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Two novel Gram-stain-negative, aerobic, and non-motile strains, designated FZY0004T and YYF002T, were isolated from an agar-degrading co-culture, which was obtained from seawater of the intertidal zone of Yancheng City, the Yellow Sea of China. Strain FZY0004T optimally grew at 28 °C, pH 7.0, and 2–6% NaCl, while strain YYF002T optimally grew at 28 °C, pH 7.5, and 2–4% NaCl. Strain FZY0004T possessed Q-9 as the major respiratory quinone, and its major fatty acids (> 10%) were summed feature 8 (C18:1ω7c), C16:0, and summed feature 3 (C16:1ω7c/C16:1ω6c). The polar lipids identified in strain FZY0004T were phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and several unidentified phospholipids (PL) and lipids (L). On the other hand, strain YYF002T had MK-6 as the predominant respiratory quinone and its major fatty acids consisted of iso-C15:0, iso-C15:1 G, and iso-C15:0 3-OH. The polar lipids identified in strain YYF002T were aminolipid (AL), PE, and several unidentified lipids. Strain FZY0004T shared 99.5% 16S rRNA gene sequence similarity and 90.1% average nucleotide identity (ANI) with T. povalilytica Zumi 95T, and strain YYF002T shared 99.2% 16S rRNA gene sequence similarity and 88.2% ANI with W. poriferorum JCM 12885T. The genomic DNA G + C contents of strains FZY0004T and YYF002T were 54.5% and 33.5%, respectively. The phylogenetic, phenotypic, and physiological characteristics permitted the distinction of the two strains from their neighbors, and we thus propose the names Thalassospira aquimaris sp. nov. (type strain FZY0004T = JCM 35895T = MCCC 1K08380T) and Winogradskyella marincola sp. nov. (type strain YYF002T = JCM 35950T = MCCC 1K08382T). [ABSTRACT FROM AUTHOR]

In this study, we reported a Gram-stain-negative, ovoid to rod-shaped, atrichous, and facultative anaerobe bacteria strain named YMD61T, which was isolated from the intertidal sediment of Yangma island, China. Growth of strain YMD61T occurred at 10.0–45.0 °C (optimum, 30.0 °C), pH 7.0–10.0 (optimum, 8.0) and with 0–3.0% (w/v) NaCl (optimum, 2.0%). Phylogenetic tree analysis based on 16 S rRNA gene or genomic sequence indicated that strain YMD61T belonged to the genus Fuscovulum and was closely related to Fuscovulum blasticum ATCC 33,485T (96.6% sequence similarity). Genomic analysis indicated that strain YMD61T contains a circular chromosome of 3,895,730 bp with DNA G + C content of 63.3%. The genomic functional analysis indicated that strain YMD61T is a novel sulfur-metabolizing bacteria, which is capable of fixing carbon through an autotrophic pathway by integrating the processes of photosynthesis and sulfur oxidation. The predominant respiratory quinone of YMD61T was ubiquinone-10 (Q-10). The polar lipids of YMD61T contained phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, five unidentified lipids, unidentified aminolipid and unidentified aminophospholipid. The major fatty acids of strain YMD61T contained C18:1ω7c 11-methyl and summed feature 8 (C18:1ω 7c or/and C18:1ω 6c). Phylogenetic, physiological, biochemical and morphological analyses suggested that strain YMD61T represents a novel species of the genus Fuscovulum, and the name Fuscovulum ytuae sp. nov. is proposed. The type strain is YMD61T (= MCCC 1K08483T = KCTC 43,537T). [ABSTRACT FROM AUTHOR]

The organic carbon sequestered by the world's mangrove forests plays a key role in the global carbon cycle and may be central to climate change mitigation. This is because mangroves typically exhibit high rates of net primary production and greater carbon sequestration capacity compared to terrestrial ecosystems. This study investigated the influence of selected soil physicochemical properties on the soil organic carbon (SOC) content of Rekawa mangrove forest, Sri Lanka. The effect of soil pH, salinity, conductivity, moisture content (%), bulk density, porosity, phosphate, and nitrate content on SOC was examined along an intertidal gradient. Results showed, SOC was positively correlated with salinity (r2= 0.74), conductivity (r2= 0.76), moisture content (r2= 0.76), porosity (r2= 0.92), and phosphate content (r2= 0.74) while SOC was negatively correlated with bulk density (r2= -0.92) across the entire intertidal zone. Generalised Linear Model (GLM) resolved SOC to be best predicted as a function of soil porosity and soil moisture content [Akaike Information Criterion (AIC): 142.04], with other soil properties modulating the results within some zones. Overall, the present study shows that specific consideration of soil physicochemical properties could allow improved estimates of total carbon stocks which are becoming increasingly important for carbon accounting and national inventories. [ABSTRACT FROM AUTHOR]

The report provides new data on Vaucheria vipera Blum, one of the rarest collected marine species. In 2023, V. vipera was discovered in the littoral zone of the Unskaya Inlet of the White Sea. The record is considered first in Russia and the Arctic Ocean. The study of the morphology of specimens from the White Sea allowed to expand the morphological range of the species in terms of the maximum dimensions of oogonia, oospores, and antheridia. The work also pays attention to the basal septa that separate short branches bearing the gametangia. Based on the morphology of the gametangia, it is proposed to transfer this species to the section Woroninia. [ABSTRACT FROM AUTHOR]

ABSTRACT Coastal algal reef ecosystems, which are formed by the skeletal carbonate of crustose coralline algae (CCA), provide vital habitats for a diverse range of marine organisms and serve as valuable archives of long‐term environmental data. Despite the importance of these reef ecosystems, there is currently a lack of available information regarding the accretion rates of CCA in subtropical intertidal zones in the Taoyuan algal reef. We measured the vertical accretion and horizontal growth of CCA cultured in two aquaculture tanks over a 9‐month period. The vertical accretion and horizontal growth rate of CCA was approximately 0.29–0.43 and 5.5 μm·day−1 (the extrapolated annual value is equivalent to 0.11–0.16 and 2.0 mm·year−1, respectively). Newly colonized CCA had faster horizontal growth of approximately 110 μm·day−1 (equivalent to 40.2 mm·year−1). These results highlight the slow and gradual process of algal reef ecosystem formation in the subtropical intertidal zones. The CCA had a faster lateral growth rate as seen in the newly settled CCA. These findings contribute to our understanding of the overall growth dynamics of CCA. [ABSTRACT FROM AUTHOR]

Intertidal mussels experience prolonged emersion during low tide, followed by rapid submergence cooling during high tide, causing temperature-induced stress responses. This study examined variations in heart rate to investigate the relationship between emerged and submerged thermal stress in Mediterranean mussels Mytilus galloprovincialis and brown mussels Perna perna from one site on a south coast warm-water coastline and two sites on a west coast cold-water coastline in South Africa. Gaping behaviour in air displayed by P. perna appears to contribute towards their survivability under warmer conditions, as their flatline temperature was higher as compared with M. galloprovincialis, which do not display gaping behaviour. Warm-water acclimatised mussels of both species appeared better able to survive higher temperatures than cold-water acclimatised mussels. However, both mussel species are possibly living at their upper thermal tolerance based on their sublethal Arrhenius breakpoint temperature (ABT). The values of ABT were higher while exposed to air than when submerged, revealing physiological mechanisms at work to cope with changes in the intertidal zone. [ABSTRACT FROM AUTHOR]

