Marine Molluscs Research Articles

Effects of elevated temperature on 8-OHdG expression in the American oyster (Crassostrea virginica): Induction of oxidative stress biomarkers, cellular apoptosis, DNA damage and γH2AX signaling pathways

Global temperature is increasing due to anthropogenic activities and the effects of elevated temperature on DNA lesions are not well documented in marine organisms. The American oyster (Crassostrea virginica, an edible and commercially important marine mollusk) is an ideal shellfish species to study oxidative DNA lesions during heat stress. In this study, we examined the effects of elevated temperatures (24, 28, and 32 °C for one-week exposure) on heat shock protein-70 (HSP70, a biomarker of heat stress), 8‑hydroxy-2′-deoxyguanosine (8-OHdG, a biomarker of pro-mutagenic DNA lesion), double-stranded DNA (dsDNA), γ-histone family member X (γH2AX, a molecular biomarker of DNA damage), caspase-3 (CAS-3, a key enzyme of apoptotic pathway) and Bcl-2-associated X (BAX, an apoptosis regulator) protein and/or mRNA expressions in the gills of American oysters. Immunohistochemical and qRT-PCR results showed that HSP70, 8-OHdG, dsDNA, and γH2AX expressions in gills were significantly increased at high temperatures (28 and 32 °C) compared with control (24°C). In situ TUNEL analysis showed that the apoptotic cells in gill tissues were increased in heat-exposed oysters. Interestingly, the enhanced apoptotic cells were associated with increased CAS-3 and BAX mRNA and/or protein expressions, along with 8-OHdG levels in gills after heat exposure. Moreover, the extrapallial (EP) fluid (i.e., extracellular body fluid) protein concentrations were lower; however, the EP glucose levels were higher in heat-exposed oysters. Taken together, these results suggest that heat shock-driven oxidative stress alters extracellular body fluid conditions and induces cellular apoptosis and DNA damage, which may lead to increased 8-OHdG levels in cells/tissues in oysters.

Transgenerational transfer of the microbiome is altered by ocean acidification in oyster larvae

Ocean acidification will affect marine molluscs, however, transgenerational plasticity (TGP) can ameliorate some effects. Marine molluscs acquire members of their microbiome via the egg, yet we know little about how the microbiome can be influenced by transgenerational exposure to ocean acidification. We exposed adult Sydney Rock oysters (Saccostrea glomerata) from four genotypes to elevated and ambient PCO2 for nine weeks. Larvae were then raised in the same ambient and elevated PCO2 conditions. The relative abundance of bacteria in eggs and larvae were characterised using 16S RNA amplicon sequencing. Parental exposure to elevated PCO2 significantly altered the bacterial community composition of both eggs and larvae, but this was dependent on genotype. Parental exposure to elevated PCO2 caused five core Rhodobacteraceae ASVs to increase in relative abundance, and three Rhodobacteraceae ASVs to decrease in relative abundance. These findings show transfer of maternal microbiomes to larvae is altered by exposure to ocean acidification and this may play a role in TGP.

Albian ferns of the Partizansk Coal Basin (Primorsky Krai, Russian Far East)

A taxonomic study of Albian ferns from the Partizansk Coal Basin of Primorsky Krai was carried out. The Albian Age was an important stratigraphic milestone, when the Early Cretaceous flora changed to the Late Cretaceous flora. It was revealed that typical Mesozoic Onychiopsis predominated in taphocenoses, and representatives of young and evolutionarily advanced taxa Asplenium, Birisia appeared. The taxonomic composition of ferns in the Albian taphocenoses was almost constant from north to south. The vegetation of the Partizansk Basin occupied the coastal plain during Albian time, which was confirmed by the remains of marine and freshwater mollusks, phytofossils, as well as fish.

Conus regius-Derived Conotoxins: Novel Therapeutic Opportunities from a Marine Organism.

Conus regius is a marine venomous mollusk of the Conus genus that captures its prey by injecting a rich cocktail of bioactive disulfide bond rich peptides called conotoxins. These peptides selectively target a broad range of ion channels, membrane receptors, transporters, and enzymes, making them valuable pharmacological tools and potential drug leads. C. regius-derived conotoxins are particularly attractive due to their marked potency and selectivity against specific nicotinic acetylcholine receptor subtypes, whose signalling is involved in pain, cognitive disorders, drug addiction, and cancer. However, the species-specific differences in sensitivity and the low stability and bioavailability of these conotoxins limit their clinical development as novel therapeutic agents for these disorders. Here, we give an overview of the main pharmacological features of the C. regius-derived conotoxins described so far, focusing on the molecular mechanisms underlying their potential therapeutic effects. Additionally, we describe adoptable chemical engineering solutions to improve their pharmacological properties for future potential clinical translation.

