Tuesday, August 10, 2021

USA PRISON NATION

Crowding in prisons increases inmates’ risk for COVID-19 infections

COVID MAKES US POLITICAL PRISONERS







Policy changes could help minimize this threat

Peer-Reviewed Publication

MASSACHUSETTS GENERAL HOSPITAL

BOSTON – Crowding in prisons dramatically increases the risk for COVID-19 infections among inmates, according to a new study by researchers at Massachusetts General Hospital (MGH). The authors of the study, published in JAMA Internal Medicine, argue that policy changes are necessary to protect the vulnerable population of incarcerated men and women.

Earlier studies found that the incidence of COVID-19 infection is significantly higher in prisons than in the general population, but the degree to which crowding contributed to the problem was unknown. The senior author of the JAMA Internal Medicine study, MGH infectious diseases physician Amir Mohareb, MD, has worked on a pro bono basis with several advocacy groups working to ensure that infection control measures are implemented in prisons during the coronavirus pandemic. One group he advised, Prisoners’ Legal Services of Massachusetts, was suing the state’s Department of Correction over its practices. Mohareb and his colleagues analyzed a trove of data in Massachusetts that allowed them to examine more closely what’s driving the high incidence of COVID-19 in prisons.

One element the data lacked was detailed information about each individual inmate who became ill, which would have allowed Mohareb and his team to study the characteristics of who got COVID-19 and who didn’t. However, they had other critical data, including weekly reports on the number of positive COVID-19 tests at 14 Massachusetts state prisons, the population of each prison, and the number of inmates the facility was designed to hold (known as design capacity). “So we asked, What are characteristics of these facilities that might lead to more COVID-19 transmission?” says Mohareb, who is also a researcher at MGH’s Medical Practice Evaluation Center.

Their analysis found that crowding at the facilities varied greatly during the observation period, with the population at some dropping as low as 25 percent of design capacity, while others were extremely crowded, reaching up to 155 percent of design capacity. Mohareb and his colleagues found that as facilities became more crowded, the threat to inmates rose: Every increase of 10 percentage points in a prison population relative to the facility’s design capacity raised the risk of getting infected with COVID-19 by 14 percent. As Mohareb notes, that means a facility doesn’t have to be exceeding its design capacity to increase the danger for inmates, since a prison that’s operating at 80 percent capacity is riskier than one at 70 percent capacity. “We may need to have stricter thresholds for where we draw the line on how crowded a facility can be,” he says.

To study the effect of crowding another way, Mohareb’s team calculated the percentage of inmates in each prison who were housed in single cells during each week of the observation period. They found that every 10-percentage-point increase in the proportion of inmates living in single cells reduced the risk of COVID-19 infection in that prison by 18 percent.

Similar to other studies, this investigation found that inmates in prisons have a significantly greater risk—more than sixfold—for becoming infected with COVID-19 compared to the general public. But in a novel finding, Mohareb and colleagues showed that infection rates in prisons tended to reflect those of their surrounding communities. “We found a very close association,” says Mohareb. When numbers of COVID-19 cases were low in Massachusetts during the summer of 2020, they tended to be low in prisons, too. And as numbers spiked in many communities late last year, they also soared in local prisons. “Prisons are intricately linked to their surrounding communities,” says Mohareb, noting that greater attention to infection control (through vaccination and routine testing) among guards, support staff, vendors, and others who come and go from these facilities is essential.

While COVID-19 vaccination became available to inmates in Massachusetts state prisons earlier this year, it is optional; what’s more, news reports indicate that a significant portion of prison workers remain unvaccinated. Mohareb and his coauthors argue that policymakers should strongly consider decarceration—releasing prisoners deemed to be at low risk for reoffending—as a way to lower the risk for COVID-19 in prisons. “It was the almost universal opinion of experts in public health, infectious disease and epidemiology from the start of the pandemic that prisons were going to be places of immense suffering unless inmates were released in a coordinated manner,” says Mohareb. “And that really didn’t happen.”

