Epibiotic Communities Research Articles

The epibiotic community associated to the European flat oyster: a function of the state of development of the reef

When healthy, Ostrea edulis populations are capable of creating remarkable biogenic reefs, providing a unique habitat for marine biodiversity. At present, the biotic assemblages associated with flat oysters remain poorly defined. This study aims to analyze biodiversity associated with the reef's development stage by focusing on its epibiotic community. The studied oyster population is an old remnant bed located in the Bay of Brest, which has been undergoing restoration for 5 years. The epibiotic communities (>500 μm) of scattered individual living (n = 10) and dead (n = 9) oysters, as well as of aggregates from the ground (n = 10) and from a restored reef (n = 3) were compared. 137 species associated with oysters were found, among which 22 were specific to individual oysters and 55 to aggregates and reefs. Although reef samples formed a distinct group in the SIMPER analysis, Shannon's (between 2.25 and 2.52) and Simpson's (between 0.84 and 0.86) diversity indices remained constant for each reef development stage. Piélou's indices (between 0.71 and 0.80) were significantly lower for aggregates displaying a less evenly distributed community. Mean abundance and species richness per sample were higher for aggregated structures. However, when standardized to abundance per centimeter square of shell surface, both parameters were significantly higher for individual oysters. Therefore, while reefs may support a higher species richness at a larger spatial scale, at a smaller scale, single oysters have a higher species richness per unit area of shell. Seemingly, despite the poor state of their remnant populations, flat oysters are still hosting important macrofaunal biodiversity.

Impact of Biotic and Abiotic Factors on Epibiotic Communities of the Barents Sea Red King Crab

Impact of Biotic and Abiotic Factors on Epibiotic Communities of the Barents Sea Red King Crab

Epibiotic Communities of the Senatorial Scallop Mimachlamys sanguinea (Linnaeus, 1758) (Bivalvia: Pectinidae) from the Expansion Channel of the Suez Canal, Egypt

Epibiotic Communities of the Senatorial Scallop Mimachlamys sanguinea (Linnaeus, 1758) (Bivalvia: Pectinidae) from the Expansion Channel of the Suez Canal, Egypt

Winter Epibiotic Community of the Red King Crab Paralithodes camtschaticus in Sayda Bay (Barents Sea).

The species composition of epibiotic communities on red king crab was investigated in Sayda Bay, Russia, during November of 2015 and 2016. The community consisted of 12 species in total. Among epibionts, the barnacle Balanus crenatus was most prevalent (67.0%), while the amphipod Ischyrocerus commensalis was the most frequent symbiont (77.3%). Infestation levels in May-June 2005 and September 2004 were higher, as a larger proportion of small crabs without fouling species were present during those seasons. The lower infestation intensities recorded for other common associated organisms during winter can be attributed to their increased mortality due to unfavorable temperature conditions. The localization of epibionts and symbionts were related to larval settlement patterns of attached species and feeding behavior of mobile species. Monthly growth increments for I. commensalis and B. crenatus were estimated at 2 mm in body length and 1.35 mm in basal diameter, respectively. Size-at-age data for epibionts can aid in the age determination of large male crabs that may skip an annual molt.

Current knowledge of the Southern Hemisphere marine microbiome in eukaryotic hosts and the Strait of Magellan surface microbiome project.