What is conservation paleobiology? Tracking 20 years of research and development

Conservation paleobiology has coalesced over the last two decades since its formal coining, united by the goal of applying geohistorical records to inform the conservation, management, and restoration of biodiversity and ecosystem services. Yet, the field is still attempting to form an identity distinct from its academic roots. Here, we ask a deceptively simple question: What is conservation paleobiology? To track its development as a field, we synthesize complementary perspectives from a survey of the scientific community that is familiar with conservation paleobiology and a systematic literature review of publications that use the term. We present an overview of conservation paleobiology’s research scope and compare survey participants’ perceptions of what it is and what it should be as a field. We find that conservation paleobiologists use a variety of geohistorical data in their work, although research is typified by near-time records of marine molluscs and terrestrial mammals collected over local to regional spatial scales. Our results also confirm the field’s broad disciplinary basis: survey participants indicated that conservation paleobiology can incorporate information from a wide range of disciplines spanning conservation biology, ecology, historical ecology, paleontology, and archaeology. Finally, we show that conservation paleobiologists have yet to reach a consensus on how applied the field should be in practice. The survey revealed that many participants thought the field should be more applied but that most do not currently engage with conservation practice. Reflecting on how conservation paleobiology has developed over the last two decades, we discuss opportunities to promote community cohesion, strengthen collaborations within conservation science, and align training priorities with the field’s identity as it continues to crystallize.

Neither slugs nor snails: a molecular reappraisal of the gastropod family Velutinidae

AbstractThe systematics of the marine mollusc family Velutinidae has long been neglected by taxonomists, mainly because their often internal and fragile shells offer no morphological characters. Velutinids are usually undersampled owing to their cryptic mantle coloration on the solitary, social or colonial ascidians on which they feed and lay eggs. In this study, we address the worldwide diversity and phylogeny of Velutinidae based on the largest molecular dataset (313 specimens) to date, accounting for > 50% of the currently accepted genera, coupled with morphological and ecological data. Velutinids emerge as a diverse group, encompassing four independent subfamily-level lineages, two of which are newly described herein: Marseniopsinae subfam. nov. and Hainotinae subfam. nov. High diversity was found at genus and species levels, with two newly described genera (Variolipallium gen. nov. and Pacifica gen. nov.) and ≥ 86 species in the assayed dataset, 58 of which are new to science (67%). Velutinidae show a remarkable morphological plasticity in shell morphology, mantle extension and chromatic patterns. This variability is likely to be the result of different selective forces, including habitat, depth and trophic interactions.

Simultaneous determination of 13 paralytic shellfish toxins and tetrodotoxin in marine shellfish by porous graphitic carbon solid-phase extraction and hydrophilic interaction chromatography-tandem mass spectrometry

The lethal neurotoxins, paralytic shellfish toxins (PSTs), and tetrodotoxin (TTX) have recently been found in marine shellfish from many coastal states. Herein, we applied a sensitive and reliable ultra-performance hydrophilic interaction chromatography (HILIC)-tandem mass spectrometry (MS) method to determine 13 PSTs and TTX in marine shellfish using a porous carbon solid-phase extraction (SPE). This in-house validation study required the development of a novel chromatographic separation using a HILIC-Z column, which was necessary to retain highly polar compounds. Using acetonitrile as the organic phase and ammonium formate-formic acid buffer as the aqueous phase, the quantitative analysis was carried out with an external standard method in the multiple reaction monitoring modes using positive electrospray ionization. To reduce interference, 1% aqueous acetic acid extracts of the shellfish samples were cleaned up by ion-pair SPE using a porous graphitic carbon cartridge. The calibration curves for PSTs and TTX were linear (R 2 > 0.995), and the sensitivity was good, with limits of detection (LODs) of 1.7–13.7 µg/kg, and limits of quantitation (LOQs) of 5.2–41.0 µg/kg. The recoveries were 76.5–95.5% with RSDs of 3.1–12.0%. Finally, We applied the method for the determination of PSTs and TTX in three batches of Nassarius showing excellent method accuracy against expected values.

