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Litter in the marine environment, in particular plastic, is a significant threat to marine megafauna. Cetaceans are known to ingest or become entangled in marine debris, likely impacting individuals and populations. Southeast Asia is a biodiversity hotspot and harbours a diverse cetacean assemblage. However, there are key knowledge gaps relating to the impact of litter in this region due the lack of experts to survey its vast coastlines. This study aims to address such gaps by using social media, gathering data from Facebook posts relating to cetacean strandings and litter across Southeast Asia between 2009 and 2019. Results show that at least 15 cetacean species have been negatively affected by litter, with ingestion most commonly affecting deep-diving species. Epipelagic and mesopelagic foragers were most vulnerable to entanglement. Davao in the Philippines was identified as a litter-related stranding hotspot. The Irrawaddy dolphin (Orcaella brevirostris) and pygmy sperm whale (Kogia breviceps) are particularly vulnerable to litter. The combination of social media and peer reviewed literature can help build a more complete picture of the spatial distribution of marine litter and the scale of the impact it has on cetacean populations. In this study we provide details of a valuable online tool for helping to understand the impact of marine litter on cetaceans and other charismatic species that are a focus of community engagement.

Background Immunosuppressive treatments inhibit vaccine-induced immunity against SARS-CoV-2. We evaluated whether a 2-week interruption of methotrexate treatment immediately after the COVID-19 vaccine booster improved antibody responses against the S1 receptor-binding domain (S1-RBD) of the SARS-CoV-2 spike protein compared with uninterrupted treatment in patients with immune-mediated inflammatory diseases. Methods We did an open-label, prospective, two-arm, parallel-group, multicentre, randomised, controlled, superiority trial in 26 hospitals in the UK. We recruited adults from rheumatology and dermatology clinics who had been diagnosed with an immune-mediated inflammatory disease (eg, rheumatoid arthritis, psoriasis with or without arthritis, axial spondyloarthritis, atopic dermatitis, polymyalgia rheumatica, and systemic lupus erythematosus) and who were taking low-dose weekly methotrexate (≤25 mg per week) for at least 3 months. Participants also had to have received two primary vaccine doses from the UK COVID-19 vaccination programme. We randomly assigned the participants (1:1), using a centralised validated computer randomisation program, to suspend methotrexate treatment for 2 weeks immediately after their COVID-19 booster (suspend methotrexate group) or to continue treatment as usual (continue methotrexate group). Participants, investigators, clinical research staff, and data analysts were unmasked, while researchers doing the laboratory analyses were masked to group assignment. The primary outcome was S1-RBD antibody titres 4 weeks after receiving the COVID-19 booster vaccine dose, assessed in the intention-to-treat population. This trial is registered with ISRCT, ISRCTN11442263; following the pre-planned interim analysis, recruitment was stopped early. Findings Between Sept 30, 2021 and March 3, 2022, we recruited 340 participants, of whom 254 were included in the interim analysis and had been randomly assigned to one of the two groups: 127 in the continue methotrexate group and 127 in the suspend methotrexate group. Their mean age was 59·1 years, 155 (61%) were female, 130 (51%) had rheumatoid arthritis, and 86 (34%) had psoriasis with or without arthritis. After 4 weeks, the geometric mean S1-RBD antibody titre was 22 750 U/mL (95% CI 19 314–26 796) in the suspend methotrexate group and 10 798 U/mL (8970–12 997) in the continue methotrexate group, with a geometric mean ratio (GMR) of 2·19 (95% CI 1·57–3·04; p Interpretation A 2-week interruption of methotrexate treatment for people with immune-mediated inflammatory diseases resulted in enhanced boosting of antibody responses after COVID-19 vaccination. This intervention is simple, low-cost, and easy to implement, and could potentially translate to increased vaccine efficacy and duration of protection for susceptible groups. Funding National Institute for Health and Care Research.

The goal of sex and gender analysis is to promote rigorous, reproducible and responsible science. Incorporating sex and gender analysis into experimental design has enabled advancements across many disciplines, such as improved treatment of heart disease and insights into the societal impact of algorithmic bias. Here we discuss the potential for sex and gender analysis to foster scientific discovery, improve experimental efficiency and enable social equality. We provide a roadmap for sex and gender analysis across scientific disciplines and call on researchers, funding agencies, peer-reviewed journals and universities to coordinate efforts to implement robust methods of sex and gender analysis. The authors discuss the potential for sex and gender analysis to foster scientific discovery, improve experimental efficiency and enable social equality.

