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Notes on Shedding light on the ocean’s biological pump and twilight zone processes, a presentation given by K. Buesseler (07/17/09)

Biological pump

  • Why it is important:
    • Impact on global carbon (C) cycle and climate
    • Rapid, yet inefficient transport
    • Food sources for ecosystems
  • Variability of particulate organic carbon (POC):
    • Flux poorly understood even after 20 years
    • Even seasonal variability is hard to see
  • Layered structure of chlorophyll: constant over the upper 60 m, shifted to constant and near zero below
  • Definition of twilight zone: below the euphotic zone down to 1000 m

Shedding light

  • Parameterize the vertical profile of POC flux:
    • Avoid the Martin curve
    • Need new metrics to compare biological pump
    • Synthesis is dependent on the metrics used
    • So far, no perfect metrics found
  • New models with a minimum set of biological processes are needed:
    • Simple 1-D layered biological model containing (see Buesseler and Boyd, 2009) containing microbial solubilization, zooplantkon remineralization and vertical migration of zooplankton