Ctenophores (Mnemiopsis leidyi) release large amounts of nutrients and organic matter that stimulate microbial growth and alter planktonic community composition. We investigated the distribution and abundance of M. leidyi and its association with pathogenic Vibrio and harmful algal bloom (HAB) species at seven sites in the Maryland Coastal Bays (MCBs) between April 2021 and June 2022. Water and M. leidyi samples were collected concurrently with temperature, salinity, dissolved oxygen, nutrient, and turbidity data. M. leidyi was present in both years at all sites but was most abundant in areas with high turbidity (Isle of Wight and Newport Bays). Both V. parahaemolyticus and V. vulnificus were present in M. leidyi tissue and water samples and had a moderate positive association with turbidity. HAB species composition varied significantly between sites, with distinct populations of the dinoflagellate Karlodinium veneficum (Chincoteague Bay) and picoplankton taxa (Newport Bay) noted. A generalized linear model (GLM) revealed that temperature was best at predicting total (vvhA+) V. vulnificus in M. leidyi tissues and total dissolved nitrogen (TDN) was best at predicting total (trh+) V. parahaemolyticus in water. There was no strong association between M. leidyi abundance and HABs. However, we observed weakly positive associations between V. vulnificus in M. leidyi tissues and total dinoflagellate biomass, between M. leidyi abundance and dinoflagellate biomass, and between V. parahaemolyticus in M. leidyi tissues and picocyanobacteria biomass. This study provides information on associations between M. leidyi, Vibrio spp., and HAB species that could aid the development of a Vibrio predictive model for the MCBs.IMPORTANCEVibrio and algal bloom species naturally occur in marine ecosystems; however, some species of Vibrio and algae can be harmful to humans, causing gastroenteritis. Vibrio-associated illnesses have been expanding globally in marine environments, and many studies have linked this expansion to increases in water temperatures, nutrients, and plankton blooms. We observed seasonal interactions between Vibrio spp., Mnemiopsis leidyi, and HABS and found that temperature was the best predictor of total (vvhA+) V. vulnificus, while TDN was the best predictor of total (trh+) V. parahaemolyticus. These findings provide biotic and abiotic factors that managers, researchers, and stakeholders can use in the development of HAB and Vibrio spp. mitigation strategies and predictive models for the MCBs.

Shewanella is a genus of Gram-negative marine bacteria with some species associated with human and shellfish illnesses. This study evaluated the abundance of Shewanella species in oysters and seawater from the Chesapeake and Maryland Coastal Bays at four sites between 2019 and 2021. Physicochemical parameters such as temperature, salinity, dissolved oxygen, turbidity, pH, chlorophyll-a, rainfall within the last 48 h, total dissolved solids, and atmospheric pressure were also recorded to evaluate if there was a correlation between environmental parameters and the level of Shewanella. The highest total Shewanella counts were 1.8 × 107 CFU/g in oysters and 4.0 × 102 CFU/mL in seawater. 16S rRNA sequencing was performed on 1,344 representative isolates of which 890 (713 oyster, 177 seawater) were confirmed as Shewanella within 16 species. The top four species isolated from oysters and seawater were S. khirikhana a known shrimp pathogen (49%), S. marisflavi (19%), S. loihica (11%), and S. algae (8%). Testing for alpha and beta hemolysis were performed on all confirmed Shewanella isolates. Beta hemolysis was observed in 405 (46%) of the isolates of which 313 were in oysters and 92 in seawater. In oysters, beta-hemolysis was most prevalent in S. khirikhana (233 of 344 isolates, 68%), while in seawater 64 of 92 isolates (70%) were beta-hemolytic strains. Beta-hemolysis suggests that these could be potentially pathogenic strains. Correlations were performed between physicochemical attributes of the seawater and Shewanella counts. Only seawater temperature and dissolved oxygen correlated with Shewanella counts (r = 0.45 and − 0.41), respectively. No correlations were observed between the physicochemical parameters and Shewanella abundances in oysters. Results suggest that virulent strains of Shewanella may be present in oysters and seawater from the Chesapeake and Maryland Coastal Bays, perhaps as a consequence of rising seawater temperatures.

