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Atolls islands are biogenic landforms that are intrinsically capable of adjusting their size, position, and elevation to changing sea levels. The vulnerability of atoll islands to sea level rise is not intrinsically due to their low elevation but primarily due to the loss of their island building capacity. The geophysical processes that control atoll island accretion are being impacted on global and local scales. Protecting and restoring the natural geophysical processes of atoll island accretion through local conservation actions is key to unlocking nature-based opportunities for enhancing atoll resilience to global change. Atoll islands are often perceived as inevitably lost due to rising sea levels. However, unlike other islands, atoll islands are dynamic landforms that have evolved, at least historically, to vertically accrete at a pace commensurate with changing sea levels. Rather than atoll islands' low elevation per se , the impairment of natural accretion processes is jeopardising their persistence. While global marine impacts are deteriorating coral reefs, local impacts also significantly affect accretion, together potentially tipping the scales toward atoll island erosion. Maintaining atoll island accretion requires intact sediment generation on coral reefs, unobstructed sediment transport from reef to island, and available vegetated deposition sites on the island. Ensuring the persistence of atoll islands must include global greenhouse gas emission reduction and local restoration of accretion processes. [ABSTRACT FROM AUTHOR] more...

The prospects for ecologization of technological paradigm of development in the sector of mineral resources are studied and substantiated with regard to the requirements and constraints, and based on the equal possibilities for the biosphere and technosphere. The notion of the nature-like technologies is structured subject to the coincidence of missions of the content-rich components in the natural and geotechnical systems. The methodology of the homeostatic transformation of the biological system functions into the structure of a cluster on the convergent mining technologies is presented. [ABSTRACT FROM AUTHOR] more...

Most laboratory atmospheric chamber studies probing the chemical and physical properties of secondary organic aerosol (SOA) perform such experiments with mixing ratios of volatile organic compounds (VOCs) well-above atmospheric relevance (≳50 ppbv). When performing ozonolysis of biogenic VOCs at mixing ratios of atmospheric relevance (≲10 ppbv), repeatability of replicate experiments is hindered by the limitations of conventional VOC injection techniques. To overcome these limitations, two novel components (stop/flow and split valves) were embedded in a conventional VOC injection setup, thereby permitting the use of higher VOC volumes of injection to attain low VOC mixing ratios, and the delivery of the VOC to the environmental chamber as a short, discrete pulse for subsequent reaction. Implementation of these novel VOC injection components has resulted in improvements in variability between replicate chamber experiments of up to a factor of 7 with respect to particle number, mass, and size distributions at both high and low VOC mixing ratios (50 and 10 ppbv, respectively). These improvements permit extension of quantitative measurements of SOA formation to VOC mixing ratios at or near atmospheric levels, where new particle formation (NPF) and SOA mass loading are typically within experimental variability. [ABSTRACT FROM AUTHOR] more...

Drought is a liydroclimatic extreme that causes perturbations to the terrestrial biosphere, and acts as a stressor on vegetation, affecting emissions patterns. During severe thought, isoprene emissions are reduced. In this paper, we focus on capturing this reduction signal by implementing a new percentile isoprene drought stress (yd) algorithm in NASA GISS ModelE based on the MEGANS (Model of Emissions of Gases and Aerosols from Nature Version 3) approach as a function of a photosynthetic parameter (Vc.max) and water stress (/?). Four global transient simulations from 2003-2013 are used to demonstrate the effect without yd (Default_ModelE) and with online yd (DroughtStressModelE). DroughtStressModelE is evaluated against the observed isoprene measurements at the Missouri Ozarks Ameriflux (MOFLUX) site during the 2012 severe thought where improvements in correlation coefficient indicate it is a suitable thought stress parameterization to capture the reduction signal during severe drought. The application of yd globally leads to a decadal average reduction of -2.7% which is equivalent to -14.6 Tg yr'1 of isoprene. The changes have larger impacts in regions such as the Southeast U.S. DroughtStress ModelE is validated using satellite QHCHO column from the Ozone Monitoring Instrument (OMI) and surface O3 observations across regions of the U.S. to examine the effect of drought on atmospheric composition. It was found the inclusion of isoprene drought stress reduced the overestimation of QHCHO in Default_ModelE during the 2007 and 2011 southeastern U.S. droughts and lead to improvements in simulated O3 during drought periods. We conclude that isoprene drought stress should be tuned on a model-by-model basis, because the variables used in the parameterization responses are relative to the land surface model hydrology scheme (LSM) and the effects of yd application could be larger than seen here due to ModelE not having large biases of isoprene during severe drought. [ABSTRACT FROM AUTHOR] more...

Cities are taking the lead on climate change mitigation with ambitious goals to reduce carbon dioxide (CO2) emissions. The implementation of effective mitigation policies will require accurate measurements to guide policy decisions and monitor their efficacy. Here, we present a comprehensive CO2 inventory of an urban temperate forest and unmanaged grassland using field observations. We estimate the annual storage of CO2 by vegetation and soils and place our biogenic flux estimates in the context of local fossil fuel (FF) emissions to determine when, where, and by how much biogenic fluxes alter net CO2 flux dynamics. We compare our hourly estimates of biogenic fluxes in the forest site to modeled estimates using a modified version of Urban‐Vegetation Photosynthesis and Respiration Model (Urban‐VPRM) in Washington DC/Baltimore area presenting the first urban evaluation of this model. We estimate that vegetation results in a net biogenic uptake of −2.62 ± 1.9 Mg C ha−1 yr−1 in the forest site. FF emissions, however, drive patterns in the net flux resulting in the region being a net source of CO2 on daily and annual timescales. In the summer afternoons, however, the net flux is dominated by the uptake of CO2 by vegetation. The Urban‐VPRM closely approximates hourly forest inventory based estimates of gross ecosystem exchange but overestimates ecosystem respiration in the dormant season by 40%. Our study highlights the importance of including seasonal dynamics in biogenic CO2 fluxes when planning and testing the efficacy of CO2 emission reduction polices and development of monitoring programs. Plain Language Summary: The quantification of biogenic carbon dioxide (CO2) fluxes in cities is important to developing, reporting, and testing the efficacy of greenhouse gas emission reduction policies. Yet, to date there is a lack of detailed CO2 flux inventories conducted in urban ecosystems which is hindering our abilities to advance and evaluate urban carbon cycling models. Our study characterizes how unique features of urbanization influence carbon cycling dynamics in a temperate forest and grassland and provides a critical evaluation of a model for estimating biogenic fluxes of CO2. We identify key areas of needed model development and identify the seasonal and temporal significance of biogenic fluxes relative to total CO2 fluxes (biogenic + anthropogenic sources) in our study area. Key Points: In urban landscapes, the biogenic carbon dioxide (CO2) fluxes from forest patches and grassland areas vary at fine temporal and spatial scalesThe Urban‐Vegetation Photosynthesis and Respiration Model closely approximated temporal trends in gross ecosystem exchange but overestimated ecosystem respiration in the wintertimeFossil fuel emissions drive patterns in the net flux of CO2 except in summer afternoons when biogenic fluxes dominate [ABSTRACT FROM AUTHOR] more...

