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As one of the major limiting environment factors in aquaculture, ammonia nitrogen brings severe threat to the growth and survival of aquatic animals, especially mollusk in benthic zones. However, the molecular mechanism underlying the toxic response and tolerance of mollusks to ammonia nitrogen remain unclear. In this study, transcriptome, metabolome and physiological indicators were combined to investigate the metabolic mechanism of adult razor clam (Sinonvacula constricta), which was exposed to -46mg/L ammonia nitrogen for 1 day (A1) and 10 days (A10). It was observed that compared with A1, the contents of free amino acids, including taurine (Tau), alanine (Ala) and arginine (Arg), the activities of immune-related enzymes acid phosphatase (ACP) and alkaline phosphatase (AKP), and antioxidation-related enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPX) in hepatopancreas, were significantly increased in A10, while the content of malondialdehyde (MDA) was significantly decreased (P < 0.05). Furthermore, the contents of glucose and pyruvate in hepatopancreas, foot and hemolymph urea nitrogen (HUN) were significantly changed (P < 0.05). Meantime, the comparative transcriptome analysis between A1 and A10 groups revealed the effects of ammonia stress on immune defense, antioxidant system and metabolic pathway. Likewise, metabolomic analysis showed that ammonia exposure interfered with amino acid metabolism, lipid metabolism and carbohydrate metabolism, with metabolism related-genes changed according to RNA-seq analysis. By comparing the metabolites and transcripts profiles of A10 and A1, the expression of some genes involved in detoxification and ammonia excretion was significantly changed. Combined with the changes in metabolites, we speculated that the convert endogenous ammonia to alanine, alanine-glucose cycle and urea synthesis might be adaptive strategies of the razor clam after ammonia stress. Collectively, the combination of physiological, transcriptome and metabolome will greatly contribute to the progressively understand the toxicity of ammonia exposure and the defense mechanism of razor clam against ammonia toxicity, and provide new sights on the potential molecular mechanisms of ammonia adaptive strategies in benthic mollusk. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to determine the reproductive cycle and spawning frequency of the sea cucumber Holothuria tubulosa in the northeastern Aegean Sea. Methods: The study covered a period of 12 months, beginning in October 2018 and concluding in September 2019. During this period, sea cucumber samples were collected monthly. Macroscopic and histological examinations of gonadal tubules were conducted to provide credible information for fishery management and aquaculture. Result: The sex ratio of the sampled population was 1:1.3, with 95 males and 130 females. The drained body weights at 50% maturity were 70.90 g for females and 70.80 g for males. The total length at 50% maturity was estimated at 18.58 cm for females and 18.05 cm for males. Gonad maturation was initiated in March and progressed to spawning stages between July and August. From September to February, the gonads were in postspawning and recovery stages. A strong linear correlation was determined between the gonad index and the seawater temperature in the area. Conclusion: The information provided is expected to improve stock management, enforce fishery regulations, and support controlled breeding programs. These measures aim to preserve the natural populations of Holothuria tubulosa and guarantee the long‐term viability of the species in the wild. Impact statementThe Holothuria tubulosa is the most abundant commercial sea cucumber species found in the Mediterranean Sea, particularly in the Aegean Sea. This species plays an important ecological role in nutrient regeneration and surface sediment mineralization in the benthic zone; however, there is significant catch pressure on natural stocks. This study revealed the reproductive cycle of this Mediterranean Sea cucumber species, offering crucial data for sustainable fisheries and aquaculture. By understanding their breeding patterns, we can better manage wild populations and develop controlled breeding programs, ensuring the long‐term survival of the species and supporting healthy marine ecosystems. [ABSTRACT FROM AUTHOR]

This article provides an overview on human aeroecology, covering a range of subjects including the impact of air distribution systems on airborne disease transmission, the role of soundscapes in promoting restoration, the effects of face masks on speech perception, and the use of IoT sensors for controlling cooking emissions. The document also covers topics such as phytoremediation, green roofs, and the relationship between indoor air quality and human performance. [Extracted from the article]

Euxinia, a crucial geological condition, usually signifies more severe extinction events attributed to deoxygenation in Earth's history. Despite extensive exploration of various proxies in paleoredox studies, most are primarily utilized to reconstruct atmospheric pO2, the proportion of anoxic water relative to the entire basin, and broader trends in redox states. Few, however, hold the capacity to precisely delineate local euxinia within confined areas. To address this gap and gain insights into the temporal and spatial extent of benthic euxinia, we propose leveraging the synergistic analysis of total nitrogen isotopes (δ15NTN) and pyrite sulfur isotopes (δ34Spy). Our study focuses on the Triassic Chang 7 Member from the Yanchang Formation, Ordos Basin, North China. Through coupling the δ15NTN and δ34Spy systematics on 11 drill cores within the Ordos Basin, we reconstruct the temporal and spatial distribution of the benthic euxinia zone during the Chang‐7 period. Our results suggest strong spatial heterogeneity of benthic redox conditions, with the euxinia boundary shifting from the central lake to the southwestern sections. Moreover, we identify redox‐controlling factors, including organic carbon loading, water depth, and potential water circulation, and evaluate their interplay with benthic euxinia. Furthermore, the discernment of water circulation patterns may provide an innovative approach to restore the paleowind direction. These findings highlight the effectiveness of coupling δ15NTN and δ34Spy in reconstructing the local benthic redox landscape of benthic environments, and enrich our understanding of biogeochemical processes. Plain Language Summary: Understanding past oxygen levels in Earth's waters is crucial for tracing its evolution and habitability. Euxinia, marked by severe deoxygenation, is a key indicator of environmental conditions. While a series of proxies have been used, only a handful of them are applicable to local euxinia identification, especially for lake systems that may possess unique thresholds, complicating the investigation of their biogeochemical processes. The coupling of nitrogen‐sulfur isotopes is innovatively raised to distinguish local bottom euxinia from more oxic (i.e., non‐euxinic) settings. The reconstructed redox landscape of the Triassic Ordos Basin exhibits strong spatiotemporal diversity. The temporal evolution is mainly controlled by water depth, while the spatial heterogeneous euxinia distribution is probably dominated by water circulation, mainly influenced by paleowinds at the surface of lake water. These deductions align with geochemical, tectonic, and sedimentological observations, such as ancient topography of the basin and thickness distribution of tuff layers. These findings put forward a unique window for identifying local euxinia and investigating paleowind orientation. Key Points: Systematic analyses of C‐N‐S‐Fe geochemistry of the Triassic Ordos Basin were conductedThe spatiotemporal paleoredox landscape was reconstructed by the coupling of nitrogen‐sulfur isotopesThe temporal and spatial heterogeneity of euxinia was controlled by water depth and water circulation/ventilation, respectively [ABSTRACT FROM AUTHOR]

Mixing processes in lakes are important in determining sedimentation zones and in setting the so‐called "wash zone", the area of lake bottom in contact with an oscillating thermocline during wind‐driven internal seiche events. The wash zone also aligns with a sharp change in sediment roughness and hardness. Taken together, these rapid changes in temperature and sediment indicate that the wash zone is a distinctive ecotone in stratified lakes. Depth stratified randomised netting was used to develop count‐based habitat use models for three common benthic fish species as a function of depth or temperature covariates. Using data from two lakes with quite different wash zone depths, we show the wash zone to describe fish habitat for two of three benthic fish species by utilising the top 50% of estimated fish abundance as an indicator of habitat use. White sucker (Catostomus commersoni) habitat use was within the boundaries of the wash zone. Lake whitefish (Coregonus clupeaformis) habitat was adjacent and within the wash zone. Longnose sucker (C. catostomus) habitat use was in the deep areas of lakes dominated by sediment focusing and did not overlap white sucker. Lake whitefish habitat use overlapped both catostomids, but peak abundance of both lake whitefish and white sucker overlapped pointing to potential interactions between these species. Smaller lakes have less vigorous mixing processes and a narrower wash zone, so with a decline in lake size the likely area of the wash zone as habitat for benthic feeding fish would become smaller. [ABSTRACT FROM AUTHOR]

High-mountain lakes are freshwater ecosystems situated above the tree line which are known for their remote locations and limited accessibility. These ecosystems host simplified biotic communities primarily concentrated in the littoral zone and dominated by benthic macroinvertebrates that serve as bioindicators of environmental pressures. A two-year monitoring investigation was performed in July 2022 and July 2023 at Nero Lake (Cesana Torinese, Northwest Italy). Five sites along the lakeshore were selected for sampling physicochemical water parameters and macrobenthos. All collected data were analysed to compare trends across years and within specific sites. The results revealed that Nero Lake exhibited consistent macrobenthic communities across the two years studied, but significant differences were observed in its microhabitats. This suggests that substrate type and physicochemical water parameters strongly influence community composition. Chironomidae larvae and Mollusca were the dominant species, showing distinct associations with different substrates and environmental factors from one year to another. These findings contribute to our understanding of the intricate relationships between benthic macroinvertebrates and their environments, highlighting the necessity of detailed, small-scale assessments to comprehend ecosystem dynamics and develop effective conservation strategies. [ABSTRACT FROM AUTHOR]

