Microplastic (MP) pollution is widespread in aquatic environments, accumulating in organisms and transferring through the food web. This study investigated MP abundance, composition, and distribution in 15 fish species from eastern Guangdong, 11 of which are prey for Indo-Pacific humpback dolphins (Sousa chinensis). Results indicated the highest MP abundance in fish gastrointestinal tracts, with pelagic species being the most affected. Ethylene vinyl acetate (EVA) and polyethylene (PE), linked to local industrial activities, were the most prevalent polymers. Risk quotients (RQ) at 95th percentile for Indo-Pacific humpback dolphins exceeded one, suggesting significant MP exposure risk via prey ingestion. In contrast, the MPs risk for humans through fish consumption was minimal. These findings underscore the urgent need for improved plastic waste management to protect marine apex predators.

Benthic diatoms are the primary beach vegetation on sandy coasts, acting as the main primary producers in such environments. Changes in their community structure and biomass can have substantial impact on both the entire micro-food web and the nearshore shallow marine ecosystem. This study focused on four typical beaches along the southern coast of China (Fuzhou Changle Beach, Xiamen Huizhan Beach, Xiamen Guanyinshan Beach, and Beihai Silver Beach). Analysis of benthic diatoms and environmental factors revealed that the distribution of benthic diatom communities on the studied beaches is influenced by elevation, salinity changes due to freshwater inputs, sediment composition, and hydrodynamic factors. The most important factor is elevation, which reflects the location of the beach in the tidal zone. On Beihai Silver Beach and the Xiamen beaches, the mid-tidal and low tidal zones are more conducive to growth and reproduction of benthic diatoms, and some diatom species show preference for different tidal zones. On dissipative beaches, benthic diatom abundance peaks in the mid-tidal zone, whereas on low tidal terrace beaches, diatom abundance is generally low in the high tidal zone and relatively high in the low tidal zone. Additionally, low tidal terrace beaches exhibit a "steep increase zone" of diatom abundance at the junction of the steep and gentle slopes, indicating that benthic diatom abundance responds more to this type of beach landform than to that of dissipative beaches.

Marine organisms can serve as valuable bioindicators, providing insights into the spatial and temporal distribution of microplastics (MPs) in aquatic environments. While barnacles and mussels have shown promise as bioindicators of MP pollution in coastal environments, recent studies have questioned the efficacy of bivalves in this role. To address this, our research investigated the suitability of Mytilaster lineatus and Amphibalanus improvisus as biomonitors of MP pollution in the Caspian Sea through a comprehensive survey of these filter-feeding organisms. Sediment, seawater and organisms samples were collected from 9 stations during July to September 2022. MPs were detected in all compartments with an average of 0.57 ± 0.59 items/L for water, 72.66 ± 29.29 items/kg dry weight for sediment, 1.69 ± 0.79 items/individual or 7.96 ± 3.231 items/g wet weight (ww) for M. lineatus and 1.8 ± 0.9 items/individual or 35.18 ± 35.33 items/g ww for A. improvisus. MPs were prevailed by class 1000-3000 μm in size, black in color, fiber in shape and polyamide in polymer. The pollution load index (PLI) for seawater and sediment stations were 2.11 and 2.22, respectively, confirm low level risk of MP pollution at the sampling stations. There was a positive correlation between the MP abundance isolated from seawater and those extracted from the small species (p < 0.05). Bioconcentration factor (BCF) exhibited that both organisms absorbed and accumulated MPs from their surrounding water (BCF >1). A negative correlation was detected between the number of MPs extracted from organisms and their soft tissues (p < 0.01). Therefore, smaller individuals of M. lineatus and A. improvisus showed greater potential for biomonitoring. Our findings underscore the importance of species size in assessing MP pollution using biomonitors and recommend that future studies incorporate size-related variables for a more comprehensive understanding of MPs biomonitors.

