The early Palaeozoic saw a dramatic diversification of shelly epibenthic metazoans adapted to suspension and filter feeding, but the extent to which these radiations affected the evolution of non-biomineralized suspension-feeding taxa is uncertain because these organisms are not typically well represented in the fossil record. Luolishaniids are a highly derived and disparate clade of (typically) armoured lobopodians, widely interpreted as suspension feeders based on the presence of five or six anterior pairs of setulose appendages. Luolishaniids are globally widespread and represent the only Cambrian non-biomineralized free-living epibenthic bilaterians suggested to have a suspension-feeding mode of life, but their proposed ecology relies solely on a qualitative interpretation of their functional morphology. Here we test the hypothesis that the setulose appendages of luolishaniids were adapted for a suspension-feeding function. Quantitative morphological comparisons reveal a positive and statistically significant relationship between body length and the mesh spacing of the setulose anterior limbs of luolishaniids. Standardized comparisons indicate that the body size disparity between luolishaniids (predators) and Cambrian mesoplankton (prey) is consistent with patterns observed in modern suspension-feeding organisms. We provide quantitative evidence for suspension feeding in luolishaniids, which represents the first statistically supported example of modern-like predator-prey scaling patterns observed in Cambrian soft-bodied metazoans. Despite the uncanny appearance of luolishaniids, and Cambrian organisms more broadly, our results suggest their adaptations and mode of life feature ecological attributes shared with modern marine invertebrates.

Microplastics are pervasive in both freshwater and marine waters, posing potential hazards to a wide range of species. Evaluating environmental microplastic pollution is crucial for ecological risk assessment. However, current monitoring methods, such as sampling nets, are inefficient for quantifying small microplastics (< 25 µm) and non-buoyant particles, leading to potential underestimation of pollution levels. Biomonitors, like suspension-feeding organisms, can serve as complementary tools. This study takes a first step in evaluating bivalves as biomonitors by assessing whether microplastic uptake in their tissues correlates with environmental concentrations in both marine and freshwater conditions. Two mussel models, the marine Mytilus galloprovincialis and the freshwater Dreissena spp., were exposed to varying concentrations of microplastics (from 0 to 2000 MPs.L-1) over 48 h. Both marine and freshwater mussels followed a linear model for MP uptake. However, an exponential model appeared more suitable for M. galloprovincialis whereas a Gaussian model better described the uptake pattern in Dreissena spp., suggesting the presence of a threshold in MP capture for the latter species. Microplastics primarily accumulated in the digestive gland compared to other tissues (i.e., byssus, gills, mantle, and others). After 48 h of depuration, marine mussels exhibited a high microplastic depuration rate (from 88 to 97%), while freshwater mussels showed moderate depuration ability (from 0 to 71%). These results support M. galloprovincialis as an effective biomonitor for marine microplastic pollution. In freshwaters, the non-linear accumulation of microplastics by Dreissena spp. limits their suitability for precise pollution assessment, but may help set pollution alert levels based on MP content and sub-lethal effects. This study contributes to addressing the challenge of accurate MP quantification in aquatic environments by highlighting the potential of bioindicators in complementing traditional methods.

Seamounts are biodiversity hotspots that face increasing threats from anthropogenic activities. Seamounts host diverse sessile suspension-feeding organisms such as sponges and anthozoans, which are crucial for seamount ecosystems as they construct three-dimensional habitats utilized by numerous other animals. Therefore, accurate identification of seamount fauna, in particular of sessile suspension-feeding organisms, is of paramount importance for robust conservation efforts. This study focused on Zoantharia, a sessile anthozoan group, and specifically the family Parazoanthidae, known for associations with many different host taxa, prominently including octocorals and sponges. We collected Parazoanthidae specimens from northwestern Pacific seamounts and formally describe a new species, Vitrumanthusflosculus Kise & Reimer, sp. nov., based on morphological and molecular analyses. We also report the complete mitochondrial genomes of this new species and the related species Churabanakuroshioae. Our results reconfirm the phylogenetic positions of these two species within Parazoanthidae, while demonstrating much remains to be learned about the benthic diversity of northwestern Pacific seamounts.

