Marine Biodiversity最新文献

The starfish Luidia magnifica (Asteroidea: Paxillosida: Luidiidae) is a multiradiate starfish that occurs throughout the Indo-Pacific. Since the description of L. magnifica in 1906 by Fisher, very few observations of this species have been documented. We present new shallow-water records for L. magnifica in the Tropical Eastern Pacific obtained between 2017 and 2021. We collected a total of 15 specimens of L. magnifica in the bay of Manzanillo, Colima, in the central nearshore Mexican Pacific. We provide morphological description of specimens collected and additional ecological data. We used molecular techniques to verify species identification. This record represents a considerable expansion of the known distribution range of L. magnifica and provides the first evidence of the presence of this species in the Tropical Eastern Pacific. The presence of L. magnifica larvae from the Caribbean coast of Panama was also identified from DNA sequencing of larvae left unindentified in previous reports. This result indicates that it is possible that the L. magnifica also occurs in the Carribbean. Because observations of the starfish in the Mexican Pacific have been recent, the presence of larvae in the Caribbean could be a recent introduction through the Panama Canal from the Eastern Pacific to the Western Atlantic.

The species Mulinia lateralis (Say, 1822) is native to the western North Atlantic Ocean and was first documented in European coastal waters in 2017. Since then, M. lateralis was reported several times in large abundances in the coastal waters of the Netherlands, Belgium, and more scattered in Germany. While the introduction vector is still unclear, we assume that dispersal in the southern North Sea is driven by larval drift related to anti-clockwise residual tidal currents. To test this hypothesis and to document its current status in the central Wadden Sea, individuals were sampled systematically from intertidal flats along 10 transects ranging from the outer Ems River estuary in the west to the outer Elbe River estuary in the east (German North Sea coast) between February and May 2022. In total, 897 specimens of M. lateralis were sampled from 392 stations (mean abundance 2.3 ± 5.0 ind./m²). The shell length ranged between 4.0 and 23.6 mm. Regarding the increasing number of records of M. lateralis at multiple sites in Europe since 2017 and based on the data of this study, the species can be considered as established in the western and central Wadden Sea.

The pygmy seahorse, Hippocampus bargibanti Whitley, 1970 (Osterichthys: Syngnathidae), is an obligate symbiont of gorgonians. The seahorses mimic their host’s colors and shapes and are highly dependent on them. Their hosts are limited to five species of the genus Muricella (Octocorallia: Anthogorgiidae). Symbiosis with other Octocorallia genera has not been reported. However, the host gorgonians are difficult to identify due to limited availability of key taxonomic characteristics. In this study, we describe a pygmy seahorse living symbiotically with a gorgonian in the Kochi Prefecture, Shikoku, Japan. The gorgonian was dissected, morphologically characterized, and identified as a new host species from the genus Anthogorgia (Anthogorgiidae) rather than Muricella, based on differences in sclerite morphology. This is the first study to identify this genus as a host of H. bargibanti. Accurate understanding of host selectivity would be useful in the study of H. bargibanti conservation and ecology.

This study presents an assessment of the benthic community structure in the supra-, medio-, and upper infralittoral zones along the Çanakkale Strait, Turkey. Replicated samples were collected with cores and quadrats from 16 stations during the summer months of 2019. The average density of zoobenthos was estimated at 20,626 individuals m⁻² and average wet mass of phytobenthos was 652 g m⁻². In total, the community comprised 160 zoobenthic and 35 phytobenthic species. Nine species were new records for the Turkish Strait System, and five were non-native to the area. The study revealed that Oligochaeta (sp.) were the dominant zoobenthos taxa, followed by the amphipod species Speziorchestia stephenseni (Cecchini, 1928). Additionally, the red alga Ceramium virgatum Roth, 1797 was identified as the most abundant phytobenthic taxon. No statistically significant differences were found in the biomass of the phytobenthic and the abundances of the zoobenthic assemblages among the supra-, medio-, and infralittoral zones, only zoobenthos community have a weak but significant difference with soft and hard substrates. Furthermore, a statistically significant but weak relationship between zoo- and phytobenthic species is also reported. The study also examined correlations between abiotic properties on community structure. It was revealed that the sediment in the structure of medium gravel, fine gravel, and fine sand affected the structure of the benthic community in the three zones. Also, the distance of the sampling area to the zone boundaries affects the distribution of zoobenthic communities in the medio- and infralittoral zones. The findings of this study offer fundamental data for the development of ecosystem-based marine management plans and extensive monitoring programs for the coastlines of the Çanakkale Strait. This area serves as the biological corridor of the Marmara Sea, which was designated as a Special Environmental Protection Area (SEPA) in 2021, facing pressures from anthropogenic activities and climate change.

