Biogeographic and seasonal differences in consumer pressure underlie strong predation in the tropics.

Biotic interactions play a critical role in shaping patterns of global biodiversity. While several macroecological studies provide evidence for stronger predation in tropical regions compared with higher latitudes, results are variable even within the tropics, and the drivers of this variability are not well understood. We conducted two complementary standardized experiments on communities of sessile marine invertebrate prey and their associated predators to test for spatial and seasonal differences in predation across the tropical Atlantic and Pacific coastlines of Panama. We further tested the prediction that higher predator diversity contributes to stronger impacts of predation, using both direct observations of predators and data from extensive reef surveys. Our results revealed substantially higher predation rates and stronger effects of predators on prey in the Pacific than in the Atlantic, demonstrating striking variation within tropical regions. While regional predator diversity was high in the Atlantic, functional diversity at local scales was markedly low. Peak predation strength in the Pacific occurred during the wet, non-upwelling season when ocean temperatures were warmer and predator communities were more functionally diverse. Our results highlight the importance of regional biotic and abiotic drivers that shape interaction strength and the maintenance of tropical communities, which are experiencing rapid environmental change.

Freshwater wetlands for flood control: How manipulating the hydroperiod affects plant and invertebrate communities.

Thoughtfully managed hydroperiods in natural and artificial wetlands could potentially provide a combination of desirable flood control services and high ecological functions. To explore how managed freshwater wetlands typical of the Houston, Texas area would respond to different hydrological regimes that might occur if wetlands were drained in anticipation of a heavy rain that did not materialize, we conducted a mesocosm experiment with six flooding depths and seven drought durations, followed by seven months of recovery. We found that the speed in which mesocosms dried out was a function of initial water depth, with mesocosms initially set with greater water depths (30 cm) taking ~ 38 days to dry out versus zero days for wetlands that were completely drained. Individual plant species (14 species planted; 8 species common at the end of the recovery period) were affected by drought length, flooding depth, or their interaction, although details of these responses varied among the species. The composition of the plant community at the end of the drought period was strongly affected by drought length, and the effect of the drought length treatment persisted through seven months of post-drought recovery, with the 80- and 160-day drought treatments diverging most strongly from shorter drought treatments. Above- and below-ground biomass of plants was not affected by the treatments, but above-ground dead biomass (litter) decreased with increasing drought length. Densities of mosquito larvae, snails and tadpoles were temporally variable, and were affected more during the treatment period and early in recovery than after a disturbance event late in recovery. Our results indicate that managed wetlands in southeast Texas would be quite resilient to dry periods of up to 40 days in duration, especially if water was not completely drained at the beginning of the drought. In addition, many species would persist in managed wetlands even with droughts of up to 160 days. This indicates considerable potential for managing the hydroperiods of artificial detention ponds by retaining water longer to increase ecological function, with little to no loss of flood control services, and for managing the hydroperiods of natural wetlands by draining them in advance of anticipated rains to increase flood control services, with little to no loss of ecological function.

Ocean warming and acidification adjust inter- and intra-specific variability in the functional trait expression of polar invertebrates.

Climate change is known to affect the distribution and composition of species, but concomitant alterations to functionally important aspects of behaviour and species-environment relations are poorly constrained. Here, we examine the ecosystem ramifications of changes in sediment-dwelling invertebrate bioturbation behaviour-a key process mediating nutrient cycling-associated with near-future environmental conditions (+ 1.5 °C, 550 ppm [pCO2]) for species from polar regions experiencing rapid rates of climate change. We find that responses to warming and acidification vary between species and lead to a reduction in intra-specific variability in behavioural trait expression that adjusts the magnitude and direction of nutrient concentrations. Our analyses also indicate that species behaviour is not predetermined, but can be dependent on local variations in environmental history that set population capacities for phenotypic plasticity. We provide evidence that certain, but subtle, aspects of inter- and intra-specific variation in behavioural trait expression, rather than the presence or proportional representation of species per se, is an important and under-appreciated determinant of benthic biogeochemical responses to climate change. Such changes in species behaviour may act as an early warning for impending ecological transitions associated with progressive climate forcing.

Changes in the composition of invertebrate assemblages from wave-exposed intertidal mussel stands along the Nova Scotia coast, Canada.

