Search Results (41)

Seafloor communities along the eastern Svalbard coast remain poorly studied. To address this gap, we sampled benthic organisms on the soft sediments of Storfjord in 2017 and 2019, a large fjord predominantly influenced by cold Arctic waters, to study the local fauna and identify the key environmental drivers shaping community structure. In total, 314 taxa were recorded, with an increase in abundance (from 3923 to 8977 ind. m⁻², mean 6090 ind. m⁻²) and a decline in biomass (ranging from 265 to 104 g m⁻², mean 188 g m⁻²) toward the outer part of the fjord. However, no clear spatial trends were observed for alpha diversity (approximately 100 species per 0.3 m²) or the Shannon index (mean 3 per station). The primary factors influencing benthic abundance were the duration of the ice-free period (IFP) and the degree of siltation (DS), both of which are proxies for trophic conditions. The prevailing taxa displayed a high tolerance to temperature fluctuations and seasonal variability in nutrient inputs. Benthic biomass showed a negative relationship with IFP, DS, and water depth, but it was positively correlated with the proportion of fine-grained sediment. The Yoldia hyperborea community (mean abundance: 3700 ind. m⁻², mean biomass: 227 g m⁻²) was associated with Arctic waters characterized by higher inorganic suspension loads. In contrast, areas with reduced or weaker sedimentation were dominated by the communities of Maldane sarsi (6212 ind m⁻², 226 g m⁻²) and Maldane sarsi + Nemertini g.sp. (5568 ind m⁻², 165 g m⁻²). The Spiochaetopterus typicus community (7824 ind m⁻², 139 g m⁻²) was observed in areas under moderate influence of Atlantic waters, characterized by low sedimentation rates and increased fresh detritus flux. Full article

Light pollution can have a variety of effects on aquatic organisms. Despite the fact that amphipods are one of the model organisms for studying the effects of light among macroinvertebrates, data on the reaction of Baikal amphipods to artificial lighting are limited and contradictory. In this study, we examine the response of Baikal littoral and sublittoral amphipod species to artificial lighting of varying intensity and spectral composition. In the experiments, amphipods were exposed to warm and white light at three different intensity ranges (5–15, 20–35, and 80–100 lx), as well as blue and red light. As a result, it was found that the reaction of Baikal amphipods to different lighting conditions was species-specific and dependent on the spectral composition of the light more so than the intensity of the light. In particular, white LED light generally repulsed E. cyaneus, but tended to attract A. godlevskii. P. cancelloides, and G. fasciatus, suggesting that white LED light may have a greater negative impact on wildlife than warm LED light. Generally, artificial light influences the behavior of Baikal amphipods, and an increase in light pollution on Lake Baikal may lead to changes in the littoral community in certain areas of the lake subject to pollution. Full article

The cartographic landscape analysis of Lake Doshne employs geographic landscape methods, GIS cartographic modeling, and geo-ecological analysis. This study includes hydrochemical analysis of the lake’s water mass, focusing on saline blocks, tropho-saprobiological indicators, and specific toxic action indicators. Three geological sections of anthropogenic and pre-Quaternary complexes, along with a geological–lithological transverse profile of the lake basin, were developed. Additionally, a geographical landscape model of the lake’s natural aquatic complex was presented, distinguishing littoral–sublittoral and profundal aquatic sub-tracts and five types of aquafacies with landscape metric assessments. This approach enables a comprehensive analysis and the creation of cartographic models that can serve as a basis for lake cadastre and optimization of the ecological and landscape conditions in local territories. Full article