Fiddler crabs have been used as model organisms in many laboratory and field studies. In their natural environment, social interaction with other fiddler crabs (conspecific or heterospecific) is recurrent, but manipulative studies involving these crabs as models are often performed with isolated individuals. The isolation of an animal can interfere in the behaviors recorded as response variables. Thus, the aim of this study was to evaluate whether the presence of other individuals affects the performance of behaviors of fiddler crabs Leptuca uruguayensis. We tested two hypotheses in the field: (1) the visual stimulus of the crab assemblage affects the activity of male fiddler crabs; and (2) the presence of other conspecific affects the activity of male fiddler crabs depending on the sexes of the individuals present. We found the activities of L. uruguayensis males mediated by social interactions does not depend exclusively on visual stimuli. Physical interaction with other conspecifics of both sexes enables the perception of stimuli which can influence the waving behavior of L. uruguayensis males. We suggest that behavioral studies with this model should consider the presence of other individuals. Understanding the behavioral complexity of a model organism contributes to more robust experiments with greater control of interfering variables. [ABSTRACT FROM AUTHOR]

In coastal environments, eutrophication and ocean acidification both decrease pH, impacting the abiotic conditions experienced by marine life. Infaunal invertebrates are exposed to lower pH conditions than epifauna, as porewater pH is typically lower than the overlying water. We investigated the effects of altering sediment carbonate chemistry, through the addition of transplanted green algae and/or crushed shell hash, on an infaunal community. This factorial field experiment was conducted on an intertidal mudflat in the Bay of Fundy, New Brunswick, from July to September of 2020. After 1 month, sediment pH was increased across all depths (0.09 ± 0.03 pH units, or 0.84–2.5%) by the shell hash, but was not affected by the algae, while the multivariate community composition was impacted by an interaction between algae and experimental block (6.9% of variation) as well as shell hash treatment (2.7% of variation). After month 2, all responses to the treatments disappeared, likely due to tidal currents washing away some of the shell hash and algae, suggesting reapplication of the treatments is needed. Most of the variation in the community composition was explained by spatial variation in the treatment replicates among the treatment blocks (33.5% of variation). Despite the small effects of the experimental treatments on sediment carbonate chemistry, distance-based linear modeling indicated that sediment pH may be an important driver of variation in the infaunal community. Given the complexity of the processes driving sediment chemistry in coastal environments, further experiments exploring changing environmental conditions that drive infaunal marine community structure are required. [ABSTRACT FROM AUTHOR]

Labakkang Beach, Pangkajene Islands Regency has the characteristics of gently sloping coastal waters covered with various mangrove and seagrass communities. In general, seagrass is more commonly found in intertidal than subtidal areas, this is due to the depth reason. However, based on first observations, seagrass in Labakkang coastal waters thrives in subtidal areas and is less fertile in intertidal areas. The purpose of this study was to decide the differences in species, cover, and density of seagrass in intertidal and subtidal areas in the waters of Labakkang Beach, Pangkajene Islands Regency. This research was conducted in July 2021 with the method used, namely purposive sampling. Measurements of environmental parameters at the sampling location were carried out directly (in situ) including temperature, salinity, tides, depth, and current velocity, while turbidity, Total Organic Matter (TOM) analysis, and grain size of sediment were carried out tegakanirectly (ex-situ). The results of the average measurements of temperature, salinity, current velocity, depth, turbidity and TOM respectively show the range of 300C - 310C; 33.3‰ – 35.0‰; 0.07 m/s - 0.18 m/s (at high tide); 0.31 m - 1.32 m; 11.06 NTU - 29.04 NTU and 2.49 % - 5.39 %. The results of sediment analysis using Software Gradistat are 2 types of sediment, namely medium sand & fine sand and 2 types of sediment texture, namely Slightly Gravelly Sand and Slightly Gravelly Muddy Sand. The average percentage of seagrass cover at the intertidal station was 23.33 % while at the subtidal station it was 61.11% and only 2 species of seagrass were found, namely Enhalus acoroides and Halophila ovalis. The average density of seagrass at the intertidal station is 48.88 ind/m2 while at the subtidal station it is 86 ind/m2. The results of the Independent T-test analysis showed that there were significant differences in the cover and density of seagrass in the intertidal zone and subtidal zone in the coastal waters of Labakkang.

Background: The marine environment harbors high biodiversity; however, it is poorly understood. Nucleotide sequence data of all marine organisms should be accumulated before natural and/or anthropogenic environmental changes jeopardize the marine environment. In this study, we report a cost-effective and easy DNA barcoding method. This method can be readily adopted without using library preparation kits. It includes multiplex PCR of short targets, indexing PCR, and outsourcing to a sequencing service using the NovaSeq system. Methods and results: We targeted four mitochondrial genes [cytochrome c oxidase subunit I (COI), COIII, 16S rRNA (16S), and 12S rRNA (12S)] and three nuclear genes [18S rRNA (18S), 28S rRNA (28S), internal transcribed spacer 2 (ITS2)] in 95 marine invertebrate specimens, which were primarily annelids. The primers, including adapters and indices for NovaSeq sequencing, were newly designed. Two PCR runs were conducted. The 1st PCR amplified specific loci with universal primers and the 2nd added sequencing adapters and indices to the 1st PCR products. The gene sequences obtained from the FASTQ files were subjected to BLAST search and phylogenetic analyses. One run using 95 specimens yielded sequences averaging 2816 bp per specimen for a total length of six loci. Nuclear genes were more successfully assembled compared with mitochondrial genes. A weak but significantly negative correlation was observed between the average length of each locus and success rate of the assembly. Some of the sequences were almost identical to the sequences obtained from specimens collected far from Japan, indicating the presence of potentially invasive species identified for the first time. Conclusions: We obtained gene sequences efficiently using next-generation sequencing rather than Sanger sequencing. Although this method requires further optimization to increase the success rate for some loci, it is used as a first step to select specimens for further analyses by determining the specific loci of the targets. [ABSTRACT FROM AUTHOR]

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Saltwater‐freshwater mixing zones in beach aquifers support biogeochemical reactions that moderate chemical loads in fresh groundwater discharging to marine ecosystems. Existing laboratory and numerical modeling studies have demonstrated that fluid density gradients in the mixing zone can lead to free convection and the formation of density instabilities, or salt fingers, under a range of hydrologic, morphologic, and hydrogeologic conditions. However, salt fingers have rarely been observed in real‐world beach aquifers despite a growing body of field studies investigating intertidal mixing zones. In this study, we used geostatistical methods to generate randomly distributed assemblages of fine and medium sand and incorporated those geologic realizations into variable‐density variably‐saturated flow and salt transport simulations to explore the influence of geologic structure on mixing zone stability in tidally‐influenced beaches. Ensemble‐averaged model results show that geologic heterogeneity inhibits salt finger formation and promotes a stable intertidal mixing zone due to enhanced dispersion. This effect is highest for high degrees of heterogeneity and for more laterally connected geologic architecture. Compared to hydraulically equivalent homogeneous models, sediments with moderate to high heterogeneity produce mixing zones that are on average 19%–29% smaller and 3–10 times more stable due to the absence of the downward convection and seaward movement of salt fingers. The models indicate that geologic heterogeneity may explain the lack of field observations of salt fingers in real‐world intertidal mixing zones. The findings have implications for predicting the onset of free convection in beaches and for understanding intertidal pore water biogeochemistry and chemical fluxes to the ocean. Key Points: Geologic heterogeneity inhibits salt finger formation in beach aquifers and promotes a stable mixing zone due to enhanced dispersionIntertidal saltwater‐freshwater mixing zones are most stable under high degrees of heterogeneity and high geologic continuityResults provide a possible explanation into the lack of field observations of fingering flow in beach aquifers [ABSTRACT FROM AUTHOR]