A time-series observation of Asterionellopsis glacialis (Castracane) Round 1990 bloom in the surf zone of east coast of India and associated physico-chemical parameters, was carried out during pre-monsoon period (May 2018). This study also reviews the species status as a surf-zone diatom and its temporal characteristics. Referring to the earlier study, the temporal characteristic of A. glacialis bloom in Indian context can be classified as 'sporadic' due to the alteration of blooming community and may be also further investigated for its seasonality as the bloom mostly observed during the pre-monsoon season. Among the nutrients, silicate is identified as a major factor controlling the bloom of A. glacialis. The present study highlights the introduction of biogenic silica attributed to precipitation induced land runoff and the effect of wind as important environmental factors responsible for A. glacialis proliferation in nearshore waters of east coast of India. [ABSTRACT FROM AUTHOR] more...

To better understand the formation processes of biogenic secondary organic aerosols (SOAs) over remote oceanic regions, aerosol samples were collected from 2010 to 2012 at Chichijima Island in the western North Pacific (WNP). The samples were analyzed by gas chromatography‐mass spectrometry for SOA tracers, which are produced by the photochemical oxidation of biogenic volatile organic compounds (BVOCs), including isoprene, monoterpenes, and sesquitepenes. Although no seasonal trend was identified for the isoprene‐derived SOA tracers, we observed higher levels of the monoterpene‐derived and sesquiterpene‐derived SOA tracers in winter/spring and lower levels in summer/autumn. We found a significant correlation (r = 0.87) of β‐caryophyllinic acid with levoglucosan, the latter being a specific tracer of biomass burning (BB). This suggests that the β‐caryophyllene accumulated in higher plants is evaporated by BB followed by atmospheric oxidation during long‐range transport from the Asian continent over the WNP. The biogenic secondary organic carbon concentration estimated using a tracer‐based approach ranged from 0.11 to 174 ngC m−3 (avg. 34.8 ± 38.2 ngC m−3), accounting for 0.02%–32.0% (avg. 6.11% ± 6.42%) of the measured organic carbon. Our results indicate that SOAs are formed by the photooxidation of BVOCs. The backward trajectories of air masses further support their transport from the central Pacific during mid‐spring to mid‐autumn, whereas BB aerosols are transported from the Asian continent during mid‐autumn to mid‐spring over the WNP. Positive matrix factorization analyses of the SOA tracers suggest that organic aerosols of Chichijima are mostly related to BVOC emissions, with BB's additional contributions especially in winter and spring. Key Points: Monoterpene SOA tracers are significant sources for BSOAs, followed by isoprene and β‐caryophyllene SOA tracers in Chichijima aerosolsHigh‐NOx BSOA tracers (2‐MGA, 3‐HGA, and 3‐MBTCA) are influenced by the long‐range transport of anthropogenic air masses from East AsiaLow‐NOx BSOA tracers (2‐MTLs and C5‐alkenetriols) are produced mainly by the oxidation of locally emitted isoprene [ABSTRACT FROM AUTHOR] more...

The continental shelf pump is believed to be important in transporting terrestrial materials across the East China Sea (ECS). More than 300 water samples collected from the ECS and a numerical model were used to identify the cross‐shelf exchanges of dissolved aluminum (Al) in the ECS in summer. The results indicated that dissolved Al concentrations ranged from <1.0 to 242 nM, with the highest concentrations observed in the Zhe‐Min coastal waters, while the lowest concentrations were determined to be in Kuroshio deep waters. The Kuroshio surface waters receive additional dissolved Al from the ECS continental shelf through a cross‐shelf exchange process. By using dissolved Al as a tracer, evidence was found about the cross‐shelf transport of Al in the ECS. Cross‐shelf transport of dissolved Al was associated with fluctuations in the Taiwan Strait Warm Water, and the driving mechanisms were analyzed using a momentum equation. Ekman transport promoted by the summer monsoon was the key physical mechanism controlling the off‐shelf transport of dissolved Al. Quantitative calculations showed that the ECS was a net source of dissolved Al to adjacent waters, of which almost 65% of the output entered the East/Japan Sea, while the remaining 35% entered the Kuroshio currents. Our results highlight the importance of cross‐shelf transport processes to the distribution and cycling of biogenic elements within the marginal seas of China, and highlight the wider implications for biogeochemical cycles throughout the western Pacific Ocean. Plain Language Summary: In this paper, we combined field observations with numerical models to study the transport of Al‐rich coastal waters to the adjacent oligotrophic offshore waters across the ECS continental shelf during summer 2013. Evidence was found about the cross‐shelf transport behavior of dissolved Al within the ECS, and the physical mechanisms controlling the off‐shelf transport of dissolved Al across the ECS continental shelf were investigated. The results indicated that the larger cross‐shelf transport was mainly driven by the summer monsoon. The primary objective of this study was to determine the forces driving off‐shelf transport of dissolved Al from the ECS continental shelf. Calculation of the exchange fluxes of dissolved Al along the 100 and 200 m isobaths indicated that the ECS continental shelf was a net source of dissolved Al to adjacent waters. Our results show the importance of cross‐shelf transport processes in the distribution and cycling of biogenic elements within the marginal seas of China, and highlight the potential wider implications for biogeochemical cycles throughout the western Pacific Ocean. Key Points: Combined field observations and numerical simulations were used to investigate the behavior of dissolved aluminum in the East China Sea (ECS)Knowledge of processes and physical mechanisms underlying off‐shelf transport of dissolved aluminum in the ECS was acquiredQuantitative study the off‐shelf and on‐shelf exchange fluxes of dissolved aluminum across the isobaths in the ECS [ABSTRACT FROM AUTHOR] more...

Formic and acetic acids are ubiquitous in the troposphere, playing an important role in the atmospheric chemistry. Recent model studies ended up with substantial low bias on their tropospheric budgets presumably due to a large missing biogenic source derived most likely from photochemical oxidation of long-lived volatile organic compound(s), i.e., a secondary biogenic emission. Here, by studying the stable carbon isotope composition of formic and acetic acid in couple in the troposphere and relevant sources, we find the gap relates to primary biogenic emission and atmospheric lifetime of the acids. We show the primary biogenic emission is only second to the secondary biogenic emission as a strong source. Marine emission is the least one yet present in all the tropospheric environments except some local air. Long-distance transport of this origin indicates the lifetime over 5 days for both acids. Our results indicate that recent simulations underrated both primary biogenic emission and the lifetime. These underestimations would inevitably bias low the modeled results, especially in the low and free troposphere where primary biogenic emission and lifetime has the most pronounced influence, respectively. [ABSTRACT FROM AUTHOR] more...

Changes in the marine productivity and sedimentary environment since the last deglaciation in the Ross Sea are presented in this paper. Opal has replaced calcium carbonate as the major biogenic component and has a significantly positive correlation with total organic carbon (TOC), which indicates that siliceous phytoplankton controlled the absorption and release of carbon by the biological pump and was the main producer of marine organic matter. Using the AMS 14C age framework, foraminiferal fossils and redox sensitive elements (RSEs), we found that both the sedimentary environment and marine productivity changed clearly in ∼11 cal ka BP, which is more likely related with the melting and retreat of the Ross Ice Shelf. In addition, the increase of marine productivity promoted the sinking of more organic-matter to the seabed. A large proportion of oxygen in the bottom water body was consumed and more carbon dioxide was produced during the decomposition of organic matter, making the bottom water body more soluble to calcium carbonate. [ABSTRACT FROM AUTHOR] more...

