News
New Method Improves Blue Carbon Measurements in Coastal Wetlands

carbon in flooded coastal sediments, a gap that could influence global carbon storage
estimates and assessments of marsh resilience. (URI Photo courtesy of Erin Peck)
KINGSTON, R.I. – Dec. 4, 2025 – Coastal wetlands, like salt marshes, keep pace with
sea-level rise by accumulating sediment and burying organic carbon in their soils, an
important natural process that also helps sequester carbon. Accurately measuring this
stored carbon is essential for understanding marsh resilience and informing blue carbon
strategies.
But a new study led by Erin Peck, an assistant professor at the University of Rhode Island’s Graduate School of Oceanography, and Serina Wittyngham, an assistant professor at the University of North Florida, identifies a fundamental limitation in a widely-used method for measuring organic carbon in flooded coastal sediments. This gap has implications for global estimates of carbon storage and marsh resilience.
Traditional blue carbon methods assume that all measured organic matter contributes to long-term carbon storage and sediment volume. The new study shows this isn’t always the case. Some organic matter is dissolved in sediment porewater, while other portions adhere loosely to sediment particles or are bound within the internal structure of clay minerals. These forms of organic matter may not contribute to sediment volume, accretion, or marsh resilience.
By examining more than 23,000 tidal marsh sediment samples across multiple marsh systems, Peck, Wittyngham, and their collaborators demonstrated that this overlooked fraction of “volumeless” organic matter can lead to overestimates of both carbon storage and marsh elevation gains. Recognizing this nuance allows scientists to refine their estimates of carbon sequestration and resilience, ensuring that restoration planning, carbon accounting, and predictive modeling are based on the most accurate information possible.

from a salt marsh. (Photo courtesy of Sophia Wensman)
The researchers’ findings were published recently in a peer-reviewed article in the journal Limnology and Oceanography Letters.
“This discovery came out of a simple question,” said Peck. “Serina and I were working on a project, trying to convert different components of a sediment core from mass to volume, and became frustrated that we couldn’t get the math to work out. Eventually, we realized that maybe we were missing something obvious—that not all our masses contribute to volume.”
“We started this ‘thought experiment’ by reflecting on sugar dissolved in water: you can dissolve a large mass of sugar without changing the volume of the water,” Wittyngham said. “This same concept applies to dissolved organic matter in sediments.”
Interdisciplinary Collaboration
Peck, a geologist, and Wittyngham, an ecologist, emphasized the value of cross-disciplinary collaboration while conducting their research, noting that working together helped them move beyond the standard methods typically used in their individual fields.
“While writing about our research, we reviewed our calculations with modelers, biogeochemists, and a range of other researchers,” said Wittyngham. “This issue could affect anyone working with blue carbon across ecosystems, and we wanted to make sure we fully understood its implications.”
Refining Blue Carbon Science
The researchers hope their findings will serve as a starting point for broader collaboration within the blue carbon community. They aim to develop correction factors to adjust previous measurements for volumeless organic matter, addressing this methodological limitation while preserving the value of data already collected.
Peck and Wittyngham emphasized the importance of working with the global scientific community to refine these methods while keeping data accessible. “We’re excited to collaborate with colleagues worldwide to improve blue carbon measurements and ensure the method remains open and usable for everyone,” Peck said.
By identifying and addressing this methodological gap, the study offers a constructive pathway to strengthen blue carbon science, improve coastal management decisions, and enhance predictions of marsh resilience in the face of sea level rise.
This story was written by Mackensie duPont Crowley, digital communications coordinator in URI’s Graduate School of Oceanography.
Issue 132 - May 2026
SeaKeepers Welcomes Dr. Mark Luther as First Scientist Chairman, Marking a New Era for Ocean Research
The International SeaKeepers Society marks a historic milestone, appointing Dr. Mark Luther of the University of South Florida as its first scientist Chairman, succeeding Jay Wade and signaling a deeper scientific chapter for the yachting-led conservation organization.

