Weather did not deter the Endurance 16 cruise to recover and deploy ocean observing equipment to ensure the continuance of data to shore for the next six months. When heavy weather closed in at the end of the second leg, the science party and crew aboard the R/V Sikuliaq met the challenge, accelerated their schedule, and arrived back in Newport on April 2, several days early.
“In spite of the less-than-ideal weather conditions, we successfully accomplished all activities with the exception of the Oregon Coastal Surface Profiler (CSPP) deployments and the Oregon offshore anchor recovery,” said Ed Dever, Chief Scientist for Endurance 16 and Principal Investigator of the Coastal Endurance Array team at Oregon State University. “When the weather cooperates, we will use a smaller vessel to deploy the remaining CSPP’s. The anchor recovery will be done during Endurance 17.”
He added, “Early spring weather in the Northeast Pacific can be unpredictable and sometimes pretty nasty for shipboard operations. We carefully monitored the weather conditions and adjusted our recovery and deployment schedule accordingly to maximize work that could be accomplished during safe weather conditions.”
[media-caption path="/wp-content/uploads/2022/04/Endurance-1.png" link="#"]Working to the weather. Spring in the North Pacific can bring pretty high winds and seas. When the Endurance 16 team had good weather, they pressed on through long days. Here Alex Wick and Kristin Politano get a subsurface float into position on the R/V Sikuliaq during an evening mooring deployment on the OOI Spring Endurance cruise. Credit: Ed Dever, OSU[/media-caption]
In spite of the abbreviated time at sea, in addition to the mooring deployments, the Endurance 16 team also successfully deployed four gliders and recovered another. And, during the second leg of the cruise, a scientific party of five that had joined the expedition succeeded in collecting and recovering sediment trap samples for an ongoing experiment led by Dr. Jennifer Fehrenbacher of Oregon State University.
The sediment traps had been collecting material in place for the past six months and were recovered during the Endurance 16 team’s recovery and deployment work. Once the traps were back onboard, the collecting cups were taken off, emptied, replaced, and the traps redeployed for another six-month period. The researchers packaged the collected materials for analysis at OSU and her collaborators at the University of South Carolina.
The team also analyzed live specimens from night-time plankton tows, which took advantage of the quiet night-time hours when the Endurance team was unable to safely move large, bulky, equipment in the dark.
Added Dever, “Success at sea is about teamwork, and I really appreciate the science party and the captain and crew of the R/V Sikuliaq. Everyone was flexible and willing to work long, arduous hours to get the job done.”
[media-caption path="/wp-content/uploads/2022/04/Endurance-in-port.png" link="#"]At the end of an expedition everyone’s eager to get home. Here the R/V Sikuliaq approached NOAA’s pier in Newport, OR, but there was one more chore to do – get that recovered equipment off the deck. The motivated crew and science party cleared the deck within 2 and half hours of docking! Photo: Ed Dever, OSU[/media-caption]
Oregon State University Assistant Professor Jennifer Fehrenbacher needed a ship to carry out her National Science Foundation-funded research investigating the lives of foraminifera (single-celled organisms about the size of a grain of sand and smaller) in the northern Pacific. Her work, in collaboration with Dr. Claudia Benitez-Nelson at the University of South Carolina (UofSC), involves deploying bottom-moored sediment traps and collecting plankton tows while at sea, giving researchers the opportunity to explore foraminifera that live in lighted surface waters, and how these communities have changed over time in response to the surrounding ecosystem.
Fehrenbacher found her ship. She will be joining forces with the Endurance Array Team aboard the R/V Sikuliaq during its bi-yearly expedition to recover and deploy ocean observing equipment at its array in the northeast pacific off the coast of Oregon. Fehrenbacher and her team of four researchers will join the Endurance Array 16 team in early April for the second of its two-leg expedition. This will be a continuation of her research project that began in September 2021.
Last September, Fehrenbacher’s team put in place two tandem sediment traps that are located close to the OOI Slope base node. One was deployed at about 600 meters water depth, the other slightly above the sea floor. The last sediment trap study in this region was conducted around 30 years ago, and the foraminiferal species have likely changed since then, as have ocean conditions.