Trace fossil association related to the Upper Miocene transgression cycle in the Lower Chelif Basin, NW Algeria

Volcanic ash in the water column: Cellular, physiological and anatomical implications for the gastropod suspension-feeder Crepipatella peruviana (Lamarck, 1822)

The arrival of a new invasive alga, Rugulopteryx okamurae, in the Strait of Gibraltar (SoG) in 2015 marked an unprecedented milestone in the North African and, later, in the European marine ecosystems. Nowadays, it is colonising vast infralittoral areas and significantly modifying some habitats and associated communities of the southern Iberian Peninsula. In recent expeditions, a high amount of free drifted thalli of this alga has been detected in different circalittoral and bathyal habitats of the northern SoG and the Alboran Sea. The present study combines quantitative data of this alga obtained with the use of a remotely operated vehicle (ROV) and a bottom otter trawl. The coverage–entanglement level of the drifted thalli on circalittoral and bathyal benthic invertebrates (e.g., not covering, covering only the basal part, covering one-third of the invertebrate, etc.) was also annotated from picture frames taken in locations with abundant drifted thalli. In underwater images, drifted thalli were mainly detected in circalittoral and bathyal bottoms of the northern SoG and the north-western Alboran Sea, between 50 to ca. 450 m depth. Nevertheless, abundant drifted thalli were also detected in bottom otter trawl samples from circalittoral bottoms of the north-central and north-eastern Alboran Sea. Small benthic organisms (e.g., encrusting sponges, hydrozoans, etc.) generally displayed low coverage–entanglement levels of drifted thalli. Nevertheless, large sessile and colonial benthic organisms with a complex three-dimensional morphology (e.g., gorgonians, colonial scleractinians) reached high levels of R. okamurae thalli entangled in different parts of their colonies. The drifted R. okamurae thalli entangled in these colonial suspension feeding organisms may hinder their feeding capability in the long term, resulting in habitat deterioration in the near future.

Estuaries worldwide are grappling with deteriorating water quality and benthic conditions that coincide with the rising detection of pathogenic and potentially pathogenic microbes (PPM). Both indigenous PPM and those that enter estuaries through urban and agricultural runoff are funneled through suspension-feeding organisms and deposited onto the benthos, where they can be moved through food webs. This study explored PPM communities in the Indian River Lagoon system, a biodiverse but urbanized estuary in east central Florida (USA). PPM were surveyed in estuary water, at stormwater outfalls, and in biodeposits of a key suspension feeder, the eastern oyster Crassostrea virginica. A total of 52 microbial exact sequence variants, with per-sample relative abundances up to 61.4%, were identified as PPM. The biodeposits contained relatively more abundant and diverse PPM than the water samples. PPM community composition also differed between seasons and between biodeposits and water. The community differences were driven primarily by Vibrio and Pseudoalteromonas spp. This investigation provides evidence that, through biodeposition, oyster reefs in the IRL estuary are a reservoir for PPM, and it documents some taxa of concern that should be conclusively identified and investigated for their pathogenicity and potential to pervade food webs and fisheries.

Microplastics (≤ 10 μm) bioaccumulation in marine sponges along the Moroccan Mediterranean coast: Insights into species-specific distribution and potential bioindication

ABSTRACT Microplastic (MP) particles (<5000 µm) pose a risk to many marine organisms. Globally, sponges are important suspension-feeding organisms that may be particularly vulnerable to MPs since many of these particles fall within their food size range. However, there has been little research on spatial variation in MP abundance in sponges. Here we examined MP abundance and spatial variation in sponges from Aotearoa New Zealand (NZ). We aimed to confirm the presence of potential microplastics (PMPs) in samples from 45 sponge samples across six species and three sites in the Wellington Harbour. Samples were digested with bleach, filtered, and analysed using fluorescent microscopy to quantify and measure PMPs. PMPs were present in every sponge sample with abundances between 207 ± 131 and 1893 ± 396 PMP particles g-1 (dry sponge weight). There were significant differences in PMP abundance between sites and between some species, but most of the variation was explained by site (40–53% vs. 4–24% of the variance). Our results suggest that PMP abundance in sponges is mainly explained by spatial variation in microplastic abundance rather than species identity.

