Marine Ecology Progress Series

Climate change and anthropogenic pressures are reshaping marine food webs, altering prey availability and affecting top predators. The European Shag (Gulosus aristotelis), a coastal demersal seabird, provides a valuable model for examining environmentally mediated dietary variation, given its trophic plasticity and capacity to adjust prey use according to local availability, while also allowing assessment of potential demographic consequences. This study investigated spatial and temporal variation in diet at two Portuguese colonies (Berlengas and Arrabida) between 2016 and 2024 and assessed long-term reproductive productivity at Berlengas. A total of 468 regurgitated pellets were analysed, and diet composition was quantified using the Index of Relative Importance (IRI). Generalised additive models were applied to assess environmental, spatial, and period-specific effects on diet composition, while reproductive productivity was modelled in relation to prey biomass. Diet variation was primarily explained by environmental predictors, including sea surface temperature, chlorophyll-a concentration, and zooplankton, whereas year per se had no significant effect, indicating environmentally mediated bottom-up effects. Spatial differences between colonies reflected contrasting prey field structures, and period-specific patterns suggested increased specialisation during breeding. Higher biomass of sandeels (Ammodytidae) was positively associated with reproductive output, whereas shifts toward lower-energy prey were associated with reduced productivity. These findings demonstrate that environmentally driven dietary change has measurable demographic consequences, underscoring the importance of bottom-up processes in shaping seabird population dynamics and informing conservation strategies under ongoing climate change.

Understanding habitat association of animals and how they change through ontogeny is critical to predict the likely effects of habitat change on populations. We investigated how fine scale habitat associations of three common coral reef damselfish species changed among life-stages on reefs surrounding Lizard Island, northern Great Barrier Reef. All three species showed distinct habitat selection at settlement, however the degree to which these initial associations changed through ontogeny were species specific. Pomacentrus amboinensis associated with sandy areas throughout all life-stages; Pomacentrus chrysurus settled to areas with high cover of sand and rubble, but displayed no clear habitat preferences as juveniles or adults. Pomacentrus moluccensis settled to areas with high cover of fine branching corals before shifting to areas with relatively high cover of soft corals as adults. We also compared two different approaches to estimate habitat selection; one that quantified the benthic composition within the approximate home range of individuals versus a more widely used approach of recording a single point underneath the focal individual when they were first observed. Although results were broadly similar, the benthic composition approach revealed details that was overlooked using the single point method. Decreases in the availability of any of these preferred benthic habitats may adversely affect future populations, therefore understanding habitat associations and their transitions among life stages will be crucial in predicting future reef fish communities under ongoing coral loss and habitat change. This will require to systematically study a broader range of species, integrating relevant spatial and temporal scales.

Using linear inverse ecosystem modeling as a data assimilation tool, we compare spawning grounds of Atlantic and Southern Bluefin Tuna (ABT and SBT, respectively) based on results from field campaigns in the Gulf of Mexico (GoM) and eastern Indian Ocean off northwest Australia (Argo Basin). Both regions are warm, stratified, low-nutrient waters dominated by cyanobacteria (Prochlorococcus). Despite these similarities, the Argo Basin is more productive, with [~]1.5X higher net primary production and nearly 2X higher production of top trophic levels in the model (tuna larvae, planktivorous fish, and predatory gelatinous zooplankton). Higher primary production in the Argo Basin is mainly driven by higher N2 fixation and storm mixing of new nutrients in the upper and lower euphotic zone, respectively. Increased ecosystem efficiency (secondary production of top trophic levels / primary production) results from differences in plankton food web organization. In the GoM, protistan zooplankton are the direct consumers of nearly all phytoplankton production. In contrast, higher rates of herbivory by crustaceans feeding on nanophytoplankton combines with a higher impact of appendicularians on cyanobacteria to convert plankton production into larval tuna prey more efficiently in the Argo Basin. Despite similarities in the proportions of phytoplankton production mediated by cyanobacteria and other picoplankton in both systems, food web pathways to larval tuna and other planktivorous fish are substantially shorter in the Argo Basin. Our results highlight the impact of distinct zooplankton ecological niches on ecosystem efficiency and suggest a need for better inclusion of plankton food-web structure in models simulating climate impacts on fisheries production. HIGHLIGHTSO_LIDeveloped food web models of tuna spawning habitat (Indian Ocean & Gulf of Mexico) C_LIO_LISpawning habitats in the Argo Basin and Gulf of Mexico (GoM) are both oligotrophic C_LIO_LIArgo Basin had higher net primary production in part as a result of nitrogen fixation C_LIO_LIArgo Basin had higher rates of direct herbivory by metazoan zooplankton C_LIO_LIThis resulted in greater ecosystem efficiency in the Argo Basin. C_LI

