Wecoma daily report, 12 August 2001

Scientists aboard Wecoma have completed a CTD and zooplankton net sampling section along the Cape Perpetua line. We sampled from CP-12 to CP-1 from 1900 on 11 August until 1500 on 12 August. After completing only line 1 of our planned second Bigbox survey, the Wecoma's trawl winch failed. This is the winch we are using to tow SeaSoar using a fiber-optic tow cable. The failure necessitated a turn to the south to transit along the 200m isobath while repairs were attempted instead of traveling into shallow water along the Bigbox grid lines. The ship's engineers and MarTechs managed to restore the trawl winch temporarily and we recovered the SeaSoar. Further SeaSoaring is on hold until we can effect repairs in Newport on Tuesday when a winch repairman is available. The Tuesday port call will take the place of our planned Wednesday port call when we will exchange a few personnel.

Since we couldn't SeaSoar, we decided to do CTD/zooplankton/ADCP sampling along the CP line (line 6). Meanwhile, Thompson also sampled along the CP line and we passed near CP-3 with Thompson transiting offshore conducting microstructure and pumped profiling. The line 6 velocity section showed mostly northward flow, with up to 10 cm/s on the inshore end of the line. The only southwest flow (10-15 cm/s) was in the upper 50m between 124.5 and 124.8 W. We completed CTDs and vertical zooplankton net tows at all 12 CP stations and made MOCNESS zooplankton tows at CP-11, CP-8 (both day and night samples), CP-4 and CP-2. At CP-8 the vertical migration of euphausiids was documented and at CP-4 huge numbers of euphausiids and copepods were caught. More details will follow when Bill and Jesse wake up from their rest after a long night of zooplankton work :)

As was found during the previous SeaSoar section along line 6, high chlorophyll fluorescence was found from CP-6 (5+ volts from 8-16m) to the coast. We observed a deep chl max at CP-5 at a depth of 40-50m. At CP-3, there was 3 volts chl fluorescence at 10m and again in a subsurface maximum at 30m. There was even 1 volt chl in the BBL. At CP-2 there was 4+ volts at the surface and 2.5 volts from 35m to the bottom in a BBL. CP-1, the most inshore station had high chl throughout the water column.

Around 1500 on 12 August, we started an ADCP survey along line 7 to the south of the CP line in order to further document the currents in the Heceta Bank region. After sampling along line 7 we headed north to line 3 (Cape Foulweather line) and will conduct a CTD/ADCP section in order to provide the initial hydrographic and velocity fields for the dye release from R/V Elakha planned for late morning on 13 August. On Monday we plan to help with the dye tracking and measurement and to perhaps make some CTD and zooplankton measurements on the NH line. When Elakha departs for Newport around 4pm, we'll continue to track the dye patch and hand it off to Elakha early Tuesday morning before we head into port. We're due in Newport at 0800 on Tuesday and hope the trawl winch repairs go well.

Submitted at 2330 on 12 Aug 2001 by Jack Barth, Chief Scientist, R/V Wecoma