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Mohareb is also an instructor in Medicine at Harvard Medical School (HMS). Abigail I. Leibowitz, the first author of the paper, completed this work while earning a master’s degree in public health at the Harvard T.H. Chan School of Public Health and is currently a medical student at the University of Colorado. Other authors include MGH infectious disease physician Mark Siedner, MD, MPH, an associate professor of Medicine at HMS, and MGH psychiatrist Alexander C. Tsai, MD, PhD, an associate professor of Psychiatry at HMS.

Support for this work was provided by the National Institutes of Health and the Sullivan Family Foundation.

About the Massachusetts General Hospital
Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The Mass General Research Institute conducts the largest hospital-based research program in the nation, with annual research operations of more than $1 billion and comprises more than 9,500 researchers working across more than 30 institutes, centers and departments. In August 2021, Mass General was named #5 in the U.S. News & World Report list of "America’s Best Hospitals."

How society’s inequalities showed up in COVID outcomes

Peer-Reviewed Publication

UNIVERSITY OF UTAH

COVID-19 rates by per capita income levels 

IMAGE: COVID-19 CASES FOR EACH PER CAPITA INCOME, ZIP CODE GROUP OF SALT LAKE COUNTY, UTAH (USA) BETWEEN 17 FEBRUARY AND 12 JUNE 2020. THE DASHED VERTICAL LINES SHOW THE START (BLUE) AND END (RED) OF LOCKDOWN DIRECTIVES. THE COLOR SCALE RANGES FROM RED (LOWEST INCOME TO HIGHEST INCOME). view more 

CREDIT: DANIEL MENDOZA

Racial minorities comprise around a quarter of Utah’s population but represent a third of COVID-19 cases in the state. A similar story has played out across the country. Why have racial minorities been unequally affected by the COVID-19 pandemic?

Researchers are still working out the answer to this question, but a new study from University of Utah researchers including Daniel Mendoza and Tabitha Benney explores the hypothesis that variation in income and occupational status, on a neighborhood-by-neighborhood scale, may be the reason. During the 2020 lockdowns, residents of affluent areas in Salt Lake County, Utah were able to stay at home more than residents of the least affluent zip codes, suggesting that the “essential worker” occupations of the least-affluent areas, which are also the highest minority populations, placed them at greater risk for contracting COVID-19. Subsequently, the least-affluent zip codes experienced nearly ten times the COVID incidence rate of affluent areas.

“We were shocked at the nearly tenfold difference in contagion rate increase when comparing the groups we had defined,” Mendoza says. “I think it was a very sobering moment when we realized how deep the disparities truly were in our own backyard.”

The study is published in the journal COVID.

Salt Lake County’s disparities 

Two factors make Salt Lake County an ideal site for exploring the link between inequality and COVID-19 infection. First, says Benney, an associate professor of political science, a dense network of traffic sensors produces extraordinarily detailed traffic and mobility data, organized by zip code. Pair that with a similarly detailed level of COVID-19 incidence rates and demographic, occupational and income data, and a high-resolution picture emerges.

Second, says Mendoza, a research assistant professor in the Department of Atmospheric Sciences and visiting assistant professor in the Department of City & Metropolitan Planning, Salt Lake County exhibits “strongly marked socioeconomic disparities. The substantial differences in race, income and occupation are very clear and provide a strong basis for inequality analysis.”

The divide in Salt Lake County roughly follows the I-15 freeway, which separates the county into east and west sides. The east side has a higher per capita income and percentage of white-collar workers. The divide isn’t strictly racial, however, with a more diverse northeast and less diverse southwest quadrant of the valley.

But with COVID-19 overlain onto this socioeconomic landscape, a pattern emerged.

“The first time our team crunched the numbers,” Benney says, “we were all dismayed to see how well income and occupation related to COVID incidence rates.”

What is structural inequality?

How does income and occupation relate to race? The researchers explored that question through the lens of structural inequality, which is a system of privilege in institutions and policies that place people on an unequal starting footing in society. This inequality, the researchers write, “create[s] relational patterns that effectively socialize and dictate how individuals see the world and their place in it. Inequality is considered structural when policies produced by the system keep some groups from getting ahead, regardless of their actions.”

