NOAA Teacher at Sea
Aboard R/V Sikuliaq
June 29 – July 18, 2019
Mission: Northern Gulf of Alaska (NGA) Long-Term Ecological Research (LTER)
Geographic Area of Cruise: Northern Gulf of Alaska
Date: July 3, 2019
Weather Data from the Bridge
Latitude: 58° 54.647’ N
Longitude: 146° 00.022’ W
Wave Height: 4-5 ft.
Wind Speed: 1.9 knots
Wind Direction: roughly 90 degrees, but variable
Visibility: 1 nm
Air Temperature: 13.2 °C
Barometric Pressure: 1014.4 mb
Sky: Clear, then foggy
We have been fortunate so far to have very calm conditions. Winds have been variable or light and are expected to continue to be so through the weekend at least. Wave heights have generally been about 3 feet, although they’re up to 4-5 feet today, and are expected to drop tomorrow. The calm weather is critical for some of the testing being done, and thus is allowing more to happen.
Science and Technology Log
The focus of all of testing on board is plankton. As the base of the food web, all species depend on their health and abundance for survival. There are multiple teams who are focused on various aspects of plankton and their reaction to environmental conditions. Kira Monell is a graduate student at the University of Hawaii at Manoa who is working under the direction of Dr. Russ Hopcroft while on board. She is studying zooplankton, or the animal version of plankton. She is specifically focusing on Neocalanus flemingeri, a type of sub-arctic copepod. It is important to study zooplankton because they provide a link between phytoplankton (the plant version of plankton) and larger fish on the food web. Copepods are extremely abundant and varietal, found just about everywhere in the world. They are an important food source for most aquatic species (they exist in both salt and fresh water). They are a trophic link – a connection in the food web. Her target species is special because they mostly eat phytoplankton during the seasonal plankton blooms. They convert their food into a lot of lipids (fats) and thus are great sources of food and energy for larger fish. After fattening up, they go deep into the ocean to hibernate around mid-summer.
Kira is specifically focused on the termination of their hibernation (technically called diapause). She is doing genetic testing to see which genes are activated or deactivated during this phase of their lives. Messenger ribonucleic acid (or mRNA) coded by these genes is required to construct the enzymes that cause changes in body functions, so she is looking at levels of different mRNA in the copepods. She is expecting to see an increase in genes relating to oogenesis (egg formation). Her female copepods go into diapause ready to start making eggs, so she expects to see changes in genes relating to egg growth as they come wake up from diapause.
Kira is examining copepods through three different experiments. With some samples, she adds a stain called EDU (a dye that labels cells that are just about to divide) into her samples and then checks them at 24 hours to see which cells have divided. Because the copepods are still alive, she can check back to see what further cell division have happened over longer periods of time. A fluorescent microscope is required to see the EDU. Scientists still struggle to understand what actually triggers emergence from diapause since deep water copepods don’t experience seasonal light changes, or other potential triggers that might exist on the surface.
Another thing she is looking at is in-situ hybridization. She makes a tag that is very specific for the gene she wants to examine. When the probe gene is introduced, it attaches to the gene she wants to look at only if it is being actively copied. Kira then attaches a colored or fluorescent dye to the probe and in that way she can track which genes are being expressed in specific areas of the body.
The third project that she is working on is trancriptum analysis, which requires building a complete “catalog” that shows all the RNA used by a species. She can then look at which gene transcripts are present, and in how abundant they are, so as to compare them to the “average” version of a transcriptum to see which genes are being turned off and on under certain conditions.
To obtain samples of copepods, the zooplankton team, including Kira, uses Calvet nets. These are four long nets that terminate in collection tubes. Weight is added to the bottom of the nets and they are submerged off the stern to 100 meters of depth and then pulled back up (a process that takes roughly five minutes). The nets are then rinsed to collect the samples in the tubes, which are transferred into jars and brought to the lab for more detailed sorting and examination.
As the Calvet rises you can see the full net. (This video has no dialogue.)
Getting prepared to go out on deck safely!
All of the sample collection happens on the working deck at the stern of the R/V Sikuliaq or in the adjacent Baltic Room. The back deck is equipped with a variety of cranes and winches that are designed to handle heavy weights and lines under tension. As such, it is critical to wear the proper protective gear when you’re out there: boots (preferably steel-toed), a hard hat and a flotation vest of coat. If there’s a potential to get wet or dirty, rain gear or waterproof bibs are essential to stay dry and relatively clean. Being properly dressed is a process that took getting used to, but now it’s habit. Again, we’re lucky to have had good weather, so the deck is usually warm enough to wear a t-shirt and jeans. I find it calming to be outside, so I am enjoying learning about the sampling methods of other teams by watching and sometimes assisting them. There are also observation decks at the bow that do not require safety gear. A few of us have discovered that the forward decks are much quieter and are good spaces to decompress and look for sea life.
Animals Seen in the Last 24 Hours:
We’ve seen a few species of birds including black turnstones, glaucous-winged gulls, Black-winged kittiwakes, as well as deeper water birds such as storm petrels and shearwaters. In addition, there have been small pods of dolphins in the distance and one humpback whale (all we saw was the tail).