O_LIThe frequency and intensity of heat events is increasing across marine and terrestrial ecosystems. Within the same ecological community, the relative exposure and sensitivity to heat stress may vary considerably among interacting species, like predators and prey. This can be especially true for species that interact at the aquatic-terrestrial interface, as well as for interactions between primarily nocturnal and diurnal species, making it difficult to predict how such communities will respond to habitat warming. C_LIO_LIThermal limit metrics such as CTmax are often assumed to equate with ecological death because such temperatures impair behavioral activity and/or physiological functioning. Prey that are diurnally active can be more frequently exposed to temperatures that approach CTmax compared to their nocturnal predators, which may use thermal refuges during the day. Yet the impacts of daytime heat exposure on nighttime predation risk remain unknown. C_LIO_LIHere, we compared the thermal environment, performance, and heat tolerance between the predatory blue crab, Callinectus sapidus and one of its prey species, the mangrove periwinkle Littoraria anguilifera in a tropical mangrove ecosystem. We examined how exposing prey to heat stress at and below their CTmax affected their capacity to avoid predation in the field at night when predation risk is highest. C_LIO_LIWe found that acute exposure to temperatures near CTmax during the day increased the prey species susceptibility to predation during recovery at night. Although both interacting predator and prey have high thermal tolerance, prey are exposed to conditions that already reach CTmax, suggesting that current extremes in temperatures may already be influencing vulnerability to predation in this ecosystem. C_LIO_LIOur results suggest that differential exposure to sublethal heat stress in diurnal prey relative to their predator, along with the subsequent impact of these exposures on predation risk, will play a role in shaping these interacting as climate warms. C_LI

Many benthic marine invertebrates disperse by releasing microscopic larvae carried by ocean currents to new sites, where they must settle into appropriate habitats and metamorphose to recruit. Species whose larvae settle in response to water-borne chemical cues live in topographically complex habitats. To study whether sinking in response to dissolved cues affects retention of larvae within complex habitats exposed to ambient water flow moving faster than larvae sink, we used the reef-dwelling sea slug, Phestilla sibogae, whose competent larvae stop swimming and sink in response to dissolved cue from their prey coral, Porites compressa. We conducted field experiments where dye-labelled water, neutrally buoyant particles, and larval mimics (particles that sank at the velocity of larvae of P. sibogae) were released together upstream of reefs of branching corals to determine if larval sinking in water above and within a reef affects larval retention within the reef. Wave-driven water flow measured above a reef in the field had instantaneous velocities peaking at 0.3 m s-1, driving slow net advection of water shoreward at [~]0.02 m s-1. Much slower wave-driven flow moved through the interstices within the reef. In this field flow, sinking by larval mimics caused their retention within a reef after dye-labelled water and neutrally buoyant particles had left. Such retention of sinking larvae within topographically complex benthic communities enhances successful recruitment by exposing larvae to high concentrations of cue for long periods, allowing them time to sink to surfaces, adhere, and undergo metamorphosis.