In the first few months of the COVID-19 pandemic, as white-collar office workers and others stayed home, those deemed ‘essential’ workers still journeyed out to keep hospitals running, grocery store shelves stocked and packages moving around the country. In this case, the structural inequalities at work would be those that placed racial minorities disproportionately into lower-income occupations, and thus disproportionately into the category of blue-collar worker least likely to be able to stay home during the initial lockdown.

“The true front-line workers were far more varied than expected,” Benney says. “Medical workers are the heroes for sure, but janitors, repair people and folks that kept our homes and our families healthy throughout the pandemic were, and may again, be facing greater risks due to their starting point in life and the occupation they have today.”

The evidence for the unequal effect of lockdowns on different occupations and incomes comes from traffic data collected between February and June 2020 – before, during and after the main lockdown phase of the pandemic. Traffic decreased in zip codes with high percentages of high-income, white-collar and white residents by up to 50%. But in the least affluent zip codes, traffic decreased by only around 15%.

Statistical correlations linked those traffic patterns to income, occupation and, eventually, to COVID-19 outcomes.

“Income and occupation go hand in hand much more so than race and either of the variables,” says Mendoza, who also holds appointments as an adjunct assistant professor in the Pulmonary Division at the School of Medicine and as a senior scientist at the NEXUS Institute. In a place like Salt Lake County, structural inequalities can lead to income and occupational divides falling along racial lines.

Benney says that policies such as lockdowns, which expose some populations to higher disease risk, need to be better designed and implemented in future waves of the current pandemic and beyond. “In this case, because more affluent communities were more likely to stay home under the Stay-Home-Stay-Safe Directive in Utah, this behavior appears to have shifted the disease risk away from the wealthiest, most white, and white-collar workers, who were already more likely to rebound from a crisis,” she says. While Utahns benefitted overall from the directive, she adds, designing this policy with low income, essential workers in mind may help prevent the spread of disease, improve outcomes for vulnerable populations, and create a more resilient society overall.

Facing successive waves

Since the end of the study period in June 2020, the COVID-19 pandemic has continued with a surge in winter 2020-21, the rollout of vaccines and the growing impact of the Delta variant. Both Mendoza and Benney emphasize the need for policymakers to consider vulnerable populations, including those from low-income zip codes, in crafting a pandemic response.

“Frankly, we should be showing our support for these people by masking up in public, getting vaccinated, and looking out for our community in any way we can,” Benney says.

“Our hope is that our research provides insight into the most vulnerable and affected groups and we can pay attention to their specific needs and take care of them as they take care of the rest of us,” Mendoza adds.

Find the full study here.

Geography of inequality in Salt Lake County (IMAGE)

UNIVERSITY OF UTAH

 

Inspired by barnacles, medical glue stops bleeding in seconds


Peer-Reviewed Publication

MAYO CLINIC

Mayo Clinic researchers and colleagues at Massachusetts Institute of Technology (MIT) have developed a rapid-sealing paste that can stop bleeding organs independent of clotting. The details are published in Nature Biomedical Engineering.

The inspiration for this paste? Barnacles.

Barnacles are those sea animals that adhere to rocks, the bottom of ships and large fish with the aim of staying in place despite wet conditions and variable surfaces. They're successful because they exude a type of oil matrix that cleans the surface and repels moisture. Then they follow up with a protein that cross-links them with the molecules of the surface. That two-step process is what happens when the sealing paste is applied to organs or tissues.

Historically, surgeons would use a type of material that would speed up coagulation and form a clot to stop the bleeding. In the fastest cases, that would still take several minutes. In preclinical studies, this research team has shown the paste to stop bleeding in as little as 15 seconds, even before clotting has begun.

"Our data show how the paste achieves rapid hemostasis in a coagulation-independent fashion. The resulting tissue seal can withstand even high arterial pressures," says Christoph Nabzdyk, M.D., a Mayo Clinic cardiac anesthesiologist and critical care physician. "We think the paste may be useful in stemming severe bleeding, including in internal organs, and in patients with clotting disorders or on blood thinners. This might become useful for the care of military and civilian trauma victims." Dr. Nabzdyk is co-senior lead author of the study.

The paste consists of an injectable material that consists of a water-repelling oil matrix and bioadhesive microparticles. It's the microparticles that link to each other and the surface of the tissue after the oil has provided a clean place to connect. The biomaterial slowly resorbs over a period of weeks.

