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Marine environments have increased in temperature by an average of 1°C since pre-industrial (1850) times [1]. Given that species ranges are closely allied to physiological thermal tolerances in marine organisms [2], it may therefore be expected that ocean warming would lead to abundance increases at poleward side of ranges and abundance declines toward the equator [3]. Here, we report a global analysis of abundance trends of 304 widely distributed marine species over the last century, across a range of taxonomic groups from phytoplankton to fish and marine mammals. Specifically, using a literature database, we investigate the extent that the direction and strength of long-term species abundance changes depend on the sampled location within the latitudinal range of species. Our results show that abundance increases have been most prominent where sampling has taken place at the poleward side of species ranges, and abundance declines have been most prominent where sampling has taken place at the equatorward side of species ranges. These data provide evidence of omnipresent large-scale changes in abundance of marine species consistent with warming over the last century and suggest that adaptation has not provided a buffer against the negative effects of warmer conditions at the equatorward extent of species ranges. On the basis of these results, we suggest that projected sea temperature increases of up to 1.5°C over pre-industrial levels by 2050 [4] will continue to drive latitudinal abundance shifts in marine species, including those of importance for coastal livelihoods., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Commercial overexploitation and climate change can alter the physiology and behavior of marine organisms, although intraspecific phenotypic responses to such changes can vary greatly depending on the environment, species, and severity of the stressor. Under the pace‐of‐life syndrome (POLS) hypothesis, behavior, physiology, and life‐history traits are linked, and thus, affected by selection targeting any aspect of organismal biology. However, these links are understudied in tropical marine fishes, and further work is needed to better understand the impacts of fisheries and climate change on wild stocks. Moreover, tropical regions have a greater reliance on fisheries; thus investigations should focus on species with substantial socioeconomic value to ensure benefits at the local level. This study aimed to address this need by measuring the behavior (boldness and activity), metabolism, and swimming performance (using a critical swim speed [Ucrit] test) of schoolmaster snapper Lutjanus apodus in Eleuthera, the Bahamas. We report a strong positive correlation between boldness and activity, high repeatability of these behavioral metrics, and two groupings that were consistent with “proactive” and “reactive” behavioral types. These behavioral types differed significantly in their swimming performance, with reactive individuals having a 13.1% higher mean Ucrit. In contrast, no significant differences were found in the measured metabolic parameters between behavioral types. This study is the first to investigate the intraspecific links between behavior and physiology in a snapper species, using the novel and ecologically relevant comparison of Ucrit with behavioral syndrome types. These data suggest that additional research is needed to better predict the success of proactive/reactive tropical fish if overexploited and as influenced by climate change. [ABSTRACT FROM AUTHOR]

Climate change is altering the distribution of marine organisms worldwide. This may, in turn, affect the overall structure and functioning of ecosystems, sometimes leading to low productive regimes. Pronounced shifts in distribution and migration have been observed for capelin (Mallotus villosus), one of the ecologically and commercially important species in the Arctic. This study attempts to discern whether a relationship existed between the altered capelin dynamics and the changing physical environmental conditions in the Iceland‐East Greenland‐Jan Mayen region. More specifically, three species distribution models were used to predict hindcasts (pre‐shift years 1993–2002) and nowcasts (post‐shift years 2003–2019) of capelin distribution based on relationships with temperature, salinity, current speed, net primary productivity, and bathymetry. The predicted probability of occurrence over these two time periods demonstrates that the changing environmental conditions have contributed to the modified distribution of the stock during its late feeding season in autumn and during the onset of spawning season in winter. The multi‐model approach used in this study has provided a solid statistical framework to describe the environmental niche of capelin and its potential responses to changing ocean climate. [ABSTRACT FROM AUTHOR]

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Species range shifts in response to warming and associated tropicalisation of coastal marine ecosystems are occurring globally, but the rates of change vary geographically and across ecosystems. Range shifts of biphasic habitat-forming species are critical as they can alter the physical and biological structure of habitats and thus change entire reef ecosystems. Microbial biofilms are key in regulating the dynamics of dominant habitat-forming species such as coral and kelps, and climate change is expected to impact this dynamic through two key pathways: (i) direct effects on biofilm composition, and (ii) impacts on the complex feedback loops between biofilms and habitat-forming organisms. Biofilms will therefore likely mediate range shifts of habitat-formers; thus, mechanistic understanding of their role is crucial to better predict ecosystem responses to environmental change. Marine species, such as corals and kelp, are responding to climate change by altering their distributions. Microbial biofilms underpin key processes that affect the establishment, maintenance, and function of these dominant habitat-formers. Climate-mediated changes to microbial biofilms can therefore strongly influence species' range shifts. Here, we review emerging research on the interactions between benthic biofilms and habitat-formers and identify two key areas of interaction where climate change can impact this dynamic: (i) via direct effects on biofilm composition, and (ii) via impacts on the complex feedback loops which exist between the biofilm microbes and habitat-forming organisms. We propose that these key interactions will be fundamental in driving the speed and extent of tropicalisation of coastal ecosystems under climate change. [ABSTRACT FROM AUTHOR]

Siliceous marine ecosystems play a critical role in shaping the Earth's climate system by influencing rates of organic carbon burial and marine authigenic clay formation (i.e., reverse weathering). The ecological demise of silicifying organisms associated with the Permian‐Triassic mass extinction is postulated to have elevated marine authigenic clay formation rates, resulting in a prolonged greenhouse climate during the Early Triassic. Yet, our understanding of the response of siliceous marine organisms during this critical interval is poor. Whilst radiolarians experienced the strongest diversity loss in their evolutionary history and perhaps also the greatest population decline of silica‐secreting organisms during this event, only a small number of Griesbachian (post‐extinction) localities that record siliceous organisms are known. Here, we report newly discovered latest Changhsingian to early Griesbachian (Clarkina meishanensis ‐ Hindeodus parvus Zone) radiolarians and siliceous sponge spicules from Svalbard. This fauna documents the survival of a low‐diversity radiolarian assemblage alongside stem‐group hexactinellid sponges making this the first described account of post‐extinction silica‐secreting organisms from the Permian/Triassic boundary in a shallow marine shelf environment and a mid‐northern paleolatitudinal setting. Our findings indicate that latitudinal diversity gradients for silica‐secreting organisms following the mass extinction were significantly altered, and that silica productivity was restricted to high latitude and deep water thermal refugia. This result has potential to further shape our understanding of changes in marine dissolved silica levels and in turn rates of reverse weathering, with implications for our understanding of carbon cycle dynamics during this interval. Key Points: First occurrence of siliceous sponges and radiolarians (biogenic silica) from a mid‐northern paleolatitude following the mass extinctionEvidence that extinction survivors show poleward range shifts in response to thermal stressBiosiliceous productivity persisted during the Early Triassic chert gap impeding the existence of Precambrian‐like marine conditions [ABSTRACT FROM AUTHOR]

