Over the past few years, observers have noticed an irregularity among jellyfish on coasts across the Pacific and Atlantic. These jellyfish have been seen earlier than normal, and in larger quantities.
Julia Parrish, a professor of aquatic and fishery sciences and the dean of the College of Environment at the UW, runs the Coastal Observation and Seabird Survey Team (COASST), a citizen scientist program founded in 2000. COASST observes different coastal communities from Northern California all the way to the Arctic Circle and Russia.
After observers in this program began asking questions, Parrish and other scientists began working to answer why there were suddenly hundreds of thousands of jellyfish at a time along coasts.
The species of jellyfish the team focused on, Velella, is more commonly known as by-the-wind sailor because of its most prominent feature — a sail-like upper body that catches wind easily, causing these jellyfish to propel across the surface of the sea.
“When it washes ashore, [there] tends to be so many that they totally cover the beach, so you can’t even see the sand,” Parrish said. “They’re delicate little creatures, about the size of a Ruffles potato chip. They’re really thin and they dry out pretty quickly.”
COASST began putting their data together to find out why so many Velella were appearing along the coasts earlier than normal.
“We had to look for another forcing factor, and what we found was that when the winter is warmer than normal, we get a Velella spring,” Parrish said, “It tells us that Velella is an indicator of a warmer-than-normal marine ecosystem, but of course we don't need a jellyfish to tell us that.”
The question of why warmer waters cause a spike in Velella populations is still unanswered, but one thing is for sure: These jellyfish are benefiting from climate change, and this is evident from the population increase during springs after warm winters.
“So is a 1 degree [Celsius] change in temperature a big thing? Who knows,” Parrish said. “Well, now we know, because Velella is telling us. “A 1 degree [Celsius] shift and it’s like bam, Velella. A massive, massive change in the open ocean ecosystem and Velella is a winner.”
When a population of any given species is affected, the entire ecosystem is affected as well. There are certain members of any given ecosystem that suffer, while others flourish.
Parrish and the team at COASST have come up with some hypotheses for why this warmer water is beneficial to the Velella population.
“In a warmer winter it is less stormy, and when it is less stormy, big old waves out in the ocean break less,” Parrish said. “Velella is a little guy that is floating right on the surface of the water, so if there’s a 30-foot wave that smashes, it is literally going to pulverize Velella.”
Another hypothesis is that there is something about the warmth itself that might create more food for the Velella.
Parrish and the COASTT team found that in one year, as they were seeing more Velella, they were also seeing higher death rates of other species, including seabirds.
“We are literally driving species out of an environment when we make it so inhospitable that they can’t live there anymore,” Parrish said. “So when we talk about climate change being bad, it’s sort of short for that we are pushing the system so far and so fast that we are extincting species.”
COASST has helped to shine a light on just one of the species currently benefiting from climate change, notwithstanding its broader negative effects.
“This story showed us that there’s no way that we could collect this data any other way than with a citizen science program,” Parrish said. “On top of that, it was one of the citizens who came up with the question to ask. Scientists didn’t ask it, we just answered it.”
Reach contributing writer Mary Murphy at firstname.lastname@example.org. Twitter: @marymurphy301
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