The research was supported by MIT's Deshpande Center, National Institutes of Health, National Science Foundation, Army Research Office, The Zoll Foundation, and the Samsung Scholarship. The technology is protected by a shared patent between MIT and Mayo Clinic.

Co-authors are Hyunwoo Yuk, Ph.D.; Jingjing Wu, Ph.D.; Xinyu Mao, Ph.D.; Claudia Varela; Ellen Roche, Ph.D.; and Xuanhe Zhao, Ph.D., of MIT, and Tiffany Sarrafian Griffiths, D.V.M., Ph.D., and Leigh Griffiths, Ph.D., of Mayo Clinic.

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About Mayo Clinic
Mayo Clinic is a nonprofit organization committed to innovation in clinical practice, education and research, and providing compassion, expertise and answers to everyone who needs healing. Visit the Mayo Clinic News Network for additional Mayo Clinic news. For information on COVID-19, including Mayo Clinic's Coronavirus Map tracking tool, which has 14-day forecasting on COVID-19 trends, visit the Mayo Clinic COVID-19 Resource Center.

Media contact:

Bob Nellis, Mayo Clinic Public Affairs, newsbureau@mayo.edu

 

Undersea rocks yield earthquake clues


University of Delaware study of ocean rocks informs earthquake science

Peer-Reviewed Publication

UNIVERSITY OF DELAWARE

Undersea rocks 

IMAGE: JESSICA WARREN, UNIVERSITY OF DELAWARE ASSOCIATE PROFESSOR OF GEOLOGICAL SCIENCES, ABOARD THE RESEARCH VESSEL ATLANTIS ON A SCIENTIFIC MISSION TO COLLECT GEOLOGICAL SAMPLES FROM THE EAST PACIFIC RISE, AN UNDERSEA OCEAN RIDGE WHERE HUGE SLABS OF EARTH’S CRUST ARE MOVING APART. view more 

CREDIT: PHOTOS BY THOMAS MORROW

Earthquakes shake and rattle the world every day. The U.S. Geological Survey (USGS) has estimated the number of earthquakes at some half a million a year, with some 100,000 that can be felt, and about 100 that cause damage. Some of these powerful temblors have devastated nations, cutting short thousands of lives and costing billions of dollars for economic recovery.

When will the next big earthquake occur? Answering that question has teams of scientists monitoring areas such as California’s San Andreas Fault and Turkey’s North Anatolian Fault. But these seismically active areas on land, at the boundaries of tectonic plates, are not the only places of intense study. Jessica Warren, associate professor of geological sciences at the University of Delaware, is exploring the middle of the ocean where earthquakes with a magnitude 6 on the Richter scale routinely occur, and what she is finding may help scientists predict earthquakes on land.

UDaily connected with Warren to learn more about her most recent study, which published in Nature Geoscience on Aug. 5, 2021.

Q. How did you get started on this research?

Warren: This work grew out of a previous study with seafloor rocks and involved my colleagues Arjun Kohli, who is now a research scientist at Stanford University, Monica Wolfson-Schwehr, who is now a research assistant professor at the Center for Coastal and Ocean Mapping, and Cécile Prigent, a former postdoc in my group who is now a professor at the University of Paris. This interesting group of people had all different areas of expertise to bring to the project. The National Science Foundation provided funding support.

Q: What kinds of rocks did you study and how did you get them? 

Warren: The rocks came from big fault structures underwater that are on par with the San Andreas Fault. It’s costly to get them because they are so far out at sea and it takes specialized equipment. At the end of 2019, we were in a research vessel in the Pacific Ocean above one of these faults on the East Pacific Rise, pulling buckets along the seafloor to collect samples. Most of the samples, however, had been sitting around in various collections — some were collected over 40 years ago from the seafloor. 

Q: Could you describe the rocks a bit? 

Warren: Underwater ocean ridges are areas of volcanic activity where magma from deep within Earth’s crust erupts and then cools and solidifies. The faults that we look at cut across these ocean ridges, creating steps in the ridge system. The top layer of rock on these ridges is basalt, a black, fine-grained rock rich in magnesium and iron, which is underlain by coarser-grained gabbro, and below it is peridotite, which is often dark green due to the quantity of the mineral olivine — another name for the gemstone peridot — that it contains. 

