44
phytoplankton
POM
1
zooplankton
grazing flux
I
fish
1
aggregation/
disaggregation
sinking flux
~
sedimentation
diagenesis
S. Pantoja · S. Wakeham
air-sea exchange
excretion!lysis
~J L.
microbial loop
j
benthic flux!
resuspensation
bioturbation
1
J~
advection
..- ---.
Fig. 2.1. Schematic of biogeochemical cycles in the ocean, showing the grazing food chain, sinking flux,
and microbial loop (adapted from Azam 1998)
2.1.1
Organic Carbon Cycle
Carbon is a fundamental element of life and thus is a key component of all organic
compounds. Hedges and Oades (1997) have presented a recent compilation of the reservoirs and fluxes within the global carbon cycle (Fig. 2.2). Most carbon on earth is
sequestered on geologic time scales in sedimentary rocks, predominately as inorganic
carbonates (60000000 Gt C [Gt = 10 15 g]). About 15 000 000 Gt of organic carbon (DC)
phytoplankton
POM
1
zooplankton
grazing flux
I
fish
1
aggregation/
disaggregation
sinking flux
~
sedimentation
diagenesis
S. Pantoja · S. Wakeham
air-sea exchange
excretion!lysis
~J L.
microbial loop
j
benthic flux!
resuspensation
bioturbation
1
J~
advection
..- ---.
Fig. 2.1. Schematic of biogeochemical cycles in the ocean, showing the grazing food chain, sinking flux,
and microbial loop (adapted from Azam 1998)
2.1.1
Organic Carbon Cycle
Carbon is a fundamental element of life and thus is a key component of all organic
compounds. Hedges and Oades (1997) have presented a recent compilation of the reservoirs and fluxes within the global carbon cycle (Fig. 2.2). Most carbon on earth is
sequestered on geologic time scales in sedimentary rocks, predominately as inorganic
carbonates (60000000 Gt C [Gt = 10 15 g]). About 15 000 000 Gt of organic carbon (DC)