Host-microbe interactions are ubiquitous and play important roles in host biology, ecology, and evolution. Yet, host-microbe research has focused on inland species, whereas marine hosts and their associated microbes remain largely unexplored, especially in developing countries in the Southern Hemisphere. Here, we review the current knowledge of marine host microbiomes in the Southern Hemisphere. Our results revealed important biases in marine host species sampling for studies conducted in the Southern Hemisphere, where sponges and marine mammals have received the greatest attention. Sponge-associated microbes vary greatly across geographic regions and species. Nevertheless, besides taxonomic heterogeneity, sponge microbiomes have functional consistency, whereas geography and aging are important drivers of marine mammal microbiomes. Seabird and macroalgal microbiomes in the Southern Hemisphere were also common. Most seabird microbiome has focused on feces, whereas macroalgal microbiome has focused on the epibiotic community. Important drivers of seabird fecal microbiome are aging, sex, and species-specific factors. In contrast, host-derived deterministic factors drive the macroalgal epibiotic microbiome, in a process known as "microbial gardening". In turn, marine invertebrates (especially crustaceans) and fish microbiomes have received less attention in the Southern Hemisphere. In general, the predominant approach to study host marine microbiomes has been the sequencing of the 16S rRNA gene. Interestingly, there are some marine holobiont studies (i.e., studies that simultaneously analyze host (e.g., genomics, transcriptomics) and microbiome (e.g., 16S rRNA gene, metagenome) traits), but only in some marine invertebrates and macroalgae from Africa and Australia. Finally, we introduce an ongoing project on the surface microbiome of key species in the Strait of Magellan. This is an international project that will provide novel microbiome information of several species in the Strait of Magellan. In the short-term, the project will improve our knowledge about microbial diversity in the region, while long-term potential benefits include the use of these data to assess host-microbial responses to the Anthropocene derived climate change.

Symbioses of alvinocaridid shrimps from the South West Pacific: No chemosymbiotic diets but conserved gut microbiomes.

Rimicaris exoculata shrimps from hydrothermal vent ecosystems are known to host dense epibiotic communities inside their enlarged heads and digestive systems. Conversely, other shrimps from the family, described as opportunistic feeders have received less attention. We examined the nutrition and bacterial communities colonising 'head' chambers and digestive systems of three other alvinocaridids-Rimicaris variabilis, Nautilocaris saintlaurentae and Manuscaris sp.-using a combination of electron microscopy, stable isotopes and sequencing approaches. Our observations inside 'head' cavities and on mouthparts showed only a really low coverage of bacterial epibionts. In addition, no clear correlation between isotopic ratios and relative abundance of epibionts on mouthparts could be established among shrimp individuals. Altogether, these results suggest that none of these alvinocaridids rely on chemosynthetic epibionts as their main source of nutrition. Our analyses also revealed a substantial presence of several Firmicutes and Deferribacterota lineages within the foreguts and midguts of these shrimps, which closest known lineages were systematically digestive symbionts associated with alvinocaridids, and more broadly for Firmicutes from digestive systems of other crustaceans from marine and terrestrial ecosystems. Overall, our study opens new perspectives not only about chemosynthetic symbioses of vent shrimps but more largely about digestive microbiomes with potential ancient and evolutionarily conserved bacterial partnerships among crustaceans.

Bacterial Communities in a Gradient of Abiotic Factors Near a Sulfide Thermal Spring in Northern Baikal

The structure and diversity of microbial communities developing in the combined gradient of temperature (44–19 °C), as well as concentration of oxygen (0–10 mg/L) and hydrogen sulfide (33–0.7 mg/L), were studied in the thermal sulfide spring on the coast of Northern Lake Baikal. The predominance of bacteria participating in sulfur and nitrogen cycles and significant changes in the composition of microbial communities were noted at changing physicochemical conditions. Thiovirga sp. (sulfur-oxidizing bacteria, up to 37%) and Azonexus sp. (nitrogen-fixing bacteria, up to 43%) were dominant at high temperatures and concentrations of hydrogen sulfide in two hydrotherms. In addition, a significant contribution of the Rhodocyclaceae family (up to 51%) which is involved in the denitrification processes, and Acetoanaerobium sp. (up to 20%) fixing carbon oxide were found in the spring water. In the stream, mainly oxygenic cyanobacteria (up to 56%) developed at a temperature of 33 °C, in the presence of hydrogen sulfide and oxygen. In addition, sulfur bacteria of the genus Thiothrix (up to 48%) found in epibiotic communities of benthic animals of Lake Baikal were present here. Thiothrix sp. formed massive fouling in the zone of mixing lake and thermal waters with a significant contribution of hydrogen-oxidizing bacteria of the genus Hydrogenophaga (up to 22.5%). As well as chemolitho- and phototrophic bacteria, chemoorganotrophs (phyla Firmicutes, Chloroflexi, Desulfobacterota, Nitrospirota, Fibrobacterota, etc.) have been identified in all communities. The chemical parameters of water in spring and coastal zones indicate a significant change in the composition of thermal waters occurring with the participation of diverse microbial communities that contribute to the assimilation of inorganic components of mineral thermal waters.

