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Intro to Ocean III- open ocean

http://syque.com/ds/pix/maldives_07/ocean_light_800.jpg

Surface ocean, photic zone

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ocean productivity, why do we care?

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variability in ocean primary productivity

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We must consider: 1) spatial variability across oceans surface (e.g. nearshore to open ocean)

2) patterns with depth

spatially variability in ocean productivity

5geoserver.isciences.com

Connection between surface and deep water

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Biological Pump- Sinking material (feces, phytoplankton, fish, etc) causes the transport of organic matter from photic zone to deep ocean

This can reduce nutrient concentrations at surface

Organic material transported from surface waters to deep waters causes the release of nutrients in deep ocean

www.sciencedaily.com

What controls ocean productivity?

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• Nutrient levels- From coastal runoff- From deep water nutrient sources (upwelling)- From nitrogen fixation

• Temperature

• Light level

• Phytoplankton composition and grazing

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• UNEVEN HEATING FROM THE SUN (uneven delivery of solar radiation from sun)

• Uneven Density and Pressure differences–Based on temperature and moisture

variations• Rotation of the Earth Coriolis Effect

(Wind to deflected to right in North, deflected left in South)

• Surface topography (Earth landforms)

•What controls atmospheric circulation?

Controls on ocean productivity

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Ekman transport- persistent winds and the coriolis effect cause the bulk movement of water in the northern hemisphere to be 90 degrees to the right of wind direction

Controls on ocean productivity

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Upwelling- The offshore movement of water, due to Ekman transport, will cause surface water to be replaced by deep water (cold, nutrient rich)

Nutrients transported to surface waters by upwelling causes increased productivity

Controls on ocean productivity

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Upwelling- The offshore movement of water, due to Ekman transport, will cause surface water to be replaced by deep water (cold, nutrient rich)

Cool waters along the NJ coast due to upwelling…

Which direction would the wind blow along the coast in order to cause this upwelling?

Aphotic zone- deep sea

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Where does energy come from in the aphotic zone?

13http://www.pmel.noaa.gov/vents/geology/images/Seafloor_spreading.jpg

14http://www.pmel.noaa.gov/vents/geology/images/Seafloor_spreading.jpg

Hydrothermal vents

15www.whoi.edu

Hydrothermal vents

16www.whoi.edu

Chemosynthesis

vs

Photosynthesis…

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Hydrothermal vents

18www.whoi.edu

Hydrothermal vents

19www.whoi.edu

• IMAX video clip on deep sea and hydrothermal vents

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