Hydroids are benthic cnidarians that have adapted to diverse marine environments through a wide variety of reproductive strategies and high phenotypic plasticity. This study aims at enhancing our understanding of the benthic hydroid diversity in underexplored areas of Brazil by analyzing hundreds of previously unexamined specimens. The study encompasses material collected from stations spanning the continental shelf and slope, ranging from the intertidal zone to a depth of 3,800 m across nine states in the North and Northeast regions of Brazil. This study represents the most extensive survey of benthic hydrozoans ever conducted in Brazil in terms of the sampled area, number of specimens collected, and bathymetric range. A total of 59 hydroid species, belonging to 32 genera and 14 families, were identified. In the states with the highest number of stations, we observed a greater number of specimens collected and, consequently, a greater richness, highlighting the importance of faunal surveys in neglected areas. The number of records and species richness declined with increasing depth, with 0–50 m exhibiting the highest number of records and species richness. Biogenic substrates, particularly sponges, hosted numerous epizoic hydroids. The significance of conducting new faunal surveys in underexplored areas of the Brazilian coastline is emphasized to address the knowledge gap regarding benthic hydrozoans in a vast area of the western South Atlantic.

Contemporary climate change in the Arctic is causing the reduction of the ice habitat. This process induces rearrangements in the community composition of ice-dwelling microbial eukaryotes, with heterotrophic picoeukaryotes being one of the least studied groups. Here, we report the results of a DNA metabarcoding investigation of heterotrophic picoeukaryote diversity in the ice of the Kandalaksha Gulf of the White Sea by Illumina high-throughput sequencing of the 18S rRNA V4 gene region. In total, 121 operational taxonomic units (OTUs) belonging to heterotrophic protists were revealed. The communities of heterotrophic picoeukaryotes in first-year ice were represented by seven eukaryotic domains (Stramenopiles, Alveolata, Rhizaria, Cryptista, Haptista, Apusozoa, Opisthokonta) and within 15 phyla. Rhizaria was the most dominant domain accounting for 48% of the total relative read abundance and included only Cercozoa. The taxonomic composition of heterotrophic picoeukaryotes was analyzed in detail with attention to rare and important microbial eukaryotes and unusual finds in sea ice habitats, such as the parasitic Perkinsea. Unknown Cercozoa clade was revealed. We have demonstrated that the White Sea heterotrophic picoeukaryote communities are diverse but insufficiently studied. Only 39% of OTUs were classified down to the order, family, or genus level, and only 11% of OTUs were classified to the genus level. This demonstrates that many unsequenced unicellular eukaryotes are found in sea ice and highlights some limitations of the V4 18S rRNA gene metabarcoding approach—the incompleteness of databases (lack of reference sequences) and shortness of the V4 region (inability to classify OTUs to species level).

Holothurians are the dominant megabenthic deposit feeders in the Peru Basin (SE Pacific) and feed to various degrees of selectivity on a heterogenous pool of sedimentary detritus, but drivers of feeding selectivity and diet preferences for most holothurian species are unknown. This study reconstructs the diets of 13 holothurian species of the orders Elasipodida, Holothuriida, and Synallactida. Bulk stable isotope analyses (δ¹³C, δ¹⁵N) of holothurian body wall and gut wall tissues, gut contents, and feces were combined with compound-specific stable isotope analyses of amino acids, phospholipid-derived fatty acids, and neutral-lipid-derived fatty acids in the body wall. We further assessed how holothurians in the Peru Basin partition their resources and calculated how much of the daily particulate organic carbon (POC) flux to the area is ingested by them using information about gut contents of nine species. To assess the dependence of holothurians on fresh phytodetritus, we performed in situ pulse-chase experiments using ¹³C- and ¹⁵N-enriched phytodetritus. By measuring the uptake of this phytodetritus in fatty acids and amino acids and by comparing it with the presence of these compounds in the sediment, we calculated net accumulation and net deficiency for specific fatty acids and amino acids and discussed how climate change might affect the dependence on specific compounds. A Sørensen–Dice coefficient-based cluster analysis using data from trophic levels, levels of heterotrophic re-synthesis of amino acids, feeding selectivity, and food sources/diet suggested two major trophic groups with two optional subgroups each. Species-specific traits of locomotion, tentacle morphology, and gut structure likely allow resource partitioning and differences in selectivity among the holothurians, of which a subpopulation of 65% of all specimens can ingest 4 to 27% of the daily POC flux to the Peru Basin. Holothurians are specifically dependent on the uptake of arachidonic acid from phytodetritus, while most essential amino acids are available in the Peru Basin in sufficient concentrations.

After 50 years, the dumping of red mud at the head of Cassidaigne Canyon (Southern France) was stopped in 2015. The area was surveyed in 2021 with an ROV at depths of 440–630 m. Biological findings reported here (images, sampling) have been obtained during a single ROV transect in the heavily impacted zone. In spite of the industrial waste deposit, a diverse faunal assemblage has persisted at the canyon head. Bioconstruction comprising large deep-sea oyster shells, scleractinian corals and hexactinellid sponge skeletons provides elevate and complex substrates for other organisms. Among the more significant findings, three live specimens of Neopycnodonte zibrowii Gofas, C. Salas & Taviani, 2009, previously only known as dead shells in that canyon, were documented and the rarely observed stenopodid shrimp Odontozona edwardsi (Bouvier, 1908) has been sampled (first record in the Mediterranean) and DNA barcoded.