Ellen Kenchington

Sea pen fields function as critical biogenic structures that add three-dimensional complexity to soft-sediment habitats, making them priority targets for marine conservation and subsequent monitoring. However, the capacity of certain species to completely retract beneath the sediment introduces a significant detection bias into non-invasive visual surveys. To quantify these autogenic retraction dynamics, two high-resolution camera-equipped benthic landers were deployed 600 m apart within the Gully MPA (northwest Atlantic) from October 2022 to July 2023, capturing seafloor images at 30-min intervals. Image time-series from the primary site, dominated by the sea pen Pennatula aculeata , were analyzed using a combination of manual annotations (Lightroom, BIIGLE) and supervised machine learning pixel-segmentation (RootPainter). While individual P. aculeata colonies remained visible across 70–90% of the frames, distinct group retraction events occurred in approximately 1.5% of the imagery, during which at least 97% of the localized population simultaneously withdrew into the sediment. Random Forest modeling identified semilunar cycles (~14.7-day intervals) as a primary driver of these synchronized retractions, with behavioural periodicities heavily coupled to tidally driven forcing during the autumn. Conversely, winter and spring months exhibited high, sustained colony expansion, potentially mediated by seasonal pulses of high-quality organic matter confirmed by sediment trap biomarker fluxes. Density- and size-dependent cues and diel rhythms were not primary drivers. These findings demonstrate that optical detection probability varies significantly by season and lunar phase; standardizing visual censing frameworks to explicit temporal windows will mitigate non-random sampling absences and substantially enhance the statistical power of deep-sea conservation monitoring.

Geodia hentscheli, a species forming sponge grounds in the North Atlantic and Arctic Oceans, is a common deep-sea organism, that plays a fundamental role in forming biogenic habitats. However, there is little information about gene flow and adaptation patterns of this species, which is crucial to develop effective management/conservation plans under current global change scenarios. Here, we generated ddRADseq data from 110 specimens of G. hentscheli, together with microbial profiling, transcriptomics, and metatranscriptomics for a selection of specimens to investigate their genetic diversity, molecular connectivity, and local adaptations. Sampling covered the species' entire distribution within a wide bathymetric range. We obtained 1,115 neutral SNPs and identified long-distance genetic connectivity among regions separated 1,000s of km, but strong genetic structure segregating populations by depth at ca. 1,300 m, in line with our microbial analyses. Coalescent analyses inferred the split of these depth-related genetic entities ∼10 KYA, coincident with the last postglacial maximum. Analyses of SNPs under selection, combined with transcriptomic and metatranscriptomic data highlight the presence of several sponge genes and microbial metabolic pathways involved in adaptation to depth, including heat shock proteins and fatty acids, among others. The physiological plasticity of the sponge and its microbiome as a function of depth suggest the existence of a host-microbiome metabolic compensation for G. hentscheli. This study provides a multiscale paradigmatic example of the depth-differentiation hypothesis, a phenomenon mainly caused by changes in environmental conditions at different depths, mainly related to the presence of water masses with different characteristics that drive local adaptations.

Aim: The urgency for remote, reliable and scalable biodiversity monitoring amidst mounting human pressures on ecosystems has sparked worldwide interest in Passive Acoustic Monitoring (PAM), which can track life underwater and on land. However, we lack a unified methodology to report this sampling effort and a comprehensive overview of PAM coverage to gauge its potential as a global research and monitoring tool. To address this gap, we created the Worldwide Soundscapes project, a collaborative network and growing database comprising metadata from 416 datasets across all realms (terrestrial, marine, freshwater and subterranean).Location: Worldwide, 12,343 sites, all ecosystem types.Time Period: 1991 to present.Major Taxa Studied: All soniferous taxa.Methods: We synthesise sampling coverage across spatial, temporal and ecological scales using metadata describing sampling locations, deployment schedules, focal taxa and audio recording parameters. We explore global trends in biological, anthropogenic and geophysical sounds based on 168 selected recordings from 12 ecosystems across all realms.Results: Terrestrial sampling is spatially denser (46 sites per million square kilometre—Mkm²) than aquatic sampling (0.3 and 1.8 sites/Mkm² in oceans and fresh water) with only two subterranean datasets. Although diel and lunar cycles are well sampled across realms, only marine datasets (55%) comprehensively sample all seasons. Across the 12 ecosystems selected for exploring global acoustic trends, biological sounds showed contrasting diel patterns across ecosystems, declined with distance from the Equator, and were negatively correlated with anthropogenic sounds.Main Conclusions: PAM can inform macroecological studies as well as global conservation and phenology syntheses, but representation can be improved by expanding terrestrial taxonomic scope, sampling coverage in the high seas and subterranean ecosystems, and spatio‐temporal replication in freshwater habitats. Overall, this worldwide PAM network holds promise to support cross‐realm biodiversity research and monitoring efforts.

