Marine Organisms Research Articles

Vibrio cholerae: a fundamental model system for bacterial genetics and pathogenesis research.

Species of the Vibrio genus occupy diverse aquatic environments ranging from brackish water to warm equatorial seas to salty coastal regions. More than 80 species of Vibrio have been identified, many of them as pathogens of marine organisms, including fish, shellfish, and corals, causing disease and wreaking havoc on aquacultures and coral reefs. Moreover, many Vibrio species associate with and thrive on chitinous organisms abundant in the ocean. Among the many diverse Vibrio species, the most well-known and studied is Vibrio cholerae, discovered in the 19th century to cause cholera in humans when ingested. The V. cholerae field blossomed in the late 20th century, with studies broadly examining V. cholerae evolution as a human pathogen, natural competence, biofilm formation, and virulence mechanisms, including toxin biology and virulence gene regulation. This review discusses some of the historic discoveries of V. cholerae biology and ecology as one of the fundamental model systems of bacterial genetics and pathogenesis.

Integrative taxonomy of Tethya: description of four new species based on morphology, phylogeny and microbiome diversity

The genus Tethya, one of the most iconic groups in the phylum Porifera. includes nearly 100 valid species. Tethya shows a nearly cosmopolitan distribution, and thus this clade could help elucidate global mechanisms of speciation in sponges. Contrasting with many other marine organisms, Tethya peaks in diversity in the temperate region, with only ∼30% of diversity occurring in the tropics. This pattern may however be related to a lack of studies in the tropics, masked by dubious taxonomic identifications. To address this question, we studied new collections from the Western Atlantic (Caribbean and Brazil) and the Northeastern Atlantic, as well as museum material from the Indian Ocean. Combining morphological investigation with molecular phylogenetics and the study of the sponge’s microbial communities, we conclude that four constitute new species that we describe here: Tethya martini Riesgo, Giribet, & Santodomingo, sp. nov.; Tethya simoni Santodomingo, Zea, & Riesgo, sp. nov.; Tethya erici Díez-Vives, Santodomingo, Moles, & Riesgo, sp. nov.; Tethya orioni Kenny, Santodomingo & Riesgo, sp. nov. Some species thought to be widespread (e.g., T. aurantium and T. seychellensis), each represent multiple species with unique geographic distributions. A phylogenetic analysis of Tethya (based on COI and 28S rRNA sequence data) recovered five main clades, which were also characterized by distinct prokaryotic communities. This suggests that microbiomes could be used as a guide for taxonomic identification in Tethya. We finally explored the existence of a phylosymbiotic pattern in sponges at different levels of prokaryotic taxonomic resolution (i.e., at phylum, class, and genus-level analysis of prokaryotes). Remarkably, our analysis revealed high levels of coevolution of Tethya and their associated microbial communities, even when microbiomes were analysed at the genus level. Our findings support the use of an integrative approach to better understand the evolutionary history of sponges. http://zoobank.org/urn:lsid:zoobank.org:pub:54F80E5E-99A4-43CE-BA3A-BCD01E715595

Synthesis, Identification, and anti-cancer Evaluation of Some heterocyclic Chitosan-Thiosemicarbazones compounds and their nickle (II) complexes

Chitosan (CS) a chemical substance taken from the shells of sea creatures that has various uses in industry, farming, and medicine, for example in medical dressings. Its derivatives significantly inhibit two types of cancer cells: Madin Darby Canine Kidney MDCK and MCF-7. These derivatives include thiosemicarbazones, heterocyclic moieties, and their metal (II) complexes. In this study, CS from crab shells is mixed with thiosemicarbazide (TSC). Then, imidazole-2-carboxaldehyde, oxazole-2-carboxaldehyde, and thiazole-2-carboxaldehyde reacted to make three different compounds from CS-TSC: [2a], [2b], and [2c]. The chemicals were mixed with nickel chloride to create nickel (II) chitosan 2-acetyl heterocyclic-2-thiosemicarbazone complexes. SEM and X-ray tests were performed on the powder, which showed that the nickel (II) chitosan thiosemicarbazone complexes had square and flat shapes. The synthesized compounds were tested to check their effectiveness in preventing MDCK and MCF-7. The study found that chitosan derivatives significantly inhibited MDCK and MCF-7.

