On Thursday night (Feb. 9) the Delaware II is in the Northeast Channel doing a Niskin bottle rosette cast after an initial bongo net tow. Weather conditions are very good, as they have been since we left Portland Harbor on Tuesday evening. This improvement in sea conditions has allowed us to make rapid progress eastward across the northern part of the Gulf of Maine, continuing with our plankton sampling and hydrography. One equipment problem that has plagued us during this time was an electronic glitch that interfered with some of the rosette water sampling casts, but that was resolved this afternoon by our electronics technician (ET) who tracked the problem to a small nick in a deck cable that ran to the winch from the dry lab.
This allowed enough seawater to enter where it would interfere with rosette casts, which send power down the cable to trip the water bottles, but it didn’t affect bongo operations that only receive small electronic signals up from the CTD unit on the wire. It was very perplexing but is now thankfully resolved as I can attest to by our current rosette cast which is going well.
The only other problem on the horizon is weather again. Conditions are forecast to change rapidly this weekend, and so we find ourselves in a race against time to work our way back west across the southern Gulf of Maine. The “prize” will be the ability to continue working, both with our bongos and rosette water sampler, all the way across until we reach the sheltered inshore waters near Cape Cod. To lose the race will mean being stuck offshore in the Gulf of Maine, unable to work and having to “jog” eastward at three or four knots into rapidly increasing seas for hours to reach the Cape. Based on where we are at the moment, in the Northeast Channel at 9:30 Thursday night, I think we’ll be able to visit most of our remaining Gulf of Maine stations and even one on the northern edge of Georges Bank and be safely across in time.
Plankton catches have continued to be light, with a distinct shift to more Calanus copepods with euphausiids and some decapod shrimp showing up in the night tows. We’ve also had a few comb jellies (Pleurobranchia) in some of the tows. No fish larvae have been seen since our Georges Bank sampling.
I’d like to thank our ET, Ed Morse, who gave up a lot of sleep to track down and fix our rosette problem, the command who have been constantly “tweaking” our cruise track to make the most of this break we’ve had in the weather, and the crew for patiently routing and re-routing our wiring and gear out on the cold deck until our rosette problems were resolved.
Winter Ecosystem Monitoring Survey