IntroductionFluctuations in water quality characteristics influence the productivity of blue crabs (Callinectes sapidus), and the risk of human exposure to pathogenic Vibrio species. Thus, this study assessed the prevalence of total and pathogenic/clinical markers of Vibrio parahaemolyticus and Vibrio vulnificus in blue crabs and seawater from the Maryland Coastal Bays (MCBs) and the correlation between Vibrio levels and physicochemical parameters.MethodsThree to five crabs and 1 L of seawater were collected monthly for 3 years (May 2018 to December 2020) from six sites within the MCBs. Hemolymph and crab tissue were extracted and pooled for each site. Extracted hemolymph, crab tissue, and seawater were analyzed for V. parahaemolyticus and V. vulnificus using the Most Probable Number (MPN) and real-time PCR methods. A one-way Analysis of Variance (ANOVA), correlations, and linear models were used to analyze the data. Akaike Information Criterion (AICc) was evaluated to determine the model that provides the best fit to the data relating to Vibrio concentrations and environmental factors.ResultsResults suggested that environmental factors could influence the growth of Vibrio spp. Both V. parahaemolyticus and V. vulnificus were more prevalent during the warmer months than colder months. Vibrio was more prevalent in crab samples compared to seawater. Vibrio vulnificus concentrations in seawater and hemolymph were positively correlated with temperature (p = 0.0143 seawater) and pH (p = 0.006 hemolymph). A negative correlation was observed between the concentration of V. vulnificus in whole crab (tissue) and dissolved oxygen level (p = 0.0256). The concentration of V. parahaemolyticus in seawater was positively correlated with temperature (p = 0.009) and negatively correlated with dissolved oxygen (p = 0.012).DiscussionThese results provide current information on the spatial and temporal distributions of Vibrio spp. in the MCBs that are useful for implementing more efficient processing and handling procedures of seafood products.

Vibrio vulnificus is a naturally occurring pathogenic marine bacterium that is found in coastal waters. Infections from V. vulnificus infections can occur from wound exposure to contaminated water as well as consuming raw or undercooked seafood. Despite low case numbers of 50-60 per year in the United States, V. vulnificus is commonly found in brackish water like in Chesapeake Bay. Predictive models have been developed to predict occurrence of V. vulnificus based on temperature and salinity, two known drivers of V. vulnificus abundance. Though these models can predict the abundance of bacteria, they do not predict the likelihood of infection due to the lack of understanding surrounding virulence. Also, the individual health status of the person exposed is an important predictor of illness but is not typically available for research purposes. This work utilizes V. vulnificus case numbers from the Virginia Department of Health coupled with model predictions from an operational habitat suitability model that would predict the number of infections. The results indicate a relationship between per capita wound infection cases and the probability of the pathogen being present in tidal waters of the Chesapeake Bay (VA).

The white perch ( Morone americana ) is an abundant estuarine teleost in eastern North America, with its commercial and trophic importance creating a need for fecundity and recruitment data. In this study, we reevaluated the fecundity of subpopulations of white perch in Chesapeake Bay. Stereological sampling methods were used to determine if environmental changes in the Chesapeake Bay watershed over the last 60 years have altered average fecundity of this species. These methods were compared with automated gravimetric methods to determine the efficacy of using stereological fecundity sampling for white perch. The results of using both methods were statistically the same, as indicated by a Lin's concordance correlation coefficient of 0.98 and a favorable distribution on Bland-Altman plots. After the stereological methods were validated, archival histological samples from the Choptank River subestuary were evaluated for fecundity over a 4- year period of sampling. Results indicate that fecundity of white perch has been reasonably unchanged in the river system, with an average estimated fecundity of 69,379 oocytes per fish. These findings indicate the resiliency of the reproduction of white perch in mesohaline Chesapeake Bay, despite widespread environmental change.

