Relationship Between Physical and Biological Properties on the Microscale: A Cross-Comparison Between Differing Coastal Domains

Attenuation of light and sound propagation in the upper ocean is tightly linked to the patterns of vertical distribution of particulate matter (primarily detritus, phytoplankton, and zooplankton). Local maxima in these distributions frequently occur within the euphotic zone, and are often concentrated within depth intervals that are less than 1-2m thick (e.g., Dekshenieks et al. 2001, Cowles 2004). Of particular interest are the steep vertical gradients of stratification and/or shear that often exist at the boundaries of these thin plankton layers, and which are implicated in their formation and maintenance (e.g., Stacey et al. 2007, Birch et al. 2008). We are extending the analysis of thin plankton layers by examining the microstructure datasets obtained over the past decade by the Ocean Mixing Group at Oregon State University. Tens of thousands of profiles have been obtained over the central Oregon shelf (COAST), over the New Jersey shelf (SW06), and around and through the buoyant Columbia River plume (RISE). Plots of cross-shelf property distributions have revealed extensive layers of