July 22, 2016 — NEWPORT, Ore. — In a cold mist under gray skies, the Pacific Ocean heaved against the boat as two scientists from Oregon State University pulled a net full of life from the deep.
It was a July day, but it felt like a day in December.
In the net life swarmed, much of it too small to be seen with the unaided eye. The net held the keys to help scientists unlock how creatures of the sea are affected by changing ocean conditions and those effects on the aquatic food chain. And more specifically, the effects to salmon, a fish of much importance to humans.
For 20 years scientists have made bi-monthly trips on what is called the Newport Hydrographic Line, which takes them to the same seven sampling stations along a 25-mile path perpendicular to the coast. The stations are physical points on a map. There are no buoys or other structures that mark their locations. The scientists find them using GPS.
They launch their research vessel, the R/V Elakha, from a dock in Yaquina Bay that sits along a jagged bulge of land on which OSU’s Hatfield Marine Science Center resides. The trips have amassed an extraordinary amount of data about the sea and the life within it. The data is routinely posted on the National Oceanic and Atmospheric Administration’s Northwest Fisheries Science Center website and is used primarily to help forecast salmon runs. But the data has also told the story of changing ocean conditions and its impact on the food chain.
“We can also look at the changes in the bioenergetics of the food chain across the whole 20-year time series,” says OSU research assistant Jennifer Fisher. “It doesn’t just relate to salmon; it relates to sardines and (other) fish. It gives us an idea of ocean acidification, toxic algae – lots of things.”
Fisher has been going on these trips to sea for five years aboard the 54-foot research vessel owned and operated by OSU.
On this day, Fisher, OSU lab technician Tom Murphy and deckhand Dave Weaver use two different cone-shaped nets to capture organisms that live in the sea and that form the basis of the oceanic food chain.
Fisher’s primary interest in the day’s catch is in a tiny crustacean called a copepod. These creatures feed on the sea’s phytoplankton. Copepods are animals with large antennae and are only a millimeter or two in length. Under a microscope their bodies are an elongated oval protected by an exoskeleton. But they are nearly transparent. And inside their bodies scientists have discovered a lipid sac, or stored fat.