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Copyright of Journal of Beijing University of Civil Engineering & Architecture is the property of Journal of Beijing University of Civil Engineering & Architecture Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

SUMMARY: Adaptation to new environments is a key evolutionary process which presumably involves complex genomic changes. Mangroves, a collection of approximately 80 woody plants that have independently invaded intertidal zones >20 times, are ideal for studying this process. We assembled near‐chromosome‐scale genomes of three Xylocarpus species as well as an outgroup species using single‐molecule real‐time sequencing. Phylogenomic analysis reveals two separate lineages, one with the mangrove Xylocarpus granatum and the other comprising a mangrove Xylocarpus moluccensis and a terrestrial Xylocarpus rumphii. In conjunction with previous studies, we identified several genomic features associated with mangroves: (i) signals of positive selection in genes related to salt tolerance and root development; (ii) genome‐wide elevated ratios of non‐synonymous to synonymous substitution relative to terrestrial relatives; and (iii) active elimination of long terminal repeats. These features are found in the terrestrial X. rumphii in addition to the two mangroves. These genomic features, not being strictly mangrove‐specific, are hence considered pre‐adaptive. We infer that the coastal but non‐intertidal habitat of X. rumphii may have predisposed the common ancestor to invasion of true mangrove habitats. Other features including the preferential retention of duplicated genes and intolerance to pseudogenization are not found in X. rumphii and are likely true adaptive features in mangroves. In conclusion, by studying adaptive shift and partial shifts among closely related species, we set up a framework to study genomic features that are acquired at different stages of the pre‐adaptation and adaptation to new environments. Significance Statement: We sequenced and assembled high‐quality genomes for three Xylocarpus species and one Swietenia species using single‐molecule real‐time sequencing. By illustrating genomic features acquired in different stages of the complex process of adapting to the extreme intertidal environments, we provide evidences for pre‐adaptation and adaptation in different stages of transition to a new environment [ABSTRACT FROM AUTHOR]

Copyright of Rock & Mineral Analysis is the property of Editorial Board of Rock & Mineral Analysis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A novel bacterium, designated YYF0007T, was isolated from an agar-degrading co-culture. The strain was found harboring four CRISPR-Cas systems of two classes in the chromosome and subsequently subjected to a study on polyphasic taxonomy. Pairwise analyses of the 16S rRNA gene sequences indicated that strain YYF0007T had highest 16S rRNA gene sequence similarity (92.2%) to Jiulongibacter sediminis JN-14-9T. The phylogenomic trees based on the 16S rRNA gene and 269 single-copy orthologous gene clusters (OCs) indicated that strain YYF0007T should be recognized as a novel genus of the family Spirosomaceae. The cells were Gramstain-negative, nonmotile, strictly aerobic, and straight long rods with no flagellum. Optimum growth occurred at 28°C and pH 7.0 with the presence of NaCl concentration 1.0–3.0% (w/v). The strain showed oxidase and catalase activities. The major fatty acids were C16:1ω5c, iso-C15:0 and summed feature 3 (C16:1ω7c and/or C16:1ω6c). The predominant isoprenoid quinone was MK-7. The complete genome size was 4.64 Mb with a DNA G + C content of 44.4%. Further typing of CRISPR-Cas systems in the family Spirosomaceae and the phylum Bacteroidota indicated that it was remarkable for strain YYF0007T featured by such a set of CRISPR-Cas systems. This trait highlights the applications of strain YYF-0007T in studies on the evolutionary dynamics and bacterial autoimmunity of CRISPR-Cas system as a potential model. The name Marinilongibacter aquaticus gen. nov., sp. nov. is proposed, and the type strain is YYF0007T (= MCCC 1K06017T = GDMCC 1.2428T = JCM 34683T). [ABSTRACT FROM AUTHOR]

Satellite-based synthetic aperture radar (SAR) can provide low-cost, frequent environment monitoring for dynamic intertidal zones. The critical problem is to realize pixel-level classification of SAR images of the intertidal zones with excellent and robust performance. Recently, deep learning, in particular deep convolutional neural networks, has provided us with promising solutions to this problem. Based on a sophisticated deep learning-based pixel-level classification model $\text{U}^{2}$ -Net, we propose an MB- $\text{U}^{2}$ -ACNet model suitable for intertidal zone land cover classification using dual-polarimetric SAR data integrated with environmental information, such as wind speed and tide level information. The MB- $\text{U}^{2}$ -ACNet model has a multibranch nested U-shaped encoding–decoding structure. We extract and fuse features from multiple data sources, including satellite remote sensing and environmental information, by establishing the multibranch structure. Furthermore, we propose an asymmetric convolution residual U-block for each encoding–decoding stage to improve the model’s feature extraction ability. Moreover, the model with attention mechanisms better distinguishes the importance of features from the channel’s perspectives and spatial dimensions. We construct a dataset with 106 Sentinel-1 SAR images from 2016 to 2020 for environmental monitoring in the intertidal zone of Shanghai Nanhui. On the dataset, the proposed model reaches the overall classification accuracy of 96.40% and the mean intersection over union score of 0.8307. The experiments show the advantages of the proposed model compared with the benchmarking models due to better feature extraction and multisource information fusion. In addition, the contributions of every added substructure are analyzed systematically. [ABSTRACT FROM AUTHOR]

Ammonia-oxidizing archaea (AOA) and bacteria (AOB) are the most important ammonia oxidation functional community, while the coastal environment just provides a different oxygen environment for the ammonia oxidation process. However, few surveys concentrated on the influence of oxygen concentration on the niche specialization of AOA and AOB in the ocean intertidal zones. Here, high-throughput sequencing by Illumina MiSeq and qPCR were applied to detect the change of abundance, diversity as well as community structure of both AOA and AOB with 0–60 cm sediments depth in the intertidal zone in Qingdao, China. Results showed that the AOA/AOB amoA gene copy numbers and AOA/AOB OTU numbers rate increased as sediment depth went more profound, which indicated that AOA was more adaptive to oxygen-limited niches compared to AOB. Oxygen indeed led to the niche specialization of AOA and AOB in intertidal sediments. The dominant AOA and AOB were the clusters of Nitrosopumilus and Nitrosospira, respectively, which indicated ecological success in the intertidal zone. A significant and positive correlation (p < 0.01) between AOB abundance/AOB OTU numbers and Oxidation-reduction potential (ORP) was observed. In addition, both total nitrogen (TN) (p < 0.01) and pH (p < 0.05) were significantly negatively correlated to AOB abundance. TN was also significantly negatively correlated to AOB OTU numbers (p < 0.05). Hence, oxygen led to niche specialization of AOA and AOB, especially under anoxic conditions, AOA played a dominant role in the process of ammonia oxidation. The Nitrosopumilus and Nitrosospira clusters were the dominant AOA and AOB, respectively, representing an ecological success in the intertidal zone.