Biogenic volatile organic compounds (bVOCs) play important roles in ecological interactions and Earth system processes, yet the biological and physical processes that drive soil bVOC exchanges remain poorly understood. In temperate forests, nearly all tree species associate with arbuscular mycorrhizal (AM) or ectomycorrhizal (ECM) fungi. Given well‐established differences in soil biogeochemistry between AM‐dominated and ECM‐dominated stands, we hypothesized that bVOC exchanges with the atmosphere would differ between soils from the two stand types. We measured bVOC fluxes at the soil‐atmosphere interface in plots dominated by AM‐ and ECM‐associated trees in a deciduous forest in south‐central Indiana, USA during the early and late vegetative growing season. Soils in both AM‐ and ECM‐dominated plots were a net bVOC sink following leaf‐out and were a greater bVOC sink or smaller source at warmer soil temperatures (Ts). The flux of different bVOCs from ECM plots was often related to soil water content in addition to Ts. Methanol dominated total bVOC fluxes, and ECM soils demonstrated greater uptake relative to AM‐dominated plots, on the order of 170 nmol m−2 hr−1 during the early growing season. Our results demonstrate the importance of soil dynamics characterized by mycorrhizal associations to bVOC dynamics in forested ecosystems and emphasize the need to study bidirectional soil bVOC uptake and emission processes. Plain Language Summary: Plants and soils emit and absorb complex carbon‐containing molecules in ways that remain poorly understood. These molecules—called "biogenic volatile organic compounds," or bVOCs—mediate ecological interactions, including plant defense, and also impact atmospheric chemistry, including aerosol formation. We are becoming more aware of the importance of "mycorrhizal associations" as indicators of biogeochemical variation in forests. Tree species that associate with arbuscular mycorrhizal fungi typically have fast‐decaying leaf litters and faster nutrient cycling relative to tree species that associate with ectomycorrhizal (ECM) fungi, which generally have slow‐decaying leaf litters and slower nutrient cycling. As such, we hypothesized that forest plots dominated arbuscular mycorrhizal‐ versus ECM‐associated trees would differ in their bVOC emissions. We measured soil bVOC flux in a deciduous forest in Indiana, USA, and noted that soils that were dominated by ECM fungi had greater bVOC uptake, especially when soils were warmer. bVOC uptake in soils dominated by ECM fungi was also sensitive to soil moisture. With this new knowledge, we can create improved models of bVOC fluxes at the ecosystem scale to gain a richer understanding of how soil characteristics impact ecosystem processes and atmospheric chemistry. Key Points: Deciduous hardwood forest soil was a net sink of biogenic volatile organic compounds (bVOCs) during the growing seasonWarmer soils increased the bVOC sink within arbuscular mycorrhizal‐dominated plotsbVOC flux in ectomycorrhizal‐dominated plots were sensitive to both soil temperature and moisture [ABSTRACT FROM AUTHOR] more...

Accurate and fine‐scale estimates of biogenic carbon fluxes are critical for measuring and monitoring the biosphere's responses and feedback to the climate system. Currently available data products from flux towers and model‐intercomparison projects struggle to adequately represent spatiotemporal dynamics of surface biogenic carbon fluxes, and to quantify their uncertainties, which also are crucial to atmospheric inversion systems. To address these gaps, we introduce a new perturbed‐parameter model ensemble with the CASA model to estimate surface biogenic carbon fluxes at monthly and 3‐hourly scales for North America at ~500‐m and 5‐km resolutions. We first use the Extended Fourier Amplitude Sensitivity Testing to choose the three most sensitive parameters to be perturbed, maximum light use efficiency (Emax), optimal temperature of photosynthesis (Topt), and temperature response of respiration (Q10). The initial range for each parameter is broadly sampled for the L1 ensemble, but then we pruned Emax with site‐level primary productivity to derive an L2 ensemble with narrower uncertainty ranges. Ensembles are strongly correlated with site‐level results at both monthly and 3‐hourly scales, and the spread across L1/L2 ensemble members encompasses the range of AmeriFlux observations. Monthly variability in the L2 ensemble mean is 85% of the observed variability. The L2 ensemble outperforms diverse data products with the highest Taylor skill scores at diurnal to annual scales. The ensemble's seasonality agrees well with other models for most biome types and in high and middle latitudes, but inconsistencies are found in subtropical and tropical ecoregions and for annual totals over North America. Key Points: By perturbing three key model parameters, the mean of the new ensemble outperforms other model products in comparison to flux tower dataSeasonal net carbon exchange shows consistency with other model products in high‐ and middle‐latitude regions and at continental scalesCold‐season respiration needs to be suppressed and maximum light use efficiency needs to be varied seasonally [ABSTRACT FROM AUTHOR] more...

We studied the ultrasculpture of pollen grains and the surface, the macro- and microstructure of the seeds of broad beans (Faba bean L.), peas (Pisum sativum L.) and common beans (Phaseolus vulgaris L.). It was revealed that pollen grains are single, medium in size, radially symmetric, threeaperture, but the exine surface sculpture and ornamentation of the pollen grain surface are of decisive importance. The main role in determining pollen grains is played by shape and ornamentation. It was also determined that the seeds of beans differ in the maximum sperm thickness, and the thickness of the sclerotest makes the main contribution to the formation of this trait. The bean epidermis of the seed peel is two-row and has the greatest thickness. When seeds germinate, the matrix protein and aleuron grains of the storage parenchyma are first consumed. Its cells and the size of starch grains are larger in broad beans. And the sign "the ratio of the size of starch grains to the size of the cells of the storage parenchyma,%" allows you to identify fragments of the seeds of broad beans, peas and beans without seed peels. [ABSTRACT FROM AUTHOR] more...

Research findings are made of reagent treatment processes of highly concentrated liquid wastes at pig farms in agro-industrial clusters (AIC) for the purpose of obtaining organo-mineral fertilizer and water for irrigation and increasing the fertility of agricultural lands. The research objective was to study the process of reagent fractionation of highly concentrated by nutrient elements liquid wastes of pig farms, with the replacement of the existing superphosphate reagent by more effective nitrogen and phosphorus. The main processes of liquid waste separation into fractions, determination of optimal reagent doses, comparison of results of different reagents use and recommendations are studied. Optimal portioning of ammophos suspension for treatment of highly concentrated waste was established and determined by the effect of separation into fractions. Researches were carried out at Platov South-Russian State Polytechnic University (NPI) in Novocherkassk. The usage of ammophos for fractionation of highly concentrated liquid waste of livestock farms, is to use as an acidifying reagent ammophos suspension, reducing the retention time in wet pits, as well as reducing reagent doses by more than 2 times, compared with superphosphate. The efficiency of waste separation was provided with the usage of ammophos and superphosphate was compared, optimal doses of ammophos suspension -0.5-1.5 g/dm³. The dependence of the separation efficiency of liquid waste as a function of its temperature was studied, the kinetics of separation at increasing temperature increases in the range from 20-45 °C. The greatest effect of separation of liquid waste was observed at a temperature of 45°C, but the separation efficiency, ranging from 20 to 45 0C varies slightly. Nevertheless, it was accepted that the optimal temperature for reagent processing of highly concentrated liquid waste from pig farms of agro-industrial clusters was 20-25 °C. [ABSTRACT FROM AUTHOR] more...