The Eocene Kuldana Formation (KF) in the Yadgar area of Pakistan, comprises a diverse range of sedimentary facies, including variegated red beds of shales, mudstones, and sandstones, as well as interbedded limestone and marl. In this study, we conducted an integrated micropaleontological, sedimentological, mineralogical, and geochemical investigation to determine the depositional setting, biochronology, provenance, and paleoclimate of the KF. The study identified six lithofacies and six microfacies, which indicate a variety of environments ranging from floodplains and channels to the margins and shallow marine settings. The nannofossil biostratigraphy places the KF in the Early Eocene, more precisely the NP10 zone (Ypresian), and the fossil zone of benthic foraminifera classifies the study section as the Shallow Benthic Zone SBZ-8 (Middle Ilerdian 2). In terms of petrography, the KF sandstone was classified as litharenite and feldspathic litharenite, while the QtFL diagram suggests a recycled orogen. Geochemical proxies indicate an oxidizing environment, a high-to-low regular sedimentation rate, moderate-to-intense chemical weathering in the source region, and a warm-humid to dry climate during the deposition of KF. Overall, the findings suggest that the deposition of KF marks the end of Neo-Tethys due to the Early Eocene Indian–Kohistan collision and that the uplifting of the Himalayas provided the source for the deposition of KF in the foreland basin. The study provides new insights into the depositional environment, biochronology, provenance, and paleoclimate of KF, and highlights the potential for red beds as reliable indicators of oxygenation levels in proximity to mineral deposits. [ABSTRACT FROM AUTHOR]

Harmful algal blooms (HAB) are natural environmental occurrences that can disrupt ecosystem function that supports fisheries and aquaculture, as well as rendering harvested seafood, especially shellfish, unsafe for consumption by humans or wildlife species. Many dinoflagellates that cause HAB have a life cycle with a sexually produced resting stage called the resting cyst. The resting cyst enables the species to persist in an area where conditions for growth vary seasonally. These species often are found as vegetative stages only during a short period of the year. Most of the time is spent dormant or quiescent as thick-walled resting cysts with very low metabolic activity. By summarizing findings from an iterative series of research projects investigating different parts of the sexual life cycle, a more complete picture of the role of the sexual stages emerges, illuminating the consequences of life cycle within the environmental context. Gametes, the sexual stages, are formed at the end of the growing season in response to environmental signals which remain largely unknown. Gametes have lower cell-specific density and different swimming behavior compared to vegetative cells. Specifically, vegetative cells perform daily vertical migrations; whereas, gametes accumulate in patterns influenced by lower cell-specific density, changed swimming behavior, and attraction to each other. The patterns and patches of accumulated gametes (sexually induced cells) aggregate into larger and larger patterns. Together with large-scale hydrographic water movements, such as upwelling, water stratification, and fronts, cells originating from a low vegetative cell density background distribution assemble and become concentrated within a constricted space, thus forming a dense "bloom." This process is distinctly different from the paradigm of blooms resulting from simple, vegetative cell divisions. Undisturbed blooms of cyst-producing dinoflagellate gametes end with gamete fusion into diploid zygotes that transform into resting cysts. The resting cysts sink according to shape and cell-specific density into the silt fraction of the sediment. Cyst preservation depends upon the oxygenation level of the sediment and the presence of fauna. Hypoxic/anoxic conditions lower cyst mortality from benthic grazers. The reestablishment of motile, vegetative cells occurs under seasonally favorable conditions, and successful population growth depends upon environmental conditions, such as weather and nutrient availability. Factors that increase HAB risks of resting cyst-producing dinoflagellates are eutrophication leading to high cell numbers and high cyst preservation in hypoxic benthic zones. Hydrographic factors causing increased cell accumulation also are important, and intensified water stratification can amplify encystment success. These insights underscore mechanisms by which climate change is affecting HAB ecology and subsequent effects upon marine and coastal fisheries and aquaculture. [ABSTRACT FROM AUTHOR]

Anthropogenic particles (AP), which include microplastics and other synthetic, semisynthetic, and anthropogenically modified materials, are pollutants of concern in aquatic ecosystems worldwide. Rivers are important conduits and retention sites for AP, and time series data on the movement of these particles in lotic ecosystems are needed to assess the role of rivers in the global AP cycle. Much research assessing AP pollution extrapolates stream loads based on single time point measurements, but lotic ecosystems are highly variable over time (e.g., seasonality and storm events). The accuracy of models describing AP dynamics in rivers is constrained by the limited studies that examine how frequent changes in discharge drive particle retention and transport. This study addressed this knowledge gap by using automated, high‐resolution sampling to track AP concentrations and fluxes during multiple storm events in an urban river (Milwaukee River) and comparing these measurements to commonly monitored water quality metrics. AP concentrations and fluxes varied significantly across four storm events, highlighting the temporal variability of AP dynamics. When data from the sampling periods were pooled, there were increases in particle concentration and flux during the early phases of the storms, suggesting that floods may flush AP into the river and/or resuspend particles from the benthic zone. AP flux was closely linked to river discharge, suggesting large loads of AP are delivered downstream during storms. Unexpectedly, AP concentrations were not correlated with other simultaneously measured water quality metrics, including total suspended solids, fecal coliforms, chloride, nitrate, and sulfate, indicating that these metrics cannot be used to estimate AP. These data will contribute to more accurate models of particle dynamics in rivers and global plastic export to oceans. Practitioner Points: Anthropogenic particle (AP) concentrations and fluxes in an urban river varied across four storm events.AP concentrations and fluxes were the highest during the early phases of the storms.Storms increased AP transport downstream compared with baseflow.AP concentrations did not correlate with other water quality metrics during storms. [ABSTRACT FROM AUTHOR]

Introduction: Heterotrophic protists colonizing microbial mats have received little attention over the last few years, despite their importance in microbial food webs. A significant challenge originates from the fact that many protists remain uncultivable and their functions remain poorly understood. Methods: Metabarcoding studies of protists in microbial mats across high-altitude lagoons of different salinities (4.3-34 practical salinity units) were carried out to provide insights into their vertical stratification at themillimeter scale. DNA and cDNA were analyzed for selected stations. Results: Sequence variants classified as the amoeboid rhizarian Rhogostoma and the ciliate Euplotes were found to be common members of the heterotrophic protist communities. They were accompanied by diatoms and kinetoplastids. Correlation analyses point to the salinity of the water column as a main driver influencing the structure of the protist communities at the five studied microbial mats. The active part of the protist communities was detected to be higher at lower salinities (<20 practical salinity units). Discussion: We found a restricted overlap of the protist community between the different microbial mats indicating the uniqueness of these different aquatic habitats.On the other hand, the dominating genotypes present inmetabarcoding were similar and could be isolated and sequenced in comparative studies (Rhogostoma, Euplotes, Neobodo). Our results provide a snapshot of the unculturable protist diversity thriving the benthic zone of five athalossohaline lagoons across the Andean plateau. [ABSTRACT FROM AUTHOR]

Studies of stream macroinvertebrates traditionally use sampling methods that target benthic habitats. These methods could underestimate biodiversity if important assemblage components exist outside of the benthic zone. To test the efficacy of different sampling methods, we collected paired reach‐wide benthic and edge samples from up to 10 study reaches in nine basins spanning an aridity gradient across the United States. Edge sampling targeted riparian‐adjacent microhabitats not typically sampled, including submerged vegetation, roots, and overhanging banks. We compared observed richness, asymptotic richness, and assemblage dissimilarity between benthic samples alone and different combinations of benthic and edge samples to determine the magnitude of increased diversity and assemblage dissimilarity values with the addition of edge sampling. We also examined how differences in richness and assemblage composition varied across an aridity gradient. The addition of edge sampling significantly increased observed richness (median increase = 29%) and asymptotic richness (median increase = 173%). Similarly, median Bray–Curtis dissimilarity values increased by as much as 0.178 when benthic and edge samples were combined. Differences in richness metrics were generally higher in arid basins, but assemblage dissimilarity either increased or decreased across the aridity gradient depending on how benthic and edge samples were combined. Our results suggest that studies that do not sample stream edges may significantly underestimate reach diversity and misrepresent assemblage compositions, with effects that can vary across climates. We urge researchers to carefully consider sampling methods in field studies spanning climatic zones and the comparability of existing data sets when conducting data synthesis studies. [ABSTRACT FROM AUTHOR]