Обращаясь к богам и предкам: горны из морских раковин как ритуальные инструменты у древних майя

The use of trumpets made from the conch shells of large marine mollusks was one of the peculiar traits of Mesoamerican culture. The earliest evidence of this practice can be placed in the Middle Formative (I mil. BC), but this tradition persisted among the native population of Mexico until the 20 th century. Conch shell trumpets were excavated in many Maya sites (Uaxactun, Kaminaljuyu, Mayapan, Tikal, Dzibilchaltun etc.). Since the 1960s it was believed that their main function was that of alarm, and sometimes they were considered as a type of musical instruments. The analysis of previously unpublished hieroglyphic inscription on the conch shell from Asunción Mita (Department of Jutiapa, Guatemala) preserved in the National Museum of Archaeology and Ethnology of Guatemala shows that it was used in the ceremony of appeal to the deities. New interpretation of the hieroglyphic texts on the Early Classic conch shells leads to the conclusion that, in the Classic Maya culture, their main function was ritual. They served as one of the main instruments of the ritual communication with the deities and ancestors, whose names and images were inscribed on the conch shells.

Ecological significance of G protein-coupled receptors in the Pacific oyster (Crassostrea gigas): Pervasive gene duplication and distinct transcriptional response to marine environmental stresses.

Marine ecosystems with ocean warming and industry pollution threaten the survival and adaptation of organisms. G protein-coupled receptors (GPCRs) play critical roles in various physiological and toxicological processes in vertebrates and invertebrates. The Pacific oyster (Crassostrea gigas) was widely used to study the adaptation of marine molluscs to coastal environments. In this work, we identified a total of 586 GPCRs in C. gigas genome. The C. gigas GPCRs were divided into five classes (including class A, B, C, E and F) with different degrees of expansion. Meta-analysis of multiple RNA-seq datasets revealed that transcriptional expression patterns of GPCRs in C. gigas were distinct in response to high temperature, salinity, air exposure, heavy metal, ostreid herpes virus 1 (OsHV-1) and Vibrio challenge. This work for the first time characterized the GPCR gene family and provided insights into the potential roles of GPCRs in adaptation of marine molluscs to stressful coastal environment.

Inventory of marine molluscs in Gulf of Oran (Western Algerian coastline)

Inventory of marine molluscs in Gulf of Oran (Western Algerian coastline)

The Marine Mollusca of Cyprus (by October 2022): An Up-to-date, Systematic Catalogue, Documented with Bibliographic and Pictorial References

The present study contributes with an updated, systematic catalogue documented with bibliographic and pictorial references on the present marine Mollusca of the Cypriot Seas by October 2022. It includes 753 species belonging to 184 families and enriches the relevant malacofauna by some 8%. The up-to-date nomenclature is based on the WoRMS Database.

Toxicity of Persian Gulf shell-less marine mollusc (Peronia peronii) methanolic extract on melanoma tumor mitochondria

Introduction Melanoma is known as an aggressive and highly lethal cancer. The poor prognosis and resistance to treatment are characteristics of melanoma. In melanoma cells, apoptosis signaling which relies heavily on the acute activity of mitochondria and reactive oxygen species (ROS) formation is suppressed. Studies have shown that compounds isolated from marine herbs and animals, have been shown to have cytotoxic consequences on cancerous cells in prior research. This study was designed to evaluate the apoptotic effect of methanolic extract of Persian Gulf shell-less marine mollusc (Peronia peronii) on skin mitochondria isolated from animal model of melanoma. Purpose Melanoma mitochondria obtained from skin of melanoma animal model are studied in this research to see whether extracts from Persian Gulf shell-less marine mollusc (Peronia peronii), has a cytotoxic impact on them. Material and method In this study, the mitochondria were isolated from melanoma cells via differential centrifugation were treated with various concentrations (650, 1300 and 2600 µg/ml) of methanolic extract of Peronia peronii. Then MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) viability assay, Reactive oxygen species (ROS) determination, Mitochondrial Membrane Potential (MMP) decline assay, mitochondrial swelling and cytochrome c release determination were performed. Flow cytometry assay of % apoptotic vs necrotic phenotypes was also performed on extract treated melanoma cells. Results The results of MTT assay showed that different concentrations of Peronia peronii extract significantly (P < 0.05) decreased the SDH activity in cancerous skin mitochondria with the IC50(1300 μg/ml). The ROS results also showed that all concentrations of Peronia peronii extracts significantly increased ROS production, MMP decline and the release of cytochrome c in cancer groups mitochondria. The swelling of mitochondria was significantly increased compared to the control group. In addition, the results of apoptosis assay showed that addition of root extract of Peronia peronii on melanoma cells increased apoptosis, while it had no effect on control non tumour cells. Discussion and conclusion Based on these results, the presence of potentially bioactive compounds in Peronia peronii make this Persian Gulf coastal herb a strong candidate for further molecular studies and clinical research in the field of melanoma cancer therapy.