The study is focused on microbiological analyses in polar soils in selected monitoring sites in Livingstone Island, Antarctica region. The analyses include determination of the quantity and qualitative composition of the heterotrophic block of soil microflora (non-spore-forming bacteria, bacilli, actinomycetes, micromycetes, bacteria absorbing mineral nitrogen), insofar as it plays a major role in the element cycling and soil formation processes. Aerobic (rapidly and slowly growing) and anaerobic groups of soil microorganisms were investigated and the biogenicity (total microflora) and the rate of mineralisation processes (mineralisation coefficient) were determined. Mostly non-spore-forming aerobic bacteria, followed by actinomycetes, are dominant in determining the biogenicity of the studied polar soils. The rearrangement of the microorganisms in the composition of the total microflora by degree of dominance indicates the participation of all the studied groups of microorganisms in most sites in the initial and final stages of the decomposition of organic matter. The mineralisation of soils is most active in sites with vegetation cover. The established pigmentation in aerobic microorganisms is probably due to their good adaptation and protection under extreme polar conditions, while the absence of oxygen impedes the formation of pigments. [ABSTRACT FROM AUTHOR] more...

Regional estimates of biogenic carbon fluxes over North America from both atmospheric inversions ("top‐down" approach) and terrestrial biosphere models ("bottom‐up") remain highly uncertain. We merge these approaches with an ensemble‐based, regional modeling system able to diagnose and quantify the causes of uncertainties in top‐down atmospheric estimates of the terrestrial sink over North America. Our ensemble approach quantifies and partitions the uncertainty stemming from atmospheric transport, the biosphere, and large‐scale CO2 boundary inflow (boundary conditions). We use meteorological data, CO2 fluxes, and CO2 mole fraction measurements to assure the reliability of the ensemble system. Our results show that all uncertainty components have clear seasonal variations. The biogenic flux component dominates modeled boundary layer CO2 uncertainty, ranging from 2.5 ppm in summer and winter to 1.5 ppm in fall and spring. Spatially, it remains highly uncertain in the U.S. Corn Belt regions. Transport uncertainty reaches a maximum of 2.5 ppm in the summer months and stays at 1.2 ppm for the rest of the year and is highly correlated with the biogenic CO2 fluxes. Boundary conditions play the smallest role in atmospheric boundary layer CO2 uncertainty with a magnitude smaller than 1 ppm. However, boundary conditions are the most important uncertainty component in column‐averaged CO2 (XCO2). The spatiotemporal variations of the uncertainties in modeled XCO2 are similar to those in atmospheric boundary layer CO2. Plain Language Summary: Uncertainty in future uptake of carbon dioxide (CO2) by terrestrial ecosystems drives divergent projections of future climate and uncertainty in prescriptions for climate mitigation. North American ecosystems are currently a significant sink of atmospheric CO2, but this sink is difficult to measure and thus understand. Terrestrial uptake and emission of CO2 from a continent such as North America can be inferred from atmospheric CO2 observations. This approach, however, requires an accurate understanding of all the sources of uncertainty in simulating atmospheric CO2. These include errors in the simulations of atmospheric transport, fossil fuel emissions of CO2, and transport of CO2 from the rest of the Earth's continents and oceans (boundary conditions), in addition to the uncertainty terrestrial CO2 uptake. Here we quantify the uncertainty in all of these components of an atmospheric CO2 simulation over North America using an ensemble of simulations. Observations of atmospheric winds and mixing, atmospheric CO2 mole fractions, and land‐atmosphere CO2 fluxes are used to ensure that the ensemble cover an appropriate range of uncertainty in each element of our simulation. Our results show that over North America, (i) terrestrial biosphere CO2 fluxes dominate the uncertainty in the atmospheric boundary layer CO2, (ii) atmospheric transport uncertainty is highly correlated with biosphere flux uncertainty in space and time, and (iii) inflow of CO2 from other continents and oceans plays the least important role in North American lower atmosphere CO2 but is the largest source of uncertainty in atmospheric column‐integrated CO2. Our study shows that atmospheric transport and continental boundary conditions are important limits to our ability to infer terrestrial ecosystem CO2 uptake using, respectively lower atmosphere and atmospheric column CO2 measurements. Key Points: Our calibrated ensemble system demonstrates that biogenic fluxes dominate the uncertainty in atmospheric boundary layer CO2Transport uncertainty is highly correlated with biogenic flux uncertainty in space and timeLarge‐scale CO2 boundary inflow dominates uncertainty in the atmospheric column‐integrated CO2 uncertainty [ABSTRACT FROM AUTHOR] more...

The climate and environmental significance of the Deccan Traps large igneous province of west-central India has been the subject of debate in paleontological communities. Nearly one million years of semi-continuous Deccan eruptive activity spanned the Cretaceous-Paleogene boundary, which is renowned for the extinction of most dinosaur groups. Whereas the Chicxulub impactor is acknowledged as the principal cause of these extinctions, the Deccan Traps eruptions are believed to have contributed to extinction patterns and/or enhanced ecological pressures on biota during this interval of geologic time. We present the first coupled records of biogenic carbonate clumped isotope paleothermometry and mercury concentrations as measured from a broad geographic distribution of marine mollusk fossils. These fossils preserve evidence of simultaneous increases in coastal marine temperatures and mercury concentrations at a global scale, which appear attributable to volcanic CO2 and mercury emissions. These early findings warrant further investigation with additional records of combined Late Cretaceous temperatures and mercury concentrations of biogenic carbonate. The relative role of the Deccan Traps volcanic activity versus the role of the Chicxulub impact event in terms of potential contributions to the Cretaceous-Paleogene (K-Pg) mass extinction has been subject to longstanding debate. Here, the authors observe a global signal of abruptly increased ocean temperatures and elevated [Hg] in the same biogenic carbonate specimens, prior to the impact event but aligning with the onset of Deccan volcanism. [ABSTRACT FROM AUTHOR] more...

Inland waters, including streams and rivers, are active components of the global carbon cycle. Despite the large areal extent of the world's mountains, the role of mountain streams for global carbon fluxes remains elusive. Using recent insights from gas exchange in turbulent streams, we found that areal CO2 evasion fluxes from mountain streams equal or exceed those reported from tropical and boreal streams, typically regarded as hotspots of aquatic carbon fluxes. At the regional scale of the Swiss Alps, we present evidence that emitted CO2 derives from lithogenic and biogenic sources within the catchment and delivered by the groundwater to the streams. At a global scale, we estimate the CO2 evasion from mountain streams to 167 ± 1.5 Tg C yr−1, which is high given their relatively low areal contribution to the global stream and river networks. Our findings shed new light on mountain streams for global carbon fluxes. Freshwater systems are important components of the carbon cycle, but the extent of their role in CO2 fluxes is poorly understood. Here Horgby and colleagues show that mountain streams are a surprisingly large source of CO2 to the atmosphere, with annual emissions that belie their spatial extent. [ABSTRACT FROM AUTHOR] more...

Geological evidence shows that life on Earth evolved in line with major concomitant changes in Earth surface processes and landforms. Biogeomorphological characteristics, especially those involving microorganisms, are potentially important facets of biosignatures on Mars and are generating increasing interest in astrobiology. Using Earth as an analog provides reasons to suspect that past or present life on Mars could have resulted in recognizable biogenic landforms. Here, we discuss the potential for, and limitations of, a biogeomorphological approach to identifying the subsets of landforms that are modulated or created through biological processes and thus present signatures of life on Mars. Subsets especially involving microorganisms that are potentially important facets of biosignatures on Mars are proposed: (i) weathering features, biocrusts, patinas, and varnishes; (ii) microbialites and microbially induced sedimentary structures (MISS); (iii) bioaccumulations of skeletal remains; (iv) degassing landforms; (v) cryoconites; (vi) self-organized patterns; (vii) unclassified non-analog landforms. We propose a biogeomorphological frequency histogram approach to identify anomalies/modulations in landform properties. Such detection of anomalies/modulations will help track a biotic origin and lead to the development of an integrative multiproxy and multiscale approach combining morphological, structural, textural, and geochemical expertise. This perspective can help guide the choice of investigation sites for future missions and the types and scales of observations to be made by orbiters and rovers. [ABSTRACT FROM AUTHOR] more...

