Saving Seafood

NASA-funded Study: Gulf of Maine’s Phytoplankton Productivity Down 65%

June 8, 2022 — The Gulf of Maine is growing increasingly warm and salty, due to ocean currents pushing warm water into the gulf from the Northwest Atlantic, according to a new NASA-funded study. These temperature and salinity changes have led to a substantial decrease in the productivity of phytoplankton that serve as the basis of the marine food web. Specifically, phytoplankton are about 65% less productive in the Gulf of Maine than they were two decades ago, scientists at Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine, report in new results published today.

The Gulf of Maine helps fuel New England’s marine ecosystems and economy. Like plants on land, phytoplankton absorb carbon dioxide from the atmosphere and use photosynthesis to grow, and then become a food source for other organisms. Disruptions to their productivity can lead to adverse effects on the region’s fisheries and the communities that depend on them.

“Phytoplankton are at the base of the marine food web on which all of life in the ocean depends, so it’s incredibly [significant] that its productivity has decreased,” says William Balch, the Bigelow Laboratory scientist who led the study. “A drop [of] 65% will undoubtedly have an effect on the carbon flowing through the marine food web, through phytoplankton-eating zooplankton and up to fish and apex predators.”

Read the full story from NASA

Robotic Floats Provide New Look at Ocean Health and Global Carbon Cycle

August 18, 2021 — Microscopic marine life plays a fundamental role in the health of the ocean and, ultimately, the planet. Just like plants on land, tiny phytoplankton use photosynthesis to consume carbon dioxide and convert it into organic matter and oxygen. This biological transformation is known as marine primary productivity.

In a new study in Nature Geoscience this week, MBARI Senior Scientist Ken Johnson and former MBARI postdoctoral fellow Mariana Bif demonstrated how a fleet of robotic floats could revolutionize our understanding of primary productivity in the ocean on a global scale.

Data collected by these floats will allow scientists to more accurately estimate how carbon flows from the atmosphere to the ocean and shed new light on the global carbon cycle. Changes in phytoplankton productivity can have profound consequences, like affecting the ocean’s ability to store carbon and altering ocean food webs. In the face of a changing climate, understanding the ocean’s role in taking carbon out of the atmosphere and storing it for long periods of time is imperative.

“Based on imperfect computer models, we’ve predicted primary production by marine phytoplankton will decrease in a warmer ocean, but we didn’t have a way to make global-scale measurements to verify models. Now we do,” said MBARI Senior Scientist Ken Johnson.

By converting carbon dioxide into organic matter, phytoplankton not only support oceanic food webs, they are the first step in the ocean’s biological carbon pump.

Phytoplankton consume carbon dioxide from the atmosphere and use it to build their bodies. Marine organisms eat those phytoplankton, die, and then sink to the deep seafloor. This organic carbon is gradually respired by bacteria into carbon dioxide. Since a lot of this happens at great depths, carbon is kept away from the atmosphere for long periods of time. This process sequesters carbon in deep-sea water masses and sediments and is a crucial component in modeling Earth’s climate now and in the future.

Read the full story at Eco Magazine

North Atlantic Ocean productivity has dropped 10 percent during Industrial era

May 7, 2019 — Virtually all marine life depends on the productivity of phytoplankton — microscopic organisms that work tirelessly at the ocean’s surface to absorb the carbon dioxide that gets dissolved into the upper ocean from the atmosphere.

Through photosynthesis, these microbes break down carbon dioxide into oxygen, some of which ultimately gets released back to the atmosphere, and organic carbon, which they store until they themselves are consumed. This plankton-derived carbon fuels the rest of the marine food web, from the tiniest shrimp to giant sea turtles and humpback whales.

Now, scientists at MIT, Woods Hole Oceanographic Institution (WHOI), and elsewhere have found evidence that phytoplankton’s productivity is declining steadily in the North Atlantic, one of the world’s most productive marine basins.

In a paper appearing today in Nature, the researchers report that phytoplankton’s productivity in this important region has gone down around 10 percent since the mid-19th century and the start of the Industrial era. This decline coincides with steadily rising surface temperatures over the same period of time.

Matthew Osman, the paper’s lead author and a graduate student in MIT’s Department of Earth, Atmospheric, and Planetary Sciences and the MIT/WHOI Joint Program in Oceanography, says there are indications that phytoplankton’s productivity may decline further as temperatures continue to rise as a result of human-induced climate change.

“It’s a significant enough decine that we should be concerned,” Osman says. “The amount of productivity in the oceans roughly scales with how much phytoplankton you have. So this translates to 10 percent of the marine food base in this region that’s been lost over the industrial era. If we have a growing population but a decreasing food base, at some point we’re likely going to feel the effects of that decline.”

Osman and his colleagues looked for trends in phytoplankton’s productivity using the molecular compound methanesulfonic acid, or MSA. When phytoplankton expand into large blooms, certain microbes emit dimethylsulfide, or DMS, an aerosol that is lofted into the atmosphere and eventually breaks down as either sulfate aerosol, or MSA, which is then deposited on sea or land surfaces by winds.

