We’ve posted a new video in the NGA LTER YouTube channel. In it, some of our graduate students (and one post-doc) describe what inspires them about working on NGA LTER science. Through these student interviews, you get glimpses of our fieldwork and what makes life aboard R/V Sikuliaq so special.
Michele Hoffman Trotter and her team collected these interviews while sailing on our Summer 2021 Sikuliaq cruise. They were also able to film the nets, instruments, and water samples that we use to investigate the NGA ecosystem. We played the video for our Site Reviewers in August, and now you get to see it too. Enjoy!
During the summer and fall 2019 NGA LTER cruises, Kira collected diapausing female copepods. She examined lipid content and cell division within the reproductive structures. Through Kira’s work, she discovered that Neocalanus flemingeri can stop diapause and begin creating egg cells within just twenty-four hours after being collected.
Annie Kandel is a master’s student through the College of Fisheries and Ocean Sciences at the University of Alaska, Fairbanks. For Annie’s thesis, titled “Spatial and temporal variability of dissolved aluminum and manganese in surface waters of the northern Gulf of Alaska,” Annie investigated the seasonal variability of dissolved aluminum and dissolved manganese in our study area. Annie derived data from the spring, summer, and fall NGA LTER cruises in 2018 and 2019.
Annie’s work showed that dissolved aluminum and manganese are trace metals that can be used as tracers of freshwater input in the NGA. This is because in this region, their main source is from rivers. Values for both metals are highest inshore, closer to the mouth of the Copper River, and decrease moving offshore.
Despite challenges and restrictions due to COVID-19, the NGA LTER was able to complete their 2020 field operations. These operations included four planned research cruises, and redeployment of several moorings.
To enable this, we shortened cruise lengths, reduced the number of participating scientist, and transferred on cruise to a different vessel. In the end, the NGA team pulled off the core Gulf of Alaska sampling and so maintained the long-term time series datasets.
Fall Cruise Update
During the first 9 days in September, twelve scientists from the University of Alaska (UAF), Western Washington University (WWU) and U.S. Fish and Wildlife Service (USFWS) sailed aboard the R/V Sikuliaq. Originally, the fall cruise was scheduled to take place on the USFWS vessel R/V Tiglax. Unfortunately, the pandemic forced the cancellation of all 2020 Tiglax sailings. Postponement of other research cruises on the Sikuliaq schedule and a slight shift of fall LTER sailing dates opened a window of availability for a fall expedition.
Fall sampling occurred in Prince William Sound and along the Seward Line. This marks the 100th occupation of the Seward Line using a (nearly) modern suite of vertically profiling sondes! The Seward Line is a 150 nautical mile transect that starts at the mouth of Resurrection Bay and extends offshore into oceanic waters. The first occupation of the Seward Line was in December, 1970. Over the first few years, samples were taken only at discrete depth levels using Nansen bottles and reversing thermometers.
A history of the sampling along the Seward Line includes:
First, sampling at Seward Line stations began with a cruise in 1970. Bottles collected water samples from depth.
Using profiling dataloggers, 17 full occupations of the Seward Line occurred from 1974 to 1997.
Then from 1997-2004, sampling expanded to 6-7 cruises per year as part of the U.S. Global Ocean Ecosystem Dynamics (GLOBEC) program.
From 2005 to 2017, cruises occurred in May and September on the Seward Line and in Prince William Sound. The consortium of funding partners include NOAA, the North Pacific Research Board (NPRB), the Alaska Ocean Observing System (AOOS), and the Exxon Valdez Oil Spill Trustee Council (EVOS) via the Gulf Watch Alaska program.
Most recently, in 2018 the consortium expanded via funding from NSF’s LTER network. The expansion includes spring, summer and fall expeditions and the addition of survey stations east and west of the Seward Line.
Despite only having three scientists aboard and working around 2 gales, the Spring 2020 cruise succeeded! That means all the cruise objectives were met during the May 4 – 10, 2020 cruise, thanks to the efforts of the entire team, including marine technicians and the whole crew of the R/V Sikuliaq. Successful elements of our cruise include:
CTD profiling of ocean physics, collections of macronutrients, chlorophyll, phytoplankton, and three size classes of zooplankton at all 15 Seward Line and 5 western Prince William Sound stations,
Recovery of the GAK1 mooring, (a year’s worth of temperature and salinity data at 6 depths) and its re-deployment for the next year, and
Re-deployment of the GEO1 mooring recovered by R/V Sikuliaq in April. This mooring includes a Profiler that will measure temperature, salinity, chlorophyll-a fluorescence, colored dissolved organic matter (CDOM), nitrate (NO3), and dissolved oxygen (DO) throughout the water column for the next year.