April 10, 2026. The Board of Directors of The International SeaKeepers Society has announced a leadership transition, extending its deepest gratitude to outgoing Chairman Jay Wade and welcoming Dr. Mark Luther as the organization’s first scientist Chairman, a historic milestone for the ocean conservation NGO.
During his tenure, Jay Wade provided steady, thoughtful leadership, guiding the organization through a period of growth while remaining anchored in SeaKeepers’ mission to advance oceanographic research, conservation, and marine education. A passionate advocate for the yachting and boating community, Wade championed a vision of transforming private vessels into platforms for scientific discovery, expanding the organization’s global reach and strengthening its role as a bridge between ocean science and the maritime industry.
A first scientist Chairman for SeaKeepers
Dr. Mark Luther brings decades of expertise in physical oceanography and maritime systems, alongside a lifelong connection to the water. He earned his Ph.D. in Physical Oceanography from the University of North Carolina at Chapel Hill and currently serves as Professor and Director of the Center for Maritime and Port Studies at the University of South Florida’s College of Marine Science.
With over 30 years of experience supporting oceanographic observation systems, including longstanding work with NOAA’s Tampa Bay Physical Oceanographic Real-Time System, Dr. Luther has been at the forefront of integrating science with real-world maritime operations. His leadership extends across key regional and federal committees, where he collaborates closely with the U.S. Coast Guard, port authorities, and maritime stakeholders to address environmental challenges tied to marine transportation.
A dedicated member of the SeaKeepers community, Dr. Luther has served as Chair of the organization’s Scientific Advisory Council, helping to guide and elevate its scientific initiatives. He is also an avid boater and U.S. Coast Guard-licensed captain, having spent more than four decades navigating the waters of Tampa Bay and Florida’s west coast.
“With years of dedicated service to SeaKeepers, Mark brings a deep understanding of our mission to this role. It is exciting to see him step into the position of Chairman and help guide the organization forward.”
Jay Wade, outgoing Chairman, The International SeaKeepers Society
Dr. Luther’s appointment signals an exciting new chapter for SeaKeepers, one that deepens the organization’s scientific leadership while continuing to engage the global fleet in meaningful ocean research, education, and conservation.
About The International SeaKeepers Society. The International SeaKeepers Society works with the yachting community to take part in research, conservation, and educational efforts that advance the health of the ocean. Learn more at seakeepers.org or @seakeepers on social.
Adapted from a press release issued by The International SeaKeepers Society on April 10, 2026.
Issue 132 - May 2026
Falmouth Harbour Trials the World’s First All-Concrete Pontoon Float to Replace EPS in Marinas
Falmouth Harbour is trialling the world’s first all-concrete marina pontoon, designed by Cornwall-based ScaffFloat, as a recyclable alternative to Expanded Polystyrene floats and a step toward cutting marine microplastic pollution.
Falmouth, Cornwall, UK. Falmouth Harbour is trialling the world’s first all-concrete marina pontoon float, designed and built by the team at ScaffFloat in neighbouring Penryn, in a first step to removing all Expanded Polystyrene (EPS) floats from its leisure and commercial operations.
The Harbour has pledged to move away from EPS products in the light of mounting evidence that polystyrene microplastics in the world’s oceans inflict serious damage on the marine environment and life within it. Polystyrene, globally used for its lightness and buoyancy, is made from fossil fuels, is virtually un-decomposable, and when it breaks down into microplastics can be ingested by marine life with devastating consequences.
“The amount of broken-up polystyrene around our creeks and rivers, particularly after this year’s storms, is awful to see and very hard to clean up without damaging the delicate ecology of our shorelines. Expanded Polystyrene fragments in the marine environment pose a serious ecological concern, as seabirds, fish, turtles and other fauna mistake EPS beads for food, which can cause internal injuries or death; entering the food chain poses health risks to humans as well.”