Oxygen minimum zones (OMZs) are among the most significant abiotic environmental gradients found in the ocean. Yet, fine-scale species distribution patterns of organisms inhabiting OMZs are still spatially limited, hindering our understanding on how these oceanographic features influence species diversity and community structure. Cold-water corals are ecologically important habitat-forming species that are often considered to be sensitive to low seawater dissolved oxygen concentration and thus likely to be useful indicators for exploring change in megafaunal abundance and biodiversity across the OMZ. In the eastern tropical Pacific Ocean, widespread oxygen minimum zones and oxygen limiting zones encompass several thousand square kilometers of area and span several hundred meters of the water column, but typically are strongest between 300-700 m depth. A January 2019 cruise aboard the R/V Falkor using the ROV SuBastian, conducted video transects along 7 seamounts between the Costa Rica Margin and Isla del Coco, as well as within one submarine incised canyon on the north side of Isla del Coco. In this study, we analyzed survey data for patterns in cold-water coral species distribution, diversity, and coral community structure relative to abiotic oceanographic variables in order to gain biogeographic insights to this area. Across all sites, we identified 3675 coral occurrences and 75 unique morphospecies between 177-1565 m. Rapid species turnover with increasing depth occurred primarily across the upper (300 m) and lower OMZ boundaries (700 m). Coral assemblages within the OMZ depths were observed to contain distinct groups of species compared to those below at deeper bathyal depths. Stylasterid hydrocorals were disproportionately abundant above and within the OMZ, while octocoral and black coral species dominated in the more well-oxygenated waters below. Coral assemblage diversity and abundance was depressed within the OMZ, but bathyal diversity peaked at intermediate water depths between 1200-1500 m. In addition to assessing the impact of OMZs on coral communities, these results provide unique insights to the abundance, diversity, and environmental drivers of deep-water coral community assembly in a data-deficient locality, thus improving biodiversity metrics and informing marine conservation efforts off Costa Rica. These baseline data are particularly salient in the light of projected expansion and shoaling of eastern tropical Pacific oxygen minimum zones as a result of decreasing ocean oxygen concentrations driven by ocean warming and other climate drivers.

The long-standing misconception that the Galapagos petrel (Pterodroma phaeopygia) and the Hawaiian petrel (Pterodroma sandwichensis) were conspecific masked the severe vulnerability of the Galapagos population. By the time its distinct status was recognized, the Galapagos petrel was already in marked decline, primarily due to invasive predators. Consequently, sustained rodent control programs have been implemented on Santa Cruz Island. An unintentional one-year failure in rodent control provided a rare quasi-experimental opportunity to quantify the demographic consequences of the invasive black rat predator. During this year, hatching success declined by [~]35% and breeding success by [~]40% relative to long-term means (66% and 62%, respectively), representing a substantial reproductive collapse. Fledging success exhibited a comparatively modest decline (from a long-term mean of 94% to 86% in 2017), suggesting stage-specific vulnerability. These results support the hypothesis that invasive black rats primarily affect early reproductive stages through egg predation and predation on small chicks, while older chicks surpass a critical size threshold that reduces susceptibility. Across the remaining managed years, reproductive metrics exhibited great stability, demonstrating the petrels resilience against other environmental or climatic stressors. Our findings provide robust empirical evidence that invasive rodent control is the dominant driver of reproductive success in this endangered seabird. The quasi-experimental failure underscored both the effectiveness and the necessity of continuous predator management, highlighting the severe and immediate consequences of even short-term lapses.

Seamounts are prominent deep-ocean features that strongly influence geological processes, ocean circulation, and benthic biodiversity. Despite their importance, most seamounts remain unmapped and poorly characterized, particularly in the southeast Pacific Ocean, a region recognized for high marine endemism and ecological isolation. In this study, we present a quantitative habitat characterization of a previously undocumented seamount, informally named Solito Seamount, located between the Nazca-Desventuradas Marine Park and the Juan Fernandez Archipelago. High-resolution multibeam bathymetry and backscatter intensity data were integrated with in situ observations from two remotely operated vehicle (ROV) dives (SO643 and SO645) to investigate how geomorphology and substrate distribution influence benthic community patterns. An automated and hierarchical quantitative mapping framework incorporating objective terrain analysis and multivariate statistical techniques, including principal component analysis and clustering, was applied to delineate five distinct megahabitat types: flat, basal slope, valley, ridge slope, and ridge crest. ROV video transects traversing these megahabitats revealed five associated substrate type forming macrohabitats: bedrock, bedrock with sediment veneer, sediment-rock transition, sediment, and coral rubble. Outputs were used to investigate how environmental heterogeneity structures megafaunal assemblages of Solito Seamount. Multivariate analysis revealed a combined effect of megahabitat type and substrate type on benthic megafaunal assemblages across the depth gradient. These compositional dissimilarities were primarily driven by habitat-forming taxa. In the deeper dive (SO643), a broad suite of taxa contributed to dissimilarities, and assemblages were primarily organised by megahabitat. The ridge crest hosted a distinct reef-building scleractinian community, whereas the ridge slope hosted mixed antipatharian, gorgonian and actiniarian assemblages. In contrast, the shallower dive exhibited simpler patterns with few taxa driving dissimilarities. Substrate effects were most pronounced with coral rubble forming a distinct habitat characterised by sponges (Stelletta sp.). Pronounced biological differences between dives may also represent depth-dependent structuring resulting from differences in oxygen regimes associated with water masses, underscoring the role of oceanographic forcing. This study provides the first quantitative habitat map of this previously undocumented seamount, delivering essential baseline information for this largely unexplored region of the southeast Pacific. The integrated multi-scale geophysical and biological approach presented here offers a robust framework for advancing seamount ecosystem understanding and supporting future biodiversity assessments and conservation planning.

