Wingard, C. E. Oregon State University, cwingard@oce.orst.edu
Cowles, T. E. Oregon State University, tjc@oce.orst.ecu

 
THIN LAYERS: INTERACTIONS BETWEEN INTERNAL WAVES AND PLANKTONIC DISTRIBUTIONS ON SCALES OF CENTIMETERS TO METERS
 
The accumulating evidence for persistent, small-scale biological structure raises questions about the range, frequency and intensity of physical/biological interactions in the ocean. These features force us to evaluate the contribution of specific physical mechanisms (i.e., stratification, vertical shear, internal waves and mixing) in the formation, maintenance and erasure of these features. We addressed the influence of internal waves on small-scale biological structure by deploying a thermistor chain during cruises off the Oregon coast in September 1997 and 1998 for periods of 36-72h. Thermistors spanned 50m of the water column with 3m vertical resolution and 5s temporal resolution. We obtained time series of high-resolution (2-5cm) profiles of physical and bio-optical properties with a free-fall instrument package during thermistor chain deployments. These high-resolution profiles were contrasted with coarser-scale profiles obtained with a conventional CTD system. <P> We observed internal wave displacements of small-scale planktonic structure across a frequency range from 0.1cph to 10cph. We saw 10m vertical displacements as non-linear wave packets (solitons) moved past the vessel. Specific vertical displacements were correlated with temporal changes in small-scale bio-optical and physical properties. We present an analysis of these data in the context of persistence and erasure of small-scale structure.
 
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
 
Code: SS05TU0183S