[media-caption path="/wp-content/uploads/2022/03/IMG_5185-copy.jpg" link="#"]Fehrenbacher’s team will be retrieving two tandem sediment traps that are located close to the OOI Regional Cabled Array slope base node. Credit: Jennifer Fehrenbacher, OSU.[/media-caption]
The sediment traps have been collecting material in place for the past six months and will be recovered along with the Endurance 16 team’s recovery and deployment work. Once the traps are back onboard, the collecting cups will be taken off, emptied, replaced, and the traps redeployed for another six-month period. The researchers will package the collected materials for analysis at OSU and UofSC.
The team also will be examining live specimens from night-time plankton tows, taking advantage of quiet night-time hours to conduct the plankton tows when the Endurance team is unable to work safely moving large, bulky, and unwieldy equipment in and out of the ocean. “This arrangement is a win-win for everyone,” said Endurance Array Chief Scientist Ed Dever. “It maximizes the use of ship time, while helping to provide data to answer some questions about how ocean conditions are changing.”
Fehrenbacher’s team will be conducting a series of discrete new tows from the surface to about 500 meters. “While I don’t anticipate a ton of critters in the really deep water, net tows haven’t been done extensively in these waters at these depths. The last one was 30 years ago by oceanographer Alan Mix and his graduate student Joseph Ortiz, so this new work will give us insight into how life in the water column may have changed over time, “ said Fehrenbacher.
Fehrenbacher’s team will be conducting experiments with live foraminifera in a portable travel lab they will bring onboard. A number of different experiments are planned:
PhD candidate Kelsey Lane will be collecting foraminifera (shortened version “forams”) to study their genetics and their microbial communities, other species living with forams.
Graduate student Grace Meyer will be striving to measure carbon and oxygen isotopes in individual forams. She will be collecting empty shells from both the water column and sediment trap material and compare what is found in both, providing information about water column processes that could alter shells’ composition.
Postdoctoral researcher Brittany Hupp will be collecting both live forams and empty shells to study the chemistry of different types of forams, looking at their isotopes and trace metals content.
Researcher Eric Tappa, a sediment trap expert from the UofSC, will be deploying and recovering the sediment trap equipment. Tappa has been working with sediment trap moorings for decades and have proven critical in providing longer time-series records of processes occurring in overlying waters.
As lead scientist Fehrenbacher will be participating in these onboard experiments. She also will be growing forams under controlled conditions and watching them to learn how temperature modulates their shells or their behaviors during the day-night cycle, and will continue her work with recovered forams once she returns to her home lab. There she will be measuring the trace element concentrations in foram shells so results can help inform the Paleo record. . She explained, “Foram shells are used basically as proxies for environmental conditions. So when we measure trace elements in their shells, this gives us information about the pH, temperature, nutrient content, and even the salinity of the ocean in the past.” The onboard experiments help scientists under how forams incorporate these elements into their shells when they are alive, which they can use in assessing past records.
[media-caption path="/wp-content/uploads/2022/03/IMG_5196-copy.jpg" link="#"]An anchor weighing ~2500 pounds is deployed to keep a sediment trap in place for six months until it is recovered with a treasure trove of marine life and particulates for investigation. Credit: Jennifer Fehrenbacher, OSU.[/media-caption]
Challenges of studying small living things
Studying single-celled organisms is difficult on dry land, but is compounded by a moving ship in rolling seas. Fehrenbacher’s team will be taking onboard multiple microscopes, including an inverted microscope to see their subjects, water circulators to keep them at constant conditions while they are alive, and a pH meter. High-powered microscopes are critical for the work because forams range in size from smaller than a grain of sand—about 100 microns— to up to about a millimeter.
“We look at forams in a petri dish under the microscope,” explained Fehrenbacher. “This is challenging as the ship moves back and forth so does the water in the petri dish so you’re looking back and forth as the ship moves.” The researchers have come up with the solution of holding the petri dish at an angle so the water and foram stay in one place and helps prevent researchers’ sea sickness.
Fehrenbacher predicts that the amount of material collected on the Endurance Array 16 cruise will keep she and her graduate students busy for at least the next two years and beyond. She added, “There’s really just nothing quite like the type of information you can get from sediment trap studies. While going out to sea for two weeks a year and doing plankton tows are helpful, we only get information about what’s in the water column at the exact moment of collection. But sediment traps provide months’ worth of data at really high resolution that we can compare with other OOI data and get a detailed picture of ocean conditions and how those conditions affect marine life.