The present study aims to update the red seaweed species in the intertidal zone of the Atlantic coast of Sidi Bouzid, a seaside resort near El Jadida City (Morocco) from 2016 to 2018. A particular interest was given to the new species recorded for the first time in the Moroccan coasts. The results obtained have shown an important red algal diversity in comparison to previous studies with 32 species of seaweeds that were found for the first time in this coastal area. A total of 156 species was recorded andrepresented by 35 families of red algae, where the largest number of these species belonged to Ceramiales order with 73 species, as well as 20 species of the order Gigartinales and 10 species for the Gelidiales and Corallinales orders. Among them, two epiphytes, Aglaothamnion tripinnatum and Gaillona gallica, are cited for the first time for the Moroccan coastline.

Plankton is an organism that plays an important role as a water food reserve, which is influenced by environmental conditions. This study aims to determine the community structure, abundance and biodiversity of phytoplankton and zooplankton in the intertidal zone of south coast of Yogyakarta during the rainy season. The research was conducted at Pantai Drini, Kukup, and Sundak of Gunungkidul District during December 2016 - February 2017. Sampling was conducted on three observation stations in the intertidal zone of Drini Beach, Kukup, and Sundak twice a month. The water samples were taken with plankton nets number 25, then were fluidized in 4% formalin and stored at low temperatures. The results showed diversity index of plankton in Kukup Beach in January at 1.86 while the lowest value in February at Sundak Beach was 0.87. The highest plankton abundance in January at Sundak Beach was 900 individu L-1 while the lowest value in December at Kukup Beach was 217.8 individu L-1. Based on the diversity index of Shannon-Wiener, intertidal coast waters of Yogyakarta in wet season is categorized as moderate, and dominance index is categorized as low. Plankton merupakan organisme yang berperan penting sebagai cadangan makanan perairan dan dipengaruhi oleh kondisi lingkungan. Penelitian ini bertujuan untuk mengetahui struktur komunitas, kelimpahan dan keanekaragaman plankton pada zona inertidal pantai selatan Yogyakarta selama musim penghujan. Penelitian dilakukan di Pantai Drini, Kukup, dan Sundak Kabupaten Gunungkidul selama bulan Desember 2016 – Februari 2017. Pengambilan sampel dilakukan pada tiga stasium pengamatan di zona intertidal Pantai Drini, Kukup, dan Sundak setiap dua minggu. Sampel air diambil dengan jaring plankton nomor 25, kemudian sampel plankton difiksasi dalam formalin 4% dan disimpan pada suhu rendah. Hasil penelitian menunjukan indeks keanekaragaman jenis plankton tetinggi di Pantai Kukup pada bulan Januari sebesar 1,86 sedangkan nilai terendah pada bulan Februari di Pantai Sundak sebesar 0,87. Kelimpahan plankton tertinggi pada bulan Januari pada Pantai Sundak sebesar 900 individu L-1 sedangkan nilai terendah pada bulan Desember di Pantai Kukup yaitu 217,8 individu L-1. Berdasarkan indeks keanekaragaman Shannon-Wienner maka indeks keanekaragaman di pantai selatan Yogyakarta tergolong rendah-sedang dengan indeks dominansi tergolong rendah.

Anthropogenic pressures exerted on coastal areas, combined with climate change, and accelerated sea level rise, result in the loss of natural habitats. At the same time, the number of coastal protection and defense structures have increased considerably and may become the dominant habitat in many intertidal regions. In this study we characterize the epibiota of artificial substrates (granite blocks) from coastal defense structures used to contain the effects of rising sea levels, and the same type of artificial substrate found in contact with coastal reefs located on Serrambi beach, northeast of Brazil. We mapped, measured, and photographed 45 artificial granite blocks and their surroundings in the field. A gradient was found for the number of taxa on the blocks, from high coverage by macroalgae to extensive non-colonized areas. However, it was observed that the closer to the natural reef the greater the taxonomic richness. Our results also indicate that the factor that best explains the colonization of blocks is the coverage of their surroundings, thus, few organisms were found on blocks whose surrounding unconsolidated sediment area was very extensive. In our wind and sun exposure simulation, granite rock demonstrated a more accelerated and greater level of heating (up to 3 °C) compared to fragments of natural substrate, although the variation in the slightly lighter colored and smaller granite block resembles the variation in the reef fragment. We suggest that the use of lighter-colored granite blocks at mid-coastal levels can increase the colonization rate of these substrates. [Display omitted] • There is a low richness of taxa in granite blocks from coastal defense structures in the intertidal zone. • As the granite blocks get closer to the natural reef, their taxonomic richness increases. • The factor that best explains the colonization of blocks is the coverage of their surroundings. [ABSTRACT FROM AUTHOR]

• SSH and current are downscaled using SRResNet with a scale up to 64. • Moving shorelines with wetting and drying are well tracked. • Model performance is insensitive to the number of residual blocks in SRResNet. Downscaling is the process to obtain high-resolution data from low-resolution data. Recently statistical models using convolutional neural networks have gained popularity for fast downscaling of environmental fields, while their application to the coastal sea surface height and currents is lacking. This research aims to downscale sea surface height and depth-averaged current to a resolution of hundreds of meters in coastal regions with dynamic shorelines using convolutional neural networks. Hourly outputs over one year from a physical numerical model for a coastal region in the German Bight are used as the low-resolution input and high-resolution ground truth for the network. The results show that the network effectively reconstructs sea surface height and current in the region to a resolution of hundreds of meters with a scale factor of 16 or even 64, and accurately traces the moving sea surface and shorelines. The global mean absolute error and root mean square error for the sea surface height are found to be less than 0.03 m and 0.07 m, respectively, and for the current less than 0.03 m/s and 0.05 m/s, respectively. These values are around ten times smaller than those obtained from interpolation methods including nearest neighbor, bilinear and bicubic. The network also effectively replicates the distribution of high-resolution data. The errors in the reconstructed time average, 1st percentile and 99th percentile are significantly smaller than those from interpolation methods, especially for the current. These results highlight the ability of the network to downscale sea surface height and currents in regions with complex shorelines, and have implications for downscaling other coastal fields and shoreline tracking. [ABSTRACT FROM AUTHOR]