Salt marshes are being lost worldwide even though they provide essential ecosystem services. Habitat classification of salt marshes based on fauna, which is an effective indicator of their ecosystems, is expected to be useful to effectively assess the baseline for conservation and restoration; however, it has not been well studied. This study aimed to identify the diversity of salt marsh sub-habitats for fauna, where biota was collected and the physicochemical environments were measured in 101 small patches of salt marsh (i.e., survey sites) across 32 temperate tidal rivers and inlets in Fukuoka Prefecture, Kyushu, Japan. A total of 78 aquatic animal species (decapod crustaceans, gastropod mollusks, bivalves, nereidid polychaetes, and fish) were observed, 63 of which were used as indicators for sub-habitat identification. Although reed plants covered 90 of the 101 survey sites, the survey sites were classified into six clusters based on fauna. Representative aquatic animals were identified in each cluster, and these six clusters had different physicochemical environments, such as salinity and sediment conditions. The results indicated that the six sub-habitats had different biotic and abiotic characteristics. On the other hand, the results of the ordination analysis indicated that the fauna of the six sub-habitats do not occur independently of each other but are composed of continuous and gradually changing fauna along environmental gradients. Although no significant differences in the areas of salt marsh patches among the clusters, species richness differed significantly, suggesting that physicochemical environments, such as salinity and sediment conditions, rather than spatial factors, may affect species diversity. The findings emphasize that each sub-habitat supports species diversity in temperate salt marshes and are expected to contribute to planning targets for future salt marsh conservation/restoration and further improvements in artificial marshes.

En las últimas décadas, se viene registrando en el Atlántico noreste un cada vez mayor número de citas de especies ictiológicas de aguas cálidas más meridionales. Diversos trabajos relacionan este fenómeno con el aumento de la temperatura de las costas europeas como consecuencia del calentamiento global. En este contexto, se documenta para el mar Cantábrico la primera cita de un ejemplar de góbido del género Zebrus de distribución principalmente mediterránea y con tan solo unas pocas citas en el océano Atlántico. ABSTRACT: In recent decades, an increasing number of records of ichthyological species from more southern warm waters have been recorded in the northeast Atlantic. Several studies relate this phenomenon to the increase in the temperature of European coasts as a consequence of global warming. In this context, here we document the first record for the Cantabrian sea of a specimen of a gobid fish belonging to Zebrus genus, which typically exhibit a Mediterranean distribution with only a few records in the Atlantic Ocean.

To understand the seasonal variations in shellfish community structure, the composition and diversity of shellfish in the intertidal zone of the Changshan Archipelago, China, were investigated. We investigated the composition and diversity of shellfish species in the intertidal zone (including NCD1, NCD2, BCD1, BCD2, TJD1, TJD2, DQD1, DQD2, NHD1, and NHD2) of five representative islands and 10 survey stations in the Changshan Archipelago during the low tide period in July and October 2021 and February and May 2022, and the water quality parameters of point water and interstitial water were analyzed. The results showed that the bottom material of the Changshan Archipelago was generally rock or gravel and the salinity fluctuated with the seasons. The salinity was high in summer and fall while low in spring and winter, with an average of 30.92±0.84. Compared with spring, summer, and fall, the temperature changed significantly in winter, with an average of (4.51±0.32) ℃ and the highest temperature being 23.48 ℃ during spring, summer, and fall. In general, the dissolved oxygen in the main islands of Changshan Archipelago (North and South Changshan Islands) was relatively low, with an average of (8.59±0.38) mg/L, while that in Tuoji Island, Daqin Island, and Nanhuangcheng Island was relatively high, with an average of (9.95±0.51) mg/L. A total of 12 species of shellfish were collected in this survey, including Crassostrea sp., Monodonta labio Linnaeus, Littorina brevicula, Mytilus galloprovincialis, Patelloida pygmaea, Chlorostoma rustica, Reishia clavigera, Thais luteostoma, Ocinebrellus inornata, Cellana toreuma, Ruditapes philippinarum, and Rapana venosa. The number of shellfish species in each season was the highest in spring, with an average of eight species, followed by in fall, with an average of six species. Winter had the least number of shellfish species collected, with an average of four species. In addition, the North and South Changshan Islands presented the most shellfish species at eight and nine species, respectively. The number of shellfish collected in DQD was the least (six species). There were differences in shellfish density at different survey sites, among which DQD2 had the highest density, with an average density of 41.26 ind./m2. The lowest density was in NCD2, and the average density was 13.71 ind./m2. In the same season, the shellfish density at different survey sites was different, the proportion of dominant species at different survey sites was also different. In spring, the density of Crassostrea sp., Cellana toreuma, and Chlorostoma rustica was high, while in summer, the density of Crassostrea sp., Mytilus galloprovincialis, Littorina brevicula, and Cellana toreuma was high. In fall, the density of Crassostrea sp., Littorina brevicula, and Mytilus galloprovincialis was the highest, while in winter, the density of Crassostrea sp., Patelloida pygmaea, and Cellana toreuma was the highest. The species diversity (H´) of shellfish in each tidal area of the survey site is shown as middle tidal zone (1.44) > low tidal zone (1.40) > high tidal zone (0.44). Overall, the average shellfish species diversity in the 10 survey sites was spring (1.26) > winter (1.21) > fall (1.11) > summer (0.95). The average evenness index of species (J´) in the 10 survey stations was 0.55, among which the evenness index of DQD2, NCD2, NHD2, and TJD1 shellfish was 0.67, 0.64, 0.64, and 0.55, respectively. The evenness index of shellfish in each tidal area of the survey site was in order of middle tidal zone (0.67) > low tidal zone (0.59) > high tidal zone (0.29). The seasonal change was not obvious. The average shellfish abundance at the survey site was 0.533, including 0.82, 0.68, 0.60, and 0.53 shellfish abundance at NCD2, NHD2, BCD2, and NCD1, respectively. The abundance index of shellfish in each tidal area of the survey site was in order of middle tidal zone (0.56) > low tidal zone (0.52) > high tidal zone (0.17). Overall, the average shellfish abundance in the 10 survey sites was spring (0.681) > fall (0.573) > summer (0.458) > winter (0.418). Seasons (temperatures) have the most obvious impact on the diversity and abundance of intertidal shellfish resources. Anthropogenic activities, such as aquaculture and tourism, also affect the distribution and quantity of shellfish species. The results of this study not only enrich the data of intertidal shellfish resources on islands in China but also provide basic information and reference for biodiversity and environmental protection of intertidal shellfish on the Changshan Islands.

