NOAA collects critical data amid COVID-19 cancellations

While COVID-19 halted most 2020 ocean research, NOAA’s Oscar Dyson sailed one research cruise this fall that attempted to pick up the slack, sailing from Kodiak to the waters north of Utqiagvik and back to collect a broad array of data. The results appear to show a promising return of the “cold pool” to the North Bering Sea with some concerning caveats, although much of it remains to be analyzed and many questions remain unanswered.

The traveled more than 3,700 miles and spent 25 days at sea, uploading data from preset observation sites as well as making observations of its own. It picked up a number of tasks from other researchers whose ships couldn’t sail this summer and was able to accomplish almost all of its objectives, stymied only twice by bad weather.

Phyllis Stabeno, an oceanographer with NOAA’s Pacific Marine Environmental Laboratory who gave a talk about the Oscar Dyson’s cruise, said that while the data collection was incomplete, the fact that they were able to get any data at all in a year devoid of field research was a major accomplishment.

The cruise was originally set to have nine scientists, a skeleton crew compared to previous years, in an attempt to keep COVID-19 off the ship. The scientists traveled from their home institutions into a shore quarantine and were tested to make sure they were negative before they boarded the ship.

“And to our immense horror, one person tested positive for the coronavirus, and five other people had been exposed or were in contact,” Stabeno said. “And so instead of sending nine people on a cruise that we needed 15 people on, three people went to sea.”

The three scientists, two oceanographers and a bird observer, worked with the ship’s crew to collect a huge array of data on their month-long voyage, from checking observatories and mooring sites to collecting environmental DNA, conducting zooplankton tows, observing marine mammals and birds and more.

“The NOAA ship Dyson and the officers and crew stepped forward and did a remarkable job in helping to sample,” Stabeno said. “All of this stuff was done because everybody worked above and beyond what was really reasonable.”

This year was anticipated to be an interesting one for climate and fisheries scientists in the Bering Sea region. The alarming results from the research seasons of 2018 and 2019 that found a complete absence of the ice-driven “cold pool” were followed by a cooler winter that saw thin sea ice extending farther south than it had in the previous few years.

The cold pool is a mass of dense, salty, colder-than-freezing water that usually settles to the bottom of the North Bering Sea when annual sea ice extends south into the region. It provides a critical “thermal barrier” between frigid Arctic waters and the relatively warmer water of the South Bering Sea. That frigid barrier keeps out fish species like pollock and Pacific cod and is an important factor in the North Bering Sea’s uniquely vibrant ecosystem, supporting everything from algae and small fish to seabirds, walruses and whales.

In 2018 and 2019, NOAA conducted bottom trawl surveys to map the extent of the cold pool, and they were alarmed to find that it was almost entirely absent from the Bering Sea. Large predatory fish species, such as pacific cod and pollock, were found in unusually large numbers north of St. Lawrence Island, and the entire marine ecosystem appeared to be in a state of flux.

The 2019/2020 winter was colder by comparison and saw sea ice extending farther south, so scientists were excited to see if the cold pool had been restored. But then came COVID-19, cancelling the bottom trawls and leaving scientists in the dark. “It’d be really, really nice to be able to have a better map of where the cold pool is,” Stabeno said.

The Oscar Dyson didn’t have the capabilities to conduct a full bottom trawl survey, but it did collect temperature data from a series of permanent observation stations scattered around the Bering Sea. One site in the south, near the Aleutian Islands, recorded extremely warm bottom temperatures around 4°C [39.2°F]. Stabeno said that’s comparable to 2018, the warmest year on record, but not altogether unsurprising given that the area saw no sea ice this winter.

Two sites farther north were under solid ice for the entire winter, and they recorded temperatures around -1.6°C [29.12°F]. Based on this limited data, Stabeno said the cold pool probably extended south of St. Lawrence Island all the way to St. Matthew Island, a promising sign after two years of no cold pool at all.

Some questions remain unresolved, though. The mathematical model used to predict ocean temperatures proved wrong in a number of areas, and temperatures were generally warmer than the model predicted, suggesting that scientists need to refine the way they predict ocean dynamics.

The data collected by the Oscar Dyson is also incomplete compared to previous years and may not lead to any huge revelations. But Stabeno was glad that any data could be collected at all and was hopeful about the future.

She was especially excited about this year’s campaign to deploy “Pop-Up Buoys,” a new technology that Stabeno said could greatly improve the amount of data available to scientists. When deployed, the buoys sink to the bottom of the ocean, where they record all kinds of data, including temperature, for a preprogrammed amount of time. When time runs out, they automatically float to the surface, collecting even more information throughout the water column on their ascent.

The beauty of the system, Stabeno said, is that the buoys are relatively cheap and easy to operate, so they can be deployed all across the region not just by research vessels but by commercial fleets, the military, and local communities to get a more detailed map of a changing ocean. The system was especially valuable this year because COVID-19 kept so many research vessels in port. As it rushed along the entire western coast of Alaska, the Oscar Dyson was only able to deploy six of the 14 planned buoys. So they coordinated with the commercial fishing fleet to deploy four, and the Coast Guard to deploy another two. The community of St. Paul has the last one and is set to deploy it as soon as the weather permits.

“And this is what we were hoping that these pop ups would eventually enable us to do, that we could observe different parts of the ocean with help from communities, from the fishing industry, other commercial vessels or ships of opportunity,” Stabeno said. “And that in itself was an immense success.”

She emphasized that a lot of the raw data collected by the Oscar Dyson remains to be analyzed, so not many firm conclusions can be drawn yet about fish populations or the future of sea ice in the region. But in a year that will be largely blank on the scientific record, she considered it “nearly a miracle” that the Oscar Dyson was able to collect any data at all.