Biotic Composition Research Articles

Influence of heavy metal exposure on gut microbiota: Recent advances.

Gut microbiota plays a functionally important part in retaining the homeostasis of host physiology, however, under exposure of various heavy metals, the composition of gut biota is disturbed in relation to species diversity and richness. Ever since the increase of microbiome-related studies during the last decade, many research studies have delivered an understanding of the reasons and concerns of gut microbiota-related modifications. During the past decade, it's been confirmed from various studies that heavy metals poisoning alters the microbial composition, which results in changes in gene expression, alteration in metabolism, immunity, neurological dysfunction, and causes various other disorders. The present comprehensive review is summarizing an attempt to enumerate the key findings from recent clinical or preclinical studies related to the influence of heavy metals on gut microbiota published recently. Google, PubMed, Science Direct, Scopus, and Google Scholar were employed as primary search engines using the keywords such as "heavy metals, gut microbiota, dysbiosis, and intestinal microbiota" for finding relevant research articles from the past 10 years and some old important articles. Here, we tried to provide insight into some of the key timelines and scientific findings from reported literature, like the effects of heavy metals such as arsenic, cadmium, lead, and mercury on the general body and specifically on the gut microbiota of different model organisms. So, it is important to increase awareness against heavy metal-induced toxicity and formulate guidelines for the benefit of the environment.

Life support systems and aquatic communities in public aquariums

The Pangandaran Integrated Aquarium and Marine Research Institute (PIAMARI) was developed in Pangandaran, and is equipped with public aquarium facilities. The Main Aquarium is an oceanarium in the form of a box, with a volume of 1.238 million liters, and accommodates various marine biota. This paper aims to provide an overview of the life support system used and the aquatic communities in the Main Aquarium. An inventory of principal components and equipment, the composition of biota, plankton, and ectoparasites was conducted in the oceanarium. The Main Aquarium is supported by filtration using a sand filter, protein skimmer, and an ozone generator. Water quality is maintained using the filtration combined with partial water changes. There are nine species of fish, including sharks and rays, and two species of turtles that are kept in the oceanarium, where most of the collections are omnivores, with IUCN LC conservation status and the rest NT to CR. Seven plankton genera were identified in the oceanarium (H’:1.78 and E: 0.90). There was Cryptocaryon ectoparasite infestation on the gills and skin of Trachinotus blochii with open lesions. Fish collections show different behavior and consume the fresh and artificial feed. Apart from being an edu-tourism facility, the oceanarium can act as a place for living and ex-situ culture for endangered marine biota.

Exploring the distribution of the non-native Umbra pygmaea across European freshwater ecoregions through climatic suitability and locally consumed diet

The East American mudminnow Umbra pygmaea was introduced to Europe a century ago and is now established in at least six European countries. Although considered harmless and with low spread potential, this fish species shows potential to colonise a broad range of habitats due to its wide environmental tolerance. Stomach content analyses were conducted over 3 years to obtain a first insight into this species' diet, which could indicate the potential to alter the biotic composition of recipient ecosystems. The results showed that this fish can potentially have a high impact on insects, fish, and even amphibians through predation. Species distribution models further indicated that environmental conditions of Central European ecoregions are currently a limiting factor for the spread of this species which seems, at least for now, to be driven by anthropogenically driven introductions. Considering the species’ potential to be invasive and impact native biota, monitoring of potential spread is recommended.

Macrolichen Communities Depend on Phorophyte in Conguillío National Park, Chile.

The community composition of epiphytic macrolichens from two tree species (Araucaria araucana and Nothofagus antarctica) was conducted in temperate forests in the Conguillío National Park, Chile. The composition of lichen biota is influenced by phorophyte species, bark pH, and microclimatic conditions. A total of 31 species of macrolichens were found on A. araucana and N. antarctica. Most of the species showed phorophyte preference, with nine being exclusive to A. araucana and 10 to N. antarctica. The detrended correspondence analysis (DCA) indicated the formation of three communities: one representing macrolichens growing on N. antarctica and two others growing chiefly on A. araucana, either with north or south exposure. More work is needed to study the lichen biota of the forests of the Chilean Andes, which are under multiple threats, including clearing and climate change. In order to counteract such risks to native forests and to the biodiversity of the associated epiphytic lichens, conservation plans should be established that consider the factors that influence the composition of the lichen community.

