Study challenges theory behind N.C. blue crab decline

North Carolina State University

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In a new study, researchers from North Carolina State University compared numbers of juvenile blue crabs across three nursery habitats in Pamlico Sound, both pre- and post-fishery decline, and found that while adult populations declined and have remained low, juvenile populations remained the same during both periods. The work points to a potential population bottleneck for crabs post-nursery but pre-maturity.

The Albemarle-Pamlico Estuarine System (APES) supports the majority of North Carolina’s blue crab population and provides key nursery habitat. Larval blue crabs are released by mature female crabs from narrow inlets along the Outer Banks during the late spring, progressing through several planktonic molts in the Atlantic Ocean before returning to the estuary in the fall through a combination of wind- and storm-driven transport. The newly arrived juvenile crabs settle in near-shore habitats, like seagrass beds and shallow marsh peat habitats, along the eastern and western shores.

“These juveniles hang out in the nurseries until they’re basically big enough to pick a fight and win, then they move into the rest of the estuary,” says Erin Voigt, a Ph.D. candidate at NC State and first author of the study.

The North Carolina blue crab fishery showed a decline in blue crab populations in the early 2000s, leading to protective measures and a 50% reduction in crab fishing. However, the adult crab population hasn’t rebounded.

“The normal explanation for situations like these is recruitment overfishing, which just means that adults have been overfished to the point that they cannot produce enough young to get back to pre-collapse numbers,” Voigt says. “We wanted to determine if that was the case here.”

Voigt looked at the density of juvenile crabs – defined as having carapace widths between 2.2 and 20 millimeters – in three nursery habitats in the APES: patchy and ephemeral seagrass beds on the western shore, western shallow detrital habitats composed of marsh peat mats, and the eastern seagrass beds. She compared the densities across two time periods, 1996 – 1999, pre-fisheries decline, and 2017 – 2019, post-fisheries decline.

The comparison showed that the number of juveniles in the APES nursery habitats were the same both pre- and post-decline, although the western seagrass habitats had almost four times more crabs than the eastern one, which was traditionally considered the primary nursery habitat.

“The main takeaway here is that the decline in adult populations isn’t directly due to recruitment problems,” Voigt says. “Even if some of these juveniles are coming down from the Chesapeake or up from the Gulf populations, the numbers indicate that there should be significantly more adult crabs in the area.

“There is most likely a bottleneck we aren’t aware of that’s happening somewhere between their arrival in the habitats and reaching adulthood. If we can find that bottleneck it may help the numbers improve.”

The study appears in Fisheries Oceanography and was supported by North Carolina Sea Grant; the Southeastern Climate Adaptation Science Center; Albemarle-Pamlico National Estuarine Partnership; Curtis and Edith Munson Foundation; North Carolina Division of Marine Fisheries and the Center for Marine Sciences and Technology, NC State University. David Eggleston, professor of marine, earth and atmospheric sciences at NC State, is the corresponding author. Former NC State Ph.D. student Lisa Etherington also contributed to the work.

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Note to editors: An abstract follows.

“Long-term trends in juvenile blue crab recruitment patterns in a wind-driven estuary”

DOI: 10.1111/fog.70009

Authors: Erin Voigt, Lisa Etherington, David Eggleston, North Carolina State University
Published: Sept. 10, 2025 in Fisheries Oceanography

Abstract:
Conserving exploited marine species requires understanding population dynamics across life stages and habitats. This study analyzes juvenile blue crab (Callinectes sapidus) recruitment trends in North Carolina’s Albemarle-Pamlico Estuarine System. Juvenile densities (2.2–20 mm carapace width) were compared across three nursery habitats, western shore Ruppia maritima seagrass beds (WSG), western shallow detrital habitats (SDH), and eastern mixed-species seagrass beds (ESG), during two periods: 1996–1999 (pre-fishery decline) and 2017–2019 (post- decline). WSG consistently supported higher juvenile densities than both ESG and SDH despite its ephemeral nature and distance from larval sources. Surprisingly, juvenile densities did not differ between time periods, suggesting recruitment overfishing is unlikely. A weak stock-recruit relationship and no recruit-to-spawning stock link indicate a potential population bottleneck post-nursery but pre-maturity. Salinity significantly affected catch per unit effort, and spawning data revealed the importance of integrating environmental variability into fisheries assessments. These findings highlight the importance of conserving key nursery habitats and conducting further research into juvenile population dynamics for sustainable management.

