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Sea level rise (SLR) poses a significant threat to coastal regions worldwide, particularly affecting over 60 million people living below 10 m above sea level along the African coast. This study analyzes the spatio-temporal trends of sea level anomaly (SLA) and its components (thermosteric, halosteric and ocean mass) in the Eastern Tropical Atlantic Ocean (ETAO) from 1993 to 2022. The SLA trend for the ETAO, derived from satellite altimetry, is 3.52 ± 0.47 mm/year, similar to the global average of 3.56 ± 0.67 mm/year. Of the three upwelling regions, the Gulf of Guinea (GoG) shows the highest regional trend of 3.42 ± 0.12 mm/year. Using the ARMORD3D dataset, a positive thermosteric sea level trend of 0.88 ± 0.04 mm/year is observed, particularly in the equatorial and southern Atlantic regions. The steric component drives the interannual SLA variability, while the ocean mass component dominates the long-term trends, as confirmed by the GRACE and GRACE-FO missions for 2002-2022. For those two decades, the total SLR from altimetry amounts to 3.80 ± 0.8 mm/year, whilst the steric component is reduced to only 0.19 ± 0.05 mm/year, leaving a residual increase in the ETAO of 3.69 ± 0.5 mm/year. The independent mass change from GRACE amounts to 2.78 ± 0.6 mm/year for this region, which just closes the sea level budget within present uncertainty levels. Spatial analysis of the steric components indicates a warming along the equatorial African coast including the GoG and a freshening near Angola. Strong correlations with regional climate factors, particularly the Tropical South Atlantic Index, highlight the influence of persistent climate modes. These findings underscore the urgent need for mitigation and adaptation strategies to SLR in the ETAO, especially for densely populated coastal communities., (© 2024. The Author(s).)

The polar cod, Boreogadus saida, is an abundant and ubiquitous forage fish and a crucial link in Arctic marine trophic dynamics. Our objective was to unravel layers of genomic structure in B. saida from Canadian waters, specifically screening for potential hybridization with the Arctic cod, Arctogadus glacialis, large chromosomal inversions, and sex-linked regions, prior to interpreting population structure. Our analysis of 53,384 SNPs in 522 individuals revealed hybridization and introgression between A. glacialis and B. saida. Subsequent population level analyses of B. saida using 12,305 SNPs in 511 individuals revealed three large (ca. 7.4-16.1 Mbp) chromosomal inversions, and a 2 Mbp region featuring sex-linked loci. We showcase population structuring across the Western and Eastern North American Arctic, and subarctic regions ranging from the Hudson Bay to the Canadian Atlantic maritime provinces. Genomic signal for the inferred population structure was highly aggregated into a handful of SNPs (13.8%), pointing to potentially important adaptive evolution across the Canadian range. Our study provides a high-resolution perspective on the genomic structure of B. saida, providing a foundation for work that could be expanded to the entire circumpolar range for the species., (© 2024. Crown.)

Correctional workers (CWs) report high levels of work stressors, frequent exposures to potentially psychologically traumatic events (PPTEs), and substantial mental health challenges. There is evidence of associations between sleep disturbances and diverse mental health challenges, including preliminary evidence from public safety personnel; however, replications and extensions would better inform interventions to support mental health. The current study was designed to examine associations between quality of sleep, work stress, and mental health disorders in a sample of diverse CWs employed in a provincial correctional service in Ontario, Canada. Data were analyzed from 943 CWs who participated in the cross-sectional, web-based Ontario Provincial Correctional Worker Mental Health and Well-Being Study conducted from December 2017 to June 2018. Sleep quality indicators included symptoms of insomnia, total hours of sleep per night on work nights and off-shift nights, number of days feeling rested per week, and overall sleep quality. Descriptive statistics, analyses of variance, correlational analyses, and logistic regression were used to examine relationships among sleep quality, stress of shift work, and mental health disorder symptoms. CWs slept an average of 6.0 h per night when working and 7.2 h during off-shift nights. CWs reported waking up feeling rested an average of 2.6 days per week and rated their overall quality of sleep in the fair to poor range. Many CWs (64.9%) screened positive for clinically significant symptoms of insomnia. There were also differences across occupational groups such that CWs working as correctional officers reported the most sleep problems. There were statistically significant relationships between insomnia and mental health disorder symptoms. Higher levels of stress from shift work were associated with worse sleep quality. CWs, especially those working as correctional officers in a provincial prison, reported many indicators consistent with poorer quality of sleep. Poor quality of sleep was also associated with work stress and mental health disorders., (© 2024. The Author(s).)

Lakes are a crucial source of drinking water, provide ecological services from fisheries and aquaculture to tourism and are also a critical part of the global carbon cycle. Therefore, it is important to understand how lakes are changing over time. The ESA Ocean Colour Climate Change Initiative (OC-CCI) database allows to study changes in the largest lakes over 1997-2023 period. The Caspian Sea and ten next largest lakes were under investigation. Changes in the phytoplankton biomass (Chl-a), the concentration of particulate matter (b bp (555)), the colored dissolved organic matter, CDOM (a dg (412)), and the light diffuse attenuation coefficient in water (K d (490)) were analyzed. Both increasing and decreasing trends (or no significant trend at all) of studied parameters were observed in these lakes over the study period. In some of the Laurentian Great Lakes the changes in CDOM over the study period were found to be in accordance with the lake water level changes i.e. with the inflow from the catchment. There was difference between the trends of Chl-a and b bp (555) in lakes Michigan and Huron indicating that there may have been shift in phytoplankton community that took place around 2005. The study demonstrated that remote sensing products, like the ones created by ESA OC-CCI, are valuable tools to study behavior of large lakes ecosystems over time., (© 2024. The Author(s).)