Counteracting effects of soil biota on emergence and growth of herbaceous plants

BackgroundPlants condition the biotic composition of their rhizosphere. In turn, this plant legacy on the soil biota may affect the performance of plants recruiting in their vicinity. Unravelling how plant-soil legacies drive plant recruitment is key to understand vegetation dynamics and plant community assembly. Studies on the topic usually focus on the effects of soil microbiota as a whole, while the relative role of different guilds of soil organisms in the plant recruitment processes is not usually dissected.AimsHere, we used soils of Mediterranean woody plant species to test whether arbuscular mycorrhizal fungi (AMF) and small-size microbiota (< 50 µm) (MB) affect the germination success and growth of eight herbaceous plants.ResultsWe documented a significant increase in seedling emergence probability when small-sized MB was present and no effect of AMF. In contrast, the aboveground plant biomass decreased with the presence of MB and increased with that of AMF. Interestingly, those plants growing in the absence of MB and in soils from woody plants associated with higher AMF richness developed higher aboveground biomass.ConclusionThis study brings new evidence on how soil microbial communities can determine the performance of their associated herb community, and also, how the effects of different microbial guilds may change across the plant ontogeny. Given these results, the differential effect of soil microbial functional guilds should be considered to better understand plant soil legacies and feedbacks, potentially driving plant recruitment and community assembly.

Katian (Late Ordovician) sphinctozoan-bearing reefs: Hybrid carbonates before the glacial maximum

With a significant rise of metazoan reef-builders in shallow marine environments, the Late Ordovician saw a substantial increase in precipitation of crystalline crusts in reef systems, which may reflect a dramatic environmental change in the ocean. Isopachous crystalline crusts occur abundantly in boundstone of Katian sphinctozoan-bearing microbial reefs on the Zhe-Gan Platform, South China. These deposits are characterized by in-place carbonate textures that are interpreted as associations of abiotic, bioinduced and biocontrolled fabrics, considered here to be hybrid carbonates. Little previous work has been done to investigate how these hybrid carbonates are related to the transition in biotic composition during the Ordovician. These fabrics occur in well-preserved sphinctozoan-bearing reefs in the lower member of the Sanqushan Formation at the Jitoushan Section in Yushan County, Jiangxi Province. The meter-scale reefs are dominated by Corymbospongia, Amsassia and microbial components, and are cemented by fibrous sparry crusts. The intertwined Corymbospongia and Amsassia build the primary skeletal framework. Microbes and subsequent cementation enhance the stability of the framework by covering most of the macrofossil skeletons. The studied skeletal-microbial-cement reefs share a lot of similarities with contemporaneous reefs of North China and Central Nepal, but differ from Early Ordovician reefs, which lack sparry crusts. Our results provide evidence for extensive synsedimentary cementation on the seafloor, which could have played a crucial role in the consolidation of Late Ordovician reefs during the icehouse conditions before the Hirnantian glacial maximum.

Micro-photoautotroph predation as a driver for trophic niche specialization in 12 syntopic Indo-Pacific parrotfish species

Abstract Parrotfish are key agents of bioerosion and sediment production in coral reef ecosystems; however, their dietary targets and therefore potential sources of variation in carbonate cycling lack resolution. Here we address this knowledge shortfall in our current understanding of parrotfish diets by testing the concept that protein-rich micro-photoautotrophs are the target prey for many Scarinine parrotfishes. We focus at fine spatial scales on the feeding substrata of 12 syntopic Indo-Pacific parrotfish species at mid-shelf sites around Lizard Island, Great Barrier Reef, Australia. We followed individual parrotfish on snorkel until biting was observed, and then extracted a reef core around each bite. The surface of each bite core was scraped to ~1 mm for quantitative microscopic analysis (up to 630 × magnification) and for 16S and 18S rRNA metabarcoding. The most dominant photoautotrophic group in terms of surface cover was filamentous cyanobacteria, followed by crustose coralline algae. Epiphytic, epilithic, endophytic and endolithic filamentous cyanobacteria were consistent bite core biota. Although the density of filamentous cyanobacteria on bite cores was largely consistent among the 12 parrotfish species, the quantitative microscopic data and rRNA metabarcoding revealed distinct differences between parrotfish species in the taxonomic composition of core biota. Our data provide further evidence that these syntopic parrotfish species partition feeding resources.