Read the full story at MIT News

WHOI Scientists Studying Phytoplankton to Improve Satellite Operations in Space

November 26, 2018 — WOODS HOLE, MASS. – Researchers from Woods Hole are working to improve the quality of data collected by satellites over 500 miles above the ocean.

The goal is to determine how microscopic algae, also known as phytoplankton, absorb and scatter light, and how the colors of the phytoplankton can be better identified and measured.

For the next three years, researchers from NOAA Fisheries and colleagues at the University of Rhode Island, NOAA’s National Environmental Satellite, Data and Information Service, and Woods Hole Oceanographic Institution will look into the ocean to help improve the quality of data collected by satellites more than 500 miles above.

Read the full story at CapeCod.com

Melting ice poses fleeting ecological advantage but sustained global threat, Stanford scientist says

August 31, 2018 — From collecting field samples inside the ocean’s frozen ice pack to analyzing satellite images in the comfort of his Stanford office, Kevin Arrigo has been trying to figure out how the world’s rapidly thinning ice impacts polar food chains. Arrigo, a professor of Earth system science at Stanford School of Earth, Energy & Environmental Sciences, found that while melting ice threatens to amplify environmental issues globally, ice sheet retreat can provide much-needed food in local ecosystems.

Through this work, Arrigo discovered that thinning ice at the poles can alleviate polar food deserts by extending phytoplankton blooms. However, the silver lining associated with melting ice cannot make up for imminent threats, such as rising sea levels, associated with unchecked glacial shrinkage.

Arrigo, who is also the Donald and Donald M. Steel Professor in Earth Sciences, spoke with Stanford Report about his work on polar phytoplankton blooms and discussed whether recent news about sea ice breaking up suggests we’ve reached a tipping point.

What have you learned about how glacial melt impacts food chains in the extreme environments of the poles?

It turns out that when glaciers form, they accumulate particles and dust that contain essential nutrients like iron, on which all living things depend for survival. As glaciers melt, they add nutrients to the ocean and fertilize the local ecosystem. In Greenland and Antarctica, the ocean is short on iron, so melting glaciers make up for the lack of iron.

Read the full story at Stanford News

 

How Whale Poop Could Counter Calls to Resume Commercial Hunting

August 29, 2018 — Before whales dive into the darkness of the deep ocean they often come to the surface and release a huge plume of fecal matter—which can be the color of over-steeped green tea or a bright orange sunset. When Joe Roman, a conservation biologist at the University of Vermont, saw one of these spectacular dumps in the mid-1990s, he got to wondering: “Is it ecologically important? Or is it a fart in a hurricane?”

Roman and other researchers have since shown whale excrement provides key nutrients that fuel the marine food chain, and that it also contributes to the ocean carbon cycle. These important roles are now influencing scientific and economic arguments for protecting whales, at a time when calls for a resumption of whaling are growing. “The scientific community is coming to understand a new value of whales: their role in maintaining healthy and productive oceans,” says Sue Fisher, a marine wildlife consultant at the nonprofit Animal Welfare Institute. “We are beginning to see governments use this rationale to justify measures to protect whales.” But as the International Whaling Commission (IWC) prepares for its biennial meeting next month, the ecological services whales provide are set to split the gathered countries—with an unknown outcome for the whales.

Whale poop’s importance is nothing to sniff at. In a 2010 study Roman’s team found whale defecation brings 23,000 metric tons of nitrogen to the surface each year in the Gulf of Maine—more than all the rivers that empty into the gulf combined. This nitrogen fertilizes the sea by sustaining microscopic plants that feed animal plankton, which in turn feeds fish and other animals including the whales themselves. Studies have found similar effects elsewhere, and with other nutrients found in whale feces. And when they migrate, whales also redistribute nutrients around the globe. By moving them from higher latitudes, Roman says, the giant mammals could be increasing productivity in some tropical waters by 15 percent.

By stimulating the growth of microscopic plants called phytoplankton, whale scat may also help limit climate change. These tiny aquatic plants remove carbon from the atmosphere and carry it deep into the ocean when they die. Research in the Southern Ocean showed the iron defecated each year by some 12,000 resident sperm whales feeds phytoplankton that store 240,000 more metric tons of carbon in the deep ocean than the whales exhale. This means that, on balance, whales help lock carbon away.

Read the full story at the Scientific American

 

Zero Dollars for Marine Mammals?

February 27, 2018 — The future of marine mammals is at risk in U.S. waters. President Trump’s proposed budget for fiscal year 2019 would eliminate the Marine Mammal Commission. With an annual operating budget of $3.4 million, which comes to just over one penny per American per year, the Marine Mammal Commission has for 45 years been assiduously developing science and policy to protect seals, sea lions, dolphins, whales, dugongs and walruses. Through the 1972 Marine Mammal Protection Act (MMPA), Congress charged the commission with providing independent oversight of marine mammal conservation policies and programs being carried out by federal regulatory agencies. Obviously, with a proposed budget of zero dollars, it would be impossible to execute the federally mandated objectives of fostering sustainable fisheries (through the Magnuson-Stevens Fishery Conservation and Management Act [MSA]) and protecting endangered species (through the Endangered Species Act [ESA]).