Rocky intertidal habitats occur worldwide and are mainly characterized by primary space holders such as seaweeds and sessile invertebrates. Some of these organisms are foundation species, as they can form structurally complex stands that host many small invertebrates. The abundance of primary space holders is known to vary along coastlines driven directly or indirectly by environmental variation. However, it is less clear if the invertebrate assemblages associated to a foundation species may remain relatively unchanged along coastlines, as similar stands of a foundation species can generate similar microclimates. We examined this question using abundance data for invertebrate species found in mussel stands of a similar structure in wave-exposed rocky habitats at mid-intertidal elevations along the Atlantic coast of Nova Scotia (Canada). While the most abundant invertebrate species were found at three locations spanning 315 km of coastline, species composition (a combined measure of species identity and their relative abundance) differed significantly among the locations. One of the species explaining the highest amount of variation among locations (a barnacle) exhibited potential signs of bottom-up regulation involving pelagic food supply, suggesting benthic-pelagic coupling. The abundance of the species that explained the highest amount of variation (an oligochaete) was positively related to the abundance of their predators (mites), further suggesting bottom-up forcing in these communities. Overall, we conclude that species assemblages associated to structurally similar stands of a foundation species can show clear changes in species composition at a regional scale.

How fishes and invertebrates impact coral resilience.

Increasingly intense and frequent ocean heatwaves are causing widespread coral mortality. These heatwaves are just one of the many stressors - among for instance ocean acidification, nutrient pollution and destructive fishing practices - that have caused widespread decline of coral reefs over the past century. This destruction of reefs threatens the remarkable biodiversity of organisms that depend upon coral reefs. However, recent research suggests that many of the fishes and invertebrates that inhabit coral reefs may play an underappreciated role in influencing the resistance and recovery of corals to stressors, especially those caused by global climate change such as ocean heatwaves. Unraveling the threads that link these coral inhabitants to the corals' response to stressors has the potential to weave a more comprehensive model of resilience that integrates the plight of coral reefs with the breathtaking diversity of life they host. Here, we aim to elucidate the critical roles that coral-associated fishes and invertebrates play in mediating coral resilience to environmental stressors. By integrating recent research findings, we aim to showcase how these often-overlooked organisms influence coral resilience in the face of climate change.

Early evolution of the ecdysozoan body plan.

Extant ecdysozoans (moulting animals) are represented by a great variety of soft-bodied or articulated organisms that may or may not have appendages. However, controversies remain about the vermiform nature (i.e. elongated and tubular) of their ancestral body plan. We describe here Beretella spinosa gen. et sp. nov. a tiny (maximal length 3 mm) ecdysozoan from the lowermost Cambrian, Yanjiahe Formation, South China, characterized by an unusual sack-like appearance, single opening, and spiny ornament. Beretella spinosa gen. et sp. nov has no equivalent among animals, except Saccorhytus coronarius, also from the basal Cambrian. Phylogenetic analyses resolve both fossil species as a sister group (Saccorhytida) to all known Ecdysozoa, thus suggesting that ancestral ecdysozoans may have been non-vermiform animals. Saccorhytids are likely to represent an early off-shot along the stem-line Ecdysozoa. Although it became extinct during the Cambrian, this animal lineage provides precious insight into the early evolution of Ecdysozoa and the nature of the earliest representatives of the group.

The abundant fraction of soil microbiomes regulates the rhizosphere function in crop wild progenitors.

The rhizosphere influence on the soil microbiome and function of crop wild progenitors (CWPs) remains virtually unknown, despite its relevance to develop microbiome-oriented tools in sustainable agriculture. Here, we quantified the rhizosphere influence-a comparison between rhizosphere and bulk soil samples-on bacterial, fungal, protists and invertebrate communities and on soil multifunctionality across nine CWPs at their sites of origin. Overall, rhizosphere influence was higher for abundant taxa across the four microbial groups and had a positive influence on rhizosphere soil organic C and nutrient contents compared to bulk soils. The rhizosphere influence on abundant soil microbiomes was more important for soil multifunctionality than rare taxa and environmental conditions. Our results are a starting point towards the use of CWPs for rhizosphere engineering in modern crops.

Neighbourhood benthic configuration reveals hidden co-occurrence social diversity.