The EU Water Framework Directive requires monitoring of the ecological status of lakes, with fish as a relevant class of biotic quality indicator, but monitoring fish populations in large lakes is demanding. This study evaluated use in Lake Constance of a novel multi-mesh gillnet modified to reduce catch numbers. In direct comparison with conventional European Committee for Standardization (CEN) nets we achieved 48% reduction in fish mortality with 38% less labour for tasks directly influenced by fish catch numbers, while maintaining comparable species composition and catch per unit effort. Comparison of mesh sizes indicated no significant reduction in species detection in area-reduced panels of the small mesh sizes, while total observed species richness was greater when using the modified nets. Differences in benthic species communities among depth strata were common, while those of pelagic zones were more homogeneous and did not differ significantly with depth. Catches of different net types from the same depth stratum did not exhibit significant differences. The dominance structure of the most common species, relevant to lake assessment, was similar in catches of both net types, suggesting overall superiority of the modified nets in Lake Constance. Sampling conducted according to standard European CEN protocol, while deploying 60% fewer nets, yielded sufficiently precise abundance estimates for monitoring shallow areas of the benthic zone. A 50% difference in the abundance of dominant species was detected among sampling events with a certainty of 95%. The sample did not provide comparable accuracy in deep benthic strata or the pelagic zone, but was adequate to record complete inventories of species present. Based on this trial data, a new stratified sampling design is proposed for monitoring large lake fish communities for ecological assessment. Depth-dependent fish communities were used to calculate the required number of nets, which resulted in a 69% reduction for the entire lake compared to the CEN calculation method. Using the modified nets increases the feasibility of performing WFD surveys, by reducing effort and cost, while the simultaneous halving of fish mortality minimises the negative impact of fish surveys. [ABSTRACT FROM AUTHOR]

Extreme environments enable the study of simplified food-webs and serve as models for evolutionary bottlenecks and early Earth ecology. We investigated the biodiversity of invertebrate meiofauna in the benthic zone of the Great Salt Lake (GSL), Utah, USA, one of the most hypersaline lake systems in the world. The hypersaline bays within the GSL are currently thought to support only two multicellular animals: brine fly larvae and brine shrimp. Here, we report the presence, habitat, and microbial interactions of novel free-living nematodes. Nematode diversity drops dramatically along a salinity gradient from a freshwater river into the south arm of the lake. In Gilbert Bay, nematodes primarily inhabit reef-like organosedimentary structures built by bacteria called microbialites. These structures likely provide a protective barrier to UV and aridity, and bacterial associations within them may support life in hypersaline environments. Notably, sampling from Owens Lake, another terminal lake in the Great Basin that lacks microbialites, did not recover nematodes from similar salinities. Phylogenetic divergence suggests that GSL nematodes represent previously undescribed members of the family Monhysteridae—one of the dominant fauna of the abyssal zone and deep-sea hydrothermal vents. These findings update our understanding of halophile ecosystems and the habitable limit of animals. [ABSTRACT FROM AUTHOR]

A rich larger foraminifera assemblage from the Eocene carbonates of the south Sabzevar region (Now-Deh section) in central Iran indicates a late Ypresian to early Lutetian age. Nine species of Alveolina d’Orbigny are studied for systematics and biostratigraphy. The assemblage includes A. minuta, A. decastroi, A. cremae, A. cremae elongata, A. decipiens ayrancensis, A. celali, A. rugosa, A. cuspidata, A. frumentiformis. We have also found nummulitids (genus Nummulites and Assilina) and orthophragmines identified as N. campesinus, N. praediscorbinus, A. placentula, A. praespira, A. reicheli, A. ex. intrec. laxispira-maior and Discocyclina archiaci bartholomei. The recovery of Alveolina cremae elongata, A. decipiens ayrancensis, A. celali, A. rugosa, A. cuspidata and Assilina praespira has permitted for the first time to extend their geographical distribution outside of the classical peri-Mediterranean area to the central Tethys regions. The obtained biostratigraphy points to the Shallow Benthic Zones SBZ11 to SBZ13, indicating the occurrence of a Lower-–Middle Eocene carbonate system. Part of the age model is supported by the calcareous nannofossil biostratigraphy that belong to the NP14b and CNE8 biozones, recorded from the central portion of the studied section. Issues regarding the application of the SBZ into the Middle East domains are discussed in terms of relative stratigraphic position and biogeographic dispersal of some significant Alveolina species. [ABSTRACT FROM AUTHOR]

We used macrozoobenthos data (abundance, biomass, and community structure) spanning 69 years including annual surveys from 1997 to 2016 in three connected lakes with different trophic states located in the north-west of Belarus (lakes Naroch, Myastro, and Batorino) to investigate the relationships between Carlson's trophic state indices (TSI) and macrozoobenthos. We studied the response of the macrozoobenthos both over time and by depth zone. We found that there is an inverse relationship between lake productivity as measured by chlorophyll-based TSI and macrozoobenthos abundance and biomass both when comparing the three Narochianskie lakes and in the long-term dynamics within each lake. Lake-wide and littoral zone benthic biomass decreased significantly with increasing trophic state. Macrozoobenthos community structure also differed among lakes, with Chironomidae dominating in the most productive lake (Batorino), Chironomidae and Mollusca dominating in Lake Myastro, which had an intermediate trophic state, and Mollusca dominating in the lake with the lowest TSI (Naroch). We found significant differences both in the average benthos biomass and in the composition of macrozoobenthos between the profundal (silt and lack of macrophytes) and littoral zones (presence of macrophytes) within each lake. We argue that bottom substrates, macrophytes, and dreissenid mussels were more important for macrozoobenthos than trophic state in these lakes. Several benthic invertebrate taxa differed among lakes and are potential indicators of trophic state. [ABSTRACT FROM AUTHOR]

Rhodaliids, a specific family of siphonophores inhabiting the benthic zone, have remained enigmatic due to their rarity and elusive nature. These unique organisms, primarily found in open ocean habitats, exhibit distinctive features and are characterized by complex structures. During the Red Sea Decade Expedition, two rhodaliid specimens were collected at the sea bed at water depths of 438 and 495 meters. Regardless of challenges in specimen preservation, detailed morphological analysis revealed unique characteristics. Genetic analysis, employing the 16S rRNA marker, revealed one specimen closely related to Thermopalia taraxaca, while the taxonomic traits of this specimen suggested the identification of Archangelopsis jagoa. While most of the morphological features of the second specimen were also very similar to A. jagoa, some differences in coloration suggest the discovery of either an unusual colour variant or a potential new species within this genus. Notably, this study reports the first sequencing of A. jagoa. This species demonstrated a capacity to thrive in low-oxygen environments, challenging conventional assumptions about their habitat requirements. Despite difficulties in specimen handling and genetic analysis limitations due to a lack of comprehensive data, this research sheds light on the elusive world of benthic rhodaliids. [ABSTRACT FROM AUTHOR]

Benthic cyanobacteria research in high mountain reservoirs remains limited, mainly due to their complexity and knowledge gaps that persist in relation to their ecology in tropical regions. This study aimed to explore the composition, diversity, and toxic potential of cyanobacterial in the upper sediment of two Colombian reservoirs. Our investigation involved multiple methodologies, such as germination experiments, that allowed us to assess the presence and viability of cyanobacteria in upper sediment samples, while the competitive ELISA assay allowed for the quantification of toxins within the cultures. The molecular analysis of Operational Taxonomic Units (OTUs) from subsamples of sediment cultures focused on evaluating cyanobacterial diversity and richness among prokaryotic phyla, and the Phylogenetic analysis of culturable cyanobacteria. Chlorophyll-a measurements confirmed the presence of viable populations in sediment cultures, while microscopic identification demonstrated the growth capacity of cyanobacteria from the orders Nostocales, Chroococcales, Oscillatoriales, and Synechococcales under controlled laboratory conditions. Despite low microcystin levels in culture, the prior detection of mcy genes in direct sediment samples suggests a possible toxic potential of cyanobacterial inhabiting the upper sediments. Community analysis, based on the OTUs abundance, revealed a notably diverse microbial community in both reservoir sediments, with a higher relative abundance of cyanobacteria compared to other prokaryotic phyla. These findings support the hypothesis that surface sediments play a fundamental role as a repository for cyanobacteria that may pose inherent risks to ecosystem health. In conclusion, this research underscores the necessity of further studies to achieve a holistic comprehension of benthic cyanobacteria dynamics in high-mountain tropical reservoirs. [ABSTRACT FROM AUTHOR]

Middle Eocene formations of the western part of the Isparta Angle contain abundant larger benthic foraminifera (LBF). Twelve species belonging to the genus Alveolina, including A. callosa, A. fragilis, A. aff. fusiformis, A. gigantea, A. cf. gigantea, A. hottingeri, A. kieli, A. levantina, A. nuttalli, A. cf. obtusa, A. stipes, and A. tenuis have been identified throughout the two measured sections from Dinar and Çardak (SW Türkiye). The investigated assemblages, consisting also of nummulitids, orthophragminids, textulariids, rotaliids, and miliolids, allow us to assign the Suçıkan section to shallow benthic zone 13 (SBZ13) and the Karabayır section to SBZ17. Based on the biogenic associations and carbonate textures, four major facies types (MFTs), as Alveolina-soritid packstone-rudstone, Alveolina-nummulitid packstone-rudstone, nummulitid packstone-rudstone, and nummulitid-orthophragminid packstone-rudstone have been distinguished. Facies characteristics of these MFTs and the transitions between them point to a shallow-marine depositional environment ranging from inner to middle-ramp settings. [ABSTRACT FROM AUTHOR]

