Marine Biodiversity最新文献

The Wadden Sea is an important habitat for a large number of fish species, supporting functions such as reproduction, breeding and feeding. The hooknose (Agonus cataphractus, Linnaeus, 1758) is a resident demersal fish species of the Wadden Sea, but due to its non-commercial importance it is rarely studied. In the present study, the feeding strategy and prey selection of the hooknose related to the benthic in- and epifauna in the field were investigated in six different habitat types (circalittoral sand, circalittoral mud, circalittoral mixed sediments, circalittoral coarse and gravel sediments, sublittoral sandbanks and reefs) in coastal waters of the German Wadden sea between 2020 and 2021. The stomach contents of A. cataphractus were dominated in most of the habitat types by very mobile epibenthic prey species, mainly the brown shrimp (Crangon crangon, Linnaeus, 1758), amphipods (Ampelisca spp., Microprotopus maculatus, Norman 1867) and cumaceans (Diastylis bradyi, Norman 1879, Pseudocuma longicorne, Bate 1858), similar to the benthic communities in the field. Infauna species such as the tube-building polychaete Lanice conchilega (Pallas 1766) were rarely consumed and potentially avoided due to their ability to withdraw below the feeding depths. Our results further showed habitat-specific differences in the hooknose diet, especially in reefs, where skeleton shrimps (caprellids) dominated the diet. The habitat type also influences the condition of A. cataphractus being highest in reefs but lowest on sandbanks. Our results highlight the importance of knowledge functional relationships between smaller-sized Wadden Sea fish species and its typical habitats, which in turn is essential for applicable management measures of the whole Wadden Sea area.

Crustaceans are one of the most widespread and speciose groups of marine organisms, fulfilling multiple ecological roles in numerous ecosystems. On coral reefs, many crustacean species form associations with scleractinian corals. Although the Red Sea is considered a biodiversity hotspot, few studies examined the diversity of coral-associated crustacean communities to date. In this study, 460 decapod crustaceans were recovered from 67 coral colonies of the three branching genera Acropora, Pocillopora and Stylophora in the central Saudi Arabian Red Sea. Crabs and shrimps were morphologically identified to the lowest taxonomic level possible, and portions of the mitochondrial COI and 16S rRNA genes were amplified with the objective of assessing their diversity and phylogenetic relationships. Finally, patterns of co-occurrence were evaluated to investigate the presence of species-specific symbiotic epifauna on different host corals. Overall, we recovered four families, five genera, and nine species of Red Sea crabs, nested into 11 molecular clades, and two families, eight genera and 11 species of shrimps, grouped within 12 lineages. Crabs of the species Trapezia tigrina were found to be exclusively associated with Pocillopora corals, while Tetralia crabs and the shrimps Jocaste japonica and Harpilius lutescens only occurred on Acropora colonies, providing evidence that potential loss of host corals due to local and global impacts could lead to consequent shifts in the symbiotic communities on reefs and to the loss of certain associated taxa. This study represents an advancement towards the understanding and molecular characterization of coral-associated benthic communities in the Red Sea and lays the ground for further research assessing the patterns of biodiversity, evolution, and ecological preferences of these organisms in the area.

Climate change effects on coastal ecosystems vary on large spatial scales, but can also be highly site dependent at the regional level. The Wadden Sea in the south-eastern North Sea is warming faster than many other temperate coastal areas, with surface seawater temperature increasing by almost 2 °C over the last 60 years, nearly double the global ocean mean increase. Climate warming is accompanied by rising sea levels, which have increased by approximately 2 mm yr⁻¹ over the last 120 years. For this sedimentary coast, the predicted acceleration of sea-level rise will have profound effects on tidal dynamics and bathymetry in the area. This paper synthesises studies of the effects of ocean warming and sea level rise in the northern Wadden Sea, largely based on research conducted at the Wadden Sea Station Sylt of the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research. An increasing rate of sea level rise above a critical threshold will lead to coastal erosion and changes in sediment composition, and may cause the transition from a tidal to lagoon-like environment as tidal flats submerge. This involves changes to coastal morphology, and the decline of important habitats such as muddy tidal flats, salt marshes and seagrass meadows, as well as their ecological services (e.g. carbon sequestration). Ocean warming affects plankton dynamics and phenology, as well as benthic community structure by hampering cold-adapted but facilitating warm-adapted species. The latter consist mostly of introduced non-native species originating from warmer coasts, with some epibenthic species acting as ecosystem engineers that create novel habitats on the tidal flats. Warming also changes interactions between species by decoupling existing predator–prey dynamics, as well as forming new interactions in which mass mortalities caused by parasites and pathogens can play an understudied but essential role. However, Wadden Sea organisms can adapt to changing abiotic and biotic parameters via genetic adaptation and phenotypic plasticity, which can also be inherited across generations (transgenerational plasticity), enabling faster plastic responses to future conditions. Important research advances have been made using next-generation molecular tools (-omics), mesocosm experiments simulating future climate scenarios, modelling approaches (ecological network analysis), and internet-based technologies for data collection and archiving. By synthesising these climate change impacts on multiple levels of physical and biological organisation in the northern Wadden Sea, we reveal knowledge gaps that need to be addressed by future investigations and comparative studies in other regions in order to implement management, mitigation and restoration strategies to preserve the uniqueness of this ecosystem of global importance.