The Unusual Dominance of the Yeast Genus Glaciozyma in the Deeper Layer in an Antarctic Permafrost Core (Adélie Cove, Northern Victoria Land) Is Driven by Elemental Composition.

Rock glaciers are relatively common in Antarctic permafrost areas and could be considered postglacial cryogenic landforms. Although the extensive presence of rock glaciers, their chemical-physical and biotic composition remain scarce. Chemical-physical parameters and fungal community (by sequencing the ITS2 rDNA, Illumina MiSeq) parameters of a permafrost core were studied. The permafrost core, reaching a depth of 6.10 m, was divided into five units based on ice content. The five units (U1-U5) of the permafrost core exhibited several significant (p < 0.05) differences in terms of chemical and physical characteristics, and significant (p < 0.05) higher values of Ca, K, Li, Mg, Mn, S, and Sr were found in U5. Yeasts dominated on filamentous fungi in all the units of the permafrost core; additionally, Ascomycota was the prevalent phylum among filamentous forms, while Basidiomycota was the dominant phylum among yeasts. Surprisingly, in U5 the amplicon sequence variants (ASVs) assigned to the yeast genus Glaciozyma represented about two-thirds of the total reads. This result may be considered extremely rare in Antarctic yeast diversity, especially in permafrost habitats. Based on of the chemical-physical composition of the units, the dominance of Glaciozyma in the deepest unit was correlated with the elemental composition of the core.

Hydrogen cyanide, a key plant defense, as a potential driver of root-associated nematode communities along urbanization gradients

IntroductionPlant chemical defenses can influence the distribution, community composition, and abundance of soil biota. Urbanization plays a key role in shaping soil biotic communities either directly through changes in soil properties or indirectly via changes in plant characteristics such as defense traits. The effects of urbanization and plant defenses on the abundance and structure of aboveground plant-associated communities have been studied, yet their effects on belowground root-associated communities are poorly understood.MethodsHere we sampled white clover (Trifolium repens L.) leaves and roots along urban–rural gradients in the cities of Antwerp and Ghent, Belgium. We measured production of hydrogen cyanide (HCN) in leaves, a known defense trait against herbivores, and abundances of different feeding guilds of nematodes associated with the roots.ResultsWe found that HCN production decreased with increasing levels of urbanization in both cities. Urbanization was significantly correlated with shifts in root-associated nematode community structure in Antwerp but not in Ghent. Responses of nematode feeding guilds and trophic groups to urbanization were highly dependent on the clovers’ HCN production, especially in Ghent. Changes in nematode channel ratio in Antwerp indicated that urban root-associated nematode communities of white clover were more strongly dominated by fungivorous nematodes.DiscussionOur results demonstrate that urbanization is driving changes in a plant phenotypic trait and in the community structure of root-associated nematodes, as well as that both changes interact. Plant defense mechanisms could thus help elucidate the effects of urbanization on root-associated biota communities. As strong differences existed between the two studied cities, the particular properties of cities should be taken into account to better understand the direction and strength of phenotypic trait changes driven by urbanization.

The Perturbation of Mangla Watershed Ecosystem in Pakistan Due to Hydrological Alteration

Hydrological regimes influence an aquatic ecosystem’s biotic composition, structure, and functioning. But construction of dams or anthropogenic activities substantially alter the hydrologic regimes. In this study, we used a method named as the “Indicators of Hydrologic Alteration” to examine the degree of hydrologic alteration at seven flow gauge stations in the Mangla watershed. The assessment of alteration is carried out according to the Range of Variability (RVA). This method relies on analyzing hydrologic data obtained from existing measurement points (e.g., stream gauges) within an ecosystem or model-generated data. We used 33 parameters categorized into 5 groups based on magnitude, duration, frequency, timing, and rate of change to characterize hydrologic variation within a year statistically. We then examine the hydrologic perturbations by comparing the measure of central tendency and dispersion for each parameter between the “pre-impact (1967–1994)” and “post-impact (1995–2014)” periods. The results show that within the Mangla watershed, the high alteration was noted in the magnitude of monthly flows and extreme flows at Azad Pattan, Gari Habibullah, Palote and at Muzafarabad stations. The flow at Domel and Kohala stations are found in low hydrological alteration among all groups of indicators. The study indicates that Neelum Basin at Muzaffarabad has significantly high alteration with maximum negative values. On the other hand, a high frequency of alteration observed in the monthly flows and extreme water conditions. Overall, a moderate alteration is observed in the whole watershed, which may produce adverse effects on the aquatic ecosystem of the Mangla watershed.