Epibionts of an Introduced King Crab in the Barents Sea: A Second Five-Year Study

The biodiversity, infestation patterns, and spatial distribution of organisms living in association with the introduced red king crab Paralithodes camtschaticus were studied in Dalnezelenetskaya Bay, southern Barents Sea, in 2009–20013 to update a list of species, reveal long-term changes in this epibiotic community, and identify key factors affecting the prevalence and intensity of infestation. A total of 90 associated species were found throughout the study period, or twice as many as in 2004–2008, reflecting relatively low similarity between these periods. Half of the species were found on one to three crabs only. Copepods had the maximum diversity (23 species). For the first time, macroalgae were found as epibionts of red king crabs. Overall, the highest prevalences were found for the amphipod Ischyrocerus commensalis (74.2%), the copepods Tisbe furcata (57.7%) and Harpacticus uniremis (29.4%), the amphipod Ischyrocerus anguipes (27.3%), and the fish leech Johanssonia arctica (16.2%). Redundancy analysis showed that host size was the most important driver of species abundance, followed by shell condition, water temperatures in the coastal Barents Sea in May and June, and sex. These factors, coupled with the range expansion of red king crabs and climate changes in the Barents Sea, provide good explanations for the differences between the 2004–2008 and 2009–2013 fouling communities. Distribution patterns for common taxa on the host reflect larval settlement patterns and/or relationships between the host and associated species. These results expand our knowledge of infestation patterns for the invasive red king crab and provide a reference point for further monitoring.

A comparative analysis of the epibiotic community on pneumatophore and artificial substratum in a mangrove ecosystem, south-west coast of India

Marine biology,marine ecology,Phytoplankton, marine algae, zooplankton, nekton, benthos, corals and coral reefs, ecology, zoogeography and systematics, primary production and experimental work on ecosystem including energy flow at different trophic levels, population dynamics and theoretical models, recycling of matter, influence of environmental factors on metabolic activity, marine microbiology, mariculture and experimental work on propagation of cultivable species, biology of fishes, marine reptiles, sea birds and mammals, physical, chemical, geological and meteorological features of the environments related to marine biology, marine environmental damage caused by pollution and engineering works, underwater observations, conservation of living resources, modifications in methodology and techniques and development of new apparatus related to marine sciences

Full-length 16S rRNA amplicon sequencing reveals the variation of epibiotic microbiota associated with two shrimp species of Alvinocarididae: possibly co-determined by environmental heterogeneity and specific recognition of hosts.