Biogenic volatile organic compounds (BVOCs) can be released from soils to the atmosphere through microbial decomposition of plant residues or soil organic carbon, root emission, evaporation of litter‐stored BVOCs, and other physical processes. Soils can also act as a sink of BVOCs through biotic and abiotic uptake. Currently, the source and sink capabilities of soils have not been explicitly accounted for in global BVOC estimates from the terrestrial biosphere. In this review, we summarize the current knowledge of soil BVOC processes and aim to propose a generic framework for modelling soil BVOCs based on current understanding and data availability. To achieve this target, we start by reviewing measured sources and sinks of soil BVOCs and summarize commonly reported compounds. Next, we strive to disentangle the drivers for the underlying biotic and abiotic processes. We have ranked the list of compounds, known to be emitted from soils, based on our current understanding of how each process controls emission and uptake. We then present a modelling framework to describe soil BVOC emissions. The proposed framework is an important step toward initializing modelling exercises related to soil BVOC fluxes. Finally, we also provide suggestions for measurements needed to separate individual processes, as well as explore long‐term and large‐scale patterns in soil BVOC fluxes. Plain Language Summary: Living plants emit biogenic volatile organic compounds (BVOCs), which have impacts on regional and global climate. However, BVOCs can also be released from fallen leaf litter, plant roots, and soil organic matter, and some compounds are also consumed by soil microbes. In this article, we begin by sorting out the processes that govern soil emissions and uptakes of BVOCs and summarize the current understanding and available data for each process. Furthermore, we propose a generic modelling framework to add soil BVOC‐related processes into the typical structure existing in many ecosystem models. We also provide suggestions for future measurements that would help with model‐data integration. Key Points: We present biotic and abiotic drivers for soil BVOC emissions and sinksWe summarize the often‐reported compounds and key processes regulating their fluxesWe propose a generic framework for including soil BVOCs in ecosystem models [ABSTRACT FROM AUTHOR] more...

The complex surface topography of river substrates controls near‐bed hydraulics and drives the exchange of subsurface and surface flow. In rivers, the topographic structures that are studied are usually formed by the flow, but it is known that many animals also create biogenic bedforms, such as pits and mounds. Here, a large‐eddy simulation model of flow over a pit and a mound is evaluated with flume experiments. The model includes actual bedform topography, and the topographic complexity of the surrounding bed surface. Subsurface grains are organized in a body‐centered cubic packing arrangement. Model evaluation showed strong agreement between experimental and modeling results for velocity (R2 > 0.8) and good agreement for Reynolds stresses (R2 > 0.7), which is comparable to other similar studies. Simulation of the pit shows that the length of the downwelling region is smaller than the upwelling region and that the velocity magnitude is higher in the downwelling region. Simulation of the mound reveals that the flow is forced into the bed upstream of the mound and reemerges near the top of the mound. The recirculation zone is limited at the leeside of the mound. With increasing Reynolds number, the depth of the upwelling region at the leeside of the mound increases. The analysis of shear stress indicates that sediments on the upstream edge of the pit and on the downstream face of the mound are relatively unstable. These results demonstrate the effect of biogenic structures on the near‐bed flow field, hyporheic exchange, and sediment stability. Key Points: A novel, unified water‐sediment three‐dimensional model is developed to investigate the impact of simulated biogenic bedformsThe impact of biogenic bedforms on near‐bed turbulence and sediment entrainment is discussed in gravelly substratesBiogenic bedform morphology has an important role in determining the spatial extent of up‐ and down‐welling flow [ABSTRACT FROM AUTHOR] more...

Sedimentation of particles in the ocean leads to inhomogeneous horizontal distributions at depth, even if the release process is homogeneous. We study this phenomenon considering a horizontal sheet of sinking particles immersed in an oceanic flow and determine how the particles are distributed when they sediment on the seabed (or are collected at a given depth). The study is performed from a Lagrangian viewpoint attending to the properties of the oceanic flow and the physical characteristics (size and density) of typical biogenic sinking particles. Two main processes determine the distribution, the stretching of the sheet caused by the flow, and its projection on the surface where particles accumulate. These mechanisms are checked, besides an analysis of their relative importance to produce inhomogeneities, with numerical experiments in the Benguela region. Faster (heavier or larger) sinking particles distribute more homogeneously than slower ones. Key Points: Biogenic particles homogeneously released from the upper ocean sediment showing an inhomogeneous horizontal distributionThe mechanism is a combination of the stretching of the sheet of particles due to the flow, and the final projection on the seabedLighter particles develop stronger inhomogeneities compared to heavier ones, as shown in the particular case of the Benguela region [ABSTRACT FROM AUTHOR] more...

Submarine groundwater discharge (SGD) is a significant source of biogenic elements in estuaries, and relevant studies in karstic estuaries are scarce. Krka River Estuary (KRE), located on the eastern Adriatic Sea (Croatia), is a typical oligotrophic stratified karstic estuary. In this study, based on 226Ra and 228Ra, the total SGD flux into the KRE surface layer was estimated to be (12.8–16.2) × 105 m3/day. A conservative estimation of the fresh groundwater flux was (5.0–8.3) × 105 m3/day, which accounts for 10–17% of the Krka River discharge into the estuary. By establishing water and nutrient budgets in the KRE surface layer, we found that SGD dominated the nutrient sources, although it accounted for a small portion of the total inflow water. Specifically, net SGD‐derived dissolved inorganic nitrogen (DIN) and silicates contributed 58–90% and 24–64%, respectively, to the total input fluxes. These results indicate that SGD was a major external nutrient source, in which net SGD‐derived high DIN flux and high DIN to dissolved inorganic phosphorus ratio may affect productivity in the KRE ecosystem and nearby Adriatic Sea. Additionally, net SGD‐derived dissolved inorganic carbon (DIC) flux in the KRE (1.53 mol · m2 · day) was much higher than those in most estuaries worldwide, suggesting that the DIC‐enriched karst aquifers are important sources for global carbon cycle. Therefore, the impact of net SGD‐derived DIC from karst aquifers on coastal seas will likely become more evident and substantial with further development of global climate change, such as sea level rise. Plain Language Summary: Coastal karst aquifers are very vulnerable and sensitive to climate and environmental changes. In this study, we evaluated the impacts of submarine groundwater discharge in a typical oligotrophic highly stratified karstic estuary. Using multiple parameters and mathematical models, we found that the net SGD‐derived nutrient flux could affect the productivity of this coastal ecosystem, notably contributing to forming the conditions that lead to the occurrence of phytoplankton blooms. In addition, nutrient‐enriched SGDs from the karst aquifers are likely to be important but easily ignored sources for the global carbon cycle. Taken together, our study revealed the impacts of submarine groundwater from the karst aquifers on the coastal seas, which shall become increasingly evident and substantial with further development of global climate change, such as the rise of sea level. Key Points: 226Ra and 228Ra were used to estimate SGD in an oligotrophic stratified karstic estuaryNet SGD‐derived nutrients have potential to impact the ecosystem in the Krka River Estuary by high DIN flux and DIN:DIP ratioSGD from DIC‐enriched coastal karst aquifers make a significant contribution to the carbon cycle of the coastal seas worldwide [ABSTRACT FROM AUTHOR] more...