Ecological interactions among benthic communities are crucial for shaping marine ecosystems. Understanding these interactions is essential for predicting how ecosystems will respond to environmental changes, invasive species, and conservation management. However, determining the prevalence of species interactions at the community scale is challenging. To overcome this challenge, we employ tools from social network analysis, specifically exponential random graph modelling (ERGM). Our approach explores the relationships among animal and plant organisms within their neighbourhoods. Inspired by companion planting in agriculture, we use spatiotemporal co-occurrence as a measure of mixed species interaction. In other words, the variety of community interactions based on co-occurrence defines what we call 'co-occurrence social diversity'. Our objective is to use ERGM to quantify the proportion of interactions at both the simple paired level and the more complex triangle level, enabling us to measure and compare co-occurrence social diversity. Applying our approach to the Spanish coastal zone across eight sites, five depths, and sunlit/shaded aspects, we discover that 80% of sessile communities, consisting of over a hundred species, exhibit co-occurrence social diversity, with 5% of species consistently forming associations with other species. These organism-level interactions probably have a significant impact on the overall character of the site. This article is part of the theme issue 'Connected interactions: enriching food web research by spatial and social interactions'.

Potential drivers of changing ecological conditions in English and Welsh rivers since 1990.

River invertebrate communities across Europe have been changing in response to variations in water quality over recent decades, but the underlying drivers are difficult to identify because of the complex stressors and environmental heterogeneity involved. Here, using data from ∼4000 locations across England and Wales, collected over 29 years, we use three approaches to help resolve the drivers of spatiotemporal variation in the face of this complexity: i) mapping changes in invertebrate richness and community composition; ii) structural equation modelling (SEM) to distinguish land cover, water quality and climatic influences; and iii) geographically weighted regression (GWR) to identify how the apparent relationships between invertebrate communities and abiotic variables change across the area. Mapping confirmed widespread increases in richness and the proportion of pollution-sensitive taxa across much of England and Wales. It also revealed regions where pollution-sensitive taxa or overall richness declined, the former primarily in the uplands. SEMs confirmed strong increases in average biochemical oxygen demand and nutrient concentrations related to urban and agricultural land cover, but only a minority of land cover's effect upon invertebrate communities was explained by average water chemistry, highlighting potential factors such as episodic extremes or emerging contaminants. GWR identified strong geographical variation in estimated relationships between macroinvertebrate communities and environmental variables, with evidence that the estimated negative impacts of nutrients and water temperature were increasing through time. Overall the results are consistent with widespread biological recovery of Britain's rivers from past gross organic pollution, whilst highlighting declines in some of the most diverse and least impacted streams. Modelling points to a complex and changing set of drivers, highlighting the multifaceted impacts of catchment land cover and the evolving role of different stressors, with the relationship to gross organic pollution weakening, whilst estimated nutrient and warming effects strengthened.

Combined effects of herbicides and insecticides reduce biomass of sensitive aquatic invertebrates.

The structure and biomass of aquatic invertebrate communities play a crucial role in the matter dynamics of streams. However, biomass is rarely quantified in ecological assessments of streams, and little is known about the environmental and anthropogenic factors that influence it. In this study, we aimed to identify environmental factors that are associated with invertebrate structure and biomass through a monitoring of 25 streams across Germany. We identified invertebrates, assigned them to taxonomic and trait-based groups, and quantified biomass using image-based analysis. We found that insecticide pressure generally reduced the abundance of insecticide-vulnerable populations (R2 = 0.43 applying SPEARpesticides indicator), but not invertebrate biomass. In contrast, herbicide pressure reduced the biomass of several biomass aggregations. Especially, insecticide-sensitive populations, that were directly (algae feeder, R2 = 0.39) or indirectly (predators, R2 = 0.29) dependent on algae, were affected. This indicated a combined effect of possible food shortage due to herbicides and direct insecticide pressure. Specifically, all streams with increased herbicide pressure showed a reduced overall biomass share of Trichoptera from 43 % to 3 % and those of Ephemeroptera from 20 % to 3 % compared to streams grouped by low herbicide pressure. In contrast, insecticide-insensitive Gastropoda increased from 10 % to 45 %, and non-vulnerable leaf-shredding Crustacea increased from 10 % to 22 %. In summary, our results indicate that at the community level, the direct effects of insecticides and the indirect, food-mediated effects of herbicides exert a combined effect on the biomass of sensitive insect groups, thus disrupting food chains at ecosystem level.

Environmental gradients mediate dispersal evolution during biological invasions.