Climatic changes have caused major environmental restructuring throughout the world's oceans. Marine organisms have responded to novel conditions through various biological systems, including genomic adaptation. Growing accessibility of next-generation DNA sequencing methods to study nonmodel species has recently allowed genomic changes underlying environmental adaptations to be investigated. This study used double-digest restriction-site associated DNA (ddRAD) sequence data to investigate the genomic basis of ecotype formation across currently recognized species and subspecies of bottlenose dolphins (genus Tursiops) in the Southern Hemisphere. Subspecies-level genomic divergence was confirmed between the offshore common bottlenose dolphin (T. truncatus truncatus) and the inshore Lahille's bottlenose dolphin (T. t. gephyreus) from the southwestern Atlantic Ocean (SWAO). Similarly, subspecies-level divergence is suggested between inshore (eastern Australia) Indo-Pacific bottlenose dolphin (T. aduncus) and the proposed Burrunan dolphin (T. australis) from southern Australia. Inshore bottlenose dolphin lineages generally had lower genomic diversity than offshore lineages, a pattern particularly evident for T. t. gephyreus , which showed exceptionally low diversity. Genomic regions associated with cardiovascular, musculoskeletal, and energy production systems appear to have undergone repeated adaptive evolution in inshore lineages across the Southern Hemisphere. We hypothesize that comparable selective pressures in the inshore environment drove similar adaptive responses in each lineage, supporting parallel evolution of inshore bottlenose dolphins. With climate change altering marine ecosystems worldwide, it is crucial to gain an understanding of the adaptive capacity of local species and populations. Our study provides insights into key adaptive pathways that may be important for the long-term survival of cetaceans and other organisms in a changing marine environment. [ABSTRACT FROM AUTHOR]

The IUCN Red List of Threatened Species is an authoritative tool in biodiversity conservation. Whilst IUCN criteria have been applied successfully to groups such as birds and mammals, a Red List assessment of British seaweeds in 2021 revealed that the categories to which seaweed species were assigned were dependent on how the criteria were applied. Here, this seaweed assessment is used as a case study with which to evaluate the IUCN methodology for use with 'non-standard' groups of organisms. A data-driven assessment of red (Rhodophyta), green (Chlorophyta) and brown (Phaeophyceae) seaweeds, which applied three (A, B and D) of the five IUCN criteria (A–E), categorized 13% of 617 British species as threatened. Following peer review, only 7% of species were categorized as threatened (1% Critically Endangered—CR, 3% Endangered—EN, 3% Vulnerable—VU), and 55% as Data Deficient. This reduction in species categorized as threatened suggests that strict application of the IUCN criteria may, at least for the seaweeds, over-estimate threat. As a result of this assessment, recommendations include the need for a more unified monitoring system and a review of the suitability for/application of the IUCN assessment criteria to some types of organisms. For example, in clonal populations, it is not possible to count individuals, and complex life histories cause additional complications. IUCN criteria must be applicable to a wide range of organisms, including seaweeds. [ABSTRACT FROM AUTHOR]

Long-chain polyunsaturated fatty acids (LC-PUFA) are nutritionally and pharmacologically well-recognized beneficial compounds widely used as nutrient supplements for various applications. As the human body cannot accomplish de novo synthesis of PUFA, we depend on exogenous bioresources for the supply of these essential PUFA for day-to-day activities. The PUFA global market is expected to reach about US$ 9.7 billion by 2032. The recent drop in natural fish catch and global climate change severely hamper the global PUFA supply chain. As a sustainable, promising resource, marine zoosporic microorganisms are considered to be safe and alternative primary producers of beneficial PUFAs for direct and indirect human consumption. However, by considering the limitations associated with strain efficiency, final product yield and production cost, more viable low-cost production strategies and establishment of highly efficient, stable, high production cell lines specific for marine zoosporic microbes are essential to meet global PUFA market demand. The exploration of the latest techniques for research and development could shape the dynamics better for the global market for marine zoosporic organism-based PUFA products. Therefore, this review first summarizes low-cost production and strain improvement strategies, and later highlights the advantages and commercial prospects for marine zoosporic microbe-derived PUFA. [ABSTRACT FROM AUTHOR]

Climate change is driving rapid and widespread erosion of the environmental conditions that formerly supported species persistence. Existing projections of climate change typically focus on forecasts of acute environmental anomalies and global extinction risks. The current projections also frequently consider all species within a broad taxonomic group together without differentiating species‐specific patterns. Consequently, we still know little about the explicit dimensions of climate risk (i.e., species‐specific vulnerability, exposure and hazard) that are vital for predicting future biodiversity responses (e.g., adaptation, migration) and developing management and conservation strategies. Here, we use reef corals as model organisms (n = 741 species) to project the extent of regional and global climate risks of marine organisms into the future. We characterise species‐specific vulnerability based on the global geographic range and historical environmental conditions (1900–1994) of each coral species within their ranges, and quantify the projected exposure to climate hazard beyond the historical conditions as climate risk. We show that many coral species will experience a complete loss of pre‐modern climate analogs at the regional scale and across their entire distributional ranges, and such exposure to hazardous conditions are predicted to pose substantial regional and global climate risks to reef corals. Although high‐latitude regions may provide climate refugia for some tropical corals until the mid‐21st century, they will not become a universal haven for all corals. Notably, high‐latitude specialists and species with small geographic ranges remain particularly vulnerable as they tend to possess limited capacities to avoid climate risks (e.g., via adaptive and migratory responses). Predicted climate risks are amplified substantially under the SSP5‐8.5 compared with the SSP1‐2.6 scenario, highlighting the need for stringent emission controls. Our projections of both regional and global climate risks offer unique opportunities to facilitate climate action at spatial scales relevant to conservation and management. [ABSTRACT FROM AUTHOR]

To investigate the spatiotemporal variations in the mixed layer depth (MLD) in the Arctic basins, a new criterion to determine the MLD, called the improved maximum angle method (IMAM), was developed. A total of 45 123 potential density profiles collected using Ice-Tethered Profilers (ITPs) in the Arctic basins during 2005–2021 were used to demonstrate the method's effectiveness. By comparing the results obtained by the fixed threshold method (FTM), percentage threshold method (PTM), and maximum gradient method (MGM) for profiles in the Canada Basin, Makarov Basin, and Eurasian Basin, we determined that the quality index (1.0 for perfect identification of the MLD) of the IMAM regarding the assessment of the MLD determination method reached 0.94, which is much greater than those of other criteria. Moreover, two types of the density profiles were identified based on the mixed layer development stage. The MLDs of the typical profiles determined using the IMAM were found to have better consistency with the original definition. By utilizing the new mixed layer criterion, the seasonal variations and regional differences in the MLD in the Arctic basins were analyzed. Spatially, the summer and winter MLDs in the Canada Basin were the shallowest (13.55 m in summer, 26.76 m in winter) than those in the Makarov (29.51 m in summer, 49.08 m in winter) and Eurasian (20.36 m in summer, 46.81 m in winter) basins due to the stable stratification in the upper ocean and the subsequent small effects of dynamic and thermodynamic processes (wind-driven stirring and brine rejection) in the Canada Basin. Seasonally, in the three Arctic basins, the average MLD was shallowest (22.77 m) in summer; it deepened through autumn and reached a winter maximum (41.12 m). [ABSTRACT FROM AUTHOR]

This chemical study reports a novel siderophore-like compound, β-cyclopiazonic acid (1, β-CPA) extracted from marine fungus Aspergillus flavus. The chemical structure of β-CPA was elucidated by a combination of extensive spectroscopic analyses and TDDFT-ECD calculations. The iron-binding ability and CAS assays demonstrate that β-CPA is a novel siderophore that features a different chemical structure from those of traditional siderophores. The β-CPA has no obvious influence on the growth of bacterium Pseudomonas aeruginosa PAO1. However, its iron chelator could promote the growth of P. aeruginosa PAO1, suggesting that P. aeruginosa employed siderophores to sequester iron, which is vital for their survival. The study provides the physiochemical evaluation of β-CPA, an unusual skeleton-structure siderophore, which for the first time, was proven to have the ability to bind iron and affect P. aeruginosa growth. This new discovery of siderophore provides an opportunity for developing novel anti-P. aeruginosa drugs. [ABSTRACT FROM AUTHOR]

