• Upwelling (coastal or otherwise) brings deep water to the surface (recall exercise on Tues.)• Deep water has high nutrient concentrations, so primary production increases. (What is primary production? Stay-tuned)•Primary production is traced by chlorophyll (green stuff in plants).

Upwelling, primary production, and iron fertilization: a short trip (with

detours) through the ocean ecosystem.

Model nitrate concentrations

Courtesy P.MacCready, UW

Primary Productivity: What is it?• Primary productivity is the synthesis of

organic molecules from inorganic substances.

We call organisms which perform primary productivity autotrophs (auto=self + trophe=nourishment.

• We’re all familiar with primary producers on land: they are the plants!

• Most oceanic primary production is accomplished by marine phytoplankton, also plants, but not stationary in one place.

• Phytoplankton photosynthesize to create organic molecules with 4 key ingredients:

• Sunlight

• Water

• CO2 (carbon dioxide)

• Nutrients (inorganic substances)

Primary Productivity: What is it?

Primary Productivity: What is it?

• All phytoplankton also use a pigment called chlorophyll to help trap sunlight

• Chlorophyll is useful for tracking area of primary production & phytoplankton – visible to satellites!

• The basic reaction is:

6CO2 + 6H20 + (sunlight & chlorophyll) --> C6H12O6 + 6O2

Coscinodiscus diatom (center), Ditylum diatom chains (sides)

Centric and pennate diatoms – most common phytoplankton.

Asterionella diatoms

Diatom division with different size daughter cells.

Dinoflagellates – both auto- & heterotrophes: Some dangerous (Gymnodinum, Gonyaulax- “red-tide”/PSP) and some pretty (Noctiluca - bioluminescent)

Phytoplankter Coccolithophore’s calcareous plates

Primary Productivity: A multi-stage conversion process of energy and matter

• Primary production converts solar energy and inorganic nutrients into food for the entire ecosystem.

• It’s a critical part of the global carbon cycle.

© 2002 Brooks/Cole, a division of Thomson Learning, Inc.

Carbon Cycle

Copepods and euphausids – common zooplankton.

Antarctic krill Eupausia superba – food for the mighty baleen whales.

Some comb-jellies (ctenophores), and tunicates (Salpa & Doliolum).

Above is one version of a food web with trophic levels. Linked here is another graphical version (by Amity Femia)

An in-class group exercise• See hand-out•Go to SAL so all groups have a super-cool new computer.

http://seawifs.gsfc.nasa.gov/cgi/monthly_climatologies.pl?TYP=bios