The basic bio-optical application for the tower system will be to relate physical processes on the mid-to-outer shelf to surface and subsurface variability in bio-optical properties, notably chlorophyll, CDOM fluorescence and absorption, and attenuation coefficients. Physical processes which will strongly influence bio-optical property distributions include variability in cross-shelf hydrographic structure and exchange, Gulf-Stream eddies, and resuspension of fine particles by major storms. While a regional scale, synoptic picture can be obtained from satellite imagery, this is patchy in time and space due to variable cloud cover, and is limited to the bio-optical signal coming from the upper water column only. The tower network will provide information on physical and bio-optical properties on a continuous basis, with depth resolution. Once developed, the tower system will also offer a potentially valuable site for field testing a range of bio-optical instrumentation and calibrating and validating bio-optical products and models
With the exception of the turbid coastal zone, much of the South Atlantic Bight shelf sea is often in the euphotic zone and benthic macroalgal production contributes significantly to total mid-shelf primary production. From continuous above- and in-water measurements of visible irradiance (Photosynthetically available radiation, or PAR) at R2 and M2, intergrated daily irradiance and attenuation in the water column are determined (see figure below).
At R2 daily PAR flux to the bottom varies with daylength, cloud cover and optical variability in the water column. Higher turbidity in winter may be associated with the transport of coastal water across the Georgia shelf and resuspension of fine material from the sand sediments of the mid-shelf during storms.