A novel protein CtCBP-1 functions as a crucial macromolecule during mineralization of limpet teeth

Limpets are a class of marine mollusks that use mineralized teeth, one of the hardest and strongest biological materials, to feed on algae on rocks. By combining proteomics and RNA-seq analysis of limpet radula, we identified a novel chitin-binding protein (CtCBP-1) that may play a regulatory role in radula mineralization of Cellana toreuma. In this study, the full-length cDNA of CtCBP-1 gene was cloned for the first time, and the protein was successfully expressed in vitro. In vitro experiments demonstrated that CtCBP-1 binds well to both goethite and chitin, which are key components of the cusp. We studied the function of CtCBP-1 on goethite crystallization in vitro, revealing that it changed the morphology of goethite crystals. We also used fluorescence higher resolution imaging to map the binding of CtCBP-1 in radula and found that the distribution of CtCBP-1 on radula was specific, which consistent with the SEM results finding tightly aligned goethite. In this study, a novel protein CtCBP-1, which regulates the distinctive biomineralization process of limpet teeth, is identified for the first time. This protein’s identification may inform biomimetic techniques for creating hard materials that can withstand ambient temperature.

Molecular and biochemical responses to tributyltin (TBT) exposure in the American oyster: Triggers of stress-induced oxidative DNA damage and prooxidant-antioxidant imbalance in tissues by TBT

Environmental pollution increases due to anthropogenic activities. Toxic chemicals in the environment affect the health of aquatic organisms. Tributyltin (TBT) is a toxic chemical widely used as an antifouling paint on boats, hulls, and ships. The toxic effect of TBT is well documented in aquatic organisms; however, little is known about the effects of TBT on DNA lesions in shellfish. The American oyster (Crassostrea virginica, an edible and commercially important species) is an ideal marine mollusk to examine the effects of TBT exposure on DNA lesions and oxidative/nitrative stress. In this study, we investigated the effects of TBT on 8′-hydroxy-2′-deoxyguanosine (8-OHdG, a biomarker of pro-mutagenic DNA lesion), double-stranded DNA (dsDNA), dinitrophenyl protein (DNP, a biomarker on reactive oxygen species, ROS), 3-nitrotyrosine protein (NTP, a biomarker of reactive nitrogen species, RNS), catalase (CAT, an antioxidant), and acetylcholinesterase (AChE, a cholinergic enzyme) expressions in the gills and digestive glands of oysters. We also analyzed extrapallial (EF) fluid conditions. Immunohistochemical and qRT-PCR results showed that TBT exposure significantly increased 8-OHdG, dsDNA, DNP, NTP, and CAT mRNA and/or protein expressions in the gills and digestive glands. However, AChE mRNA and protein expressions, and EP fluid pH and protein concentrations were decreased in TBT-exposed oysters. Taken together, these results suggest that antifouling biocide-induced production of ROS/RNS results in DNA damage, which may lead to decreased cellular functions in oysters. To the best of our knowledge, the present study provides the first molecular/biochemical evidence that TBT exposure results in oxidative/nitrative stress and DNA lesions in oysters.

Light entrainment and molecular regulation of the circadian clock in razor clam Sinonovacula constricta

