Wecoma Cruise Report Aug 6-8

The R/V Wecoma sailed at 1300 on 6 August to conduct the second COAST survey cruise. We transited north to the inshore end of line 1 off Cape Kiwanda. Along the way we checked the inshore ends of our SeaSoar sampling lines and were pleased to see less crab pot gear than in May/June. The commercial crab season ends on 15 August so we're hoping to have even fewer pots to dodge in a week or so. Another beautiful evening off Cape Kiwanda as we deployed SeaSoar, the HTI bio-acoustics sled and the iron pumped sampler. Zanna Chase and Roseanne Schwartz are collecting discrete samples for iron which they'll analyze later after their repaired spectrometer is returned within a day or two. Surface nutrients are up and running from the start of SeaSoar sampling.

We have been towing south on the Big Box grid and have completed lines 1-6. We expect to finish the grid on the inshore end of line 8 near Reedsport around midnite tonite (8 Aug). We will then tow SeaSoar/HTI/Fe north along the 50 fm (91.4 m) back to the vicinity of the Cascade Head line (line 2) where we'll SeaSoar around the Thompson. At dusk on Thursday, we plan to begin a CTD and zooplankton net section along the Cascade Head line.

Surface temperatures were high (> 13.5 degC) early in the survey, but we can clearly see the upwelling of isolines (T, S, sigmat) as the northerly wind remains around 20+ knots. The upwelling front and jet is close to shore in the north, then moves offshore to pass over the top of Stonewall and the northern peak of Heceta Bank. The upwelling jet on line 2 was about 20 cm/s centered around 124.24W (140 m isobath). On our last sampled line (line 6) the jet was over 30 cm/s centered at 124.6W. Inshore on line 6 (Cape Perpetua) there is a second, newly formed upwelling front. We can trace dense water (> 26.5 kg/m**3) all the way from line 1 to line 6, the latter line having dense water in a thick (50m) layer next to the bottom. Surface chlorophyll increases in magnitude and spreads out more from the coast as we sample southward. Along the Cape Perpetua line (line 6) we see a huge subsurface chl max between 10-20m centered at 124.5 W. Tim Cowles says he hasn't seen the FlashPak fluorometers aboard SeaSoar give 4+ volts before and estimates the chl values as 20-25+ mg/m**3. We'll pin that down with the surface chlorophyll extractions made by Tim's group.

All is well on Wecoma and scientists and crew are up and running at top efficiency despite the lumpy seas.

Submitted 1130 on 8 Aug 2001 by Jack Barth, ChSci Wecoma