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Microplastics are tangible particles of less than 0.2 inches in diameter that are ubiquitously distributed in the biosphere and accumulate in water bodies. During the east-coast hot summers (23–29 °C) of 2021 and 2022, June through September, we captured copious amounts of the jellyfish Chrysaora chesapeakei, a predominant species found in the Patuxent River of the Chesapeake Bay in Maryland on the United States East Coast. We determined that their gelatinous bodies trapped many microplastics through fluorescent microscopy studies using Rhodamine B staining and Raman Spectroscopy. The chemical nature of the microplastics was detected using gas chromatography–mass spectroscopy headspace (SPME-GC-MS) and solvent extraction (GC-MS) methods through a professional commercial materials evaluation laboratory. Numerous plastic-affiliated volatile organic compounds (VOCs) from diverse chemical origins and their functional groups (alkanes, alkenes, acids, aldehydes, ketones, ethers, esters, and alcohols) along with other non-microplastic volatile organic compounds were observed. Our findings corroborate data in the available scientific literature, distinguishing our finding's suitability. [ABSTRACT FROM AUTHOR]

Untangling organisms' multi‐scale spatial distributions is challenging due to their interactions with environments at multiple spatial and temporal scales. We deployed an Adaptive Resolution Imaging Sonar (ARIS) in a Chesapeake Bay sub‐estuary to investigate multi‐scale spatial distributions of the bay nettle (Chrysaora chesapeakei) in May–September of 2016 and 2017. Nettles were found to be dispersed in aggregations of multiple individuals. The average density of bay nettles in 2017 was higher than in 2016. Small aggregations (<5 m) were persistent in both years but only contributed <10% of total observed nettles. Large patches (>30 m) contributed ~40% of the total observed nettles. Large patches were more common in creek habitat where nettle density was higher. Nettle density was found to hit a peak value once in 2016, while there were two density peaks in 2017. Different aggregation patterns were observed during the second peak period in 2017 in which the number of large patches increased dramatically. Within the surveyed waterscape, the spatial patterns were consistent over time with higher abundance in the source creek than in the river channel, which underscores that C. chesapeakei requires hard substrate in shallow creeks for its benthic polyp stage. Using the ratio between nettles in the creek and near creek mouth as a proxy for dispersal rate, more nettles were transported out of the creek in 2017 than in 2016. The increase in patch size and high dispersion rate in peak periods in 2017 suggests that individuals were moving out of the creek habitat as density increased. Results highlight the complex spatial structure of bay nettles, which has major impacts on density estimates and subsequently affects our understanding of jellyfish population dynamics and long‐term trends. [ABSTRACT FROM AUTHOR]

Abstract: During a 4-week period in late spring 1998 an extensive Prorocentrum minimum (Pavillard) Schiller bloom developed in several tributaries of the Chesapeake Bay. Experiments were carried out in one of these tributaries using 13C and 15N isotopic techniques to characterize C and N uptake as a function of irradiance during the course of this bloom. Uptake rates of N substrates (NO3-, NH4+, urea, and an amino acid mixture) and C substrates (bicarbonate and urea) were measured. For each N substrate, short-term uptake rates (0.5h) were not substantially different over the irradiance range measured, suggesting that N uptake of this dinoflagellate was not strongly light-dependent over this time scale. Dark uptake rates of all N substrates ranged between 35 and 113% of light uptake rates. Over the duration of the P. minimum bloom, however, total ambient N uptake rates increased with increasing natural irradiance. Uptake of bicarbonate showed typical light-dependent photosynthetic characteristics and the measured photosynthetic parameters suggested that at least on the short time scale (0.5h), P. minimum cells were adapted to high light. Rates of C uptake from the substrate urea were minimal, <1% of total C uptake from photosynthesis, but doubled over the course of the bloom, and like N uptake, were not strongly light-dependent on the short time scale (0.5h). Significant N dark uptake by P. minimum was likely to have been important by providing N sources over the daily scale to sustain the bloom. [Copyright &y& Elsevier]

• Traditional surveys do not efficiently sample forage fish in shallow estuaries. • Sonar imaging produces high-resolution, fine-scale forage fish distribution data. • Forage fish mostly aggregate in shallow water creeks. • We recommend sonar imaging be used to supplement traditional sampling approaches. Forage fish are economically and ecologically important to many coastal marine ecosystems, but most forage fish species are not targeted in species-specific abundance surveys. In the Chesapeake Bay, Atlantic menhaden (Brevoortia tyrannus), an important forage species for many upper-trophic level consumers, are sampled with beach seines and midwater trawls. There is evidence that these traditional fish sampling gears are insufficient for observing menhaden abundance and distribution, which may lead to biased and inaccurate indices of abundance. We suggest this is due to omitting or under-sampling shallow estuarine creeks and nearshore areas. We tested this hypothesis in the Patuxent River, Maryland and its surrounding shallow-water creeks, which are representative of many estuarine tributaries with varied bathymetry. Sonar imaging surveys were conducted using Adaptive Resolution Imaging Sonars (ARIS 1800 and 3000) and a generalized additive model was fit to the resulting data to model forage fish density. Results indicated that menhaden and other forage fish were present at significantly higher densities in shallow-water creeks than in deeper-water areas. Further, many forage fish were observed in creek habitats frequently omitted by both seines and trawls, suggesting that these survey designs may result in biased forage fish indices of abundance. Therefore, we recommend current forage fish surveys in the Chesapeake Bay, especially those with the intent of developing juvenile menhaden indices of abundance, be supplemented with hydroacoustic surveys in shallow waters to improve accuracy and reduce bias. [ABSTRACT FROM AUTHOR]