Fishing logbook records the fishing behaviors and other information of fishing vessels. However, the accuracy of the recorded information is often difficult to guarantee due to the misreport and concealment. The fishing vessel monitoring system (VMS) can monitor and record the navigation information of fishing vessels in real time, and it may be used to improve the accuracy of identifying the state of fishing vessels. If the VMS data and fishing logbook are combined to establish their relationships, then the navigation characteristics and fishing behavior of fishing vessels can be more accurately identified. Therefore, first, a method for determining the state of VMS data points using fishing log data was proposed. Secondly, the relationship between VMS data and the different states of fishing vessels was further explored. Thirdly, the state of the fishing vessel was predicted using VMS data by building machine learning models. The speed, heading, longitude, latitude, and time as features from the VMS data were extracted by matching the VMS and logbook data of three single otter trawl vessels from September 2012 to January 2013, and four machine learning models were established, i.e., Random Forest (RF), Adaptive Boosting (AdaBoost), K-Nearest Neighbor (KNN), and Gradient Boosting Decision Tree (GBDT) to predict the behavior of fishing vessels. The prediction performances of the models were evaluated by using normalized confusion matrix and receiver operator characteristic curve. Results show that the importance rankings of spatial (longitude and latitude) and time features were higher than those of speed and heading. The prediction performances of the RF and AdaBoost models were higher than those of the KNN and GBDT models. RF model showed the highest prediction performance for fishing state. Meanwhile, AdaBoost model exhibited the highest prediction performance for non-fishing state. This study offered a technical basis for judging the navigation characteristics of fishing vessels, which improved the algorithm for judging the behavior of fishing vessels based on VMS data, enhanced the prediction accuracy, and upgraded the fishery management being more scientific and efficient. [ABSTRACT FROM AUTHOR]

Although accumulating data demonstrate that dietary supplementation of bamboo vinegar and charcoal powder (BVC) can significantly strengthen the immunity and boost the growth of domestic animals, its application potency still awaits verification in commercial fish species such as the large-scale loach Paramisgurnus dabryanus. The impacts of 90-day dietary supplementation of 1% and 2% BVC on survival and growth performance of the loach, and on the intestinal morphological characteristics and gut microflora were analyzed. Our data show that the large-scale loach supplied with BVC at the experimental doses had significant higher survival rates and better growth performance (indicated by greater weight gain (1.13–1.14 times), higher specific growth rate (1.04 times), and lower feed conversion ratio (0.88–0.89 times)) compared to that of the control (P<0.05). Histological examination revealed significant longer villus (3.22–5.54 times), deeper crypt (1.77–1.87 times), and thicker muscle (1.59–3.17 times) in the intestines of large-scale loach fed with BVC (P<0.05). Furthermore, we found that the gut microflora consisted of significantly fewer proportions of potential pathogenic bacterial species (Aeromonas veronii and Escherichia coli), but significantly greater proportions of beneficial microbes (Lactococus raffinolactis and Faecalibacterium prausnitzii). Therefore, dietary intake of BVC can promote intestinal tract development and optimize gut microflora, by which the survival and growth of large-scale loach may be improved. [ABSTRACT FROM AUTHOR]

Two new species belonging to genus Nassarius are described and illustrated based on shell morphology and radular features. Nassarius sanyaensis sp. nov., collected from intertidal zone of Sanya, Hainan Island, China, most resembles Nassarius lyraeformis (Marrat, 1880) in general shell shape, but differs from the latter in having remarkable nodules on shell surface. Nassarius beibuensis sp. nov., sampled from shallow water of Beibu Gulf, is most similar to Nassarius oblongus (Marrat, 1877), but can be distinguished from it mainly in having stronger sculpture. This study expands our knowledge of Nassarius diversity and distribution in China seas. [ABSTRACT FROM AUTHOR]

As "Bohai Red" scallops were originated from the hybrids between the Peruvian scallop (Argopecten purpuratus) and the bay scallop (Argopecten irradians) northern subspecies (Argopecten irradians irradians). Twelve Wnt members were identified from the two subspecies of bay scallop, and 13 Wnt genes were found in the genome of the Peruvian scallop. Protein structure analyses showed that most Wnt genes poses all 5 conserved motifs except Wnt1, Wnt2, Wnt6, and Wnt9 in the bay scallops and Wnt2 and Wnt9 in the Peruvian scallop. Unexpectedly, Wnt8 gene was present while Wnt3 was absent in both the bay scallops and the Peruvian scallop. Phylogenetic analysis revealed that Wnt3 might have disappeared in the early evolution of mollusks. The expression profile of Wnt genes in the "Bohai Red" exposed to different temperatures was examined by qRT-PCR. Results show that expression of Wnt genes responded differentially to temperature changes. The Wnt genes such as Wnt1, Wnt6, Wnt7, Wnt11, and WntA that responded slowly to low and high temperature stresses may be related to the maintenance of basic homeostasis. Other Wnt genes such as Wnt4, Wnt9, Wnt5, and Wnt2 that responded rapidly to low temperature may play an important role in organismal protection against low temperature stress. And yet some Wnt genes including Wnt10, Wnt16, and Wnt8 that responded quickly to high temperature stress may play key roles in response to high temperature stress. The results provide new insights into the evolution and function of Wnt genes in bivalves and eventually benefit culture of "Bohai Red" scallops. [ABSTRACT FROM AUTHOR]

Geochemical behaviors of heavy metals are closely related to their chemical state that can be divided by sequential extraction into exchangeable (F1), bound to carbonates (F2), bound to Fe-Mn oxides (F3), bound to organic matter or sulfide (F4), and residual (F5). Uranium in sediment of the Huanghe (Yellow) River, China, in different chemical states was extracted using the five-step procedure of Tessier and the source and sink were analyzed. Results show that more than 70% of the total uranium was immobile residual F5 in abundance, followed in order of F4>F3>F2>F1, indicating that the main source of uranium in the sediments was from weathered rock in the drainage basin. In addition, the uranium in the sediments presents potential exogenous input in the Lanzhou, Baotou, and Tongguan reach. Fe-Mn oxides are main carriers of unstable uranium, especially those of F1 and F3. Calcite and illite are secondary adsorption minerals of unstable uranium in sediments under natural conditions. Human activities can also produce an obvious impact on uranium speciation. This study provides a reference for the application of sequential extraction in analyzing the source and sink of uranium in river sediments. [ABSTRACT FROM AUTHOR]

In recirculating aquaculture systems (RASs), the effective treatment of aquaculture tailwater is essential to maintain the health of the RAS. This study investigated the optimal time and method for tailwater treatment during three periods of the aquaculture of the Litopenaeus vannamei: nursery (0–26 d), middle (27–57 d), and later (57–104 d). The variation of several water parameters during the dissolution of total suspended solid (TSS) in tailwater, applied with the effects of ozone on the microorganism and water quality parameters were investigated. Results showed that the TSS concentrations in tailwater decreased with time, although not significantly (P>0.05), whereas total ammonia nitrogen (TAN), nitrite (NO2−-N), and nitrate (NO3−-N) increased significantly (P<0.05). Therefore, TSS should be removed from the tailwater as early as possible, being most optimal within 4 h. Ozone removed 38.24%–48.95% of TSS, 17.78%–90.14% of TAN, and 87.50%–98.90% of NO2−-N after 4 h of treatment. However, it resulted in the significant accumulation of NO3−-N. Moreover, the total number of Vibrio and bacterial counts in aquaculture tailwater was reduced completely by ozone within 4 h. Thus, these results provided technical details and data support for the effective treatment of tailwater from shrimp RAS. [ABSTRACT FROM AUTHOR]

