Marine Biodiversity最新文献

The macrofauna in soft sediments of the deep seafloor is generally diverse and represents a comparatively well-studied faunal group of deep-sea ecosystems. In the abyss of the Clarion Clipperton Fracture Zone (CCFZ) in the NE Pacific, macrofauna are major contributors to benthic biodiversity. Their distribution, composition, and diversity have been frequently investigated to assess the potential impacts of future mining activities on the resident fauna. In this study, patterns of densities and community structure of CCFZ macrobenthic infauna and their relationships with a range of environmental and climatic variables were examined, with a special focus on communities from the eastern German contract area (referred to as BGR CA). However, comparisons were also made with other contractor areas (e.g., IFREMER, IOM, GSR) and one Area of Particular Environmental Interest (APEI3). Material for this study was obtained by means of a box corer during six expeditions to the CCFZ between 2013 and 2018 resulting in 148 samples. Our study uncovered notable spatial and temporal variations in both faunal densities and community composition. While areas within the BGR CA exhibited a similar community composition, slight differences were observed between the various CAs and APEI3. Surprisingly, we found an unexpected negative correlation between food availability and both macrofaunal density and community structure that may be attributed to differences in sampling methodologies and pronounced temporal variation. Furthermore, we explored the impact of climatic fluctuations associated with the El Niño/Southern Oscillation (ENSO) on macrofaunal densities, observing an increase during warm (El Niño) events. Our findings underscore the challenges of accurately assessing spatial and temporal variations in the absence of standardised sampling protocols. Hence, we emphasize the importance of adopting standardised protocols to enhance data comparability, thereby fostering a deeper understanding of the underlying factors influencing spatial and temporal changes in macrofauna community structure within the CCFZ.

Sharks rubbing against ocean floor or rocks are common events in marine environments, while instances of interspecific shark chafing behavior have been observed much less frequently. This behavior has garnered scientific interest in recent years and usually involves a smaller shark rubbing against a larger species, utilizing dermal denticles to rid itself of parasites or dead skin cells. Despite the costs and benefits of this behavior being not yet fully understood, we report new evidence of grey reef sharks (Carcharhinus amblyrhynchos Bleeker, 1856) engaging in chafing behavior against whale shark (Rhincodon typus Smith, 1828) in the Maldives. This behavior suggests that grey reef sharks may engage in chasing behavior for cleaning purposes or take advantage of larger sharks as an anti-predation tactic. These records contribute to shed light on previously unexplored aspects of elasmobranch interspecies interactions and highlight the need for further research into this topic. The prevalence of such behavior across different regions suggests its potential significance in the ecological dynamics of shark population.

Metridium senile (Linneaus, 1761) is simultaneously one of the most familiar sea anemones in temperate shallow water and a species embroiled in taxonomic and nomenclatural confusion. Their large body size, characteristic ruff of tentacles, and ability to thrive on artificial and natural substrates make these animals conspicuous and common on rocky ledges, pilings, wharfs, shipwrecks, and bivalve reefs. Their reported range encompasses all temperate habitats in the northern hemisphere plus a handful of locales in the temperate southern hemisphere that have typically been characterized as anthropogenic introductions. Understanding the range of M. senile has been confounded by confusion about its circumscription relative to its congeners and inconsistency in the names used. Here, we summarize the taxonomy of the genus and clarify the status of M. senile. Based on results of recent phylogenetic studies, we consider Metridium to have two valid species: M. farcimen (Brandt, 1835) and M. senile. We recognize M. senile as the valid, appropriate name for all populations of Metridium in the Atlantic and for some of the populations in the Pacific. We consider M. dianthus (Ellis, 1767), M. exile Hand 1955, M. huanghaiense Pei, 1998, and M. sinensis Pei, 1998 to be junior synonyms of M. senile. We clarify the differences between M. senile and M. farcimen, and comment on the status of M. canum Stuckey, 1914.

In order to counteract heavy foreland losses in the lower reaches of the Weser estuary, a system of sedimentation fields surrounded by brushwood groynes was constructed in 1958. Over the next forty years, the land accretion process was monitored by surveys of bottom-surface elevation, sedimentology, development of vegetation cover and changes in bottom-fauna composition. From the viewpoint of coastal protection, the sedimentation fields achieved a continuous growth of half a metre within forty years and successfully reduced the regression of the eroding shoreline. The ecological results represent a documentation comprising all succession stages from a bare tidal flat to a vegetated salt marsh. However, though the larger parts of the fields had already exceeded mean high-water level at the final survey of 1997, aquatic elements were still present in the vegetation as well as in the bottom fauna. The lack of a seaward inclination was most likely the reason, why saline water from spring tides and storm surges remained enriched in the soil. With growing elevation and condensing vegetation, each of the fields had developed a branched creek system and a varied geomorphological relief. Their habitat and species diversity proved to be equal to naturally grown mainland salt marshes.

