Microplastic volumes in Tokyo Bay.

Microplastic (MP) pollution is a rising environmental concern. This study investigated MP concentrations in Tokyo Bay using neuston net for surface sampling and deep-sea plankton pump for underwater sampling across six stations at multiple depths. Results revealed substantial variation in MP concentrations.

An automatic method for accurate signal-to-noise ratio estimation and baseline correction of Raman spectra of environmental microplastics.

In this study, we introduced a k-iterative double sliding-window (DSW^k) method for the estimation of spectral noise, signal-to-noise ratio (SNR), and baseline correction. The performance was evaluated using simulated spectra and compared against other commonly employed methods. Convergent evaluation determined that a k value of 20 strikes an optimal balance between convergence and computational intensity.

Are yessotoxins an emerging problem in Chile? Context and perspectives following the first report of YTX levels exceeding the regulatory limit in the Patagonian fjord system.

In late summer and early autumn 2022, an intense bloom of Protoceratium reticulatum-the main yessotoxin (YTX) producer along Chilean coasts and a major threat to artisanal fisheries, the aquaculture industry, and environmental health-was recorded in the Patagonian fjord system. The high YTX levels (>3.75 mg kg) resulted in the first ban of shellfish collection in Chile.

Intraspecific variations in oyster (Magallana gigas) ploidy does not affect physiological responses to microplastic pollution.

Recent advances in genetic manipulation such as triploid breeding and artificial selection, have rapidly emerged as valuable hatchery methodologies for enhancing seafood stocks. The Pacific oyster Magallana gigas is a leading aquaculture species worldwide and key ecosystem engineer that has received particular attention in this field of science. In light of the growing recognition of the ecological effects of intraspecific variation, oyster polyploids provide a valuable opportunity to assess whether intraspecific diversity affects physiological responses to environmental stressors.

Cryopreservation of the whole testes of Asian sea bass (Lates calcarifer) and its effects on apoptosis, germ cell-specific gene expression, germ cell transplantability, and DNA methylation.

Cryopreservation of spermatogonia could be a useful tool to preserve the genetic resources of fish, which could be further restored via germ cell transplantation. In this study, the protocol for the cryopreservation of the spermatogonia of Asian sea bass (Lates calcarifer), an economically important fishery resource in the Indo-West Pacific, was optimised. The impact of the cryopreservation technique on cell viability and apoptosis, expression of several genes related to immature germ cell markers, transplantability in allogeneic recipients, and global DNA methylation was evaluated.

Ovalbumin/sodium alginate Pickering emulsion: Structural characteristics and its contribution to enhancing the gel properties of Hairtail (Trichiurus haumela) surimi.

In this study, ovalbumin (OV) and sodium alginate (SA), two macromolecular complexes, were coagulated into the emulsifier (OV/SA), which stabilized soybean oil by electrostatic interaction, hydrophobic interactions, and hydrogen bonding. The structure of OV/SA and properties of OV/SA Pickering emulsion were investigated. Additionally, the effect of emulsions on the gel and protein properties of hairtail surimi was studied.

Application of nervous necrosis virus capsid protein-based antigen-presenting particles for vaccine development.

Nervous necrosis virus (NNV) capsid protein plays an important role in producing viral particles without any genetic elements. Thus, NNV is a promising candidate for vaccine development and is widely used for constructing vaccines, including DNA, recombinant proteins, and virus-like particles (VLPs). Our study aimed to investigate the potential of NNV capsid protein (NNV) and NNV capsid protein fused to enhanced green fluorescent protein (NNV-EGFP) through VLP formation and whether their application can induce specific antibody responses against certain antigens.

Morphologically controlled synthesis of MgFe-LDH using MgO and succinic acid for enhanced arsenic adsorption: Kinetics, equilibrium, and mechanism studies.

In this study, we investigated improving the performance of a layered double hydroxide (LDH) for the adsorption of As(III) and As(V) by controlling the morphology of LDH crystals. The LDH was synthesized via a simple coprecipitation method using barely soluble MgO as a precursor and succinic acid (SA) as a morphological control agent. Doping the LDH crystals with carboxylate ions (RCOO) derived from SA caused the crystals to develop in a radial direction.

Element cycling and microbial life in the hadal realm.

Hadal trenches represent the deepest oceanic realm and were once considered to be deprived of life. However, trenches act as important depocenters for organic matter with highly elevated microbial activity. In this forum, we discuss the biogeochemistry of the hadal realm and its microbial communities thriving at extreme hydrostatic pressure.

Steady nutrient upwelling around a biological hotspot of the confluence between the quasi-stationary jet and the Oyashio in the western North Pacific.

The quasi-stationary jet, a branch of the Kuroshio Extension, transports warm saline water in the mixed water region of the western North Pacific. Around the subarctic front between the quasi-stationary jet and Oyashio and its downstream area is a biologically productive area including small pelagic fishes. However, how nutrient is supplied to the euphotic zone in this region remains elusive, especially into the quasi-stationary jet.

The Influence of Simulated Organic Matter on the Inactivation of Viruses: A Review.

Viruses impose a significant public health burden globally, and one of the key elements in controlling their transmission is the ability to inactivate them using disinfectants. However, numerous challenges to inactivating foodborne viruses exist due to inherent viral characteristics (such as recalcitrance to commonly used inactivation agents) and external factors (such as improper cleaning before application of inactivation agent, improper contact time, etc.).

A sedimentary DNA record of the Atacama Trench reveals biodiversity changes in the most productive marine ecosystem.