Herein we study long-term changes in global sea surface temperature (SST) and chlorophyll-a concentration (CHL) in order to evaluate possible effects of climate change on the global marine ecosystems. Our approach is to analyze multi-model ensemble-means from global numerical-simulations available through the Coupled Model Intercomparison Project Phase 6 (CMIP6). A 250-year span consisting of the 1850-2014 historical period and the 2015-2099 climate-change projection was considered, where the Shared Socioeconomic Pathways (SSPs) 2.45 and 5.85 were selected as the projected climate-change scenarios. In the historical period, global linear trends show an SST increasing at 0.0024 °C year-1 and a CHL decreasing at -2.35x10-5 mg m-3 year-1, but by the last years (1985-2014) these changes become more abrupt: SST rising at 0.0146 °C year-1 and CHL declining at -1.49x10-4 mg m-3 year-1. During the intense climate-change scenario (SSP-5.85), SST increases at 0.0341 °C year-1 and CHL decreases at -0.0002 mg m-3 year-1, but in the last years (2070-2099) the warming is stronger (0.045 °C year-1) and the CHL decline is weaker (-0.0001 mg m-3 year-1). Additionally, Empirical Orthogonal Function (EOF) and dual Self-Organizing Maps (SOM) analyses on the model-data ensembles show: 1) significant correlations between SST and CHL patterns and climate teleconnection indices, 2) contracting polar and high latitude seascapes, 3) rising SST range (both high and low temperatures), 4) declining CHL in warming tropical seascapes, and 5) global expansion of low CHL levels. On the other hand, recent (2022-2023) global observed-SST anomalies mirror end-of-century projections, with extreme anomalies in tropical and subtropical regions and significant changes in near-polar regions. Thus, our findings emphasize the need to curb fossil fuel emissions in order to avoid irreparable consequences for the marine environment.

Cephalopods play a major role in marine food webs as both predators and prey. Although most of the Hg in cephalopods is present in the muscle, most studies on its accumulation by predators are based on concentrations in beaks. Here, using upper and lower beaks and buccal masses of Moroteuthopsis longimana, we evaluated the relationship between Hg concentrations in different cephalopod tissues. Hg concentrations in muscle tissue (329.9 ± 166.4 ng.g dw) were ≈100-fold higher than in different sections of the upper (3.5 ± 1.4 ng.g dw) and lower (3.5 ± 1.0 ng.g dw) beaks. A positive linear relationship was found between the Hg in the beak wing and in the muscle. Hg concentrations in the wing are therefore a useful proxy for the total Hg body burden, and their analysis provides a means of assessing the levels, transport and fate of Hg in marine ecosystems.

Tourism, urban development, and sargasso beaching caused environmental alterations in the Mexican Caribbean coasts. Little ecotoxicological information exists on the green turtle (Chelonia mydas) population inhabiting this region. Micronucleus (MN) and erythrocytic nuclear abnormalities (ENA) tests are non-destructive DNA damage biomarkers. We aimed to determine local (Punta Arenas, Akumal, Punta Herrero, and Xcalak) and annual (2015-2019) variability in MN/ENA frequency to understand genotoxic damage extent. Almost all the individuals sampled (n = 166) presented DNA damage (98.8%); the lack of correlations between MN/ENA and biological variables confirmed the usefulness of these tests as biomarkers. The southern foraging site had the highest number of MN/ENA; an increase over time was found in the most urbanized and the most protected sites, coinciding with previously reported regional variability of persistent organic compounds, heavy metals, and annual massive influx of sargasso. Considering the sentinel status of green turtles, the advantages of the blood tests, and the continuous accelerated urban development in the Caribbean, long-term monitoring of this species is advised.

The Sea Carp Cyprinus acutidorsalis (Wang) is an endemic species limited to a few estuaries in China, uniquely adapted to long-term residence in brackish water environments. This species is endangered due to anthropogenic disturbances, and its life history and habitat use remain poorly understood. This study is the first to investigate the life history and habitat utilization of Sea Carp in the Wanquan Estuary, Hainan Province, China, using otolith microchemistry. We analyzed the otolith samples from wild-captured Sea Carp and freshwater-reared juvenile fish. Significant differences in ratios of Li, Mg, and Sr between the two groups demonstrated that the otolith microchemistry can effectively reflect habitat conditions. We identified three distinct spawning areas, ranging from freshwater areas to nearshore habitats. Six life history contingents were identified, including four migratory and two resident types, with a preference for estuarine habitats. Our findings highlight the importance of multiple spawning grounds and diverse life histories in enhancing the adaptability and resilience of Sea Carp populations. We recommended that conservation efforts focus on maintaining habitat connectivity between estuarine and marine environments, protecting mangrove areas, and regulating fishing activities. This study provides valuable insights into the habitat utilization and life history of rare and endangered estuarine fish species, contributing to the development of effective management plans for their preservation worldwide.

