SEA Currents: Robert C. Seamans
March 20, 2017
The People’s Net
43°23.2’S x 173°33.2’E
Ship’s Heading & Speed
140° at 2.3 knots
Force 2 winds with clear skies. Five foot seas approaching from the Northeast.
Mattias, the Chief Scientist, and I were sitting in lab the other day idly chatting and, after a lull in the conversation, Mattias turns to me and asks what I think the theme song for the Neuston should be. With some thought and discussion, we decided it should be some kind of power ballad from the 80s. Perhaps Styx’s “Come Sail Away” or Journey or something like that. The reasoning for this is the Neuston is a workhorse, unassuming yet always gets your toe tapping; oddly shaped yet user friendly. It’s probably my favorite net because it just shows up and gets the job done.
At the time of writing, we’ve deployed 36 Neuston tows over the past six weeks and it is the most familiar of deployments for all onboard. The Neuston net is deployed twice a day around noon and midnight and is towed along the surface of the ocean for a half hour with the ship going two knots. The net samples the air and sea interface, the Neuston layer, and is one meter wide by half a meter tall. The small 333 micron mesh catches all sorts of zooplankton and nekton. Most notably on this trip, we’ve caught myctophids, phyllosoma (spiny lobster larvae), squid, Janthina bubble raft snails, Portuguese Man O wars, megalopae, numerous species of amphipods and copepods, and surprisingly three seahorses. Our largest tow consisted of 1,509 salps that filled a large Tupperware bin and required the strength of four people to pull in the net (see photo). Honestly, it doesn’t get much cooler than seeing the Neuston gliding through the evening seas glowing with bioluminescence. Add in bioluminescent dolphins swimming by and a clear starry night above and it makes for an amazing moment.
In addition to Neuston tows, we have deployed 44 surface stations, 28 phytoplankton nets, 13 hydrocasts, 11 secchi disks, three meter nets, and one styrocast. All of these deployments have been used to gain a deeper understanding of New Zealand’s waters and to help bring answers to research questions asked by the students.
Onshore eleven of the students developed their research questions with the help of Mattias and Teaching Assistant/2nd Assistant Scientist Nick and came aboard with a research plan in hand. Topics include ocean acidification and the spatial distribution of CO2 (Maddy and Madeline), geostrophic current structure along the eastern continental margin of NZ (Jen), the effect of pH on pteropod distribution (Rose and Kristina), the effect of nutrient ratios on phytoplankton community composition (Kate P. and Kai), the correlation between phytoplankton, nutrients, temperature, and the deep chlorophyll maximum (Sophie V. and Austin) and myctophid diet and distribution (Shem and Lydia).
The lab is a 24 hour operation where we spend roughly five hours a day actively deploying the scientific equipment and the rest of the time is spent processing the samples collected, cleaning up after the last deployment and prepping for the next. While only eleven of the 26 students are in Directed Oceanographic Research, all students are expected to cycle through lab and be involved in the scientific mission. It is a ship wide collaboration.
With the trip wrapping up, we’ve run the last of our nutrient analyses today and the students are busy writing their final reports. Even as our sampling plan has been cut back, we are still deploying the Neuston on the daily. There is always something to learn and explore and the Neuston can be trusted to deliver.