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Journal

Fisheries Oceanography

DOI

10.1111/fog.70009 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Long-Term Trends in Juvenile Blue Crab Recruitment Patterns in a Wind-Driven Estuary

 

Advances in iron-based Fischer-Tropsch synthesis with high carbon efficiency

Dalian Institute of Chemical Physics, Chinese Academy Sciences

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Simultaneously suppressing primary CO2 formation through the stabilization of phase-pure iron carbides and secondary CO2 generation via hydrophobic surface engineering and graphene confinement has emerged as a promising strategy in iron-based Fischer-Tropsch synthesis. These approaches effectively mitigate side reactions such as the water-gas shift and CO disproportionation, enhance active phase stability, and ultimately improve carbon efficiency, reduce CO2 emissions, and promote selective formation of long-chain hydrocarbons under realistic FTS conditions.

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Credit: Chinese Journal of Catalysis

Fischer-Tropsch synthesis (FTS) is an important technology for converting carbon-rich resources such as coal, natural gas, and biomass into clean fuels and high-value chemicals through synthesis gas. Iron-based catalysts are widely used in industrial applications due to their low cost and strong adaptability, especially for syngas derived from coal or biomass with low H2/CO ratios. However, the catalytic process is complicated by frequent phase transformations among metallic iron, iron oxides, and iron carbides, which hinder mechanistic understanding and stability. Additionally, side reactions, such as CO disproportionation and the water-gas shift reactions, lead to excessive CO2 formation, significantly reducing carbon utilization efficiency.

 

Iron-based catalysts exhibit complex and dynamic phase behavior during FTS, with iron carbides generally recognized as the primary active phases. Different iron carbide phases (e.g., ε-Fe2C, χ-Fe5C2, and θ-Fe3C) demonstrate distinct catalytic performances and readily interconvert under reaction conditions, critically influencing activity and product selectivity. In situ characterization has revealed the coexistence and transformation of multiple phases during operation, underscoring the importance of precise regulation to stabilize the most catalytically favorable phase.

 

To address high CO₂ selectivity and improve carbon efficiency, three key strategies have emerged:

ⅰ. Stabilization of phase-pure iron carbides, which prevents their oxidation into less active species like Fe₃O₄ and mitigates primary CO₂ formation; ⅱ. Hydrophobic surface modification, which reduces H₂O adsorption and thereby suppresses secondary CO₂ formation from the WGS reaction; ⅲ. Graphene confinement and 2D material encapsulation, which enhances the thermal and structural stability of active phases, tunes the electronic environment, and further inhibits CO₂-generating pathways. Together, these approaches offer a comprehensive framework for enhancing the stability and catalytic performance of iron-based FTS catalysts, enabling more efficient and sustainable FTS processes with reduced CO2 emissions.

 

This review summarizes recent advances aimed at enhancing carbon efficiency in iron-based FTS catalysts. It highlights the critical role of constructing and stabilizing iron carbide active phases which critically influence catalytic activity, product selectivity, and phase dynamics under reaction conditions. Various strategies to suppress CO2 formation including promoter addition, hydrophobic surface modification, and active phase stabilization, are critically examined for their effectiveness in improving carbon utilization. Particular attention is given to the application of two-dimensional materials, such as graphene, which enhance the thermal stability, sintering resistance, and electronic structure of iron carbides, thereby reducing CO₂ emissions and promoting selective formation of desired hydrocarbon products. This innovative approach offers new opportunities for developing catalysts with high activity, low CO2 selectivity, and enhanced stability, which are key factors for enhancing both the efficiency and sustainability for FTS. Such advancements are crucial for advancing more efficient and sustainable FTS technologies, supporting the global push for net-zero emissions goals, and contributing to carbon reduction efforts worldwide.

The results were published in Chinese Journal of Catalysis (DOI: 10.1016/S1872-2067(25)64738-3)

About the Journal

Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top one journals in Applied Chemistry with a current SCI impact factor of 17.7. The Editors-in-Chief are Profs. Can Li and Tao Zhang.