Emerging contaminants in the aquatic environment: phytoplankton structure in the presence of sulfamethoxazole and diclofenac.

Chemicals from anthropogenic activities such as domestic sewage, pesticide leaching, and improper chemical disposal have caused groundwater contamination. The presence of these emerging contaminants in the aquatic environment can change water quality and biota composition. Thus, this study investigates the effect of two emerging contaminants, anti-inflammatory drug diclofenac (DCF) and antibiotic sulfamethoxazole (SMX), on the aquatic environment, evaluating the phytoplankton community structure. A microcosm experiment was conducted with 16 sampling units, each one with 500 mL of water sample containing phytoplankton exposed to these drugs at different concentrations (0.1, 0.5, and 1.0 mg L-1). The experiment lasted 15 days, and samples were collected on days 0, 3, 5, 7, and 14 to evaluate the phytoplankton community, the concentrations of the drugs, and the nutrients in the samples. Six phytoplankton groups were identified, and diatoms and green algae were the most diverse and abundant groups. For the entire community, we identified differences between the days of the experiment, varying in the diversity and density of organisms, but not between the concentrations of the two drugs. Evaluating the groups separately, we identified differences in the abundance of cyanobacteria for the treatment with diclofenac and desmids for the treatment with sulfamethoxazole. We demonstrated that the presence of pharmaceuticals in freshwater ecosystems can somehow affect the phytoplankton community, especially the diversity and abundance of cyanobacteria and desmids. Therefore, our study indicates the importance of evaluating the presence of pharmaceuticals in freshwater ecosystems and their influence on aquatic organisms, as well as pharmaceuticals may be changing the structure of the aquatic environment.

Elevated O3 Exerts Stronger Effects than Elevated CO2 on the Functional Guilds of Fungi, but Collectively Increase the Structural Complexity of Fungi in a Paddy Soil.

Global climate change is characterized by altered global atmospheric composition, including elevated CO2 and O3, with important consequences on soil fungal communities. However, the function and community composition of soil fungi in response to elevated CO2 together with elevated O3 in paddy soils remain largely unknown. Here we used twelve open-top chamber facilities (OTCs) to evaluate the interactive effect of CO2 (+ 200ppm) and O3 (+ 40ppb) on the diversity, gene abundance, community structure, and functional composition of soil fungi during the growing seasons of two rice cultivars (Japonica, Wuyujing 3 vs. Nangeng 5055) in a Chinese paddy soil. Elevated CO2 and O3 showed no individual or combined effect on the gene abundance or relative abundance of soil fungi, but increased structural complexity of soil fungal communities, indicating that elevated CO2 and/or O3 promoted the competition of species-species interactions. When averaged both cultivars, elevated CO2 showed no individual effect on the diversity or abundance of functional guilds of soil fungi. By contrast, elevated O3 significantly reduced the relative abundance and diversity of symbiotrophic fungi by an average of 47.2% and 39.1%, respectively. Notably, elevated O3 exerts stronger effects on the functional processes of fungal communities than elevated CO2. The structural equation model revealed that elevated CO2 and/or O3 indirectly affected the functional composition of soil fungi through community structure and diversity of soil fungi. Root C/N and soil environmental parameters were identified as the top direct predictors for the community structure of soil fungi. Furthermore, significant correlations were identified between saprotrophic fungi and root biomass, symbiotrophic fungi and root carbon, the pathotroph-symbiotroph and soil pH, as well as pathotroph-saprotroph-symbiotroph and soil microbial biomass carbon. These results suggest that climatic factors substantially affected the functional processes of soil fungal, and threatened soil function and food production, highlighting the detrimental impacts of high O3 on the function composition of soil biota.