Rapid evolution of increased dispersal at the edge of a range expansion can accelerate invasions. However, populations expanding across environmental gradients often face challenging environments that reduce fitness of dispersing individuals. We used an eco-evolutionary model to explore how environmental gradients influence dispersal evolution and, in turn, modulate the speed and predictability of invasion. Environmental gradients opposed evolution of increased dispersal during invasion, even leading to evolution of reduced dispersal along steeper gradients. Counterintuitively, reduced dispersal could allow for faster expansion by minimizing maladaptive gene flow and facilitating adaptation. While dispersal evolution across homogenous landscapes increased both the mean and variance of expansion speed, these increases were greatly dampened by environmental gradients. We illustrate our model's potential application to prediction and management of invasions by parameterizing it with data from a recent invertebrate range expansion. Overall, we find that environmental gradients strongly modulate the effect of dispersal evolution on invasion trajectories.

Synaptic Mechanisms of Ethanol Tolerance and Neuroplasticity: Insights from Invertebrate Models.

Alcohol tolerance is a neuroadaptive response that leads to a reduction in the effects of alcohol caused by previous exposure. Tolerance plays a critical role in the development of alcohol use disorder (AUD) because it leads to the escalation of drinking and dependence. Understanding the molecular mechanisms underlying alcohol tolerance is therefore important for the development of effective therapeutics and for understanding addiction in general. This review explores the molecular basis of alcohol tolerance in invertebrate models, Drosophila and C. elegans, focusing on synaptic transmission. Both organisms exhibit biphasic responses to ethanol and develop tolerance similar to that of mammals. Furthermore, the availability of several genetic tools makes them a great candidate to study the molecular basis of ethanol response. Studies in invertebrate models show that tolerance involves conserved changes in the neurotransmitter systems, ion channels, and synaptic proteins. These neuroadaptive changes lead to a change in neuronal excitability, most likely to compensate for the enhanced inhibition by ethanol.

Air pollution disproportionately impairs beneficial invertebrates: a meta-analysis.

Air pollution has the potential to disrupt ecologically- and economically-beneficial services provided by invertebrates, including pollination and natural pest regulation. To effectively predict and mitigate this disruption requires an understanding of how the impacts of air pollution vary between invertebrate groups. Here we conduct a global meta-analysis of 120 publications comparing the performance of different invertebrate functional groups in unpolluted and polluted atmospheres. We focus on the pollutants ozone, nitrogen oxides, sulfur dioxide and particulate matter. We show that beneficial invertebrate performance is reduced by air pollution, whereas the performance of plant pest invertebrates is not significantly affected. Ozone pollution has the most detrimental impacts, and these occur at concentrations below national and international air quality standards. Changes in invertebrate performance are not dependent on air pollutant concentrations, indicating that even low levels of pollution are damaging. Predicted increases in tropospheric ozone could result in unintended consequences to global invertebrate populations and their valuable ecological services.

Declining glacier cover drives changes in aquatic macroinvertebrate biodiversity in the Cordillera Blanca, Perú.

Ongoing climate change threatens the biodiversity of glacier-fed river ecosystems worldwide through shifts in water availability and timing, temperature, chemistry, and channel stability. However, tropical glacier-fed rivers have received little attention compared to those in temperate and Arctic biomes, despite their unique biodiversity potentially responding differently due to additional stress from higher altitude locations thus lower oxygen availability, diurnal freeze-thaw cycles, and annual monsoon rainfall disturbances. However, tropical glacier-fed rivers have received little attention compared to those in temperate and Arctic biomes, despite their unique biodiversity potentially responding differently due to additional stress from higher altitude locations thus lower oxygen availability, diurnal freeze-thaw cycles, and annual monsoon rainfall disturbances. This study quantified aquatic biodiversity responses to decreasing glacier cover in the Cordillera Blanca range of the Peruvian Andes. Ten rivers were studied along a gradient of decreasing glacier cover in the Parón, Huaytapallana, and Llanganuco basins, with a specific focus on macroinvertebrates and physicochemical parameters in both the dry and wet seasons. We found higher temperatures, more stable and lower turbidity rivers as glacier cover decreased, which were related significantly to higher local diversity and lower ß-diversity. Analysis of similarity revealed significant differences in the macroinvertebrate community among rivers with high, medium, or low glacier cover, illustrating turnover from specialists to generalists as glacial influence decreased. Redundancy analysis demonstrated that there were more species found to prefer stable beds and water temperatures in medium and low glacier cover in a catchment rivers. However, certain taxa in groups such as Paraheptagyia, Orthocladiinae, Anomalocosmoecus, and Limonia may be adapted to high glacial influence habitats and at risk of glacier retreat. Although species composition was different to other biomes, the Cordillera Blanca rivers showed similar benthic macroinvertebrate biodiversity responses to glacier retreat, supporting the hypothesis that climate change will have predictable effects on aquatic biodiversity in mountain ranges worldwide.

