Dr. Neil S. Suits

NASA/Goddard Space Flight Center, The SeaWiFS Project and GeoEye, Scientific Visualization Studio SeaWiFS Ocean Biosphere: 1997 to 2006

What is productivity? It is photosynthesis. Sometimes referred to as primary productivity. In its simplest form, focusing on the carbon: CO 2 + H 2 O  CH 2 O + O 2 Carbon dioxideWaterCarbohydrateOxygen

CO 2 + H 2 O  CH 2 O + O 2 Photosynthesis   Respiration (light) And it’s really part of a larger carbon cycle. Chemical (oxidative) energy

However, it’s a little more complicated than that, because in order to live and grow (form proteins, chlorophyll, ATP, etc.) a plant actually needs: If any of these inputs is missing, photosynthesis is ‘limited’. Carbon dioxide Light nutrients (N, P, trace elements) ‘Plant’ Biomass (CNP) Oxygen water which produces and gives off inputs outputs

On land growth of plants can be limited by nutrients, light or water. But in the ocean growth of ‘plants’ is limited only by nutrients or light.

Surface Water Phosphate Concentrations NOAA-NESDIS-National Oceanographic Data Center- Climatology

Surface Water Temperature (SST)

Vertical Structure of the Open Ocean Temperature (°C) Depth (m) Surface water: a well mixed layer; single temperature; warm and buoyant The thermocline: depth of most rapid temperature change; boundary between surface and deep water Deep Water: large homogeneous body of water; cold and dense also the photic zone Low and Midlatitude surface water is generally well stratified

13° N N Atlantic Temperature (°C) Depth (m) Depth (m) Nitrate (  mol/Kg) N Atlantic 13° N Low latitude surface water is stratified High latitude surface water is mixed Low latitude surface water is nutrient-poor High latitude surface water is nutrient-rich NABE # ; Sta 5; cast 1; EQPAC; Sta 0; 13.2° N, 142° E

Where does photosynthesis not occur in the ocean? At the center of oceanic gyres: Deep mixed layers and thermoclines, low winds, net downward water flux The oceanic gyres are the ‘deserts’ of the ocean

Where does photosynthesis occur in the ocean? Open ocean; high latitudes: seasonally active; (poor stratification due to cold air and little sunlight; nutrient-rich), light-limited Open ocean; mid to low latitudes: wind-driven upwelling (coastal, equatorial, monsoonal and sporadic; plenty of sunlight)nutrient-limited Along continental margins: especially near river mouths, (groundwater and river runoff, spring melt and rainy season)

Coastal Upwelling Southern hemisphere, hence Coriolis force pushes water to the left of the surface stress

Equator 5° N 5° S Winds Ekman transport Equatorial Upwelling Map view Cross section (a)

Normal conditions – equatorial Pacific

ENSO (El Nino - Southern Oscillation) conditions

El Niño La Niña Warm water is red; cold water is blue Ocean Surface Temperatures : ENSO cycle

El Niño/Southern Ocean Index (SOI) )

Idealized ENSO wave For animation of most recent anomaly asee Animations on the web

Atmospheric Circulation: ENSO cycle

Weather Variation: ENSO cycle winter summer

Return to Productivity:Examples Open ocean; high latitudes: North Atlantic and Pacific, Southern Ocean (polar fronts, convergent and divergent zones) Open ocean; low latitudes: Equatorial Pacific, Indian Ocean (Arabian Sea), Coastal Upwelling: Peru, Namibia & NW Africa Near River Mouths: Congo, Amazon, Mississippi of where there are high rates of photosynthesis in surface ocean water:

NASA/Goddard Space Flight Center, The SeaWiFS Project and GeoEye, Scientific Visualization Studio SeaWiFS Ocean Biosphere: 1997 to 2006

NASA/Goddard Space Flight Center, The SeaWiFS Project and GeoEye, Scientific Visualization Studio SeaWiFS Biosphere: 3 years

NASA/Goddard Space Flight Center, The SeaWiFS Project and GeoEye, Scientific Visualization Studio SeaWiFS Biosphere

Where does photosynthesis occur in the ocean? Open ocean; high latitudes: seasonally active; (poor stratification due to cold air and little sunlight; nutrient-rich), light-limited Open ocean; mid to low latitudes: wind-driven upwelling (coastal, equatorial, monsoonal and sporadic; plenty of sunlight)nutrient-limited Along continental margins: especially near river mouths, (groundwater and river runoff, spring melt and rainy season)

NASA/Goddard Space Flight Center, The SeaWiFS Project and GeoEye, Scientific Visualization Studio SeaWiFS Biosphere: North Atlantic

NASA/Goddard Space Flight Center, The SeaWiFS Project and GeoEye, Scientific Visualization Studio SeaWiFS Biosphere: Amazon River

NASA/Goddard Space Flight Center, The SeaWiFS Project and GeoEye, Scientific Visualization Studio SeaWiFS Biosphere: Congo River & Namibia