and we’re off
Day 3 | Sunday June 18, 2023
Our research cruise has officially begun! We left the Port of Nome at around 10 AM on Friday June 16th, conducted our first ‘test’ science stations through a transect along the Bering Strait, and are currently ~halfway through our 36-hour steam up north into the Chukchi Sea for our first official sampling sites.
We got incredibly lucky with the weather on our first day. One of the crew claimed that it’s the calmest he’s ever seen the Bering Sea. The sun was shining, the water glassy, and the boat rode along so smoothly it felt almost as if we were still on land. I was sitting in my stateroom (aka bedroom) remarking on how calm the ride seemed when I heard what sounded like someone dragging a heavy bag along the side of the deck below me. It took me a bit longer than I’d like to admit to realize what was actually going on – we were scraping along sea ice. We hadn’t expected to hit sea ice until we got much further North, but I guess the weather has been cold enough to keep the sea ice frozen and floating along the Bering Strait. What started as little chunks scattered around soon surrounded us. We were immersed within the ice for hours, slowly making our way through.
Classified as an icebreaker vessel, the R/V Sikuliaq is capable of making it’s way through sea ice up to a meter thick. However, in an effort to save fuel and maintain safety, the crew tries to find as clear as a path as possible, weaving us between the large ice floes (floe is the term for a floating piece of ice … a word recently added to my vocabulary as well). This means the journey is relatively slow going, as we travel at the lazy speed of 2–4 knots when surrounded by sea ice (a knot is a nautical mile per hour & one knot is roughly equal to 1.15 mph). So there was plenty of time once we left the Port of Nome to prepare the lab spaces, get trained on the science protocols, have a very important safety briefing from the captain, and practice drills in case of fire, abandon ship & man overboard scenarios.
Our first science stations were within the Bering Strait (yes the same Bering Strait that we learned about in middle school social studies that was home to the land bridge connecting Asia to the Americas). These stations are not a part of our primary data collection, however they were a great opportunity to practice the timing of everything, test out equipment and just generally get a feel for how a science shift will work. We started at the eastern edge of the Strait (up along the coast of Alaska) and moved our way west, in an almost horizontal line. We conducted a total of 8 stations, each one included a CTD deployment and a variation of other measurements as well. Throughout this blog I’ll explain each of the measurements/projects being conducted on this cruise in much more depth don’t worry, but for now I’ll just focus on the CTD.
CTD stands for conductivity, temperature, depth and actually refers to the little set of computers housed at the very bottom of this contraption. Conductivity is used to measure the salinity of the water and there is also a PAR sensor attached that measures light levels – these values along with the water temperature and depth are live-streamed back to the vessel throughout the entire deployment of the CTD. Although most commonly referred to as a CTD, this entire piece of equipment is actually called a rosette and it holds the CTD, PAR sensor as well as 24 bottles (called niskin bottles) that collect water samples. As the CTD is lowered, members of the science team are watching the livestream of data and determining which depths they want to collect water from – typically the bottom (~50 meters) and surface (~ 2 meters) are consistently collected from. In the case of this cruise, we also collect from the deep chlorophyll maximum layer (which is the point where phytoplankton & primary production are typically the highest, and varies based on light and other water conditions at each sample point).
Once the CTD has reached its lowest depth, we then program it to shut the niskin bottles at our identified depths and it slowly rises back up through the water column – triggering the closure of a couple bottles at each depth. By the time it’s back in the Baltic Room, the CTD is completely full of water, with the bottles containing water from different points in the vertical water column. This water is collected and measured for many things – chlorophyll & nutrient concentrations, phytoplankton abundance (and more that I’ll explain later) and then we’re ready to move forward and do it all again at the next station along the transect. A classic in oceanography, the CTD is the base for most research cruise operations & will be a reoccuring character in our trip as well!
This first set of science stations went really smoothly. We were able to collect all the samples we needed and although we still have a couple of wrinkles to iron out with some of our equipment, that was the point of the test stations and we’re all feeling a little bit more confident going into our first official science stations. While on station – I’m on the day shift (from 3am — 3pm, the other half of the science crew is on night shift from 3pm — 3am), we also got to see some pretty incredible views including a gorgeous sunrise (which will be our last one for a while given we’ve now crossed into the Arctic Circle where the sun always stays above the horizon in the summer months) & some wildlife!
More to come as we make our way north and start to actually sample from the Chukchi but for now … Happy Father’s Day to all the dads out there, we love and miss you and hope you’re having a great day!!