The movement ecology of European seabass, Dicentrarchus labrax, remains poorly understood, especially in the northern ranges of its distribution. To investigate migration patterns of seabass from the southern North Sea, we combined data from different projects from four countries using various tagging techniques. This resulted in 146 recaptures (out of 5598 externally marked seabass), 138 detected animals (out of 162 seabass fitted with an acoustic transmitter) and 76 archived depth and temperature series (out of 323 seabass with an archival tag). Using geolocation modelling, we distinguished different migration strategies, whereby individual fish migrated to the eastern English Channel (15.1%), the western English Channel (28.3%), the Celtic Sea and the norther part of the Bay of Biscay (17.0%), or stayed in the North Sea (39.6%). A high number of seabass exhibited fidelity to the North Sea (90.5% of recaptures, 55.3% for acoustic transmitters and 44.7% of archival tags). Although seabass are generally considered to migrate southwards in winter, a large number of individuals (n = 62) were observed in the southern North Sea, where spawning might potentially occur in a particular deep location along the coast of Norfolk in the UK. Our results highlight the need to consider fine-scaled population structuring in fisheries assessment, and indicate that current seasonal fisheries closures are not aligned with the ecology of seabass in the North Sea., (© 2024. The Author(s).)

Settlement is a critical period in the life cycle of marine invertebrates with a planktonic larval stage. For reef-building invertebrates such as oysters and corals, settlement rates are predictive for long-term reef survival. Increasing evidence suggests that marine invertebrates use information from ocean soundscapes to inform settlement decisions. Sessile marine invertebrates with a planktonic stage are particularly reliant on environmental cues to direct them to ideal habitats. As gregarious settlers, oysters prefer to settle amongst members of the same species. It has been hypothesized that oyster larvae from species Crassostrea virginica and Ostrea angasi use distinct conspecific oyster reef sounds to navigate to ideal habitats. In controlled laboratory experiments we exposed Pacific Oyster Magallana gigas larvae to anthropogenic sounds from conspecific oyster reefs, vessels, combined reef-vessel sounds as well as off-reef and no speaker controls. Our findings show that sounds recorded at conspecific reefs induced higher percentages of settlement by about 1.44 and 1.64 times compared to off-reef and no speaker controls, respectively. In contrast, the settlement increase compared to the no speaker control was non-significant for vessel sounds (1.21 fold), combined reef-vessel sounds (1.30 fold), and off-reef sounds (1.18 fold). This study serves as a foundational stepping stone for exploring larval sound feature preferences within this species., (© 2024. The Author(s).)

The distribution of symbiotic scleractinian corals is driven, in part, by light availability, as host energy demands are partially met through translocation of photosynthate. Physiological plasticity in response to environmental conditions, such as light, enables the expansion of resilient phenotypes in the face of changing environmental conditions. Here we compared the physiology, morphology, and taxonomy of the host and endosymbionts of individual Madracis pharensis corals exposed to dramatically different light conditions based on colony orientation on the surface of a shipwreck at 30 m depth in the Bay of Haifa, Israel. We found significant differences in symbiont species consortia, photophysiology, and stable isotopes, suggesting that these corals can adjust multiple aspects of host and symbiont physiology in response to light availability. These results highlight the potential of corals to switch to a predominantly heterotrophic diet when light availability and/or symbiont densities are too low to sustain sufficient photosynthesis, which may provide resilience for corals in the face of climate change., (© 2024. The Author(s).)

The sailboat Seaexplorer collected underway sea surface partial pressure of CO 2 (pCO 2 ) data for 129 days (2018-2021), including an Antarctic circumnavigation. By comparing ensembles of data-driven air-sea CO 2 fluxes computed with and without sailboat data and applying a detection algorithm, we show that these sailboat observations significantly increase the regional carbon uptake in the North Atlantic and decrease it in the Southern Ocean. While compensating changes in both basins limit the global effect, the Southern Ocean-particularly frontal regions (40°S-60°S) during summertime-exhibited the largest air-sea CO 2 flux changes, averaging 20% of the regional mean. Assessing the sensitivity of the air-sea CO 2 flux to measurement uncertainty, the results stay robust within the expected random measurement uncertainty (± 5 μatm) but remain undetectable with a measurement offset of 5 µatm. We thus conclude that sailboats fill essential measurement gaps in remote ocean regions., (© 2024. The Author(s).)

The COVID-19 pandemic's early stages severely impacted global fisheries, particularly areas heavily reliant on imported food and tourism like the Galapagos Islands, Ecuador. To contain the spread of the virus, a full lockdown was implemented. However, the collapse of the tourism industry precipitated the worst economic crisis in the history of this multiple-use marine protected area. This paper examines the impact of the pandemic's early stages on consumption patterns and seafood security in the Galapagos from consumers' perspective, drawing on online surveys conducted during the lockdown. Our findings revealed pre-existing seafood insecurity across the archipelago, further exacerbated by the pandemic on the least-populated island. Nevertheless, the seafood system displayed moderated resilience to the pandemic's socioeconomic disruptions. A variety of adaptive responses were adopted by Galapagos residents to cope with the lockdown. Consumers modified their seafood consumption habits, while fishers adapted their harvesting and marketing strategies. Such adaptive responses were shaped by the unique socioeconomic characteristics of each inhabited island and the ability of seafood suppliers to shift from a tourism- and export-oriented to a resident- and domestic-oriented market. This transition has created novel opportunities to foster a systemic transformation of the Galapagos seafood system to enhance its resilience against future crises caused by new pandemics, climate change, or other natural and anthropogenic drivers of change., (© 2024. The Author(s).)

In March 2020, the world went into lockdown to curb the spread of the novel coronavirus (SARS-CoV-2), with immediate impacts on wildlife across ecosystems. The strict 2-year long lockdown in Grand Cayman provided an unprecedented opportunity to assess how the 'human confinement experiment' influenced the community composition of reef fish. Using a suite of multivariate statistics, our findings revealed a stark increase in reef fish biomass during the 2 years of lockdown, especially among herbivores, including parrotfish, with drastic increases in juvenile parrotfishes identified. Additionally, when comparing baseline data of the community from 2018 to the 2 years during lockdown, over a three-fold significant increase in mean reef fish biomass was observed, with a clear shift in community composition. Our findings provide unique insights into the resilience of reef fish communities when local anthropogenic stressors are removed for an unprecedented length of time. Given the functional role of herbivores including parrotfish, our results suggest that reductions in human water-based activities have positive implications for coral reef ecosystems and should be considered in future management strategies., (© 2023. The Author(s).)

