Charles Cousins and Hannah Kepner work on the ISIIS-DPI system on the deck of the R/V Sikuliaq before the start of the spring cruise.
That’s a wrap on the 2022 NGA LTER field season! In late April the season started with a chilly expedition aboard the R/V Sikuliaq. Although storms battered our efforts, the weather cooperated enough for us to complete all of our sampling lines, as well as deployment of the Gulf of Alaska Ecosystem Observatory moorings. These moorings allow for collection of in-situ data.
Sierra Lloyd, Ana Aguilar-Islas and Emily Ortega sampled water chemistry parameters during the summer cruise. Photo courtesy of Emily Ortega.
The summer Sikuliaq cruise forged ahead, despite weather and COVID challenges. Scientists expanded upon regular grid sampling by conducting more in-depth examinations of the role of the Copper River’s freshwater input to the NGA. This included small-boat operations around the mouth of the Copper River.
The fall expedition aboard the R/V Tiglax began right on schedule. Luckily this was immediately after a major storm event passed through the Gulf. The science team was able to keep on pace, and completed all sampling along the Seward Line and into Prince William Sound.
Rainbow over the Gulf of Alaska, captured from the stern of the R/V Tiglax.
Many fall cruise participants departed straight from the ship to meet colleagues at the 2022 LTER All Scientists’ Meeting. The meeting was held September 19-23 in Asilomar, CA. After a long time apart, it was great to join together with members from other LTER network sites.
Our NGA LTER team will gather again in Fairbanks in December. The goal will be to share recent findings, and plan ahead for 2023 and beyond.
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!
Megan is a master’s student studying phytoplankton in the NGA. Her thesis is titled “Cryptophytes in the Northern Gulf of Alaska: an analysis of distribution and regulation of mixotrophy.”
Massive, early spring bloom in the northern Gulf of Alaska, April-May 2021
Satellite measurements
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.
Satellite measurements of Chlorophyll-a in the Gulf of Alaska, April 18, 2021 [Credit: Rachel Potter from NASA VIIRS data]Satellite measurements of Chlorophyll-a in the Gulf of Alaska, April 25, 2021 [Credit: Rachel Potter from NASA VIIRS data]
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).
Anomalies of temperature and salinity along the Seward Line, spring 2021 [Credit: Seth Danielson]Fluorescence along the Seward Line, spring 2021 [Credit: Russ Hopcroft]
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.
Planktonic organisms in the Gulf of Alaska, Spring 2021
For further information contact Russ Hopcroft (rrhopcroft@alaska.edu) or Suzanne Strom (stroms@wwu.edu)
Students setting up deckboard incubators aboard the R/V Sikuliaq during our 2019 REU program.
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 may include 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.
Details
Salary
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.
Qualifications
Required:
College level background in biology, chemistry, physics, or marine science.
The ability to carefully follow instructions.
Desire to work in a team setting.
Communication skills.
Desired:
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.
To apply, submit each of the following:
Cover letter
Resume
Make sure your resume includes:
Contact information: email address and telephone numbers
Kira taking zooplankton samples aboard the R/V Tiglax. Photo credit: Mette Kaufmann
Kira is a master’s student in the Marine Biology Graduate Program at the University of Hawaiʻi at Mānoa. Her thesis is titled “Characterization of Cell Division in the Tissues of the Calanoid Copepod, Neocalanus flemingeri from Diapause through Early Oogenesis.”
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.
From Kira’s thesis: cell division in the ovaries of a sub-Arctic copepod, Neocalanus flemingeri. Fluorescent microscopy photo showing the start of egg cell creation. Blue cells are non-dividing cells of the ovary and red cells are dividing egg cells. The ov and white outline indicates where the ovary is, and the od shows the oviducts. (A) Females have not started egg cell creation three hours after collection. (B) Females have started creating egg cells twenty-four hours after being collected, as shown by the red cells in the ovary.
Sampling the CTD: Annie filtering nutrient samples aboard the R/V Sikuliaq.
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.
Annie’s thesis data: surface concentrations of dissolved aluminum [Al] and dissolved manganese [Mn] during the summer 2019 Copper River plume study. Shown are 50 m, 100 m, and 250 m bathymetry contours.
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.
CTD data from the Seward Line, May 2020.
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:
The Sun sets through an R/V Sikuliaq window in May 2020. Credit: Seth Danielson
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.
Citation: Duncombe, J. (2020), What it’s like to social distance at sea, Eos, 101, https://doi.org/10.1029/2020EO144098. Published on 12 May 2020.
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.
The research vessel Sikuliaq, here in Seward, Alaska, will depart May 4, 2020. [credit: Sarah Spanos]
Evolution forced by COVID-19
Like other research programs, our research plans shifted rapidly in response to the changing situation. Several articles trace this evolution by featuring NGA LTER PIs and research activities.
“At UAF, two major programs highlight the struggle” describes the announcement by the University-National Oceanographic Laboratory System (UNOLS) to stand down the academic fleet until July 1, 2020. Since our Spring and Summer cruises were scheduled on the UNOLS vessel R/V Sikuliaq, this directly endangered our program (our local newspaper, the Daily News Miner, mid-April.)
“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.
Nearly 50 years of data have been collected at GAK1, a Seward Line station. This allows the calculation of long-term trends and anomalies. [credit: Seth Danielson]
The Plan
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.
Bathymetric map of the Gulf of Alaska, showing its deep basin with seamount chains. Grey – land, Green – continental shelf, Yellow – continental slope, Orange – deep basin. [credit: Seth Danielson]
The Expedition
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.
ROV Global Explorer by Oceaneering has a multitude of imaging and sampling capabilities ideal for deepwater exploration. [credit: Katrin Iken]
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.
Follow Along
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.
Benthic collage. [credit: Gulf of Alaska Seamounts 2019 Expedition]
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.