Dam construction has a critical effect on river ecosystems in the world, resulting in a rapid decline in biodiversity and ecosystem health. However, the effect of dam construction on the assemblage pattern of benthic diatoms remains unclear. The benthic diatoms assemblages in the tributary backwater area of the Three Gorges Reservoir (TGR) were investigated under low water level (LWL) and high water level (HWL) conditions. Results show that Discostella stelligera, Nitzschia palea, and Craticula subminuscula were dominant species in LWL, while Achnanthidium minutissimum and Nitzschia dissipata were dominant in HWL. Furthermore, environmental variables, productivity parameters, diversity indices, and community similarity were found significantly different between LWL and HWL periods. The Mantel test indicated that both environmental and spatial factors had significant effects on diatom communities in backwater area, while productivity was also a key driving force in LWL. The variation partitioning analysis (VPA) further demonstrated that environment factors could explain the largest variance of diatom assemblages in HWL (9%) and LWL (11%), followed by spatial factors. The relative importance of productivity to diatom community was significantly enhanced in LWL, but only a slight effect was found in HWL. These results indicate that the diatom assemblages were shaped by both environmental filtering and spatial factors. The relative importance of spatial factors depended on the degree of productivity. Therefore, the homogenization of diatom communities due to environmental disturbance, e.g. eutrophication and dam building, is the underlying mechanism in assembling the benthic diatoms. [ABSTRACT FROM AUTHOR]

Three polyamines (PAs) (spermidine (Spd), spermine (Spm), and putrescine (Put)) were used as growth regulators to the marine macroalgae Gracilariopsis lemaneiformis and to female gametophyte and reproductive tissues (cystocarps were constructed), which led to early maturation of cystocarps and spore release. Laboratory cultivation revealed that exogenous PA application accelerated the development of cystocarps, and the mean sporeling growth rate was 20%–50%/d during the initial week of cultivation. The spore count (SC), survival rate (SR), and germination rate (GR) of G. lemaneiformis showed different responses to PA (10−6 mol/L and 10−3 mol/L) treatments under different temperatures (18, 26, and 34 °C), light intensities (30, 60, and 90 µmol photons/(m2·s)), salinities (25, 30, and 35), and nutrient levels (25: 2.5, 50:5.0, and 75:7.5 µmol/L NH4Cl:K2HPO4), and the optimal conditions were 26 °C, light intensity of 60 µmol/(m2·s), salinity of 35, and nutrient level of 50: 5.0 µmol/L NH4Cl: K2HPO4. Under the optimum conditions, the SC per cystocarp increased by 82.38%, and the spore SR and GR increased by 33.07% and 46.44%, respectively. Each experiment lasted for 7 days, with the highest SC on Day 4 and plateauing on Day 7. The results indicate that PAs could promote the early maturation, spore release, survival, and germination of G. lemaneiformis under laboratory conditions. [ABSTRACT FROM AUTHOR]

Submarine canyon-channel systems have been documented in the Parece Vela Basin, West Mariana Ridge; however, the mechanism of the formation and controlling factors remain poorly understood. Based on high-resolution multibeam bathymetric data and two-dimensional (2D) seismic profiles, we identified and mapped the submarine canyon-channel system along the middle segment of West Mariana Ridge in the Philippine Sea. These submarine canyon-channels show a main W-E orientation at depth of 2 000–4 500 m. They are approximately 72–128 km in length and 1.3–15 km in width, and their canyon heads are adjacent to the seamounts with several branches. The upper reaches of submarine canyon-channels are characterized by deeply incised, narrow, V-shaped thalwegs, suggesting the powerful erosion of gravity flows. The distinguished sediment waves are suggested to be resulted from the interaction of turbidity currents and seafloor. Our observations demonstrate that gravity flows originated from the collapses of seamount flanks plays a vital role in developing the submarine canyon-channel system along the West Mariana Ridge. This work provides better understanding of erosion, transport, and deposition of sediments from subducting ridges to deep-water basins, and also new insights into the origin and evolution of submarine canyon-channel systems along subducting ridges. [ABSTRACT FROM AUTHOR]

Zooplankton are important linkages in the food web and can respond nonlinearly to environmental changes. Marine organisms thrive from spring to summer. Thus, it is crucial to understand how ecological functions of zooplankton communities may shift under seasonal environmental changes during this period. Samples were collected from May to August (May, June-I, June-II, July-I, July-II, and August) in 2018 in Haizhou Bay, Jiangsu, East China for zooplankton and environmental variables. Crustaceans accounted for 75 out of 134 zooplankton taxa and 91.8% of total zooplankton abundance. The average abundance of crustacean varied between 2 824.6±635.4 inds./m3 in July-II and 6 502.7±1 008.8 inds./m3 in June-II. Multivariate analyses results showed that the dissimilarity of community increased gradually in the time series. Body length, feeding type, trophic group, and reproduction mode were used to investigate crustacean community functions. Trait-based functional groups contained species with similar ecological roles. Functional diversity fused the differences of species and trait. The proportion of large-sized species (2–5 mm) decreased with the increasing proportion of medium-sized species (1–2 mm). The proportion of current feeders increased with the drop in the proportion of mixed feeders. Parthenogenesis species increased with decreasing free spawners, and omnivores-carnivores increased with decreasing omnivoresherbivores. Generalized additive models suggested that temperature was the main driver of variations in crustacean zooplankton function. Seven identified functional groups varied with increasing temperature. Omnivorous-herbivorous copepods declined (90.0%–68.0%), whereas the parthenogenetic cladocerans increased (0–24.1%). The small egg-brooding ambush copepods fluctuated (6.5%–9.3%) with increasing water temperature. The other functional groups changed slightly. Functional diversity also varied according to temperature changes. The community structure and ecological function of crustacean zooplankton community showed gradual changes with increasing temperature from spring to summer. [ABSTRACT FROM AUTHOR]

Ocean acidification (OA) has provoked changes in the carbonate saturation state that may alter the formation and structural biomineralisation of calcium carbonate exoskeletons for marine organisms. Biomineral production in organisms such as cold-water corals (CWC) rely on available carbonate in the water column and the ability of the organism to sequester ions from seawater or nutrients for the formation and growth of a skeletal structure. As an important habitat structuring species, it is essential to examine the impact that anthropogenic stressors (i.e., OA and rising seawater temperatures) have on living corals and the structural properties of dead coral skeletons; these are important contributors to the entire reef structure and the stability of CWC mounds. In this study, dead coral skeletons in seawater were exposed to various levels of pCO2 and different temperatures over a 12-month period. Nanoindentation was subsequently conducted to assess the structural properties of coral samples' elasticity (E) and hardness (H), whereas the amount of dissolution was assessed through scanning electron microscopy. Overall, CWC samples exposed to elevated pCO2 and temperature show changes in properties which leave them more susceptible to breakage and may in turn negatively impact the formation and stability of CWC mound development. [ABSTRACT FROM AUTHOR]