For the management of estuaries and the preservation of tidal flats it is crucial to understand the tidal flat shape and development. Previous work focused predominantly on the quasi-equilibrium shape of tidal flats along open coasts with a dominant cross-shore flow and wave exposure. This paper evaluates the shape of fringing tidal flats in engineered estuaries, where longshore velocities generally dominate. Using a long-term (20 years) topographic data set of an anthropogenically modified estuary in the Netherlands (the Western Scheldt estuary), we relate key profile shape parameters and changes over time to natural and anthropogenic processes. In an engineered estuary, the tidal flat shape depends on the estuary geometry, hydrodynamic forcings and human interventions. In contrast to open coast tidal flats, the presence of the channel and dominant longshore flow determines the available cross-shore length (accommodation space) of the tidal flat and the shape of the tidal flat. This accommodation space defines the maximum tidal flat height and opportunity for marsh development. We propose the use of the Index of Development, indicating to what extend tidal flats have space to develop. This index is not only influenced by longshore and cross-shore flow, but also (or even more) by hydraulic structures, dike realignments and channel migration. Especially the latter two strongly influence the accommodation space and thereby the maximum tidal flat height and the opportunity for marsh development. For large stretches of the Western Scheldt, the accommodation space is too small, and the majority of the tidal flats do not vertically extent to mean high water. The success of tidal flat and marsh restoration projects depends on the accommodation space. [ABSTRACT FROM AUTHOR]

A new intertidal species of the melitid amphipod, Melita panda, from the Wakayama Prefecture, Japan, is identified and described. Melita panda sp. nov. differs from the similar M. koreana and M. nagatai by its black-and-white body color, well-developed anterodistal projection of the male gnathopod 1 propodus, and telson armature. Molecular phylogenetic analyses based on the nuclear 28S rRNA and mitochondrial COI genes support that M. panda sp. nov. is closely related to M. koreana and M. nagatai. [ABSTRACT FROM AUTHOR]

Tylorrhynchus osawai, nereidid polychaete that is considered to support estuarine biodiversity, undergoes a unique epitokous metamorphosis for reproductive swarming. The reproductive swarming of this species has been observed in Japan for more than 100 years; however, the benthic phase of this species has not been well researched. In this study, we aimed to elucidate the morphological allometry and life history, specifically the reproductive swarming, of this species. To accomplish this, surveys were conducted to collect atokes and epitokes from a tidal river in Kyushu, Japan. A total of 1670 T. osawai specimens were collected and preserved in 80% ethanol. The body widths of these specimens were measured, while several intact specimens underwent additional measurements of body length and the number of chaetigers. The morphological allometry of this species differed between atokous and epitokous forms, indicating that its heteronereis form might be suitable for migration from a tidal river to the ocean. The survey results pertaining to the benthic phase of this species indicated that its lifespan was approximately one year or longer. In addition, the settlement, growth, and maturity of this species exhibited a degree of plasticity, potentially influenced by habitat landscapes and sediment conditions. Based on the surveys conducted on reproductive swarming, climate change could have caused the peak of reproductive swarming to shift slightly later than that of several historical observations. Our findings contribute to elucidating the ecological significance of epitokous metamorphosis in nereidid polychaetes and to conserving T. osawai populations. [ABSTRACT FROM AUTHOR]

Based on the existing deep soft soil geological conditions in beach area, greater challenges were brought to the construction of cast-in-place box girders. Relying on the first phase project of Shiyitang Expressway in Zhejiang Province, the influence of artificially solidified hard shell layer on bridge pile foundation under preloading load was studied. Based on the soil hardening model, a three-dimensional numerical calculation model was established. The variation law of axial force, lateral friction resistance and horizontal displacement of pile body under different depth of hard shell was compared. The results show that when the thickness of the hard shell is 2 m, the axial force of the pile is reduced by about 16% . The thickness of the hard shell layer will change the transfer depth of the negative friction resistance, which shows that the thicker the thickness of the hard shell layer, the more the neutral point of the pile side resistance moves up. In addition, in a certain depth influence range, the hard shell layer can effectively control the horizontal displacement of the pile top and the pile body at different depths. The larger the thickness of the hard shell layer, the smaller the horizontal displacement of the pile top. Finally, the influence of soil modulus on the horizontal displacement of the pile was analyzed. It is found that the horizontal displacement of the pile will decrease with the increase of the compression modulus of the soil, and the influence of soil unloading / reloading stiffness modulus Eur is higher than that of soil deflection loading stiffness modulus E50 and lateral compression stiffness modulus of soil Eeod . [ABSTRACT FROM AUTHOR]

Knowledge of fish movement ecology contributes to the improvement of fishery resource management actions. We investigated the horizontal movement of the black sea bream Acanthopagrus schlegelii around the natural coast of Nishinoumishima Island in Hiroshima Bay, using active acoustic tracking. Six adult fish equipped with depth transmitters were tracked for a total of 54 days in the bay. Five tagged fish were fully tracked for 9–10 consecutive days after release. Tagged fish were found in the intertidal zone and adjacent subtidal zones, which were shallower than 12 m, and within 170 m off the coastline. The mean daily movement distance and 95% kernel utilized density of tagged fish were 191 ± 272 m and 60,207 ± 99,437 m2, respectively. The swimming depth of the tagged fish was 1–4 m above the seafloor. We opine that the littoral area (< 12 m in depth), which includes the intertidal zone and adjacent subtidal zone, is an important habitat for black sea bream. [ABSTRACT FROM AUTHOR]

The research progress of benthic diatoms on sandy beach at home and abroad was reviewed in this paper. As the main flora of sandy beach, benthic diatoms adapted to the changeable sandy environment through a series of mechanisms. In the sediments of the intertidal zone, benthic diatoms were an important part of primary productivity and beach food webs. Sediment, temperature, salinity, light, nutrients and biological factors all affected the growth and community distribution of benthic diatoms. In recent years, there had been studies on the distribution characteristics of benthic diatom communities in the intertidal zone of China, but generally speaking, there were relatively few studies on benthic diatoms in sandy environment, and further investigation is needed to improve the study of diatom ecology in China. [ABSTRACT FROM AUTHOR]

The presence of microplastics in tidal sediments is a growing ecotoxicological concern for sea and benthic health. This investigation was designed to record and characterize the vertical prevalence of microplastics (MPs) in intertidal sediments of the Persian Gulf (around Bushehr city, Iran). Sediments of three depths (0-10 cm, 10-20 cm, and 20-30 cm) were sampled during low tide in six sites along the coastal zone of Bushehr, Iran. MP particles were found in all evaluated areas and sediment depths. The average abundance of MPs in all of the sediment samples was 117.96 ± 97.75 particles kg−1 dry sediment. No differences were found in the MPs number among the sites. The most dominant microplastics in surface sediments were 2-5 mm in size. In all areas, fibers and fragments were more abundant. Particles in higher depths (0-10 cm) were often colorless (white, and transparent). Raman spectroscopy indicated the presence of polystyrene, polyethylene, polyvinyl chloride, polyethylene terephthalate, and polypropylene in the samples. Further research is required to evaluate the possible interaction between MPs and layers of sediments. Waste management and proper wastewater disposal are critical to control MPs pollution in intertidal ecosystems around coastal cities.