Phytoplankton Spring Bloom Inhibited by Marine Heatwaves in the North‐Western Mediterranean Sea

AbstractMarine heatwaves (MHWs) represent anomalously warm temperature conditions of seawater that may affect marine life and ocean biogeochemistry. Under such conditions, phytoplankton communities may modify their structure and functions, and their resilience is not assured. This study characterizes the impact of MHWs on the phytoplankton spring bloom in the North‐Western Mediterranean Sea. Here, we synergistically combine autonomous observations from BioGeoChemical‐Argo floats, satellite‐based and marine ecosystem model data, and show that MHW events occurring during winter drastically inhibit phytoplankton carbon biomass in spring by up to 70%. Such reduction is related to the enhanced stratification of the water column under MHWs which hinders the renewal of nutrients from deep‐ocean reservoirs, thus preventing surface phytoplankton from blooming. This process negatively impacts particulate organic carbon stocks within the mixed layer, while severe events cause an earlier shift of phytoplankton phenology that provokes changes in zooplankton biomass distribution.

B-FLOWS: Biofouling Focused Learning and Observation for Wide-Area Surveillance in Tidal Stream Turbines

Biofouling, the accumulation of marine organisms on submerged surfaces, presents significant operational challenges across various marine industries. Traditional detection methods are labor intensive and costly, necessitating the development of automated systems for efficient monitoring. The study presented in this paper focuses on detecting biofouling on tidal stream turbine blades using camera-based monitoring. The process begins with dividing the video into a series of images, which are then annotated to identify and select the bounding boxes containing objects to be detected. These annotated images are used to train YOLO version 8 to detect biofouled and clean blades in the images. The proposed approach is evaluated using metrics that demonstrate the superiority of this YOLO version compared to previous ones. To address the issue of misdetection, a data augmentation approach is proposed and tested across different YOLO versions, showing its effectiveness in improving detection quality and robustness.

Chemical synthesis of a trisaccharide fragment of a fucosylated glucuronomannan isolated from brown algae

Fucose is abundant in marine organisms, primarily as fucoidan and fucosylated chondroitin sulfate. Our previous study characterized a sulfated and fucosylated glucuronomannan (SFGM) isolated from marine brown algae, exhibiting notable antiviral activity and potential for drug development. Herein, a trisaccharide fragment of this SFGM in the form of [α-L-Fuc(2, 4-diS)]-(1→3)-α-D-Man-(1→4)-α-D-GlcA-OMP was synthesized for the first time. Stereoselective formation of the α-1,2-cis-fucosidic bond was achieved by leveraging solvent effects. The sulfated trisaccharide as the final product, featuring a 2,4-diS-fucose unit and the p-methoxyphenyl group as a pendant at the anomeric position, was successfully accomplished. The synthetic strategy developed in this study offers a foundation for the pharmaceutical development of these SFGM oligosaccharides.

Influence of Contaminants Mercury and PAHs on Somatic Indexes of the European Hake (Merluccius merluccius, L. 1758).

This research investigates the dynamics of contaminant exposure in European hake (Merluccius merluccius, L. 1758) from the Adriatic Sea (Central Mediterranean Sea) by examining the levels of total mercury (THg) and polycyclic aromatic hydrocarbons (PAHs) in the muscle fish tissues. The study explores the correlations between these pollutants and somatic indexes to identify the early warning signals of pollution and ecological effects. The levels of pollutants are influenced by season and sex. Lipids appear to have a minimal effect on the PAH levels, whereas they exhibit a positive correlation with mercury levels in the muscle. No significant relationships between the pollutants and condition indexes were observed, except for a positive correlation between THg and the gonadosomatic index, indicating a potential impact on the reproductive health of fish. In contrast, PAHs showed no meaningful correlation with condition indexes. Differences in contaminant accumulations and lipid levels between sexes reflect variations in metabolic activity, reproductive costs, and adaptive strategies to seasonal changes and energy demands. This study highlights the importance of long-term monitoring to improve pollution management, environmental conservation, and the protection of marine organisms' health.