Understanding trait selection factors is vital for decoding the processes shaping species' assemblages. However, trait-based studies in freshwater crustacean copepod assemblages are scarce, especially in groundwater environments. We explored how environmental filtering influences functional traits in copepod assemblages across four freshwater habitats (an alluvial aquifer, a hyporheic zone, a stream benthic zone and a lake littoral) along a depth gradient. Each habitat had distinct environmental templates based on light, temperature and dissolved oxygen. We analysed 4898 individuals from 43 copepod species and examined 12 morphological and life history traits. The results revealed significant differences in copepod traits among habitats, notably in ovigerous female biomass, egg biomass and ovigerous female percentages. Furthermore, despite some statistical uncertainty, notable differences were also observed in the number of juveniles, male-to-female abundance ratios and overall biomass. No significant differences were observed in juvenile biomass, egg characteristics, body size dimorphism or juvenile-to-adult ratios among habitats. The trait variations offer insights into copepod-mediated ecosystem services, particularly carbon recycling. To gain a deeper understanding of copepod adaptations to environmental features and anthropogenic changes, future research should consider additional functional traits, such as locomotion and feeding habits. [ABSTRACT FROM AUTHOR]

The present research is a comparative study on the prevalence of parasites in marine finfish among the two major marine zones; namely the pelagic zone and benthic zone. The objectives of the present study were to investigate the parasite prevalence in both zones, as well as to determine the effect of differing marine zones regarding the presence of parasites in fish. A total of 30 individual fish occurring in pelagic and benthic zones were randomly selected from three different fishmongers at a wet market in Bintulu, Sarawak. Both the gill and stomach content of the samples were examined to detect the presence of parasites. Nematodes and trematodes were observed in the intestinal tract of the fish, Cymothoa exigua was found attached to the fish tongue, and monogenean parasites were also detected on the gills. The prevalence of the parasite was roughly equal in Setipinna breviceps, Ilisha megaloptera, and Selaroides leptolepis. The highest prevalence of parasites (87.50%) from fish in the benthic zone based on fish size was for fish measuring between 20.1 - 30.00 cm in total length (P-value=0.3778), whereas for pelagic fish, the highest prevalence of parasites (100%) in fish measurements of 30.1 - 40.0 cm in total length (P-value=0.0044). A major factor for the diversity of marine fish parasites occurring in the different zones is the difference in feeding behavior of the hosts and depth distribution which resulted in low or high rates of parasite infestation. [ABSTRACT FROM AUTHOR]

Objective: Streamflow is a primary determinant of fish assemblage structure in riverine systems, but alteration of natural flow regimes can result in fish assemblage shifts through the process of environmental filtering. Because natural drought conditions reduce and homogenize streamflow in a manner comparable to projections for climate change in some regions, drought could serve as a proxy for expected future flow conditions. Methods: We investigated the effects of drought as a temporally dynamic environmental filter of the occurrence of two guilds of fishes, benthic spawners that deposit adhesive ova along the benthic zone of rivers and pelagic spawners that release semibuoyant, nonadhesive ova into the pelagic zone of rivers. We developed species‐specific random forest models to estimate annual probability of occurrence for three benthic‐spawning and four pelagic‐spawning minnow species at three sites in the upper Brazos River, Texas, for the period 1950–2018. We then used a generalized additive mixed‐effects model to assess the relationship between drought intensity and likelihood of occurrence to test whether reproductive modes differed in response to drought (hypothesis 1) and whether response to drought was spatially (hypothesis 2) or temporally (hypothesis 3) variable. Result: We found support for hypothesis 1 as two of four pelagic‐spawning species (Shoal Chub Macrhybopsis hyostoma, Smalleye Shiner Notropis buccula) declined and two of three benthic‐spawning species increased as drought intensified, support for hypothesis 2 as responses to drought varied by gauge location, and no support for hypothesis 3 as drought response was consistent for periods 1950–1979 and 1980–2018. Conclusion: These findings offer insight into the future of riverine fish assemblages as climate change is expected to exacerbate regional drought conditions. Management of pelagic‐spawning fishes during extreme drought in the southern Great Plains may require strategies such as (1) rescues of fish from drying reaches, (2) captive holding and propagation, and (3) assisted recolonization following subsidence of drought conditions. Impact statementExtreme drought caused a temporal increase in occurrence of benthic‐spawning fishes and decrease in occurrence of pelagic‐spawning fishes. Management to conserve imperiled pelagic‐spawning fishes should consider the effects of drought even within otherwise suitable habitats. [ABSTRACT FROM AUTHOR]

The Miocene strata of the Qom Formation from the Ghalibaf section, Central Iran (NW Semnan) documented a high diversity of shallow-marine microfacies. These deposits in the Ghalibaf section, with a total thickness of 445 m, are characterized by twenty-one microfacies. The carbonate microfacies are deposited into five facies belts, including a lagoon, upper slope, lower slope, platform-margin sand shoals and margin facies. The presence of barrier reefs, intraclasts, oncoids, and grainstone aggregates, along with the absence of vast tidal flat areas, are distinguished. According to the aforementioned evidences, these sediments were deposited on a rimmed carbonate platform. In addition, the heterolithic calciturbidite deposits also show that the carbonate sequences were sedimented on a rimmed carbonate platform. Based on the available data of sequence stratigraphy analysis, seven third-order depositional sequences are bounded by type-1 and type-2 sequence boundaries. The relative sea-level changes between the upper and lower sequence boundaries in accord with the global sea-level curves reveal a reasonable correlation. However, some differences in other sequence boundaries might be due to local tectonic activities in the Qom Formation sedimentary basin, thereby leading to local sea-level changes. Moreover, biostratigraphic data based on the larger foraminifera index markers, including Praebullalveolina curdica, Borelis melo, Dendritina rangi, Meandropsina iranica, Elphidium sp. 14, Neorotalia viennoti, and Miogypsina sp. suggests the Miocene Shallow Benthic Zones, SBZ24-SBZ25 equivalent to the late Aquitanian-Burdigalian timespan. [ABSTRACT FROM AUTHOR]

Mayflies are important as macroinvertebrates of aquatic ecosystems and are reliable bioindicators of water quality. Most mayfly nymphs feed by scraping algae from underwater rocks or by extracting food particles in the littoral and benthic zones of the water bodies. The mayfly Povilla (Languidipes) taprobanes originally described from Sri Lanka was observed in plastic lined ponds in coastal Karnataka. Not only, this is the first report of the species from Karnataka, but the unique case making behaviour of this species is also described for the first time. Additionally, the species was found damaging plastic tarpaulins of 750 gsm thickness used as lining for water storage in the tank by chewing. This chewing behaviour was responsible for damage of plastic sheets leading to water leakage. The possible loss caused and a need of alternate strategies to store water is discussed. [ABSTRACT FROM AUTHOR]

Oceanic trenches are an important sink for organic matter (OM). However, little is known about how much of the OM reaching the hadal region derives from the sunlit surface ocean and other sources. We provide new insight into the OM sources in the Atacama Trench by examining the elemental and stable isotope composition of carbon and nitrogen in bulk OM throughout the entire water column and down to bathyal and hadal sediments. Moreover, we estimated the particulate organic carbon (POC) concentration and downward carbon flux. Our results, based on two‐way variance analysis, showed statistical differences in δ15NPON between the epipelagic zone and the deep zones. However, no statistical differences in δ13CPOC and C:N ratio between hadalpelagic and shallower pelagic zones were found, except for δ13CPOC in the oxygen‐deficient zone. On the contrary, whereas the isotopic signatures of hadal sediments were distinct from those over the entire water column, they were similar to the values in bathyal sediments. Thus, our results suggest that bathyal sediments could contribute more OM to hadal sediments than the different zones of the water column. Indeed, whereas POC flux estimates derived from remote sensing data indicate that ∼16%–27% of POC could evade surface remineralization within the top 200 m and potentially be exported to depths beyond the mesopelagic region, model estimates suggest that ∼3.3% of it could reach hadal depths. Our results provide a quantitative baseline of pelagic‐benthic coupling which can aid in assessment of carbon cycling changes in future climate scenarios. Plain Language Summary: Hadal trenches (>6,000 m) represent the deepest part of the ocean and are an important sink for organic matter (OM). This OM is an important energy source for heterotrophic microbes living in hadal sediments and consequently for the recycling of nutrients. However, the mechanisms of how this material reaches the hadopelagic zone as well as the relative contributions from diverse sources remain poorly understood. The carbon and nitrogen stable isotope compositions of bulk OM have been widely used to elucidate the relative contribution of OM sources in the ocean. However, few studies have evaluated the isotopic composition of particulate organic matter from surface waters all the way to the hadopelagic region and surface hadal sediments. We conclude that whereas the hadopelagic water column receives <12% of OM from the sunlit shallow ocean, only ∼3% reaches the hadal benthic zone, which receives a larger contribution from downslope sediment transport. Our results provide new insights in the cycling of carbon between the upper and deep ocean, which can assist with the forecasting of potential changes under progressive climate forcing. Key Points: The deep‐sea waters of the Atacama Trench display bulk isotopic signatures in the particulate organic matter (POM) similar to those in the epipelagic zoneThe bulk and stable isotope composition of POM in surface bathyal and hadal sediments is distinguishable from the one in the water columnA stable isotope model suggests that hadal sediments may receive more organic matter from shallower‐water sediments than from the water column [ABSTRACT FROM AUTHOR]