Aquaculture currently accounts for approximately half of all seafood producedand is the fastest growing farmed food sector globally. Marine bivalve aquacul-ture, the farming of oysters, mussels and clams, represents a highly sustainablecomponent of this industry and has major potential for global expansion viaincreased efficiency, and numbers of, production systems. Artificial spat propaga-tion (i.e. settled juveniles) in hatcheries and selective breeding have the potentialto offer rapid and widespread gains for molluscan aquaculture industry. However,bivalves have unique life-histories, genetic and genomic characteristics, whichpresent significant challenges to achieving such genetic improvement. Selectionpressures experienced by bivalve larvae and spat in the wild contribute to drivepopulation structure and animal fitness. Similarly, domestication selection islikely to act on hatchery-produced spat, the full implications of which have not been fully explored. In this review, we outline the key features of these taxa and production practices applied in bivalve aquaculture, which have the potential to affect the genetic and phenotypic variability of hatchery-propagated stock. Along-side, we compare artificial and natural processes experienced by bivalves to investigate the possible consequences of hatchery propagation on stock production. In addition, we identify key areas of investigation that need to be prioritized to continue to the advancement of bivalve genetic improvement via selective breeding. The growing accessibility of next-generation sequencing technology and high-powered computational capabilities facilitate the implementation of novel genomic tools in breeding programmes of aquatic species. These emerging techniques represent an exciting opportunity for sustainably expanding the bivalve aquacul-ture sector

UKAEA has been applying systems engineering for several years; it has provided a unique perspective from which to solve complex engineering challenges, bringing together the insights from all aspects and disciplines involved. Fundamental functional requirements of the systems have been captured and used to develop “solution agnostic” designs (or architecture) of each system at the highest functional level. This has allowed existing preconceptions of the design to be challenged and alternatives solution to be assessed against the abstract system architecture. Systems engineering has also provided a rigorous methodology for recording and tracing the system requirements and associated designs down through multiple hierarchical levels. This paper presents the lessons learned and the benefits seen from applying systems engineering at UKAEA. It presents case studies from the European DEMO, both in the overall design and integration of the power plant as well as within specific work packages. It shows how the top-level work has produced a new perspective on the power plant design. In the work packages of remote maintenance and breeder blankets, it discusses how functional preconceptions and assumptions have been challenged leading to improved designs. It also draws on the experience that RACE (UKAEA) has gained from applying systems engineering to create an optimized design for the European Spallation Source Active Cells Project. We identify the aspects of systems engineering which have been applied to greatest effect and consider both the short-term benefits already realized and the long-term benefits that are anticipated in the future.

The majority of marine invertebrate species release eggs and sperm into seawater for external fertilisation. Seawater conditions are currently changing at an unprecedented rate as a consequence of ocean acidification (OA). Sperm are thought to be particularly vulnerable to these changes and may be exposed to external environmental conditions for variable periods of time between spawning and fertilisation. Here, we undertook a mechanistic investigation of sperm swimming performance in the coastal polychaete Arenicola marina during an extended exposure to OA conditions (pH NBS 7.77, 1000 μatm p CO 2 ). We found that key fitness-related aspects of sperm functioning declined faster under OA conditions i.e. impacts became apparent with exposure time. Sperm swimming speed (VCL), the number of motile sperm and sperm path linearity all dropped significantly after 4 h under OA conditions whilst remaining constant under ambient conditions at this time point. Our results highlight the importance of sperm exposure duration in ocean acidification experiments and may help towards explaining species specific differences in response.

This chapter begins by examining issues to do with associative memory, into which connectionism seems to have injected new life. It discusses four more aspects: the constructive character of recall, concept learning, the effects of damage, and the effects of later learning on earlier learning. Catastrophic interference is clearly a limitation for learning in simple feed-forward networks. Associationism has continued to influence work in animal learning in the form of behaviourism. It should be obvious to anyone familiar with the latter tradition that it has some aspects that are similar to aspects of connectionist learning procedures. The chapter is concerned with what is learned in networks when various learning rules are used in various networks. It aims to focus on some general matters to do with how the learning rules learn. In learning the properties for objects, the network has developed a semantic organisation which distinguishes super-ordinate terms from terms specific to particular exemplars, perhaps much as people do.

