Yesterday the Three Seas Marine Ecology class went on an Oceanographic Cruise!! As the teaching assistant for the course, I got to accompany the students on the cruise. This field trip is designed to get students acquainted with common tools used by oceanographers on research vessels.
It was still dark at 6am when we all piled into the big red Northeastern vans and hit the road headed for New Hampshire. While the students slumbered quietly in the back of the van, I glimpsed some sunrise views that were quite picturesque, even if they were from the highway. We arrived in Portsmouth where we met our generous hosts, researchers from University of New Hampshire who were kind enough to take us out on their research vessel, The Gulf Challenger. It was quite chilly at first (as you would expect out on the water at 8am), but we came prepared with our foul-weather gear.
Our first stop was right in the harbor where we tested out some cool equipment. First we used a grab sampler to check the composition of the ocean floor beneath us, an essential step before taking a core sample. If the grab sampler came back empty, then we would assume it was solid rock below us, and therefore not a great place to take a core sample (unless our goal was to break the corer). Lucky for us though, our grab sample came back with soft and delicious looking mud – perfect for core sampling! We watched as our fabulous guide, Deb, positioned the corer and the boat captain released the winch and sent it harpooning towards the bottom.
Once the corer was retrieved, we were ready for the fun part, sifting through all the mud and sand to find infaunal invertebrates! We found lots of worms, and Deb explained the layers of mud and sand in the core, including a layer of clay-like glacial till called “presumpscot” (its fun to say, try it!)
After cleaning up the mess we made sorting through the presumpscot, we got down to business, collecting a slew of oceanographic data using a high-tech instrument called the CTD. This acronym stands for some of the measurements the device can take: Conductivity (fancy term for salinity), Temperature and Depth. In addition to these, the CTD can also measure oxygen concentration, light intensity and fluorescence of sea water. Our goal was to take measurements at several locations on our 3 hour cruise from the open ocean up the Piscataqua River, which forms the border between New Hampshire and Maine. We deployed the CTD in the open ocean, at the mouth of the river and then a couple miles up the river, in order to see how the water conditions change at the border between a marine and estuarine habitat. The CTD takes measurements every fraction of a second, so as we lower it to the ocean floor and raise it back up to the boat, it is constantly taking measurements, allowing us to also examine how water conditions change with depth.
As the cruise continued and the sun rose in the sky, we shed our layers, basking in the rays of the beautiful fall day. It was one of those moments when we all realized that, despite sacrifices like waking up in the dark, studying marine biology isn’t all that bad.