Trade-offs play vital roles in evolutionary theory, linking organism performance to changing environments in the context of global change. Marine microalgae, as one of the most important groups of primary producers in the biosphere, exhibit significant trade-offs across multiple traits in response to environmental changes, such as elevated CO (and consequent ocean acidification) and warming. In this review, we synthesize recent findings on the trade-offs associated with both short-term phenotypic acclimation and long-term genotypic adaptation of marine microalgae. Specifically, we discuss distinct classes of trade-offs (i.e., allocation trade-offs, acquisition trade-offs and specialist-generalist trade-offs) between multiple traits, such as growth rate, photosynthesis, nutrient acquisition, and stress tolerance. We also explored the underlying mechanisms driving these trade-offs. Finally, we discuss the broader ecological consequences of these trade-offs, such as potential shifts in species composition and ecosystem functions, and outline key research directions to better predict marine ecosystem responses to future global change scenarios.

Coral reefs are suffering globally from the increased frequency and intensification of thermal anomalies, caused by anthropogenic climate change, leading to major mass bleaching events over the past three decades. Environmental factors, including temperature, geomorphology, interspecific competition, protection status and local settings, can modulate the severity of bleaching and the subsequent survival capacity of corals and hydrocorals after mass bleaching events. However, the complexity of environmental factors interacting over fine-scale spatial-temporal scales is still a major gap in understanding coral bleaching events of South Atlantic reefs. Here, we examined mortality and recovery patterns of the predominant hydrocoral species Millepora alcicornis after a mass bleaching event at the Northeastern coast of Brazil in 2019-2020. The ecological impact was evaluated by analyzing spatial factors, coral morphology, protection status and mortality rates in combination with the subsequent recovery potential influenced by overgrowth competition of dominant benthic organisms. The results indicate that hydrocorals located in proximity to the shore and shallow depths were more vulnerable with mortality rates of up to 90%, presumably related to higher light and temperature fluctuations. A total coral cover loss of approx. 50% was estimated for M. alcicornis within the study area and dead skeletons were overgrown by algal turfs and crustose coralline algae with the former being the predominant colonizer. In summary, our findings reveal fin-scale heterogeneous spatial vulnerability within the same coastal reef complex, indicating zones of high coral mortality. The described heterogeneous spatial vulnerability of the studied reef complex is an important factor to be considered in coral reef restauration and management plans to secure coral ecosystem services for the coming decades.

Global climate change has led to more frequent extreme temperature (extreme heat and cold) events, posing a serious threat to coral reef ecosystems. Higher latitudes are considered potential refuges for reef-building corals, but their response to extreme temperature stress in these regions remain unclear. This study, indoor simulated stress experiments ranging on Porites lutea from Weizhou Island in the northern part of the South China Sea, simulating suitable (26 °C) to extreme high (34 °C) and extreme low (12 °C) temperatures. Physiological, biochemical, and transcriptional responses, were analysed. Results showed P. lutea's tentacles contracted, and symbiotic relationships broke down at both high and low temperatures; leading to oxidative stress, and a higher risk of disease. The coral host's response to temperature stress was positively regulated, mainly through apoptosis and metabolic inhibition pathways, whereas Symbiodiniaceae C15 showed no significant response to either high- or low-temperature stress. The coral host played a dominant role in the holobiont's stress response, using similar mechanisms for both high- and low-temperatures with some differences in the details. This study enhances understanding the temperature response mechanisms of the dominant coral species, P. lutea in the relatively high-latitude regions of the South China Sea.

Seagrass beds serve crucial ecological functions, yet they are facing a severe decline necessitating immediate conservation and restoration efforts. Current assessments of seagrass habitat suitability are insufficient, thus hindering the restoration effects. This study used a combination of field surveys and satellite remote sensing to conduct a three-year monitoring of typical temperate seagrass beds in the Caofeidian and Xingcheng areas of the Bohai Sea. The relationships between seagrass community factors and environmental factors were investigated using Spearman correlation analysis, BIOENV analysis, and redundancy analysis (RDA). Subsequently, the weights of each environmental factor were determined using the Analytic Hierarchy Process (AHP), leading to the development of the Habitat Suitability Index (HSI). Seagrass habitat suitability maps for Caofeidian and Xingcheng areas were then generated using Geographic Information System (GIS). The results indicate that both seagrass ecosystems degraded during the study period, which coincided with a decreasing trend in habitat suitability shown by the suitability maps. This study provides a methodology for seagrass bed habitat suitability assessment, thereby contributing to the conservation and restoration of these vital ecosystems.