Summary The wheat flag leaf is the main contributor of photosynthetic assimilates to developing grains. Understanding how canopy architecture strategies affect source strength and yield will aid improved crop design. We used an eight‐founder population to investigate the genetic architecture of flag leaf area, length, width and angle in European wheat. For the strongest genetic locus identified, we subsequently created a near‐isogenic line (NIL) pair for more detailed investigation across seven test environments. Genetic control of traits investigated was highly polygenic, with colocalisation of replicated quantitative trait loci (QTL) for one or more traits identifying 24 loci. For QTL QFll.niab‐5A.1 (FLL5A), development of a NIL pair found the FLL5A+ allele commonly conferred a c. 7% increase in flag and second leaf length and a more erect leaf angle, resulting in higher flag and/or second leaf area. Increased FLL5A‐mediated flag leaf length was associated with: (1) longer pavement cells and (2) larger stomata at lower density, with a trend for decreased maximum stomatal conductance (Gsmax) per unit leaf area. For FLL5A, cell size rather than number predominantly determined leaf length. The observed trade‐offs between leaf size and stomatal morphology highlight the need for future studies to consider these traits at the whole‐leaf level.

In the context of a continuously increasing human population that needs to be fed, with environmental pro-tection in mind, nitrogen use efficiency (NUE) improvement is becoming very important. To understand the natural variation of traits linked to nitrogen uptake efficiency (UPE), one component of NUE, the multiparent advanced generation intercross (MAGIC) winter wheat population WM-800 was phenotyped under two con-trasting nitrogen (N) levels in a high-throughput phenotyping facility for six weeks. Three biomass-related, three root-related, and two reflectance-related traits were measured weekly under each treatment. Subsequently, the population was genetically analysed using a total of 13,060 polymorphic haplotypes and singular SNPs for a genome-wide association study (GWAS). In total, we detected 543 quantitative trait loci (QTL) across all time points and traits, which were pooled into 42 stable QTL (sQTL; present in at least three of the six weeks). Besides Rht-B1 and Rht-D1, candidate genes playing a role in gibberellic acid-regulated growth and nitrate transporter genes from the NPF gene family, like NRT 1.1, were linked to sQTL. Two novel sQTL on chromosomes 5 A and 6D showed pleiotropic effects on several traits. The high number of N-specific sQTL indicates that selection for UPE is useful specifically under N-limited conditions.

OBJECTIVE:Modeling of fecundity with allometric, nutritional, and environmental covariates has increased sensitivity of reproductive metrics in many fish species. In estuaries with heavy anthropogenic influence, resident species often experience sublethal health impacts because of increased stress, which can include increases in gonadal pathology, intersex, or potential reproductive failure. This study models the fecundity of the estuarine species White Perch Morone americana in response to health parameters identified as signals of habitat stress, including gross pathology presentation, nutritional condition, and disease presence.METHODS:Subpopulation fecundity in the Choptank River (Maryland) of the Chesapeake Bay was estimated using stereological fecundity sampling methods and modeled using information-theoretic approaches of model selection. Nutritional and health parameters identified through health assessment techniques, specific somatic indices, and disease presence were selected as covariates.RESULT:Nutrition demonstrated limited influence on model fit as compared to models with only conventional allometric variables such as weight and length. Of the health variables, gross pathology and somatic indices showed minimal influence on selection, but mycobacterial infection, a chronic condition in the Chesapeake Bay among temperate basses, showed measurable influence. Models with mycobacteriosis included were 40 times more likely the best fit when compared to models with only allometric parameters.CONCLUSION:Whether this has a region-wide influence on all subpopulations will require further research and sampling of the magnitude of mycobacteriosis infection.

Vibrio parahaemolyticus is the leading cause of seafood-related gastroenteritis in the United States, with an estimated 45,000 cases per year. Most individuals who suffer from vibriosis consume raw or undercooked seafood, including oysters.

Two homoeologous QTLs for number of spikelets per spike (SPS) were mapped on chromosomes 7AL and 7BL using two wheat MAGIC populations. Sets of lines contrasting for the QTL on 7AL were developed which allowed for the validation and fine mapping of the 7AL QTL and for the identification of a previously described candidate gene, WHEAT ORTHOLOG OF APO1 ( WAPO1 ). Using transgenic overexpression in both a low and a high SPS line, we provide a functional validation for the role of this gene in determining SPS also in hexaploid wheat. We show that the expression levels of this gene positively correlate with SPS in multiple MAGIC founder lines under field conditions as well as in transgenic lines grown in the greenhouse. This work highlights the potential use of WAPO1 in hexaploid wheat for further yield increases. The impact of WAPO1 and SPS on yield depends on other genetic and environmental factors, hence, will require a finely balanced expression level to avoid the development of detrimental pleiotropic phenotypes.