Biostromal unit from the Middle Devonian Jinbaoshi Formation, Sichuan, Southwest China: Implications for ecological structure of coeval reef communities

This study provides a comprehensive palaeontological and palaeoecological analysis of a middle Givetian (Middle Devonian) coral-stromatoporoid biostromal unit from the upper member of the Jinbaoshi Formation, northern Sichuan Province, Southwest China. The biostromal unit is 17.7 m of medium- to thick-bedded limestones, and lacks observable morphological relief in the field. Diverse shallow marine benthic fossils are common elements of the biostromal unit encompassing stromatoporoids (7 genera), tabulate corals (4 genera), brachiopods (2 genera), plus unidentified rugose corals, chaetetids, bryozoans, tubeworms, ostracods, gastropods, crinoids and calcimicrobes. In terms of the biotic composition and biostrome-building contributors, three ecological units are recognized: Alveolites–Clathrocoilona community (EU 1), Salairella–Pseudotrupetostroma community (EU 2) and Scoliopora–Idiostroma community (EU 3). High fragmentation of bioclasts partially with micritic envelopes in wackestone, packstone to grainstone matrix and the dominance of low-profile stromatoporoids indicate deposition in shallow water conditions with episodic high sedimentation rate and frequent turbulent periods. Muddy silt- to sandstone facies overlie the biostromal unit, and are interpreted to represent a shallowing-up sequence, together with terrigenous input, thus triggering termination of the biostromal unit. This biostromal unit is similar to the other early to middle Givetian reefs of South China, East Australia, West Europe, East Europe and North Africa in relation to their fossil composition and reef-building characteristics. The stability of the reef communities (i.e. no conspicuous extinction) and common occurrence of unusual reef structures (e.g. coverstone) are thus interpreted as significant biotic factors for the expansion of large-scale ecosystems during the Phanerozoic reef-building acme.

Diversity and putative metabolic function of prokaryotic communities in tank bromeliads along an elevation gradient in tropical Mexico.

Tank bromeliads are unique canopy microhabitats that offer freshwater and organic nutrient-rich substrates in the Neotropics. In them it is possible to thoroughly characterize environmental factors and species composition of terrestrial and aquatic biota. Therefore, these plants have been used as natural models to study how communities are distributed and assembled. Here we used amplicon sequencing of the 16S rRNA gene and their functional annotations to study the diversity and metabolic potential of prokaryotic communities in tank bromeliads in five different forests along an elevation gradient in tropical Mexico. Furthermore, we analyzed the effects of vegetation type and environmental factors inside the tanks on prokaryotic composition. We found a high prokaryotic diversity in tank bromeliads along the elevation gradient. Prokaryotes commonly observed in acidic environments rich in organic carbon, and the potential pathogen Pasteurella multocida, were present in all samples, but few amplicon sequence variants were shared between forests. The prokaryotic composition was affected by forest type, and comparisons against null models suggest that it was shaped by non-neutral processes. Furthermore, prokaryotic community changes significantly covaried with tank water temperature, pH, and inorganic carbon. We found a high diversity of putative metabolic groups dominated by chemoheterotrophs and fermenters, but taxonomic groups involved in nitrogen and sulfur cycling were also present in all samples. These results suggest that tank bromeliads promote taxonomic and metabolic diversity of the prokaryotic community at a local and regional scale and play an important role in the biogeochemistry of forest canopies in the Neotropics.

Paeonol Ameliorates Ulcerative Colitis in Mice by Modulating the Gut Microbiota and Metabolites.

Ulcerative colitis (UC) is a chronic recurrent inflammatory disease of the gastrointestinal tract. Recent studies demonstrate that the phenolic tannin paeonol (Pae) attenuates UC in mouse models by downregulating inflammatory factors. However, its molecular mechanism for UC treatment has not been explored from the perspective of the gut microbiota and metabolomics. In this study, we investigated the effects of Pae on colonic inflammation, intestinal microbiota and fecal metabolites in 3% dextran sodium sulfate (DSS) induced BALB/c UC mice. Pae significantly improved the clinical index, relieved colonic damage, reduced cytokine levels, and restored the integrity of the intestinal epithelial barrier in UC mice. In addition, Pae increased the abundance of gut microbiota, partially reversed the disturbance of intestinal biota composition, including Lactobacillus and Bacteroides, and regulated metabolite levels, such as bile acid (BA) and short-chain fatty acid (SCFA). In conclusion, our study provides new insight on Pae remission of UC.

