Well we’re about 4 hours into day 6, and I can’t believe that this cruise is almost in the books. Don’t get me wrong, we’ve got a lot of science left to do, but despite the challenges we’ve had an immensely successful cruise so far. We’ve got four principal investigators, two grad students, and four technicians, and we’ve worked together like a well oiled machine. I think all of us have learned something about what the others are doing, and I for one am excited for the next cruise in August. But we’re getting ahead of ourselves; what have we learned?
As we expected, the low oxygen water was more prevalent further north – lowest just south of the Bay Bridge, and nearly non-existent by the time we got to Rappahannock Shoals. Our station at the southern end of the region (near the mouth of the Rappahannock), which had higher oxygen concentrations than the northern station (near the mouth of the Choptank), showed some expected patterns of zooplankton vertical distribution – animals were deeper during the day than they were at night. Unfortunately we haven’t seen may jellyfish – I say unfortunately because one of our PIs specializes in jellyfish and they are a seriously understudied component of the ecosystem (in my humble opinion). However, if you plan to swim in the bay this weekend, you might not find this information as unfortunate exactly. We’ve seen some fish eggs and larvae too (as expected), but until we have a chance to really look at the samples it’s hard to say too much about them. We’re still working at the northern station so it’s hard to say much about it, except that we definitely have lower oxygen here than at the southern station.
We’re between operations, but the good new is that we’ve gotten our MOCNESS up and running, thanks to the kindness of some fellow scientists – including the founder of the company that makes them and the current owners. This greatly increases our capacity for sampling plankton. It is an electronically controlled net system that simultaneously takes hydrographic measurements, including salinity, temperature, fluorescence, turbidity, and light, while sampling specific depths with plankton nets. It’s based on an earlier design called the Tucker Trawl and generally works fantastically. We had some problems early on that were probably related to both wear and tear (this system has seen a lot of plankton tows) and operator error, but we’re back up and running.
Our respite is almost over. I’m going to rummage around in the galley for something sweet, then get ready to get back out on deck for another round of plankton sampling…