Marine mammals are more than just lovable creatures. They are important components of productive marine and coastal ecosystems that overall generate $97 billion of the gross domestic product. Whales function as ecosystem engineers by cycling vital nutrients between deeper and surface waters in the oceans. Without this nutrient cycling, oceans would produce less plankton and phytoplankton, which would eventually mean less fish. Also, through complex food-web interactions, marine mammals help to regulate fish populations. For example, marine-mammal–eating killer whales (often called “transient” killer whales) will eat seals, a common predator of pelagic fish—enabling fish populations to stay high. This kind of interaction is called a trophic cascade and is very common in marine ecosystems.

Serving as an independent oversight body, the commission has the critical task of assessing the scientific validity and effectiveness of research conducted to meet the federal mandates of the MMPA, ESA and MSA. If we as a country can’t even protect the charismatic species, I worry for all the less adorable parts of nature. So we need to draw a line in the sand. In this era of “fake news,” maintaining this entity to guard against encroachments to science-based policymaking on is more valuable than ever.

Read the full story at the Scientific American

 

Copepods: Cows of the Sea

October 6, 2017 — If you look very closely at a glassful of water from a bay or the ocean, you would probably be surprised by the life inside. You might see miniature crustaceans the size of the period at the end of this sentence or baby crabs and fish that spend only a short span of their lives this small. These creatures are zooplankton, aquatic animals that drift with the currents.

It’s the Little Things 

These tiny animals form the basis of the food web of estuaries, coastal waters, and oceans. Zooplankton feed on microscopic plant-like organisms called phytoplankton, which get their energy from the sun. Tiny crustacean zooplankton called “copepods” are like cows of the sea, eating the phytoplankton and converting the sun’s energy into food for higher trophic levels in the food web. Copepods are some of the most abundant animals on the planet.

Fish such as anchovies cruise through the water with their mouths wide open, filtering copepods and other zooplankton from the water. Anchovies and other planktivores (plankton-eaters) are prey for bigger animals, like tuna, sharks, marine mammals, and seabirds.

Read the full story at NOAA Fisheries GARFO

Algae bloom forces suspension of shellfishing in parts of Down East Maine

It’s the second straight year that a bloom of Pseudo-nitzschia, a phytoplankton that can carry toxic domoic acid, has forced a closure along large parts of the coast.

September 15, 2017 — A marine algae bloom that can carry a potentially deadly neurotoxin has forced the suspension of shellfish harvesting in parts of Down East Maine.

The state Department of Marine Resources reported Thursday that it was monitoring an active bloom of Pseudo-nitzschia, an ocean phytoplankton that carries domoic acid, a toxin that can cause sickness, memory loss and brain damage in humans. It’s the second year in a row that a toxic Pseudo-nitzschia bloom has halted harvesting of mussels, clams and oysters along large parts of the coast.

Before 2016, there was no record of a toxic bloom of this type in the Gulf of Maine.

The department’s public health section found levels of domoic acid that exceeded health standards in shellfish tested between Mount Desert Island and Gouldsboro. That area has been closed to harvesting and the department enacted a precautionary closure from Deer Isle to Machiasport, almost a third of Maine’s coastline.

Department spokesman Jeff Nichols said officials were monitoring the situation closely. There is no indication that contaminated shellfish have made their way to consumers, he said.

“It is impossible to determine at this point if the concentrations of domoic acid will increase in other areas,” Nichols said. “But we know that the phytoplankton that produces it grows rapidly, so we are carefully monitoring the entire coast and will be able to rapidly detect harmful levels of domoic acid and take action to protect the health of Maine’s shellfish consumers.”

Read the full story at the Portland Press Herald

From tiny phytoplankton to massive tuna: How climate change will affect energy flows in ocean ecosystems

January 24, 2017 — Phytoplankton are the foundation of ocean life, providing the energy that supports nearly all marine species. Levels of phytoplankton in an ocean area may seem like a good predictor for the amount of fish that can be caught there, but a new study by Nereus Program researchers finds that this relationship is not so straightforward.

“Using measurements of phytoplankton growth at the base of the food web to estimate the potential fish catch for different parts of the ocean has long been a dream of oceanographers,” says author Ryan Rykaczewski, Assistant Professor at University of South Carolina and Nereus Program Alumnus. “We know that these two quantities must be related, but there are several steps in the food chain that complicate the conversion of phytoplankton growth to fish growth.”

Published today in PNAS, the study uses a mathematical model to explore the processes that mediate the transfer of energy from the base of the food web to fish. The authors found that there are large regional differences in fish catch because of how surface ocean and bottom ecosystems channel energy sources.

“Coastal systems where large amounts of nutrients critical for phytoplankton growth are ‘upwelled’ from deep waters via currents make a contribution to global fish catch that far exceeds what one would expect from phytoplankton production alone,” says lead author Charles Stock, Research Oceanographer at NOAA/Geophysical Fluid Dynamics Laboratory and Nereus Program Principal Investigator.

Read the full story at Phys.org