The Epipelagic
• The pelagic realm of the ocean describes the vast, open ocean.
– The epipelagic realm is the upper part of this environment.
• Depths only to about 200m• Corresponds to the depth of the euphotic
zone– Euphotic depth the depth below which where there is
no longer enough light for organisms to grow.
– Divided into coastal, or neritic waters that lie over the continental shelf, and oceanic waters.
Net Tows
Plankton by Size
• Plankton: organisms that can’t swim against a current– Picoplankton (0.2 – 2 m) and Nanoplankton (2 –
20m)» Mostly bacteria and very small single celled algae
– Netplankton (>20m)» Includes the larger phytoplankton and all of the
zooplankton
Plankton by Size
Phytoplankton
– Responsible for >95% of the photosynthesis in the oceans and over ½ the primary production on earth
• Most important members are diatoms and dinoflagellates.
• Cyanobacteria are also important phytoplankton because they are able to fix nitrogen, ie. turn inorganic nitrogen into organic nitrogen that can be used by phytoplankton.
Figure 15.03
Epipelagic Food Web
Copepod
Figure 15.07b
Larvacean
Pteropod
Figure 15.11b
Figure 15.11c
Figure 15.11d
Figure 15.11e
Fish Larva
Chaetognath (Arrow Worm)
Comb Jelly
Polychaete Worm
Copepod
Figure 15.13b
Crab Zoea
Fish Larva
Figure 15.13e
Snail and a Jelly
Nekton
Nekton
Diel Vertical Migration
Neuston
Nekton
Staying Afloat
Camouflage
Epipelagic Food Web
Global Productivity
Figure 15.25b
Figure 15.26
Seasonal Productivity-Tropics
Seasonal Productivity- Temperate
Seasonal Productivity- Polar
Wind-Driven Upwelling
Global Upwelling
Figure 15.32