Abstract Kettle holes are a circular-shape product of ice decay, and thus are strongly linked with young glacial landscapes. Once glaciation terminates, these holes transform either into wetland and lakes or occasionally into kettle-hole mires. Since an entire sediment sequence preserve in the kettle-holes, these provide an excellent settings to exploit any sensitive paleoenvironmental changes. Here, the kettle-hole mire located onto the Brda River outwash plain (Tuchola Forest) is explored towards a better understanding of local and global environmental trends in the Late Glacial – present day time frame. To fulfill this, multi-proxy study as geochemical, palynological and macrofossils analyses along with the radiocarbon dating are used. Therefore, this study allows to distinguish five phases of steep environmental gradients in the investigated mire, as follows: (1) paludification after glaciation, when dead-ice melted and long-term permafrost was degraded, (2) lake started to disappear in the Late Glacial, followed by a rich vegetation in the first part of the Holocene, (3) vegetation encroachment onto the lake in the first part of the Holocene, which consequently turned into an peat bog, (4) the late Holocene peat bog with a limited human influence, and finally (5) the peat bog with a major human impact along with acidification as related to sandy underlying sediments, leaching of calcium carbonate, recharge from precipitation and pine monoculture. As additionally apparent from this small ecosystem, both local (character of substrate sediments, morphology of the area, rate of permafrost melting, climate conditions and human activity) and regional (climate changes and human activity) are detectable. Nevertheless, the record of these changes is sometimes unclear. Highlights • Multi-proxy study of biogenic kettle-hole sediment in North Central Poland. • Kettle-hole developed in five phases in the Late Glacial – the Holocene time frame. • Record of vegetational and chemical changes in the kettle-hole sediments • Intensive erosion along with acidification took place. • A greater human impact at the end of the Atlantic [ABSTRACT FROM AUTHOR] more...

The historical development of ice nucleating particle concentrations (NINP) is still unknown. Here, we present for the first time NINP from the past 500 years at two Arctic sites derived from ice core samples. The samples originate from the EUROCORE ice core (Summit, Central Greenland) and from the Lomo09 ice core (Lomonosovfonna, Svalbard). No long‐term trend is obvious in the measured samples, and the overall range of NINP is comparable to present‐day observations. We observe that the short‐term variations in NINP is larger than the long‐term variability, but neither anthropogenic pollution nor volcanic eruptions seem to have influenced NINP in the measured temperature range. Shape and onset temperature of several INP spectra suggest that INP of biogenic origin contributed to the Arctic INP population throughout the past. Key Points: No obvious trend of Arctic INP concentrations over the past 500 years is observedShort‐term variability in INP concentrations is larger than long‐term variationA contribution of biological sources to the Arctic INP population is likely [ABSTRACT FROM AUTHOR] more...

Abstract Like microbialites, microbially induced sedimentary structures (MISSs) are commonly observed in siliciclastic and mixed carbonate siliciclastic settings in the Lower Triassic, and are represented by several morphological types including wrinkle structures. However, their origin and their role in the Early Triassic ecosystem recovery is currently a hot topic of debate. Herein we report and describe abundant wrinkle structures from the Smithian Kockatea Shale Formation of Northampton area in the Perth Basin, Western Australia, on the basis of detailed field observations as well as petrographic and SEM examinations of rock thin sections. The surficial morphologies of wrinkles are characterized by closely spaced crests and ridges on the upper bedding surfaces, together with other forms such as pitted bulges and reticulated ridges. Detailed petrologic analysis revealed that the Smithian wrinkle structures from the northern Perth Basin possess a distinct vertical profile: (1) cross-stratified/lamianted sandstone, (2) alternating laminated layers and sandstone, (3) laminated layers, and (4) wrinkled layers, in an ascending order. The wrinkled layers are overlain by thin shale. Laminated layers beneath wrinkled surfaces comprise densely packed, pronounced, wavy laminae. Mica flakes in laminations show a preferred alignment parallel to bedding under SEM imaging, suggesting the binding and trapping of the former presence of a microbial matground. These evidences support that the Early Triassic wrinkle structures from the Smithian Kockatea Formation are biogenic in origin. Close association of both trace and body fossils with the wrinkle structure-bearing layers is interpreted to indicate the presence of a matground ecosystem in which some small gastropods and various trace-making animals lived, possibly taking the habitat as a refuge. The global temporal and spatial occurrences of Early Triassic MISS were tabulated and analyzed, revealing a wide range of palaeoenvironmental distributions and the seemingly selected association between metazoans and certain MISS. As to why only some MISSs have been found together with metazoans remains as an open question. It will require further investigation especially with regard to the specific type of microbes that had built the microbial matground ecosystems and their interplay with the hosted metazoans in the aftermath of the end-Permian mass extinction. Highlights • Lower Triassic wrinkle structures from the Kockatea Formation were documented. • Various evidence support the biogenic origin of wrinkle structures • Possible matground habitat suggested by co-occurrence of fossils with wrinkle structures • Complicated environmental factors responsible for matground ecosystem development in Early Triassic [ABSTRACT FROM AUTHOR] more...

Abstract We report small microbialites from the calcareous mudstone slightly above the Permian–Triassic boundary (PTB) in the Tieshikou section, southern Jiangxi Province, South China. The newly found microbialite is a bowl-like structure, which contrasts with the surrounding calcareous mudstone. The small microbialite is composed of columnar forms and fan-shaped structures. Mini-columnar structures resemble mini stromatolites. In plane view, most branches are patchy or strip-shaped, with clotted structures, resembling that of a thrombolite. Fan-shaped cement precipitates are comprised of multiple crystal fans that have a radiating texture and that show distinct growth laminae. The radiating fabrics are represented by rod-shaped filaments under SEM, which are interpreted as calcified trichomes/filaments. Prominent micropores occur within the rods, and they may be the plane views of multiple sheaths of the false branching zone of trichomes. Thus, both the columnar forms and radiating fans are probably microbial in origin. Moreover, three types of nano-sized structures: intraparticle micropores, fibrous biofilms, and filamentous sheaths are also pronounced in both the columnar structures and cement fans of the Tieshikou microbialite, all suggestive of biogenicity. These well-preserved fibrous biofilms probably represent calcified extracellular polymeric substances (EPS), and linear sheaths are interpreted as the traces of bacterial activities during the precipitation of dolomite crystals. The Tieshikou microbialite therefore shares similar biogenetic mechanisms with other PTB microbialites. The combination of the absence of pyrite framboids, slightly negative carbon isotope values, and an association with abundant ammonoids, bivalves, and gastropods indicates oxic conditions during the growth of the Tieshikou microbialite. Moreover, the nodular preservational state resembles widely distributed nodular mudstones or muddy limestones of the Lower Triassic successions worldwide. This implies that nodular mudstone or argillaceous limestones may also have been deposited in microbe-rich environments, in which terrigenous supply was abundant. Highlights • Small microbialites from mudstone near Permian–Triassic boundary • Laminated columnar structures and fibrous cement fans • Rod-shaped objects with micropores represent false branching zone of trichomes. • Four types of nano-sized structures suggestive of biosignatures • Microbial proliferation in limestone nodules in the post-extinction siliciclastic setting [ABSTRACT FROM AUTHOR] more...

