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Sergio Hoare / WCS

Note on the absence of nutrient data in indicators of water quality:

We have not been able to locate any long-term (> 2 years) routine (weekly) monitoring data for nitrogen and

phosphorous within the region. Quite possibly some exists but we have not been able to access it. Numerous

one-time surveys have occurred, but without routine time series capturing the full range of seasonal and climatic

variability these data do not give enough information to interpret the status of nutrients. Nutrient levels would

need to be evaluated on a site-specific basis as deviations from norms (standard values for each parameter) over

the full range of seasonal variation. Even if frequent, consistent data were to be collected, there are the additional

problems associated with the sensitivity of the instruments needed to take accurate measurements in waters

with relatively low nutrient concentrations (compared to other marine ecosystems) and with the rapid biological

uptake of these nutrients into phytoplankton. Once the nutrients are taken up by phytoplankton, or even cycled

into zooplankton, they are no longer in the dissolved inorganic form (and thus not measurable as such). However,

there are important changes in trophic dynamics (favoring filter feeders like sponges versus autotrophic feeders

like corals) that result from changes in plankton concentrations fueled by nutrient enrichment. Thus, it is the

measurement of the associated decrease in water clarity or transparency (S8) and chlorophyll pigment within

phytoplankton as seen from satellite remote sensing as "ocean color" (S9) that we suggest can be more feasibly

and accurately measured over the long term on the scale of the MAR, and can serve, in some regard, as a proxy

for nutrient concentrations.

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