The distribution data of 11 soft substrate charophyte and angiosperm species were analyzed. Our study aimed to elucidate the co-occurrence patterns among these sympatric macrophyte species and quantify their distribution areas. The central hypothesis of this study proposed that the observed co-occurrence patterns among the studied species deviate from what would be expected by random chance. Macrophyte occurrence data was derived from an extensive field sampling database. Environmental variables available as georeferenced raster layers including topographical, hydrodynamic, geological, physical, chemical, and biological variables were used as predictor variables in the random forest models to predict the spatial distribution of the species. Permutation tests revealed statistically significant deviations from random co-occurrence patterns. The analysis demonstrated that species tended to co-occur more frequently within their taxonomic groups (i.e., within charophytes and within angiosperms) than between these groups. The most extensive distribution overlap was observed between Chara aspera Willd. and Chara canescens Loisel., while Zostera marina L. exhibited the least overlap with the other species. The mean number of co-occurring species was the highest in Chara baltica (Hartman) Bruzelius while Z. marina had the largest share of single-species occurrences. Based on the distribution models, Stuckenia pectinata (L.) Börner had the largest distribution area., (© 2023. The Author(s).)

The European eel is a facultative catadromous species, meaning that it can skip the freshwater phase or move between marine and freshwater habitats during its continental life stage. Otolith microchemistry, used to determine the habitat use of eel or its salinity history, requires the sacrifice of animals. In this context, blood-based gene expression may represent a non-lethal alternative. In this work, we tested the ability of blood transcriptional profiling to identify the different salinity-habitat histories of European eel. Eels collected from different locations in Norway were classified through otolith microchemistry as freshwater residents (FWR), seawater residents (SWR) or inter-habitat shifters (IHS). We detected 3451 differentially expressed genes from blood by comparing FWR and SWR groups, and then used that subset of genes in a machine learning approach (i.e., random forest) to the extended FWR, SWR, and IHS group. Random forest correctly classified 100% of FWR and SWR and 83% of the IHS using a minimum of 30 genes. The implementation of this non-lethal approach may replace otolith-based microchemistry analysis for the general assessment of life-history tactics in European eels. Overall, this approach is promising for the replacement or reduction of other lethal analyses in determining certain fish traits., (© 2022. The Author(s).)

Marine infectious diseases are a leading cause of population declines globally due, in large part, to challenges in diagnosis and limited treatment options. Mitigating disease spread is particularly important for species targeted for conservation. In some systems, strategic arrangement of organisms in space can constrain disease outbreaks, however, this approach has not been used in marine restoration. Reef building corals have been particularly devastated by disease and continue to experience catastrophic population declines. We show that mixtures of genotypes (i.e., diversity) increased disease resistance in the critically endangered Acropora cervicornis, a species that is frequently targeted for restoration of degraded reefs in the broader Caribbean region. This finding suggests a more generalized relationship between diversity and disease and offers a viable strategy for mitigating the spread of infectious diseases in corals that likely applies to other foundation species targeted for restoration., (© 2022. The Author(s).)

An electrochemical method for detecting the presence of zinc (Zn 2+ ) ions in drinking water was developed using functionalized multi-walled carbon nanotubes (f-MWCNTs) and chitosan (CS). Numerous cylinder-shaped graphene molecules make up f-MWCNTs, which have a high mechanical and electrical conductivity. CS benefits from nanomaterials include biocompatibility, biodegradability, and low toxicity, which are excellent in capacity absorption of metal ions. Dangerous levels of metal ions such as zinc are currently present in drinking water as a result of human and natural activity. Zinc toxicity is associated with a variety of disorders, including Alzheimer's, Parkinson's, diabetes, and cancer. This study incorporated f-MWCNTs and CS with Prussian blue (PB) immobilised on a gold electrode (AuE). Several parameters, including as buffers, pH, scan rate, redox indicator, accumulation time, and volume, were optimised using the cyclic voltammetry (CV) method. According to the CV method, the optimal parameters were phosphate buffered saline (0.1 M, pH 2), 5 mM Prussian blue, 200 mVs -1 scan rate, and 5 s accumulation time. Under ideal circumstances, the differential pulse voltammetry (DPV) method was used to determine the Zn 2+ ions concentration range of 0.2-7.0 ppm. The limit of detection (LOD) was 2.60 × 10 -7  mol L -1 with a correlation coefficient of R 2  = 0.9777. The recovery rate of the developed sensor (f-MWCNTs/CS/PB/AuE) ranged from 95.78 to 98.96%. The developed sensor showed a variety of advantages for detecting Zn 2+ in drinking water, including a quick setup process, quick detection, high sensitivity, and mobility. This study developed the essential sensor for monitoring Zn 2+ levels in drinking water in the future., (© 2022. The Author(s).)

Bacteria in the Shigella genus remain a major cause of dysentery in sub-Saharan Africa, and annually cause an estimated 600,000 deaths worldwide. Being spread by contaminated food and water, this study highlights how wild caught food, in the form of freshwater catfish, can act as vectors for Shigella flexneri in Southern Kenya. A metatranscriptomic approach was used to identify the presence of Shigella flexneri in the catfish which had been caught for consumption from the Galana river. The use of nanopore sequencing was shown to be a simple and effective method to highlight the presence of Shigella flexneri and could represent a potential new tool in the detection and prevention of this deadly pathogen. Rather than the presence/absence results of more traditional testing methods, the use of metatranscriptomics highlighted how primarily one SOS response gene was being transcribed, suggesting the bacteria may be dormant in the catfish. Additionally, COI sequencing of the vector catfish revealed they likely represent a cryptic species. Morphological assignment suggested the fish were widehead catfish Clarotes laticeps, which range across Africa, but the COI sequences from the Kenyan fish are distinctly different from C. laticeps sequenced in West Africa., (© 2022. The Author(s).)