More Media Coverage
As discussed before, this cruise shows how science can adapt during the time of COVID-19. Since that last post, several more stories have been published.
Before the cruise departed, Alaska Public Media’s Casey Grove spoke to LTER Lead PI Russ Hopcroft. Dr Hopcroft explained why sampling this spring was necessary to understand measurements that might be more easily made later in the year, and how springtime measurements enable connections to be made between years:
Then after the cruise, EOS, the weekly magazine of the American Geophysical Union published an article about the cruise. It describes how measurements were taken while scientists and crew followed the required social distancing.
Like everyone, scientists world-wide want to reduce the spread of COVID-19. However, for their work, they also need to continue research projects that rely in part on uninterrupted data records. Fortunately, with the support of NSF and University of Alaska, NGA LTER scientists will be able to do both by reducing spring field operations.
“Pandemic carves gaps in long-term field projects” describes the importance of NGA LTER’s measurements of plankton in the spring. And it describes how R/V Sikuliaq’s crew and NGA LTER scientists quarantined in hopes that a spring cruise might be allowed (Science Magazine, mid-April.)
Importance of the Time Series
Multi-disciplinary monitoring of the Gulf of Alaska ecosystem has occurred every May since 1998. Fisheries managers and research scientists can make informed assessments of Alaska marine ecosystem health and status because of these measurements. This long-term sampling happens along the Seward Line – a set of stations stretching 150 miles across the shelf – and within Prince William Sound. Regular samples at these consistent stations insure the integrity of this time series. Therefore, preserving core physical, nutrient chemistry, phytoplankton and zooplankton data at these stations is a high priority for NGA LTER scientists.
The North Pacific Research Board (NPRB), the Alaska Ocean Observing System (AOOS), and the Exxon Valdez Oil Spill Trustee Council (EVOS) via the Gulf Watch Alaska program all provide additional funding that make this time series possible.
Our planned field work aims to continue the valuable Seward Line time series while keeping personnel safe. Before the cruise, R/V Sikuliaq remained in Seward, AK, staffed by her crew. They have been under quarantine on board since their arrival at the start of April. Three of our Principle Investigators (PIs), Seth Danielson, Ana Aguilar-Islas, and Russ Hopcroft, quarantined at home for 2 weeks. They will join R/V Sikuliaq for the 7 day cruise, May 4-10, 2020. Before the cruise, crew and science party members logged body temperatures twice daily and maintained strict adherence to social isolation protocols in order to ensure a virus-free voyage.
The cruise plan includes sampling of the entire Seward Line with additional stations in western Prince William Sound. Planned measurements include water temperature and salinity using the conductivity-temperature-depth (CTD) instrument; water collections from deep waters to the surface for chlorophyll, nutrient, phytoplankton, and microzooplankton analysis; and net tows for zooplankton.
Other common NGA LTER activities will not be possible due to the short cruise length and limited personnel. Postponed activities include shipboard experiments, seabird and mammal surveys, jellyfish sampling, dissolved iron and other trace metal sampling, carbonate chemistry sampling, and optical measurements. NGA LTER’s other cross-shelf sampling lines will not be visited.
Despite these restrictions, we are fortunate to have the opportunity to continue our work and to contribute to the goal of understanding the Northern Gulf of Alaska ecosystem.
In the deep water south of the NGA LTER study area lies an abyssal plain punctuated by volcanic seamounts – mountains that rise from the sea floor. The seamounts provide rocky, hard substrate that makes a good habitat for cold-water corals and sponges. Above the seamounts, ocean currents upwell nutrients to the surface where they feed planktonic organisms. This productivity attracts fish and seabirds to create relative hot-spots of biodiversity in the open ocean.
Immediately following the NGA LTER’s RV Sikuliaq cruise, summer 2019, several of our team members are setting out to extended our knowledge of the Gulf of Alaska. Dr. Russ Hopcroft, Dr. Petra Lenz, Dr. Vittoria Roncalli, Heidi Mendoza Islas, Callie Gesmundo, and Caitlin Smoot are joining our collaborators from Microcosm and other expedition members aboard R/V Sikuliaq to investigate seamounts in the Gulf of Alaska from an ecological perspective.
The ROV Global Explorer is a critical tool of this expedition. Operated by Oceaneering International, the ROV will take video and still images of organisms on the sea floor; this is the least-invasive method of sampling communities that could be damaged by bottom trawls and other collection methods. ROV Global Explorer will also collect fragile jellyfish by gently enclosing them in a sampler. This avoids the bias of previous sampling towards hard-shelled organisms that survive net tows.