Fucus spp. seaweeds thrive in the cold temperate waters of the northern hemisphere, specifically in the littoral and sublittoral regions along rocky shorelines. Moreover, they are known to be a rich source of bioactive compounds. This study explored the valorization of Fucus spiralis through the extraction of bioactives and polysaccharides (PSs) for food applications and biostimulant use. The bioactives were extracted using microwave hydrodiffusion and gravity (MHG), where the condition of 300 W for 20 min resulted in the highest total phenolic content and antioxidant activity of the extract. Cellular assays confirmed that the extract, at 0.5 mg/mL, was non-cytotoxic to HaCat cells. Polysaccharides (PSs) were extracted from the remaining biomass. The residue from this second extraction contained 1.5% protein and 13.35% carbohydrates. Additionally, the free amino acids and minerals profiles of both solid residues were determined. An edible film was formulated using alginate (2%), PS-rich Fucus spiralis extract (0.5%), and F. spiralis bioactive-rich extract (0.25%). The film demonstrated significant antioxidant properties, with ABTS and DPPH values of 221.460 ± 10.389 and 186.889 ± 36.062 µM TE/mg film, respectively. It also exhibited notable physical characteristics, including high water vapor permeability (11.15 ± 1.55 g.mm.m⁻².day⁻¹.kPa⁻¹) and 100% water solubility. The residues from both extractions of Fucus spiralis exhibited biostimulant (BS) effects on seed germination and seedling growth. BSs with PSs enhanced pea germination by 48%, while BSs without PSs increased the root dry weight of rice and tomato by 53% and up to 176%, respectively, as well as the shoot dry weight by up to 38% and up to 74%, respectively. These findings underscore the potential of Fucus spiralis within the framework of a circular economy, wherein both extracted bioactives and post-extraction by-products can be used for sustainable agriculture and food applications. Full article

This article is about the diversity of diatoms in the benthos of the upper sublittoral near Kazantip Cape, located on the shore of the Sea of Azov in the northeastern part of Crimea. The study was conducted in 2022 and 2023 at a depth of 0.1 to 1 m at temperatures from 3.7 °C to 29 °C and salinity from 13.6 to 15.6 psu on the following 11 species of macroalgae: Phaeophyta of Ericaria crinita, Gongolaria barbata, and Cladosiphon mediterraneus; Chlorophyta—Bryopsis hypnoides, Cladophora liniformis, Ulva intestinalis, and Ulva linza; and Rhodophyta—Callithamnion corymbosum, Ceramium arborescens, Polysiphonia denudata, and Pyropia leucosticta. A total of 97 taxa of Bacillariophyta belonging to 3 classes, 21 orders, 30 families, and 45 genera were found. The highest number of diatom species was found on U. linza (61 species), P. denudata (45), E. crinita (40), the lowest number was recorded on thalli P. leucosticta (9). On macroalgae were found of 80% benthic diatoms, 50% marine species, 36% brackish-marine, 9% freshwater, 5% brackish, and 36% cosmopolites. The maximum abundance of the diatom community was 243.4 × 10³ cells/cm² (P. denudata in September at 23.9 °C and 15.0 psu) with dominance by the diatom of Licmophora abbreviata, and the minimum was 3.8 × 10³ cells/cm² (P. leucosticta in January at 3.7 °C and 15.0 psu). The presence in the epiphyton of diatoms—indicators of moderate organic water pollution (32 species), which developed in masse in late summer—indicate a constant inflow of organic matter into the coastal waters of the Kazantip Cape. The bioindicator and statistical studies indicate the effectiveness of the conservation regime, especially at stations within the IUCN reserve, despite relatively high saprobity rates at stations exposed to recreational pressure and poorly treated domestic wastewater. Full article

Idunella spinifera (Dauvin and Gentil, 1983) (Crustacea: Amphipoda: Liljeborgiidae) is reported for the first time after the original description that was based on one immature female. Specimens were collected in the Ría de Muros (NW Iberian Peninsula) during the course of a study on macrofauna diversity in shallow sublittoral biogenic sands along a one-year period. The male and the ovigerous female are fully described, and the data on ecology and temporal variation of abundance is provided as well. Full article

Factors responsible for species distribution of benthic macroinvertebrates, including responses at different spatial scales, have been previously investigated. The aim of the present research was to review the most relevant factors explaining chironomid species distribution focusing on factors operating at different spatial scales, such as latitude, longitude, altitude, substrate, salinity, water temperature, current velocity, conductivity, acidity, dissolved oxygen, nutrient content etc. acting at regional levels and at a large or small water basin level. Data including chironomid species abundances from different lentic and lotic waters in Italy and other surrounding countries were analyzed using partial canonical correspondence analysis (pCCA) and multiple discriminant analysis (DISCR). Spatial analyses, including univariate Moran’s I correlograms, multivariate Mantel correlograms and Moran’s eigenvector maps (MEMs), were thereafter carried out. The results showed that habitat type, including different types of lotic waters (i.e., kryal, crenal, rhithral, potamal) and different lake types (i.e., littoral, sublittoral, profundal zones), is the most significant factor separating chironomid assemblages, while spatial factors act only as indirect influencers. Full article