As you go deeper, rocks in the crust actually flow, like glaciers flow. This occurs at 4 miles deep in the Pacific Ocean floor, and 10 miles deep in the seafloor of the Atlantic Ocean, which is colder. The rocks you see in the fault at that point are mylonites — they are dark gray, stretched-out, deformed rocks — some call them Silly Putty. They can flow much faster than the normal rocks because they are super fine-grained (atoms in the rock move around faster when the grains are smaller). They are absolutely beautiful rocks!

Q: What do the rocks tell you about earthquakes? 

Warren: The big finding we have made is that these faults, or cracks, have a lot of seawater going down into them very deep — more than 10 miles below the seafloor, which is very deep. When water gets into the rock, it reacts with it. This seawater infiltration is a weakening force, so the rock can flow almost as fast as it can slip.  

Earthquakes are run-away slip events that occur as rocks slide past each other. We found that seawater infiltration causes the crystallization of tiny grains of minerals and these allow the rock to creep along instead of having a run-away slip event.

Q. Could you draw on this finding to stop an earthquake from happening on land?

Warren: There’s no way to stop large earthquakes from occurring. But it would improve our ability to predict – by understanding the properties – what gives us rock creep vs. a sharp slip. There is also a creeping segment of the San Andreas fault. We can’t make the rest of the fault like that. But we could better predict how and when these various fault systems are going to fail. 

Q. What will happen to the information you’ve developed, and what’s up next?

Warren: You have to know the rock properties to understand what happens in fault zones and earthquakes. We have done modeling work that is more a way to test and extrapolate how rocks deform against each other. We have done a lot of straightforward calculations validating the strength of the rocks. We now need more direct observations of the faults on the seafloor itself. The submersible Alvin would be one of the ideal vehicles for doing this. That would contribute to our understanding of the seismicity of certain patches versus other patches that sort of stop it. 

Q. What led you into this work? 

Warren: I fell in love with geology through field work in college, and then I fell in love with going to sea to do field work in graduate school. I also love looking at samples in the lab, seeing the textures and uncovering the history of the rock and what it’s telling us about the Earth. 

Disclaimer: AAAS and

 

Scientists explore mineral-rich seafloor and DDT dump sites; discover new methane seep, whale fall


Business Announcement

SCHMIDT OCEAN INSTITUTE

DDTBarrel2-20210804 

IMAGE: A BARREL THOUGHT TO CONTAIN DDT WASTE PRODUCTS RESTS ON THE BOTTOM OF THE OCEAN FLOOR OFF OF THE COAST OF LOS ANGELES. MANY OF THE BARRELS, WHICH WERE DUMPED BETWEEN 1947 AND 1982, ARE SURROUNDED BY LIGHT-COLORED BACTERIAL MATTE HALOS. THE HALOS INDICATE A CHANGE TO THE MICROBIAL COMMUNITY IN THE SEDIMENT AND THE SCIENTISTS HOPE TO LEARN WHAT BACTERIA ARE THERE AND WHAT CHEMICALS THEY ARE BREAKING DOWN. view more 

CREDIT: USE WITH CREDIT TO SCHMIDT OCEAN INSTITUTE

Marine scientists aboard Schmidt Ocean Institute's research vessel Falkor have completed a 12-day expedition off the coast of Southern California to survey the biodiversity of deep sea areas rich in minerals that are of interest to deep sea mining developers around the world. 

The expedition, which covered 5,310 square miles, explored nine deep sea sites, including the offshore site where possibly hundreds of thousands of barrels of toxic waste from the production of the insecticide DDT were dumped from 1947 to 1982.

With an underwater robot, the team of scientists from UC San Diego’s Scripps Institution of Oceanography and the United States Geological Survey collected sediment and biological samples around six barrels to understand potential ecological effects of the dump site and to determine the levels of DDT present in the ecosystem after more than 50 years. The site had been surveyed previously by scientists from UC Santa Barbara and Scripps on previous expeditions.