The trophic relationships interconnecting marine organisms together into a dynamic trophic network drive the structure and the functioning of the entire ecosystem. Since the flow of carbon within trophic networks is controlled by a variety of functional traits related to food acquisition and individual survival, it is crucial to understand how functional diversity relates to marine ecosystems properties such as the resistance and resilience against perturbations.In the Arctic, marine ecosystems are facing stronger and faster environmental changes than anywhere on Earth, leading to profound perturbations in the planktonic assemblages at the base of the trophic networks. While it is known that mesozooplankton plays a crucial role of matter and energy hub within marine Arctic food web, the precise role of the diverse mesozooplankton functional groups in carbon circulation and in marine ecosystems functioning remains poorly known.We coupled a trait‐based approach of mesozooplankton diversity to an ecological network analysis approach to test whether similar mesozooplankton functional groups played similar ecological roles in three Arctic ecosystems during the summer period. We formed nine mesozooplankton functional groups by gathering different species according to their feeding strategies. Then we implemented those into inverse food web models (linear inverse modelling) describing three contrasted Arctic ecosystems. In each ecosystem, we performed sensitivity analysis experiments where each mesozooplankton functional group was removed one at a time.Our results showed that, although the same main functional groups composed the three ecosystems, the few outstanding changes observed in the carbon circulation within the food web were strongly controlled by both the initial whole‐network properties and productivity of the ecosystem.The various roles played by a given mesozooplankton functional group in the ecosystem depend on its impact on carbon flows through the food web it belongs to. As a result, identifying which functional groups could be threatened, and which carbon flows could be altered by climate change is critical information to predict future ecosystems functioning. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Ocean warming has been affecting marine ecosystems over the past few decades. The signature of ocean warming in global fisheries catch data has been identified through a variety of methods, one of which is the mean temperature of the catch (MTC) index. The MTC is derived from the average temperature preference of fished species weighted by their contribution to annual catches. Here, we used MTC to explore the fisheries catch responses to warming, from 1950 to 2016, along a latitudinal gradient in the western Pacific Ocean, from 37° N, via 2.5° S in the central western Pacific, to 36° S. The tropicalization of catches in a given geographic space, i.e., the increased catch of species with affinity to warmer waters, as a result of increasing sea temperature and the associated poleward migration of species, rather than any large-scale oceanographic variability, was apparent through the increasing MTC at higher latitudes. In particular, MTC in temperate Japan increased by 0.33 °C per decade over the time series. The MTC in subtropical/temperate southeast Australia increased by 0.24 °C per decade over the full time period and by 1.24 °C per decade after 2002. The observed MTC increase was caused by the increasing dominance of thermophilous (preferring warmer waters) over psychrophilous (preferring cooler waters) taxa in the catches in these waters. On the other hand, the MTC in tropical Indonesian waters, as well as the ratio of thermophilous to psychrophilous taxa, showed a gentle yet consistent decrease of 0.05 °C per decade over the full time period. This finding supports the tropicalization hypothesis, given the limited scope for further tropicalization of catches in the already tropical ecosystem of Indonesia. Ocean warming has indeed been altering the distribution of marine organisms, particularly in temperate ecosystems as thermophilous taxa become more abundant, while psychrophilous taxa abundance decreases. Tropicalization impacts fisheries and catch composition and is, therefore, expected to cause conflicts among fishers and challenge fisheries management. [ABSTRACT FROM AUTHOR]

Global warming is associated with an increase in sea surface temperature and its variability. The consequences of evolving in variable, fluctuating environments are explored by a large body of theory: when populations evolve in fluctuating environments the frequency of fluctuations determines the shapes of tolerance curves (indicative of habitats that organisms can inhabit) and trait reaction norms (the phenotypes that organisms display across these environments). Despite this well-established theoretical backbone, predicting how trait and tolerance curves will evolve in organisms at the foundation of marine ecosystems remains a challenge. Here, we used a globally distributed phytoplankton, Thalassiosira pseudonana, and show that fluctuations in temperature on scales of 3–4 generations rapidly selected for populations with enhanced trait plasticity and elevated thermal tolerance. Fluctuations spanning 30–40 generations selected for the formation of two stable, genetically and physiologically distinct populations, one evolving high trait plasticity and enhanced thermal tolerance, and the other, akin to samples evolved under constant warming, with lower trait plasticity and a smaller increase in thermal tolerance. [ABSTRACT FROM AUTHOR]

Since the impacts of climate change on marine benthic organisms are already detectable in many aspects, it is crucial to address the potential responses of marine organisms and their interactions with the environment. In particular, the study of phenotype traits along latitudinal gradients is a powerful tool for exploring species responses in a changing environment. This work aims to: i) Quantify the variation in shell shape and size of the stripped clam Ameghinomya antiqua (King, 1832) along a 1600 km latitudinal gradient in the Atlantic Patagonian coast using geometric morphometric (GM) methods; ii) Identify environmental effects on shell shape and size change, using generalized additive mixed models GAMMs; iii) Estimate the effect size of different factors influencing shell shape and size variation. The combination of GM and GAMM allowed the quantification and identification of previously unknown relationship between morphological axes of variation and environmental variables. Results suggest that salinity is the most important factor determining shell shape, mainly affecting the outline while temperature has a substantial but weaker effect. More elongated shells and longer ligaments are observed under (less favorable) conditions of low salinity and temperature. GAMM showed that chlorophyll- a concentration, used as a proxy for food supply, has the most significant effect on shell size, and shell growth does not match the somatic soft-tissue growth. These results may help to predict the effects of climate change on the size and shape of marine benthic species and bivalves in particular. Furthermore, they provide new insights for using shell size and shape as proxies for the reconstruction of past environments and climates. [ABSTRACT FROM AUTHOR]

Increasing levels of greenhouse gases lead to ocean warming, which affects a range of marine organisms. Corals live in a narrow temperature range and become stressed when the temperatures change. Bleaching occurs when the temperature exceeds the coral's threshold, and can be severe when this is combined with other stressors such as light. In order to understand how temperature and light affect corals in their physiological responses and photosynthetic performance, Pocillopora acuta from Maiton Island (MT) and Panwa Cape (PW), representing different environments, were investigated. The results show that light and temperature had by regime different effects on Symbiodiniaceae photosynthesis and the coral growth rate. There was a synergistic effect of elevated temperature and light on photosynthesis, as observed in the photochemical efficiency and pigment contents, suggesting photo-damage. A higher growth rate in Panwa corals was observed in control, and while elevated temperature reduced coral growth. Elevated temperature affected the Panwa coral less, suggesting that corals from this regime might be able to recover when the temperature returns to normal. This information is important for predicting the coral responses to elevated temperature especially in the summer, as regards the possibility of coral bleaching. [ABSTRACT FROM AUTHOR]

Unusual records of marine organisms beyond their known distribution range aid the identification of dispersal capabilities, health issues, changing oceanographic patterns and/or anomalies, and may drive attention to underlying shifts in the polar marine environment. Here we report on an adult male sub-Antarctic fur seal, Arctocephalus tropicalis, sighted at Saint Peter and Saint Paul archipelago, also known as Arquipélago de São Pedro e São Paulo (ASPSP) (00° 56′ N; 29° 22′ W), Brazil, on January 18–21, 2022. The animal appeared healthy and stayed in the rocky islands of the archipelago making frequent incursions to sea. We have compiled information from wandering individuals A. tropicalis and found that this is the first indisputable record for the species in the ASPSP, crossing the ecuador to the Northern Hemisphere. We suggest that it comes from Gough or Tristan da Cunha islands which are the closest breeding locations of this species. Therefore, this male traveled at least ~ 5500 km from the natal area and was 1931 km north from the second northernmost sighting of this species in Ascension Island. We speculate that this species may be using currents and/or shallower mid-ocean ridges to guide dispersal routes from subpolar regions to the North. [ABSTRACT FROM AUTHOR]

Despite the great interest in the consequences of global change stressors on marine organisms, their interactive effects on cadmium (Cd) bioaccumulation/biotoxicity are very poorly explored, particularly in combination with the toxicokinetic model and molecular mechanism. According to the projections for 2100, this study investigated the impact of elevated p CO 2 and increased temperature (isolated or joint) on Cd uptake dynamics and transcriptomic response in the marine copepod Tigriopus japonicus. Toxicokinetic results showed significantly higher Cd uptake in copepods under increased temperature and its combination with elevated p CO 2 relative to the ambient condition, linking to enhanced Cd bioaccumulation. Transcriptome analysis revealed that, under increased temperature and its combination with elevated p CO 2 , up-regulated expression of Cd uptake-related genes but down-regulation of Cd exclusion-related genes might cause increased cellular Cd level, which not only activated detoxification and stress response but also induced oxidative stress and concomitant apoptosis, demonstrating aggravated Cd biotoxicity. However, these were less pronouncedly affected by elevated p CO 2 exposure. Therefore, temperature seems to be a primary factor in increasing Cd accumulation and its toxicity in the future ocean. Our findings suggest that we should refocus the interactive effects between climate change stressors and Cd pollution, especially considering temperature as a dominant driver. [Display omitted] • Elevated temperature increased Cd uptake in Cd-treated Tigriopus japonicus. • Elevated temperature caused more serious oxidative stress and apoptosis. • Increased p CO 2 showed a less pronounced effect on Cd uptake and its toxicity. • Temperature plays a dominant role to enhance Cd uptake and its molecular toxicity. • Accurate Cd toxicity assessment should consider elevated temperature condition. [ABSTRACT FROM AUTHOR]