Shrimps of the family Alvinocarididae, endemic species to deep sea chemosynthetic ecosystems, harbor epibiotic microbes on gills which probably play important roles in the survival of the shrimps. Among them, Alvinocaris longirostris and Shinkaicaris leurokolos occupy different ecological niches within the same hydrothermal vent in Okinawa Trough, and A. longirostris also exists in a methane seep of the South China Sea. In this study, full-length 16S rRNA sequences of the gill associated bacteria of two alvinocaridid species from different chemosynthetically ecological niches were first captured by single-molecule real-time sequencing. Totally, 120,792 optimized circular consensus sequences with ∼1,450 bp in length were obtained and clustered into 578 operational taxonomic units. Alpha diversity analysis showed seep A. longirostris had the highest species richness and evenness (average Chao1 = 213.68, Shannon = 3.39). Beta diversity analysis revealed that all samples were clearly divided into three groups, and microbial community of A. longirostris from seep and vent were more related than the other comparisons. By permutational multivariate analysis of variance, the most significant community compositional variance was detected between seep A. longirostris and vent S. leurokolos (R2 = 0.731, P = 0.001). The taxon tags were further classified into 21 phyla, 40 classes, 89 orders, 124 families and 135 genera. Overall, the microbial communities were dominated by Campylobacteria and Gammaproteobacteria. Alphaproteobacteria, Bacteroidia, Verrucomicrobiae, Bacilli and other minor groups were also detected at lower abundance. Taxonomic groups recovered from the vent S. leurokolos samples were only dominated by Sulfurovaceae (94.06%). In comparison, gill-associated microbiota of vent A. longirostris consisted of more diverse sulfur-oxidizing bacteria, including Sulfurovaceae (69.21%), Thiotrichaceae (6.77%) and a putative novel Gammaproteobacteria group (14.37%), while in seep A. longirostris, Gammaproteobacteria un-group (44.01%) constituted the major component, following the methane-oxidizing bacteria Methylomonadaceae (19.38%), and Sulfurovaceae (18.66%). Therefore, the gill associated bacteria composition and abundance of alvinocaridid shrimps are closely related to the habitat heterogeneity and the selection of microbiota by the host. However, the interaction between these alvinocaridid shrimps and the epibiotic communities requires further study based on metagenome sequencing and fluorescence in situ hybridization.

Filling a Gap: A Population of Eunicella verrucosa (Pallas, 1766) (Anthozoa, Alcyonacea) in the Tavolara-Punta Coda Cavallo Marine Protected Area (NE Sardinia, Italy)

Among Mediterranean habitat-forming alcyonaceans, the sea fan Eunicella verrucosa is known to form dense forests at circalittoral depths, providing seascape complexity and sustaining a rich associated fauna. Its occurrence in the Tavolara–Punta Coda Cavallo Marine Protected Area (NE Sardinia) has never been deeply investigated despite this area being well known from a biocoenotic point of view. This study provides new information on the size of the colonies settled between 35 and 59 m depth on granitic outcrops and represents a contribution to highlighting the hotspot of megabenthic diversity enclosed in the protected area. The presence of 100 colonies was assessed by photographic samplings performed between 2015 and 2020, in a small area characterized by peculiar ecological conditions. The morphometric descriptions and age estimation showed a persistently isolated population probably derived from a stochastic event of settling of larvae presumably coming from the Tuscany Archipelago. A richly associated epibiotic community, composed of 18 species/OTUs, showed how branched bryozoans, particularly Turbicellepora avicularis, and the parasitic octocoral Alcyonium coralloides, affected the colonies’ branches, suggesting a putative anthropogenic impact related to fishing activity. This study indicates that proper protection and management strategies are mandatory for the Marine Protected Area, in order to conserve this unique population and the whole associated benthic assemblage.

A deep dive into the epibiotic communities on aquacultured sugar kelp Saccharina latissima in Southern New England

Sugar kelp cultivation at the southern end of its range on the east coast of North America is being pursued commercially for human consumption, which demands a high-quality product. Blade quality can be compromised by attached organisms – epibionts. Biweekly examination of epibionts on sugar kelp was conducted April–May 2018, on a kelp farm in eastern Long Island Sound, CT, USA. Culturable Vibrio spp. were not present on kelp blades until May and were limited to only old sections. No Vibrio colonies were human pathogens V. parahaemolyticus or V. vulnificus, based upon ToxR-specific multiplex PCR assays. Neither epibenthic cyanobacteria Lyngbya spp. nor the dinoflagellate Prorocentrum lima, microbes of concern because of toxigenicity, were detected on kelp by microscopy or metabarcoding of partial rRNA genes. The lacy bryozoan was the only epibiotic animal observed that could cause damage to kelp, but its abundance was low.Summarizing most-common sequence reads, Gammaproteobacteria was the most abundant bacterial group on kelp blades (49%) and Alphaproteobacteria were the most abundant in seawater (39%). Bacillariophyta were the most abundant eukaryotes on kelp blades (36%) and Dinoflagellata were the most abundant eukaryotes in seawater (43%). Molecular operational taxonomic unit matrices were used for non-metric multidimensional scaling; the most prominent structure for both prokaryotic and eukaryotic communities was the separation between blade and seawater samples. This spatial separation explained 81% and 76% of the variation among prokaryotic and eukaryotic samples, respectively. Indicator Species Analysis identified Gammaproteobacteria (55%) and Bacillariophyta (56%) to be the most important blade indicator prokaryotes and eukaryotes, respectively. A closer examination of indicator species temporal patterns and their ecophysiology suggested that Aquimarina, Parcubacteria, and Peronosporomycetes are potential pathogens to sugar kelp. Ciliates may be the most important grazers that keep epiphytes (Bacillariophyta, Rhodophyta, and Phaeophyta) and Peronosporomycetes on kelp in check.