Sinonovacula constricta is an important bivalve with strong photosensitivity and a robust circadian rhythm. To elucidate the light entrainment of the molecular circadian clock in this species, this study identified the clock genes, characterized their tissue distribution, and investigated their transcriptional variations under different light regimes: LD (12 h light/12 h dark cycle), LL (continuous light), and DD (continuous dark). The results showed that the S. constricta clock system consists of seven genes [Circadian locomotor output cycles kaput (ScClock), Brain and muscle ARNT-like protein (ScBmal), Cryptochrome (ScCry1 and 2), Period (ScPer), and Timeless (ScTimeless1 and 2)] that are closely related to their orthologs in marine mollusks and contained corresponding conserved functional regions, indicating the conserved evolution of the circadian clock among organisms. These genes were expressed in all tissues, with high expression in the labial palps and hepatopancreas, suggesting a complex peripheral biological clock in S. constricta and the critical role of these two tissues in circadian functions. When exposed to different light regimes in labial palps, genes from the positive loop (ScClock and ScBmal) displayed a daily/circadian rhythm under both LD and DD and their acrophases were shifted by 5–7 h, whereas genes from the negative loop displayed daily rhythms (ScCry1 and ScPer) under LD and circadian rhythms (ScCry2 and ScTimeless2) under DD. However, only one gene (ScTimeless2) displayed a circadian rhythm under LL conditions. These results suggest that the S. constricta circadian system may be regulated by different clock genes to adapt to various light environments. Although similar phenomena were observed in the hepatopancreas, markedly different clock gene expression patterns occurred between the two tissues, indicating a tissue-specific regulated circadian system. Collectively, this study reveals how the circadian oscillators of S. constricta respond to light and may promote light environment optimization in the S. constricta farming industry.

Variational and phase response analysis for limit cycles with hard boundaries, with applications to neuromechanical control problems

Motor systems show an overall robustness, but because they are highly nonlinear, understanding how they achieve robustness is difficult. In many rhythmic systems, robustness against perturbations involves response of both the shape and the timing of the trajectory. This makes the study of robustness even more challenging. To understand how a motor system produces robust behaviors in a variable environment, we consider a neuromechanical model of motor patterns in the feeding apparatus of the marine mollusk Aplysia californica (Shaw et al. in J Comput Neurosci 38(1):25–51, 2015; Lyttle et al. in Biol Cybern 111(1):25–47, 2017). We established in (Wang et al. in SIAM J Appl Dyn Syst 20(2):701–744, 2021. https://doi.org/10.1137/20M1344974) the tools for studying combined shape and timing responses of limit cycle systems under sustained perturbations and here apply them to study robustness of the neuromechanical model against increased mechanical load during swallowing. Interestingly, we discover that nonlinear biomechanical properties confer resilience by immediately increasing resistance to applied loads. In contrast, the effect of changed sensory feedback signal is significantly delayed by the firing rates’ hard boundary properties. Our analysis suggests that sensory feedback contributes to robustness in swallowing primarily by shifting the timing of neural activation involved in the power stroke of the motor cycle (retraction). This effect enables the system to generate stronger retractor muscle forces to compensate for the increased load, and hence achieve strong robustness. The approaches that we are applying to understanding a neuromechanical model in Aplysia, and the results that we have obtained, are likely to provide insights into the function of other motor systems that encounter changing mechanical loads and hard boundaries, both due to mechanical and neuronal firing properties.

Properties of Protein Isolates from Marine Hydrobionts Obtained by Isoelectric Solubilisation/Precipitation: Influence of Temperature and Processing Time.

Protein isolates were obtained from marine hydrobionts by the method of isoelectric precipitation with a preliminary stage of protein alkaline solubilisation. Northern blue whiting was chosen as the raw material. Various technological modes of the solubilisation stage were used: the temperature of the reaction mixture was 4 or 20 °C, and the duration was 4 or 16 h. The yield of the product was 44-45% with a high content of the main component (protein) equal to about 95%. It has been shown that a decrease in the temperature and duration of the alkaline solubilisation stage provides the production of protein isolates with good technological properties, a low solubility, high swelling and high emulsifying ability, necessary for its use in the production of functional food products, including therapeutic and prophylactic effects. These technological properties are explained by a change in the composition and structure of the protein, the change being an increase in the content of essential amino acids and the proportion of α-helices in the polypeptide chain. The main patterns obtained will be used to obtain protein isolates from marine molluscs.