Comparison of methods (ROV, diver) used to estimate the composition and abundance of biota colonizing an offshore oil platform: A pilot study

Offshore oil and gas platforms have a finite life of production operations. Once production ceases, decommissioning options for the platform are evaluated. The role that a platform’s jacket plays as invertebrate habitat may inform the decommissioning decision. Worldwide, few scientific surveys specific to marine invertebrates have been conducted at platforms to collect data needed for biological assessments; however, recent research has examined the biological community utilizing historical industry-collected Remotely Operated Video (ROV) imagery that was not specifically collected for such purposes. To address concerns of bias in using video footage from industry structural surveys for biological assessments, we compared estimates of invertebrate density and species richness beneath a California oil platform determined using data from three sources: video from an industry ROV “structural” survey, video from a scientific ROV “biological” survey using the same vehicle, and photoquadrat still imagery from a scientific scuba diver survey. All surveys were conducted along the same jacket crossbeams. We found that the epibenthic assemblages characterized by the two ROV methods were similar. More species were observed in the diver photoquadrats than in either of the two kinds of ROV surveys, because smaller and more cryptic species could be resolved. We cannot extrapolate from this preliminary, localized study to all platforms worldwide; however, our results indicate routine platform structural integrity surveys are as valuable as dedicated scientific biological surveys for macroinvertebrates and represent an invaluable source for opportunistic marine community assessments.

The effect of Crataegus and Berberis canopy types on bioindicators of soil quality in a semi-arid climate

Crataegus and Berberis shrublands are natively distributed in Asia, Europe, North America and Africa. Despite the widespread distribution of these two species, the effect of pure and mixed canopy composition of these species on bioindicators of soil quality has received little attention. In the current research, the effect of pure [Crataegus (PC) and Berberis (PB)] and mixed [Crataegus and Berberis with almost equal canopy cover (50C:50B), Crataegus-dominated stand (70C:30B) and Berberis-dominated stand (30C:70B)] canopy types on litter properties, soil fauna and flora communities in different depths (0–10, 10–20 and 20–30 cm) was studied in the Mazandaran province, Iran. A total of 75 litter and 225 soil samples were collected and analysed. The results of this research showed that soil micro-climate and fertility are the main drivers of the population, composition and diversity of soil biota under the studied canopy covers. Increased soil temperature commonly had adverse effects on the populations of soil biota in the study area. Accordingly, the 50C:50B canopy type with a more appropriate micro-climate (i.e., higher soil moisture and lower soil temperature) and fertile soils showed higher populations of soil organisms, especially in the topsoil (0–10 cm). It is expected that results can improve scientific approaches to better comprehend of soil functions mechanism in the different canopy covers and also help to optimize land cover structures and enhancing of ecosystem services in semi-arid regions.

Facies character and skeletal composition of heterozoan carbonates in a high-energy confined embayment (Miocene, Finale Ligure Limestone, NW Italy)

During the early and middle Miocene, diverse photozoan to heterozoan carbonate and mixed carbonate-siliciclastic depositional systems characterized the Mediterranean region at palaeo-latitudes of 30–40°N, during a time of warm climate. These systems ranged from carbonate ramp to rimmed platforms to current-swept flooded incised palaeo-valleys, seaways and straits. This study focuses on the facies character, skeletal biota composition, diagenesis and stable carbon and oxygen isotope signature of a mixed carbonate-siliciclastic succession (lower-middle Miocene Finale Ligure Limestone and underlying Oligocene-lower Miocene siliciclastic deposits) accumulated in a high-energy coastal setting (Finale Ligure, NW Italy) to improve the knowledge on the variety and controlling factors of Miocene heterozoan skeletal carbonates.The 3D reconstruction of the geometry of the early-middle Miocene Finale Ligure basin identifies an embayment, about 35 km2 wide, limited by uplifted and eroded Alpine tectonic units and connected to the open sea through a strait. The Oligocene-Miocene sedimentary succession unconformably overlying the Alpine deformed substrate consists of 14 lithofacies (L1-L14). Besides pockets of karstic breccias (L1) preceding the marine transgression, discontinuous outcrops of glaucony-bearing litharenite, siltstone, conglomerate and wackestone/packstone with planktonic foraminifera (L2-L4) represent the preserved remnants of an eroded marine shelf affected by tectonic uplift and subsequent erosion, approximately in the Aquitanian-Burdigalian, overlain through an angular unconformity by transgressive conglomerates and bioturbated litharenites (L5-L7). The onset of carbonate skeletal production characterizes the overlying compositionally mixed carbonate-siliciclastic Langhian-Serravallian Finale Ligure Limestone succession (up to 100–150 m thick, L8-L14). These cross-bedded skeletal packstone and grainstone/rudstone are composed of barnacles, echinoderms, bryozoans, bivalves, scleractinian and stylasterid corals, and lack halimedacean algae as previously published. They accumulated in a high-energy setting with strong bottom currents, driven by the amplification of tidal and/or storm currents in a confined embayment, promoting the formation of seaward prograding metre-scale subaqueous dunes.Unlike other lower-middle Miocene carbonate systems, the Finale Ligure heterozoan carbonates contain rare coralline red algae and larger benthic foraminifera but are enriched in barnacles, scleractinian and stylasterid corals. The coastal palaeo-environmental conditions, with hard rocky substrates, strong bottom currents, high nutrients and water turbidity, influenced the composition of the skeletal carbonate producers. These distinctive lithofacies character and composition resulted from the confined embayment morphology inherited from the marine flooded Alpine bedrock that was subjected to land runoff driving nutrient input.