Microbial epibiotic community of the deep-sea galatheid squat lobster Munidopsis alvisca

Life at hydrothermal vent sites is based on chemosynthetic primary producers that supply heterotrophic microorganisms with substrates and generate biomass for higher trophic levels. Often, chemoautotrophs associate with the hydrothermal vent megafauna. To investigate attached bacterial and archaeal communities on deep-sea squat lobsters, we collected ten specimens from a hydrothermal vent in the Guaymas Basin (Gulf of California). All animals were identified as Munidopsis alvisca via morphological and molecular classification, and intraspecific divergence was determined. Amplicon sequencing of microbial DNA and cDNA revealed significant differences between microbial communities on the carapaces of M. alvisca and those in ambient sea water. Major epibiotic bacterial taxa were chemoautotrophic Gammaproteobacteria, such as Thiotrichaceae and Methylococcaceae, while archaea were almost exclusively represented by sequences affiliated with Ca. Nitrosopumilus. In sea water samples, Marine Group II and III archaea and organoheterotrophic Alphaproteobacteria, Flavobacteriia and Planctomycetacia were more dominant. Based on the identified taxa, we assume that main metabolic processes, carried out by M. alvisca epibiota, include ammonia, methane and sulphide oxidation. Considering that M. alvisca could benefit from sulphide detoxification by its epibiota, and that attached microbes are supplied with a stable habitat in proximity to substrate-rich hydrothermal fluids, a mutualistic host-microbe relationship appears likely.

Epibiont assemblages on limpet shells: Biodiversity drivers in intertidal rocky shores

Limpet shells can harbour a high diversity of species. Individuals of four limpet species (Patella depressa, Patella ulyssiponensis, Patella vulgata and Siphonaria pectinata) were collected monthly during one year in southern Portugal. Epibiont organisms were identified, counted and the percentage cover of facilitator taxa was also recorded. A total of 86 taxa were identified with abundance reaching 674 epibionts on a single basibiont shell. P. ulyssiponensis showed the highest epibiont species diversity and richness while P. depressa and P. vulgata showed similar diversity and richness. P. depressa had a more even epibiotic community mainly due to higher densities of Chthamalus sp. Overall, basibiont species was the key factor determining the epibiotic community, followed by month/season and erect algae. The presence of erect algae potentiated the epibionts diversity on limpet shells, whereas the occurrence of barnacles tended to decrease it and the presence of crustose algae had no significant effect on epibionts diversity. These findings shed further light on the biological and ecological complex relationships among keystone species inhabiting intertidal rocky shores.

