Introduction
Observations of persistent thin layers (20-40cm in thickness) of biological structure have raised many questions about the role of these features in upper ocean trophic dynamics, optical and acoustical signal propagation, and remote sensing. We do not yet understand the mechanisms that lead to the formation and maintenance of small- scale vertical structure in the upper ocean. This project addresses these issues through several specific objectives. First, we wish to define, in coastal environments under a range of forcing conditions, the small-scale structure of planktonic organisms, as identified through measurements of spectral light absorption, attenuation, light scattering, and spectral fluorescence. Those optical measurements have coincident measurements of the small-scale vertical structure in downwelling spectral irradiance, upwelling radiance, temperature, salinity, and density. Second, we wish to quantify the role of physical processes such as internal waves and small-scale vertical shear in horizontal velocity on the persistence of plankton layers. In collaboration with other ONR investigators in the East Sound Thin Layers experiments, we are investigating the interaction between the vertical scales of distribution of dissolved organic compounds (as detected with in situ optical sensors) and those optical properties relevant to remote sensing (absorption and reflectance).
This work has been supported by the Office of Naval Research. We are indebted to Eric Boget, Captain of the R/V Henderson for his assistance during our field operations.
