Thompson Report June 1

Thompson Report for May 31 - June 1.(23:00 local time) We are hoping to do three or four cross shelf vertical profiling transects as we head back north. We just completed the first of these along 44 22.5 N out to 124 32.8 W with fixed depth pump stations at each end. At the inshore end, chl fluorescence was about 2 v in the surface in a layer about 20 m thick, the bottom 15 m was also very high in fluorescence and scattering. The inner and middle shelf here has a very thick bottom boundary layer, very high turbulence and a weak northward flow. A subsurface chl maximum develops offshore, just as we cross the inner edge of the Columbia River plume there was a region of high turbulence which brought cooler water and presumably more nutrients to the surface. The profiling transects show lots of horizontal layering and along this line both bottom mixing and increased turbulence in some parts of the water column. I will ask Sasha to post an image when he can (they have had some problems with software so it may not be ready tonight).

All systems are working well, but the filtering teams are getting quite a workout with this schedule. We are headed for line over Stonewall Bank 44 32.4 N. Jim wants to occupy this line because of his past studies here, and we would like to see the effect of the bank on the vertical distribution of nutrients. Our ETA for the inshore station is midnight (Thursday) and after a 1 h pump station, we will start the profiling transect which should take 10-12 h, and then do a 2 h pump station at the outer end. If all goes well we will then move on to the NH line.

Pat