Wednesday, July 28, 2021
July 28, 2021

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Years after the devastating ‘Blob,’ ocean conditions appear to be improving, plankton survey shows

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Some are iridescent, shimmering blue as sapphires in the sea. Others have a space alien visage, rivaling anything Hollywood could come up with. Some sprout spines. Others glow at night with bioluminescence.

Plankton — from the Greek word meaning drifter — are the base of the marine food chain. And for the first time since a devastating marine heat wave that peaked through 2014 and 2015, researchers see in the abundance, condition and diversity of plankton recently sampled off the West Coast signs of a change for the better in ocean conditions.

While it’s early days for data that is still being analyzed, Jennifer Fisher, a plankton ecologist with Oregon State University, reported seeing an abundance of plankton associated with cold water upwelling, and good fat levels and size in zooplankton, the tiny animals that feed the food web.

“We are seeing a high biomass of copepods and they also are big,” Fisher said by phone on a shore break during an ocean survey.

Reddish slime in a plankton net: That was a thing of beauty to her. It’s Neocalanus spp., a type of copepod — a zooplankton — not seen during The Blob, as the massive marine heat wave came to be called.

“This is the first survey I have been on where I saw so many nNeocalanus, the sieve is just bright red,” Fisher said. “That is them.”

The research is part of a Northern California Current Ecosystem Survey that has been ongoing with multiple funding sources since 1996. Fisher was aboard the National Oceanic and Atmospheric Administration’s research vessel Bell M. Shimada, on a 12-day research cruise that began May 22.

Researchers with multiple entities assigned to a range of projects were at sea, traveling from northern Washington to the Oregon-California border, and offshore to 200 nautical miles from Newport, Oregon, and 150 nautical miles off Crescent City, California.

They used an array of devices to sample everything from plankton collected throughout the upper 100 meters, or 328 feet, of water, and monitoring conditions such as temperature, oxygen levels, salinity and other variables to an ocean depth of 3,500 meters, or more than 11,000 feet.

The team wasn’t looking for fish — but the tiny things that feed them, using nets to sample the biodiversity, size and nutrition levels of phytoplankton — tiny plants — and zooplankton — equally tiny animals — in the marine food web.

A high resolution microscope in the ship’s lab revealed an unseen world all around us. “What I love about it, too, is you take a cup of water and look at it under a microscope, and you would be amazed at how much life there is,” Fisher said.

There are strong correlations between this food web and salmon returns, and even seabirds such as marbled murrelets that travel 50 and more miles from their forest nests to feed at sea.

The long-term ecosystem survey is invaluable for showing trends in ocean conditions. Those took a dramatic turn starting in the fall of 2013, as The Blob began building.

Eventually the mass of warm water engulfed the entire West Coast, leaving animals nowhere to go to find better conditions. Millions of animals died of starvation, from seabirds to salmon to sea lions. The effects are still being felt, particularly in diminished salmon runs. Years of data recorded in the online ocean indicators webpage maintained by NOAA show near-historic poor ocean conditions in recent years.

Salmon begin their life in fresh water but migrate to the ocean where they typically live from two to four years, and must gain all of their body size. The ocean food web is critical to baby salmon sizing up fast — to get bigger than a bird’s beak or predator’s mouth.

Off Newport, the first day out from the home port, Fisher reported good news for baby salmon. From her first dispatch:

“The plankton nets inshore were pretty brown with phytoplankton, and goopy with a variety of gelatinous organisms. However, beneath all the ‘gunk’ a rich copepod community existed with lots of northern copepods. We collected quite a few adult krill at the shelf break, and offshore the water started to clear and was filled with Neocalanus — a copepod indicative of productive water. This copepod species has been observed during recent surveys, but was absent during the MHW (marine heat wave) years.”

The water column was cold at just 8 degrees Celsius or 46 degrees Fahrenheit at depth, with no hypoxic water — all good news for sea life.

“Long story short — all signs point toward a cool and productive ecosystem so far,” she reported.

On May 26, offshore of Crescent City, Fisher reported calm seas — and even a total lunar eclipse for the night crew, pulling nets of plankton that migrate to the top of the water column nightly.

The team continued to find Neocalanus, and a good size range of krill, a tiny crustacean that feeds everything from salmon to humpbacks. The phytoplankton community near shore was dominated by thalassiosira — chains of golden diatoms, indicative of the upwelling water that feeds the web of life.

Diatoms are autotrophs, meaning they make their own food from the energy of the sun, by the process of photosynthesis. These brown-green algae cells are encased in a silica shell — giving diatoms a spangled, jewel-like appearance under the microscope.

But their wealth is counted in nutrition: Diatoms are packed with fatty acids that move up the food web from one animal to the next. This is the primary production on which the salmon in an orca’s mouth depends.

It all starts with the Northern California Current, the upwelling that brings cool, nutrient-rich bottom water refreshing the warm, nutrient-depleted waters at the surface. These upwelling nutrients and the long daylight hours fuel a burst of diatoms that stoke marine productivity.

Another good sign: On May 31, Fisher reported marine mammals, mostly humpbacks, but also a pod of orcas and fin whales observed nearly continuously, and in high abundance, from the Columbia River to La Push. They go where the food is.

With the samples from this most recent survey back at the lab in Newport, of course now even more work begins: analyzing some 150 plankton samples for nutrients, genetics, chlorophyll levels and more.

With all that work ahead, it’s too soon to say for sure, but the signs are encouraging, Fisher said, in a region starved for good news about ocean conditions.

“I feel like the ocean is productive so far this year; that is my hunch.”

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