Abstract Recent work has focused on erecting new Seilacherian ichnofacies for depositional environments subject to recurring temporal and spatial variations in physico-chemical stress. In marine deltaic settings, these correspond to the Phycosiphon Ichnofacies for mudstone-dominated prodeltaic deposits and the Rosselia Ichnofacies for sandstone-dominated delta-front successions. The archetypal expressions of these ichnofacies, however, are founded on mixed process (wave- and river-influenced) systems, because the juxtaposition of ambient marine conditions during periods of prolonged wave energy with rapid deposition and physico-chemically stressed conditions during heightened fluvial discharge best expresses the deltaic signal. As deltaic settings shift towards end-member processes (e.g. river domination, wave domination and tide domination), or towards mixed-process conditions other than river and wave influence, the resulting ichnological suites and bioturbation fabrics depart from the recently published archetypes. Using selected studies of marine deltaic deposits, predictable departures from the archetypes can be recognized on the basis of these changing processes and their associated physico-chemical stresses. River-dominated delta deposits and tide-dominated delta successions display the greatest deviation from the published archetypes. River-dominated examples show elevated deposition rates, periods of salinity reduction, slumping and dewatering, elevated water turbidity, flood-induced sediment gravity flows and hypopycnal-generated fluid mud. As a result, river-dominated successions are largely devoid of bioturbation. Evidence of marine conditions is commonly restricted to isolated occurrences of dwelling structures such as Arenicolites , Ophiomorpha or Rosselia in sandstone, and Chondrites , Phycosiphon or Zoophycos in mudstone beds, particularly in prodeltaic intervals. Tide-dominated deltaic successions are markedly heterolithic and typified by highly mobile substrates manifested by incrementally migrating asymmetric bedforms and abundant fluid mud. Such settings are also prone to marked changes in salinity and shifts in the position of the turbidity maximum zone. Successions typically show low intensities of bioturbation and sporadically distributed burrows, as well as deposit-feeding structures, deeply penetrating dwelling structures or fugichnia. Many trace fossil suites consist entirely of facies-crossing elements, making assignment to an ichnofacies impossible. Storm flood-dominated deltaic successions are characterized by tempestites that are typically interstratified with river flood-induced sediment-gravity flow deposits and/or mantled by largely unburrowed mudstone drapes derived from hypopycnal plumes associated with river floods. Where these storm flood cycles are interstratified with ambient fairweather beds, assignment to the archetypal deltaic ichnofacies is straightforward. However, as storm beds become increasingly erosionally amalgamated, the preservation potential of the fairweather beds is reduced and the resulting trace fossil suites are biased towards those recording opportunistic colonization of the event beds. The presence of mudstone layers with low bioturbation intensity (BI) containing small numbers of ichnogenera positively correlated with marine conditions (e.g. Chondrites , Phycosiphon and/or Zoophycos ) may be the only evidence that the suites should be assigned to one of the deltaic ichnofacies. Wave-dominated deltas lacking significant storm influence are typically challenging to differentiate from their archetypal strandplain shoreface counterparts and, correspondingly, the resulting trace fossil suites are broadly comparable to the archetypal Cruziana and Skolithos ichnofacies. Most of the preserved record of wave-dominated delta successions is related to fairweather ambient conditions, and so facies typically show high BI values and uniformly distributed bioturbation. Key to recognizing that the suites should be assigned to one of the deltaic ichnofacies is the presence of rare river-generated mudstone and sandstone beds that display evidence of physico-chemical stress and/or the paucity of domichnia typical of suspension-feeding organisms. In most delta types, the prodeltaic facies are most readily discerned to contain trace fossil suites of the Phycosiphon Ichnofacies, owing to the higher preservation potential of all depositional processes, including marine fairweather beds, river-supplied hyperpycnites and other sediment gravity flow deposits, tempestites and fluid mud derived from river flood-related hypopycnal plumes. Assignment of trace fossil suites to the Rosselia Ichnofacies requires some record of the fairweather conditions, which are generally diminished in river-, tide- and storm-dominated successions. The dominance of structures positively correlated to deposit-feeding ethologies at the expense of those attributed to suspension-feeding strategies may point to elevated water turbidity and assignment of the suite to the Rosselia Ichnofacies. However, in many cases, the ichnological suites of delta fronts are so depauperate that assignment to an ichnofacies is problematic and should be avoided.

Offshore windfarms (OWFs) offer part of the solution for the energy transition which is urgently needed to mitigate effects of climate change. Marine life has rapidly exploited the new habitat offered by windfarm structures, resulting in increased opportunities for filter- and suspension feeding organisms. In this study, we investigated the effects of organic matter (OM) deposition in the form of fecal pellets expelled by filtering epifauna in OWFs, on mineralization processes in the sediment. OM deposition fluxes produced in a 3D hydrodynamic model of the Southern Bight of the North Sea were used as input in a model of early diagenesis. Two scenarios of OWF development in the Belgian Part of the North Sea (BPNS) and its surrounding waters were calculated and compared to a no-OWF baseline simulation. The first including constructed OWFs as of 2021, the second containing additional planned OWFs by 2026. Our results show increased total mineralization rates within OWFs (27–30%) in correspondence with increased deposition of reactive organic carbon (OC) encapsulated in the OM. This leads to a buildup of OC in the upper sediment layers (increase by ∼10%) and an increase of anoxic mineralization processes. Similarly, denitrification rates within the OWFs increased, depending on the scenario, by 2–3%. Effects were not limited to the OWF itself: clear changes were noticed in sediments outside of the OWFs, which were mostly opposite to the “within-OWF” effects. This contrast generated relatively small changes when averaging values over the full modeling domain, however, certain changes, such as for example the increased storage of OC in sediments, may be of significant value for national / regional carbon management inventories. Our results add to expectations of ecosystem-wide effects of windfarms in the marine environments, which need to be researched further given the rapid rate of expansion of OWFs.