At Elsevier http://www.journals.elsevier.com/chinese-journal-of-catalysis

Manuscript submission https://mc03.manuscriptcentral.com/cjcatal

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Journal

Chinese Journal of Catalysis

DOI

10.1016/S1872-2067(25)64738-3 

Article Title

Advances in iron-based Fischer-Tropsch synthesis with high carbon efficiency

 

Psychological comorbidity in patients presenting to the emergency department with low-risk chest pain and anxiety

Regenstrief Institute

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INDIANAPOLIS -- Chest pain ranks as the second most common reason for emergency department (ED) visits, making it a key concern for patients and doctors. However, 80 percent of these cases are considered low-risk and not related to heart disease, and for these patients, anxiety and panic disorders are frequent diagnoses.

A new study led by the Indiana University School of Medicine and Regenstrief Institute researchers shows that many patients who visit the ED with low-risk chest pain might benefit more from treatment for underlying psychological conditions than from extensive cardiac testing.

Anxiety is not only common among low-risk chest pain patients, but is often accompanied by other treatable comorbidities, including depression, somatization – the experience of psychological distress through physical symptoms – and post-traumatic stress disorder. By identifying and addressing these conditions, more targeted follow-up strategies can be developed to reduce repeat ED visits and unnecessary evaluations, improving patient outcomes and allowing health systems to focus resources where they matter most.

“Anxiety is a common fellow traveler with low-risk chest pain,” said corresponding author, IU School of Medicine and Regenstrief Research Scientist Kurt Kroenke, M.D. “It is a frequent issue in the emergency department. While many patients worry about their heart, in many cases the chest pain is not cardiac, which raises the important question of whether there is something else that can be treated.”

The research, part of the Patient-Centered Treatment of Anxiety after Low-Risk Chest Pain in the Emergency Room (PACER) trial, showed that more than 42 percent of patients had severe anxiety, defined by a score of 15 or higher on the Generalized Anxiety Disorder (GAD-7) scale, a standardized tool developed by Dr. Kroenke to assess the severity of anxiety symptoms. In addition, three-quarters of ED patients screened positive for panic disorder.

Evidence-based treatments for anxiety and comorbidities

Two effective approaches to reduce anxiety in patients with low-risk chest pain: Cognitive Behavioral Therapy (CBT) and prescription medications were identified in the study. These treatments can be used on their own or combined to create a more comprehensive care plan, helping to better manage symptoms and prevent unnecessary return visits to the ED.

Psychotropic medications such as antidepressants and anti-anxiety medicines remain important tools for managing anxiety disorders. When used appropriately, these medications can lessen both the intensity and frequency of symptoms and are often most effective when paired with psychological therapy.

“There are classes of medicines that are effective for anxiety, particularly when it’s chronic,” said Dr. Kroenke. “It’s no different than taking a medicine for high blood pressure – if someone has high blood pressure, we have medicines that lower it. Similarly, if someone has high anxiety, we have medicines that can effectively reduce it.”

The other effective approach is CBT, which helps individuals recognize and reframe thought patterns, manage panic symptoms and reduce fear associated with chest discomfort. Research shows that even brief courses of this behavioral therapy can significantly improve anxiety and quality of life. The PACER trial compared standard therapist-administered CBT to peer-supported internet-based CBT in patients with LRCP and anxiety.

“Emergency physicians often reassure patients that their chest pain isn’t caused by the heart, but reassurance alone is not enough. Connecting patients with proven therapies like cognitive-behavioral therapy and medications can change the trajectory of their care and improve long-term outcomes,” said IU School of Medicine and Regenstrief Researcher Paul Musey, M.D., M.S.

This research was supported by Patient-Centered Outcomes Research Institute (CER2019C3-17869).

“Psychological Comorbidity in Patients Presenting to the Emergency Department With Low-Risk Chest Pain and Anxiety,” is published in Academic Emergency Medicine.

Authors and their affiliations, as listed in the publication are:

Linh Dang1, Kurt Kroenke2, Jill Connors3, Timothy E Stump4, Patrick O Monahan4, Yelena Chernyak5, Emily Holmes5, Colin Hoffman4, Kevin Prather6, Paul I Musey6

Affiliations

1Indiana University School of Medicine, Indianapolis, Indiana, USA.