Tracking the hologenome dynamics in aquatic invertebrates by the holo-2bRAD approach.

The "hologenome" concept is an increasingly popular way of thinking about microbiome-host for marine organisms. However, it is challenging to track hologenome dynamics because of the large amount of material, with tracking itself usually resulting in damage or death of the research object. Here we show the simple and efficient holo-2bRAD approach for the tracking of hologenome dynamics in marine invertebrates (i.e., scallop and shrimp) from one holo-2bRAD library. The stable performance of our approach was shown with high genotyping accuracy of 99.91% and a high correlation of r > 0.99 for the species-level profiling of microorganisms. To explore the host-microbe association underlying mass mortality events of bivalve larvae, core microbial species changed with the stages were found, and two potentially associated host SNPs were identified. Overall, our research provides a powerful tool with various advantages (e.g., cost-effective, simple, and applicable for challenging samples) in genetic, ecological, and evolutionary studies.

An ecohydrological approach to assess water provisioning and supporting ecosystem services in the Budhabalanga River Basin, India.

Rivers are vital and complex natural systems that provide a wide range of ecosystem services. This study presents a methodology for assessing the riverine provisioning and supporting ecosystem services, whose applicability has been demonstrated over the Budhabalanga River Basin of India. The Soil and Water Assessment Tool (SWAT) is used to generate streamflow time series at various ungauged sites, and then the streamflow is characterized for the evaluation of provisioning services. Further, the diversity and abundance of macroinvertebrates, along with the Lotic-invertebrate Index for Flow Evaluation (LIFE), is used to study the riverine supporting ecosystem services. The streams show intermittent behavior and strong seasonality for low flows, which limits the water availability, particularly during pre-monsoon season. The Baseflow Index (BFI) is greater than 0.6, indicating that groundwater contributes more than 60% of the total streamflow. Interestingly, despite the high BFI, the streams did not conform to the prevailing opinion that a greater baseflow contribution results in a later commencement of the low-flow period in the hydrological year. Furthermore, the study depicts significant variations in the diversity and abundance of the macroinvertebrates across the various sampling sites. However, the LIFE score across the sites remained consistent within a narrow range, i.e., 8 to 9, suggesting a steady supply of supporting ecosystem services. The results of the study can help the policymakers towards an informed decision making and the simplistic methodology proposed in this study can be replicated in other river basins for identifying vulnerable watersheds and prioritizing management actions.

Transcriptome sequencing of seven deep marine invertebrates.

We present 4k video and whole transcriptome data for seven deep-sea invertebrate animals collected in the Eastern Pacific Ocean during a research expedition onboard the Schmidt Ocean Institute's R/V Falkor in August of 2021. The animals include one jellyfish (Atolla sp.), three siphonophores (Apolemia sp., Praya sp., and Halistemma sp.), one larvacean (Bathochordaeus mcnutti), one tunicate (Pyrosomatidae sp.), and one ctenophore (Lampocteis sp.). Four of the animals were sequenced with long-read RNA sequencing technology, such that the reads themselves define a reference assembly for those animals. The larvacean tissues were successfully preserved in situ and has paired long-read reference data and short read quantitative transcriptomic data for within-specimen analyses of gene expression. Additionally, for three animals we provide quantitative image data, and a 3D model for one siphonophore. The paired image and transcriptomic data can be used for species identification, species description, and reference genetic data for these deep-sea animals.