Pleistocene glacial and interglacial ecosystems inferred from ancient DNA analyses of permafrost sediments from Batagay megaslump, East Siberia

AbstractPronounced glacial and interglacial climate cycles characterized northern ecosystems during the Pleistocene. Our understanding of the resultant community transformations and past ecological interactions strongly depends on the taxa found in fossil assemblages. Here, we present a shotgun metagenomic analysis of sedimentary ancient DNA (sedaDNA) to infer past ecosystem‐wide biotic composition (from viruses to megaherbivores) from the Middle and Late Pleistocene at the Batagay megaslump, East Siberia. The shotgun DNA records of past vegetation composition largely agree with pollen and plant metabarcoding data from the same samples. Interglacial ecosystems at Batagay attributed to Marine Isotope Stage (MIS) 17 and MIS 7 were characterized by forested vegetation (Pinus, Betula, Alnus) and open grassland. The microbial and fungal communities indicate strong activity related to soil decomposition, especially during MIS17. The local landscape likely featured more open, herb‐dominated areas, and the vegetation mosaic supported birds and small omnivorous mammals. Parts of the area were intermittently/partially flooded as suggested by the presence of water‐dependent taxa. During MIS 3, the sampled ecosystems are identified as cold‐temperate, periodically flooded grassland. Diverse megafauna (Mammuthus, Equus, Coelodonta) coexisted with small mammals (rodents). The MIS 2 ecosystems existed under harsher conditions, as suggested by the presence of cold‐adapted herbaceous taxa. Typical Pleistocene megafauna still inhabited the area. The new approach, in which shotgun sequencing is supported by metabarcoding and pollen data, enables the investigation of community composition changes across a broad range of taxonomic groups and inferences about trophic interactions and aspects of soil microbial ecology.

Ecological Heterogeneity of Oxbow and Floodplain Lakes Along the Kapuas Riverine System

Kapuas River in West Kalimantan with over 1,143 km is the largest river in Indonesia. It serves as a main refuge for high potential biodiversity. Oxbow lakes along the Kapuas River are of high ecological essential due to the number and the diversity of habitats they provide. In addition, oxbow lakes are critical components of the floodplain systems of lowland rivers. The objective of this study was to explore the diversity of oxbow lakes and their connectivity to the main river. We conducted fieldwork to measure water quality and ecological components at 12 oxbow lakes along the Kapuas River and two lakes in the Sentarum complex in January - February 2020. We measured the environmental parameters including water depth, water temperature, Secchi/transparency, pH, dissolved oxygen concentration, chlorophyll-a concentration, total nitrogen, and total phosphorus concentrations. Aquatic biota, including phytoplankton and zooplankton community structures, were also observed at 12 oxbow lakes along the Kapuas River and two lakes in the Sentraum complex. The sampling points represented both permanent and non-permanent connectivity of the oxbow lakes to the main river. The result indicates the variability of environmental characteristics between the lakes, based on water quality and biota analysis; for example, water acidity, as indicated by pH, was likely to seem like the main variable determining the oxbow lake biota. Also, the habitat connectivity of oxbow lakes to the main river has significantly influenced the biotic composition.