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. Here, we investigate how the symbiotic relationship between endolithic microbes and the blue intertidal mussel Mytilus edulis mitigates thermal stress during the unprecedented 2022 atmospheric heatwave in the English Channel. Microbial infestation of the shell significantly enhanced mussel survival, particularly higher on the shore where thermal stress was greater. Using data from biomimetic temperature loggers, we predicted the expected thermal buffer and observed differences up to 3.2 °C between individuals with and without symbionts under the known conditions of the heat wave-induced mortality event. The ecological implications extend beyond individual mussels, affecting the reef-building capacity of mussels, with potential cascading effects for local biodiversity, carbon sequestration, and coastal defence. These findings emphasize the importance of understanding small-scale biotic interactions during extreme climate events and provide insights into the dynamic nature of the endolith-mussel symbiosis along a parasitic-mutualistic continuum influenced by abiotic factors. • Heatwaves are intensifying, posing significant threats to ecosystems and well-being. • Intertidal communities, facing high thermal variability, are particularly vulnerable. • Endolithic microbes induce shell changes, enhancing mussel survival. • These symbionts increased survival during the 2022 English Channel heatwave. • The impact extends beyond the single mussel species to the intertidal biodiversity it supports. [ABSTRACT FROM AUTHOR]

An ongoing loss of experts in marine cellular biochemistry and physiology (CBP) is stagnating the generation of knowledge upon which rapidly growing "omics" approaches rely, ultimately hampering our ability to predict organismal responses to climate change. The ongoing loss of expertise on the biochemistry and physiology of marine organisms is hampering our understanding of biological mechanisms and will ultimately affect our ability to predict organismal responses to climate change. [ABSTRACT FROM AUTHOR]

With the over 2000 marine fungi and fungal-like organisms documented so far, some have adapted fully to life in the sea, while some have the ability to tolerate environmental conditions in the marine milieu. These organisms have evolved various mechanisms for growth in the marine environment, especially against salinity gradients. This review highlights the response of marine fungi, fungal-like organisms and terrestrial fungi (for comparison) towards salinity variations in terms of their growth, spore germination, sporulation, physiology, and genetic adaptability. Marine, freshwater and terrestrial fungi and fungal-like organisms vary greatly in their response to salinity. Generally, terrestrial and freshwater fungi grow, germinate and sporulate better at lower salinities, while marine fungi do so over a wide range of salinities. Zoosporic fungal-like organisms are more sensitive to salinity than true fungi, especially Ascomycota and Basidiomycota. Labyrinthulomycota and marine Oomycota are more salinity tolerant than saprolegniaceous organisms in terms of growth and reproduction. Wide adaptability to saline conditions in marine or marine-related habitats requires mechanisms for maintaining accumulation of ions in the vacuoles, the exclusion of high levels of sodium chloride, the maintenance of turgor in the mycelium, optimal growth at alkaline pH, a broad temperature growth range from polar to tropical waters, and growth at depths and often under anoxic conditions, and these properties may allow marine fungi to positively respond to the challenges that climate change will bring. Other related topics will also be discussed in this article, such as the effect of salinity on secondary metabolite production by marine fungi, their evolution in the sea, and marine endophytes. [ABSTRACT FROM AUTHOR]

Under climate change, marine organisms will need to tolerate or adapt to increasing temperatures to persist. The ability of populations to cope with thermal stress may be influenced by conditions experienced by parents, by both genetic changes and transgenerational phenotypic plasticity through epigenetics or maternal provisioning. In organisms with complex life cycles, larval stages are particularly vulnerable to stress. Positive parental carry‐over effects occur if more stressful parental environments yield more tolerant offspring while the opposite pattern leads to negative carry‐over effects. This study evaluated the role of parental effects in determining larval thermal tolerances for the intertidal mussel, Mytilus californianus. We tested whether thermal environments across a natural gradient (shoreline elevation) impacted mussel temperature tolerances. Lethal thermal limits were compared for field‐collected adults and their larvae. We observed parental effects across one generation, in which adult mussels exposed to warmer habitats yielded less tolerant offspring. Interestingly, although parental environments influenced offspring tolerances, we found no clear effects of habitat conditions on adult phenotypes (tolerances). We found indicators of trade‐offs in energy investment, with higher reproductive condition and larger egg diameters in low stress environments. These results suggest that parental effects are negative, leading to possible adverse effects of thermal stress on the next generation. [ABSTRACT FROM AUTHOR]

Worldwide, rising ocean temperatures are causing declines and range shifts in marine species. The direct effects of climate change on the biology of marine organisms are often well documented; yet, knowledge on the indirect effects, particularly through trophic interactions, is largely lacking. We provide evidence of ocean warming decoupling critical trophic interactions supporting a commercially important mollusc in a climate change hotspot. Dietary assessments of the Australian blacklip abalone (Haliotis rubra) indicate primary dependency on a widespread macroalgal species (Phyllospora comosa) which we show to be in state of decline due to ocean warming, resulting in abalone biomass reductions. Niche models suggest further declines in P. comosa over the coming decades and ongoing risks to H. rubra. This study highlights the importance of studies from climate change hotspots and understanding the interplay between climate and trophic interactions when determining the likely response of marine species to environmental changes. [ABSTRACT FROM AUTHOR]

Coral reefs globally are increasingly impacted by climate change. High temperature and pCO2 levels disrupt multiple physiological and biochemical pathways in marine organisms, often leading to disease and mortality in sensitive reef species. Host-associated microbes contribute critical functions that underpin host health, and environmentally induced changes in microbial communities represent a potential source for new metabolic features within holobiont systems. However, whether the acquisition of new beneficial microbial functions contributes to environmental acclimatisation of reef species is currently unknown. Using extensively studied model systems, we identify potential direct and indirect microbiome-mediated mechanisms that may contribute to environmental acclimatisation in reef invertebrate species. These mechanisms include increasing energy metabolism in the host, reduction of oxidative stress, regulation of nutrients in host cells, and increased pathogen resistance. We also propose a robust experimental strategy to test how microbial metabolic pathways may facilitate environmental acclimatisation of reef taxa. Understanding the mechanisms of microbiome-mediated acclimatisation and the timescales over which it can occur will be critical for predicting reef ecosystem dynamics under future climate scenarios and applying effective reef conservation strategies. [ABSTRACT FROM AUTHOR]

Aim: Temperature is fundamental to the physiological and ecological performance of marine organisms, but its role in modulating the magnitude of ecological impacts by exotic species remains unresolved. Here, we examine the relationship between thermal regimes in the range of origin of marine exotic species and sites of measured impact, after human‐induced introduction. We compare this relationship with the magnitude of impact exerted by exotic species on native ecosystems. Location: Global. Time period: 1977–2017 (meta‐analysis). Major taxa studied: Marine exotic species. Methods: Quantitative impacts of exotic species in marine ecosystems were obtained from a global database. The native range of origin of exotic species was used to estimate the realized thermal niche for each species and compared with the latitude and climatic conditions in recipient sites of recorded impact of exotic species. The difference in median temperatures between recipient sites and the thermal range of origin (i.e., thermal midpoint anomaly) was compared with the magnitude of effect sizes by exotic species on native species, communities and ecosystems. Results: Recorded impacts occurred predominantly within the thermal niche of origin of exotic species, albeit with a tendency toward higher latitudes and slightly cooler conditions. The severity of impacts by exotic species on abundance of native taxa displayed a hump‐shaped relationship with temperature. Peak impacts were recorded in recipient sites that were 2.2°C cooler than the thermal midpoint of the range of origin of exotic species, and impacts decreased in magnitude toward higher and lower thermal anomalies. Main conclusions: Our findings highlight how temperature and climatic context influence ecological impacts by exotic species in marine ecosystems and the implications for existing and novel species interactions under climate change. [ABSTRACT FROM AUTHOR]