2Department of Medicine, Indiana University School of Medicine and Regenstrief Institute, Indianapolis, Indiana, USA.

3Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA.

4Department of Biostatistics and Health Data Sciences, Indiana University School of Medicine, Indianapolis, Indiana, USA.

5Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA.

6Department of Emergency Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA.

Kurt Kroenke, M.D.
In addition to his role as a research scientist with the William M. Tierney Center for Health Services Research at Regenstrief Institute, Kurt Kroenke M.D., is an IU Indianapolis Chancellor’s Professor and a professor of medicine at Indiana University School of Medicine. 

Paul I. Musey Jr., M.D., M.S.
In addition to his role as a research scientist with the William M. Tierney Center for Health Services Research at Regenstrief Institute, Paul Musey Jr., M.D., M.S., is the Eskenazi Health Foundation Chair and Scholar of Emergency Medicine and associate professor and vice chair of research for the Indiana University School of Medicine Department of Emergency Medicine. He also is medical director, IU Health Enterprise Clinical Research Operations (ECRO).

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Journal

Academic Emergency Medicine

DOI

10.1111/acem.70113 

Article Title

Psychological Comorbidity in Patients Presenting to the Emergency Department With Low-Risk Chest Pain and Anxiety

Study shows mucus contains molecules that block Salmonella infection

MIT researchers now hope to develop synthetic versions of these molecules, which could be used to treat or prevent foodborne illnesses

Massachusetts Institute of Technology

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MIT researchers have discovered how mucins found in the mucus that lines the digestive tract can disarm the bacterium that causes Salmonella (purple).

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Credit: MIT

CAMBRIDGE, MA -- Mucus is more than just a sticky substance: It contains a wealth of powerful molecules called mucins that help to tame microbes and prevent infection. In a new study, MIT researchers have identified mucins that defend against Salmonella and other bacteria that cause diarrhea.

The researchers now hope to mimic this defense system to create synthetic mucins that could help prevent or treat illness in soldiers or other people at risk of exposure to Salmonella. It could also help prevent “traveler’s diarrhea,” a gastrointestinal infection caused by consuming contaminated food or water.

Mucins are bottlebrush-shaped polymers made of complex sugar molecules known as glycans, which are tethered to a peptide backbone. In this study, the researchers discovered that a mucin called MUC2 turns off genes that Salmonella uses to enter and infect host cells.

“By using and reformatting this motif from the natural innate immune system, we hope to develop strategies to preventing diarrhea before it even starts. This approach could provide a low-cost solution to a major global health challenge that costs billions annually in lost productivity, health care expenses, and human suffering,” says Katharina Ribbeck, the Andrew and Erna Viterbi Professor of Biological Engineering at MIT and the senior author of the study.

MIT Research Scientist Kelsey Wheeler PhD ’21 and Michaela Gold PhD ’22 are the lead authors of the paper, which appeared Tuesday in the journal Cell Reports.

Blocking infection

Mucus lines much of the body, providing a physical barrier to infection, but that’s not all it does. Over the past decade, Ribbeck has identified mucins that can help to disarm Vibrio cholerae, as well as Pseudomonas aeruginosa, which can infect the lungs and other organs, and the yeast Candida albicans.

In the new study, the researchers wanted to explore how mucins from the digestive tract might interact with Salmonella enterica, a foodborne pathogen that can cause illness after consuming raw or undercooked food, or contaminated water.

To infect host cells, Salmonella must produce proteins that are part of the type 3 secretion system (T3SS), which helps bacteria form needle-like complexes that transfer bacterial proteins directly into host cells. These proteins are all encoded on a segment of DNA called Salmonella pathogenicity island 1 (SPI-1).

The researchers found that when they exposed Salmonella to a mucin called MUC2, which is found in the intestines, the bacteria stopped producing the proteins encoded by SPI-1, and they were no longer able to infect cells.

Further studies revealed that MUC2 achieves this by turning off a regulatory bacterial protein known as HilD. When this protein is blocked by mucins, it can no longer activate the T3SS genes.

Using computational simulations, the researchers showed that certain monosaccharides found in glycans, including GlcNAc and GalNAc, can attach to a specific binding site of the HilD protein. However, their studies showed that these monosaccharides can’t turn off HilD on their own — the shutoff only occurs when the glycans are tethered to the peptide backbone of the mucin.