This study assessed the taxonomic statuses of three lesser-known Magelona F. Müller, 1858 species collected from intertidal to sublittoral habitats in Korean coastal waters, basing identification on morphological features and comparing them with their closest congeners. We present a comprehensive description and illustration of taxonomically significant and standardized characters, covering all thoracic chaetigers of three newly discovered Magelona species from Korea. Within the documented Korean Magelona species, these three species exhibit the following distinctive characteristics. Magelona sachalinensis Buzhinskaja, 1985, possess diminutive superior dorsal lobes in the initial four chaetigers and specialized chaetae on chaetiger 9; Magelona lenticulata Gallardo, 1968, is characterized by foliaceous postchaetal superior dorsal lobes in chaetigers 1–8; and Magelona cf. longicornis Johnson, 1901, is distinguished by notably elongated noto- and neuropodial postchaetal lamellae on chaetiger 9. Methyl green staining patterns showed species-specific characteristics and were confirmed to be effective in distinguishing the examined Korean species from each other and useful for making comparisons with previously reported Magelona species. Our study suggests that further comprehensive research on the morphological and genetic characteristics of Magelona species will enhance our understanding of their diversity. Full article

The endemic Mediterranean bivalve Pinna nobilis is a typical example of an autogenic ecosystem engineer in sedimentary environments, as it modifies the substrate, creates new complex 3D habitats and concentrates various species, thus increasing local biodiversity. Despite the significant loss of P. nobilis populations due to the epidemic mass mortality that occurred in several regions of the Mediterranean, including the northern Adriatic Sea, the numerous empty shells, still firmly anchored in the sediment, may continue to play the role of basibiont of this species. The persistence of this ecological function was here investigated on dead specimens of P. nobilis through the structural and functional study of the associated epibenthic mollusc community. A large number of mollusc taxa, characteristic of both infralittoral and sublittoral hard and soft bottoms, were identified in thirteen shells collected from four different sites in the Gulf of Trieste. Multivariate analysis revealed a clear separation between sites in terms of taxonomic composition, species abundance and biomass, with differences in expressed functional traits. Overall, considerable taxonomic and functional diversity was found, suggesting that the empty shells continue to provide a suitable habitat for a variety of molluscs that are closely linked to the surrounding environment and fulfil many different ecological functions. Full article

Protists are key components of the microbial food web in marine pelagic systems because they link algal and bacterial production to higher trophic levels. However, their functioning and bathymetric distribution in benthic deep-sea ecosystems are still only poorly understood. However, biogeographical patterns of communities can be coupled to the functioning of ecosystems and are therefore important to understand ecological and evolutionary processes. In this study, we investigated the diversity and distribution of benthic protist communities from the sublittoral down to the deep seafloor (50–2000 m) around three islands of the Azores in the North Atlantic Ocean. Using amplicon sequencing of the V9 region (18S rDNA) of 21 samples, we found that protist community compositions from different depths were significantly different. Three assemblages were separated along the following depths: 50 m, 150–500 m and 1000–2000 m, which indicate that deep-sea areas surrounding islands might act as isolating barriers for benthic protist species. A limited gene flow between the communities could favor speciation processes, leading to the unique protist communities found at the different investigated islands. Full article

Many studies show that habitat complexity or habitat diversity plays a major role in biodiversity throughout different spatial scales: as structural heterogeneity increases, so does the number of available (micro-) habitats for the potential species inventory. The capability of housing species (even rare species) increases rapidly with increasing habitat heterogeneity. However, habitat complexity is not easy to measure in marine sublittoral sediments. In our study, we came up with a proposal to estimate sublittoral benthic habitat complexity using standard underwater video techniques. This tool was subsequently used to investigate the effect of habitat complexity on species richness in comparison to other environmental parameters in a marine protected area situated in the Fehmarn Belt, a narrow strait in the southwestern Baltic Sea. Our results show that species richness is significantly higher in heterogeneous substrates throughout all considered sediment types. Congruently, the presence of rare species increases with structural complexity. Our findings highlight the importance of the availability of microhabitats for benthic biodiversity as well as of the study area for regional ecosystem functioning. Full article