Vibrio spp. and phytoplankton are naturally abundant in marine environments. Recent studies have suggested that the co-occurrence of phytoplankton and the pathogenic bacterium Vibrio parahaemolyticus is due to shared ecological factors, such as nutrient requirements. We compared these communities at two locations in the Delaware Inland Bays, representing a site with high anthropogenic inputs (Torquay Canal) and a less developed area (Sloan Cove). In 2017 to 2018, using light microscopy, we were able to identify the presence of many bloom-forming algal species, such as Karlodinium veneficum, Dinophysis acuminata, Heterosigma akashiwo, and Chattonella subsalsa. Dinoflagellate biomass was higher at Torquay Canal than that at Sloan Cove. D. acuminata and Chloromorum toxicum were found only at Torquay Canal and were not observed in Sloan Cove. Most probable number real-time PCR revealed V. parahaemolyticus and Vibrio vulnificus in environmental samples. The abundance of vibrios and their virulence genes varied between sites, with a significant association between total dissolved nitrogen (TDN), PO4-, total dissolved phosphorus (TDP), and pathogenic markers. A generalized linear model revealed that principal component 1 of environmental factors (temperature, dissolved oxygen, salinity, TDN, PO4-, TDP, NO3:NO2, NO2-, and NH4+) was the best at detecting total (tlh+) V. parahaemolyticus, suggesting that they are the prime drivers for the growth and distribution of pathogenic Vibrio spp. IMPORTANCE Vibrio-associated illnesses have been expanding globally over the past several decades (A. Newton, M. Kendall, D. J. Vugia, O. L. Henao, and B. E. Mahon, Clin Infect Dis 54:S391-S395, 2012, https://doi.org/10.1093/cid/cis243). Many studies have linked this expansion with an increase in global temperature (J. Martinez-Urtaza, B. C. John, J. Trinanes, and A. DePaola, Food Res Int 43:10, 2010, https://doi.org/10.1016/j.foodres.2010.04.001; L. Vezzulli, R. R. Colwell, and C. Pruzzo, Microb Ecol 65:817-825, 2013, https://doi.org/10.1007/s00248-012-0163-2; R. N. Paranjpye, W. B. Nilsson, M. Liermann, and E. D. Hilborn, FEMS Microbiol Ecol 91:fiv121, 2015, https://doi.org/10.1093/femsec/fiv121). Temperature and salinity are the two major factors affecting the distribution of Vibrio spp. (D. Ceccarelli and R. R. Colwell, Front Microbiol 5:256, 2014, https://doi.org/10.3389/fmicb.2014.00256). However, Vibrio sp. abundance can also be affected by nutrient load and marine plankton blooms (V. J. McKenzie and A. R. Townsend, EcoHealth 4:384-396, 2007; L. Vezzulli, C. Pruzzo, A. Huq, and R. R. Colwell, Environ Microbiol Rep 2:27-33, 2010, https://doi.org/10.1111/j.1758-2229.2009.00128.x; S. Liu, Z. Jiang, Y. Deng, Y. Wu, J. Zhang, et al. Microbiologyopen 7:e00600, 2018, https://doi.org/10.1002/mbo3.600). The expansion of Vibrio spp. in marine environments calls for a deeper understanding of the biotic and abiotic factors that play a role in their abundance. We observed that pathogenic Vibrio spp. were most abundant in areas that favor the proliferation of harmful algal bloom (HAB) species. These results can inform managers, researchers, and oyster growers on factors that can influence the growth and distribution of pathogenic Vibrio spp. in the Delaware Inland Bays.