Recent developments in tracking technology resulted in the mapping of various marine spawning migration routes of the European eel (Anguilla anguilla). However, migration routes in the North Sea have rarely been studied, despite many large European rivers and hence potential eel growing habitat discharge into the North Sea. In this study, we present the most comprehensive map to date with migration routes by silver European eels in the North Sea and document for the first time successful eel migration through the English Channel. Migration tracks were reconstructed for 42 eels tagged in Belgium and 12 in Germany. Additionally, some eels moved up north to exit the North Sea over the British Isles, confirming the existence of two different routes, even for eels exiting from a single river catchment. Furthermore, we observed a wide range in migration speeds (6.8-45.2 km day -1 ). We hypothesize that these are likely attributed to water currents, with eels migrating through the English Channel being significantly faster than eels migrating northward., (© 2022. The Author(s).)

Climate change is modifying the hydrological and thermal regimes of rivers worldwide, threatening the triggering of organisms' key life-cycle processes. European eel (Anguilla anguilla) is a critically endangered fish species that migrates over several thousand kilometres between its rearing habitats in continental waters of Europe and North Africa and its spawning area in the Sargasso Sea. Downstream migration of adult eels occurs during periods of decreasing river water temperature associated with high discharge but changes in these environmental cues may affected eel migratory conditions. An innovative multivariate method was developed to analyse long-term datasets of daily water temperature, discharge and eel passage in two European rivers. Over the past 50 years, water temperature and discharge increased in both rivers during the downstream migration period from August to November. Silver eels preferentially migrated at temperatures between 10 and 20 °C combined with high discharge. Environmental changes have resulted in the migration of silver eels under warmer water temperatures. This example illustrates how the changes in environmental cues have led to a growing mismatch between the migratory conditions preferentially selected and those actually used, which may threaten the completion of the eel's life cycle and ultimately the persistence of this already critically endangered species., (© 2021. The Author(s).)

In situ observations of pelagic fish and zooplankton with optical instruments usually rely on external light sources. However, artificial light may attract or repulse marine organisms, which results in biased measurements. It is often assumed that most pelagic organisms do not perceive the red part of the visible spectrum and that red light can be used for underwater optical measurements of biological processes. Using hull-mounted echosounders above an acoustic probe or a baited video camera, each equipped with light sources of different colours (white, blue and red), we demonstrate that pelagic organisms in Arctic and temperate regions strongly avoid artificial light, including visible red light (575-700 nm), from instruments lowered in the water column. The density of organisms decreased by up to 99% when exposed to artificial light and the distance of avoidance varied from 23 to 94 m from the light source, depending on colours, irradiance levels and, possibly, species communities. We conclude that observations from optical and acoustic instruments, including baited cameras, using light sources with broad spectral composition in the 400-700 nm wavelengths do not capture the real state of the ecosystem and that they cannot be used alone for reliable abundance estimates or behavioural studies., (© 2021. The Author(s).)

Bombesin is a putative antibacterial peptide isolated from the skin of the frog, Bombina bombina. Two related (bombesin-like) peptides, gastrin-releasing peptide (GRP) and neuromedin B (NMB) have been found in mammals. The history of GRP/bombesin discovery has caused little attention to be paid to the evolutionary relationship of GRP/bombesin and their receptors in vertebrates. We have classified the peptides and their receptors from the phylogenetic viewpoint using a newly established genetic database and bioinformatics. Here we show, by using a clawed frog (Xenopus tropicalis), that GRP is not a mammalian counterpart of bombesin and also that, whereas the GRP system is widely conserved among vertebrates, the NMB/bombesin system has diversified in certain lineages, in particular in frog species. To understand the derivation of GRP system in the ancestor of mammals, we have focused on the GRP system in Xenopus. Gene expression analyses combined with immunohistochemistry and Western blotting experiments demonstrated that GRP peptides and their receptors are distributed in the brain and stomach of Xenopus. We conclude that GRP peptides and their receptors have evolved from ancestral (GRP-like peptide) homologues to play multiple roles in both the gut and the brain as one of the 'gut-brain peptide' systems.

Anomalous local temperature and extreme events (e.g. heat-waves) can cause rapid change and gradual recovery of local environmental conditions. However, few studies have tested whether species distribution can recover following returning environmental conditions. Here, we tested for change and recovery of the spatial distributions of two flatfish populations, American plaice (Hippoglossoides platessoides) and yellowtail flounder (Limanda ferruginea), in response to consecutive decreasing and increasing water temperature on the Grand Bank off Newfoundland, Canada from 1985 to 2018. Using a Vector Autoregressive Spatiotemporal model, we found the distributions of both species shifted southwards following a period when anomalous cold water covered the northern sections of the Grand Bank. After accounting for density-dependent effects, we observed that yellowtail flounder re-distributed northwards when water temperature returned and exceeded levels recorded before the cold period, while the spatial distribution of American plaice has not recovered. Our study demonstrates nonlinear effects of an environmental factor on species distribution, implying the possibility of irreversible (or hard-to-reverse) changes of species distribution following a rapid change and gradual recovery of environmental conditions.

Underwater Television (UWTV) surveys provide fishery-independent stock size estimations of the Norway lobster (Nephrops norvegicus), based directly on burrow counting using the survey assumption of "one animal = one burrow". However, stock size may be uncertain depending on true rates of burrow occupation. For the first time, 3055 video transects carried out in several Functional Units (FUs) around Ireland were used to investigate this uncertainty. This paper deals with the discrimination of burrow emergence and door-keeping diel behaviour in Nephrops norvegicus, which is one of the most commercially important fisheries in Europe. Comparisons of burrow densities with densities of visible animals engaged in door-keeping (i.e. animals waiting at the tunnel entrance) behaviour and animals in full emergence, were analysed at time windows of expected maximum population emergence. Timing of maximum emergence was determined using wave-form analysis and GAM modelling. The results showed an average level of 1 visible Nephrops individual per 10 burrow systems, depending on sampling time and depth. This calls into question the current burrow occupancy assumption which may not hold true in all FUs. This is discussed in relation to limitations of sampling methodologies and new autonomous robotic technological solutions for monitoring.