Key environmental parameters and numerical prediction model of jellyfish bloom in Qingchuan Bay Nuclear Power Plant, China

In recent years, there has been a notable increase in cooling water intake blockage caused by marine organism blooms at coastal nuclear power plants worldwide, resulting in shutdowns of nuclear power plants and large economic losses. A sizable portion of these incidents were caused by blooms from jellyfish, a planktonic invertebrate with a unique growth pattern. Suitable external conditions are conducive to the rapid growth of jellyfish, and blooms can occur within a few days. In order to better predict jellyfish bloom and enable nuclear power plants to prepare for it in advance, this study explores the numerical relationship between jellyfish biomass and environmental parameters. A series of time windows (evaluation intervals) were defined and constructed by a time-series recursive approach, which solved the problem of poor correlation between jellyfish biomass and environmental parameters at non-bloom points. The optimal time window length D = 10 was obtained, and the key environmental parameters affecting jellyfish biomass were screened as sea surface temperature, salinity, voltage value, dissolved oxygen, and chlorophyll. According to the ADF and KPSS tests, the key parameters have no significant time dependence, which ensures the stability and reliability of the subsequent predictions. The jellyfish bloom prediction model was derived by calculating the score F through the recursive Principal Component Analysis of the key environmental parameter in the time interval preceding the prediction point. The sudden change moments of score F correspond well to the jellyfish bloom moments, and the sudden change moments are all advanced for a period of time compared to the bloom time, which can provide valuable time for the nuclear power plant to organize manpower to deal with the blockage. Finally, a maximum score F threshold model was proposed to be coupled with the jellyfish bloom prediction model to provide a more robust basis for early warning of jellyfish at nuclear power plants.

A mass spectrometry database for the identification of marine animal saponin-related metabolites.

Saponins encompass a diverse group of naturally occurring glycoside molecules exhibiting amphiphilic properties and a broad range of biological activities. There is a resurgence of interest in those saponins produced by marine organisms based on their potential therapeutic benefits, application in food products and most recently their potential involvement in intra- and inter-species chemical communication. The continual advancements in liquid chromatography techniques and mass spectrometry technologies have allowed for greater detection rates, as well as improved isolation and elucidation of saponins. These factors have significantly contributed to the expansion in the catalogue of known saponin structures isolated from marine invertebrates; however, there currently exists no specific chemical library resource to accelerate the discovery process. In this study, a Marine Animal Saponin Database (MASD v1.0) has been developed to serve as a valuable chemical repository for known marine saponin-related data, including chemical formula, molecular mass and biological origin of nearly 1000 secondary metabolites associated with saponins produced by marine invertebrates. We demonstrate its application with an exemplar asteroid extract (Acanthaster cf. solaris, also known as crown-of-thorns starfish; COTS), identifying saponins from the MASD v1.0 that have been previously reported from COTS, as well as 21 saponins isolated from multiple other related asteroid species. This database will help facilitate future research endeavours, aiding researchers in exploring the vast chemical diversity of saponins produced by marine organisms and providing ecological insights, and the realisation of their potential for various applications, including as pharmaceuticals.

Marine plastic litter vs clean and living water

Marine plastic litter vs clean and living water Marine plastic pollution is a global crisis with increasing impacts on the environment, marine life, and human health. Multinational and national organisations are working to develop solutions that are accepted by all stakeholders connected to the marine environment and fishing industry. Marine plastic litter is harming marine ecosystems through ingestion, entanglement, and the possible release of toxic chemicals. A study from the North Sea showed that 93% of fulmar birds analysed had ingested plastic, with approximately 60% exceeding the 0.1 g level of plastic ingestion.

Quantifying the role of iron recycling by Adélie and Emperor penguins over the austral spring and summer in Prydz Bay