A better understanding of bacterial communities and the factors that drive them is essential to maintain their functions and services. As an ecosystem closely linked to human activities, the health of offshore aquaculture depends on the diversity and functions of bacteria in its environment. However, little attention has been paid to the vertical interface of the offshore aquaculture areas with shellfish net cages. In this study, high-throughput sequencing was used to analyze bacterial communities in different water layers of a net cage scallop farm in the offshore area of Northeast of China. Based on the results, an increased richness of bacterial communities was observed in the water adjacent to the net cages. Meanwhile, apparently different bacterial community compositions were observed among the water layers, with an enrichment of Cyanobacteria, Bacteroidota, and Firmicutes in the water layers above, parallel to, and below the net cages, respectively. According to the predicted functions, the bacterial communities of the water layers above, parallel to, and below the net cages were identified as phototrophy-, chemoheterotrophy-, and nitrogen respiration-dominated. Furthermore, network analysis revealed a complex but unstable bacterial community in the water layer containing the net cage. Finally, partial least squares path modelling revealed that the net cage aquaculture directly influenced the environmental variables and bacterial richness, which further induced the variations in bacterial community composition, and ultimately affected their ecological functions. These results provide a basic understanding of bacterial communities in net cage scallop farms and highlight the effects of offshore aquaculture on variations in ecological functions.

The coastal area of the Yellow Sea is a highly urbanized and industrialized region in China, which has been severely polluted because of intensive human activities. And the heavy metals (HMs) pollution has posed a serious threat to aquatic environments and ecosystem health. However, most studies have focused on the toxicity and bio-accumulation of HMs in zooplankton, while neglecting their effects on the overall community structure. To address the gap in this field, four research cruises was conducted in 2022 to analyze the concentrations of representative HMs (Hg, As, Cu, Zn, Pb, and Cd) in surface seawater along the Yellow Sea coast, as well as the composition and abundance of zooplankton communities, aiming to assess the potential ecological impacts in the region. The results indicated that the concentrations of the six HMs in the seawater were in the low to moderate range. Analytical results showed that Zn and As were key metals influencing the abundance and community composition of zooplankton along the Yellow Sea coast: an increase in Zn concentration, coupled with a decrease in As concentration, was associated with an increase in total zooplankton abundance and a more diverse community. The most frequently occurring zooplankton in the survey were copepods, which exhibited a higher tolerance to HMs. Additionally, the significant fluctuations of Zn, As, and Hg during spring and autumn led to explosive growth of Noctiluca scintillans. We observed that the influence of HMs on marine zooplankton was not isolated but rather interacts with multiple factors. Overall, this study highlights the possibility of alterations in marine ecological structures due to changes in HMs concentration levels. It underscores the importance of continuous monitoring of heavy metal concentrations in the Yellow Sea for the long-term protection of marine ecosystems.

By using Skeletonema dohrnii as the experimental algal species, we investigated how silicate concentration impacts the polyamine metabolism of diatoms in our experiment. Three different silicate concentrations were set for cultivation, and Skeletonema dohrnii at the exponential growth phase was selected to analyze basic physiological parameters, polyamine content, and Polyamine oxidase (PAO) gene expression under varying silicate concentrations. Results showed that low silicate concentrations led to reduced growth rate and polyamine content, with down-regulation of PAO gene expression. Conversely, high silicate concentrations did not significantly increase growth rate but did increase polyamine content and up-regulate the PAO gene. These findings suggested that changes in silicate concentration impact the growth rate and polyamine content of Skeletonema dohrnii, with the PAO gene potentially playing a role in regulating the algal response to silicate concentration variations. This study provides a foundation for further exploration of the PAO gene function in Skeletonema dohrnii.

Marine heatwaves (MHWs) have become more frequent and intense in the context of rapid climate change, causing detrimental effects on marine bivalves and ecosystems they sustain. While selective breeding programs for bivalves can substantially enhance growth performance, their ability to improve thermal stress tolerance remains largely unexplored. Here, we compared physiological energetics of wild and selectively bred Hongkong oysters (Guihao No. 1) under intensifying MHWs conditions. Following two consecutive events of MHWs, selectively bred oysters exhibited around 10% higher survival rate than that of wild oysters. Throughout the course of the experiment, the clearance rate of selectively bred oysters was significantly increased in comparison to wild oysters showing significantly depressed ability to feed. Nevertheless, exposure of selectively bred oysters to MHWs elicited significantly increased oxygen assumption and ammonia excretion rates, which in turn enhanced their O:N ratio. When couched into energetic terms, while MHWs inhibited the individual scope for growth, selectively bred oysters displayed better thermal tolerance than wild oysters. Taken together, our findings highlight the potential of new varieties of selectively bred oysters (such as Guihao No. 2) in coping with intensifying MHWs and guide the future development of selective breeding strategies to enhance the oyster thermal resilience in this era of unprecedented climate change.