With the growing global focus on marine environmental conservation and management, it is imperative to evaluate the ecological quality of marine ecosystems accurately. In this study, we employed seven biotic indices, namely the AZTI marine biotic index (AMBI), BENTIX, benthic opportunistic polychaetes amphipods index (BOPA), benthic pollution index (BPI), multivariate AZTI marine biotic index (M-AMBI), abundance biomass comparison (W-value), and Shannon diversity index (H'), to assess the benthic ecological quality in the intertidal zone of Cheonsu Bay, South Korea. Except for the H' and W-value, the indices (AMBI, BENTIX, BOPA, BPI, and M-AMBI) suggest that the ecological quality at most stations in the intertidal zone of Cheonsu Bay was acceptable. Furthermore, the influx of a large amount of eutrophic freshwater has impacted the intertidal zone of Cheonsu Bay, but the applicability of the seven biotic indices requires further investigation. [ABSTRACT FROM AUTHOR]

Spatial changes in environmental characteristics strongly influence the structure of benthic communities on sandy beaches, where the patterns of occurrence are mainly controlled by morphodynamic characters and biological interactions. Despite being very abundant and extensive, the Amazonian sandy beaches are among the coastal environments less well known to science. On these beaches, the ghost shrimp Lepidophthalmus siriboia Felder and Rodrigues, 1993 is an important component of the intertidal macrofauna. The present study describes the small-scale distribution patterns of L. siriboia and of the macrobenthic communities in a dissipative macrotidal Amazonian sandy beach. Samples were collected in the intertidal zone of two areas: Area 1, next to a tidal channel; and Area 2, away from the tidal channel. In Area 1, with finer sediments, there was a higher burrow density of L. siriboia and higher density and species richness of macrofauna. In both areas, the burrow density of L. siriboia increased towards the sea. The faunal distribution patterns can be explained by changes in flooding and the type of substratum across the shore and alongshore. These findings add to our knowledge of tropical sandy beach ecology and reinforce the idea that tropical macrotidal beaches have a complexity of morphological features, which are drivers of macrofaunal structure. [ABSTRACT FROM AUTHOR]

Marine worms of the family Serpulidae (Annelida) construct calcareous tubes that adhere to hard substrata. The tubes of the Spirobranchus kraussii complex have a flat projection, known as a 'flap', over the opening of the tube. In the present study, we examined the reconstruction growth rates of the flap of Spirobranchus akitsushima after artificial removal, compared with the normal growth rates (control), for approximately a month at a study site in Shirahama, Wakayama, Japan. Although the difference in the length of the flap on day 8 compared with the original length (before the removal treatment) was significant in the treatment group, the differences became nonsignificant after day 13. The flap growth rate was found to be higher than the growth rates of the tubes of other serpulid species, including Spirobranchus sp. 5 sensu Kobayashi & Goto (2021) of the S. kraussii complex, as reported in previous studies. In contrast, the length of the flap in the control group did not differ significantly during the survey period. These results indicate that the flap is more quickly reconstructed after removal compared with growth under normal conditions. Our findings imply that the flap may be of importance for the survival of S. akitsushima. [ABSTRACT FROM AUTHOR]

The population structure and somatic condition of intertidal gastropods can be affected by the degree of exposure to waves on rocky coasts. We studied the influence of wave exposure and climatic temporality on the sizes and somatic condition of two species of intertidal neogastropods (Plicopurpura patula and Vasula deltoidea), at different sites within the coastal strip of Santa Marta, Colombian Caribbean. The study was conducted in two areas, Santa Marta Bay and Tayrona National Natural Park, where four collection stations were established. The study was carried out from 2015 to 2017 with eight sampling campaigns. Shell size, weight, biofouling proportion, condition index, and wave exposure index were determined. Only in P. patula was there a direct and significant relationship between the level of exposure to waves and sizes (p = 0.011, r2 = 0.683). Significant variation in the condition index occurred in V. deltoidea when specimens collected from the upper intertidal exceeded the values of those extracted from the supratidal up to two meters depth. Wave exposure affects the species P. patula, which is found in the supralittoral zones, presenting larger sizes in the sites with greater wave exposure. [ABSTRACT FROM AUTHOR]

Illustrated descriptions and differential diagnoses of four new species of psammophilous microturbellaria from the genera Coulterella Timoshkin 2004, Cohenella Timoshkin 2004, and Linella Timoshkin 2004 (Kalyptorhynchia, Rhynchokarlingiidae) inhabiting the intertidal zone of Lake Baikal are provided. Short notes on their ecology and distribution are presented. All species have been found in sandy soil at a depth of 1.5–3 m and represent a part of the psammophilic communities of the lake. [ABSTRACT FROM AUTHOR]

Information concerning the allometric growth of the bivalve mollusk (Mya arenaria) populations in the intertidal zones of Zelenetskaya and Yarnyshnaya inlets, Barents Sea, is presented. The population density in Zelenetskaya Inlet averages 40 ind./m2 and the biomass is 280 g/m2 versus 62.6 ind./m2 and 142 g/m2 in Yarnyshnaya Inlet, respectively. A detailed analysis of the granulometric composition of bottom sediments of the intertidal zone and the content of organic matter are determined for the first time. The study areas are found to differ in the composition of bottom sediments. The organic matter in Zelenetskaya Inlet averages 0.8% versus 2.2% in Yarnyshnaya Inlet. Shell formation is determined by adaptations to living conditions, also reflecting the different size and age structure of M. arenaria populations. Among the mollusks of older age groups, the shell grows allometrically, following the principle of weak negative allometry versus isometrically among young individuals. [ABSTRACT FROM AUTHOR]

A commercial fishery for the Cape rock oyster Striostrea margaritacea along the north coast of KwaZulu-Natal, South Africa (western Indian Ocean), follows a 4-year rotational cycle, with each harvest year followed by 3 fallow years across four harvest zones. We analysed reported harvesting effort and catch information, and fishery-independent oyster size composition data collected over 18 years (Feb 2003-Feb 2020), to investigate the sustainability of rotational harvesting. Total harvesting effort and catches declined over the study period, but on average, the number of oysters collected per outing increased. Fewer outings in recent years were attributed to incomplete reporting and a progressive loss of access to harvest sites. Generalised linear mixed models were used to estimate trends in oyster mean size in relation to fishing method (divers and intertidal collectors), harvest zone, 4-year rotational cycles, and months spent in a zone. Oyster mean size increased from north to south along the coast. Oysters caught by divers on newly exploited deeper reefs were initially larger than those caught by intertidal collectors. Mean oyster size decreased monthly during 1-year harvest periods but recovered to pre-harvest size over 3 fallow years. The results confirmed that the current rotational harvest strategy is well-suited to oyster biology and is sustainable at the present level of effort. Improved reporting on harvesting effort and catch are required to verify longer-term spatiotemporal trends in this fishery. More effective stakeholder communication is needed to resolve potential user conflict [ABSTRACT FROM AUTHOR]

A barred tidal flat has grown in the north of Subarnarekha river estuarine system along the western coast of Bay of Bengal, Talsari, Odisha, over the last twenty years, from 2002 to 2022. The channels form an integral part of the tidal flat and act as conduits for supplying and draining sediments with flood and ebb flows. Multiple drainage basins with quantifiably different channel patterns are identified within the Talsari tidal flat. Two major types of tidal channels, namely through-flowing and dead-end channels, are recognized in the Talsari Tidal flat. Channel morphometric analysis reveals that the sand:mud ratio in the tidal flat sediments, along with slope, tidal range, current strength, vegetation cover and climate, strongly controls the channel pattern evolution in drainage basins within the tidal flat. Channel migration and filling patterns develop distinctly different sedimentary bodies with respect to laterally adjacent flat areas. High-energy climatic storms played an important role in transporting silty-muddy sediments to the tidal flat and also brought changes in channel morphometry along with the development of regionally developed scours. [ABSTRACT FROM AUTHOR]