Prolonged high-temperature extreme events in the ocean, marine heatwaves, can have severe and long-lasting impacts on marine ecosystems, fisheries and associated services. This study applies a marine heatwave framework to analyse a global sea surface temperature product and identify the most extreme events, based on their intensity, duration and spatial extent. Many of these events have yet to be described in terms of their physical attributes, generation mechanisms, or ecological impacts. Our synthesis identifies commonalities between marine heatwave characteristics and seasonality, links to the El Niño-Southern Oscillation, triggering processes and impacts on ocean productivity. The most intense events preferentially occur in summer, when climatological oceanic mixed layers are shallow and winds are weak, but at a time preceding climatological maximum sea surface temperatures. Most subtropical extreme marine heatwaves were triggered by persistent atmospheric high-pressure systems and anomalously weak wind speeds, associated with increased insolation, and reduced ocean heat losses. Furthermore, the most extreme events tended to coincide with reduced chlorophyll-a concentration at low and mid-latitudes. Understanding the importance of the oceanic background state, local and remote drivers and the ocean productivity response from past events are critical steps toward improving predictions of future marine heatwaves and their impacts.

Plant-pathogen interactions follow spatial and temporal developmental dynamics where gene expression in pathogen and host undergo crucial changes. Therefore, it is of great interest to detect, quantify and localise where and when key genes are active to understand these processes. Many pathosystems are not accessible for genetic amendments or other spatially-resolved gene expression monitoring methods. Here, we adapt single molecule FISH techniques to demonstrate the presence and activity of mRNAs at the single-cell level using phytomyxids in their plant and algal host in lab and field material. This allowed us to monitor and quantify the expression of genes from the clubroot pathogen Plasmodiophora brassicae, several species of its Brassica hosts, and of several brown algae, including the genome model Ectocarpus siliculosus, infected with the phytomyxid Maullinia ectocarpii. We show that mRNAs are localised along a spatiotemporal gradient, thus providing a proof-of-concept of the usefulness of single-molecule FISH to increase knowledge about the interactions between plants, algae and phytomyxids. The methods used are easily applicable to any interaction between microbes and their algal or plant host, and have therefore the potential to rapidly increase our understanding of key, spatially- and temporally-resolved processes underpinning complex plant-microbe interactions.

We studied the fragmentation of conventional thermoplastic and compostable plastic items in a laboratory seawater microcosm. In the microcosm, polyurethane foams, cellulose acetate cigarette filters, and compostable polyester and polylactic acid items readily sank, whereas polyethylene air pouches, latex balloons, polystyrene foams and polypropylene cups remained afloat. Microbial biofilms dominated by Cyanobacteria, Proteobacteria, Planctomycetes and Bacteriodetes grew on the plastics, and caused some of the polyethylene items to sink to the bottom. Electrical resistances (ER) of plastic items decreased as function of time, an indication that seawater had penetrated into microscopic crevices in the plastic that had developed over time. Rate constants for ER decrease in polyethylene items in the microcosm were similar to tensile elongation decrease of polyethylene sheets floating in sea, measured previously by others. Weight loss of plastic items was ≤ 1% per year for polyethylene, polystyrene and polypropylene, 3-5% for latex, polyethylene terephthalate and polyurethane, 15% for cellulose acetate, and 7-27% for polyester and polylactic acid compostable bags. The formation of microplastics observed in the microcosm was responsible for at least part of the weight loss. This study emphasizes the need to obtain experimental data on plastic litter degradation under conditions that are realistic for marine environments.

Ecosystem connectivity is an essential consideration for marine spatial planning of competing interests in the deep sea. Immobile, adult communities are connected through freely floating larvae, depending on new recruits for their health and to adapt to external pressures. We hypothesize that the vertical swimming ability of deep-sea larvae, before they permanently settle at the bottom, is one way larvae can control dispersal. We test this hypothesis with more than [Formula: see text] simulated particles with a range of active swimming behaviours embedded within the currents of a high-resolution ocean model. Despite much stronger horizontal ocean currents, vertical swimming of simulated larvae can have an order of magnitude impact on dispersal. These strong relationships between larval dispersal, pathways, and active swimming demonstrate that lack of data on larval behaviour traits is a serious impediment to modelling deep-sea ecosystem connectivity; this uncertainty greatly limits our ability to develop ecologically coherent marine protected area networks.

The pool of dissolved organic carbon (DOC), is one of the main regulators of the ecology and biogeochemistry of inland water ecosystems, and an important loss term in the carbon budgets of land ecosystems. We used a novel machine learning technique and global databases to test if and how different environmental factors contribute to the variability of in situ DOC concentrations in lakes. In order to estimate DOC in lakes globally we predicted DOC in each lake with a surface area larger than 0.1 km 2 . Catchment properties and meteorological and hydrological features explained most of the variability of the lake DOC concentration, whereas lake morphometry played only a marginal role. The predicted average of the global DOC concentration in lake water was 3.88 mg L -1 . The global predicted pool of DOC in lake water was 729 Tg from which 421 Tg was the share of the Caspian Sea. The results provide global-scale evidence for ecological, climate and carbon cycle models of lake ecosystems and related future prognoses.

Macrocystis pyrifera and Lessonia spicata are economically and ecologically relevant brown seaweeds that recently have been classified as members of two separated families within Laminariales (kelps). Here we describe for the first time the Macrocystis pyrifera x Lessonia spicata hybridization in the wild (Chiloe Island, Southeastern Pacific), where populations of the two parents exist sympatrically. Externally, this hybrid exhibited typical features of its parents M. pyrifera (cylindrical and flexible distal stipes, serrate frond margins and presence of sporophylls) and L. spicata (rigid and flat main stipe and first bifurcation), as well as intermediate features between them (thick unfused haptera in the holdfast). Histological sections revealed the prevalence of mucilage ducts within stipes and fronds (absent in Lessonia) and fully developed unilocular sporangia in the sporophylls. Molecular analyses confirmed the presence of the two parental genotypes for ITS1 nrDNA and the M. pyrifera genotype for two predominantly maternally inherited cytoplasmic markers (COI and rbcLS spacer) in the tissue of the hybrid. A metabolome-wide approach revealed that this hybrid is more chemically reminiscent to M. pyrifera. Nevertheless, several hits were identified as Lessonia exclusive or more remarkably, not present in any of the parent. Meiospores developed into apparently fertile gametophytes, which gave rise to F1 sporophytes that reached several millimeters before suddenly dying. In-vitro reciprocal crossing of Mar Brava gametophytes from both species revealed that although it is rare, interfamilial hybridization between the two species is possible but mostly overcome by pseudogamy of female gametophytes.