The goal of the Schmidt Ocean Institute expedition was to establish mineral and biological baselines in the area known as the southern California Borderland, which has  the potential for deep sea mining. The area contains rare earth marine minerals such as ferromanganese and phosphorite that are used in the manufacture of electronics, electric car batteries, solar panels, and other green technologies.

Scientists collected more than 300 samples of seafloor rocks, sediment, seawater, and marine invertebrates to better understand the ecology, mineral and microbial makeup of the relatively unexplored deep-sea system. In collecting samples, researchers also hope to evaluate the therapeutic or drug discovery potential of deep-sea microbes found in mineral-rich areas. 

“We are just beginning to understand the valuable resources of our ocean ecosystem,” said Wendy Schmidt, co-founder of Schmidt Ocean Institute. “We can’t protect what we don’t know and understand, and the human impact on our ocean over the past 75 years has had a detrimental  effect on its health and on the many ocean systems that support life on land. We expect the knowledge gained from this expedition will inform policy, management and stewardship of the deep sea, so that episodes of dumping toxic waste, such as this one, will not happen again”

The 12 expedition dives were broadcast live to the public on Schmidt Ocean Institute’s social media channels. During one of the dives to explore the DDT site, scientists discovered a whale fall--the seafloor location where the remains of a whale come to rest. Scientists also identified a new area of methane seepage. Marine biologists consider both areas a focus of specialized research because of the unique habitat they create.

“Establishing ecological baselines in the deep sea allows us to track changes over time  and better understand  the consequences of human actions,” said Chief Scientist Dr. Lisa Levin, a professor of biological oceanography at Scripps Institution of Oceanography. “The  DDT dump site provides evidence of a large human footprint in the deep ocean, but we are just starting to identify the effects on local marine communities.”

The information the team collected at the DDT barrel disposal site will be compared to animals and microbes at more distant sites in order to assess the current concentrations and effects of DDT in the region. The samples will return to Scripps Institution of Oceanography where scientists will conduct further analysis and DNA sequencing.


CAPTION

A brittle star and coral are picked up by ROV Subastian’s manipulator arm, along with the piece of deep-sea rock they are inhabiting. Taking the rock along with the accompanying organisms allows the scientists to study whether certain organisms prefer certain substrates.

 

Chiari & Glaberman to receive funding for study of endangered sea turtles


Grant and Award Announcement

GEORGE MASON UNIVERSITY

Ylenia Chiari, Assistant Professor, Biology, and Scott Glaberman, Assistant Professor/Associate Chair for Research, Environmental Science and Policy, Faculty Fellow, Potomac Environmental Research and Education Center (PEREC), are set to receive funding to study the Kemp's ridley—the most endangered sea turtle in the world.  

The researchers have two objectives for their study. 

The first is to determine whether repeated cycles of severe population decline have drastically reduced genetic variation of Kemp's ridley sea turtles. Genetic variation is one of the key predictors of whether a species will go extinct. 

The second is to determine how genetic data can inform conservation strategies and head start breeding programs. 

The unique approach of this project is that it uses turtle museum samples from the last 150 years to better understand how the history of population fluctuations in Kemp’s ridley sea turtles can be used to predict the future of this species amidst the threats of climate change, poaching, and habitat loss. 

The researchers hold that their project will transform scientific understanding of the most endangered sea turtle in the world and will represent the most comprehensive conservation genetics study of Kemp's ridley turtles to date. 

The researchers will receive $26,094 from The Eppley Foundation for Research, Inc., for this project. Funding will begin in September 2021 and will end in September 2022.  

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About George Mason University

George Mason University is Virginia's largest public research university. Located near Washington, D.C., Mason enrolls 38,000 students from 130 countries and all 50 states. Mason has grown rapidly over the last half-century and is recognized for its innovation and entrepreneurship, remarkable diversity and commitment to accessibility. Learn more at http://www.gmu.edu.