The Early Paleozoic oceans were generally characterized by short trophic chains and simple ecological tiering dominated by suspension-feeding organisms. Howev-er, the Great Ordovician Biodiversification Event (GOBE) was responsible for the complexification of food webs, increasing depth and diversity of substrate ecospace utilization and increasing benthic competition for resources near the water-sub-strate interface. Daedalus is an enigmatic trace fossil that precedes this period of nearshore innovation and its disappearance is probably related to the escalation in tiering complexity, especially among benthic surficial feeders, that may have cut access to their main food sources. Daedalus producers were responsible for the oc-cupation of some of the earliest deep substrate tiers, probably feeding from particu-late organics and meiofauna using complex architectures for resource exploitation. They were responsible for characteristic ichnofabrics that can be found, especially in Lower-to-Middle Ordovician sandstones, in the “Armorican Quartzite” and similar nearshore facies around Gondwana. Villuercas-Ibores-Jara and Naturtejo UNESCO Global Geopark show several geosites where the best-preserved forms of Daedalus can be found and where its crowded ichnofabrics can be followed in large-scale exposures. Indeed, these are mega-ichnosites of international paleontological relevance for understanding behavior and ecospace utilization of a characteristic trace fossil during the GOBE. This paleoecological significance meant that Daedalus became a symbol for a cross-border Interreg Project that connects the two UNE-SCO geoparks. The Armorican Quartzite Route is an 800 km-long road following the main geological structures and promoting sustainable tourism attractions along the way. The Bridge over the Armorican Quartzite has the goal of fostering sustainable development through common scientific and education tools, raising awareness of the GOBE as one of the most important events of biodiversification in the Earth history and a key element of the geological heritage of both UNESCO Geoparks.

Plankton net mesh size influences the resultant diversity and abundance estimates of copepods in tropical oligotrophic ecosystems

Deposit-feeding and suspension-feeding benthos in Buzzards Bay, Massachusetts, show marked spatial separation; suspension feeders are largely confined to sandy or firm mud bottoms while deposit feeders attain high densities on soft muddy substrata. Food source and bottom stability have been investigated as potential factors effecting this trophic-group separation. Between October 4, 1967 and August 22, 1969, observations were made at 11 stations in Buzzards Bay, Massachusetts, along two widely separated transects over bottoms ranging in texture from silt to fine and medium sand. Water depths at these stations ranged from 3 m to 20 m. Scuba divers made many of the field observations and collected most of the samples. This study included sampling of benthic macrofauna, taking bottom photographs, analyzing sedimentary structures, texture, organic content and water content of the sediments, and measuring both water currents and suspended sediment above the bottom. Laboratory experiments were also carried out to determine differential resuspension between burrowed and unburrowed muds. Intensive reworking of the upper few centimeters of a mud bottom by deposit feeders produces a fluid fecal-rich surface that is easily resuspended by low-velocity tidal currents. We suggest that the physical instability of this fecal surface tends to: (i) clog the filtering structures of suspension-feeding organisms, (ii) bury newly settled larvae or discourage the settling of suspension-feeding larvae, and (iii) prevent sessile epifauna from attaching to an unstable mud bottom. Thus suspension feeders are unable to successfully populate all areas of the bottom where a suspended food source is available, especially in areas where mud bottoms are intensively reworked by deposit feeders. Modification of the benthic environment by deposit feeders, resulting in the exclusion of many suspension feeders and sessile epifauna, is an example of trophic group amensalism. This biotic relationship appears to be important in shaping trophic-group distributions in embayments and basins on continental shelves.