In viviparous (live-bearing) animals, embryos face an embryo-specific defecation issue: faecal elimination in utero can cause fatal contamination of the embryonic environment. Our data from the viviparous red stingray (Hemitrygon akajei) reveals how viviparous elasmobranchs circumvent this issue. The exit of the embryonic intestine is maintained closed until close to birth, which allows the accumulation of faeces in the embryonic body. Faecal accumulation abilities are increased by (1) the large intestine size (represents about 400-600% of an adult intestine, proportionally), and (2) the modification in the intestinal inner wall structure, specialized to increase water uptake from the faecal matter. According to the literature, faecal accumulation may occur in embryos of the lamniform white shark as well. The reproductive biology of myliobatiform stingrays and lamniform sharks is characterized by the onset of oral feeding before birth (i.e. drinking of uterine milk and eating of sibling eggs, respectively), which is expected to result in the production of large amounts of faeces during gestation. The strong ability of faecal accumulation in these lineages is therefore likely an adaptation to their unique embryonic nutrition mechanism.

There remain parts of our planet that are seldom visited by humans, let alone scientists. In such locations, crowd-sourced or citizen scientist data can be critical in describing biodiversity and detecting change. Rangitāhua, the Kermadec Islands, are 750 km from the nearest human-habitation. Although our knowledge of this near pristine location has increased with recent biodiversity expeditions, we still lack comprehensive understanding of the marine biodiversity surrounding the islands. In 2015, professional underwater videographers were commissioned to produce a nature documentary focused on Rangitāhua's reefs. We strategically surveyed the raw documentary video and examined how biodiversity estimates differed from traditional scientific surveys. We uncovered three new fish species records for Rangitāhua, extending the known distribution for each species, two of which are also new records for New Zealand waters. Comparison of documentary video footage with scientific survey methods showed that estimates of reef fish species richness from the documentary video were similar to stationary surveys, but lower than non-stationary surveys. Moreover, all survey methods, including documentary video, captured different fish assemblages, reflecting each method's particular bias. Overall, we provide a proof-of-concept for how collaborations between scientists and professional natural historians, such as videographers and photographers, can provide valuable biodiversity information.

StarD7 is a phosphatidylcholine (PC)-specific lipid transfer protein essential for the maintenance of mitochondrial PC composition, morphogenesis, and respiration. Here, we studied the role of StarD7 in skeletal myoblast differentiation using mouse myoblast C2C12 cells and human primary myoblasts. Immunofluorescence and immuno-electron microscopy revealed that StarD7 was distributed in the cytosol, inner mitochondria space, and outer leaflet of the outer mitochondrial membrane in C2C12 cells. Unlike human kidney embryonic cell line HEK293 cells, the mitochondrial proteinase PARL was not involved in the processing and maturation of StarD7 in C2C12 cells. StarD7 was constantly expressed during myogenic differentiation of C2C12 cells. The siRNA-mediated knockdown of StarD7 in C2C12 cells and human primary myoblasts significantly impaired myogenic differentiation and reduced the expression of myomaker, myomerger and PGC-1α. The reduction in mitochondrial PC levels and oxygen consumption rates, decreased expression of myomaker, myomerger and PGC-1α, as well as impaired myogenic differentiation, were completely restored when the protein was reintroduced into StarD7-knockout C2C12 cells. These results suggest that StarD7 is important for skeletal myogenesis in mammals.

Shelf seas play an important role in the global carbon cycle, absorbing atmospheric carbon dioxide (CO 2 ) and exporting carbon (C) to the open ocean and sediments. The magnitude of these processes is poorly constrained, because observations are typically interpolated over multiple years. Here, we used 298500 observations of CO 2 fugacity (fCO 2 ) from a single year (2015), to estimate the net influx of atmospheric CO 2 as 26.2 ± 4.7 Tg C yr -1 over the open NW European shelf. CO 2 influx from the atmosphere was dominated by influx during winter as a consequence of high winds, despite a smaller, thermally-driven, air-sea fCO 2 gradient compared to the larger, biologically-driven summer gradient. In order to understand this climate regulation service, we constructed a carbon-budget supplemented by data from the literature, where the NW European shelf is treated as a box with carbon entering and leaving the box. This budget showed that net C-burial was a small sink of 1.3 ± 3.1 Tg C yr -1 , while CO 2 efflux from estuaries to the atmosphere, removed the majority of river C-inputs. In contrast, the input from the Baltic Sea likely contributes to net export via the continental shelf pump and advection (34.4 ± 6.0 Tg C yr -1 ).

Noise pollution is increasing globally, and as oceans are excellent conductors of sound, this is a major concern for marine species reliant on sound for key life functions. Loud, impulsive sounds from seismic surveys have been associated with impacts on many marine taxa including mammals, crustaceans, cephalopods, and fish. However, impacts across large spatial scales or multiple species are rarely considered. We modelled over 8,000 hours of cetacean survey data across a large marine ecosystem covering > 880,000 km 2 to investigate the effect of seismic surveys on baleen and toothed whales. We found a significant effect of seismic activity across multiple species and habitats, with an 88% (82-92%) decrease in sightings of baleen whales, and a 53% (41-63%) decrease in sightings of toothed whales during active seismic surveys when compared to control surveys. Significantly fewer sightings of toothed whales also occurred during active versus inactive airgun periods of seismic surveys, although some species-specific response to noise was observed. This study provides strong evidence of multi-species impacts from seismic survey noise on cetaceans. Given the global proliferation of seismic surveys and large propagation distances of airgun noise, our results highlight the large-scale impacts that marine species are currently facing.

