(Gu and Smith, 1997) and marine mixed layer (Sathyendranath and Platt, 1988)
biogeochemistry. Similarly, models of the diel light regime on reefs can be used to
force benthic community photosynthesis versus irradiance functions developed by
measuring metabolism of defined biotopes under conditions of diurnally or seasonally
varying illumination (Larkum, 1983). Morel (1988) and numerous other researchers
have developed optical models for Case 1 waters that are typical of the tropical oceans
adjacent to reef systems, defined as those waters for which phytoplankton and their
derivatives predominate in determining optical properties. These pigment-dependent
optical models allow the propagation of sunlight in the upper ocean to be predicted as a
function of the local algal content, a variable that in turn may be estimated from
satellite observations of ocean spectral reflectance, informally called “ocean color”
(McClain et al., 2004).
Sathyendranath and Platt (1993) presented a general approach to the estimation of
integrated ocean primary production that could readily be adapted to the modeling of
benthic gross photosynthesis across reef systems. This approach is based on combining
satellite ocean color sensing of global mixed layer algal biomass with spectral models
for the computation of ocean surface and interior irradiance, and local photosynthesis/
irradiance algorithms (Sathyendranath and Platt, 1993). Clearly, the benthic light
regime driving gross photosynthesis on coral reefs can be obtained by combining
models of atmospheric and submarine light transmission with synoptic multi-temporal
information on atmospheric and sea water opacity from multiple source satellite
observations. A complicating factor in this application is the need to remove the
component of upwelling radiance that is derived from refection at the sea floor from the
total spectral water-leaving radiance that is observed by ocean color sensors following
atmospheric correction. Given knowledge of the spatial pattern of bottom albedo on
reef systems from high resolution mapping sensors or in situ measurements, we regard
this task as tractable.
The structure and function of coral reef communities reveal geographic differences
that appear to be greatly impacted by nutrient inputs (Birkeland, 1988). Further, there
is evidence that reef algae, animals with zooxanthellae, and coral reef communities
show nutrient-limited responses for gross photosynthesis and net primary production
(Atkinson, 1988). Apparently, aspects of the community productivity of coral reefs can
be nutrient-limited (Atkinson, 1981; Atkinson, 1988), but the conception of nutrient
limitation by a single nutrient is an oversimplification for reef systems (Lewis et al.,
1985).
Hydrodynamics are important in the nutrient-regulation of coral reef communities
because N versus P limitation of the net production of aquatic ecosystems is largely a
function of the degree of confinement (Smith, 1984). Remote sensing can aid
hydrodynamic studies that are aimed at determining nutrient-regulation across reef
systems by setting the initial boundary conditions for simulations of circulation, in flow
model validation, and in the calibration of particle transport models (Acker et al., 2004;
Gibbs and Shaw, 2002; Ouillon et al., 2004; Young et al., 1994). Sea surface
temperature (SST) fields derived from Advanced Very High Resolution Radiometer
(AVHRR) observations acquired by NOAA polar orbiting satellites (Li et al., 2001) are
commonly used to establish surface boundary conditions for regional hydrodynamic
circulation models. Normally, these satellite thermal infrared images are used to
determine initial SST conditions, and then additional satellite SST fields are assimilated
during the simulation of circulation to calibrate or validate the model. For example,
Gibbs and Shaw (2002) presented a methodology for the use of remotely sensed SST
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biogeochemistry. Similarly, models of the diel light regime on reefs can be used to
force benthic community photosynthesis versus irradiance functions developed by
measuring metabolism of defined biotopes under conditions of diurnally or seasonally
varying illumination (Larkum, 1983). Morel (1988) and numerous other researchers
have developed optical models for Case 1 waters that are typical of the tropical oceans
adjacent to reef systems, defined as those waters for which phytoplankton and their
derivatives predominate in determining optical properties. These pigment-dependent
optical models allow the propagation of sunlight in the upper ocean to be predicted as a
function of the local algal content, a variable that in turn may be estimated from
satellite observations of ocean spectral reflectance, informally called “ocean color”
(McClain et al., 2004).
Sathyendranath and Platt (1993) presented a general approach to the estimation of
integrated ocean primary production that could readily be adapted to the modeling of
benthic gross photosynthesis across reef systems. This approach is based on combining
satellite ocean color sensing of global mixed layer algal biomass with spectral models
for the computation of ocean surface and interior irradiance, and local photosynthesis/
irradiance algorithms (Sathyendranath and Platt, 1993). Clearly, the benthic light
regime driving gross photosynthesis on coral reefs can be obtained by combining
models of atmospheric and submarine light transmission with synoptic multi-temporal
information on atmospheric and sea water opacity from multiple source satellite
observations. A complicating factor in this application is the need to remove the
component of upwelling radiance that is derived from refection at the sea floor from the
total spectral water-leaving radiance that is observed by ocean color sensors following
atmospheric correction. Given knowledge of the spatial pattern of bottom albedo on
reef systems from high resolution mapping sensors or in situ measurements, we regard
this task as tractable.
The structure and function of coral reef communities reveal geographic differences
that appear to be greatly impacted by nutrient inputs (Birkeland, 1988). Further, there
is evidence that reef algae, animals with zooxanthellae, and coral reef communities
show nutrient-limited responses for gross photosynthesis and net primary production
(Atkinson, 1988). Apparently, aspects of the community productivity of coral reefs can
be nutrient-limited (Atkinson, 1981; Atkinson, 1988), but the conception of nutrient
limitation by a single nutrient is an oversimplification for reef systems (Lewis et al.,
1985).
Hydrodynamics are important in the nutrient-regulation of coral reef communities
because N versus P limitation of the net production of aquatic ecosystems is largely a
function of the degree of confinement (Smith, 1984). Remote sensing can aid
hydrodynamic studies that are aimed at determining nutrient-regulation across reef
systems by setting the initial boundary conditions for simulations of circulation, in flow
model validation, and in the calibration of particle transport models (Acker et al., 2004;
Gibbs and Shaw, 2002; Ouillon et al., 2004; Young et al., 1994). Sea surface
temperature (SST) fields derived from Advanced Very High Resolution Radiometer
(AVHRR) observations acquired by NOAA polar orbiting satellites (Li et al., 2001) are
commonly used to establish surface boundary conditions for regional hydrodynamic
circulation models. Normally, these satellite thermal infrared images are used to
determine initial SST conditions, and then additional satellite SST fields are assimilated
during the simulation of circulation to calibrate or validate the model. For example,
Gibbs and Shaw (2002) presented a methodology for the use of remotely sensed SST
120
Brock, Yates and Halley