Vicki Spooner, Environment Manager, Falmouth Harbour
Inside the Reef Float: an inert, recyclable alternative to EPS
Penryn marine company ScaffFloat Ltd has tackled the challenge of finding alternatives to traditional pontoons by inventing the “Reef Float.” Their first commercial prototype, made entirely from concrete, has been undergoing trials beneath a Falmouth Harbour pontoon. ScaffFloat developed the new product as part of a business development project that received £284,787 from the UK Government through the UK Shared Prosperity Fund as part of Cornwall’s Good Growth Programme.
The Reef Float’s buoyant core is made using ultra-low-density waterproof concrete, instead of EPS foam, and the core is then cast inside a high-strength engineered concrete skin. In the highly unlikely event that a Reef Float ever failed, the materials would simply sit inertly as stone in the marine environment, whereas a cracked-open EPS float exposes its polystyrene foam core to the marine elements.
“We replaced a failing EPS pontoon float at Falmouth Harbour with a Reef Float, where it survived all that this January’s storms could throw at it. It’s what we would expect, of course, as we’ve designed it to be strong with an ultra-long life. But it’s also completely inert in the marine environment and 100 percent recyclable, so a game-changing alternative to the EPS floats currently used all over the world.”
Toby Budd, Founder and Managing Director, ScaffFloat
Local innovation, global stage
Local MP Jayne Kirkham, checking out the new Reef Float in Falmouth, called it “exactly the kind of innovation we want to see in Cornwall: local businesses developing practical but cutting-edge solutions to global environmental challenges. Cutting polystyrene pollution from our waters while creating skilled jobs is a win for our marine environment and our economy. I’m proud to see government funding helping projects like this lead the way.”
“Falmouth Harbour has made the conscious decision to move away from EPS foam pontoons in all our operations, and it’s fantastic that our neighbours at ScaffFloat are the first company to offer a plastic-free alternative. Reef Floats are easily installed, in situ, on a rolling basis, as and when we need to replace old EPS floats, and they have a zero-cost, 100 percent recyclable end-of-life disposal. It’s another tremendous example of Cornish ingenuity, and we look forward to working with them into the future.”
Miles Carden, CEO, Falmouth Harbour
The Reef Float team has been shortlisted for the Innovation Award at Marina26 in Australia this May, with an invitation to attend and present at the biggest marina conference in the world, demonstrating what a major issue EPS has become for the marina industry and legislative authorities alike.
Australia itself lost more than 1,000 pontoons in the 2022 Queensland floods, where they broke up and created an environmental disaster known as the “White Spill,” with the ocean and beaches covered with EPS balls that were almost impossible to clear up.
Learn more. For more information on Reef Float and parent company ScaffFloat, visit scafffloat.co.uk/reeffloat. For more on Falmouth Harbour, including its wide-ranging environmental initiatives, see falmouthharbour.co.uk.
Adapted from a press release issued by Louise Midgley Communications, on behalf of ScaffFloat and Falmouth Harbour.
Conservation Photography
Little Cayman Hope Spot Shows Early Signs of Reef Recovery After the World’s Most Extreme Coral Bleaching Event
CCMI’s 2025 Healthy Reefs Report Card shows Little Cayman’s coral cover edging back to 13.4 percent, an early but unmistakable sign that the island’s reefs are beginning to recover from the world’s most extreme coral bleaching event.
Little Cayman, Cayman Islands. Marking Earth Day 2026, the Central Caribbean Marine Institute (CCMI) released its 2025 Healthy Reefs Report Card, revealing early signs of recovery and renewed hope for Little Cayman’s reefs after the most extreme coral bleaching event on record in 2023.
The summer of 2023 was the hottest ever measured, and it brought with it one of the most extensive global coral bleaching events in modern history, decimating reefs from the Caribbean to the Indo-Pacific and casting their future in doubt. CCMI’s Healthy Reefs campaign has tracked Little Cayman’s reefs since 1998, and the 2024 surveys delivered the bleakest numbers in the program’s history: coral cover had collapsed to 9.8 percent, down from 26 percent before the marine heatwave.