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As regulators of the surface land processes, soil fauna communities are the vital foundations for healthy terrestrial ecosystems. Soil fauna have been studied in China for more than 70 years. Great progresses have been achieved in exploring soil fauna species composition and geographical distribution patterns. Soil fauna eco-geography, as a bridge between soil fauna geographic patterns and ecosystem services, has a new development opportunity with the deep recognition of soil fauna ecological functions. Soil fauna eco-geography research could be partitioned into four dimensions including the spatio-temporal patterns of: 1) the apparent characteristics of soil fauna community, such as species composition, richness and abundance; 2) the intrinsic characteristics of soil fauna community, such as dietary and habits; 3) soil fauna-related biotic and abiotic interactions especially those indicating drivers of soil fauna community structure or shaping the roles of soil fauna in ecosystems; and 4) soil fauna-related or -regulated key ecological processes. Current studies focus solely on soil fauna themselves and their geographical distributions. To link soil fauna geography more closely with ecosystem services, we suggested that: 1) converting the pure biogeography studies to those of revealing the spatio-temporal patterns of the soil fauna-related or regulated key relationships and ecological processes;2) expanding the temporal and spatial scales in soil fauna geographical research;3) exploring the integrated analysis approach for soil fauna-related data with multi-scales, multi-factors, and multi-processes;and 4) establishing standard reference systems for soil fauna eco-geographical researches. Hence, the change patterns of ecological niche of soil fauna communities could be illustrated, and precision mani-pulations of soil fauna communities and their ecological functions would become implementable, which finally contributes to ecosystem health and human well-being.

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To understand the macrozoobenthic community composition and spatial-temporal distribution characteristics of macrobenthos in the waters of Miaodao Archipelago, Yantai, Shandong and its response to habitat changes, we conducted surveys of macrobenthos and environmental elements in the waters of Miaodao Islands in May (spring), August (summer), and October (autumn) in 2022. Results showed that a total of 127 macrozoobenthic species were recorded, with Mollusca and Annelida (Polychaeta) as the dominant taxa, consisting of 47 and 45 species, respectively. The key dominant species included Sternaspis chinensis, Glycinde bonhourei, Moerella hilaris, and Amphioplus (Lymanella) japonicus. The average annual density and biomass of macrozoobenthos were 190 ind·m-2 and 28.69 g·m-2, respectively. There was no significant seasonal differences in density and biomass. The Shannon diversity index (H), evenness index (J), and richness index (D) averaged 3.10, 0.90, and 2.40, respectively. Cluster analysis results showed low similarity coefficients of community among the three seasons, suggesting a distinct distribution pattern. Factors such as bottom seawater temperature, chlorophyll a, nutrient, sediment grain size, and organic matter content could significantly influence the structure and diversity of macrozoobenthic community. Compared with historical research data, the Changdao National Wetland Nature Reserve and the implementation of enclosure aquaculture have led to notable changes in the dominant species of macrobenthos. Specifically, there was a noticeable decline in both density and H, and an increase in biomass and J. Additionally, body size of benthic fauna was transitioning from small to big.

Dissimilarity of megabenthic community structure between deep-water seamounts with cobalt-rich crusts: Case study in the northwestern Pacific Ocean.

As anthropogenic disturbance on deep-sea seamount ecosystems grows, there is an urgent need for a better understanding of the biodiversity and community structure in benthic ecosystems, which can vary at local and regional scales. A survey of the benthic megafauna on two adjacent deep-water seamounts in the northwestern Pacific Ocean was conducted, which are covered by cobalt-rich crusts, to assess the biodiversity patterns and dissimilarity of assemblage composition. Based on a multidisciplinary dataset generated from video recordings, multibeam bathymetry data, and near-bottom currents, environmental and spatial factors impacting the megabenthic communities were explored. Results showed that these two deep-water seamounts were dominated by hexactinellids, crinoids, and octocorals. The seamounts were able to support diverse and moderately abundant megafauna, with a total of 6436 individuals classified into 94 morphospecies. The survey covered a distance of 52.2 km across a depth range of 1421-3335 m, revealing multiple distinct megabenthic assemblages. The megabenthic communities of the two deep-water seamounts, with comparable environmental conditions, exhibited similarities in overall density, richness, and faunal lists, while dissimilarities in the relative abundance of taxa and assemblage composition. No gradual depth-related change in terms of abundance, richness, or species turnover was observed across the two seamounts, despite the statistical significance of depth in structuring the overall communities. The spatial distribution of megabenthic communities displayed a discontinuous and patchy pattern throughout the two deep-water seamounts. This patchiness was driven by the interactive effects of multiple environmental factors. Near-bottom currents and microhabitat features were the primary drivers influencing their dissimilarities in megabenthic community structure. This case study on the megabenthic community structure of two adjacent seamounts with cobalt-rich crusts can serve as an environmental baseline, providing a reference status for the conservation and management of seamount ecosystems, particularly valuable for areas being considered for deep-sea mining.