The hadopelagic environment remains highly understudied due to the inherent difficulties in sampling at these depths. The use of sediment environmental DNA (eDNA) can overcome some of these restrictions as settled and preserved DNA represent an archive of the biological communities. We use sediment eDNA to assess changes in the community within one of the world's most productive open-ocean ecosystems: the Atacama Trench.

Development of a ship-based camera monitoring system for floating marine debris.

This study developed an automatic monitoring system for Floating Marine Debris (FMD) aimed at reducing the labor-intensiveness of traditional visual surveys. It involved creating a comprehensive FMD database using 55.6 h of video footage and numerous annotated images, which facilitated the training of a deep learning model based on the YOLOv8 architecture.

Investigating the impact of chlorine dioxide in shrimp-rearing water on the stomach microbiome, gill transcriptome, and infection-related mortality in shrimp.

Aims: This study aimed to assess the effects of chlorine dioxide (ClO2) in water on whiteleg shrimp Penaeus vannamei, evaluating its impact on the stomach microbiota, gill transcriptome, and pathogens.

Methods And Results: ClO2 was added to the aquarium tanks containing the shrimp. The application of ClO2 to rearing water was lethal to shrimp at concentrations above 1.

Systemic immune responses do not affect significant immune responses in the skin.

Fish skin plays an important role in defending against pathogens in water, primarily through the secretion of skin mucus containing various immune-related factors. Local immune responses in the skin activate systemic immune responses by inflammatory cytokines. However, it remains unclear whether immune responses in the skin occur after systemic immune responses caused by pathogen invasion into the fish body.

Construction and antibacterial activities of walnut green husk polysaccharide based silver nanoparticles (AgNPs).

In this paper, the size-controllable nano‑silver particles (AgNPs) were synthesized from walnut green husk polysaccharide, and its cytotoxicity and antibacterial activity were evaluated. Firstly, acidic polysaccharide WGHP2 was extracted from walnut green husk, and then the silver ion in AgNO was reduced in WGHP2 aqueous solution using NaBH, so as to synthesize the nano‑silver composite. The nano‑silver composite was characterized by transmission electron microscope, Fourier infrared spectroscopy, ultraviolet-visible spectrometer, scanning electron microscope, inductively coupled plasma mass spectrometry and X-ray photoelectron spectroscopy.

Doxycycline pharmacokinetics and tissue depletion in striped catfish (Pagasianodon hypophthalmus) after oral administration.

The pharmacokinetics and residue depletion of doxycycline (DOX) in striped catfish (Pagasianodon hypophthalmus) after oral dosage were investigated. The pharmacokinetic experiment was conducted in an aquarium, while the experiment of residue depletion was performed in both an aquarium and earth ponds. Medicated feed was administered orally using the gavage method at a dosage of 20 mg/kg body weight.

Formation of marine oil snow by soot particles generated from burning of oils.

This study aims to investigate the interactions between marine oil snow (MOS) formation and soot particles derived from two distinct oils: condensate and heavy oil. Experimental findings demonstrate that the properties of oil droplets and soot particles play a key role in MOS formation. Peak MOS formation is observed within the initial days for condensate, while for heavy oil, peak formation occurs at a later stage.

Empirical validation of integrated stock assessment models to ensuring risk equivalence: A pathway to resilient fisheries management.

The Precautionary Approach to Fisheries Management requires an assessment of the impact of uncertainty on the risk of achieving management objectives. However, the main quantities, such as spawning stock biomass (SSB) and fish mortality (F), used in management metrics cannot be directly observed. This requires the use of models to provide guidance, for which there are three paradigms: the best assessment, model ensemble, and Management Strategy Evaluation (MSE).

Vitrification of medaka whole testis with a trehalose-containing solution and production of medaka individuals derived from the vitrified cells.

The cryopreservation of teleost eggs and embryos remains challenging, and there are no previous reports that demonstrate successful cryopreservation in medaka (Oryzias latipes). We have reported egg and sperm production, followed by the generation of donor-derived offspring by transplanting vitrified whole testes-derived testicular cells into surrogate fish. The vitrification solutions contained ethylene glycol, sucrose, and ficoll.

Validation of a New Liquid Asymmetric-Electrode Plasma Optical Emission Spectroscopy (LAEP-OES) Method for Measurement of Total Mercury in Tuna.

Background: Mercury intake is caused by eating seafood, such as tuna and other predatory fish species. To reduce the health risks of mercury intake, it is necessary to continuously measure and monitor mercury concentrations at fish farms and markets. We have developed a compact system that can detect multiple heavy metals by liquid asymmetric-electrode plasma optical emission spectroscopy (LAEP-OES).

Symbiotic endolithic microbes reduce host vulnerability to an unprecedented heatwave.

Heatwaves are increasingly severe and frequent, posing significant threats to ecosystems and human well-being. Characterised by high thermal variability, intertidal communities are particularly vulnerable to heat stress. Microbial endolithic communities that are found in marine calcifying organisms have been shown to induce shell erosion that alters shell surface colour, lowering body temperatures and increasing survival rates.

Freshwater spreading far offshore the Japanese coast.

River discharge to the ocean influences the transport of salts and nutrients and is a source of variability in water mass distribution and the elemental cycle. Recently, using an underwater glider, we detected thick, low-salinity water offshore for the first time, probably derived from coastal waters, in the central-eastern Sea of Japan, whose primary productivity is comparable to that of the western North Pacific. Thereafter, we aimed to investigate the offshore advection and diffusion of coastal water and its variability and assess their impact.