Limpets are a key taxon regulating the benthic community structure and serving as prey for various predators in rocky shores, however, their role in food web dynamics is still unclear. To determine environmental factors influencing the limpet diet, carbon and nitrogen stable isotopes in limpets and food sources were analyzed on three different coastal habitats. Sediment organic matter contributed the most (86 %) to the limpet diet in bedrocks around tidal flats with abundant sediment supply from the terrestrial matter inflow and the sediment resuspension. Microphytobenthos and macroalgae were the main food sources (57 % and 20 %, respectively) for the limpets around beaches, where benthic flora was abundant. Limpets in bedrocks, erosional habitat, primarily consumed relatively abundant phytoplankton (33 %) and microphytobenthos (28 %). Contrary to previous studies, habitat type, rather than latitude or seawater characteristics, was the most important factor determining the limpet diet. This result also suggests that limpets are non-selective scraper that consume abundant food sources. [Display omitted] • Habitat type was the most important factor determining the limpet diet. • Sediment organic matter was the main food source for limpets around tidal flats. • Benthic flora contributed the most to the limpet diet in bedrocks near beaches. • Limpets in bedrocks primarily consumed microalgae, which are relatively abundant. • Latitude or sea characteristics were not major factors determine the limpet diet. [ABSTRACT FROM AUTHOR]

Sundarban, a Ramsar site of India, has been encountering an ecological threat due to the presence of microplastic (MP) wastes generated from different anthropogenic sources. Clibanarius longitarsus , an intertidal hermit crab of Sundarban Biosphere Reserve, resides within the abandoned shell of a gastropod mollusc, Telescopium telescopium. We characterized and estimated the MP in the gills and gut of hermit crab, as well as in the water present in its occupied gastropod shell. The average microplastic abundance in sea water, sand and sediment were 0.175 ± 0.145 MP L−1, 42 ± 15.03 MP kg−1 and 67.63 ± 24.13 MP kg−1 respectively. The average microplastic load in hermit crab was 1.94 ± 0.59 MP crab−1, with 33.89 % and 66.11 % in gills and gut respectively. Gastropod shell water exhibited accumulation of 1.69 ± 1.43 MP L−1. Transparent and fibrous microplastics were documented as the dominant polymers of water, sand and sediment. Shell water exhibited the prevalence of green microplastics followed by transparent ones. Microscopic examination revealed microplastics with 100–300 μm size categories were dominant across all abiotic compartments. ATR-FTIR and Raman spectroscopy confirmed polyethylene and polypropylene as the prevalent polymers among the five identified polymers of biotic and abiotic components. The target group index indicated green and black as the preferable microplastics of crab. The ecological risk analysis indicated a considerable level of environmental pollution risk in Sundarban and its inhabiting organisms. This important information base may facilitate in developing a strategy of mitigation to limit the MP induced ecological risk at Sundarban Biosphere Reserve. [Display omitted] • Microplastic contamination in Sundarbans leads to its accumulation in hermit crab. • Polyethylene and polypropylene are the dominant polymers. • Target Group Index reveals that crabs prefer fragmented and green microplastics. • Risk assessment classifies crab's shell water as "dangerous to extremely dangerous". • Hermit crabs are in "high" to "dangerous" risk category. [ABSTRACT FROM AUTHOR]

Kim, T., 2024. Drone observational study on coastal topographic changes in a macro-tidal environment. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 330-334. Charlotte (North Carolina), ISSN 0749-0208. This study presents the results of drone observations on the geomorphological changes of the Dasa beach in a macro-tidal environment with a tidal range exceeding 6 meters during spring tides, introducing the historical erosion incidents of the beach and dunes as well as the current dune preservation and erosion prevention measures. Over a period of one year, six drone surveys were conducted, revealing significant overall erosion and distinct patterns of erosion and deposition, particularly around the groin structures. The findings suggest that future precise and quantitative drone observations could enable in-depth studies of sediment transport in macro-tidal environments. [ABSTRACT FROM AUTHOR]

The shallow waters of the world's coasts comprise a variety of ecosystems such as tidal wetlands, salt marshes, sand flats, rocky coasts, and coral reef flats, and encompass complexes of pelagic and benthic, vegetated and unvegetated habitats. These disparate ecosystems are bound together by one common feature; that the pattern of life for marine organisms, the outcomes of process and the functioning of the ecosystems are irrevocably influenced by the tide. Focusing on the tide highlights a unique component, the intertidal zone – an area that alternates between exposure to the atmosphere and inundation by marine waters. While the tide has diverse influences on the pattern of life and on the processes that regulate ecological function in tidally dominated ecosystems , much of this can be captured in one idea, that the multi-scale predictability of tides provides vital information for the organisms utilising these systems. We explore this idea by considering the dynamics of the nekton assemblages of tidally dominated ecosystems , the roles that nekton play in the functioning of those systems, and how these dynamics are fundamentally influenced by the differential responses of nekton and their prey to the predictability of tides. Further, we discuss the nature of the information tides provide to biota, the trade-offs inherent in utilising tidally available resources, and strategies employed by biota to take advantage of the tidal information and the need for strategic trade-offs. • Coastal waters host diverse ecosystems, all linked by tides affecting marine life. • Tidal predictability influences nekton behaviour, distribution, and interactions. • Understanding tidal influences offers insights into the ecological trade-offs. • Nekton has evolved adaptive strategies to thrive in tidally dominated environments. [ABSTRACT FROM AUTHOR]

Species interactions have long been recognized as essential in the organization of communities, and the density of predators is critical in the interaction between predator and prey. Our study explores how predator density affects predation efficiency in a typical intertidal predator (dogwhelk Reishia clavigera) - prey (mussel Mytilus galloprovincialis) system. Three treatments with different predator densities were established: low-density treatment (LD, one dogwhelk/dm2), medium-density treatment (MD, four dogwhelks/dm2), and high-density treatment (HD, eight dogwhelks/dm2). The number frequency of dogwhelks on the mussel, prey searching and handling time, feeding success rate, and shell thickness of mussels were calculated. The results showed that the presence of a higher density of predators facilitated more successful predation. The higher the density of dogwhelk, the less time dogwhelks spend on predation. The predation methods of dogwhelks, either drilling holes or prying open, did not rely on predators' density, but the dogwhelks preferred to drill holes at the thin edge of the mussel shells. This study highlights the impacts of predator density on predation efficiency in the intertidal community. • Dogwhelks may scramble competition rather than cooperation. • The success of predation is greatly influenced by the density of predators. • The dogwhelks prefer to drill holes at the thin edge of the mussel shells. [ABSTRACT FROM AUTHOR]