Microbial epibiotic community of the deep-sea galatheid squat lobster Munidopsis alvisca

Microbial epibiotic community of the deep-sea galatheid squat lobster Munidopsis alvisca

Epibiotic Communities of Common Crab Species in the Coastal Barents Sea: Biodiversity and Infestation Patterns

Crabs are important ecosystem engineers in marine habitats worldwide. Based on long-term data, we analyzed the species composition and infestation indices of epibionts and symbionts colonizing the great spider crab, Hyas araneus, and two lithodid crabs—the northern stone crab, Lithodes maja, and the red king crab, Paralithodes camtschaticus—in the coastal zone of the Barents Sea. The epibiotic communities found on great spider crabs were closer to northern stone crabs (33%) compared to red king crabs (25%). The prevalence of mobile symbionts (amphipods, Ischyrocerus, and polychaetes, Harmothoe) and common epibionts, such as barnacles and hydrozoans, was low on great spider crabs and high on the body and in the gills of lithodid crabs. Epiphytes were abundant on great spider crabs but not present on both species of lithodid crabs. Egg symbionts found on H. araneus and P. camtschaticus do not affect their local populations. Differences in the fouling communities found on the three crab species are associated with host size range, surface properties of their carapaces, and behavior patterns.

Epibiotic associations with the deep-sea pycnogonid Nymphon hirtipes Bell, 1855 as a source of biodiversity

Among arthropods, pycnogonids are generally considered of minor ecological significance in marine ecosystems. However, the fact that they can host a wide diversity and high abundance of epibiotic organisms suggests that their role in benthic communities may be underestimated. The present study characterized the diversity, dynamics and role of the epibiotic community associated with deep-sea pycnogonids (Nymphon hirtipes). Despite their small size, they hosted a mean of 62 macro-organisms belonging to at least 26 species from 11 different phyla. Foraminifera was the dominant phylum while other phyla, such as Bryozoa, Cnidaria (Hydrozoa), Porifera and Brachiopoda were common. The macro-epibiont burden varied from 1 to 235 organisms per pycnogonid; it was consistent across depths and locations but fluctuated as a function of sex and of the reproductive state in males. Specifically, most colonized individuals were females, which are larger and thus offer more surface for epibionts. Among males, burdens peaked in those carrying larvae. Maximum epibiont burden and coverage was correlated with the cessation of grooming at the beginning of the breeding period. Micro-epibionts consisted of bacterial mats covering most body parts. Several epibionts were estimated to have negative effects on their host (e.g. increasing drag, preventing mating, decreasing limb mobility and impeding feeding). However, because this species dies after reproducing, epibiosis may be considered as a positive trade-off since it may provide food to the mobile juveniles living on the male for several months. Furthermore, epibionts could be used as camouflage during this period. N. hirtipes has been identified as a common component of the benthofauna in the deep sea of the North Atlantic and Arctic Oceans, and the present study indicates that it displays the greatest diversity and burden of associates ever reported among pycnogonids.

Biodiversity patterns of epibiotic invertebrates occupying an edible polyplacophoran across a latitudinal gradient of the Mexican Pacific

The broad perspective regarding marine-organisms biodiversity indicates a latitudinal gradient. Understanding gradients in diversity at large scales has important applications for understanding future impacts on local and regional communities. We use and propose the edible mollusk Chiton articulatus as the basibiont proxy to analyze the spatio-temporal changes in biodiversity patterns of the epibiotic community occupying its scleritome surface. The analyses covered approximately 1817 km of the Mexican Pacific, using seven sites that included samples from Sinaloa “SIN” (23°38′N, 106°48′W); Nayarit “NAY” (20°45′N, 105°22′W); Jalisco “JAL” (19°13′N, 104°41′W); Colima “COL” (19°06′N, 104°20′W); Michoacan “MIC” (17°54′N, 102°11'"W); Guerrero “GRO” (16°48′N, 99°52′W) and Oaxaca “OAX” (15°39′N, 96°30′W). A temporal gradient (monthly sampling from October 2015 to October 2016) was also analyzed. Evaluation of the sampling effort demonstrated that 76–86% of the epibiotic fauna was recovered. The most representative epibionts were barnacles, a limpet and an acrothoracican. Abundances of the barnacles and the limpet tended to decrease southwards, while the acrothoracican tended to increase northwards. The epibiotic community did not exhibit the typical latitudinal gradient of diversity expected, but a fragmented pattern within three main areas, which coincide with three of the marine biogeographic ecoregions proposed for the shallow waters of the Warm Temperate Northern Pacific and Tropical Eastern Pacific provinces. These were a northern group within SIN, which belong to the southern border of the Magdalena Transition ecoregion (subtropical); a middle group within NAY, JAL, COL, MIC, and GRO, which belongs to the Mexican Tropical Pacific ecoregion (tropical); and a southern group within OAX exclusively, belonging to the northern border of the Chiapas-Nicaragua ecoregion (tropical). The southern localities showed larger dominances and the central localities exhibited more stable communities. Our evidence suggests that as we move across the different shore types of the Mexican Pacific, the coastline supports distinct biotic assemblages, and the community on the rocky shores is biologically heterogeneous and mainly influenced by conditions at the local level. In consequence, conservation and protection efforts should consider preserving the local heterogeneity of habitats in the study area. Furthermore, since C. articulatus is edible, its epibiota represents an incidental fishing bycatch, with the result that the extraction of the chiton and its epibiota can jeopardy the diversity in the intertidal rocky shore of the Mexican Pacific.

