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!
Massive, early spring bloom in the northern Gulf of Alaska, April-May 2021
Some of the highest chlorophyll concentrations recorded during the 24-year occupation of the Seward Line were seen in late April – early May 2021, in association with a massive spring bloom of diatoms. As an illustration, satellite imagery from NASA’s VIIRS (Visible Infrared Imaging Radiometer Suite) shows the bloom developing rapidly between April 18th and 25th.
Field sampling provided details
Our field sampling from R/V Sikuliaq coincided with this bloom. We found relatively cool ocean temperatures and, in places, fresher conditions than usual, as shown below for the GAK line. High chlorophyll was mostly confined to the upper 20 m of the water column (as seen in the fluorescence section below). Likely, this bloom was a response to intermittent sunny days and light winds. Late April chlorophyll-a concentrations reached almost 30 μg liter-1 on the inner MID line. In contrast, in some springs the peak concentrations are only one-tenth this level. Surface macronutrients (nitrate and silicic acid) had been drawn down to levels usually observed in summer (<1 μM liter-1).
Microscopy conducted on board showed a diverse mixture of chain diatoms and colonial Phaeocystis comprising the bloom phytoplankton community. Concurrently, late-stage juveniles of the spring dominant Neocalanus copepod community had large amounts of lipid stores. At some stations, these copepods were already beginning their seasonal descent to deep diapause depths. Conversely, seabird abundances were some of the lowest ever observed during the >20-year time series, and few marine mammals were sighted.
The early, intense bloom of large, lipid-rich phytoplankton bodes well for survival and growth of krill and larval fish in 2021.
For further information contact Russ Hopcroft (firstname.lastname@example.org) or Suzanne Strom (email@example.com)
The Northern Gulf of Alaska Long Term Ecological Research (NGA LTER) project invites undergraduate students to participate in our interdisciplinary oceanographic research this summer. This cohort of REU students will join our team from June 15 to August 20, 2021. The application period closes February 15, 2021; applicants will be notified in mid-March.
The NGA LTER is one site within the national LTER network. Our research team investigates the features, mechanisms, and processes that support NGA ecosystem production and foster its resilience. Scientists conduct field work, including ship-based experiments, run computer models of the ocean, and communicate findings to students and the public through education and outreach partners.
We seek highly motivated undergraduates with interest in marine science, biology, chemistry, and/or physics to work with scientists through the University of Alaska Fairbanks. Student research will integrate with work currently being done on the NGA LTER ecosystem. The time period of this REU position includes our summer cruise aboard R/V Sikuliaq, so participation in ship-board research activities is possible, as is historical time series or retroactive data analysis. Oceanographic research themes include biogeochemical cycling, microplankton ecology, physical oceanography, chemical oceanography, zooplankton ecology and molecular studies. For more information on potential research projects, please see potential projects and mentors, listed below.
Stipend of $5760 for a full-time position (40 hours per week) over 10 weeks.
Additional funds may be available to offset housing and transportation costs.
College level background in biology, chemistry, physics, or marine science.
The ability to carefully follow instructions.
Desire to work in a team setting.
Upper division status in a Bachelor of Science program.
An interest in continuing scientific research upon graduation.
How to Apply
Applicants must be citizens or permanent residents of the U.S. and its possessions and must be enrolled in a 2- or 4-year institution of higher education. Students who have received a bachelor’s degree before the start date of the program are ineligible. Members of groups under-represented in earth and environmental science are strongly encouraged to apply.
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 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.
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.
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.