Copyright of Bio-grafía. Escritos Sobre la Biología y su Enseñanza is the property of Universidad Pedaggica Nacional and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Probing the coverage and biomass of seaweed is necessary for achieving the sustainable utilization of nearshore seaweed resources. Remote sensing can realize dynamic monitoring on a large scale and the spectral characteristics of objects are the basis of remote sensing applications. In this paper, we measured the spectral data of six dominant seaweed species in different dry and wet conditions from the intertidal zone of Gouqi Island: Ulva pertusa, Sargassum thunbergii, Chondrus ocellatus, Chondria crassiaulis Harv., Grateloupia filicina C. Ag., and Sargassum fusifarme. The different seaweed spectra were identified and analyzed using a combination of one-way analysis of variance (ANOVA), support vector machines (SVM), and a fusion model comprising extreme gradient boosting (XGBoost) and SVM. In total, 14 common spectral variables were used as input variables, and the input variables were filtered by one-way ANOVA. The samples were divided into a training set (266 samples) and a test set (116 samples) at a ratio of 3:1 for input into the SVM and fusion model. The results showed that when the input variables were the normalized difference vegetation index (NDVI), ratio vegetation index (RVI), Vre, Abe, Rg, Lre, Lg, and Lr and the model parameters were g = 1.30 and c = 2.85, the maximum discrimination rate of the six different wet and dry states of seaweed was 74.99%, and the highest accuracy was 93.94% when distinguishing between the different seaweed phyla (g = 6.85 and c = 2.55). The classification of the fusion model also shows similar results: The overall accuracy is 73.98%, and the mean score of the different seaweed phyla is 97.211%. In this study, the spectral data of intertidal seaweed with different dry and wet states were classified to provide technical support for the monitoring of coastal zones via remote sensing and seaweed resource statistics. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Arqueología Histórica Argentina y Latinoamericana is the property of Revista de Arqueologia Historica Argentina y Latinoamericana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Algal reefs, concreted by crustose coralline algae (CCA), are the main biotic reefs in temperate waters but rare in the subtropics and tropics. The world's largest known intertidal algal reef in the subtropics is the Taoyuan Algal Reef (TAR) located in the northwestern coast of Taiwan. The biodiversity and ecology of the TAR are scarcely explored, and now the reef is imperiled by industrialization. Here, we document cryptic species of CCA in Taiwan, particularly the TAR, by sequencing the psbA genes of over 1800 specimens collected across Taiwan. We also examine the ecological background of the TAR by surveying its benthic composition and measuring its environmental parameters. Our data reveal that the TAR harbours a high diversity of cryptic CCA species (27 molecular operational taxonomic units, or mOTUs), many of which are potentially new to science (18 mOTUs) and/or endemic to the TAR (9 mOTUs). Comparing the CCA species inventory of the TAR with the rest of Taiwan shows that the TAR represents a unique hotspot of CCA taxa in the waters of Taiwan. Our analyses show that variation in the CCA assemblages in the TAR is associated with geographic distance, sedimentation, and substrate type (for example, reef vs. hermit crab shell), suggesting that dispersal limitation and contemporary environmental selection shape the CCA assemblages in the TAR. The data from this study can inform the monitoring of human impacts on the health of the TAR and contribute to our understanding of the ecological processes underlying algal reef development. [ABSTRACT FROM AUTHOR]

The purpose of this study was to further clarify marine tardigrade ecology; in particular, the monthly density fluctuations of Echiniscoides sigismundi and Styraconyx haploceros inhabiting the barnacle Fistulobalanus albicostatus in the intertidal zone. Both species were observed in all months, and the monthly body length distributions did not show a clear pattern, indicating these species breed throughout the year. However, the density of both species was higher in fall/winter than in spring/summer. The two species showed different prevalence and density distributions in the upper and lower parts of a barnacle bedrock in the intertidal zone. S. haploceros was found only in the lower part, where it dominated over E. sigismundi in most months. E. sigismundi was found in both parts, but its occurrence rate and density were higher in the lower part of the intertidal zone. The density of both species was significantly higher on the external surface of the barnacles than internally. No significant differences in tardigrade density were detected among different sizes of barnacles, living or dead, except for a significant difference in the density of E. sigismundi between dead and large live barnacles. Our findings suggest that E. sigismundi and S. haploceros are well adapted to inhabiting intertidal barnacles, and the fall/winter season is more favorable than spring/summer for marine tardigrades in temperate regions. E. sigismundi appears to tolerate the upper part of the barnacle bedrock in the intertidal zone, which may be an extremely harsh environment, better than S. haploceros. [ABSTRACT FROM AUTHOR]

Long-term variations in the structure of the Phyllospadix iwatensis community in the intertidal zone of Krabovaya Bay (Shikotan Island, Kuril Islands) under the influence of natural and anthropogenic factors were described based on the materials of the research expeditions of 1987, 1997, and 2013 with additions of literature data for 1949, 1955, and 1963. Throughout the entire period of study, the following associated macrobenthos species were recorded always in the Ph. iwatensis community: the sponge Halichondria panicea, the sipunculid Phascolosoma agassizii, the isopod Idotea ochotensis, the hermit crab Pagurus middendorffii, and the gastropods Buccinum percrassum, Nucella heyseana, and Littorina sitkana. It was shown that the organic pollution of the bay induced an increase in the species richness and population density of associated species with a simultaneous reduction in the share of dominant species biomass. After an earthquake and the tectonic subsidence of the island, the species richness of the community was found to be reduced, while the biomass of the dominant species increased. The total biomass of the community increased throughout the study period. The degree of change in the ecological state of the Phyllospadix community in the intertidal zone of Krabovaya Bay was estimated by comparison of cumulative abundance/biomass curves. [ABSTRACT FROM AUTHOR]

Physical factors affecting the survival of Tachypleus tridentatus eggs were investigated by translocating their eggs between the high intertidal zone and the low intertidal zone of a known spawning site. The mean egg survival rates per day were highest in the mid intertidal zone (45.1%±25.4%) and the lowest in the low intertidal zone (13.3%±27.6%). Differences in the elevation, air exposure time, and water content of the spawning ground were significant factors determining the egg survival rates. Excessive or insufficient air exposure time resulted in inadequate water content at higher and lower intertidal zones and could reduce egg survival. On the other hand, moderate saturation and dehydration were repeated with each tidal movement in the mid intertidal zone. This dynamic is considered as one of the crucial factors for the survival of eggs and is considered optimal for spawning. Therefore, the protection of the mid intertidal zone is imperative for maximizing the egg survival rate in Tsuyazaki Cove where almost all suitable nesting sites have disappeared due to coastal development. By protecting these optimal sites for spawning and recovering other optimal sites on suitable beaches, a positive contribution can be made to future management and conservation. The study also suggests that translocating eggs from marginal to optimal spawning sites might be a recovery strategy for this globally endangered species. [ABSTRACT FROM AUTHOR]