Lagoa do Peixe National Park (LP), in southern Brazil, is an important staging site for Red Knots (Calidris canutus rufa), especially during autumn migration. We describe the diet of Red Knots in LP by analyzing droppings and compare these findings with prey availability onsite. We collected droppings on a stretch of oceanic beach within LP in March and April 2006. We identified undigested prey items in 71 droppings, 32 collected in March and 39 in April. As expected, Red Knots at LP fed on abundant local benthic invertebrates. Beetles were present in almost all (95.7%) droppings. Other frequent items were mole crabs (Emerita brasiliensis), yellow clams (Mesodesma mactroides), and Argentinean wedge clams (Donax hanleyanus). The most abundant invertebrates in the lagoon were polychaetes and mud snails (Heleobia australis). On the beach, the most abundant invertebrates were polychaetes, isopods, and amphipods; however, mole crabs, yellow clams, and Argentinean wedge clams were also present in significant numbers. Prey availability coincides with Red Knot northward migration from Argentina: from January to April, small juvenile yellow and Argentinean wedge clams and mole crabs reach their highest quantities at LP. The high frequency of beetles in droppings was unexpected since nonbreeding Red Knots consume insects infrequently. According to the literature, beetles are the dominant benthic organisms on the backshore of beaches in southern Brazil. We speculate these insects are trapped by incoming tides, washed ashore, and captured by knots on the shoreline. O Parque Nacional da Lagoa do Peixe (LP), no sul do Brasil, é um importante local de parada para maçaricosde-peito-vermelho (Calidris canutus rufa), especialmente durante a migração de outono. Descrevemos a dieta do maçarico-de-peito-vermelho na LP por meio da análise de excrementos e comparamos esses resultados com a disponibilidade de presas no local. Coletamos fezes das aves em um trecho de praia oceânica na LP em março e abril de 2006. Identificamos partes não digeridas de presas em 71 excrementos, 32 coletados em março e 39 em abril. Como esperado, os maçaricos-de-peito-vermelho na LP se alimentaram de invertebrados bentônicos abundantes no local. Besouros estavam presentes em quase todos (95,7%) excrementos. As outras presas mais frequentes foram tatuíras (Emerita brasiliensis), mariscos-brancos (Mesodesma mactroides) e moçambiques (Donax hanleyanus). Os invertebrados mais abundantes na lagoa foram poliquetas e o gastrópode (Heleobia australis). Na praia, os invertebrados mais abundantes foram poliquetas, isópodes e anfípodes; no entanto, tatuíras, moluscos-brancos e moçambiques estavam presentes em números significativos. A disponibilidade de presas coincide com a migração para o norte dos maçaricos-de-peito-vermelho vindos da Argentina: de janeiro a abril, pequenos juvenis de mariscos-brancos e moçambiques e tatuíras atingem suas maiores quantidades na LP. A alta frequência de besouros nos excrementos foi inesperada, porque maçaricos-de-peito-vermelho consomem insetos infrequentemente durante o período não reprodutivo. Segundo a literatura, besouros são os organismos bentônicos dominantes no supralitoral de praias no sul do Brasil. Especulamos que esses insetos sejam capturados pela maré alta e levados até a zona entre marés e então consumidos pelos maçaricos-de-peito-vermelho. [ABSTRACT FROM AUTHOR]

In this study, we reported a Gram-stain-negative, rod-shaped, atrichous, and aerobic bacterial strain named YMD87T, which was isolated from the intertidal zone sediment of Chinese Yellow Sea. Growth of strain YMD87T occurred at 10.0–40.0 °C (optimum, 25–30 °C), pH 4.0–12.0 (optimum, 8.0) and with 0–6.0% (w/v) NaCl (optimum, 0.0–2.0%). Phylogenetic tree analysis based on 16S rRNA gene sequence indicated that strain YMD87T belonged to the genus Tropicibacter and was closely related to Tropicibacter alexandrii LMIT003T (97.2% sequence similarity). Genomic analysis indicated that strain YMD87T contains a circular chromosome of 3,932,460 bp with G + C content of 63.8% and three circular plasmids of 116,492 bp, 49,209 bp and 49,673 bp, with G + C content of 64.3%. Genomic functional analysis revealed that strain YMD87T is potential a novel sulfur-metabolizing bacteria. The predominant respiratory quinone of YMD87T was ubiquinone-10 (Q-10). The major polar lipids of YMD87T contained phosphatidylglycerol, phosphatidylethanolamine, five unidentified lipids, five unidentified phospholipids, phosphatidylcholine, unidentified glycolipid and five unidentified aminolipids. The major fatty acids of strain YMD87T contained C12:1 3-OH, C16:0, and summed feature 8 (C18:1 ω7c or/and C18:1 ω6c). Phylogenetic, physiological, biochemical and morphological analyses suggested that strain YMD87T represents a novel species of the genus Tropicibacter, and the name Tropicibacter oceani sp. nov is proposed. The type strain is YMD87T (= MCCC 1K08473T = KCTC 92856 T). [ABSTRACT FROM AUTHOR]

For the management of estuaries and the preservation of tidal flats it is crucial to understand the tidal flat shape and development. Previous work focused predominantly on the quasi-equilibrium shape of tidal flats along open coasts with a dominant cross-shore flow and wave exposure. This paper evaluates the shape of fringing tidal flats in engineered estuaries, where longshore velocities generally dominate. Using a long-term (20 years) topographic data set of an anthropogenically modified estuary in the Netherlands (the Western Scheldt estuary), we relate key profile shape parameters and changes over time to natural and anthropogenic processes. In an engineered estuary, the tidal flat shape depends on the estuary geometry, hydrodynamic forcings and human interventions. In contrast to open coast tidal flats, the presence of the channel and dominant longshore flow determines the available cross-shore length (accommodation space) of the tidal flat and the shape of the tidal flat. This accommodation space defines the maximum tidal flat height and opportunity for marsh development. We propose the use of the Index of Development, indicating to what extend tidal flats have space to develop. This index is not only influenced by longshore and cross-shore flow, but also (or even more) by hydraulic structures, dike realignments and channel migration. Especially the latter two strongly influence the accommodation space and thereby the maximum tidal flat height and the opportunity for marsh development. For large stretches of the Western Scheldt, the accommodation space is too small, and the majority of the tidal flats do not vertically extent to mean high water. The success of tidal flat and marsh restoration projects depends on the accommodation space.

Based on the survey data in July 2020, the paper investigated the distribution characteristics and species diversity of the intertidal macrobenthic community in the Shankou Mangrove Reserve. A total of 52 species of macrobenthic animals in 7 phyla and 9 orders were recorded in this survey, mainly arthropods and mollusks. Chasmagnathus convexus, Paracleistostoma depressum, Gelonia coaxans, etc. were ranked as the top ten dominant species in the area. The average biomass and average density of macrobenthos were 81.17 g/m2 and 54 ind/m2, with Arthropods accounting for 43.70% and 80.09% of the total. Arthropods contributed the most to the community density. The diversity index of the macrobenthic community ranged from 0.86 to 2.52. Cluster analysis and multidimensional scale analysis could classify the communities into 3 types. Species diversity levels of the intertidal macrobenthic community in the Shankou Mangrove Reserve were low compared with other mangrove areas in China.