Chondrichthyans are a very important taxon that plays a top predator role in the trophic level of the food web, and species are particularly vulnerable to exploitation in the marine ecosystem. The deep waters of the eastern Mediterranean Sea have been less studied than the continental shelf, especially for the chondrichthyans. Therefore, the present study was conducted to investigate the spatio-temporal distribution of chondrichthyans collected monthly in eight different (200–900 m) depth strata during different periods (2010–2011 and 2019–2021) using an otter bottom trawl. A total of 17 species were identified in upper bathyal, composed of 6 batoids, 10 sharks, and one chimaera. The constant species (dominance: DO% > 50) in the study area were Galeus melastomus, Scyliorhinus canicula, Etmopterus spinax, and Raja clavata. The most abundant species was E. spinax, followed by G. melastomus. Fourteen and 15 species were caught during the first and the second survey, respectively. Biodiversity characteristics (number of species, abundance, and diversity indices) varied only with bottom depth. Two different depthwise assemblages were estimated along the bottom depth gradient; ≤ 500 m and > 500 m. The discriminator species were R. clavata, S. canicula, G. melastomus, Dipturus oxyrinchus, and Squalus blainville found on the upper slope and E. spinax, G. melastomus, and Centrophorus cf. uyato found on the lower slope. With our results, total number of demersal chondrichthyan species found in the bottom (bathyal and continental shelf) of Antalya Bay was reached to 26 species.

The present study reports the occurrence of several specimens of the penaeid shrimp Penaeus notialis in the Gulf of Cadiz (Spain). The southern pink shrimp is a penaeid originating from east and west Atlantic tropical coastal waters. New observations of tropical species in temperate waters have increased in the last 20 years. This species may have been able to expand successfully northward to European waters, probably favored by global warming, although an accidental introduction by ballast waters cannot be completely discarded. The widespread presence of African biota such as P. notialis in the Gulf of Cadiz ecosystem underscores the necessity of establishing a long-term monitoring program that focuses on this and other currently established non-native species.

Abstract

A new species of the genus Lunovula Rosenberg, 1990, Lunovula supingae sp. nov. feeding on deep-sea hydroid Solanderia sp. (Solanderiidae, commonly known as tree hydroid) is described and illustrated from the East China Sea and South China Sea. It is most similar to Lunovula venusta Tsuchida & Kurozumi, 1999 in general shell shape but can be distinguished from the latter by having a more elevated funiculum with two large raised teeth, higher number of labial teeth, less protruding posterior extremity, and most notably, by having an outer lip that entirely thickens to the outside. This represents the first record of a pediculariid species feeding on a hydroid other than a hydrocoral. Phylogenetic analyses based on the COI and 16S rRNA genes using Bayesian inference and maximum likelihood showed that Lunovula supingae sp. nov. falls into the family Pediculariidae, supporting the systematic placement of Lunovula in the family. Furthermore, the phylogenetic analyses recovered the Ovulidae as polyphyletic, suggesting that this family needs a further taxonomic revision.

During the expedition of the NSCMB FEB RAS aboard the R/V Akademik M.A. Lavrentyev to the Koryak slope of the Bering Sea, Northwest Pacific (NWP) in 2018, three species of the family Caprellidae were collected in a seep activity zone at a depth of 658–662 m using a remotely operated vehicle (ROV) Comanche-18. Two morphospecies of the genus Caprella Lamarck, 1801 were represented by a few juveniles or damaged specimens. The species of the genus Liropus Mayer, 1890 sampled at three stations appeared to be new to science. The genus Liropus is known from the shelf and bathyal zones of tropical and low-boreal waters of the Atlantic and Pacific Oceans. Thus, L. beringi sp. nov., described herein, is the northernmost record of the genus. The new species can be identified by the following combination of features: absence of eyes, three-segmented pereopod 5, presence of two proximal projections on the palmar margin of gnathopod 2 with two grasping spines on each projection. Data on the NWP bathyal fauna of Caprellidae is summarized and discussed. A key to the bathyal species of Caprellidae from the NWP is provided.

Changing temperature and ocean acidification are well-recognised consequences of climate change in marine systems. In contrast to global trends, the South African west coast is experiencing cooling due to increased frequency and intensity of upwelling. The implications of concurrent cooling and acidification for marine biota are poorly understood, particularly at the community level. This laboratory study assessed how cooling and acidification might affect fouling communities along the South African west coast. Communities were experimentally exposed to two temperatures, 13℃ (current) and 9℃ (cooling), and three pH treatments, 7.9 (current), 7.6 and 7.4, for 18 days. Cooling and acidification altered community structure. Species diversity declined in response to acidification but was not affected by cooling. This was driven by greatest loss of species at 7.4 pH. Notably, acidification reduced the abundance of both calcifying and soft-bodied taxa, highlighting the vulnerability of taxa like ascidians to acidification. Overall, these results highlight the dominant threat posed by acidification, even for alien taxa that are often perceived as resilient to climate change. Additionally, in regions experiencing cooling, acidification may pose a greater threat to fouling communities than thermal changes.