Noam Chomsky, in 1959, made a critical and influential attack on the idea that human language might be an example of a stimulus-response relationship, associatively learned by children. Training was carried out using a set of 700 verbs, in which the frequency of occurrence of words in the language was varied in terms of the number of times each verb was included in one run through the training set. Natural language has a well defined syntactic structure which forms the basis of its “compositional semantics”. The rules of grammar specify how the elements of language can be combined, and thereby define the set of legal sequences of symbols or expressions. Fodor and Pylyshyn argue that connectionist networks cannot develop representations that have the combinatorial structure necessary for language processing. If this is the case, connectionist networks cannot be the basis of complete accounts of cognition.

Background: Reactive oxygen species (ROS) arise as a result from, and are essential in, numerous cellular processes. ROS, however, are highly reactive and if left unneutralised by endogenous antioxidant systems, can result in extensive cellular damage and/or pathogenesis. In addition, exposure to a wide range of environmental stressors can also result in surplus ROS production leading to oxidative stress (OS) and downstream tissue toxicity. Objectives: Our aim was to produce a stable transgenic zebrafish line, unrestricted by tissue-specific gene regulation, which was capable of providing a whole organismal, real-time read-out of tissue-specific OS following exposure to a wide range of OS-inducing environmental contaminants and conditions. This model could, therefore, serve as a sensitive and specific mechanistic in vivo biomarker for all environmental conditions that result in OS. Methods: To achieve this aim, we exploited the pivotal role of the electrophile response element (EpRE) as a globally-acting master regulator of the cellular response to OS. To test tissue specificity and quantitative capacity, we selected a range of chemical contaminants known to induce OS in specific organs or tissues, and assessed dose-responsiveness in each using microscopic measures of mCherry fluorescence intensity. Results: We produced the first stable transgenic zebrafish line Tg (3EpRE:hsp70:mCherry) with high sensitivity for the detection of cellular RedOx imbalances, in vivo in near-real time. We applied this new model to quantify OS after exposure to a range of environmental conditions with high resolution and provided quantification both of compound- and tissue-specific ROS-induced toxicity. Discussion: Our model has an extremely diverse range of potential applications not only for biomonitoring of toxicants in aqueous environments, but also in biomedicine for identifying ROS-mediated mechanisms involved in the progression of a number of important human diseases, including cancer. Keywords: Oxidative stress, Zebrafish, Toxicants, Biosensor

This article reviews evidence for the special inhibitory mechanisms required to keep response activation related to affordances of a non-target object from evoking responses. This evidence presents that response activation triggered by affordances of a non-target are automatically inhibited resulting, for example, in decelerated response speed when the response is compatible with the affordance. The article also highlights the neural processes that differentiate these non-target-related affordance effects from other non-target-related effects such as the Eriksen flanker effect that―contrary to these affordance effects―present decelerated response speed when there is incompatibility between the non-target and the response. The article discusses the role of frontal executive mechanisms in controlling action planning processes in these non-target-related affordance effects. It is also proposed that overlapping inhibition mechanisms prevent executing impulsive actions relative to affordances of a target and exaggerate inhibition of response activation triggered by affordances of a non-target.

White Spot Syndrome Virus (WSSV) causes White Spot Disease (WSD) and is historically the most devastating disease in the shrimp industry. Global losses from this disease have previously exceeded $3 bn annually, having a major impact on a global industry worth US$19 bn per annum. Shrimp are cultured predominantly in enclosed ponds that are subject to considerable fluctuations in abiotic conditions and WSD outbreaks are increasingly linked to periods of extreme weather, which may cause major fluctuations in pond culture conditions. Combined with the intensity of production in these systems, the resulting suboptimal physicochemical conditions have a major bearing on the susceptibility of shrimp to infection and disease. Current knowledge indicates that pond temperature and salinity are major factors determining outbreak severity. WSSV appears to be most virulent in water temperatures between 25 and 28 °C and salinities far removed from the isoosmotic point of shrimp. Elevated temperatures (>30 °C) may protect against WSD, depending on the stage of infection, however the mechanisms mediating this effect have not been well established. Other factors relating to water quality that may play key roles in determining outbreak severity include dissolved oxygen concentration, nitrogenous compound concentration, partial pressure of carbon dioxide and pH, but data on their impacts on WSSV susceptibility in cultured shrimps is scarce. This illustrates a major research gap in our understanding of the influence of environmental conditions on disease. For example, it is not clear whether temperature manipulations can be used effectively to prevent or mitigate WSD in cultured shrimp. Therefore, developing our understanding of the impact of environmental conditions on shrimp susceptibility to WSSV may provide insight for WSD mitigation when, even after decades of research, there is no effective practical prophylaxis or treatment.