Identification of ecologically significant units at different spatial scales is essential for management of biodiversity attributes. This case study illustrates a coupled methodological approach to delineate benthic habitats and associated assemblages at different spatial scales. Two complementary analyses were employed based on the occurrences of 99 epibenthic invertebrate species in Atlantic Canada, sampled during depth-stratified random trawl sets. To identify epibenthic assemblage types, isometric feature mapping and partitioning around medoids (ISOPAM) was used in combination with a joint species distribution model (JSDM), which also produced continuous distribution surfaces across the spatial domain. ISOPAM identified nine significantly spatially coherent assemblages (biotopes) at spatial scales of hundreds of meters to hundreds of kilometers, with associated diagnostic species. Those assemblages were closely matched by eight regions of common profile using the JSDM, indicating strong environmental influences on their distributions. These smaller-scale assemblages were grouped into three biophysical units. The results from the JSDM were validated with independent data showing good congruence. This indicates that the spatial units ascribed to identified assemblages are robust and suitable for marine spatial planning and monitoring.

Biodiversity changes and habitat shifts are two phenomena substantially reshaping marine life on our present and future planet. Although those phenomena are well recognized on the macrobial level, they currently do not receive similar attention on the microbial level. Generally, microbiome diversity and function, associated with and governing the health and fitness of their host organisms, are neglected in conservation efforts. This is especially problematic as previous research has highlighted that host‐associated microbes (microbiomes) may display distribution patterns that are not only correlated with host animal biogeographies but also with other factors such as prevailing environmental conditions. Here, marine spatial planning for socio‐ecological management of animal‐associated microbiomes is discussed, using deep‐sea sponge and coral‐associated microbiomes as an example of how to incorporate microbial diversity into conservation planning. We advocate for a holistic and integrative approach to marine spatial planning that incorporates the larger habitat, the host, the microbiome, as well as the socio‐economic and cultural perspective, throughout the whole decision‐making process. A general workflow containing the needed steps to establish microbiome‐integrated marine protected areas is presented, as well as the analytical steps and results underlying the implementation of the world's first microbiome‐considered marine conservation network on the Scotian Shelf off eastern Canada.

The deep-sea remains the biggest challenge to biodiversity exploration, and anthropogenic disturbances extend well into this realm, calling for urgent management strategies. One of the most diverse, productive, and vulnerable ecosystems in the deep sea are sponge grounds. Currently, environmental DNA (eDNA) metabarcoding is revolutionising the field of biodiversity monitoring, yet complex deep-sea benthic ecosystems remain challenging to assess even with these novel technologies. Here, we evaluate the effectiveness of whole-community metabarcoding to characterise metazoan diversity in sponge grounds across the North Atlantic by leveraging the natural eDNA sampling properties of deep-sea sponges themselves. We sampled 97 sponge tissues from four species across four North-Atlantic biogeographic regions in the deep sea and screened them using the universal COI barcode region. We recovered unprecedented levels of taxonomic diversity per unit effort, especially across the phyla Chordata, Cnidaria, Echinodermata and Porifera, with at least 406 metazoan species found in our study area. These assemblages identify strong spatial patterns in relation to both latitude and depth, and detect emblematic species currently employed as indicators for these vulnerable habitats. The remarkable performance of this approach in different species of sponges, in different biogeographic regions and across the whole animal kingdom, illustrates the vast potential of natural samplers as high-resolution biomonitoring solutions for highly diverse and vulnerable deep-sea ecosystems.