Researchers have developed multiple methods to characterize clinical and environmental strains of Vibrio vulnificus. The aim of our study was to use four assays to detect virulence factors in strains from infected patients and those from surface waters/sediments/oysters of South Carolina and the Gulf of Mexico. Vibrio vulnificus strains from clinical (n = 81) and environmental (n = 171) sources were tested using three real-time PCR methods designed to detect polymorphisms in the 16S rRNA, vcg and pilF genes and a phenotypic method, the ability to ferment D-mannitol. Although none of the tests correctly categorized all isolates, the differentiation between clinical and environmental isolates was similar for the pilF, vcgC/E and 16S rRNA assays, with sensitivities of 74.1-79.2% and specificities of 77.4-82.7%. The pilF and vcgC/E assays are comparable in efficacy to the widely used 16S rRNA method, while the D-mannitol fermentation test is less discriminatory (sensitivity = 77.8%, specificity = 61.4%). Overall percent agreement for the D-mannitol fermentation method was also lower (66.7%) than overall percent agreement for the 3 molecular assays (78.0%?80.2%). This study demonstrated, using a large, diverse group of Vibrio vulnificus isolates, that three assays could be used to distinguish most clinical vs environmental isolates; however, additional assays are needed to increase accuracy.

The bacterium Vibrio parahaemolyticus (Vp) causes gastrointestinal illness in people, generally through the consumption of undercooked or raw seafood. It is a major concern in the oyster industry, especially as the raw oyster market gains in popularity. As a result, a network of adaptive regulations is triggered during times when Vp risk is high (i.e., during warmer temperatures) and reporting requirements to track confirmed infections. A survey of three main stakeholder groups-managers, growers, and restaurants/retail locations-estimated the costs of these regulations for the Washington State oyster industry to quantify their economic burden. Study participants requested that these costs be categorized by actual dollars spent and labor hours needed, and then again by whether those expenses were part of Vp prevention efforts or as the result of a traceable illness. The survey revealed that prevention efforts cost an average $0.45 per dozen oysters landed and a traceable case costs an average of $61,880 for 2019. These costs are largely borne by growers in the form of fixed costs and therefore, there is also an economy of scale at play. The discussion then focuses on how these costs may apply to future management plans and farm budgets, as well as other geographies.

Over the last decade, an increase of gastrointestinal illness due to Vibrio parahaemolyticus in the consumption of raw shellfish has been reported in multiple regions around the United States. Studies mainly attribute this increase to rising sea surface temperatures and prolonged warm seasons in the mid-latitudes. Historically, temperature has been the main environmental determinant used to predict V. parahaemolyticus concentrations in shellfish and surface water. However, studies using in situ sampling campaigns have shown that additional water quality parameters can be useful in predicting the bacterium. While the time and cost of obtaining in situ samples throughout the Chesapeake Bay at regular time intervals can exceed available resources, satellite remote sensing has the potential to provide predictions at higher temporal and spatial resolutions. This study uses satellite ocean color remote sensing and sea surface temperature (SST) from the Moderate Resolution Imaging Spectroradiometer (MODIS) to investigate the utility of remotely sensed information for Vibrio parahaemolyticus predictions in the Chesapeake Bay and whether additional remotely sensed information can improve predictions over conventional SST-based models. We find that the addition of remotely sensed salinity, total suspended solids, and chlorophyll-a generally improves presence and abundance predictions compared to SST-only models. Models using remote sensing reflectances and SST also show potential for V. parahaemolyticus predictions, which could bypass the intermediary step of deriving water quality products from reflectances. Remotely sensed ocean color products and SST from one week prior to in situ V. parahaemolyticus measurements are evaluated and shown to be useful in bacterium predictions, which could provide lead-time for management decisions. The forecast models using ocean color products in addition to SST showed improvement over SST-only forecast models. The results of this study suggest that remote sensing can be a valuable tool to aid in higher resolution V. parahaemolyticus predictions and forecasts in the Chesapeake Bay, particularly when multiple environmental predictors are employed. However, the complexities of using remotely sensed data for ecological modeling applications and evaluating model performance also highlight the need for more research in this area.

