Marine Food Chains/Webs
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Marine Food Chains/Webs
• Energy from primary production
is transferred up the trophic
chain
• Each step is inefficient (~90% energy is lost)
• Shorter chains are more
efficient at producing apex
predators
Bottom Up Control on the Marine Food
Webs
Primary Secondary Production Production
Phytoplankton
h
CO2 O2
PlantsNUTS FoodWeb
Marine Food Chains/Webs
• Energy from primary production
is transferred up the trophic
chain
• Each step is inefficient (~90% energy is lost)
• Shorter chains are more
efficient at producing apex
predators
Marine Food Chains/Webs
• Open ocean = 90% area & most of
the NPP but little fish
production
• Coastal ocean = 9.9% area & 20%
of the global NPP but ½ of the
fish production
• Upwelling systems = 0.1% area &
little NPP but ½ fish
production
The Upwelling Conveyor Belt
Highest NUTS
High NUTSLow NUTS
High Chl Low ChlLower Chl
High Zoo Low ZooLower Zoo
Sinking POM
The Upwelling Conveyor Belt
Highest NUTS
High NUTSLow NUTS
High Chl Low ChlLower Chl
High Zoo Low ZooLower Zoo
Sinking POM
The 1977 Regime Shift
McGowan et al, 1998: Climate-Ocean Variability and Ecosystem Response in the Northeast Pacific, Science