Science at Sea: the big deal over tiny plankton

Go for launch: Marine technician Emily Shimada signals the crane operator while Megan Wilson, Rick Brodeur and Mo Schmid guide the sampling net. (Photos by Bret Yager)

THE DEEP SEA — Like a soup swimming in lights, the contents of the latest plankton trawl are a visual and scientific feast. Clustered in groups around sample dishes and microscopes or glued to monitors, the science team aboard the Research Vessel Atlantis is getting Christmas in July. 

Gifts like gelatinous arrow worms with surprising sets of jaws; doliolids that capture a meal of phytoplankton in a mucus net; and stinging jellies that dart like rocket ships, weaving whiskered copepods and larval rockfish. 

The samples seethe with life.  

“Rockfish, rockfish, rockfish, slender sole,” Chief Scientist Robert Cowen mutters, tallying quickly from a sample in the belly of the ship while on break from deploying the plankton nets, hardhat and lifejacket still on.

Cowen, director of the Hatfield Marine Science Center in Newport, is on his final cruise in a quest for data that has spanned four trips to sea over two years. In each, the strategy has been essentially the same: Take multiple samples of plankton using both nets and camera imagery to understand more about the way ocean upwellings affect the immense biomass that comprises the lower food web and, in turn, nourishes larger and larger creatures and eventually the seafood we put on our table.

The livelihoods of fishermen, the ocean’s protein source but more importantly, its health and therefore ours depend on the interactions that can be seen twinkling like tiny gems under the lens of the microscope.

The ocean’s churn

Cowen wants to grasp specifically how variations in the amount of nutrient-rich upwellings affect productivity in the ocean. The force of seasonal northwest wind powers a deep cycling of water, nourishing the surface and a web of life dependent on the sun. With the help of weather models that gauge the intensity of the winds that create the sea’s churning, it could be possible to predict productivity in much the same way that weathermen make forecasts based on the variables they see unfolding in the climate in real time. 

With this comes the potential to better understand how fish stocks are being impacted by climate and how to manage the resource with more precise science. 

“We’re trying to understand the ecosystems individually but also holistically,” Cowen explains. “Management of fisheries, mitigating climate change impacts. To mitigate we need to understand what those impacts might be. Climate and temperature patterns change and affect wind patterns, which affect upwellings, perhaps create toxic algae blooms and enhance hypoxia — or low oxygen concentrations. There are so many layers of potential interactions.”

What’s that sticky thing?

Melissa Steinman of Portland State University has set up shop in a small berth next door to the main lab, where she samples seawater captured from varying depths. A lab technician with the Center For Life in Extreme Environments, Steinman is examining microbial communities to understand, as she puts it, “what is where and who is eating who.” She also wants to know if organisms like salps carry around their own microbial communities the way humans and animals do. If it’s true, this could open an entire frontier of study into symbiotic relationships and further webs of interdependence.

“If animals on land have it, why would we not assume that it happens in the ocean?” she asks.

Outside the portals of the 275-foot Atlantis, lines of wind waves crest and charge like herds of white cattle before disappearing into the haze toward Northern California’s Trinidad Head.

In the main shipboard lab, Principal Investigator Kelly Sutherland picks through a sample dish in search of missing strands of the web. Braced against the pitching of the ship as winds peak above 40 knots, she’s gathering two species of tiny gelatinous organisms that have largely been overlooked by science: doliolids and appendicularians.

“These are grazers on phytoplankton,” Sutherland explains. “They’re more toward the base of the food web. We think fish are eating these guys, especially in the winter when there’s not as much food availability.”

The sticky creatures, easily smashed and overlooked, remain shrouded in mystery.

“With some of the groups we’re filling in the gaps,” Sutherland says. “But there are entire groups that have been ignored.”

Sutherland’s team of University of Oregon biology students use biomarkers to look at what their specimens have integrated chemically into their tissue through their meals, allowing the team to draw links down the food web.

“We’re interested in the whole web: who is eating who and how that changes with space and time,” she says. “We rely on seafood for a lot of what we eat. If we want to understand our food source and its vulnerabilities, we need to drill down and understand how things cascade through the food web.”

Moving targets

When dramatic changes strike the ocean — like “The Blob” of oxygen-depleted water that periodically hits the Oregon coast, suffocating the life in its path — it’s useful to know how relationships might shift. We still don’t know enough about these basic interactions and how material moves through the ocean, Sutherland says.

Rick Brodeur wants to probe these interactions for reasons of his own. A senior scientist with the National Marine Fisheries Service, he is trying to understand how many juvenile fish are out there and how they’re impacted by jellyfish — pervasive life forms that prey heavily on the same food sources as the tiny fish. A greater understanding of this interaction could help take some of the guesswork out of future stock assessments that determine harvest levels.

The ocean is the world’s single largest source of protein. If we max out our fisheries and then they decrease globally, Cowen says, “eventually, we are talking about the starvation of many people.”

From sudden tides of jellyfish that can devour food in one area, to unexpected waves of invaders from far waters like the pyrosomes that showed up in Oregon in 2014, real impacts can happen without much warning.

“It’s really a changing ocean,” Brodeur says. “Now it’s like every year is new. It’s hard to know what a normal situation is anymore.”

There may no longer be any such thing. But every time they dip the net and bring in another sample, the team gets closer to finding out what we need to do to safeguard the world’s most vital oxygen and food source.

“As scientists, we need to know what to expect and provide information so those in management have the best available science to work from,” Cowen says. “We’re trying to understand the overall ecosystem, how to better manage the fisheries and improve conditions by reversing negative impacts like pollution and certain fisheries practices. 

“The question is, how do we plan for and address these changes to key resources?”

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