Marine heatwaves (MHWs)—periods of extremely high ocean temperatures in specific regions—have occurred in all of Earth’s ocean basins over the past two decades, with severe negative impacts on marine organisms and ecosystems. However, for most individual MHWs, it is unclear to what extent they have been altered by human-induced climate change. We show that the occurrence probabilities of the duration, intensity, and cumulative intensity of most documented, large, and impactful MHWs have increased more than 20-fold as a result of anthropogenic climate change. MHWs that occurred only once every hundreds to thousands of years in the preindustrial climate are projected to become decadal to centennial events under 1.5°C warming conditions and annual to decadal events under 3°C warming conditions. Thus, ambitious climate targets are indispensable to reduce the risks of substantial MHW impacts. [ABSTRACT FROM AUTHOR]

Concurrent anthropogenic global climate change and ocean acidification are expected to have a negative impact on calcifying marine organisms. While knowledge of biological responses of organisms to oceanic stress has emerged from single‐species experiments, these do not capture ecologically relevant scenarios where the potential for multi‐organism physiological interactions is assessed. Marine algae provide an interesting case study, as their photosynthetic activity elevates pH in the surrounding microenvironment, potentially buffering more acidic conditions for associated epiphytes. We present findings that indicate increased tolerance of an important epiphytic foraminifera, Marginopora vertebralis, to the effects of increased temperature (±3°C) and pCO2 (~1,000 µatm) when associated with its common algal host, Laurencia intricata. Specimens of M. vertebralis were incubated for 15 days in flow‐through aquaria simulating current and end‐of‐century temperature and pH conditions. Physiological measures of growth (change in wet weight), calcification (measured change in total alkalinity in closed bottles), photochemical efficiency (Fv/Fm), total chlorophyll, photosynthesis (oxygen flux), and respiration were determined. When incubated in isolation, M. vertebralis exhibited reduced growth in end‐of‐century projections of ocean acidification conditions, while calcification rates were lowest in the high‐temperature, low‐pH treatment. Interestingly, association with L. intricata ameliorated these stress effects with the growth and calcification rates of M. vertebralis being similar to those observed in ambient conditions. Total chlorophyll levels in M. vertebralis decreased when in association with L. intricata, while maximum photochemical efficiency increased in ambient conditions. Net production estimates remained similar between M. vertebralis in isolation and in association with L. intricata, although both production and respiration rates of M. vertebralis were significantly higher when associated with L. intricata. These results indicate that the association with L. intricata increases the resilience of M. vertebralis to climate change stress, providing one of the first examples of physiological buffering by a marine alga that can ameliorate the negative effects of changing ocean conditions. [ABSTRACT FROM AUTHOR]

The article present an interview with Ricardo Haroun Tabraue, professor of Conservation and Management of Marine Plants at the Universidad de Las Palmas de Gran Canaria (ULPGC). Topics include PLASMAR project aims to define and propose robust scientific methodologies to support Maritime Spatial Planning (MSP) and Blue Growth; conservation of species and relevant marine habitats in the Canary Islands like sebadales, intertidal shallows; and the effects of change climate on marine species.

Poleward expatriation of tropical marine organisms is occurring globally, linked to climate change via strengthening of Western Boundary Currents (WBCs). In summer 2016, there was an unprecedented (in 18 years of monitoring) influx of coral-reef fish juveniles ("vagrants") in temperate SE Australia. However, a large climate change-linked storm event ("East Coast low") in June 2016 wiped out large numbers of these fishes over several days, as well as severely altering coastal habitat. Some taxa (e.g. Acanthuridae: surgeonfishes, key habitat modifiers) were decimated with up to 95% loss, while others (e.g. Pomacentridae: damselfishes, under 5% loss) fared better. The storm altered habitat (boulder "barens" were exposed by large-scale removal of macroalgae) with new barrens supporting over fifty times more tropical fish recruits in the following year (2017) than surrounding kelp-dominated areas. Fish were more vulnerable to storm effects in exposed habitats, and some species exhibited size-selective losses. Such climate-related storms can decouple links between poleward fish shifts and more predictable climate effects such as sea temperature rise. [ABSTRACT FROM AUTHOR]

Southern Ocean waters are among the most vulnerable to ocean acidification. The projected increase in the CO2 level will cause changes in carbonate chemistry that are likely to be damaging to organisms inhabiting these waters. A meta‐analysis was undertaken to examine the vulnerability of Antarctic marine biota occupying waters south of 60°S to ocean acidification. This meta‐analysis showed that ocean acidification negatively affects autotrophic organisms, mainly phytoplankton, at CO2 levels above 1,000 μatm and invertebrates above 1,500 μatm, but positively affects bacterial abundance. The sensitivity of phytoplankton to ocean acidification was influenced by the experimental procedure used. Natural, mixed communities were more sensitive than single species in culture and showed a decline in chlorophyll a concentration, productivity, and photosynthetic health, as well as a shift in community composition at CO2 levels above 1,000 μatm. Invertebrates showed reduced fertilization rates and increased occurrence of larval abnormalities, as well as decreased calcification rates and increased shell dissolution with any increase in CO2 level above 1,500 μatm. Assessment of the vulnerability of fish and macroalgae to ocean acidification was limited by the number of studies available. Overall, this analysis indicates that many marine organisms in the Southern Ocean are likely to be susceptible to ocean acidification and thereby likely to change their contribution to ecosystem services in the future. Further studies are required to address the poor spatial coverage, lack of community or ecosystem‐level studies, and the largely unknown potential for organisms to acclimate and/or adapt to the changing conditions. [ABSTRACT FROM AUTHOR]

Species distribution records are a prerequisite to follow climate-induced range shifts across space and time. However, synthesizing information from various sources such as peer-reviewed literature, herbaria, digital repositories and citizen science initiatives is not only costly and time consuming, but also challenging, as data may contain thematic and taxonomic errors and generally lack standardized formats. We address this gap for important marine ecosystem-structuring species of large brown algae and seagrasses. We gathered distribution records from various sources and provide a fine-tuned dataset with ~2.8 million dereplicated records, taxonomically standardized for 682 species, and considering important physiological and biogeographical traits. Specifically, a flagging system was implemented to signal potentially incorrect records reported on land, in regions with limiting light conditions for photosynthesis, and outside the known distribution of species, as inferred from the most recent published literature. We document the procedure and provide a dataset in tabular format based on Darwin Core Standard (DwC), alongside with a set of functions in R language for data management and visualization. Measurement(s) Species • Distribution Technology Type(s) digital curation Factor Type(s) geographic location Sample Characteristic - Organism Fucales • Laminariales • Tilopteridales • Cymodoceaceae • Hydrocharitaceae • Posidoniaceae • Zosteraceae Sample Characteristic - Environment marine biome Sample Characteristic - Location global Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12011523 [ABSTRACT FROM AUTHOR]