In order to compare the macrozoobenthic community and sedimentary environment with and without the presence of horseshoe crabs, the benthic macrofauna, sediment grain size, chromium (Cr), cobalt (Co), nickel (Ni), polycyclic aromatic hydrocarbon (PAHs), organic carbon and nitrogen were seasonally investigated at site A (with horseshoe crab presence), sites B and C (without horseshoe crab presence) in the Crocodile Island intertidal zone in Xiamen from June 2018 to July 2019. The results showed that most of the community parameters of benthic macrofauna, population parameters of common benthic macrofauna and environmental parameters were significantly different at the sites with horseshoe crab versus non-horseshoe crab sites. A two-way ANOVA test showed that the densities of Ceratonereis erythraeensis and Sigambra hanaokai had significant site variation. Cluster and non-metric multi-dimensional scaling (NMDS) analysis showed the community composition of benthic macrofauna was significantly different among the three sampling sites over four seasons. The mean sand content at site A (64.32%) was higher than those at site B (36.01%) and site C (18.86%). Conversely, the mean contents of silt, clay, Cr, Co, Ni, organic carbon, organic nitrogen, phenanthrene, and pyrene at site A were lower than those at site B and site C. These observations are consistent with the expected preferences of horseshoe crabs to live in areas with 60% sand content, which is associated with abundant and edible clamworms in the Crocodile Island intertidal zone, Xiamen. [ABSTRACT FROM AUTHOR]

The spatial and temporal decapod crustacean (DC) catch composition (CC) and its sex ratio (SR) taken from Tiworo strait were studied. Monthly samples from different habitat characteristics of intertidal zone (station A), river mouth (station B), sea grass (station C), and water depth of > 30 m (station D) using collapsible crab pots and gillnets were recorded, identified its species, sexed, counted its number, and analyzed its spatial and temporal CC and SR. The Chi-square test (a = 0.05) was used to test significant differences of expected 1: 1 SR. It was 12 DC species had been identified which BSCs were found at the entire stations and all years round. It had high CC at each station ranging 21.561-79.176% which was found the highest at station A, while CC in each month ranging 43.023-71.898% which was mostly found in March and April. Its CC reached 60.589% of total catch. The CC of other dominant species of C. anisodon, C. hellerii, and T. crenata had 5.721-50.186%, 0.458-1.550%, and 1.931-10.781%, respectively, while the rest species had CC of <3%. Spatial and temporal SR of females BSCs always preponderated over males, while C. anisodon, T. crenata, and T. danae were in contrary. Similar results were also showed for overall sex ratio of each species. The other species were mostly no patterns of SR. Chi-square test showed that those SRs were mainly significant different (P < 0.05). Data of CC implies that this waters constitutes main habitat for BSCs which prefer intertidal zone grown by mangroves (station A) particularly in March and April. Other species such as C. anisodon, T. crenata, and T. danae as bycatch which relatively low their CC may show that their population had been experiencing heavy pressure. Therefore, an action reducing bycatch should be implemented through for example providing fishing gears selective. The present BSC SR should be put in management policy in order to maintaining female adults are available all years round to produce eggs, hatch and grow to be juveniles. Therefore, BSC population stocks in this waters are continuously sustained. [ABSTRACT FROM AUTHOR]

Diversity and distribution study of Stomatopoda has been carried out in selected locations of Gulf of Kachchh from 2014 to 2020. Four species belonging to four genera in two families were recorded from Gulf of Kachchh, Gujarat. Carinosquilla multicarinata (White, 1848) was recorded for the first time from the west coast of India. Cloridina ichneumon (Fabricius, 1798) was recorded for the first time from Gujarat coast. Gonodactylellus demanii (Henderson, 1893) was reported after 50 years from Gulf of Kachchh, Gujarat, and Gonodactylus smithii Pocock, 1893 is a commonly occurring species in the intertidal zone of the Gulf of Kachchh. Species are described and illustrated with key characters and distributional status in Gulf of Kachchh. An annotated checklist of nine species of Stomatopoda occurring in Gujarat is presented. [ABSTRACT FROM AUTHOR]

Understanding large-scale spatial and temporal patterns of marine populations is a central goal in ecology, which has received renewed attention under climate change. However, few studies explore the large-scale dynamics of populations using standardized protocols and during the same time frames. We studied the phenology and intensity of reproduction and recruitment for the intertidal stalked barnacle Pollicipes pollicipes over an European scale and described their potential linkages with environmental variables. This species supports profitable fisheries in the Iberian Peninsula (Spain and Portugal). In Brittany (France), we had observed a significant lower reproductive effort (long non-breeding season, short breeding period in summer) and low values of recruitment intensity. This pattern may be related to the fact that Brittany corresponds to the northern limit of the distribution of this species in continental Europe. On the Iberian Peninsula, the most different region was Galicia (Spain), with Asturias (Spain) and SW Portugal being more similar. In Galicia, we have observed a contradictory pattern characterized by the absence of a non-breeding period and by a shorter recruitment season than observed in other Iberian regions. Our results suggest that air temperature, SST and chlorophyll-a might be related to the variability in reproduction and recruitment patterns of P. pollicipes. Moreover, spring and early summer upwelling in SW Portugal and Galicia might be inhibiting recruitment in this period. At the northern limit, the expected increase in performance under climate change might facilitate the recovery of populations after exploitation, increasing the resilience of the resource to fishing pressure. [ABSTRACT FROM AUTHOR]

Abstract Carapace width-carapace length (CW/CLRs), carapace width-weight (CW/WRs), and carapace length-weight (CL/WR) relationships are presented for the portunid species Callinectes bocourti A. Milne Edwards, 1879, Callinectes danae Smith, 1869, and Callinectes ornatus Ordway, 1863 from the northern coast of Brazil. A total of 85 crabs were collected between May and October 2015 in intertidal zones of the Caeté, Pirabas and Salinas estuaries. All species had strong relationships between measurements with a coefficient of determination (r 2) ranging between 0.97 and 0.99. The variable most strongly related to CW was CL with 99 % of the variability provided by C. ornatus. These relationships are a useful tool for field ecologists to estimate length and/or mass of portunid species, and it is not necessary to euthanize the organism to collect body measurements. Additionally, this study describes the first reference of CW/CLRs and CL/WRs for these portunid species in the region. The Callinectes species in Amazon estuaries are still poorly studied, and there is a need for monitoring their stocks due to its importance for artisanal fishery. The present data are important for supplying biological information required for an adequate management of this fishery.