The Alboran Sea is widely recognized to host numerous cold-water coral ecosystems, including the East Melilla Coral Province. Yet, their development through time and response to climatic variability has still to be fully understood. Based on a combined investigation of benthic foraminiferal assemblages, foraminiferal stable isotope compositions, grain size analysis, sediment geochemistry, and macrofaunal quantification, this study identifies key events and processes having governed cold-water coral development at the East Melilla Coral Province between Greenland Stadial 2.1 and the Early Holocene. The transition from Greenland Stadial 2.1 to Greenland Interstadial 1 is associated to a decline of bryozoan communities and their replacement by cold-water corals, together with changes in benthic foraminiferal assemblages and a decrease in the sediment mean grain size. These results suggest that a rapid decrease in bottom currents and the establishment of dysoxic and mesotrophic conditions at the seafloor, possibly associated to enhanced fluvial input, resulted in the decline of bryozoans as the dominant suspension feeding organisms and their replacement by a thriving cold-water coral community. This transition from a bryozoan to a coral dominated environment is concomitant with the beginning of the African Humid Period, confirming that increasing fluvial input could have been a main factor triggering the establishment of cold-water corals in the East Melilla Coral Province during Greenland Interstadial 1. A change in benthic foraminiferal communities and an increase in the sediment mean grain size mark the passage from the Early to Late Greenland Interstadial 1. The current velocity of intermediate water masses is suggested to have increased during the Early to Late Greenland Interstadial 1, whilst simultaneously fluvial input would have reduced. Such changes suggest that the climate became more arid during the second phase of Greenland Interstadial 1.

Functional differences in trophic structure of offshore wind farm communities: A stable isotope study

Abstract Turbidity is widely regarded for modulating primary production and influencing the distribution of submerged aquatic vegetation. Although less well studied, turbidity can also have significant effects on trophic interactions and food webs by modifying light penetration and scattering, influencing foraging ability of visual-hunting predators such as fishes. By interfering with visual foragers, turbidity may shift food webs towards predators that forage with other sensory modalities (e.g. chemoreception and mechanoreception), consequently altering food web structure. We analysed turbidity effects on estuarine community composition and biodiversity in the Gulf of Mexico by analysing an 18-year fisheries-independent data set and assessing communities inhabiting contemporary oyster reefs (Crassostrea virginica). In the long-term data set, elevated turbidity was associated with decreased fish species richness and diversity and higher abundances of benthic species that rely more on chemoreception for foraging and predator avoidance (e.g. crabs). High turbidity may provide a predation refuge for crabs and other benthic organisms that visually oriented fish prey upon. On oyster reefs, crabs readily consume suspension-feeding organisms including newly settled oysters and porcelain crabs (Petrolisthes armatus). Both were significantly less abundant in high turbidity. Human practices that increase turbidity may indirectly influence trophic interactions, species distributions, ecosystem function, and biodiversity.

Abstract Climate change is already transforming the seascapes of our oceans by changing the energy availability and the metabolic rates of the organisms. Among the ecosystem-engineering species that structure the seascape, marine animal forests (MAFs) are the most widespread. These habitats, mainly composed of suspension feeding organisms, provide structural complexity to the sea floor, analogous to terrestrial forests. Because primary and secondary productivity is responding to different impacts, in particular to the rapid ongoing environmental changes driven by climate change, this paper presents some directions about what could happen to different MAFs depending on these fast changes. Climate change could modify the resistance or resilience of MAFs, potentially making them more sensitive to impacts from anthropic activities (i.e. fisheries and coastal management), and vice versa, direct impacts may amplify climate change constraints in MAFs. Such changes will have knock-on effects on the energy budgets of active and passive suspension feeding organisms, as well as on their phenology, larval nutritional condition, and population viability. How the future seascape will be shaped by the new energy fluxes is a crucial question that has to be urgently addressed to mitigate and adapt to the diverse impacts on natural systems.

The Late Triassic and Early Toarcian extinction events are both associated with greenhouse warming events triggered by massive volcanism. These Mesozoic hyperthermals were responsible for the mass extinction of marine organisms and resulted in significant ecological upheaval. It has, however, been suggested that these events merely involved intensification of background extinction rates rather than significant shifts in the macroevolutionary regime and extinction selectivity. Here, we apply a multivariate modelling approach to a vast global database of marine organisms to test whether extinction selectivity varied through the Late Triassic and Early Jurassic. We show that these hyperthermals do represent shifts in the macroevolutionary regime and record different extinction selectivity compared to background intervals of the Late Triassic and Early Jurassic. The Late Triassic mass extinction represents a more profound change in selectivity than the Early Toarcian extinction but both events show a common pattern of selecting against pelagic predators and benthic photosymbiotic and suspension-feeding organisms, suggesting that these groups of organisms may be particularly vulnerable during episodes of global warming. In particular, the Late Triassic extinction represents a macroevolutionary regime change that is characterized by (i) the change in extinction selectivity between Triassic background intervals and the extinction event itself; and (ii) the differences in extinction selectivity between the Late Triassic and Early Jurassic as a whole.

An ichnological model for a deltaic depositional system: New insights from the Neogene Siwalik Foreland Basin of Darjeeling-Sikkim Himalaya