynthetic bacteria

What are the types of photosynthetic marine organisms (doing photosynthesis in the ocean)?

- Seed-baring plants

- Restricted to shallow coastal waters

- Only seagrasses grow fully submerged in sea water

- Marsh grasses and mangroves tolerate salty roots but flower in air

What are anthophyta?

- Large algae

- Brown (Phaeophyta)

- Red (Rhodophyta)

- Green (Chlorophyta)

What are macroscopic algae?

- Small algae

- Chrysophyta: Diatoms and Coccolithophores

- Pyrrophyta: Dinoflagellates

What are microscopic algae?

Photosynthetic bacteria

May be responsible for half of the total photosynthetic biomass in oceans. They are very important

Solar radiation and Nutrient availability

What are some factors affecting primary production?

- Uppermost surface seawater and shallow seafloor

- Compensation depth

-Euphotic zone

Solar radiation is dealing with...

Net photosynthesis becomes zero

What is compensation depth?

From surface to about 100 meters (330 feet)

What is euphotic zone?

- Nitrate, phosphorus, iron, silica

- River runoff

- Upwelling

- Recycling

What are some factors dealing with nutrient availability?

Upwelling and Nutrient supply

Flow of deep water to surface Cooler, deep seawater is nutrient rich. Areas of coastal upwelling are sites of high productivity. (ex: western continental margins)

- Winter darkness

- Summer sunlight

- Phytoplankton (diatom) bloom seasonally

- Zooplankton (krill) productivity follows

- Isothermal waters

- Stratification from ice

- Plankton remain at surface

- Animals migrate to feed on zooplankton

What are some factors of polar ocean productivity?

- Permanent thermocline is barrier to vertical mixing

- Low rate of primary productivity (lack of nutrients)

- Permanent thermocline prevents mixing of surface and deep water

What are some factors of tropical ocean productivity?

High primary productivity in areas of equatorial upwelling, coastal upwelling and coral reefs

What are some factors of high productivity in tropical oceans?