Six sandy beaches located on the south coast of Viti-Levu, Fiji, were sampled to provide as a first aim, an environmental description based upon their physical and biological attributes, to serve as a reference tool for further monitoring programs. Beach face slopes were measured at 4 replicated transects stretching from the front dunes or the seaward reach of the tree vegetation (upper shore level) to the low tide level. Samples for analyses of sand particle size were collected at 4 tidal levels: the upper shore, the drift and effluent lines, and the low tide level. Samples for macroinvertebrates were sampled at the dry, retention, and resurgence/swash zones. Beach sites were categorized in terms of their morphodynamic types by means of photographs taken on site and expert analysis, taking into consideration beach width, beach face slopes and mean grain sizes of sands. Three of the studied beaches were labeled as reflective, two were intermediate and one was in between these two morphodynamic types. The mean number of intertidal species and abundance of macroinvertebrates (dominated by crustaceans and polychaetes) across all sites were 4.1 taxa (±1.7, ranges = 2-6) and 917 individuals per linear meter of beach (m) (±490, ranges = 133-1154). The second aim was to test the hypothesis that, along this coast, those biotic attributes are related to beach morphodynamic types. Our data allowed us to reject this hypothesis, since i) species richness and abundances of macroinvertebrates, did not differ significantly among beaches, ii) beach slope, beach width, and sediment grain size did not account for significant variations in the number of species and abundance of macroinvertebrates, and iii) multivariate analysis indicated that sediment grain size and beach slope just accounted for 31 % of the biotic richness variation. The third aim, was to evaluate the hypotheses that biotic richness in open ocean sandy beaches is not only affected by local environmental factors, but also by regional scale processes, such as ocean productivity. Thus, biotic information and coastal productivity data of ocean exposed sandy beaches along the tropical and subtropical belt at global scale were gathered from scientific literature. Based on upwelling and downwelling measurements, we conclude that oligotrophic ocean conditions, account for the low biodiversity and abundance of macroinvertebrate assemblages inhabiting the Fijian beaches studied. Our study establishes, for the first time, a reliable baseline for future studies and projects aimed at the protection of natural sandy beaches along the shores of the Fiji Islands and other isolated archipelagos of the tropical Pacific Ocean, where oligotrophic conditions prevail in their aquatic environment.

Global warming and heavy metals have become the major threat to the growth and reproduction of corals. However, unlike scleractinian corals, in the context of widespread coral degradation worldwide, there are few reports on the response of octocorallia corals to high-temperature stress and heavy metals. In the present study, we conducted indoor simulation experiments using Junceella squamata. We evaluated the physiological response of these corals under high-temperature stress at 33 °C and cadmium (Cd) stress by comparing the composition and diversity of their symbiotic bacteria and analyzing differences in their transcriptome. The results show that high-temperature stress has more severe adverse effects than cadmium stress. High-temperature stress disrupts coral symbiotic relationships, leading to an increase in alpha diversity associated with disease-causing bacteria, which may increase the risk of infection and potentially contribute to coral mortality. Meanwhile, cadmium stress increases the instability of the coral holobiont, potentially disrupting DNA stability and RNA transcriptional regulation. However, an increase in Cd-tolerant bacteria may help corals respond to cadmium stress. This study reveals the effects of harmful substances on coral and highlights the urgent need for action to protect octocorals in the face of environmental stress.

The increase of anthropogenic CO in the Earth's atmosphere reduces the pH and raises the temperature of the oceans. The combination of both factors impacts the physiological responses and calcium carbonate structures of marine organisms. This study assessed the performance of the juvenile stage of the gastropod Acanthina monodon, after it was continuously exposed to treatments at two pCO levels (400 and 1200 μatm) at two temperatures (10 °C and 15 °C) during the periods of embryonic encapsulated development and the early post-hatching juvenile stage. Juvenile performance was evaluated by quantifying shell growth, survival, foot adhesion strength, shell breakage resistance, and oxygen consumption rates. The results indicate that the combination of increased temperature and decreased pH increased juvenile shell growth, while only the decrease in pH had a negative effect on shell strength. However, juveniles were able to attach more strongly to substrates following exposure to the higher temperature level. Furthermore, the interaction of treatments had no effect on the metabolic rate or survival of juveniles, suggesting a possible compensatory effect of the juveniles to the more adverse conditions to which they were exposed.