Two marine halacarids, Copidognathus levicostatus n. sp. and C. vicinus Bartsch, 1997, belonging to the C. gibbus group, have been recorded based on both sexes from the microhabitat of intertidal and sublittoral rocks on the coast of South Korea. Copidognathus levicostatus n. sp. Is characterized by a combination of features, as follows: the absence of areolae with rosette pores on all dorsal and ventral plates, the presence of a short frontal process, a pair of costae with raised narrow ribs on the posterior dorsal plate, the partial fusion of the anterior epimeral plate and genitoanal plate in both sexes, and three pairs of perigenital setae in the male. The Korean specimens of C. vicinus Bartsch, 1997 agree well with the original description from Hong Kong, except for the lateral claws bearing a comb. This study provides detailed (re)descriptions of the morphological characteristics of the two Korean halacarid species, C. levicostatus n. sp. and C. vicinus, based on illustrations and scanning electron microscope photomicrographs. Additionally, we present a dichotomous key for known Copidognathus species in Korean waters, accompanied by a brief comment on their occurrence in various microhabitats, especially their habitat preferences for geniculate and non-geniculate red coralline algae. Full article

The Far East of Russia is a region where boreal and tropical faunas mix; it is also a zone of cladoceran endemism. The present study aimed to compare a set of microcrustacean (Cladocera and Copepoda) associations in three large lakes of the Russian Far East: Khanka, Bolon, and Chukchagir. The associations of the microcrustaceans were identified based on the function of the discrete hypergeometric distribution. Many of the 108 taxa found here were unaffiliated with an association. Interestingly, the portion of taxa involved and “not involved” in species associations differed among geographic faunistic complexes. The rate of endemism was significantly higher among the taxa incorporated into the associations as compared to the “not involved” taxa. In all the lakes, there were large clusters of phytophilous species characteristic of the macrophyte zone (and its margins) and clusters characteristic of pelagic and sublittoral plankton. We found that in the three lakes, the microcrustaceans formed a set of functionally similar associations, but the taxonomic composition of each functional association was specific to each lake. We hypothesize that the composition of functional clusters reflects the history of colonization for each water body. That is, the founder effects and subsequent “monopolization” of habitats have affected species associations. Full article

An undescribed species belonging to the family Eunicidae was detected in a sublittoral habitat of the southern coast of Korea. This Korean eunicid species was initially thought to belong to the genus Lysidice based on its general appearance, including the absence of prostomial lateral palps and peristomial cirri. However, a more detailed characterization of the morphological features of the maxillae and mandible coupled with mtCOI and 18S rRNA gene sequence analyses confirmed that this species is a member of the genus Paucibranchia. The absence of lateral palps found in the intact adult specimens with 153 segments is a unique feature not previously reported in species belonging to Paucibranchia. Thus, the new species, Paucibranchia triantennata sp. nov., can be easily distinguished from other known congeneric species. Except for the absence of lateral palps, P. triantennata sp. nov. resembled P. conferta, P. gathofi, and P. patriciae in the shape of the prostomium, brief location and shape of branchiae, and absence of compound spinigers. However, P. triantennata could be clearly distinguished from these species by the shorter prostomial antennae, a large number of subacicular hooks, and the morphological features of the maxillae and compound falcigers. Full article

A new species, Robertgurneya jejuensis sp. nov., was described from sandy sediment samples collected at a depth of 25 m on Mun Island, Jeju, in June 2018. The new species is morphologically similar to Robertgurneya similis similis (Scott A., 1896) and Robertgurneya donghaensis Bang, 2021; this is the second record of the genus Robertgurneya in South Korea. The morphological characteristics of the similis group within the genus Robertgurneya, to which the new species is ascribed, are summarized here. Furthermore, an identification key is provided based on the summary. Molecular identification of the collected specimens, based on the nuclear 18S ribosomal RNA (18S rRNA) and the mitochondrial cytochrome oxidase subunit I fragment, was obtained. Finally, a phylogenetic tree was constructed to present the position of Robertgurneya within the Miraciidae family based on 18S rRNA sequences which is relatively conserved. As a result, the relationship with sister genera morphologically similar to Robertgurneya was also molecularly confirmed. Full article