Encounter rate models are important tools for evaluating and estimating trophic interactions between species. While encounter rate parameters have been measured for many freshwater pelagic fishes, most benthic fishes remain mostly unstudied. Those few efforts to generate encounter rate models for benthic fishes often hold mathematical assumptions based on visual foraging, despite the many cases in which benthic fishes employ the lateral line to forage. Furthermore, encounter rate models are rarely compared, despite the many cases in which prey animals face predation risk from multiple types of predators. For example, the macroinvertebrate Mysis is exposed to both benthic and pelagic predation risk during diel vertical migration (DVM). Comparing the risks between habitats could help evaluate predation risk as an ultimate cause of their DVM behavior. We created a novel encounter rate model based on lateral line ("tactile") foraging by sculpins (Cottidae) given the saltatory (stop-and-go) nature of their movement. The tactile model demonstrated variation in behavior and peak encounter rate with detection distance, movement velocity, and rest durations. We then directly compared predation risk for Mysis by parameterizing both our tactile benthic (2D) encounter rate model for sculpin and a visual pelagic (3D) for rainbow smelt (Osmerus mordax). Tactile encounter rates were generally lower than visual rates for individual predators. However, population level encounter rates at night were greater in the benthic habitat than the pelagic habitat. Overall, our model estimates of encounter rates were consistent with the long-standing hypothesis that predation is an ultimate driver of DVM behavior.

Mid-Trophic Level (MTL) organisms--including krill, forage fish, and mesopelagic fish-- are abundant in the California Current System (CCS) and play an essential role in transferring energy and biomass from primary producers to top predators. However, their spatiotemporal distribution and variability remain poorly understood, particularly with respect to vertical structure across epipelagic and mesopelagic habitats and coastal-offshore gradients. This lack of understanding emerges from both the complexity of MTL interactions with a heterogeneous environment and the challenges associated with sampling these organisms at high spatial and temporal resolution. To address this gap, we analyze 11 years of fisheries acoustic observations in the CCS (2006-2016) to characterize the spatiotemporal dynamics of MTLs as inferred from acoustic backscatter. Acoustic observations at 38 and 120 kHz, collected during day and night across depth strata from 15 to 495 m, reveal consistent cross-shore, seasonal, and latitudinal patterns in the backscatter of acoustically defined zooplankton, epipelagic fish, and mesopelagic fish communities. These patterns include: (1) weaker cross-shore gradients in mesopelagic relative to epipelagic communities; (2) a temporal succession among communities associated with seasonal upwelling; and (3) a multimodal latitudinal distribution with distinct coastal backscatter peaks. We further investigate relationships between acoustic backscatter and co-located environmental variables from in situ, remote sensing, and reanalysis products to elucidate plausible mechanisms underlying MTL dynamics. HighlightsO_LIFisheries acoustics resolve variability in mid-trophic communities C_LIO_LIEleven years of backscatter reveal consistent patterns in the California Current C_LIO_LIEpipelagic backscatter declines faster from the coast to offshore than mesopelagic C_LIO_LISeasonal changes in community composition are linked to upwelling dynamics C_LIO_LIBackscatter exhibits multimodal latitudinal distributions with distinct peaks C_LI

Ocean warming is altering abiotic environments and biotic interactions experienced by marine organisms, where sensitive early developmental windows occur in biologically complex seawater communities. The impact of these interactions on developmental processes and fitness in hosts is not well understood, but likely contingent on the establishment of a host-associated microbiome. Here, we hypothesize that temperature and microbial exposure during embryogenesis influence larval microbiome assembly and host morphology. Strongylocentrotus purpuratus embryos were raised in low microbial richness (LMR) or high microbial richness (HMR) seawater at ambient (14 {degrees}C) or elevated (18 {degrees}C) temperature, then collected at 2, 4, and 6 days post-fertilization (dpf) following multiple feedings. Higher microbial diversity was observed in larvae that developed in HMR seawater when compared to LMR. Differences in relative abundances of dominant microbial families between seawater and larvae suggest some degree of host selectivity in microbiome assembly. Temperature did not strongly alter microbiome composition, but both temperature and microbial condition led to differences in larval morphology by 6 dpf, potentially due to enrichment of microbes with chemoheterotrophic functions. By linking how temperature and microbial communities interact with host development, we contribute novel insights into how early-life environmental conditions impact holobiont formation and morphology. One sentence summaryEarly developmental temperature and microbial conditions shape larval microbiome establishment and morphology.