Expedition Gulf of Alaska Seamounts 2019 will even be employing DNA sequencing to identify microbes. Previously, a NOAA Office of Ocean Exploration and Research expedition to the Gulf of Alaska seamounts in 2002 found that the corals there were distinct habitats for microbes.
The NOAA Office of Ocean Exploration and Research has created a website where visitors can follow the Mission Logs. Additionally, educators can also learn more about the expedition purpose and find videos and other classroom materials.
NOAA Office of Ocean Exploration and Research funds this project, with additional ship support by the National Science Foundation and the University of Alaska Fairbanks. Science partners during this mission include scientists from the University of Alaska Fairbanks, the University of Manitoba Canada, the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), the University of Hawaii, University of Barcelona Spain, Lamont Doherty Earth Observatory at Columbia University, the U.S. Fish and Wildlife Service, and a Microcosm film team from Montrose Pictures. The partner for the ROV is Oceaneering.
The Summer 2019 cruise aboard R/V Sikuliaq has begun. 2019 is the 50th consecutive year of samples taken at oceanographic station GAK1 (begun December 1970) and the 23nd consecutive year of Seward Line physical-chemical-phytoplankton-zooplankton-seabird sampling. However, many new things are happening too.
One of our special studies involves several days of high-resolution sampling of the Copper River discharge plume. We suspect this plume is a source of iron (and other nutrients), therefore driving some of the high productivity in the Gulf of Alaska. To investigate this, we’ll be deploying drifters, making maps of data along the plume edge, and performing incubation growth experiment using both shelf and offshore water.
In addition, the Gulf of Alaska Ecosystem Observatory (GEO) is being deployed this week. During the next year, it will report oceanographic conditions in real-time. The GEO moorings will provide the NGA LTER program with year-long data about conditions in the Gulf, so we can know what is happening even when we can’t be there. Two of the three moorings in the array report real-time data on ocean surface conditions. You can view data from these moorings in the Ocean Data Explorer system provided by AOOS and Axiom Data Science:
Internet communication with ships in the Gulf of Alaska is spotty, but these blogs will be updated as often as possible. Katie Gavenus’s completed blog from the Spring cruise gives even more insight into our work.
Yes, until now even the NGA LTER project website has overlooked jellyfish. Instead, our major research components focus on the primary producers and zooplankton that are the base of the food chain. Worse, at sea, jellyfish are often simply a nuisance whose tentacles drape on instruments and clog sensors. However, Heidi Mendoza-Islas, a graduate student in the NGA LTER project, studies the important role that jellyfish play in the Gulf of Alaska ecosystem. Read the article to find out more.
Lauren Frisch, Public Information Officer for the College of Fisheries and Ocean Sciences, UAF, authored a series of four stories about our May 2018 cruise. Although these stories focus on the on-board capabilities of R/V Sikuliaq, they also include engaging descriptions of our research. Find the links to these stories below:
Sikuliaq expands ways to study Gulf of Alaska ecosystems
Studies of zooplankton such as copepods have expanded because of LTER funding and the workspace available aboard R/V Sikuliaq. For instance, CFOS researcher Russ Hopcroft isolates, identifies, photographs, and assesses live animals soon after net tows. Read full story >>
Submarine ‘airplane’ revolutionizes measurement of seawater content
CFOS’s Seth Danielson operates an Acrobat instrument, which he described as the underwater version of an airplane. The Acrobat measures temperature and salinity on fine spatial scales. As a result, LTER scientists can track freshwater from the land and investigate how it mixes with ocean water. Read full story >>
Sikuliaq improves analysis of phytoplankton’s nutrient needs
CFOS’s Ana Aguilar-Islas brings her own specialized clean sampling instruments onto Sikuliaq so she can quantify nutrients like iron that are essential to phytoplankton. Additionally, Aguilar-Islas and WWU’s Suzanne Strom performed incubation experiments to study how iron availability affects plankton growth. Read full story >>
Nutritional flexibility in ciliates and dinoflagellates stabilizes food chains in the Gulf of Alaska. WWU’s Suzanne Strom isolates cells and preserves them soon after they are collected, so she can analyse them at sea and in her onshore lab. Read full story >>
Alicia Rinaldi-Schuler, a fisheries graduate student at CFOS, volunteered for NGA LTER’s Spring 2018 cruise aboard R/V Sikuliaq. Ordinarily, Alicia studies humpback whales. However, we put her to work sampling zooplankton on the night shift. She filmed the equipment they used (bongo nets, multi-net, and methot net) and the creatures they caught (squid, jellyfish, euphasiids, and fish larvae). Her engaging video summarizes of some of the research that occurs during our cruises.