The effect of grazers on the diversity, distribution, and composition of their principal food source has rarely been described for the high intertidal zone of rocky shores, a model system for studying the potential effects of climate change. Along rocky, wave-swept shores in central California, the microphytobenthos (MPB) supports diverse assemblages of limpets and littorine snails, which, at current benign temperatures, could potentially partition food resources in a complementary fashion, thereby enhancing secondary productivity. Two limpet species in particular, Lottia scabra and L. austrodigitalis, may partition components of the MPB, and are likely to affect the composition of the MPB on which they graze. In this study, we describe the composition, nutritional value (C:N ratio), and fluorescence (an index of chlorophyll density) of ungrazed, L. scabragrazed and L. austrodigitalis-grazed MPB, each as a function of temperature. Fluorescence de-creased with increased average daily maximum temperature for ungrazed MPB, but temperature had no discernible effects on either fluorescence or the composition of the MPB of grazed assemblages. L. austrodigitalis and L. scabra did not partition the MPB, and did not exhibit complementarity. Both species exhibited an ordered grazing scheme, in which limpets grazed down certain components of the MPB before others, and grazing increased the C:N ratio of the MPB, decreasing its nutritional value. Taken together, these results suggest that L. austrodigitalis and L. scabra may experience increased competition as warming temperatures reduce the available MPB.

The conservation of an endangered horseshoe crab, Tachypleus tridentatus, has been increasingly emphasized worldwide. Although monitoring of T. tridentatus reproduction is effective for its conservation, the conventional monitoring system for spawning has several drawbacks. Thus, our study aimed to examine the environmental DNA (i.e., eDNA) approach to assess T. tridentatus spawning events. Six survey sites were set at the sandy beaches of the Sone tidal flat, Japan. Visual observations of the spawning events, i.e., the presence/absence of adult pairs of T. tridentatus or that of foams, occurring because of their spawning behavior, and water sampling for eDNA assay were conducted 10 times at each site between 2019 and 2020. The spawning events were observed at a total 16 sites during the surveys, and the estimated numbers of T. tridentatus adult pairs were 1--5 per site. T. tridentatus DNA was detected in 15 of the 16 samples at the sites where the spawning events were observed and in 13 of 44 samples where the spawning events were not observed. The estimated number of pairs and the eDNA concentration showed a significantly positive correlation. Moreover, the presence/absence of the spawning events was distinguished with excellent accuracy based on the eDNA concentration. Therefore, our results showed that the spawning events of the species and the eDNA concentration were closely related. In conclusion, we expect that the population of T. tridentatus in spawning grounds can be evaluated more complementarily by combining the conventional observation method with the eDNA approach. [ABSTRACT FROM AUTHOR]

Intraspecific variation in morphology is widespread among seaweed species in different habitats. We examined the morphological variation in Sargassum thunbergii involving diverse environmental factors. We quantified 16 morphological characteristics on 15 rocky intertidal shores in Korea. A cluster analysis based on morphology identified three groups. Group M1 comprised populations on the northern part of the east coast, where the thalli was short and thick, with large leaf and air-vesicle. Group M3 consisted of populations on the west coast exclusively separated from other populations, with short, slender and sparsely branched thalli. Group M2 comprised populations on the southern part of the east coast and on the south coast (including Jeju Island), with longest thalli and lateral branches. Principal coordinate analyses showed that group M1 and M3 were mostly influenced by strong wave action and large tidal amplitudes, respectively. Group M2 were under the influence of warm temperatures and high irradiance. Biota-environment matching analysis showed that the morphology is affected by combinations of different local environmental factors and also that tidal condition is important as a single variable, suggesting that morphology of S. thunbergii reflects and adapts to local environmental conditions. [ABSTRACT FROM AUTHOR]

In contrast to a great diversity in insects in terrestrial and freshwater ecosystems, few known species have adapted to inhabit marine environments. In this study, we surveyed insects associated with halophytic plants of Suaeda (Amaranthaceae) distributed in intertidal zones, in northern Kyushu, Japan. On four Japanese native species of Suaeda, we found insects belonging to five orders and 18 species. Amongst them, the genus Clanoneurum (Diptera: Ephydridae) and Coleophora deviella (Lepidoptera: Coleophoridae) were newly reported from Japan; and Orthotylus (Melanotrichus) parvulus (Hemiptera: Miridae) was newly recorded from Kyushu. The seasonal occurrence of several insects on Suaeda is reported. [ABSTRACT FROM AUTHOR]

Plumb Beach, Brooklyn, New York in USA is an important horseshoe crab breeding and nursery ground that has experienced substantial anthropogenic influence, including pollution, erosion and subsequent restoration. Since little is known about the relationship between sediment microbial communities and juvenile horseshoe crab survival, next generation sequencing was used to characterize and compare the sediment microbiome of three distinct areas of Plumb Beach:- a tidal creek with abundant juveniles, East Beach with moderate number of juveniles, and West Beach- a highly disturbed area where juvenile crabs are rarely seen. The microbiome of juvenile crab intestinal content (both dissected gut content and fecal flush content) from the tidal creek site was also examined. The results showed that in our 2017 survey, the overall dominant sediment orders at all beach sites were Vibrionales (30%), Flavobacteriales (22%) and Alteromonadales (21%). Although alpha diversity was similar among the three beach sites, Bray-Curtis distances assessed by Permanova revealed significant differences in Beta diversity, with a unique microbial assemblage found in the tidal creek. Both crab gut and fecal flush samples did not sequence well, showing low species diversity and very high variability. This study is the first to use next generation sequencing to characterize Plumb Beach sediment microbes and the first attempt to examine the gut microbiome of juvenile horseshoe crabs. This information will contribute to understanding the relationships between sediment microbial assemblages and juvenile crab populations within this important urban habitat.

In natural environments, two or more abiotic parameters often vary simultaneously, and interactions between co-varying parameters frequently result in unpredictable, non-additive biological responses. To better understand the mechanisms and consequences of interactions between multiple stressors, it is important to study their effects on not only fitness (survival and reproduction) but also performance and intermediary physiological processes. The splash-pool copepod Tigriopus californicus tolerates extremely variable abiotic conditions and exhibits a non-additive, antagonistic interaction resulting in higher survival when simultaneously exposed to high salinity and acute heat stress. Here, we investigated the response of T. californicus in activity and oxygen consumption under simultaneous manipulation of salinity and temperature to identify whether this interaction also arises in these sublethal measures of performance. Oxygen consumption and activity rates decreased with increasing assay salinity. Oxygen consumption also sharply increased in response to acute transfer to lower salinities, an effect that was absent upon transfer to higher salinities. Elevated temperature led to reduced rates of activity overall, resulting in no discernible impact of increased temperature on routine metabolic rates. This suggests that swimming activity has a non-negligible effect on the metabolic rates of copepods and must be accounted for in metabolic studies. Temperature also interacted with assay salinity to affect activity, and with acclimation salinity to affect routine metabolic rates upon acute salinity transfer, implying that the sublethal impacts of these co-varying factors are also not predictable from experiments that study them in isolation., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2024. Published by The Company of Biologists Ltd.)