Structural and evolutionary insights into the multidomain galectin from the red abalone Haliotis rufescens with specificity for sulfated glycans

Galectins are an evolutionarily ancient family of lectins characterized by their affinity for β-galactosides and a conserved binding site in the carbohydrate recognition domain (CRD). These lectins are involved in multiple physiological functions, including the recognition of glycans on the surface of viruses and bacteria. This feature supports their role in innate immune responses in marine mollusks. Here, we identified and characterized a galectin, from the mollusk Haliotis rufescens (named HrGal), with four CRDs that belong to the tandem-repeat type. HrGal was purified by affinity chromatography in a galactose-agarose resin and exhibited a molecular mass of 64.11 kDa determined by MALDI-TOF mass spectrometry. The identity of HrGal was verified by sequencing, confirming that it is a 555 amino acid protein with a mass of 63.86 kDa. This protein corresponds to a galectin reported in GenBank with accession number AHX26603. HrGal is stable in the presence of urea, reducing agents, and ions such as Cu2+ and Zn2+. The recombinant galectin (rHrGal) was purified from inclusion bodies in the presence of these ions. A theoretical model obtained with the AlphaFold server exhibits four non-identical CRDs, with a β sandwich folding and the representative motifs for binding β-galactosides. This allows us to classify HrGal within the tandem repeat galectin family. On the basis of a phylogenetic analysis, we found that the mollusk sequences form a monophyletic group of tetradomain galectins unrelated to vertebrate galectins. HrGal showed specificity for galactosides and glucosides but only the sulfated sugars heparin and ι-carrageenan inhibited its hemagglutinating activity with a minimum inhibitory concentration of 4 mM and 6.25 X 10−5% respectively. The position of the sulfate groups seemed crucial for binding, both by carrageenans and heparin.

Simultaneous determination of six vitamin A substances by multi-wavelength HPLC and application to different marine shellfishes

An HPLC-DAD method was developed for the simultaneous analytical determination of six vitamin A substances (retinol, retinyl acetate, retinyl palmitate, retinoic acid, retinal and β-carotene) and applied to the analysis of vitamin A substances in five marine shellfishes. The chromatographic column was a YMC-β carotene C30 column (250 × 4.6 mm, 3 µm), and the mobile phases were selected as A (methanol), B (ultrapure water) and C (methyl tert-butyl ether). The initial ratio of the mobile phase was A:B:C= 90:1:9, which was maintained for 8 min, while the ratio of the three was changed to A:B:C= 35:0:65 and continued for 8 min, and finally returned to the initial ratio within 0.1 min. Ultrasound-assisted direct extraction was investigated, and the optimal extraction conditions were determined by exploring different sample-to-liquid ratios, extractants, extraction times and extraction temperatures. The method was validated and the established assay showed good linearity in the range of 0.5–50 μg/mL with good precision and accuracy. The experimental results showed that retinol, retinyl palmitate and β-carotene were present in the shellfish and there were seasonal variations of vitamin A substances in different marine economic shellfish.

Toxicity Testing Organisms for Marine Ecotoxicological Research in China

Since the late 1970s, marine ecotoxicology began to sprout and develop in China. Based on the principles of dose-response relationships, some marine organisms are used in toxicity tests to evaluate the impact of marine pollutants on marine organisms and marine ecosystems. At the early stage, marine ecotoxicological research mainly focused on the bioaccumulation, biomagnification, and biodegradation of traditional pollutants such as heavy metals, radioactive elements, organotin, petroleum hydrocarbons, and pesticides, as well as their toxic effects on survival, growth, and other physiological indicators. With the development of Chinese industry, marine pollution has become increasingly serious. In addition to the traditional marine pollutants, toxicological research has been conducted on emerging pollutants with potential risks to marine ecosystems, such as POPs, emerging organic pollutants, nanomaterials, and microplastics. Moreover, the species of marine organisms used in toxicity testing have become more diverse. The selection of testing organisms is essential for evaluating toxicity correctly. The toxicity tests should be conducted on a variety of organisms from different trophic levels to ensure the comprehensive understanding of the impact of pollutants on marine ecosystems. The major types of marine organisms used in the toxicity testing include marine alga, protozoa, rotifera, annelida, mollusc, echinoderma, arthropoda, cephalopoda, and marine fish, which have been used in the toxicological studies of various marine pollutants. The outcome results can serve as the scientific basis for the ecological risk assessment of marine pollutants and the establishment of seawater quality criteria. It should be noted that the sensitivity of different testing organisms to different types of pollutants is quite diverse. Therefore, in addition to conducting a battery of tests on a variety of species which play important roles in marine ecosystems, elucidating the toxic mechanisms in different species is also important for marine ecotoxicological studies. The application of the above-mentioned organisms in marine ecotoxicology research in recent years is briefly reviewed here. Particularly, the six commonly used marine model species (Skeletonema costatum, Euplotes vannus, oysters, sea urchins, Tigriopus japonicus, and Oryzias melastigma) used in toxicity testing are introduced in detail.