URI scientists investigate effects of marine heat wave on ocean life off southern New England
A team of scientists from the University of Rhode Island and partner institutions departed October 13 aboard the research vessel Endeavor for a five-day cruise to investigate the implications of a marine heat wave in the offshore waters of New England.
The
waters on the continental shelf – extending from the coast to about 100 miles
offshore – have been 2 to 5 degrees Fahrenheit warmer than usual since July,
according to URI oceanographer Tatiana Rynearson, one of the leaders of the
expedition. And that warmth could have significant impacts for local fisheries
and the marine ecosystem.
“The
water is very warm compared to the average of the last 40 years,” said
Rynearson, a professor at the URI Graduate School of Oceanography who studies
plankton. “The question we’re asking is, how is it affecting the ecosystem and
the productivity of the continental shelf waters.”
The Northeast Pacific Ocean experienced a similar marine heat wave in 2014 and 2015, when what was described as a “blob” of warm water spread offshore from Alaska to California, resulting in major die-offs of fish and seabirds and closures of fisheries.
“The
impacts went all the way up the food chain from that warm blob of water,”
Rynearson said. “Similar dramatic impacts haven’t been documented for New
England waters, but we’re going to try to understand what’s going on out
there.”
Rynearson
hopes the expedition will provide a clearer understanding of how the marine
ecosystem responds to short-term heat waves and how it may react to the long-term
temperature increases that are expected in the ocean due to the changing
climate.
“We
think these heat waves will happen more frequently in the future, so it’s
important to understand how the ecosystem responds to them,” she said. “We’re
also interested in whether the response to this heat wave will give us insight
into the general warming trend.”
The
expedition – which includes scientists from the Woods Hole Oceanographic
Institute, Wellesley College, University of Massachusetts at Dartmouth, and the
National Oceanic and Atmospheric Administration – is part of a long-term
ecological research project funded by the National Science Foundation. Its aim
is to compare how variability in the environment affects the ecosystem, from
microscopic plankton to fish.
“From
our ongoing study we’ve learned that there are two different kinds of water out
there – cold, nutrient-rich water that supports a lot of fisheries production,
and warm, less-productive water,” Rynearson said. “We’re interested in the
balance between how long the waters are warm and nutrient-poor versus cold and
nutrient-rich.”
The
researchers will collect data along a transect from Narragansett to Martha’s
Vineyard and then southward about 100 miles to an area at the edge of the
continental shelf where the water is about 5,000 feet deep. Along the way they
will take water samples at various depths to evaluate how much plankton is in
the water, the rate of photosynthesis, and the rate that tiny marine animals
called zooplankton are feeding upon tiny marine plants called phytoplankton.
“We’ll
also be looking at what species of phytoplankton and zooplankton are out there,
because there seem to be differences in the community when you have cold,
nutrient-rich waters versus warm, nutrient-poor waters,” said Rynearson. “We’ll
ask, are we still seeing a summer community of marine life out there or is it
too late in the year for that.”
The
research team also aims to gain a better understanding of the marine food web
by studying the links between the tiniest creatures and the forage fish that
are fed upon by the top predators in the ocean and captured in local fisheries.
“We’re
probing a part of the food web that’s not well understood in terms of the
transfer of energy or the response to climate change,” Rynearson said. “That
part of the food web is a bit of a black hole, and we want to shine some light
in there.”
Due
to the COVID-19 pandemic, all of the participants in the expedition quarantined
for two weeks prior to boarding the ship, and fewer scientists than usual will
be aboard. Among the participants will be URI graduate students Victoria Fulfer
and Erin Jones and postdoctoral researcher Pierre Marrec.
“A
research cruise is always exciting and welcome, but during the pandemic, the
cruise participants are particularly thrilled to be out at sea,” Rynearson
said.