Coastal areas have been intensively urbanized in Asia, causing changes to the structure and function of intertidal macrobenthic communities. In this study, the intertidal assemblages on two natural rocky shores, two rocky shores disturbed by construction works, and two shores with mixed artificial seawalls and mudflats in the Dongtou Islands were studied. We examined the influence of coastal engineering by comparing macrobenthic community structures in different transects. The statistical results revealed significant differences between macrobenthic community structures in natural and influenced transects, although all the high tidal zones shared common species. The most common species on mudflats were opportunistic polychaetes; however, historical evidence suggests that the mudflats in Dongtou used to be dominated by Mollusca. We inferred that this change in community structure occurred when the seawalls were constructed five5 years previously. The macrobenthic community does not appear to have subsequently recovered. We also observed an absence of habitat-forming macroalgae in our study area, although similar investigation results revealed that they still prevail on an uninhabited island in Dongtou. The increasing disturbance caused by construction work may explain the decline in brown algae, which are mainly distributed in the low tidal zone. [ABSTRACT FROM AUTHOR]

The only previous study on the macrobiota of South African boulder shores showed this assemblage to be more diverse than on nearby rocky platforms, but the drivers of that difference remain unresolved. We recorded water and air temperatures under intertidal boulders and on adjacent exposed rocky platforms, at both the upper- and lower-shore level, at Kommetjie, South Africa, over 2-week tidal cycles, repeating this during summer and winter. The macrobiota in each location was also sampled during diurnal low tides. The most-extreme temperatures, and greatest ranges, occurred during summer on upper-shore open rock (13.9–37.7 °C, range difference of 23.8 °C), while under upper-shore boulders the maximum temperature was lower at 28.9 °C and the range spanned only 15.5 °C. In winter, maximum temperatures and ranges were lower at all locations. Maximum temperatures did not coincide with spring tides, but occurred several days later, when low tides happened during the heat of the day. Closer analysis of daily fluctuations revealed influence of weather on temperatures attained and showed that durations of elevated temperatures were much shorter in the lower shore. The upper shore exhibited low biodiversity, supporting only 9 species, with 8 found only under boulders during diurnal low tide; the lower shore was more diverse, with 11 species on open rock and 29 under boulders. Biomass and abundance were also higher under boulders at both levels, especially on the upper shore. More-benign under-boulder conditions thus facilitate more abundant and diverse biota sheltering there than occurs on adjacent exposed rocks, particularly on the upper shore. [ABSTRACT FROM AUTHOR]

The Japanese pygmy octopus, Octopus parvus, is a small octopus that commonly occurs along the coast of southern Japan; however, the ecological information is limited. This study investigated the annual seasonal occurrence of O. parvus in the intertidal zone of Fukue Island, Nagasaki, Japan, and examined its growth, maturation, and feeding habits. We found 140 individuals in the intertidal zone from August to January, and zero from March to July. During the emergence period, they appear to move from the high to low intertidal zone, and subsequently migrate to the subtidal zone. During low tide at night in the intertidal zone, we observed that the octopuses actively captured and fed on prey, such as fish, crabs, hermit crabs, shrimp, gastropods, and bivalves. The body size of collected individuals increased significantly from summer to winter. Both males and females were found to be characterized by similar body sizes and growth, although gonadal development occurred earlier in males. However, no mating or brooding behaviors were observed during the course of the study. Our observations thus indicate that O. parvus uses intertidal zones as feeding grounds for rapid growth and maturation, and may thereafter move to the subtidal zone for spawning. [ABSTRACT FROM AUTHOR]

Green tides originate from the rapid growth of green macroalgae and their large accumulation. In the past few decades, the severity and frequency of green tides have increased and the range of their geographical distribution has widened. In recent years, Ulva meridionalis Horimoto et Shimada has been reported in many countries. This species has stable morphological characteristics, and its length can reach 3 m in indoor cultures. Its cells contain pyrenoids, and the sporangium and gametangium of each cell contain 8 spores and 16 gametes, respectively, which confer a high proliferation potential. The phylogenetic tree constructed in this study showed that the Internal Transcribed Spacer sequence identified U. meridionalis with a high identification reliability, and the genetic relationship between U. meridionalis and Ulva pertusa in the ITS sequence was close. The haplotype network analysis clarified the relationship of the U. meridionalis samples collected from four different sea areas in China and indicated that they were closely related. Five haplotypes were identified: Hap_2 and Hap_1 were the most frequent, and they were also the haplotypes shared among the three groups. The degree of subspecies formation was not reached among these U. meridionalis samples collected from the Chinese seas. Up to 20 years ago, U. meridionalis had only been recorded in Japan. After 2011, it has been found to be widely distributed in the United States, China, French New Caledonia, French Polynesia, and Australia, where it proliferates. It has spread as a new kind of green tide-forming macroalga. The present study found that U. meridionalis is widely distributed in the Chinese seas; specifically, there have been small-scale blooms in the Bohai Sea, the Yellow Sea, and the South China Sea. Further investigations should focus on establishing whether U. meridionalis will cause large-scale green tide events in the future.

Several attempts have been made to find universal zonation schemes for the benthic fauna in sandy beaches. Usually, the nature and number of zones are not fixed and depend on the beach type and temporal changes in environmental characteristics. We characterized spatial and temporal variations in the structure of macrobenthic communities on an Amazonian macrotidal sandy beach (Farol Beach, Algodoal‐Maiandeua Island, Brazil). Samples (macrobenthos and sediments) were collected during the rainy (March 2012 and 2013) and dry seasons (September 2011 and 2012) at six equidistant sites (50 m apart) from the high tide water mark to the swash zone. The physical gradients influenced the faunal distribution, with significant seasonal variations. Density and diversity increased seaward, while increasing moisture, organic matter content, and fine grains in sediments. Two faunal zonation schemes were observed. In the dry season, three faunal zones were distinguished: upper‐intertidal, mid‐intertidal, and low‐intertidal, whereas in the rainy season, only two faunal zones were distinguished: upper‐intertidal and low‐intertidal. In the rainy season, the physical gradients along the intertidal appeared to be smooth, allowing the expansion of the upper‐tidal zone. This study provides novel insights into macrobenthic distribution patterns, reinforcing that tropical macrotidal beaches have unique characteristics that strongly influence macrobenthic distribution patterns. [ABSTRACT FROM AUTHOR]