Abstract The aim of this work was to study concurrent removal of nitrate, arsenic and iron in an attached growth reactor (AGR) based on bio-sulphidogenesis treating simulated and real-life ground water. A lab-scale bioreactor system was monitored for a period of 511 days under conditions identical to those prevailing at full-scale to assess the relative influence of empty bed contact time (EBCT) (20–90 min), backwash strategies (water-nitrogen and water-air), temperature (20–50 °C), pH (6.6–8.4) and shut down on reactor performance and recovery. Complete removal of nitrate (50 mg/L) and over 95% removal of iron (3 mg/L) occurred. Arsenic removal efficiency was around 99% (500 μg/L) and treated water arsenic concentration was in compliance with the World Health Organization and Indian Standard of 10 μg/L. Port sampling along the depth of bioreactor shows shifting of terminal electron accepting process zones at lower EBCT of 20 min and after air assisted backwashing. The temperature range of 20–50 °C and pH range of 6.6–8.4 were applicable for arsenic removal in natural conditions. Precipitated biosolids were analysed using electron microscopy. Biogenic sulphides resulted in the precipitation of arsenosulphides and iron sulphides, which concurrently removed arsenic and iron. This study suggests that a sulphidogenic bioreactor may help to set the basis for concurrent removal of nitrate, arsenic and iron from real-life groundwater using mixed biofilm bacterial community. Graphical abstract Image 1 Highlights • Concurrent N O 3 − , Fe and As removal from simulated and real-life groundwater. • 500 μg/L As was reduced to below 10 ppb along with 50 mg/L N O 3 − and 3 mg/L Fe. • N O 3 − , As and Fe in treated water meet drinking water WHO and Indian standards. • Efficient As removal was seen at varying temperature (20–50 °C) and pH (6.6–8.4). • Precipitation of biogenic iron pyrite crystals are observed as main iron sulphides. [ABSTRACT FROM AUTHOR] more...

Abstract In the next decades, a large share of residential buildings in EU-28 is expected to be renovated to achieve the 2 °C target requested by the Paris Agreement by 2050. Bio-based materials used for increasing the thermal insulation and temporary store carbon in construction elements might be a valuable opportunity that can contribute to accelerate the transition to a zero-carbon society. This article investigates the effect of massively storing carbon in bio-based construction products when used for the renovation of existing facades. Five alternative construction solutions were compared, three with a large amount of fast-growing biogenic material used as insulation, one with timber used for the frame and additional fibrewood as insulation, and the last one with synthetic insulation. A statistic-based Geocluster model was developed to predict the future material flow for building renovation in EU-28 and a dynamic life cycle assessment performed in order to verify the contribution of construction materials in reducing/increasing the carbon emissions over time. The results show that fast-growing biogenic materials have an increased potential to act as a carbon sink compared to timber. In particular, if straw is used as an insulation material, the capacity to store carbon from the atmosphere is effective in the short-term, which represents an important strategy towards the Paris climate Agreement goals. Highlights • Large amounts of insulation will be required for building retrofit in the EU-28. • Slow carbon uptake of forests hinders reaching carbon neutrality by 2050. • Short-rotation biomass is the most effective means of carbon storage. [ABSTRACT FROM AUTHOR] more...

Abstract The legal commercialization of Cannabis for recreational and medical use in certain US states has effectively created a new and nearly unregulated cultivation industry. Within the city limits of Denver, Colorado, there are now more than 600 registered Cannabis spp. cultivation facilities (CCFs) for recreational and medical uses, each containing thousands of plants. Ambient measurements collected inside growing operations pre-legalization have found concentrations as high as 50–100 ppbv of terpenes; a group of highly reactive biogenic volatile organic compounds (BVOCs) and known precursors for the formation of ozone and particulate matter (PM). Due to its illicit nature there has been insufficient experimental data produced to determine Cannabis spp. emission rates. This study used, for the first time, an enclosure chamber and live Cannabis spp. plants during a 90-day growing period consisting of four different strains of Cannabis spp. : Critical Mass, Lemon Wheel, Elephant Purple, and Rockstar Kush. These measurements enabled characterization of terpenes and estimates of emission capacity (EC, μgC g−1 hr−1) at standard conditions. During peak growth, the percentages of individual BVOC emissions were dominated by β-myrcene (18–60%), eucalyptol (17–38%), and d-limonene (3–10%) for all strains. Our results showed large variability in the rate and composition of terpene emissions across different strains. For the Critical Mass and Lemon Wheel, the dominant terpenoid was eucalyptol (32% and 38%), and it was β-myrcene (60% and 45%) for the Elephant Purple and Rockstar Kush. Critical Mass produced the highest terpene emission capacity (8.7 μgC g−1 hr−1) and Rockstar Kush the lowest (4.9 μgC g−1 hr−1). With 600 CCFs in Denver, and assuming 10,000 plants per CCF, an emission capacity of 8.7 μgC g−1 hr−1 would more than double the existing rate of BVOC emissions to 520 metric ton year−1. Using Maximum Incremental Reactivity (MIR) values the total ozone formation potential from all these emitted species could produce 2100 metric tons year−1 of ozone, and based on published secondary organic aerosols yields 131 metric tons year−1 of PM. It is likely that the ECs calculated here are lower than those achieved in CCFs where growing conditions are optimized for rapid growth and higher biomass yields. Further studies including a greater number of the 620 available Cannabis spp. strains and a wider range of treatments are needed to generate a representative dataset. Such a dataset could then better enable assessments of the potential impacts of this new industry on indoor and regional air quality. Highlights • This study presents the first leaf enclosure measurements of terpene emission rates from four commercial Cannabis spp. strains. • Emission terpene composition varied among the four strains and at different growth stages. • The result offers a good first step of demonstrating the potential impacts of emission from this new industry. [ABSTRACT FROM AUTHOR] more...

The article discusses that hydrogels from biological sources are used as structural biomaterials but are soft or fragile. The research states that strategy is used to construct hydrogels that were both stiff and tough using the formation of the conjoined-network, that was different from improving homogeneity or incorporating energy dissipation mechanisms (double-network) approaches. more...

Abstract The continuous increase in water pollution by various organic & inorganic contaminants has become a major issue of concern worldwide. Furthermore, the anthropogenic activities for the manufacturing of various products have boosted this problem manifold. To overcome this serious issue, nanotechnology has initiated to explore various proficient strategies to treat waste water in a more precise and accurate way with the support of various nanomaterials. In recent times, nanosized materials have proved their applicability to provide clean and affordable water treatment technologies. The exclusive features such as high surface area and mechanical properties, greater chemical reactivity, lower cost and energy, efficient regeneration for reuse allow the nanomaterials perfect for water remediation. But the conventional routes of synthesis of nanomaterials encompass the involvement of hazardous and volatile chemicals; therefore the use of nanomaterials further creates the secondary pollution. This issue has intrigued the scientists to develop biogenic pathways and procedures which are environmentally safer and inexpensive. It has led to the new trends that involve developing bio-inspired nano-scale adsorbents and catalysts for the removal and degradation of a wide range of water pollutants. Carbohydrates, proteins, polymers, flavonoids, alkaloids and several antioxidants obtained from plants, bacteria, fungi, and algae have proven their effectiveness as capping and stabilizing agents during manufacture of nanomaterials. Application of biogenic nanomaterials for waste water treatment is relatively newer but rapidly escalating area of research. In the present review, promises and challenges for the synthesis of various biogenic nanomaterials and their potential applications in waste water treatment and/or water purification have been discussed. Highlights • Applications of biogenic nanoparticles for water treatment have been highlighted. • Roles of biomolecules in nanoparticles synthesis have been discussed. • The mechanism of removal has been explained in brief. • All sorts of water pollutants have been targeted. [ABSTRACT FROM AUTHOR] more...