Calcein is a fluorescent marker commonly used to label growing calcified structures in marine organisms, but its efficacy is species- and context-specific. We evaluated calcein marking success and survival in the common periwinkle (Littorina littorea) during winter in the Gulf of Maine. Snails were immersed for 24 h in seawater containing 0, 50, or 100 mg L-1 calcein and scored for fluorescent marks 22 days later. Overall marking success was low (12.5% of exposed snails evaluated) but was strongly size-dependent: each 1 mm increase in shell length reduced the odds of acquiring a mark by 27%. Among exposed snails, higher calcein concentration (100 mg L-1) produced significantly brighter marks than the lower concentration (50 mg L-1). Survival was 100% across all treatments. The low overall marking rate likely reflects suppressed shell growth at winter temperatures. We recommend 100 mg L-1 calcein with a 24-h immersion for marking L. littorea and suggest that marking during warmer months would improve efficacy across a broader size range.

Accurate estimation of post-release survival is fundamental to fisheries stock assessment and effective management. Conventional tag-return studies and acoustic telemetry are commonly used to estimate this probability, yet each approach has limitations when applied independently. Using gag (Mycteroperca microlepis) as a case study, we integrated data from a large-scale conventional tagging program and an acoustic telemetry experiment within a discrete-time statistical modeling framework that links relative recapture risk with telemetry-derived fate. This approach enabled estimation of post-release survival across a broad gradient of capture depths representative of recreational fishing conditions. Estimated survival was high in shallow waters ({approx}97%) but declined with increasing capture depth, consistent with depth-related barotrauma. Applying model predictions to depth distributions from the recreational fishery yielded annual and monthly post-release survival probabilities. Annual estimates were consistent with values assumed in recent stock assessments, while monthly values highlighted seasonal patterns potentially relevant for management. This integrated framework advances post-release survival estimation by combining the extensive sample sizes and environmental coverage characteristic of conventional tagging data with the direct fate observations provided by acoustic telemetry, and offers a transferable approach for other highly targeted fisheries.

Reef manta rays (Mobula alfredi) are threatened by fishing and other anthropogenic threats. Which, when coupled with conservative life history traits, have made this species vulnerable to extinction. Spatiotemporal ecological knowledge, such as site fidelity and visitation patterns to key aggregation sites, are imperative for effective conservation management of M. alfredi. A novel method of environmental sensing, remote underwater photo systems (RUPs), was employed to understand drivers of M. alfredi habitat use and resighting patterns. RUPs were deployed at four cleaning sites around Laamu Atoll, Maldives. Between March 2021 and May 2023, 455,458 photos were analysed. Generalised linear models revealed increases in M. alfredi presence in response to high chlorophyll-a concentrations, low illumination moon states, the Southwest Monsoon, and in the morning, while human presence had no effect. Branchial spot patterns allowed for 81 M. alfredi individuals to be identified, from 629 sightings, representing 51.59% of Laamu Atolls previously identified population (n = 157). Cleaning stations are visited more intensively during periods of increased productivity of the Southwest Monsoon, likely in response to greater foraging opportunities near the study areas. Additionally, moon state, used as a proxy for tidal strength, was associated with increased visitation during new moon periods, suggesting that weaker tidal states may facilitate presence. These data support integrating RUPs with observational surveys to improve inferences about habitat use and our understanding of cleaning sites frequented by M. alfredi. This study aims to inform the implementation of Laamu Atolls first marine protected area management plan.