The radiation of bioturbation during the Ediacaran–Cambrian transition has long been hypothesized to have oxygenated sediments, triggering an expansion of the habitable benthic zone and promoting increased infaunal tiering in early Paleozoic benthic communities. However, the effects of bioturbation on sediment oxygen are underexplored with respect to the importance of biomixing and bioirrigation, two bioturbation processes which can have opposite effects on sediment redox chemistry. We categorized trace fossils from the Ediacaran and Terreneuvian as biomixing or bioirrigation fossils and integrated sedimentological proxies for bioturbation intensity with biogeochemical modeling to simulate oxygen penetration depths through the Ediacaran–Cambrian transition. Ultimately, we find that despite dramatic increases in ichnodiversity in the Terreneuvian, biomixing remains the dominant bioturbation behavior, and in contrast to traditional assumptions, Ediacaran–Cambrian bioturbation was unlikely to have resulted in extensive oxygenation of shallow marine sediments globally. [ABSTRACT FROM AUTHOR]

Three key Paleocene deep-sea sections cropping out in northern Italy contain intercalations of calciturbiditic, larger foraminifera-bearing beds derived from shallow water environments. The reconstructed Southern Alps record obtained by splicing the three sections allowed a direct correlation of the shallow benthic SB and calcareous nannofossils CN Zones, leading new data about the Shallow Benthic biozonation for the Danian-Thanetian interval and proposing four new SBP (Shallow Benthic Paleocene) Zones (SBP1-4). Such revision relies on an innovative biostratigraphic approach based on larger foraminiferal biohorizons instead of marker species according to the traditional approach used since the introduction of the SB Zones. Based on our study, the SBP1/SBP2 boundary turns out to be about 2 Ma after the K/Pg crisis, highlighting a quite fast recovery of the complexity among foraminifera. [ABSTRACT FROM AUTHOR]

Here, we revise and update the biostratigraphy of larger foraminiferal assemblages in three sections of the Priabonian Sanetsch Formation in the Helvetic Nappes of theWestern Swiss Alps: The Sex Rouge (SE) and the Sanetsch Buvette (SA) sections in the Wildhorn Nappe Complex, and the Col des Essets (ETS) section in the most external Morcles Nappe. In the SE and SA sections, the Tsanfleuron and most of the Pierredar Limestone members of the formation are assigned to SBZ 19 (early Priabonian), while the uppermost part of the formation is assigned to SBZ 20 (late Priabonian). In the external ETS section the entire Sanetsch Formation contains assemblages characteristic of SBZ 19, suggesting an earlier, middle-late Priabonian onset of the hemipelagic Stad Formation (“Globigerina Marls”). Since it was established in 1998, the Shallow Benthic Zones (SBZ), a biozonation based on larger foraminifera, has been a useful tool in the biostratigraphy of the Paleogene. Biozonation proposals for the late middle-late Eocene are based mainly in biometrical subdivision of lineages of nummulitids and orthophragmines, which requires measurements in oriented sections of isolated specimens. Here, we define previously unreported taxa from the Sanetsch Formation, which are considered characteristic for the Priabonian. They are easy to identify in random sections and thus useful biostratigraphical markers. We also describe a new orthophragminid genus, Virgasterocylina n. gen. (Orbitoclypeidae) characterized by the presence of rods, radial thickenings of calcite along ribs; a new species of Rotorbinella, R. epardi n. sp., and a new genus and new species of difficult suprageneric attribution, Sanetschella indeprensa n. gen., n. sp. We add the new taxa to the larger foraminiferal association characterizing the Priabonian (SBZ 19–20). The revision of the literature, together with our own sample collections revealed that these new taxa occur in Priabonian rocks from different basins in the western Tethys. Virgasterocylina n. gen. also occurs in the Caribbean bioprovince in the middle and upper Eocene. In the western Tethys, Virgasterocylina ferrandezi is subdivided into two subspecies, V. f. ferrandezi (Özcan and Less) and V. f. lessi n. ssp., which characterize the SBZ 19 and 20 biozones respectively. [ABSTRACT FROM AUTHOR]

Eocene larger benthic foraminifera including orthophragmines, nummulitids and alveolinids from the Jahrum and Pabdeh formations in the Zagros region are presented. The studied 20-m-thick stratigraphic interval contains, Asterocyclina Gümbel 1870, Nemkovella Less 1987, Orbitoclypeus Silvestri 1907, Discocyclina Gümbel 1870, Nummulites Lamarck 1801, Assilina d’Orbigny 1826 and Alveolina d’Orbigny 1826. This larger benthic foraminiferal assemblage testifies for the shallow benthic zones (SBZs) 15 to 17, which ranges from the middle Lutetian up to the early Bartonian. Further micropaleontological analysis made on intercalated planktonic-rich levels helps calibrate the larger foraminifera biostratigraphy, demonstrating a correlation with the E11 biozone. This confirms that the chronostratigraphic calibration of the SBZs made by previous authors for the peri-Mediterranean area can, through the middle Lutetian to the early Bartonian, be applicable in the Middle East as well [ABSTRACT FROM AUTHOR]

Abiometrical study on four reticulate Nummulites populations from the lower part of Asmari Formation of the Vazag section (Zagros zone) is carried out. The biostratigraphy obtained by studing the succession points to the Early Oligocene (Rupelian), indicating shallow benthic zones SBZ21 and SBZ22A by the occurrence of Operculina cf. complanata, Eulepidina formosoides, Nephrolepidina sp. The age assignment is calibrated with calcareous nannofossils biostratigraphy indicating the NP22–NP23 (=CNO2–CNO3) Zones. We have observed a stratigraphic trend related to Nummulites bormidiensis Tellini 1888 that results to be characterized by two populations composed of transitional Nummulites fichteli/bormidiensis with values of mean inner proloculus that exceeds by very little the boundary commonly established at 300 µm. Such a populations, indicated as Nummulites ex interc. bormidiensis et fichteli, span through the lower Rupelian where classically just N. fichteli is reported so far. The stratigraphic distribution ofNummulites bormidiensisis and related transitional forms is here stretched to the Rupelian (SBZ21 and SBZ22A), encompassing older ages than previously recorded throughout the Neo-Tethys Ocean. [ABSTRACT FROM AUTHOR]

Paleogene sedimentary deposits are exposed in several localities along the extended Thrace Basin in the Greek territory. One of the best sites in terms of preservation, richness and type of sediment occurs along the coastline of Fanari village (SW of Komotini city). Two outcrops, which consist of upper Eocene shallow marine clastic sediments, were sampled to analyze the full spectrum of larger benthic foraminifera (LBF) that comprises a rich and diverse assemblage of orthophragmines (Discocyclina, Orbitoclypeus and Asterocyclina), nummulitids (Nummulites, Assilina, Operculina, Heterostegina and Spiroclypeus), and other benthic taxa (e.g., Silvestriella, Pellatispira, Fabiania, Sphaerogypsina, etc.). Adetailed systematic description of LBF from Fanari is presented, which refines the biostratigraphic age of SBZ (Shallow Benthic Zone) 20 corresponding to the late Priabonian for the whole sequence. Twenty-four taxa among which six at (chrono)subspecies level belonging to twelve genera were identified and morphometrically analyzed for the first time from Greece. The LBF assemblage is characterized by the constant presence of Nummulites fabianii almost throughout the whole sequence. The most abundant species are Pellatispira madaraszi and Spiroclypeus carpaticus, though they occur in the upper part of the sequence along with orthophragmines. The foraminiferal distribution in the sequence enables paleoenvironmental observations and the reconstruction of the evolution of the Fanari area. Three main depositional marine shelf facies are distinguished at the shallow upper foreslope of the carbonate platform, making the Fanari section a key area not only of latest Priabonian but also of outer shelf biofacies. [ABSTRACT FROM AUTHOR]