The bacterial decay of waterlogged archeological wood (WAW, hard pine spp.) taken from Daebudo shipwreck No. 2, which was buried in the intertidal zone in the mid-west coast (Yellow sea) of South Korea approximately 800 years ago, was investigated. The maximum moisture content of the outer parts (approx. 3 cm of depth) of WAW was approximately 4.2 times higher than that of undegraded reference pine wood. ATR-FTIR and solid-state 13C-NMR analysis indicated a relative increase of the lignin concentration in WAW caused by the degradation of cellulose and hemicelluloses across the board studied (31-cm-wide and 14.5-cm-thick board). Micromorphological studies also revealed that bacterial degradation was progressed to a depth of 15 cm (vertically 7.3 cm) from the surface, which is the innermost part of the board. Erosion bacteria (EB) were identified as the main degraders of WAW. Degradation by tunneling bacteria (TB) was occasionally detected. Decay resistance to bacterial attacks in WAW varied between cell types and between cell wall regions. Axial tracheids showed less resistance than ray tracheids, ray parenchyma cells, and axial intercellular canal cells, including strand tracheids, subsidiary parenchyma cells, and epithelial cells. Decay resistance was higher in ray tracheids and strand tracheids than in ray parenchyma cells and subsidiary parenchyma-/epithelial cells, respectively. Bordered- and cross-field pit membranes and the initial pit borders showed higher decay resistance than the tracheid cell walls. Overall, the S2 layer of the axial tracheids showed the weakest resistance to bacterial attacks. [ABSTRACT FROM AUTHOR]

Invasive species often exhibit disproportionately strong negative effects in their introduced range compared to their native range, and much research has been devoted to understanding the role of shared evolutionary history, or lack thereof, in driving these differences. Less studied is whether introduced species, particularly those that are important as facilitators in their native range, have persistent positive effects in their invaded range despite a lack of a shared evolutionary history with the invaded community. Here, we manipulated the density of a habitat‐forming facilitator, the high intertidal acorn barnacle Balanus glandula, factorially with herbivore density in its native range (Bluestone Point, British Columbia, Canada) and invaded range (Punta Ameghino, Chubut Province, Argentina) to determine how this facilitator differentially affects associated species at these two locations. Given that high intertidal species at Punta Ameghino (PA) are evolutionarily naïve to barnacles, we predicted that the positive effects of B. glandula at PA would be absent or weak compared to those at Bluestone Point (BP). However, we found that B. glandula had an equally positive effect on herbivore biomass at PA compared to BP, possibly because the moisture‐retaining properties of barnacle bed habitats are particularly important in seasonally dry Patagonia. Barnacle presence indirectly decreased ephemeral algal cover at BP by increasing grazer pressure, but barnacles instead facilitated ephemeral algae at PA. In contrast, B. glandula increased perennial algal cover at BP, but generally decreased perennial algal cover at PA, likely due to differences in dominant algal morphology. Though our experiment was limited to one location on each continent, our results suggest that shared evolutionary history may not be a prerequisite for strong facilitation to occur, but rather that the nature and strength of novel species interactions are determined by the traits of associated species and the environment in which they occur. [ABSTRACT FROM AUTHOR]

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Microplastic pollution has been recognised as a global threat in marine environments and a danger to prey, predators and humans. Yet, there have been few studies in the western Indian Ocean, specifically along the Kenyan coast, which makes it difficult to estimate the extent of such pollution in the region. This is the first study on microplastics (MPs) in the sediments within creeks and estuaries (Tudor, Port Reitz and Mida creeks) on the Kenyan coast. In January/February and September 2018 sediment samples were collected for MPs analysis. The concentration of MPs differed between the sampling seasons and was distinctively higher in the second sampling season across particle sizes, suggesting that there were more MPs from larger terrestrial discharges due to increased runoff. The concentrations of total MPs, and the occurrence of different sizes, shapes and colours, were established under a microscope. The overall mean concentration was highest for the large size category of MPs (500–4 999 µm) at 9.1 (SE 0.8) particles cm−2, with Tudor Creek being more polluted with MPs than Port Reitz and Mida creeks. We recommend formulation of policies on proper plastic waste management and disposal to protect nearshore ecosystems which are rich in marine biodiversity. [ABSTRACT FROM AUTHOR]

Heavy metal pollution is an increasing threat to the marine environment and is a major health concern. Both marine limpets and algae have been employed as biomonitors elsewhere in the world, but there are few or no data for these taxa along the South African coast. We investigated heavy metal concentrations in the tissues of selected limpet and algae species sampled at four sites on the southeast coast of South Africa (Silaka, Hluleka, Mthatha and Mbhashe), and determined whether there was any relationship between heavy metal concentrations in the limpets and their algae food sources as evidenced by the trophic transfer factor (TTF). Samples were collected in July 2019 and the tissues were digested following normal protocols. Heavy metals were detected using inductively coupled plasma optical emission spectrometry (ICP-OES). Significant differences in metal concentrations were observed among the algae species. The soft tissues of limpets from Silaka had the highest heavy metal concentrations, and samples from Mthatha had the lowest, with only mercury (Hg) occurring in high concentrations. Metal concentrations in soft tissues were generally 10-times higher than in shell tissues and differed between lower- and upper-shore species. Cadmium (Cd) biomagnified (TTF > 1) in all limpet species at all sites. Cd, arsenic (As), lead (Pb) and Hg measured in our study were above the maximum limits set by the South African Department of Health. This study suggests that the use of limpet and algae species as bioindicators is feasible since they are widely distributed and can accumulate a wide range of heavy metals. [ABSTRACT FROM AUTHOR]

Purpose: The intertidal and supratidal coastal zone challenges the osmoregulatory capacity of aquatic inhabitants. Four new species of Gyrodactylus ectoparasites on two intertidal fishes from Chile are described based on molecular and morphological analyses. Methods: Monogeneans were found from two fish species, the clingfish Sicyases sanguineus Müller & Troschel, 1843 and the combtooth blenny Scartichthys viridis Valenciennes, 1836. The morphology was described by drawings, and minimal measurements. The parasites were barcoded via the sequencing of the ribosomal DNA over ITS1-5.8S-ITS2. Results: The air-breathing clingfish S. sanguineus carried Gyrodactylus amphibius sp. nov., hiding in the ventral sucker formed by the modified pectoral fins of the fish. The intertidal combtooth blenny S. viridis carried three other new species: Gyrodactylus scartichthi sp. nov., Gyrodactylus viridae sp. nov., and Gyrodactylus zietarae sp. nov. Conclusion: The four new species were all phylogenetically related with the previously described G. chileani Ziętara et al. 2012 on triplefin Helcogrammoides chilensis Cancino, 1960 in the same habitat. Thus, the five Chilean Pacific Gyrodactylus species formed a statistically well-supported (100%) monophyletic clade together with three geographically distant species recorded in Europe. The Chilean Pacific parasites are not related to G. salinae and G. magadiensis, parasites described in extreme osmotic stress environments earlier. [ABSTRACT FROM AUTHOR]