Thirst has evolved for vertebrate terrestrial adaptation. We previously showed that buccal drying induced a series of drinking behaviours (migration to water-taking water into the mouth-swallowing) in the amphibious mudskipper goby, thereby discovering thirst in ray-finned fish. However, roles of dipsogenic/antidipsogenic hormones, which act on the thirst center in terrestrial tetrapods, have remained unclear in the mudskipper thirst. Here we examined the hormonal effects on the mudskipper drinking behaviours, particularly the antagonistic interaction between angiotensin II (AngII) and atrial natriuretic peptide (ANP) which is important for thirst regulation in mammalian 'forebrain'. Expectedly, intracerebroventricular injection of ANP in mudskippers reduced AngII-increased drinking rate. ANP also suppressed the neural activity at the 'hindbrain' region for the swallowing reflex, and the maintenance of buccopharyngeal water due to the swallowing inhibition may attenuate the motivation to move to water. Thus, the hormonal molecules involved in drinking regulation, as well as the influence of buccopharyngeal water, appear to be conserved in distantly related species to solve osmoregulatory problems, whereas hormonal control of thirst at the forebrain might have been acquired only in tetrapod lineage during evolution.

As algal biotechnology develops, there is an increasing requirement to conserve cultures without the cost, time and genetic stability implications of conventional serial transfers, including issues regarding potential loss by failure to regrow, contamination on transfer, mix up and/or errors in the documentation on transfer. Furthermore, it is crucial to ensure both viability and functionality are retained by stored stock-cultures. Low temperature storage, ranging from the use of domestic freezers to storage under liquid nitrogen, is widely being used, but the implication to stability and function rarely investigated. We report for the first time, retention of functionality in the maintenance of master stock-cultures of an industrially relevant, lipid-producing alga, under a variety of cryopreservation regimes. Storage in domestic (-15 °C), or conventional -80 °C freezers was suboptimal, with a rapid reduction in viability observed for samples at -15 °C and a >50% loss of viability, within one month, for samples stored at -80 °C. No reduction in viability occurred at -196 °C. Post-thaw culture functional performance was also influenced by the cryopreservation approach employed. Only samples held at -196 °C responded to nitrogen limitation in terms of growth characteristics and biochemical profiles (lipid production and chlorophyll a) comparable to the untreated control, cultured prior to cryopreservation. These results have important implications in microbial biotechnology, especially for those responsible for the conservation of genetic resources.

Predictive species distribution models are mostly based on statistical dependence between environmental and distributional data and therefore may fail to account for physiological limits and biological interactions that are fundamental when modelling species distributions under future climate conditions. Here, we developed a state-of-the-art method integrating biological theory with survey and experimental data in a way that allows us to explicitly model both physical tolerance limits of species and inherent natural variability in regional conditions and thereby improve the reliability of species distribution predictions under future climate conditions. By using a macroalga-herbivore association (Fucus vesiculosus - Idotea balthica) as a case study, we illustrated how salinity reduction and temperature increase under future climate conditions may significantly reduce the occurrence and biomass of these important coastal species. Moreover, we showed that the reduction of herbivore occurrence is linked to reduction of their host macroalgae. Spatial predictive modelling and experimental biology have been traditionally seen as separate fields but stronger interlinkages between these disciplines can improve species distribution projections under climate change. Experiments enable qualitative prior knowledge to be defined and identify cause-effect relationships, and thereby better foresee alterations in ecosystem structure and functioning under future climate conditions that are not necessarily seen in projections based on non-causal statistical relationships alone.

The availability of iron (Fe) can seasonally limit phytoplankton growth in the High Latitude North Atlantic (HLNA), greatly reducing the efficiency of the biological carbon pump. However, the spatial extent of seasonal iron limitation is not yet known. We present autumn nutrient and dissolved Fe measurements, combined with microphytoplankton distribution, of waters overlying the Hebridean (Scottish) shelf break. A distinct biogeochemical divide was observed, with Fe deficient surface waters present beyond the shelf break, much further eastwards than previously recognised. Due to along and on-shelf circulation, the Hebridean shelf represents a much-localised source of Fe, which does not fertilise the wider HLNA. Shelf sediments are generally thought to supply large quantities of Fe to overlying waters. However, for this Fe to influence upper-ocean biogeochemical cycling, efficient off-shelf transport mechanisms are required. This work challenges the view that the oceanic surface waters in close proximity to continental margins are iron replete with respect to marine primary production demands.

Sea spray aerosols (SSAs) have profound effects on our climate and ecosystems. They also contain microbiota and biogenic molecules which could affect human health. Yet the exposure and effects of SSAs on human health remain poorly studied. Here, we exposed human lung cancer cells to extracts of a natural sea spray aerosol collected at the seashore in Belgium, a laboratory-generated SSA, the marine algal toxin homoyessotoxin and a chemical inhibitor of the mammalian target of rapamycin (mTOR) pathway. We observed significant increased expression of genes related to the mTOR pathway and Proprotein convertase subtilisin/kexin type 9 (PCSK9) after exposure to homoyessotoxin and the laboratory-generated SSA. In contrast, we observed a significant decrease in gene expression in the mTOR pathway and of PCSK9 after exposure to the natural SSA and the mTOR inhibitor, suggesting induction of apoptosis. Our results indicate that marine biogenics in SSAs interact with PCSK9 and the mTOR pathway and can be used in new potential pharmaceutical applications. Overall, our results provide a substantial molecular evidence base for potential beneficial health effects at environmentally relevant concentrations of natural SSAs.