In large areas of the Southern Ocean, iron limits phytoplankton production. Although biologically mediated iron recycling has been studied for the higher trophic-level whales and the lower trophic-level krill, less is known of the numerically abundant seabirds foraging in Antarctic waters. In this study, we estimate the magnitude of iron recycled by two Antarctic breeding seabirds, the Adélie and emperor penguins, across the austral spring and summer in the Prydz Bay region, East Antarctica. Their contribution to iron recycling and associated pathways differs in line with their contrasting life history strategies (summer and winter breeding) and their breeding habitat (land and fast ice). We consider their breeding cycle in relation to their terrestrial activities compared to foraging periods at sea. High iron concentration (~419 mg kg−1) in guano of both penguin species suggests that they are a source of regenerated iron. Breeding emperor penguins supplied an average of 237 μmol iron m−2 day−1 on the fast ice that they breed on that eventually ends in the ocean when the ice melts completely in summer (November–February). During their foraging trips, the adult emperor penguins contribute between 7 × 10−5 and 4 × 10−4 μmol iron m−2 day−1, as their foraging ranges increase over the breeding season. In contrast, breeding Adélie penguins supplied between 254 and 1,243 μmol iron m−2 day−1 whilst at their colony, with a fraction of guano entering the ocean via meltwater flowing into the ocean. The flux decreases to 2 × 10−3 to 6 × 10−2 μmol iron m−2 d−1, whilst they are foraging. Our study finds that penguins redistribute a large flux of iron onto their colonies, which may enter the adjacent water through sea ice melt and facilitated through katabatic winds. Despite their high abundance in Prydz Bay, the contribution of penguins to iron flux during their foraging periods is minor, due to the enormous foraging range being covered. Further research into the bioavailability of iron by marine organisms coupled with parallel measurements of seawater iron concentration and phytoplankton uptake experiments will be invaluable in refining iron budgets in both this region and other hotspots along the Antarctic coast where higher trophic-level animals are abundant.

Comparative Analyses of Dynamic Transcriptome Profile of Heart Highlight the Key Response Genes for Heat Stress in Zhikong Scallop Chlamys farreri.

Heat stress resulting from global climate change has been demonstrated to adversely affect growth, development, and reproduction of marine organisms. The Zhikong scallop (Chlamys farreri), an important economical mollusk in China, faces increasing risks of summer mortality due to the prolonged heat waves. The heart, responsible for transporting gas and nutrients, is vital in maintaining homeostasis and physiological status in response to environmental changes. In this study, the effect of heat stress on the cardiac function of C. farreri was investigated during the continuous 30-day heat stress at 27 °C. The results showed the heart rate of scallops increased due to stress in the initial phase of high temperature exposure, peaking at 12 h, and then gradually recovered, indicating an acclimatization at the end of the experiment. In addition, the levels of catalase (CAT), superoxide dismutase (SOD), and total antioxidant capacity (T-AOC) exhibited an initial increase followed by recovery in response to heat stress. Furthermore, transcriptome analysis of the heart identified 3541 differentially expressed genes (DEGs) in response to heat stress. Subsequent GO and KEGG enrichment analysis showed that these genes were primarily related to signal transduction and oxidative stress, such as the phosphatidylinositol signaling system, regulation of actin cytoskeleton, MAPK signaling pathway, FoxO signaling pathway, etc. In addition, two modules were identified as significant responsive modules according to the weighted gene co-expression network analysis (WGCNA). The upregulation of key enzymes within the base excision repair and gap junction pathways indicated that the heart of C. farreri under heat stress enhanced DNA repair and maintained cellular integrity. In addition, the variable expression of essential signaling molecules and cytoskeletal regulators suggested that the heart of C. farreri modulated cardiomyocyte contraction, intracellular signaling, and heart rate through complex regulation of phosphorylation and calcium dynamics in response to heat stress. Collectively, this study enhances our understanding of cardiac function and provides novel evidence for unraveling the mechanism underlying the thermal response in mollusks.

Super-Tough, Non-Swelling Zwitterionic Hydrogel Sensor Based on the Hofmeister Effect for Potential Motion Monitoring of Marine Animals.

Hydrogel-based electronic devices in aquatic environments have sparked widespread research interest. Nevertheless, the challenge of developing hydrogel electronics underwater has not been profoundly surmounted because of the fragility and swelling of hydrogels in aquatic environments. In this work, a zwitterionic double network hydrogel comprisedof polyvinyl alcohol (PVA), poly(sulfobetaine methacrylate) (PSBMA), and sulfuric acid (H2SO4) demonstrates super-tough and non-swelling performance. The Hofmeister effect of H2SO4 and PSBMA induces the PVA chains to form numerous nanocrystalline domains, which serve as the primary physical crosslinking points and provide effective energy dissipation. H2SO4 induces a strong salting-out effect to facilitate PVA crystallization and the formation of a dense and stable network structure that inhibits swelling. The resulting hydrogel exhibits an ultra-high toughness of 4.61MJm-3, non-swelling, and long-term stability for up to a month in pure water and seawater. Based on this, a hydrogel-based seawater strain sensor has been developed to monitor the underwater movements of marine animal models. Reliable and stable sensing performance ensures real-time collection of underwater motion signals, despite the impacts of water flow and the interference of ions. This study provides a facile approach to designing super-tough and non-swelling hydrogels and further expands the application of underwater electronic devices.