We examined the spontaneous association between numbers and space by documenting attention deployment and the time course of associated spatial-numerical mapping with and without overt oculomotor responses. In Experiment 1, participants maintained central fixation while listening to number names. In Experiment 2, they made horizontal target-direct saccades following auditory number presentation. In both experiments, we continuously measured spontaneous ocular drift in horizontal space during and after number presentation. Experiment 2 also measured visual-probe-directed saccades following number presentation. Reliable ocular drift congruent with a horizontal mental number line emerged during and after number presentation in both experiments. Our results provide new evidence for the implicit and automatic nature of the oculomotor resonance effect associated with the horizontal spatial-numerical mapping mechanism., Postprints der Universität Potsdam : Humanwissenschaftliche Reihe, 553

We investigated whether top-down expectations about an actor’s intentions affect action perception in a representational momentum (RM) paradigm. Participants heard an actor declare an intention to either take or leave an object and then saw him either reach for or withdraw from it, such that action and intention were either congruent or incongruent. Observers generally misperceived the hand’s disappearance point further along the trajectory than it actually was, in line with the idea that action perception incorporates predictions of the action’s future course. Importantly, this RM effect was larger for actions congruent with the actor’s goals than for incongruent actions. These results demonstrate that action prediction integrates both current motion and top-down knowledge about the actor’s intention. They support recent theories that emphasise the role of prior expectancies and prediction errors in social (and non-social) cognitive processing.

We investigated automatic Spatial-Numerical Association of Response Codes (SNARC) effect in auditory number processing. Two experiments continually measured spatial characteristics of ocular drift at central fixation during and after auditory number presentation. Consistent with the notion of a spatially oriented mental number line, we found spontaneous magnitude-dependent gaze adjustments, both with and without a concurrent saccadic task. This fixation adjustment (1) had a small-number/left-lateralized bias and (2) it was biphasic as it emerged for a short time around the point of lexical access and it received later robust representation around following number onset. This pattern suggests a two-step mechanism of sensorimotor mapping between numbers and space - a first-pass bottom-up activation followed by a top-down and more robust horizontal SNARC. Our results inform theories of number processing as well as simulation-based approaches to cognition by identifying the characteristics of an oculomotor resonance phenomenon.

Ocean acidification (OA) and warming pose a considerable threat to marine ecosystems. Previous studies show that these environmental co-stressors significantly impact upon a number of key physiological functions, including calcification, metabolism and growth, in many marine organisms. Yet despite the importance of the immune system, to date only a handful of studies have investigated the impact of reduced seawater pH on an organism's immune response. Furthermore, whilst temperature has received far greater attention with respect to host defence, there is a dearth of information concerning the possible synergism of these two stressors on immune defence. Here we show that a 90 day exposure to reduced seawater pH led to a reduction in the antibacterial activity of cell-free haemolymph in the blue mussel Mytilus edulis, whilst temperature led to an increase in this immune parameter. However in contrast to previous research, following this initial 90 day exposure, mussels in the current study were then exposed to the pathogenic bacterium, Vibrio tubiashii. Crucially, whilst reduced seawater pH initially appeared to impair immunological functioning, as has been interpreted previously, mussels demonstrated the ability to restore haemolymph bactericidal activity when required. This indicated that the initial reduction in antibacterial activity was in fact a reversible physiological trade-off, rather than an irreversible impairment of immune function. By demonstrating this plasticity, the current study illustrates the need to measure organism responses within a realistic natural context (i.e. measuring the immune response of an organism in the presence of a pathogen). Failure to do so may result in a misleading interpretation of the ecological relevance of experimental data, and thus the sensitivity of different species in a rapidly changing environment.

Human activities are fundamentally altering the chemistry of the world's oceans. Ocean acidification (OA) is occurring against a background of warming and an increasing occurrence of disease outbreaks, posing a significant threat to marine organisms, communities, and ecosystems. In the current study, (1)H NMR spectroscopy was used to investigate the response of the blue mussel, Mytilus edulis, to a 90-day exposure to reduced seawater pH and increased temperature, followed by a subsequent pathogenic challenge. Analysis of the metabolome revealed significant differences between male and female organisms. Furthermore, males and females are shown to respond differently to environmental stress. While males were significantly affected by reduced seawater pH, increased temperature, and a bacterial challenge, it was only a reduction in seawater pH that impacted females. Despite impacting males and females differently, stressors seem to act via a generalized stress response impacting both energy metabolism and osmotic balance in both sexes. This study therefore has important implications for the interpretation of metabolomic data in mussels, as well as the impact of environmental stress in marine invertebrates in general.

