Post on 23-Feb-2016
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Open Oceans: Pelagic Ecosystems III
Comparing the makeup of water and plankton
• Mean Elemental Ratios of N, and P• Organisms: 16.0N / 1P• Sea Water: 14.7N / 1P
• On average, seawater lacks sufficient organic N to take advantage of the available phosphorus
Limited water mixing further limits nutrient availability
Testing models: measuring plankton in open oceans
• Techniques for studying plankton consumers
• Plankton levels may be dropping (NASA study)
From productivity to food webs: A size-based pelagic food web
Grazing pressure
Limits & Flows of NPP
Marine “Snow”
krill
A spatially realistic pelagic food web
What are links among trophic levels in pelagic systems?
Large phytoplankton vary with depth
Nutrient distribution with depth
Distribution of food web biomass
The global nitrogen cycle
Influences on biologically useful Nitrogen
Diatom mats can migrate vertically
Consequences of active transport of NO3
Links to oceanic nekton