Environmental weathering transforms plastic pollution

Environmental weathering transforms plastic pollution The prevalence of plastics in our daily lives is reflected by their ubiquity in nature. Jeffrey M. Farner from the FAMU-FSU College of Engineering, details how environmental weathering transforms plastic pollution. Due to use, improper disposal, and environmental transport, plastics are found globally, including in unpopulated locations. This pollution ranges from intact discarded items large enough to be choking hazards for marine life to particles at the nanometer scale. These smallest particles have been observed to translocate into animal tissues, raising concerns about toxicity. The concentrations of plastic particles vary widely, as do the morphology and other characteristics, but they exist.

Conversion of dehydrocoelenterazine to coelenterazine in mammalian cells: Identification using cultured cells stably expressing coelenterazine-utilizing luciferase

Dehydrocoelenterazine (dCTZ) is a dehydrogenated form of coelenterazine (CTZ), which is well-known as the luciferin responsible for the bioluminescence reaction in marine organisms. In this report, we demonstrate for the first time that dCTZ is readily reduced to CTZ in mammalian cells. Using an FDSS®/μCell functional drug screening system, the conversion of dCTZ to CTZ in cells was identified through the luciferin (CTZ)-luciferase reaction in Chinese hamster ovary K1 (CHO–K1) cell lines, which stably expressed CTZ-utilizing luciferases of Renilla luciferase (RLase) or QL-nanoKAZ (a mutant of the 19 kDa protein of Oplophorus luciferase). After loading dCTZ into CHO–K1 cells expressing RLase or QL-nanoKAZ, the luminescence from both cells was detected within 10 s and continued for over 30 min. Thus, dCTZ permeates mammalian cells and is immediately converted to CTZ. This suggests that dCTZ could potentially be used as a substitute for CTZ in in vivo assays of the CTZ-dependent luminescence systems.

Bioaccumulation potentials of per-and polyfluoroalkyl substances (PFAS) in recreational fisheries: Occurrence, health risk assessment and oxidative stress biomarkers in coastal Biscayne Bay

Per-and polyfluoroalkyl substances (PFAS) are a group of synthetic, highly fluorinated, and emerging chemicals that are reported to be used for both industrial and domestic applications. Several PFAS have demonstrated persistent, bioaccumulative and toxic tendencies in marine organisms. Therefore, this research aims to characterize and quantify these compounds in both recreational fisheries and surface water samples, including estimating their bioaccumulation potentials. In addition, we assessed the potential contribution of biomonitoring tools such as oxidative stressors and morphological index on fish and ecological health. Finally, human health risk assessment was performed based on available toxicological data on limited PFAS. All PFAS were detected in at least one sample except for N-EtFOSAA in lobster which was below the method detection limit. ƩPFAS body burden ranged from 0.15 to 3.40 ng/g wet weight (ww) in blackfin tuna samples and 0.37–5.15 ng/g ww in lobster samples, respectively. Wilcoxon rank paired test (α = 0.05) shows that there is statistical significance (ρ < 0.05) of ƩPFAS between species. Bioaccumulation factors (BAF) suggest an increasing trend in PFAS classes (PFCAs < PFSAs < FTSs), with higher BAFs observed in tuna compared to lobster. Long-chain PFESAs and FASAA were reported at higher concentrations in lobster compared to Blackfin tuna due to their bioavailability through sediment-sorption interactions. Although Fulton’s condition factor (FCF) indicates healthy fish conditions, oxidative stress biomarkers suggest that tuna and lobster might be under stress, which can weaken their immune system against exposure to emerging contaminants such as PFAS. Hazard risk (HR) suggests a low risk to human health based on the consumption of the studied species; however, the risk of contaminant exposure may be higher than estimated. This study is aimed at improving food safety by providing better understanding of how PFAS infiltrate into human diet and incorporating data on influence of contaminant exposure and environmental stressors on marine health.