Nutrient availability, ecosystem productivity, and consumer assemblages are intricately linked through complex interactions and feedbacks. Nutrients influence the diversity and functional roles of consumers via shifts in resource quality and quantity, and consumers can alter ecosystem production and nutrient availability. However, our understanding of how characteristics of consumers respond to and influence concomitant shifts in nutrient availability and production is limited. We quantified the response of well-studied consumer assemblages (benthic invertebrates and zooplankton) to realistic nutrient loads that altered gross primary production (GPP) and ecosystem respiration (ER). We fertilized 14 outdoor experimental ponds for 2 months and monitored total water column carbon (TC), nitrogen (TN), and phosphorus (TP), GPP, ER, and net ecosystem production (NEP) weekly. Then, we evaluated how fertilization and the variation in nutrients and metabolism caused by fertilization were related to shifts in consumer assemblages. Fertilization increased water column TN and TP and reduced TC:TP ratios, TN:TP ratios, and rates of GPP and ER. However, consumer assemblages were more tightly linked to variation in nutrient availability and production across ponds than to fertilization. Greater declines in benthic diversity occurred in ponds with higher average TN:TP ratios during the experiment. Consistent with predicted effects of cladocerans on nutrient availability, shifts in cladoceran abundances were positively associated with average water column TN:TP ratios during the experiment. Finally, elevated GPP and ER were associated with greater increases in the abundance of benthic invertebrate predators, suggesting the possibility of top-down control. Our study highlights the critical role of consumer-mediated processes in the interaction between nutrient availability and production. Manuscript HighlightsO_LIFertilization reduced pond gross primary production and ecosystem respiration rates. C_LIO_LIInvertebrate predator abundance was inversely related to gross primary production. C_LIO_LIShifts in consumer assemblages were tightly linked to nutrients and production. C_LI

Vessel-whale collisions are a growing global concern and remain challenging to quantify. Therefore, the use of proxies, such as Close Encounters (CEs) that comprise Surprise Encounters (SEs) and Near-Miss Events (NMEs), has been proposed and widely employed to assess collision risk. To better understand this risk in the Eastern North Atlantic, where maritime traffic is intensive, this study aimed to redefine and quantify CEs, and to assess detectability-related variables that may affect CE identification. CEs were assessed using a cetacean occurrence dataset collected between 2012 and 2024 on board cargo ships and oceanographic vessels. CEs thresholds were redefined based on Time to Potential Collision (TPC), rather than distance alone (as described in literature), to allow a more dynamic, risk-based, and speed-sensitive approach. In total, 1226 sightings of whales (baleen, sperm, and beaked whales) were recorded, of which 37.4% were classified as SEs and 2.0% as NMEs. The sperm whale, Physeter macrocephalus, was the species most frequently involved in CEs (13.9% of all CEs), followed by the Cuviers beaked whale, Ziphius cavirostris (11.8%). A Generalized Additive Model was used to assess the influence of detectability-related variables (i.e., meteorological conditions, whale taxa, vessel characteristics, and Marine Mammals Observers (MMOs) experience) on TPC. Significantly lower TPC values were observed with beaked whales, cargo ships, poor visibility conditions, and less experienced MMOs. The results of this study provide an CEs assessment in this region and contribute to the ongoing efforts to standardize CE quantification, by using TPC as a metric. This work also highlights the importance of decreased speeds and the presence of experienced MMOs on board to increase detection probability and TPC, thereby potentially minimizing collision risk.

Wind has a strong influence on the flight characteristics, movements, energetics, demography, life-history traits and biogeography of flying animals. With climate change affecting atmospheric circulation patterns at different time scales, understanding the links between wind and animal movements is crucial for predicting its impact on flying biodiversity. Most studies on the relationship between wind and seabird movements have, however, focused on local scales, exploring birds perceptive sensitivity to local wind. In this study, we examine low-level wind pattern oscillations in the Southern Indian Ocean at multiple time scales to explain the local- to large-scale movements of the Amsterdam albatross. Adult individuals exhibited smooth trajectories, strongly correlated with seasonal, intra-seasonal or interannual wind oscillations. Conversely, younger individuals displayed more erratic and exploratory movements, often being swept away by eastward moving low-pressure systems at a synoptic time scale. Our results suggest that Amsterdam albatrosses can learn and adapt to the annual and monthly low-level wind climatology and interannual variability of the Southern Indian Ocean. This also highlights the importance of investigating seabird movements in relation to broader-scale wind patterns to support their conservation in a changing climate due to human activities. A robust assessment of regional circulation response to climate change for upcoming decades could help project the impact of climate change on seabird movements and mitigate its effects.