Analysis of pathogen genome variation is essential for informing disease management and control measures in farmed animals. For farmed fish, the standard approach is to use PCR and Sanger sequencing to study partial regions of pathogen genomes, with second and third-generation sequencing tools yet to be widely applied. Here we demonstrate rapid and accurate sequencing of two disease-causing viruses affecting global salmonid aquaculture, salmonid alphavirus (SAV) and infectious salmon anaemia virus (ISAV), using third-generation nanopore sequencing on the MinION platform (Oxford Nanopore Technologies). Our approach complements PCR from infected material with MinION sequencing to recover genomic information that matches near perfectly to Sanger-verified references. We use this method to present the first SAV subtype-6 genome, which branches as the sister to all other SAV lineages in a genome-wide phylogenetic reconstruction. MinION sequencing offers an effective strategy for fast, genome-wide analysis of fish viruses, with major potential applications for diagnostics and robust investigations into the origins and spread of disease outbreaks.

Using a temporal-dynamic calibrated Ecosim food web model, we assess the effects of future changes on marine resources and ecosystem conditions of the Israeli Mediterranean continental shelf. This region has been intensely invaded by Indo-Pacific species. The region is exposed to extreme environmental conditions, is subjected to high rates of climate change and has experienced intense fishing pressure. We test the impacts of a new set of fishing regulations currently being implemented, a continued increase in sea temperatures following IPCC projections, and a continued increase in alien species biomass. We first investigate the impacts of the stressors separately, and then we combine them to evaluate their cumulative effects. Our results show overall potential future benefits of fishing effort reductions, and detrimental impacts of increasing sea temperature and increasing biomass of alien species. Cumulative scenarios suggest that the beneficial effects of fisheries reduction may be dampened by the impact of increasing sea temperature and alien species when acting together. These results illustrate the importance of including stressors other than fisheries, such as climate change and biological invasions, in an ecosystem-based management approach. These results support the need for reducing local and regional stressors, such as fishing and biological invasions, in order to promote resilience to sea warming.

Xenophyophores, giant foraminifera, are distinctive members of the deep-sea megafauna that accumulate large masses of waste material ('stercomare') within their agglutinated tests, and organise their cells as branching strands enclosed within an organic tube (the 'granellare' system). Using non-destructive, three-dimensional micro-CT imaging we explored these structures in three species from the abyssal eastern Pacific Clarion-Clipperton Zone (CCZ). In Psammina spp., the low-density stercomare occupied much of the test interior, while high-density granellare strands branched throughout the structure. In Galatheammina sp. the test comprised a mixture of stercomare and test particles, with the granellare forming a web-like system of filaments. The granellare occupied 2.8-5.1%, the stercomare 72.4-82.4%, and test particles 14.7-22.5%, of the 'body' volume in the two Psammina species. The corresponding proportions in Galatheammina sp. were 1.7% (granellare), 39.5% (stercomare) and 58.8% (test particles). These data provide a potential basis for estimating the contribution of xenophyophores to seafloor biomass in areas like the CCZ where they dominate the megafauna. As in most xenophyophore species, the granellare hosted huge numbers of tiny barite crystals. We speculate that these help to support the extensive granellare system, as well as reducing the cell volume and lightening the metabolic burden required to maintain it.

Through the current trend for bioprospecting, marine organisms - particularly algae - are becoming increasingly known for their osteogenic potential. Such organisms may provide novel treatment options for osteoporosis and other musculoskeletal conditions, helping to address their large healthcare burden and the limitations of current therapies. In this study, extracts from two red algae - Plocamium lyngbyanum and Ceramium secundatum - were tested in vitro and in vivo for their osteogenic potential. In vitro, the growth of human bone marrow stromal cells (hBMSCs) was significantly greater in the presence of the extracts, particularly with P. lyngbyanum treatment. Osteogenic differentiation was promoted more by C. secundatum (70 µg/ml), though P. lyngbyanum had greater in vitro mineralisation potential. Both species caused a marked and dose-dependent increase in the opercular bone area of zebrafish larvae. Our findings therefore indicate the presence of bioactive components in P. lyngbyanum and C. secundatum extracts, which can promote both in vitro and in vivo osteogenic activity.

The acquisition of environmental osmolality tolerance traits in individuals and gametes is an important event in the evolution and diversification of organisms. Although teleost fish exhibit considerable intra- and interspecific variation in salinity tolerance, the genetic mechanisms underlying this trait remain unclear. Oryzias celebensis survives in sea and fresh water during both the embryonic and adult stages, whereas its close relative Oryzias woworae cannot survive in sea water at either stage. A linkage analysis using backcross progeny identified a single locus responsible for adult hyperosmotic tolerance on a fused chromosome that corresponds to O. latipes linkage groups (LGs) 6 and 23. Conversely, O. woworae eggs fertilised with O. celebensis sperm died in sea water at the cleavage stages, whereas O. celebensis eggs fertilised with O. woworae sperm developed normally, demonstrating that maternal factor(s) from O. celebensis are responsible for hyperosmotic tolerance during early development. A further linkage analysis using backcrossed females revealed a discrete single locus relating to the maternal hyperosmotic tolerance factor in a fused chromosomal region homologous to O. latipes LGs 17 and 19. These results indicate that a maternal factor governs embryonic hyperosmotic tolerance and maps to a locus distinct from that associated with adult hyperosmotic tolerance.

The escalating spread of invasive species increases the risk of disrupting the pathways of energy flow through native ecosystems, modify the relative importance of resource ('bottom-up') and consumer ('top-down') control in food webs and thereby govern biomass production at different trophic levels. The current lack of understanding of interaction cascades triggered by non-indigenous species underscores the need for more basic exploratory research to assess the degree to which novel species regulate bottom-up and/or top down control. Novel predators are expected to produce the strongest effects by decimating consumers, and leading to the blooms of primary producers. Here we show how the arrival of the invasive crab Rhithropanopeus harrisii into the Baltic Sea - a bottom-up controlled ecosystem where no equivalent predators ever existed - appeared to trigger not only strong top-down control resulting in a decline in richness and biomass of benthic invertebrates, but also an increase in pelagic nutrients and phytoplankton biomass. Thus, the addition of a novel interaction - crab predation - to an ecosystem has a potential to reduce the relative importance of bottom-up regulation, relax benthic-pelagic coupling and reallocate large amounts of nutrients from benthic to pelagic processes, resulting in a regime shift to a degraded ecosystem state.