Aim: Seamounts are conspicuous geological features with an important ecological role and can be considered vulnerable marine ecosystems (VMEs). Since many deep‐sea regions remain largely unexplored, investigating the occurrence of VME taxa on seamounts is challenging. Our study aimed to predict the distribution of four cold‐water coral (CWC) taxa, indicators for VMEs, in a region where occurrence data are scarce.Location: Seamounts around the Cabo Verde archipelago (NW Africa).Methods: We used species presence–absence data obtained from remotely operated vehicle (ROV) footage collected during two research expeditions. Terrain variables calculated using a multiscale approach from a 100‐m‐resolution bathymetry grid, as well as physical oceanographical data from the VIKING20X model, at a native resolution of 1/20°, were used as environmental predictors. Two modelling techniques (generalized additive model and random forest) were employed and single‐model predictions were combined into a final weighted‐average ensemble model. Model performance was validated using different metrics through cross‐validation.Results: Terrain orientation, at broad scale, presented one of the highest relative variable contributions to the distribution models of all CWC taxa, suggesting that hydrodynamic–topographic interactions on the seamounts could benefit CWCs by maximizing food supply. However, changes at finer scales in terrain morphology and bottom salinity were important for driving differences in the distribution of specific CWCs. The ensemble model predicted the presence of VME taxa on all seamounts and consistently achieved the highest performance metrics, outperforming individual models. Nonetheless, model extrapolation and uncertainty, measured as the coefficient of variation, were high, particularly, in least surveyed areas across seamounts, highlighting the need to collect more data in future surveys.Main Conclusions: Our study shows how data‐poor areas may be assessed for the likelihood of VMEs and provides important information to guide future research in Cabo Verde, which is fundamental to advise ongoing conservation planning.

The urgency for remote, reliable, and scalable biodiversity monitoring amidst mounting human pressures on climate and ecosystems has sparked worldwide interest in Passive Acoustic Monitoring (PAM), but there has been no comprehensive overview of its coverage across realms. We present metadata from 358 datasets recorded since 1991 in and above land and water constituting the first global synthesis of sampling coverage across spatial, temporal, and ecological scales. We compiled summary statistics (sampling locations, deployment schedules, focal taxa, and recording parameters) and used eleven case studies to assess trends in biological, anthropogenic, and geophysical sounds. Terrestrial sampling is spatially denser (42 sites/M·km ² ) than aquatic sampling (0.2 and 1.3 sites/M·km ² in oceans and freshwater) with only one subterranean dataset. Although diel and lunar cycles are well-covered in all realms, only marine datasets (65%) comprehensively sample all seasons. Across realms, biological sounds show contrasting diel activity, while declining with distance from the equator and anthropogenic activity. PAM can thus inform phenology, macroecology, and conservation studies, but representation can be improved by widening terrestrial taxonomic breadth, expanding coverage in the high seas, and increasing spatio-temporal replication in freshwater habitats. Overall, PAM shows considerable promise to support global biodiversity monitoring efforts.

Aim: Protection of vulnerable marine ecosystems (VMEs) in the high seas has focussed on identifying concentrations of indicator species and prohibiting the operation of bottom‐contact fishing gears where those occur in significant concentrations. Most such species have planktonic larvae and depend on dispersal networks for inter‐generational persistence. Yet, connectivity amongst patches of VME has seldom been considered when spatial management measures are introduced. Here, the relative importance of individual patches for the maintenance of their connectivity networks is evaluated, and a prioritization scheme for management action is proposed. Effective conservation measures should maintain approximately natural network configurations whenever possible.Location: Grand Bank and Flemish Cap, Northwest Atlantic Ocean.Methods: 3‐D Lagrangian particle tracking was used to model larval dispersal connections between known patches of each of seven groups of benthic invertebrate taxa, previously recognized as indicators of VME. Connectivity networks were constructed and the effects of habitat loss simulated by systematic removal of whole patches, to determine the importance of each patch to connectivity within its respective network.Results: The various patches differed widely in their contributions to network connectivity. Each taxon group had both some patches that, if removed from the network, would result in a major decline in connectedness but also several which could be lost with negligible consequences for the remainder.Main Conclusions: While protecting each patch of VME has conservation value, the wide variation in connectedness shows that some patches are much more critical than others to the long‐term persistence of the taxa, providing a foundation for prioritization of conservation actions.