To scientifically analyze the effect of offshore wind farm on intertidal beach stability, this paper summarized the research progress of intertidal zone dynamic change analysis at home and abroad. The method of hypothetical sandbank surface discrimination (HSSD) was proposed. The topographic changes that caused by offshore wind turbine construction in intertidal zone were estimated quantitatively from single phase DEM, the contribution rate and contribution mode of the erosion and deposition change of offshore sand body terrain offshore caused by wind turbine construction and operation were analyzed. The multi temporal intertidal zone DEM was based on enhanced waterline method (EWM). It carried out the quantitative assessment of the safety and stability of offshore wind turbines due to the change of intertidal tidal flat erosion and deposition. The practical application proved that the scheme could be used for the influence of offshore wind turbines on intertidal zone topographic changes with quantitative remote sensing monitoring.

This article discusses a study conducted in Diu, Gujarat, India, which examined the community structure of marine macrofauna in the rocky intertidal zone. The study identified 70 species of macrofauna, with the highest diversity observed in the phylum Mollusca. The text emphasizes the importance of protecting the diverse marine habitats in Diu and calls for further research on the ecology and conservation of the region's unique marine biodiversity. The article also mentions other studies conducted in the Gulf of Kutch and Gulf of Khambhat regions, highlighting the higher diversity found in the rocky intertidal zone of the Saurashtra coast. [Extracted from the article]

This article discusses the distribution patterns of key gastropod species along the intertidal zone of the Adri Coast in the Kathiawar Peninsula, India. The study focused on five gastropod species and examined their preferences for different microhabitats such as rocks, puddles, crevices, and substrata. The results showed that each species had distinct preferences for specific intertidal microhabitats. The article also provides information on the physico-chemical parameters of the seawater and the ecological attributes of the studied gastropod species.The article discusses the distribution and abundance of key gastropod species along the rocky intertidal zone of the Adri coast in Gujarat, India. The study found that the abundance of these species varied throughout the year, with the highest abundance reported in January. The species showed clump distribution and their dispersion was not uniform. The study also examined the correlation between the gastropods and abiotic parameters such as temperature, pH, and salinity, and found that salinity had a positive effect on the distribution and density of the species. The results of the study highlight the importance of microscale habitats and conditions in maintaining gastropod populations.The document is a list of references cited in a research paper or article on the natural history and ecology of various marine gastropods and other invertebrates in the Gujarat region of India. The references include studies on population dynamics, habitat preferences, and diversity of different species, as well as taxonomic classifications [Extracted from the article]

Globally, there is a recognized need for widespread restoration of coastal wetlands. Despite this recognition, progress in many places has been slow, for reasons including legal and policy barriers. In Australia many of these legal barriers have been overcome in the development of the Carbon Credits (Carbon Farming Initiative ‐ Tidal Restoration of Blue Carbon Ecosystems) Methodology Determination 2022, which allows for certain coastal restoration projects to be accredited and ultimately receive Australian Carbon Credit Units. This paper describes the new methodology, outlines the key legal barriers which had to be addressed in its development, and analyzes the legal solutions utilized. It concludes with some general observations for fucoastal wetland restoration projects. Despite the jurisdictional focus on Australia, it is anticipated that these lessons will be of broader relevance to other countries grappling with restoration projects in the intertidal zone. [ABSTRACT FROM AUTHOR]

Background: The mitochondrial genomes (mitogenomes) of the family Serpulidae are characterized by a high nucleotide sequence divergence and a significant number of gene order rearrangements compared with other families within the phylum Annelida. However, only two of 50 genera of serpulids have mitogenomes already sequenced. In this study, we report the first sequencing and assembly of the complete mitogenome of Ficopomatus, thus providing further knowledge on mitochondrial gene sequences of Serpulidae. Methods and results: A mitogenome of the invasive reef-building polychaete Ficopomatus enigmaticus was amplified by long PCR and sequenced using the Illumina MiSeq System. It comprised 15,853 bp and consisted of 12 protein-coding genes (atp8 was not found), 23 tRNA, and two rRNA genes. The AT and GC skew values were infrequent when compared to annelid mitogenomes but similar to other serpulids sequenced to date (i.e., Spirobranchus and Hydroides). The mitochondrial gene order of F. enigmaticus was highly rearranged compared to other serpulids. To amplify 16S rRNA gene sequences, we developed a 16S rRNA primer set by modifying the universal primer set 16SarL/16SbrH. We detected the 16S rRNA sequence of F. enigmaticus deposited in GenBank erroneously characterized as of serpulid origin. We reported for the first time the presence of two lineages of F. enigmaticus in Japan, which have already been identified in California, Australia, and the Mediterranean. Conclusions: The first mitochondrial genome of F. enigmaticus showed a unique gene order rearrangement, corroborating the remarkable diversity in the previously reported mitogenomes of other serpulid species. The presence of the two lineages of F. enigmaticus identified for the first time in Japan represents another case of cryptic invasion. The first 16S rRNA gene sequences of F. enigmaticus obtained in the present study can be used as reference sequences in future DNA metabarcoding studies. [ABSTRACT FROM AUTHOR]

Abstract Bacterial communities play pivotal roles in nutrient cycling in mangrove forests. The assembly of mangrove microbial communities has been found to be influenced by complex factors, such as geographic distance, physicochemical conditions, and plant identity, but the relative importance of these factors and how these factors shape the assembling process remain elusive. We analyzed the bacterial communities sampled from three mangrove species (Aegiceras corniculatum, Bruguiera sexangula, and Kandelia obovata) at three locations along the estuarine Dongzhai Harbor in Hainan, China. We revealed larger differences in rhizosphere bacterial communities among geographical locations than among plant species, indicated by differences in diversity, composition, and interaction networks. We found that dispersal limitation and homogeneous selection have substantial contributions to the assembly of mangrove rhizosphere bacterial communities in all three locations. Following the phylogenetic‐bin‐based null model analysis (iCAMP) framework, we also found dispersal limitation and homogeneous selection showing dominance in some bins. The greater differences among geographic locations may be mainly attributed to the larger proportions of dispersal limitation even at such a short geographic distance. We also found that beta diversity was positively correlated with environmental distances, implying that the more similar environmental conditions (such as rich carbon and nitrogen contents) among plant species may have shaped similar bacterial communities. We concluded that the geographic distances, which are associated with dispersal limitation, played a key role in assembling mangrove rhizosphere bacterial communities, while physicochemical conditions and plant identity contributed less.

Ridge‐and‐runnel systems are common morphological features across the intertidal zone of dissipative macrotidal beaches. However, these systems have often been overlooked by macrofaunal zonation studies. The present study investigated the effects of this system on the spatial distribution of the macrofaunal community on an Amazonian macrotidal sandy beach. Samples (macrobenthos and sediments) were collected at seven equidistant levels (50 m apart) from the high tide water mark to the swash zone, in two different areas: (1) with and (2) without ridge‐and‐runnel systems. The results showed a significant increase in macrofaunal abundance and richness in area with runnels, associated with muddier sediment and higher organic content. The macrofauna in the runnels, both in upper‐intertidal and lower‐intertidal zones, had higher density and richness than that in the sandbars. There was no difference between tidal levels in area 2, although we observed an increasing tendency of abundance and richness towards the low tide line. Taxonomic composition and trophic groups also differed between areas, with predominance of species that are typical of sandy‐mud substrate and higher participation of nonselective deposit feeders in area 1. Predatory species typical of sandy substrates prevailed in area 2. These findings add knowledge to sandy beach ecology and indicate the importance of including aspects of habitat complexity in both across‐ and alongshore macrofaunal distribution studies. [ABSTRACT FROM AUTHOR]