 

Salt marsh resilience compromised by crabs along tidal creek edges


A long-term study in California's Elkhorn Slough revealed the impact of superabundant crabs on salt marsh vegetation and the vulnerability of tidal creek banks to erosion

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - SANTA CRUZ

Striped Shore Crab 

IMAGE: THE STRIPED SHORE CRAB (PACHYGRAPSUS CRASSIPES) IS A SMALL CRAB FOUND ALL ALONG THE WEST COAST OF NORTH AMERICA, AND IT IS EXTREMELY ABUNDANT IN ELKHORN SLOUGH. view more 

CREDIT: K. BEHESHTI

Coastal marshes are vulnerable to erosion caused by rising seas, pounding waves, and tidal flows. In Elkhorn Slough on the Central Coast of California, these vulnerabilities are made worse by superabundant crabs found at their highest densities along the estuary’s tidal creeks, according to a new study published August 8 in Ecosphere.

The striped shore crab (Pachygrapsus crassipes) is a small crab found all along the West Coast of North America, and it is extremely abundant in Elkhorn Slough. The study demonstrated the dual role of these crabs as both consumers of salt marsh vegetation and as ecosystem engineers.

“Their burrowing weakens the creekbank edges, so that whole chunks of marsh will sometimes calve off, and by lowering biomass they are reducing the ability of marsh plants to prevent erosion,” said lead author Kathryn Beheshti, who earned her Ph.D. in ecology and evolutionary biology at UC Santa Cruz in 2021 and is currently a California Sea Grant State Fellow at the Ocean Protection Council’s Climate Change Program.

Beheshti and her coauthors conducted a five-year field experiment to assess the effects of crabs on the vegetation and sediments along eroding creekbank edges. Using fencing and traps made of empty tennis-ball cans to exclude crabs from experimental enclosures, they found that reducing crab abundance led to increased growth of salt marsh vegetation and enhanced sediment density.

The researchers also found that the number of burrows did not change over the study period, even with researchers experimentally removing crabs. The unexpected persistence of the burrows highlights the value of long-term field experiments. The experiment was maintained for five years thanks in large part to the efforts of a team of over 50 UC Santa Cruz undergraduate students and high school interns.

“Field experiments that span multiple seasons and years are rare,” said coauthor Kerstin Wasson, research coordinator of the Elkhorn Slough National Estuarine Research Reserve and an adjunct professor at UC Santa Cruz. “This work demonstrates the value of long-term studies by showing that burrows, which weaken the stability of tidal creek banks, persist despite the near absence of the crabs that build them.”

Coauthor Brent Hughes, assistant professor at Sonoma State University, noted that the crabs were most abundant in spring and summer, when the pickleweed marshes are at peak production. “This synchrony suggests that the effect of crabs as consumers is more punctuated than their more chronic effect as engineers,” he said.

Elkhorn Slough is one of the largest estuaries in California, with the largest tract of tidal salt marsh in the state outside of San Francisco Bay. It has been highly altered by human activities, however, and erosion along the edges of the tidal creeks and main channel is steadily eating away at the marsh.

“It’s a big issue, because when the marsh erodes away along the tidal creeks it’s a permanent loss,” Beheshti said.

The impacts of crabs on marsh biomass and soil structure near tidal creek banks are likely to make the marsh less resilient to erosion and sea-level rise, presenting a unique challenge to managers. Restoring populations of crab predators, such as herons, racoons, and sea otters, may be one way to mitigate these negative effects.

“In this system, top-predator recovery is key,” said coauthor Brian Silliman, distinguished professor at Duke University.

This collaborative study brought together marsh ecologists from both the East and West Coasts who have led the field in exploring how animals affect the marshes they inhabit. Over the past few decades, the U.S. East Coast has been the epicenter of studies exploring top-down effects in salt marshes, and this study is one of the few to explore such effects in a West Coast salt marsh.

“Southeastern U.S. marshes appear to be a harbinger of what’s to come for marshes along the Pacific coast, with sea-level rise amplifying the effects of what would otherwise be considered an innocuous crab,” said coauthor Christine Angelini, associate professor at University of Florida.

The authors called for similar long-term studies to be conducted in other West Coast marsh systems to determine how widespread these crab effects are. “It’d be great for contextualizing our findings,” Beheshti said. “We’d like to know if Elkhorn Slough is the canary in the coal mine, signaling yet another pathway for accelerated marsh edge loss for one of California's rarest coastal habitats.”