Benthic remineralization of organic matter is key to carbon and nutrient cycling, influencing both long-term carbon storage in the sediments and the release of nutrients that support primary production in the water column. With its multiple forms and ages of sea ice, Nares Strait in the Canadian Arctic offers a unique opportunity to address the knowledge gap of variability of benthic remineralization rates along a natural sea ice gradient. Here, we incubated sediment cores in different locations in Nares Strait characterised by different sea ice conditions ranging from first-year ice to multi-year ice, to measure oxygen and nutrient fluxes. To identify potential drivers, we measured environmental variables, identified macrofauna and calculated a suite of taxonomic and functional diversity indices. Our analyses showed that benthic fluxes varied significantly between the northern and southern regions of Nares Strait. The presence of deposit feeders and sea ice cover (number of days since ice-free) were the main drivers in benthic fluxes, explaining 22.6% and 13.9% of the benthic flux variation, respectively. Overall, functional diversity was a better predictor of benthic fluxes than taxonomic diversity, indicating its primary importance in controlling benthic ecosystems functioning. Our results reveal that, from a benthic biogeochemical point of view, Nares Strait seems to be dissected into two main sub-regions: (i) a permanently and highly sea ice-covered area north of Kennedy Channel, resembling deeper regions of the Arctic Ocean and (ii) a seasonally ice-covered area between the North Water Polynya and Kane Basin, where benthic fluxes values are equivalent to those reported in similar continental Arctic shelves. Consequently, the rapid functional shifts resulting from the ongoing decline in sea ice could enhance benthic remineralisation rates if deposit feeder were to become dominant in certain areas, reducing the role of the region and by extension, the Arctic, as a carbon sink.

Artificial light at night is a rapidly increasing driver of global change, affecting both astronomical observations and biodiversity. Regulations such as the Canary Islands "Sky Law" were designed to protect astronomical observations by controlling light intensity and spectral composition, yet their ecological effectiveness remains largely untested. Here, we experimentally assessed whether lighting conditions permitted under this law influence the behaviour of two sensitive nocturnal taxa: seabirds and bats. Field experiments were conducted in Tenerife, Canary Islands, using controlled lighting treatments that varied in intensity (low vs. high) and spectrum (PC amber ~1800K vs. white ~2700K), including a no-light control. We monitored the behaviour of breeding adult Corys shearwaters (Calonectris borealis) using GPS tracking and passive acoustic recording, and quantified bat activity through ultrasonic detectors. Behavioural responses included flight characteristics, colony attendance, vocal activity in shearwaters, and species-specific movement and feeding activity in bats. Generalised linear mixed models were used to evaluate treatment effects while accounting for environmental covariates. Across 211 shearwater flights and extensive acoustic datasets, we found no consistent or significant effects of light treatments on seabird flight behaviour, vocal activity, or bat movement and feeding activity. Instead, environmental variables such as moonlight, seasonality, and interannual variation were stronger predictors of behavioural responses. These results suggest that lighting conditions currently permitted under the Sky Law may have limited ecological impact on the studied taxa under the conditions tested. Further research in less disturbed environments and with broader spectral contrasts is needed to better assess the ecological implications of astronomically motivated lighting regulations.

The queen conch (Aliger gigas) is a key native species of the Caribbean Sea and a primary source of income for thousands of fishers. Historically, it has been a highly valuable resource for the fishing sectors of countries such as the Bahamas, Turks and Caicos, Honduras, and Nicaragua. However, due to its high economic value, the species has been extensively overfished across the region. Overfishing, combined with limited larval dispersal, low recruitment, and poor population connectivity, has led to a drastic decline in population numbers of the species, resulting in its current classification as Threatened. Despite this status, likely impacts of climate change on its populations remain poorly understood, posing significant challenges to conservation efforts. To address this gap, we integrated occurrence records, climate data, and satellite-derived marine habitat data to develop ecological niche models estimating the current and future distribution of the queen conch under different climate change scenarios. We found substantial losses of suitable areas for queen conch along the northern Atlantic coast of South America and Central America, part of the Greater Antilles and the Lesser Antilles. The entire Caribbean region is projected to lose suitability entirely within 20-30 years under the moderate and most extreme climate scenarios. Conversely, our models estimate some suitable areas to persist or expand along the southeastern coast of the United States at least until sometime between 2040 and 2060. Overall, our results suggest a northward shift in the range of this species, with the magnitude of this shift closely tied to the severity of climate change impacts. This work aims to build upon and enhance existing knowledge about survival of queen conch populations in the Caribbean over time. Anticipating future habitat availability will be key to protecting this economically and ecologically important species.