Previous studies provided evidence of the mixing of boreal–tropical cladocerans (Crustacea) in the Far East of Eurasia, as well as the presence of numerous pre-Pleistocene relict endemics. In this study, we hypothesize that the colonization history is reflected in the proportions of endemic/boreal/tropical taxa among different habitat types within this region. We analyzed 442 qualitative samples collected from seven sub-regions of the Far East of Russia and South Korea along a latitudinal transect of approximately 2200 km, where we identified 101 Cladocera species. Our results showed a significantly higher proportion of endemic taxa in the plankton compared to the littoral and benthic zones. The proportions of endemic/boreal/tropical taxa in the permanent and temporary waters were similar. We observed a distinct shift in dominance in benthos and littoral zone across our transect: boreal taxa were prevalent in the northern sub-regions (1–4), while tropical taxa were prevalent in the southern sub-regions (5–7), with a pronounced boreal–tropical transition zone (sub-regions 4–5). Our findings suggest that this pattern arose due to the unhindered dispersion of the two faunas in a latitudinal direction until they met at the boundary during their arrival in the Late Pleistocene. In contrast, the proportions of the boreal and tropical taxa in plankton did not exceed 16% in any of the studied sub-regions, and the proportion of boreal taxa decreased from 16% to 10%, while that of the tropical taxa increased from 0% to 10% from north to south. We propose that the lower proportions and the absence of mixing of fauna in the plankton can be explained by the strong presence (sometimes dominance) of relics that occupy these water bodies before the arrival of colonizers from the north and south. Our findings highlight the significant role of biotic interactions in the formation of biogeographic boundaries, which was previously underestimated. [ABSTRACT FROM AUTHOR]

This paper is devoted to studying the spreading speed determinacy to an abstract time-periodic monotone semiflow, which is of monostable type with weak compactness and admits boundary equilibria in the phase space. The problem is challenging due to the existence of single spreading speed or multiple spreading speeds (fastest and slowest spreading speeds). We first study under what condition single spreading speed exists and establish necessary and sufficient conditions for linear and nonlinear selections of the spreading speed as well as the minimal wave speed of traveling wavefronts. In the case of multiple spreading speeds, the determinacy of each speed is further investigated based on the connection of wavefronts to the boundary equilibria. We apply our results to five time-periodic models: a delayed diffusive equation, a stream population model with a benthic zone, a nonlocal dispersal Lotka-Volterra model, and two cooperative systems. [ABSTRACT FROM AUTHOR]

The Pontils fossil site (middle Eocene, Ebro Basin, Spain) includes several vertebrate-bearing levels situated in a sequence recording a continental to marine transition. Although the locality has been known since the 1980s and scarce mammal remains have been already documented, an intensive sampling has not been developed until now. This work presents the first results of the recent field campaigns carried out at this site. Seven levels have yielded significant vertebrate remains, revealing a diverse assemblage which includes chondrichthyans, actinopterygians, amphibians, crocodilians, squamates, metatherians, eulipotyphlans, apatotherians, chiropterans, rodents, artiodactyls, perissodactyls, and primates, besides other non-vertebrate fossils. The Pontils assemblage indicates a mangrove swamp environment with warm and humid conditions and increasing marine influence towards the top of the sequence. Among mammals, primates are particularly diverse, including abundant remains of a minuscule, still undetermined omomyiform, and scarce teeth of Pseudoloris, Necrolemur, and an undetermined anchomomyin. The occurrence of larger benthic foraminifera allows the assignment of Pontils to Shallow Benthic Zone 17 (Bartonian), solving the debate about the age of the locality, previously assigned either to the Bartonian or the Lutetian. These data, together with previous magnetostratigraphic analyses, allow correlation to chrons C18r or C18n.1r, constraining the age of Pontils to between 39.58 and 41 Ma. Therefore, the Pontils site represents a new reference section for the correlation of marine and continental biostratigraphy during the middle Eocene. [ABSTRACT FROM AUTHOR]

This study was designed to examine the impacts of ark shell Scapharca subcrenata enhancement and suspended oyster Crassostrea sikamea farming on sediment properties and fauna communities in the benthic zone of Xiangshan Bay, China. Ark shell enhancement took place over 319 days, after which sediment samples were collected from each of the three treatment sites: the enhancement area, an oyster farm, and a control area. Sediments from the oyster farming area had significantly higher moisture and acid volatile sulfide content, and the highest Cu, Zn, Pb, and Cd concentrations in all three treatment areas. The ark shell enhancement area has the lowest total organic carbon. No significant difference was found between the mean grain size in each of the three areas. Benthic fauna communities in the ark shell enhancement area were similar to those in the control area. Among the 16 faunal taxa identified, Ruditapes philippinarum was the most abundant species, followed by Glycera onomichiensis and Musculus senhousia. Suspension feeders were not found in the sediment beneath the oyster rafts. Cluster analysis showed a distinct separation between the benthic fauna communities in the oyster farming area and the other two treatment areas. Ark shell enhancement was thus shown to have minimal impact on the benthic environment, while the raft-farmed oysters had significant effects on the sediment structure and the benthic fauna after more than ten years of farming. The differences between the impacts of ark shell enhancement and oyster farming could be attributed to the slowing of water flow caused by oyster rafts. [ABSTRACT FROM AUTHOR]

Traditionally, most of our understanding of lake zooplankton dynamics is from data collected in the pelagic, open water zone. However, the littoral and benthic zones of lakes can play a role in zooplankton community interactions and relationships. Utricularia spp., or the bladderworts, inhabit littoral and shallow waters of lakes and consume zooplankton. Limited information exists on the dietary habits of bladderworts and how diet varies across lakes and seasonally. Bladderwort dietary assemblage in two Michigan, USA, lakes was quantified during the thermally stratified period of 2020, and was compared to zooplankton in the adjacent water column. Bladderwort trap size was positively related to zooplankton prey size, but not number of prey consumed or taxa richness. Bladderworts consumed a variety of prey, the majority dominated by littoral cladoceran and ostracod taxa. Seasonal change was observed, with significantly higher ostracod dominance earlier in the season, shifting into cladoceran dominance later in the season. Ostracods were more commonly found in traps than the water column, whereas Cladocera were more commonly found in the water column than the traps. These results shed light into the dietary habits of bladderworts, which can have consequences for food web dynamics and energy transfer in small lake systems. [ABSTRACT FROM AUTHOR]

This article presents the findings of a research project conducted in the Santos Basin, Brazil, which aimed to collect comprehensive oceanographic data for future environmental management in offshore oil and gas regions. The study examined various aspects of the benthic and pelagic environments, including physical, chemical, sedimentological, and biological factors. The research findings are categorized into methodological aspects, hydrographic conditions, pelagic ecosystems, and benthic ecosystems. The ultimate goal of the project is to balance sustainable oil and gas exploration with the preservation of regional biodiversity and environmental health. The article also discusses the study of meiofauna and the use of machine learning techniques to identify distinct benthic zones with unique environmental conditions. Additionally, the study highlights differences in macrofauna and foraminifera between the northern and southern sectors of the slope. The implementation of ecosystem-based management (EBM) in the Santos Basin faces challenges such as distinguishing natural variability from human-mediated changes and involving relevant stakeholders. However, it is crucial to base EBM on high-quality scientific data to ensure the long-term preservation of marine ecosystems. [Extracted from the article]

This study aims model the distribution of meiofauna indicators in relation to environmental variables from the Santos Basin continental margin, SE Brazil, using machine learning techniques, to provide baseline information and foster future monitoring programs. A total of 100 sampling stations were distributed in eight transects and 11 isobaths (25 to 2,400 m) perpendicular to the coast. In each station, three replicates were sampled for meiofauna and 38 environmental parameters. A total of 28 meiofauna taxa were found, with a mean richness varying from 3 to 15 taxa per station. Meiofauna mean density varied between 55 and 2,001 ind. 10 cm-2. Density of meiofauna and its most frequent taxa (Nematoda, Copepoda, Kinorhyncha, and Polychaeta), and taxa richness were used as descriptors for the models. Meiofauna and nematode density showed the highest training and testing accuracies, with R2 values above 0.74. Based on the distribution of meiofauna descriptors and their responses to environmental conditions, we suggest a mosaic of six benthic zones. The La Plata Plume zone and the Cabo Frio Upwelling zone are two of the most diverse and productive zones in the continental shelf, wich are separated by the less productive Central Continental Shelf zone. A fourth zone, with very low meiofauna densities, corresponds to the carbonated sediments of the shelf-break. The Upper and Mid-Slope is a narrow zone along the entire basin, with intermediate densities and small amounts of high-quality organic carbon. The largest, impoverished zone, the Lower Slope and Plateau comprises the deepest areas and the São Paulo Plateau. The study showed that, although some zones can be recognized by most meiofauna descriptors, others are better characterized by specific ones, implying that meiofauna indicators should be monitored concomitantly. We recommend the optimization of sampling design based on our model to reduce costs and increase our understanding of the system. [ABSTRACT FROM AUTHOR]