Nglolang Beach, which is located at Sepanjang, Kemadang, Tanjungsari, Gunungkidul regency, Daerah Istimewa Yogyakarta, Indonesia, has a macroalgae ecosystem. Macrolaga can be found in the intertidal zone, which is between marine and terrestrial areas. Substrate characters in the intertidal zone consist of sand, rocks, and dead coral. The growth of macroalgae is generally influenced by several factors such as substrate and environmental parameters. The growth of tourism activity in Gunungkidul has made Nglolang Beach a destination that attracts the attention of tourists. This research aims to study the abundance of macroalgae in the intertidal zone and the environmental factors that influence abundance of macroalgae at Nglolang Beach. The research was carried out using stratified systematic sampling method utilizing 1×1 m² sized plot in the intertidal zone. In addition, an analysis of ecological parameters such as water temperature, air temperature, salinity and water pH were carried out. After observation, the density (Ds), frequency (F), dominance (D), relative density (RD), relative frequency (RF), relative dominance (RDo) and Species important values index (IVI) were calculated. Based on the important value index (IVI), the highest abundance belongs to the species Ulva lactuca (IVI = 93.84; RD = 36.28%; RF = 21.28%; RDo = 36.28%), meanwhile the lowest belongs to the species Chaetomorpha crassa (IVI = 1.21; RD = 0.08%; RF = 1.06%; RDo = 0.08%). [ABSTRACT FROM AUTHOR]

In the present work, the morphological characteristics of sagitta were described and analysed for 10 species of combtooth blennies (Blenniidae) inhabiting the intertidal region of the Persian Gulf and Makran zone of Oman Sea to see the taxonomic usefulness of otoliths, especially their hidden characters for species identification. Based on the obtained results, sagitta morphology could be considered as diagnostic characters distinguishing the genera Alticus, Antennablennius, Istiblennius, Omobranchus and Parablennius showing differences related to general shape, that is, elliptic/oval to triangular; shape of antirostrum and its degree of development; the degrees of convexity of ventral and dorsal margins, and shape of ostium. The common/general otolith characters shared in the all studied combtooth blennies, is the heterosulcoid condition, which is a shared character with Perciformes and Gobiiformes. The type of sulcus is ostial, and it can be considered as a plesiomorph character shared with a basal group of actinopterygian fishes. The obtained results could be useful in taxonomical, paleontological, ecological and food and feeding habits studies. [ABSTRACT FROM AUTHOR]

Most studies on island biogeography have focused on the terrestrial taxa; however, there are few studies on the drivers of diversity and community structure of intertidal organisms on islands. We evaluated the effect of landscape and marine environmental factors on the species richness (SR), functional diversity (FD), and community structure (SES.MFD) of intertidal invertebrates among the overall, inhabited, and uninhabited islands. Using the data on the intertidal organisms from 78 islands in South Korea, we implemented variable selection and piecewise structural equation modeling to determine the causal relationships between the SR, FD, and SES.MFD with four landscapes (i.e., island area, coastline length, distance from the mainland, and structural connectivity) and three marine environment factors (i.e., mean annual sea surface temperature variation, wind speed, and evapotranspiration). The coastline length had a positive effect on the SR and SES.MFD in the overall islands including inhabited and uninhabited islands. The SR and FD were negatively affected by the variation in sea surface temperature. The relative importance of the landscape and marine environmental factors differed between the inhabited and uninhabited islands. That is, the inhabited islands were mainly affected by the coastline length, whereas uninhabited islands were regulated by marine environmental factors. Our results demonstrated that the biotic factors of the island intertidal ecosystems are controlled by the interactions between the biotic and various environmental factors. Moreover, the results emphasize that the water stress on the intertidal organisms due to climate change may lead to a loss of biodiversity and functional clustering. [ABSTRACT FROM AUTHOR]

In order to study the community structure characteristics of macrobenthos in the intertidal zone of Jiuzhen Bay in Fujian Province, a survey of the environmental physicochemical index of surface sediments and macrobenthos at 3 sampling points on the west coast of Jiuzhen Bay was carried out in spring (May) and autumn (September). A total of 86 species of macrobenthos belonging to 6 phyla were identified in the intertidal zone of Jiuzhen Bay in spring and autumn. The average abundance of macrobenthos in spring and autumn was 938. 13 ind • m-2 and 798. 93 ind • m-2, respectively. The average biomass was 288. 87 g • m-2 and 291. 03 g • m-2, respectively. The Shannon-Weaver index (H'), Pielou evenness index (J')and Margalef species richness index (D) of species diversity in autumn were all higher than those in spring. The pollution index (MPI) of macrobenthos in spring and autumn was 0・ 35 and --0. 36, respectively, indicating that the intertidal benthic ecological environment was moderately polluted. The results provided scientific data for the subsequent study of the ecology of macrobenthic animals in the intertidal zone of Jiuzhen Bay and the evaluation of the impact of human factors on marine ecosystems. [ABSTRACT FROM AUTHOR]

Benthic foraminifera are good indicators for monitoring marine environmental pollution and recovery of marine ecosystem. In this study, high-throughput sequencing based on small subunit rDNA and rRNA amplifications was used to assess total and active benthic foraminifera diversity and community composition in intertidal sediments near China Resources Wenzhou Power Plant. The results showed that the closer to the power plant, the lower the diversity and richness of both total and active foraminifera are. The total assemblages had higher values of species diversity and richness than active communities. a total of 33 and 25 foraminifera genera were identified using DNA-based and RNA-based HTS, respectively. The dominant genera included Vellaria, Stainforthia and Miliammina in total foraminiferal communities, and became Ammonia, Miliammina and Notorotalia in active foraminiferal communities at the station slightly away from the power plant; while only one dominant genus, Haplomyxa, was detected close to the power plant. [ABSTRACT FROM AUTHOR]

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Abstract Background Animal social systems can be described through four main components: social structure, social organization, mating system, and care system. Social structure describes the relationships between individuals in a population, while social organization describes the group composition, size, and spatiotemporal variation of a population. We use the frameworks of social structure and social organization to study the social system of Microlophus atacamensis, a lizard found in the rocky intertidal zone along the Chilean coast. The area M. atacamensis inhabits poses specific challenges stemming from their use of two distinct habitat types in the intertidal zone: they forage in the cool areas near the water’s edge and use large rocks in more inland areas for basking and refuge. Methods Our assessment of their social system focused on two separate populations: one to characterize social structure by means of focal observations and social network analysis, and a second to assess social organization via home range and core area analyses. Further, we examined the social system in two habitat types that comprise the intertidal zone: cobble fields and interspersed large rocks. Results Social network analysis revealed an interconnected network with a few highly central individuals. Body size influenced the outcomes of aggressive interactions, with interactions being more common in cobble fields where males had more associates and more repeated interactions than females. Spatial analyses revealed that the social organization of M. atacamensis is characterized by (1) high home range overlap, specifically in the cobble fields and (2) relatively exclusive core areas dispersed across both habitat types. Conclusion A social system is composed of both cooperative and competitive behaviors. While our study focused on competitive interactions, the extent and influence of cooperative behaviors is still unclear and merits future research. We suggest that M. atacamensis has a variable social system in which territoriality on large rocks affects access to stationary resources in that habitat (e.g., basking sites and refuges), while competition in the cobble fields could lay the foundation for a system of dominance relationships controlling access to variable food resources in cobble field areas of the intertidal zone.