Acanthus ebracteatus is an endangered true mangrove species with great ecological and medicinal values. Real-time quantitative PCR (RT-qPCR) has been widely used to investigate transcriptional responses in A. ebracteatus, which can facilitate its protection and medicinal usage. However, lack of prior knowledge on the optimal reference genes for RT-qPCR data normalization of A. ebracteatus, especially under stress scenarios, restricts gene expression investigations of this species. To address this issue, we evaluated the expression stability of seven candidate reference genes (ACT, PP2A, TUB, TUA, UBQ, EF-1α and RPS13) in leaves of A. ebracteatus upon heat, cadmium (Cd), drought, cold, flood and salt stress, respectively, using four state-of-the-art methods, GeNorm, NormFinder, BestKeeper and RefFinder. The results indicated that ACT was the most stably expressed in most scenarios, while EF-1α, PP2A and TUB ranked first under Cd, flood and salt stress, respectively. TUB was also the suboptimal reference gene for the samples exposed to drought and cold stress, and ACT was the second-best for Cd stress. For all the examined stress conditions, a combination of two reference genes was considered to be adequate enough for accurate expression standardization. A functional gene FLA17 was further employed to validate the performance of the candidate reference genes. The expression profiles of FLA17 displayed similar trends when using the top two stable reference genes, but were under- or overestimated when normalized by less stable genes, indicative of the importance of choosing the optimal reference genes for RT-qPCR normalization. Our findings provide a foundation for future gene expression studies of A. ebracteatus.

Diadromous fish species are characterised by spawning migrations between freshwater and marine environments, where they traverse through estuaries and close to coasts. This species group has declined substantially over the past decades due to anthropogenic effects such as habitat fragmentation and loss and overfishing. A rising potential threat to their population recovery is the increasing installation of subsea power cables (SPCs) which generate electromagnetic fields (EMF) as they transport energy from offshore wind farms to land. At least a part of the diadromous species are able to detect EMF, yet it is currently unknown whether EMF by SPCs affect their spawning migrations. With the increasing demand to offshore wind energy production and consequently the establishment of SPCs, the interaction between these SPCs and migrating diadromous fish species will rise in the near future. Consequently, there is an urgent need for knowledge on the impact of SPC-induced EMF on diadromous fish spawning migrations. Such knowledge can be obtained through a combination of lab and in situ experiments. International policy guidelines on the practicalities of deploying SPCs need to be established, taking into account the most up-to-date knowledge on the effect of SPC-induced EMF on diadromous fish spawning migrations.

Microplastics (MP) have spread to every corner of the globe, reaching remote areas like Antarctica. Recent studies detected MP in marine environments, including biota. Benthic organisms suffer negative effects upon MP ingestion, leading to impacts on their populations. To address the current knowledge gap on how Antarctic benthic invertebrates interact with MP, we conducted an experiment exposing a bivalve (Aequiyoldia eightsii) and two ascidians (Cnemidocarpa verrucosa and Molgula pedunculata) to polyethylene microbeads (mb). Specimens of each species were exposed for 48 h to two different concentrations of microbeads, a low dose (100 mb/l) and a high dose (1000 mb/l), with the same proportion of four different microbead size fractions (Fine (10-20 μm), Small (45-53 μm), Medium (106-125 μm), and Large (850-1000 μm)). After exposure, all three species had ingested microbeads. Significant differences between doses were observed in A. eightsii and C. verrucosa but not in M. pedunculata. Both ascidians ingested microbeads of all size fractions, whereas the bivalve did not ingest the largest microbeads. No significant differences were found between species in the number nor sizes of microbeads ingested. Minor variations between taxa may be attributed to the specific biology and anatomy of each species. Our study highlights the need for a deeper understanding of Antarctic benthic ecosystems, suggesting that the interaction with MP is species-specific. We believe that this study provides a baseline for assessing MP pollution in Antarctic benthic invertebrates and will help to inform policy-makers in protecting and preserving Antarctic marine ecosystems from MP pollution.