This year’s data tells a different story. The 2025 surveys, summarized in the new Report Card, show coral cover edging back up to 13.4 percent. The shift is not yet statistically significant, but the direction is unmistakable: recovery in Little Cayman has begun.
A site-by-site picture
Zoom in from the island-wide average and the recovery looks more layered. Twenty percent of surveyed sites posted a significant increase in coral cover between 2024 and 2025. One site, Coral City, held the line entirely through the bleaching, exhibiting no significant loss. In total, 30 percent of sites have either maintained pre-bleaching coral levels or demonstrated significant recovery this year. The remaining 70 percent show either minor, non-significant recovery or no recovery at all.
Reef recovery is rarely visible on a 12 to 24 month horizon. Corals are slow-growing animals, and even after a disturbance ends, biologists typically expect at least three years before measurable rebound, and a minimum of seven years (sometimes nearly thirty) for a reef to return to pre-bleaching baselines. Against that timeline, what CCMI is recording in 2025 is striking: the resilience built into Little Cayman, with strong protections and minimal local disturbance, appears to be doing exactly what reef science predicts it should do.
Fish populations holding the line
While coral cover is still climbing back, fish populations have continued to thrive. CCMI has documented consistent increases in fish density since 2016, with a dramatic jump in density and biomass in 2024 that held through 2025. That matters more than it might sound: herbivorous fish keep macro-algae in check, and when algae is left unchecked it can smother corals and block new recruits from settling. A healthy reef-fish community is, in many ways, what makes coral recovery possible at all.
A Hope Spot earning its name
Little Cayman is a Mission Blue Hope Spot, a designation that frames the island as a small-but-mighty example of what marine protection can look like when conservation is prioritized. Under the pressures the ocean is now under, that framing reads less like marketing copy and more like a working hypothesis the reef is steadily proving out.
The island has form here. Little Cayman’s Nassau grouper spawning aggregation rebounded from roughly 1,000 individuals to nearly 9,000 over a decade, one of the most cited recovery stories in the Caribbean. The early coral signal in the 2025 Report Card could become another chapter in that record.
The nursery, and three resilient genotypes
CCMI’s coral nursery was hit hard during the 2023 bleaching, losing close to 90 percent of its stock. Genetic work in the aftermath identified three staghorn coral genotypes that survived nearly 20 degree-heating weeks. Since 2023, those three genotypes have rebuilt the nursery from just 17 fragments to nearly 300 as of March 2026. CCMI’s nursery likely represents one of the last remaining populations of the critically endangered staghorn coral, Acropora cervicornis, in Little Cayman.
Why this matters beyond Little Cayman
Hope Spots like Little Cayman do not just protect their own waters. They function as larval source populations, exporting recruits along ocean currents to less resilient reefs downstream. In a warming ocean where many sites have lost their capacity to bounce back unaided, these pockets of resilience are increasingly the difference between regional collapse and regional recovery.
The 2025 numbers do not erase what 2023 took. Coral cover is still well below pre-heatwave levels, and the recovery is partial, uneven, and fragile. But for the first time since the bleaching, the trendline is pointing in the right direction. As CCMI puts it, research and science-based actions are critical right now to understand the ecological processes driving this resilience and to translate that understanding into management and protection.
Acknowledgments
CCMI thanks this year’s Healthy Reefs sponsors: Wheaton Precious Metals International, Foster’s Supermarket, Cayman Water, and Ugland Properties; and the Restoration program sponsors who made the work possible: The Ernest Kleinwort Charitable Trust, Artex Cayman Islands, Walkers, and Marfire.
Read the full 2025 Healthy Reefs Report Card at tinyurl.com/CCMI-25HRR and learn more about the Healthy Reefs campaign at reefresearch.org/our-work/research/healthy-reefs/.
Adapted from a press release issued by the Central Caribbean Marine Institute (CCMI), April 22, 2026. Photo credit: CCMI.
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