Marine organisms that rely on environmental cues for reproduction are likely to experience shifts in reproductive phenology and output due to global climate change. To assess the role that the environment may play in the reproductive timing for temperate sponges, this study examined sexual and asexual reproduction in New Zealand sponge species (Tethya bergquistae and the Tethya burtoni complex) and correlated reproductive output with temperature, chlorophyll- a concentration, and rainfall. Histological analyses of sponges collected monthly (from February 2015 to February 2017) revealed that these sponges are oviparous and gonochoristic and that they sexually reproduce annually during the austral summer. Both monthly collections and in situ monitoring revealed that Tethya spp. asexually bud continuously, but with greater intensity in the austral spring and summer. Temperature was positively associated with both sexual reproduction and budding, with seasonal cues appearing important. Future shifts in the environment that alter such cues are expected to affect population dynamics of these sponges. [ABSTRACT FROM AUTHOR]

As climate change advances, coastal marine ecosystems are predicted to experience increasingly frequent and intense heatwaves. At the same time, already variable CO2 levels in coastal habitats will be exacerbated by ocean acidification. High temperature and elevated CO2 levels can be stressful to marine organisms, especially during critical early life stages. Here, we used a fully cross-factored experiment to test the effects of simulated heatwave conditions (+ 4 °C) and elevated CO2 (1000 µatm) on the aerobic physiology and swimming performance of juvenile Australasian snapper, Chrysophrys auratus, an ecologically and economically important mesopredatory fish. Both elevated temperature and elevated CO2 increased resting metabolic rate of juvenile snapper, by 21–22% and 9–10%, respectively. By contrast, maximum metabolic rate was increased by elevated temperature (16–17%) and decreased by elevated CO2 (14–15%). The differential effects of elevated temperature and elevated CO2 on maximum metabolic rate resulted in aerobic scope being reduced only in the elevated CO2 treatment. Critical swimming speed also increased with elevated temperature and decreased with elevated CO2, matching the results for maximum metabolic rate. Periods of elevated CO2 already occur in the coastal habitats occupied by juvenile snapper, and these events will be exacerbated by ongoing ocean acidification. Our results show that elevated CO2 has a greater effect on metabolic rates and swimming performance than heatwave conditions for juvenile snapper, and could reduce their overall performance and potentially have negative consequences for population recruitment. [ABSTRACT FROM AUTHOR]

Understanding the response of marine organisms to expected future warming is essential. Large Benthic Foraminifera (LBF) are symbiont bearing protists considered to be major carbonate producers and ecosystems engineers. We examined the thermal tolerance of two main types of LBF holobionts characterized by different algal symbionts and shell types (resulted from alternative biomineralization mechanisms): The hyaline diatom bearing, Amphistegina lobifera, and the porcelaneous dinoflagellate bearing, Sorites orbiculus . To assess the relative contribution of host and symbiont algae to the holobiont thermal tolerance we separately evaluated their response by measuring calcification rates and photosynthetic activity under present-day and future warming scenarios. Our results show that both holobionts exhibit thermal resilience up to 32 °C and sensitivity to 35 °C. This sensitivity differs in the magnitude of their response: calcification of A. lobifera was completely inhibited while it was only reduced in S. orbiculus . Thus, future warming will significantly shift the relative contribution of the two species as carbonate producers. Moreover, A. lobifera exhibited a synchronized response of the host and symbionts. In contrast, in S. orbiculus the symbionts responded prior to the host, possibly limiting its resilience. Our results also demonstrate the role of pre-exposure and acclimation processes of host, symbionts or both in mitigating future warming. It highlights the possibility that while pre-exposure to moderate temperatures benefits the holobiont, in cases of extreme temperature it might reduce its thermal tolerance. [ABSTRACT FROM AUTHOR]

Pyropia is a genus of red algae that is cultivated as a commercial food and is a model organism in marine biotechnology. Its habitat is threatened by global climate change, resulting in considerable interest in developing productive strains that are tolerant to the changing climate. Such strains will be valuable only if they are genetically stable, but introduced genetic traits often are either weakened or completely lost in progeny. To determine and understand the likely fate of a newly acquired trait in Pyropia, we generated PyGUS transgenic P. tenera and analyzed the expression of the transgene and its copy number through its sexual life cycle. The vegetative and diploid cells of parent lines showed stable expression of the PyGUS gene, but approximately 30% of progeny had no histochemical staining for GUS and reduced levels of PyGUS mRNA, even though the transgene was present. Genomic qPCR analysis revealed that the copy number of the PyGUS gene was reduced in gametophyte thalli, which were generated after meiosis. We conclude that the PyGUS gene was markedly unstable during meiosis, and that loss of gene copies and the altered expression of the transgene occurred mostly during meiotic recombination. We anticipate that these results will benefit understanding of molecular mechanisms that confer stability to genetic traits in P. tenera and related species. [ABSTRACT FROM AUTHOR]

Transgenerational plasticity (TGP) may be an important mechanism for marine organisms to acclimate to climate change stressors including ocean warming (OW) and ocean acidification (OA). Conversely, environmental stress experienced by one generation may have detrimental latent effects on subsequent generations. We examined TGP in the embryos and larvae of the pan-tropical sea urchin, Tripneustes gratilla, in response to OA (pH 7.77), OW (+2 °C), or both OA and OW, OAW (+2 °C, pH 7.77) using a parent (F0) generation reared in treatments from the early juvenile to the mature adult, incorporating gonadogenesis and germline differentiation. Embryos and larvae of acclimated parents were reared in all four treatments to the 2-day-old pluteus stage. Larvae from OA and OAW parents were resilient to the effects of acidification, while larvae from OW and OAW parents were more tolerant to warmer temperature (29 °C). Parental acclimation, however, had predominantly negative effects on the size of offspring with reductions in larval arm lengths by as much as 21.4%, while eggs were up to 21.8% smaller in females raised at 29 °C. We highlight the complexity and trade-offs of TGP in this first transgenerational climate change study on a marine macroinvertebrate where the F0 generation was acclimated over their reproductive life. [ABSTRACT FROM AUTHOR]

Ocean warming (OW) and acidification (OA) are intensively investigated as they pose major threats to marine organism. However, little effort is dedicated to another collateral climate change stressor, the increased frequency, and intensity of storm events, here referred to as intensified hydrodynamics. A 2‐month experiment was performed to identify how OW and OA (temperature: 21°C; pHT: 7.7, 7.4; control: 17°C‐pHT7.9) affect the resistance to hydrodynamics in the sea urchin Paracentrotus lividus using an integrative approach that includes physiology, biomechanics, and behavior. Biomechanics was studied under both no‐flow condition at the tube foot (TF) scale and flow condition at the individual scale. For the former, TF disk adhesive properties (attachment strength, tenacity) and TF stem mechanical properties (breaking force, extensibility, tensile strength, stiffness, toughness) were evaluated. For the latter, resistance to flow was addressed as the flow velocity at which individuals detached. Under near‐ and far‐future OW and OA, individuals fully balanced their acid‐base status, but skeletal growth was halved. TF adhesive properties were not affected by treatments. Compared to the control, mechanical properties were in general improved under pHT7.7 while in the extreme treatment (21°C‐pHT7.4) breaking force was diminished. Three behavioral strategies were implemented by sea urchins and acted together to cope with flow: improving TF attachment, streamlining, and escaping. Behavioral responses varied according to treatment and flow velocity. For instance, individuals at 21°C‐pHT7.4 increased the density of attached TF at slow flows or controlled TF detachment at fast flows to compensate for weakened TF mechanical properties. They also showed an absence of streamlining favoring an escaping behavior as they ventured in a riskier faster movement at slow flows. At faster flows, the effects of OW and OA were detrimental causing earlier dislodgment. These plastic behaviors reflect a potential scope for acclimation in the field, where this species already experiences diel temperature and pH fluctuations. [ABSTRACT FROM AUTHOR]