A population of large-shell brachiopods belonging to Stricklandia lens lens from the lower Silurian Solvik Formation is exposed in a capstone layer covering approximately 300 m2 on steeply dipping strata along the shores of Engervannet at Sandvika in the Oslo Region of southern Norway. Based on sample counts, a density estimated at 250 to 350 articulated shells per square meter resulted from crowding during growth. Given that the former sea bed on which the brachiopods settled can be traced over a lateral distance of 60 m with an average width of 5 m, it is calculated that a monospecific population exceeding 90,000 brachiopods matured from a single, extensive spat fall. Related large-shell brachiopods from the lower Silurian of North America, including Virgiana decussata, Pentamerus oblongus, P. palaformis, and Pentameroides subrectus are commonly preserved in growth position, but observed pavements rarely exceed more than 0.25 m2 in size. Articulated shells within those populations are almost always truncated midway above the beak and hinge area due to post-mortem erosion by submarine scour. In contrast, the horizon with Stricklandia shells from Sandvika is enormous in scope and features many whole individuals pushed into a more recumbent position in the same direction by a marine current. Re-orientation of the steeply inclined limestone layer to a horizontal position suggests that such a current flowed from the present-day southwest to the northeast as it swept over the Silurian sea bed. [ABSTRACT FROM AUTHOR]

Environmental data is crucial for planning, permitting, execution and post construction monitoring of marine renewable energy projects. In harsh conditions in which marine renewable energy is harvested, integrated monitoring platforms comprising multibeam imaging sonar systems coupled with other sensors can provide multiparametric data of the marine environment surrounding marine renewable energy installations. The aim of this study was to test the possibilities of observing the occurrence of fish and marine mammals using a multibeam imaging sonar system deployed at a wave power test site. The results obtained from a ten-day data set proved the platform as suitable for long time underwater monitoring and also revealed that the occurrence of fish and marine mammals was distributed across characteristic time and space domains. Large fish [>0.4 m] frequently occurred at night-time and near the benthic zone. Small fish [<0.2 m] frequently occurred during daylight and within the pelagic zone. The occurrence of seals was periodically distributed along a daily cycle, with intervals of 1–2 hours between maxima and minima. In conclusion, the use of multibeam imaging sonar can be a reliable technique for the qualitative and quantitative observations of fish and marine mammals in general and at marine renewable energy sites specifically, including protected and economically important species. [ABSTRACT FROM AUTHOR]

The importance of fish species in ichthyocenes of the benthic zone (up to a depth of 2000 m) in the Russian part of the Far Eastern seas and adjacent waters of the Northwest Pacific is discussed for the first time. The study is based on the data of bottom trawl surveys conducted by the Pacific Research Institute of Fisheries and Oceanography (TINRO) in 1977–2010. The inverse Simpson's index (or polydominance index) is selected as a measure of dominance; the Sørensen–Czekanowski similarity index is used for comparative analysis of the dominance structure in ichthyocenes of the regions. The analysis of the importance of species in the ichthyocene species structure is carried out for the top 20 species ranked by biomass. These species constitute a substantial portion of the biomass of all demersal fishes in all the regions: an average of 94.9% for the shelf and 95.8% for the continental slope. A conclusion is made that the ichthyocenes of bottom and near-bottom biotopes (0–2000 m) in Russian waters of the Far Eastern Seas are represented by communities with poor evenness in species abundance and a pronounced dominance of two to four species. The importance of species in the ichthyocene structure is as follows: walleye pollock (Theragra chalcogramma) dominates all the regions; the subdominants are Pacific herring (Clupea pallasii), Pacific cod (Gadus macrocephalus), Atka mackerel (Pleurogrammus monopterygius), and Okhotsk atka mackerel (P. azonus), depending on the region. The ubiquitous dominance of walleye pollock is broken on the continental slope of the Bering Sea dominated by the giant grenadier (Albatrossia pectoralis); the group of subdominants on the continental slope of all regions is comprised of Greenland halibut (Reinhardtius hippoglossoides matsuurae), popeye grenadier (Coryphaenoides cinereus), Pacific herring, Pacific sleeper shark (Somniosus pacificus), scale-eye plaice (Acanthopsetta nadeshnyi), and blackfin founder (Glyptocephalus stelleri). The graphs of similarity between the study regions (Sea of Okhotsk, Bering Sea, Sea of Japan, and Pacific waters off Kamchatka and the Kuril Islands) in species composition and dominant species structure of ichthyocenes are composed separately for the shelf and continental slope using summarized data. [ABSTRACT FROM AUTHOR]

Burdurina selandinica Sirel from Paleocene carbonates of the Golbui section of Central Iran is reported and discussed. The stratigraphic position of foregoing succession is consistent with the previous studies depending on the faunal assemblage of the Selandian–early Thanetian, namely Sistanites iranicus Rahaghi, Anatoliella sp., Haymanella paleocenica Sirel, Coscinospira prima Schlagintweit et al., Miscellanea cf. yvettae Leppig, Elaziginadienii (Hottinger), Idalina sinjarica Grimsdale,Pachycolumella acuta Septfontaine et al., Pachycolumella elongata Septfontaine et al., Rotospirella conica (Smouth). After the latest reorganization on Shallow Benthic Zones (SBZs) of the Paleocene, two stages correspond to SBZ3. Three predominant microfacies types including coral-coralline algal framestone, bioclastic foraminiferal-peloidal grainstone-packstone and coral floatstone were recognized in the studied section. The microfacies gradients within the succession and paleoenvironmental analysis suggest deposition in a shallow-marine ramp environment that is located in a global carbonate platform stage I from the middle paleolatitude. [ABSTRACT FROM AUTHOR]

This study investigates the changes in paleoenvironmental conditions in the northern branches of the Neo-Tethys by employing geochemical proxies and shell data of larger benthic foraminifera (LBF) located in central Cappadocia. Three measured stratigraphic sections are studied from the Altipinar Formation (Boztepe Member), which is dated as middle Eocene. Three genera and five specieswere recorded as a result of the paleontological analyses, namely, Alveolina sp., Assilina exponens, Nummulites aturicus, Nummulites maximus and Nummulites perforatus. Composed of clayey sandy limestones, the Boztepe Member is represented by SBZ (Shallow Benthic Zones) 16-17 (late Lutetian/early Bartonian). In the Cappadocia region, a warming event was characterized by a temperature increase of 3°C to 4.5°C, and the warming started after 41.0 Ma (younger than the Lutetian /Bartonian boundary). The peak warming occurred around 40.0 Ma (early Bartonian). This period corresponds to the Middle Eocene Climatic Optimum (MECO), which was a significant global warming event. The findings of this study are confirmed by numerous studies that the global warming event occurred in the middle Eocene (between 41.8 and 39.7 Ma.). Additionally, while paleoenvironmental changes had no effect on the shell shape of Assilina exponens, they had a significant effect on the shell shape of Nummulites perforatus. The diameter/thickness ratio of benthic foraminifera tends to be smaller in shallowconditions than in deep conditions. Thiswas observed as their shell shapes becamemore spherical. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are concerning emerging pollutants. Here, MPs in four edible aquatic species of different trophic levels (between ∼2 and 4), including fish species Esox lucius (Esocidae: Esocinae); Cyprinus carpio (Cyprinidae: Cyprininae); and Luciobarbus caspius (Cyprinidae: Barbinae); and the swan mussel Anodonta cygnea (Unionidae), were assessed in the Anzali freshwater ecosystem. It is a listed wetland in the Montreux record. MPs were extracted from gastrointestinal tracts (GI), gills, muscles, and skin. All the studied fish and mussels (n = 33) had MPs. MP fibres, fragments and sheets were detected in every GI examined, however, fibres were the only type of MPs in skins, muscles and gills and were the most abundant MP. The MPs found in the fish and mussels were mainly made of nylon (35% of the total MPs), polypropylene-low density polyethylene (30%), and polycarbonate (25%). The average numbers of MPs found in every fish specimen, expressed per wet body mass, had a moderate negative correlation with the condition factor (K) (MP/g - K: Pearson correlation r = −0.413, p = 0.049), and there was no significant relation with the growth factor (b) (r = −0.376; p = 0.068). Importantly, Luciobarbus caspius (with trophic level 2.7–2.8) bioaccumulated MPs and presented a strong correlation between their MP contamination and age (r = 0.916 p < 0.05). Greater gill mass (or related factors) played an important role in the accumulation of MPs, and there was a strong correlation between these factors for Esox lucius and Cyprinus carpio (r = 0.876; r = 0.846; p < 0.05 respectively). The highest MP/g gills (1.91 ± 2.65) were in the filter feeder Anodonta cygnea inhabiting the benthic zone. Esox lucius (piscivorous, trophic level 4.1) was the most contaminated species overall (a total of 83 MPs in 8 individuals, with 0.92 MP/g fish), and their gills where MPs mainly accumulated. Cyprinus carpio was the most contaminated specimen (MPs in specimens), while the number of MPs per mass unit increased with the trophic level. Their feeding and ecological behavior in the aquatic habitat affected the level of accumulation. This work includes evidence of translocation of MPs within the aquatic organisms. [Display omitted] • Speciments had up to 44 fragment MPs, Cyprinus carpio was the most contaminated by them. • The greatest frequency of MP/g, fibres, was in the gills of Anodonta cygnea. • Luciobarbus caspius bioaccumulated MPs in older individuals. • The number of MPs per gram of wet fish tissue increased with the trophic level. [ABSTRACT FROM AUTHOR]

