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 CO 2 (carbon dioxide) Nutrients (inorganic substances) 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: 6CO 2 + 6H (sunlight & chlorophyll) --> C 6 H 12 O 6 + 6O 2

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) Linked here

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