The researchers also discovered that a similar mucin called MUC5AC, which is found in the stomach, can block HilD. And, both MUC2 and MUC5AC can turn off virulence genes in other foodborne pathogens that also use HilD as a gene regulator.

Mucins as medicine

Ribbeck and her students now plan to explore ways to use synthetic versions of these mucins to help boost the body’s natural defenses and protect the GI tract from Salmonella and other infections.

Studies from other labs have shown that in mice, Salmonella tends to infect portions of the GI tract that have a thin mucus barrier, or no barrier at all.

“Part of Salmonella’s evasion strategy for this host defense is to find locations where mucus is absent and then infect there. So, one could imagine a strategy where we try to bolster mucus barriers to protect those areas with limited mucin,” Wheeler says.

One way to deploy synthetic mucins could be to add them to oral rehydration salts — mixtures of electrolytes that are dissolved in water and used to treat dehydration caused by diarrhea and other gastrointestinal illnesses.

Another potential application for synthetic mucins would be to incorporate them into a chewable tablet that could be consumed before traveling to areas where Salmonella and other diarrheal illnesses are common. This kind of “pre-exposure prophylaxis” could help prevent a great deal of suffering and lost productivity due to illness, the researchers say.

“Mucin mimics would particularly shine as preventatives, because that’s how the body evolved mucus — as part of this innate immune system to prevent infection,” Wheeler says.

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The research was funded by the U.S. Army Research Office, the U.S. Army Institute for Collaborative Biotechnologies, the U.S. National Science Foundation, the U.S. National Institute of Health and Environmental Sciences, the U.S. National Institutes of Health, and the German Research Foundation.

 

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Journal

Cell

DOI

10.1016/j.celrep.2025.116304 

Article Title

Mucus-derived glycans are inhibitory signals for Salmonella Typhimurium SPI-1-mediated invasion

Article Publication Date

23-Sep-2025

 

Deadly pathogens found in commercial raw cat foods

Cornell University

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ITHACA, N.Y. – An analysis of commercial raw cat foods detected disease-causing microbes, including some that are resistant to antibiotics, creating risks for both pets and their owners, according to a new Cornell University study.

The paper, published in Communications Biology, found Salmonella, Cronobacter and E. coli in such foods as raw or partially cooked meat sold frozen, refrigerated and freeze-dried in stores and online. These pathogens can transfer from pets to humans and are of special concern for young children, and people who are old, pregnant and immuno-compromised.

“Most of these products have no warning labels on them showing that the meat ingredients are not fully cooked, indicating that they could harbor live bacteria and potentially viruses and parasites that would make a family very sick.,” said Laura Goodman, assistant professor in the Department of Public and Ecosystem Health. “Particularly for the freeze-dried products sold on shelves, consumers likely have no idea they are taking on that risk.”

The Food and Drug Administration regulates and tests a limited number of bacteria in raw cat foods, due to compliance policies, which mainly focus on human pathogens. The paper provides evidence of a wider range of pathogens found in raw cat foods, that might be used to inform the agency’s future policies. 

In the study, the researchers purchased a mix of raw and conventionally cooked cat foods. They then compared the communities of microorganisms, known as microbiomes, in each sample, applying the same methods practiced by the FDA when they cultured bacterial samples.

The team detected five strains of salmonella in raw food samples, which they uploaded to the federal database that is used to match with human cases of salmonellosis. “There were indeed some human cases that were genetically very similar to our isolates,” revealing that people potentially were sickened from the same products studied, Goodman said.

They also applied nonstandard culturing methods and isolated antibiotic-resistant pseudomonas, a bacteria that can cause serious, life-threatening lung, blood and urinary tract infections.

Klebsiella, a bacteria that can cause fever, chills and fatigue, and potentially pneumonia and urinary tract infections, was also found in raw samples, though it is not necessarily considered a foodborne pathogen, Goodman said. Clostridium perfringens, the bacteria that leads to gastroenteritis in undercooked turkey, and causes food poisoning around Thanksgiving, was highly associated in the microbiomes of the freeze-dried cat treats and coated kibble.

For additional information, read this Cornell Chronicle story.

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Journal

Communications Biology

DOI

10.1038/s42003-025-08756-8