Orogenesis plays a crucial role in creating, modifying, and disrupting sediment routing fairways. Reconstructing past source to sink systems is a critical step to unravel the geological history, mandatory to disentangle tectonic and climatic forcings, and to understand the perturbations that affected the overall system. The Paleocene-Eocene period is a debated early stage of the early Pyrenean orogeny, characterized by the piggy-back style tectonic partitioning of sub-basins as the deformation front propagates towards the southern foreland. An important issue is to understand how sedimentary systems reacted and reorganized in response to this dynamic scenario. and whether the stratigraphic and sediment provenance results align with the envisioned scenario. In this paper we aim at contributing to the paleogeographic, sedimentologic and tectono-sedimentary evolution of the South-Pyrenean foreland basin by reviewing the chronostratigraphic framework of the basin infill in its south-central sector (the Ager sub-basin in the Serres Marginals thrust sheet). We built five new magnetostratigraphic sections, which together encompass most of the Paleogene record, aimed to best reconcile magnetostratigraphic data with the defined biostratigraphic framework of the region including marine Shallow Benthic Zones (SBZ biozones) and continental mammalian localities (MP levels). Detailed trends in subsidence show the development and evolution of the foreland depozones, from forebulge to foredeep and wedge-top setting, relative to the successive emplacement of the Montsec and Serres Marginals thrust sheets. A correlation with the eastern portion of the foreland basin (Lower-Middle Pedraforca and Cadí Thrust Sheets) and adjacent northern Graus-Tremp basin (Montsec Thrust Sheet) was feasible and seeks to contribute to the tectono-sedimentary evolution of the South-Pyrenean foreland in the light of a source to sink approach. Our proposal includes a new paleogeographic evolution of the area in a series of paleogeographic maps from Late Thanetian to Late Cuisian times. • A Tectonosedimentary and paleogeographic evolution of the South Pyrenean foreland from Palaeocene to Lutetian times. • Pyrenean sourced sedimentary systems were routed from the eastern Pyrenees on the upper thrust sheets at the Eocene period. • Post PETM sea-level rise at 55.5 My (Ilerdian marine flooding) contributed to a reorganization in the sediment routing systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • The distribution of benthic macroinvertebrates is largely affected by temperature. • The sediment permeability varies significantly with the increasing biomass of benthic macroinvertebrates. • The mixed bioturbation mode of various benthic macroinvertebrates was better than the bioturbation mode of single-type benthic macroinvertebrates in improving sediment permeability. Water quality, aquatic habitat, and groundwater recharge, which have a critical impact on the river ecosystem health, are associated with the vertical hydraulic conductivity of streambed (K v). Macroinvertebrates bioturbation can generate heterogeneity in the benthic and hyporheic zones to influence K v by particle reworking and burrow construction, which are directly and indirectly related to the physicochemical conditions of sediments. However, understanding how these factors and processes influence K v and its role is deficient. Here the spatial distribution of benthic macroinvertebrates and its effects on K v in the Weihe River were investigated. Macroinvertebrate bioturbation had a significant effect on K v when the biomass was greater than 1 mg/m2, and yet when the biomass exceeded 102 mg/m2, bioturbation had a significant inhibitory effect on K v as the result of clogging due to the fine sediment particles and secrete mucus produced by benthic Macroinvertebrates. Macroinvertebrate distribution and biomass are often influenced by temperature which could also decrease the fluid viscosity, thus improving K v. Moreover, the mixed bioturbation mode with the predominated Tubificidae was better than the bioturbation mode of single-type benthic macroinvertebrates in improving sediment permeability. These findings have important implications for revealing the disturbance mechanism of benthic macroinvertebrates on K v and provide a reliable theoretical basis for the protection and planning of river ecosystems. [ABSTRACT FROM AUTHOR]

Subsurface sediments offer an important refuge that support the survival and persistence of river invertebrates during adverse surface conditions. Access to refuges for invertebrates varies with differing hydrological and substrate characteristics, especially the proportion of fine sediment. This study examines whether substrate characteristics influence the use of the hyporheic zone as an invertebrate refuge during a fine sediment disturbance event. We used 12 outdoor stream mesocosms to examine the vertical migration of benthic and hyporheic invertebrates to fine sediment loading. Each mesocosm was filled with coarse or experimentally colmated sediments. After 69 days, a fine sediment pulse of three varying fine sediment concentrations was added to the stream mesocosms. Both before and after the fine sediment pulse, a distinct gradient in the abundance and richness of hyporheic invertebrates was apparent with depth. Hyporheic abundance and taxonomic richness decreased at 5 cm and increased at 18 cm during fine sediment loading, indicating vertical migration of invertebrates from the benthic to hyporheic zone. Our study provides support for the hyporheic zone as a refuge for benthic invertebrates during fine sediment disturbance events. We also found evidence that movement pathways within subsurface sediments were still accessible and permitted bidirectional migration of individuals between the benthic and hyporheic zone in the coarse and colmated sediments during fine sediment loading. Understanding how increased fine sediment deposition affects streambed porosity will be increasingly important with ongoing climate change and anthropogenic sedimentation. [ABSTRACT FROM AUTHOR]

We aimed to determine the effects of water level and habitat heterogeneity on gastropod fauna in the littoral zone, and the differentiation of functional feeding guilds (FFG) of gastropods. Two periods were analyzed: 2012 (low water level, LWL) and 2013 (high water level, HWL) in the littoral zone of two shallow waterbodies (Sutla backwater, NW Croatia). Waterbody S1, covered with Ceratophyllum demersum, was sampled in the macrophyte stands, and the littoral benthal area, while waterbody S2, without macrophytes, was sampled only in the littoral benthal area. It was observed discovered that among the macrophyte stands in S1, gastropods were significantly more abundant during LWL. The same trend was observed in the littoral benthal area of S2. In contrast, gastropod abundance was higher in the littoral benthal area of S1 during HWL. Comparing gastropods in the two waterbodies, the abundance in S1 was ten times higher than in S2. The most abundant species was Gyraulus parvus, which accounted for 51–92% of the gastropods observed among the macrophytes of S1 and 86% in the adjacent benthic zone. Among the FFG groups, grazers (particularly those feeding on gymnamoebae and rotifers) had the largest proportion, followed by shredders feeding on small pieces of macrophytes. In our research, we indicate the important role of microhabitat diversity and submerged macrophytes as a rich food source for gastropods and safe shelter from predators. [ABSTRACT FROM AUTHOR]

Decomposition of allochthonous organic matter is an essential process in headwater streams. Damming of streams alters decomposition rates in the benthic zone downstream, but little is known about the effects on hyporheic decomposition. We examined the effects of dams on hyporheic and benthic organic matter decomposition, using the cotton-strip assay over five seasons, in two forest mountain streams in western Japan. The decomposition rates in the hyporheic zone were lower downstream of the dams than at the unregulated reach in spring, rainy season and fall, but they did not differ in winter and summer. Hyporheic decomposition rates were comparable to the benthic rates in one river and were lower in the other river. Decomposition rates did not differ between coarse- and fine-mesh bags in many seasons at all sites, and the densities of macroinvertebrates were low, suggesting that the contribution of macroinvertebrate to decomposition in the hyporheic zone was small. These results showed that the hyporheic zone is an important zone for decomposition and that presence of dams altered the hyporheic decomposition in some seasons. Thus, it is crucial to examine both the benthic and hyporheic zones when addressing the effects of dams and reservoirs on stream ecosystem processes. [ABSTRACT FROM AUTHOR]

An important shallow marine deposit is described and illustrated with focus on the systematics and biostratigraphy of larger foraminifera from three stratigraphic sections of the Becirman Formation from the Batman and Siirt regions (Southeastern Turkey). A quite diverse association, mostly dominated by rotaliids (11 species belonging to 7 genera) and subordinate porcelaneous and agglutinated taxa, is documented as well. The fossil assemblage, including Elazigina dienii, Rotospirella conica, Praelockhartia cf. neoakbari, Cuvillierina cf. sireli associated with Mardinella daviesi and Idalina sinjarica, indicates the late Danian SBZ2. The abundance of rotaliids is linked, in this time frame, to the recovery of the shallow benthic communities after the K/Pg extinction including increase of surface water temperatures and oligotrophy. This was possibly due to the climatic warming recorded at the end of the Danian (Latest Danian Event), thus promoting a rapid adaptative radiation of rotaliids at genus rank. [ABSTRACT FROM AUTHOR]