The flyway construct and assessment of offshore wind farm impacts on migratory marine fauna

Abstract The flyway construct was developed in the 1930s to protect networks of bird stopover habitats along annual migration circuits. Here flyway is conceived as a quantifiable vector, a construct of the seasonal velocity and the geographic route taken among networked habitats, generalizable among marine migratory animals, and a way forward in assessing regional offshore wind (OW) development impacts. OW development in the South and East China Sea, North Sea, and US Mid-Atlantic Bight will result in thousands of offshore wind turbines that transect coastal and shelf flyways, not only for birds but also for fishes, sea turtles, and marine mammals. With increased capacity to fully measure the extent and dynamics of migrations through electronic tracking and observing systems, avian-like behaviors are apparent for whales, turtles, and fishes, such as stopover behaviors, migration synchrony, and partial migration. Modeled northwest Atlantic flyways (migration vectors) for northern gannets, striped bass, and North Atlantic right whale quantified seasonal speed, persistence, and variance during seasonal migration phases. From these flyway models, a series of flyway metrics are proposed that lend themselves to hypothesis-testing, dynamic habitat models, and before–after impact assessment. The flyway approach represents a departure from current impact designs, which are dominated by local OW farm studies and, at regional dimensions, survey-based (Eulerian) data structures (overlap models). As a next step, we encourage colleagues to develop flyway databases and test flyway hypotheses for model species.

Polyamine impact on physiology of early stages of reef-building corals-insights from rearing experiments and RNA-Seq analysis.

Polyamines are involved in various functions related to the cellular-level responses. To assess effects of polyamines on marine organisms, rearing experiments and comprehensive gene expression analyses were conducted on Acropora digitifera and Acropora sp.1, representative reef-building corals along the west-central coast of Okinawa, Japan, to evaluate effects of putrescine. Concentrations of putrescine ≥ 1mM dissolved tissues of juvenile polyps and increased mortality of planula larvae. RNA-Seq analysis of juvenile polyps exposed to putrescine at the stage before effects became visible revealed dynamic fluctuations in gene expression in the putrescine-treated samples, with increased expression of stress-responsive genes (e.g. NAD-dependent protein deacylase sirtuin-6) and the polyamine transporter Slc18b1-like protein. These results also suggest that putrescine affects expression of genes related to ribosomes and translation. This study provides important insights into roles of polyamines and future directions regarding physiological responses of corals.

New Insights into the Mechanisms of Toxicity of Aging Microplastics.

Nowadays, synthetic polymer (plastic) particles are ubiquitous in the environment. It is known that for several decades microplastics (MPs) have been accumulating in the World Ocean, becoming available to a large variety of marine organisms. Particularly alarming is the accumulation of aging plastic particles, as the degradation processes of such particles increase their toxicity. The diverse display of negative properties of aging MPs and its effect on biota are still poorly understood. In this study, in vitro experiments modeling the interaction of pristine and UV-irradiated aging polypropylene (PP) fragments with hemocytes and mitochondria of bivalve mollusks Mytilus sp. were performed. The appearance of free radicals in the environment was recorded by spectral characteristics of indicator dyes-methylene blue (MB) and nitroblue tetrazolium (NBT). It was found that due to photooxidation, aging PP fragments sorbed more than threefold MB on their modified surface compared to pristine samples of this polymer. Using NBT, the formation of reactive oxygen species in seawater in the presence of pristine and photoactivated PP was recorded. It was also found that photodegraded PP fragments largely stimulated the development of lipid peroxidation processes in mitochondrial membranes and reduced the stability of hemocyte lysosome membranes compared to pristine PP fragments. In general, the results obtained concretize and supplement with experimental data the previously stated hypothesis of toxicity of aging MPs.

Sea fans and their associated fauna in the marine animal forests of Burdwood Bank at 54°S, SW Atlantic Ocean

Sea fans and their associated fauna in the marine animal forests of Burdwood Bank at 54°S, SW Atlantic Ocean