Spatio-temporal occurrence patterns of epibiota along the leaves of the seagrass Cymodocea nodosa in the Northern Adriatic Sea

ABSTRACT We investigated the epibiotic community along Cymodocea nodosa leaves in a seagrass meadow in the Northern Adriatic Sea. In accordance with previous studies, we found that autotrophic organisms dominated throughout the study period (May–October 2014) and showed a clear temporal occurrence pattern with highest occurrence frequencies during summertime. Low relative occurrence of autotrophs was observed in spring, coinciding with higher values for sessile heterotrophs. In both autotrophs and heterotrophs, we observed a general trend towards increased epibiota cover on old leaves and towards the apical (i.e. older) parts of leaves, even though this pattern does not hold true for all species or sampling times. Most heterotrophs were rarely observed, but serpulid polychaetes, the foraminiferan Tretomphaloides concinnus, the hydrozoan Clytia linearis as well as gastropod clutches occurred frequently on all parts of the leaves and showed occurrence patterns putatively reflecting spatial competition with autotrophs and predator avoidance. Hitherto, few data have been available on the epifaunal diversity and community structure on C. nodosa. Thus, this study provides important baseline data for future studies investigating the impact of natural and anthropogenic stressors on epibiota communities associated with this ecologically important Mediterranean seagrass species.

An ecological baseline for Laminaria hyperborea forests in western Ireland

AbstractThe biodiversity associated with subtidal Irish kelp forests dominated by Laminaria hyperborea has never been described. To enumerate species assemblages in these ecosystems, subtidal surveys were done throughout the calendar year to investigate species assemblages within kelp forests, composition of benthic communities, species colonizing kelp thalli, recruitment to kelp forests, and habitat recovery processes after canopy clearances. Surveys were further undertaken in maërl beds, sediment‐bottom bays, Serpula vermicularis reefs, and bedrock habitats for comparison. Across all four seasons, kelp forests harbor the richest species assemblages, second only S. vermicularis reefs in diversity, with a total of 313 unique species in the habitat (from juvenile recruits to mature macrofauna). Peak diversity in kelp forests occurred in summer and echinoderms were one of the most abundant groups, though urchins never reach densities that would threaten over‐grazing. The thalli of L. hyperborea are diverse habitats harboring many deposit feeders, filter feeders, and marine macroalgae. Epibiotic communities become more diverse with age of kelp, culminating in a maximum of 1660 individuals on stipes and 949 on holdfasts. Recruitment of crustaceans, echinoderms, and worms was high in kelp forests, but recruitment of common Irish fish could not be monitored because of unique life history stage. Habitat establishment took over a year on artificial substrata which were colonized by macroalgae and dense canopy cover inhibited growth of juvenile sporophytes. This descriptive study represents an essential baseline for kelp forest biodiversity in Ireland.