Ocean acidification, caused by rising concentrations of carbon dioxide (CO2), is widely considered to be a major global threat to marine ecosystems. To investigate the potential effects of ocean acidification on the early life stages of a commercially important fish species, European sea bass (Dicentrarchus labrax), 12 000 larvae were incubated from hatch through metamorphosis under a matrix of two temperatures (17 and 19 °C) and two seawater pCO2 levels (ambient and 1,000 μatm) and sampled regularly for 42 days. Calculated daily mortality was significantly affected by both temperature and pCO2, with both increased temperature and elevated pCO2 associated with lower daily mortality and a significant interaction between these two factors. There was no significant pCO2 effect noted on larval morphology during this period but larvae raised at 19 °C possessed significantly larger eyes and lower carbon:nitrogen ratios at the end of the study compared to those raised under 17 °C. Similarly, when the incubation was continued to post-metamorphic (juvenile) animals (day 67–69), fish raised under a combination of 19 °C and 1000 μatm pCO2 were significantly heavier. However, juvenile D. labrax raised under this combination of 19 °C and 1000 μatm pCO2 also exhibited lower aerobic scopes than those incubated at 19 °C and ambient pCO2. Most studies investigating the effects of near-future oceanic conditions on the early life stages of marine fish have used incubations of relatively short durations and suggested that these animals are resilient to ocean acidification. Whilst the increased survival and growth observed in this study supports this view, we conclude that more work is required to investigate whether the differences in juvenile physiology observed in this study manifest as negative impacts in adult fish.

Summary Ocean acidification (OA) can shift the ecological balance between interacting organisms. In this study, we have used a model system to illustrate the interaction between a calcifying host organism, the blue mussel Mytilus edulis and a common bivalve bacterial pathogen, Vibrio tubiashii, with organisms being exposed to a level of acidification projected to occur by the end of the 21st century. OA exposures of the mussels were carried out in relative long-term (4 months) and short-term (4 days) experiments. We found no effect of OA on the culturability of V. tubiashii, in broth or in seawater. OA inhibited mussel shell growth and impaired crystalline shell structures but did not appear to affect mussel immune parameters (i.e haemocyte counts and phagocytotic capacity). Despite no evident impact on host immunity or growth and virulence of the pathogen, V. tubiashii was clearly more successful in infecting mussels exposed to long-term OA compared to those maintained under ambient conditions. Moreover, OA exposed V. tubiashii increased their viability when exposed to haemocytes of OA-treated mussel. Our findings suggest that even though host organisms may have the capacity to cope with periods of OA, these conditions may alter the outcome of host–pathogen interactions, favouring the success of the latter.

Two experiments investigated (1) how activation of manual affordances is triggered by visual and linguistic cues to manipulable objects and (2) whether graspable object parts play a special role in this process. Participants pressed a key to categorize manipulable target objects copresented with manipulable distractor objects on a computer screen. Three factors were varied in Experiment 1: (1) the target's and (2) the distractor's handles' orientation congruency with the lateral manual response and (3) the Visual Focus on one of the objects. In Experiment 2, a linguistic cue factor was added to these three factors-participants heard the name of one of the two objects prior to the target display onset. Analysis of participants' motor and oculomotor behaviour confirmed that perceptual and linguistic cues potentiated activation of grasp affordances. Both target- and distractor-related affordance effects were modulated by the presence of visual and linguistic cues. However, a differential visual attention mechanism subserved activation of compatibility effects associated with target and distractor objects. We also registered an independent implicit attention attraction effect from objects' handles, suggesting that graspable parts automatically attract attention during object viewing. This effect was further amplified by visual but not linguistic cues, thus providing initial evidence for a recent hypothesis about differential roles of visual and linguistic information in potentiating stable and variable affordances (Borghi in Language and action in cognitive neuroscience. Psychology Press, London, 2012).