While V. parahaemolyticus and V. vulnificus cause shellfish-associated morbidity and mortality among shellfish consumers, current regulatory assays for vibrios are complex, time-consuming, labor-intensive, and relatively expensive. In this study, the rapid, simple, and inexpensive COPP assay was identified as a possible alternative to MPN-PCR for shellfish monitoring. This paper shows differences in total Vibrionaceae and pathogenic vibrios found in seawater and oysters from the commercially important Delaware and Chesapeake Bays. Vibrio parahaemolyticus isolates from the Delaware Bay were more likely to contain commonly recognized pathogenicity genes than those from the Chesapeake Bay.

Vibrio parahaemolyticus (V. parahaemolyticus) is a naturallyoccurring bacterium found in estuaries, such as the Chesapeake Bay (USA), that can cause vibriosis, a food - and waterborne illness, in humans. Tracking the spatial and temporal distribution of V. parahaemolyticus in the Chesapeake Bay, which varies in part due to water temperature, salinity, and other environmental variables, can help identify areas and time periods of high risk. These observations can support interventions used to reduce the burden of vibriosis. Spatial and spatiotemporal clusters of high V. parahaemolyticus abundance were identified among surface water samples in the Chesapeake Bay between 2007 and 2010. While Euclidean distances between geographic points in spatial analyses are often used for cluster detection, non-Euclidean distances should be considered for cluster detection due to the complex nature of the Chesapeake Bay shoreline. Comparison of both methods consistently showed the non-Euclidean cluster detection providing unique and more reasonable clusters than the Euclidean approach. Residuals from univariate and multivariate models were used to identify how clusters changed after controlling for environmental variables. Most clusters tended to decrease in space, time, or significance after adjustment, suggesting these covariates contributed to the original formation of the clusters and as such are useful observation tools for vibriosis risk managers. Clusters that remained after adjustment suggest areas for further study and intervention. These findings reinforce the importance of using non-Euclidean distances when tracking the spatiotemporal variation of V. parahaemolyticus as well as the benefits of cluster detection methods for V. parahaemolyticus risk management in estuaries.

Vibrio parahaemolyticusis one of the leading causes of seafood-borne illness in the United States and across the globe. Exposure often occurs from the consumption of raw shellfish. Despite public health concerns, there have been only sporadic efforts to develop environmental prediction and forecast models for the bacterium preharvest. This analysis used commonly sampled water quality measurements of temperature, salinity, dissolved oxygen, and clarity to develop models forV. parahaemolyticusin surface water. Predictors also included measurements taken months before water was tested for the bacterium. Results revealed that the use of multiple water quality measurements is necessary for satisfactory prediction performance, challenging current efforts to manage the risk of infection based upon water temperature alone. The results also highlight the potential advantage of including historical water quality measurements. This analysis shows promise and lays the groundwork for future operational prediction and forecast models.

Vibrio parahaemolyticus naturally occurs in estuaries and is a leading cause of seafood-borne illness. It is therefore necessary to develop ecological prediction tools for shellfish harvesting waters. Such predictions need adequate spatial and temporal resolution as bacterium abundance fluctuates frequently.Previous work identified environmental determinants of V. parahaemolyticus in the tidal waters of the Chesapeake Bay using a large data set (n= 1,385) collected from 148 monitoring stations between 2007-2010. Regression models were developed using water samples analyzed by qPCR along with spatially- and temporally-indexed water quality data. Previously identified relationships with temperature and turbidity were confirmed, while more complex relationships were identified for nitrogen and phosphorus. Non-linear associations with salinity were determined to be a function of both low temperature and turbidity.Recent work attempted to develop V. parahaemolyticus prediction models using time-indexed and 1- and 2-month lagged water quality measures. Tobit regression models were evaluated using cross-validation methods to quantify prediction bias and uncertainty. The results were promising, indicating that water quality data can provide adequate prediction for bacterium presence and abundance, and that lagged measures provide complimentary or superior predictive power when compared to time-indexed measures.Current work is expanding variable selection for prediction models and increase the spatial-temporal extent of such predictions by using geostatistical interpolation techniques. These modeling efforts will culminate in a prediction tool that will provide real-time forecasts of V. parahaemolyticus. These prediction models will better inform shellfish harvesters and regulators on when and where preventative food safety post-harvesting practices are necessary.