Two new neotypes designations are proposed for the species Siboglinum besnardi and Siboglinum nonatoi, based on specimens collected from the Southwestern Atlantic deep waters, type locality of both species. This designation is necessary due to the loss of the original type series for both species. Species identities were validated through morphological analyses, and comprehensive redescriptions are conducted for both species, which not only expand upon the original descriptions but also introduce additional diagnostic characters, including stereomicroscope and SEM images. In addition, genetic material from a specimen of Siboglinum besnardi was obtained, enabling a molecular phylogenetic analysis utilizing COI, 16S and 28S molecular markers. This analysis confirmed not only the species placement within the family Siboglinidae but also provided substantial support for the monophyly of the Frenulata, Vestimentifera, Monilifera and Osedax groups within the annelid family Siboglinidae.

This is the first survey of marine tardigrades from the British Virgin Islands, though two species were previously reported from St. Croix, U.S. Virgin Islands. In June 2016, we collected subtidal and intertidal sand samples from various locations throughout the British Virgin Islands. We found 602 tardigrades in 18 of 21 samples, and these included 12 taxa, one of which, Batillipes wyedeleinorum sp. nov., is new to science and described here. We compared abundance and species diversity in intertidal and subtidal samples and found significantly greater abundance in intertidal habitats but no significant difference in the number of observed species between the two habitats. We calculated Chao 1 species richness, which indicated higher estimated richness in intertidal habitats and 15 ± 3.7 species (x̅ ± SD) in both habitats combined. Non-metric Multidimensional Scaling revealed differences in species composition between the two habitats with some species showing clear preferences for one or the other.

Gelatinous zooplankton (GZ), and pelagic tunicates specifically, plays key roles in marine ecosystems, contributing to diets of various predators and oceanic carbon cycling. Nevertheless, biological inventories are often lacking, but are essential in establishing marine biodiversity baselines that, in turn, are critical in detecting broad-scale changes. The use of social media in combination with scientific records provides a powerful tool to broaden the scope of biodiversity studies. This study assesses the diversity of pelagic tunicates (appendicularians and thaliaceans) in the Cuban Exclusive Economic Zone (EEZ) and whether the EEZ acts as an ecotone between the Gulf of Mexico (GoM) and the Caribbean Sea (CS). By reviewing the scientific literature and using citizen science data, a total of 28 species were identified. The most diverse family among the appendicularians was Oikopleuridae (9 species) and among the thaliaceans Salpidae (6 species). Cuba’s northern EEZ was more speciose compared to the southern EEZ, 18 versus 14 species. No endemic species were found in Cuba’s waters and tunicate assemblages were most similar to the GoM. Our data do not support that Cuban waters act as an ecotone (for pelagic tunicates) between the GoM and CS faunas. The study highlights the importance of these GZ in marine food webs and their scarce knowledge in the region. Further long-term studies are required to understand spatiotemporal patterns and ecological roles of tunicates in Cuban ecosystems.

Squat lobsters (family Galatheidae Samouelle, 1819) inhabiting shallow reefs are small crustaceans that can exhibit bright colors and include many cryptic species. Despite being a group with active taxonomists, basic details on their natural history, population structure, ecological associations, and even live coloration patterns remain largely unknown for many species. After a 2-week expedition aimed to conduct general collections of crustaceans from Guam, we recorded several new galatheids, including two new species. We sequenced the universal barcode region of the mitochondrial gene COI using Oxford Nanopore Technology to study the molecular diversity of squat lobsters in Guam and to detect potential species complexes across the Central Pacific. As a result, we describe the two new species, Coralliogalathea viridis Rodríguez-Flores & Giribet sp. nov. and Galathea calcifer Rodríguez-Flores & Giribet sp. nov., and provide new records and new data on the phylogenetic relationships, natural history, coloration patterns, geographic distribution, and biological associations of a total of ten species of galatheid squat lobsters.

A cleaning station used by juvenile green sea turtles, Chelonia mydas, was found in Brewers Bay, St Thomas, US Virgin Islands. Video observations identified three fish species previously undocumented to participate in this symbiotic relationship. From May 7th to August 12, 2020, a total of 27 h of video recordings of this cleaning station were made during various times throughout the daylight hours resulting in the capture of 612 min of cleaning behavior which consisted of 108 separate cleaning events. At least six green turtles were observed using the cleaning station, but the exact number of turtles could not be confirmed as individual turtles could not always be recognized. Large fish, such as barracudas and jacks, were also observed using the same cleaning station. Turtles were observed using the cleaning station for self-cleaning and cleaning by fish. Juvenile French angelfish, Pomacanthus paru, juvenile Queen angelfish, Holacanthus ciliaris, and small schools of slippery dick wrasses, Halichoeres bivittatus, were observed cleaning green turtles. The angelfish cleaned mainly the head, carapace, and plastron, while the wrasses cleaned mostly the soft parts of the turtle, which suggests some nitch partitioning. The most extended observed cleaning session was 69 min. However, short sessions were more common, with an average duration of 6.2 min and a median duration of 3.0 min. Self-cleaning was performed by rubbing on nearby rocks and a polypropylene rope suspended above the cleaning station. The shared use of a cleaning station and its cleaner fish by multiple turtles likely reduces the epizootic load on the turtles but may increase the transmission of diseases such as fibropapillomatosis. No statistical difference in the duration of cleaning was detected between turtles with and without apparent tumors during the limited observations of this study. Additional research is needed, but these findings may help determine the role of these cleaner fish in the ecology of marine ecosystems and the health of green sea turtles in the Caribbean.