This work was supported in part by grants from the David H. Smith Conservation Research Fellowship, the Myers Ocean Trust, and Friends of Long Marine Laboratory.

Ross earns NSF CAREER award to study fresh, saltwater mixing in estuaries


Grant and Award Announcement

UNIVERSITY OF MAINE

The way fresh and seawater mix in an estuary influences its water circulation, physics and quality, which affect ecosystems and aquaculture. Scientists understand the dynamics of the process in estuaries with simple topographies, but Lauren Ross seeks to better understand them in more complex ones, like the Penobscot River Estuary in eastern Maine. 

The National Science Foundation awarded Ross, an assistant professor of hydraulics and water resources engineering at the University of Maine, a more than $600,000 CAREER Award to improve scientists’ understanding of how estuary shape, river discharge and tides influence fresh and saltwater mixing. The award is the organization’s most prestigious for early career faculty.

Salt water from the sea blends with fresh water from rivers at the mouths of estuaries, which forms a brackish water that flows back into the sea. Ross says the extent of the mixing process can influence how long particles, such as contaminants, excess nutrients and larvae, remain in an estuary, as well whether it experiences hypoxia — or low oxygen levels. Tides can increase the amount of mixing, further affecting the movement of waterborne materials.  

Previous studies into the dynamics of fresh and saltwater blending focus primarily on partially-mixed estuaries, meaning they experience moderate freshwater inflow from rivers, and estuaries with basic dimensions, Ross says. As a result, current research provides less insight into estuaries with complicated topographies like irregular and fluctuating depth and width, headlands and constructions, and estuaries that have relatively large or small freshwater inputs from rivers, all of which can create more or less mixing.

Ross, therefore, will use on-site data and numerical model simulations to quantify the mixing processes in more complex estuaries from across the world. Her research will encompass the Penobscot River Estuary, which experiences moderate river input and tides; the Reloncavi Fjord in the Chilean Patagonia, which has large river input and small tides, and the Gironde Estuary in southwest France, which has large river input and tides. Exploring a variety of estuaries can provide insight into how tides, freshwater input and topography affect the mixing process.

“The interface and exchange of ocean and river water in estuaries greatly influences the hydrodynamics, circulation patterns and transport of material, but we don’t yet fully understand the exchange process,” she says. “I aim to better understand this process and in turn use it to help negotiate and implement pollution and seafood management strategies in estuaries in complicated topographic settings, partly by refining approaches for determining timescales for transport of water borne materials like pollutants, larvae, and harmful algal blooms.” 

Ross has dedicated much of her scientific career toward investigating the physics of estuaries, particularly its flow and the mechanisms that influence it. 

Her recently published research includes quantifying the dynamics of the Jordan River in Down East Maine to understand how they affect particle movement, and creating a framework for reviewing tidal turbine placement in estuaries. Ross also is working on developing a tool to predict how biotoxins from algal blooms travel through estuarine and coastal waters. She has conducted previous studies in the Penobscot River Estuary, Reloncavi Fjord and Gironde Estuary, and plans to use data from them for her CAREER Award project. 

Ross has already created models for the three estuaries, which will produce simulations for her and two graduate students to analyze for their results. 

The ones for the Reloncavi Fjord and Penobscot River Estuary, however, need validation using on-site data. 

One graduate student will help verify the accuracy of the Penobscot model by tasking high school students from Maine Ocean School in Searsport with collecting data from 12 spots in the estuary continually over the course of the five-year-long project. The other graduate student will use publicly available data for the Reloncavi Fjord to validate their model. 

After completing her study, Ross will create and share lesson plans about her findings for high school math and science classes, which she says should teach students about “the differences among the three estuaries, explain simple tidal and volume conservation theory and introduce data visualization tools.” 

Ross also plans on sharing the findings from her research on the Penobscot River Estuary in a yearly Summer Lecture Series at the UMaine Hutchinson Center in Belfast, Maine starting in 2022.

“Estuarine ecosystems are important to us commercially and recreationally, but they are also very delicate ecosystems,” Ross says. “I believe it is important to educate our community and the next generation of scientists and coastal managers on these vital coastal environments as early as possible.”