Marine aquaculture relies on coastal habitats that will be affected by climate change. This review assesses current knowledge of the threats and opportunities of climate change for aquaculture in the UK and Ireland, focusing on the most commonly farmed species, blue mussels (Mytilus edulis) and Atlantic salmon (Salmo salar). There is sparse evidence to indicate that climate change is affecting aquaculture in the UK and Ireland. Impacts to date have been difficult to discern from natural environmental variability, and the pace of technological development in aquaculture overshadows effects of climatic change. However, this review of broader aquaculture literature and the likely effects of climate change suggests that over the next century, climate change has the potential to directly impact the industry. Impacts are related to the industry's dependence on the marine environment for suitable biophysical conditions. For instance, changes in the frequency and strength of storms pose a risk to infrastructure, such as salmon cages. Sea-level rise will shift shoreline morphology, reducing the areal extent of some habitats that are suitable for the industry. Changes in rainfall patterns will increase the turbidity and nutrient loading of rivers, potentially triggering harmful algal blooms and negatively affecting bivalve farming. In addition, ocean acidification may disrupt the early developmental stages of shellfish. Some of the most damaging but least predictable effects of climate change relate to the emergence, translocation and virulence of diseases, parasites and pathogens, although parasites and diseases in finfish aquaculture may be controlled through intervention. The spread of nuisance and non-native species is also potentially damaging. Rising temperatures may create the opportunity to rear warmer water species in the UK and Ireland. Market forces, rather than technical feasibility, are likely to determine whether existing farmed species are displaced by new ones.

A wealth of behavioral data has shown that the visual properties of objects automatically potentiate motor actions linked with them, but how deeply are these affordances embedded in visual processing? In the study reported here, we used electrophysiological measures to examine the time course of affordance resulting from the leftward or rightward orientation of the handles of common objects. Participants were asked to categorize those objects using a left- or right-handed motor response. Lateralized readiness potentials showed rapid motor preparation in the hand congruent with the affordance provided by the object only 100 to 200 ms after stimulus presentation and up to 400 ms before the actual response. Examination of event-related potentials also revealed an effect of handle orientation and response-hand congruency on the visual P1 and N1 components. Both of these results suggest that activity in the early sensory pathways is modulated by the action associations of objects and the intentions of the viewer.

Participants viewed video clips of a left or right-handed reach toward an object that was orientated with a handle to the left or right. They were required to classify the object by making a left or right-handed key-press and ignore the reach. These responses were, never-the-less, affected by the observed reach in ways which largely reflected the opportunities for complementary actions in the viewed scenes, given the simultaneous constraints of the object orientation combined with the direction and hand of reach. These influences are claimed to reflect the interdependency of the action possibilities that arise from a set of objects and agents in three-dimensional space that together determine behaviour.

The inception of ecological immunology has led to an increase in the number of studies investigating the impact of environmental stressors on host immune defence mechanisms. This in turn has led to an increased understanding of the importance of invertebrate groups for immunological research. This review discusses the advances made within marine invertebrate ecological immunology over the past decade. By demonstrating the environmental stressors tested, the immune parameters typically investigated, and the species that have received the greatest level of investigation, this review provides a critical assessment of the field of marine invertebrate ecological immunology. In highlighting the methodologies employed within this field, our current inability to understand the true ecological significance of any immune dysfunction caused by environmental stressors is outlined. Additionally, a number of examples are provided in which studies successfully demonstrate a measure of immunocompetence through alterations in disease resistance and organism survival to a realized pathogenic threat. Consequently, this review highlights the potential to advance our current understanding of the ecological and evolutionary significance of environmental stressor related immune dysfunction. Furthermore, the potential for the advancement of our understanding of the immune system of marine invertebrates, through the incorporation of newly emerging and novel molecular techniques, is emphasized.

Our understanding of the effects of ocean acidification on whole organism function is growing, but most current information is for adult stages of development. Here, we show the effects of reduced pH seawater (pH 7.6) on aspects of the development, physiology and behaviour of encap- sulated embryos of the marine intertidal gastropod Littorina obtusata. We found reduced viability and increased development times under reduced pH conditions, and the embryos had significantly altered behaviours and physiologies. In acidified seawater, embryos spent more time stationary, had slower rotation rates, spent less time crawling, but increased their movement periodicity compared with those maintained under control conditions. Larval and adult heart rates were significantly lower in acidified seawater, and hatchling snails had an altered shell morphology (lateral length and spiral shell length) compared to control snails. Our findings show that ocean acidification may have multi- ple, subtle effects during the early development of marine animals that may have implications for their survival beyond those predicted using later life stages.