In an incompressible flow, fluid density remains invariant along fluid element trajectories. This implies that the spatial distribution of non-interacting noninertial particles in such flows cannot develop density inhomogeneities beyond those that are already introduced in the initial condition. However, in certain practical situations, density is measured or accumulated on (hyper-) surfaces of dimensionality lower than the full dimensionality of the flow in which the particles move. An example is the observation of particle distributions sedimented on the floor of the ocean. In such cases, even if the initial distribution of noninertial particles is uniform but its support is finite, advection in an incompressible flow will give rise to inhomogeneities in the observed density. In this paper, we analytically derive, in the framework of an initially homogeneous particle sheet sedimenting toward a bottom surface, the relationship between the geometry of the flow and the emerging distribution. From a physical point of view, we identify the two processes that generate inhomogeneities to be the stretching within the sheet and the projection of the deformed sheet onto the target surface. We point out that an extreme form of inhomogeneity, caustics, can develop for sheets. We exemplify our geometrical results with simulations of particle advection in a simple kinematic flow, study the dependence on various parameters involved, and illustrate that the basic mechanisms work similarly if the initial (homogeneous) distribution occupies a more general region of finite extension rather than a sheet. [ABSTRACT FROM AUTHOR] more...

The reworking of sandy sediments in shallow coastal and shelf seas is mainly driven by physical forcing in the form of wave- and current-induced shear stress. As an important habitat for benthic species seeking shelter and food, the upper seafloor is also marked by intense bioturbation. Although this reworking activity is recognized as an important mechanism for the exchange of particular matter and solutes between sediment and water column, quantifications and assessments of the relative importance of physical and biogenic reworking of subtidal shelf sediments are rare. This work presents in situ measurements of volumetric reworking rates from six different locations in the southeastern North Sea. The investigated sites cover a range of water depths between 23 and 41 m, different magnitudes of physical (wave and current) forcing and sedimentological conditions as well as different habitats and benthic communities. The measured biogenic reworking rates reach up to 14% of physically driven reworking via bedform migration. Comparisons with physical quantities water depth, median grain size, bottom water temperature and flow velocity reveal good correlations and allow for an approximation of the biogenic reworking rate from a combination of these readily available oceanographic parameters. The diffusive relocation of sediment by benthic fauna also influences the topography of small scale bedforms and may reduce their height by up to 10% in a few hours during hydrodynamically inactive conditions. The observations show that even in an energetic environment such as the southeastern North Sea, the benthic fauna contributes an important regulating ecosystem service by overturning upper seafloor sediments. This reworking mechanism becomes particularly important in areas and during periods of sub-threshold conditions for physically driven sediment reworking. [ABSTRACT FROM AUTHOR] more...

The assessment of diagenetic overprint on microstructural and geochemical data gained from fossil archives is of fundamental importance for understanding palaeoenvironments. The correct reconstruction of past environmental dynamics is only possible when pristine skeletons are unequivocally distinguished from altered skeletal elements. Our previous studies show (i) that replacement of biogenic carbonate by inorganic calcite occurs via an interface-coupled dissolution–reprecipitation mechanism. (ii) A comprehensive understanding of alteration of the biogenic skeleton is only given when structural changes are assessed on both, the micrometre as well as on the nanometre scale. In the present contribution we investigate experimental hydrothermal alteration of six different modern biogenic carbonate materials to (i) assess their potential for withstanding diagenetic overprint and to (ii) find characteristics for the preservation of their microstructure in the fossil record. Experiments were performed at 175 ∘C with a 100mMNaCl+10mMMgCl2 alteration solution and lasted for up to 35 days. For each type of microstructure we (i) examine the evolution of biogenic carbonate replacement by inorganic calcite, (ii) highlight different stages of inorganic carbonate formation, (iii) explore microstructural changes at different degrees of alteration, and (iv) perform a statistical evaluation of microstructural data to highlight changes in crystallite size between the pristine and the altered skeletons. We find that alteration from biogenic aragonite to inorganic calcite proceeds along pathways where the fluid enters the material. It is fastest in hard tissues with an existing primary porosity and a biopolymer fabric within the skeleton that consists of a network of fibrils. The slowest alteration kinetics occurs when biogenic nacreous aragonite is replaced by inorganic calcite, irrespective of the mode of assembly of nacre tablets. For all investigated biogenic carbonates we distinguish the following intermediate stages of alteration: (i) decomposition of biopolymers and the associated formation of secondary porosity, (ii) homoepitactic overgrowth with preservation of the original phase leading to amalgamation of neighbouring mineral units (i.e. recrystallization by grain growth eliminating grain boundaries), (iii) deletion of the original microstructure, however, at first, under retention of the original mineralogical phase, and (iv) replacement of both, the pristine microstructure and original phase with the newly formed abiogenic product. At the alteration front we find between newly formed calcite and reworked biogenic aragonite the formation of metastable Mg-rich carbonates with a calcite-type structure and compositions ranging from dolomitic to about 80 mol% magnesite. This high-Mg calcite seam shifts with the alteration front when the latter is displaced within the unaltered biogenic aragonite. For all investigated biocarbonate hard tissues we observe the destruction of the microstructure first, and, in a second step, the replacement of the original with the newly formed phase. [ABSTRACT FROM AUTHOR] more...

Abstract Sugars and n -alkanes are important organic constituents of atmospheric fine particulate matter (PM 2.5). For better understanding their sources and seasonal variations in urban atmosphere, sugar compounds (anhydrosugars, sugars and sugar alcohols) and homologue n- alkanes (C 18 –C 37) were studied in PM 2.5 samples collected from September 2013 to July 2014 in Beijing, China. In general, all measured compounds showed the lowest levels in summer. Higher concentrations of sugar compounds and n -alkanes were observed in winter, probably due to elevated combustion emissions (e.g., coal, biofuel and agricultural residue burning) and stable meteorological conditions during heating season. Levoglucosan was the major sugar species in all seasons particularly in autumn and winter, highlighting the significant contribution of biomass burning to fine organic aerosols throughout the whole year especially in cold seasons. Plant waxes contributed to n -alkanes the most in late spring (54.5%) and the least in winter (11.6%); while fossil fuel combustion had the largest contribution in winter (385 ng m−3). The weak odd-carbon predominance of n -alkanes in wintertime aerosols also suggests fossil fuel combustion as the important source of organic aerosols in the heating season. Soil resuspension, fossil fuel combustion and biomass burning, and secondary sources are the main sources of OC in PM 2.5 at Beijing. The seasonal variation in source contributions indicates that meteorological condition is a key factor in controlling PM 2.5 levels. Furthermore, dust storms in spring can strongly enhance the atmospheric level of fine organic matter in Beijing. Graphical abstract Image 1 Highlights • Biomass burning contributes significantly to PM 2.5 during the whole year, particularly in cold seasons. • n -Alkanes mainly originate from plant waxes in spring while from fossil fuel combustion in heating season. • Dust storms in spring account for high atmospheric levels of fine organic matter. Our study highlights the importance of biomass burning to PM 2.5 throughout the year especially in cold seasons, and dust storms notably enhance fine organic aerosols in spring. [ABSTRACT FROM AUTHOR] more...

The biogenic sulfur compounds dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO) are produced and transformed by diverse populations of marine microorganisms and have substantial physiological, ecological and biogeochemical importance spanning organism to global scales. Understanding the production and transformation dynamics of these compounds under shifting environmental conditions is important for predicting their roles in a changing ocean. Here, we report the physiological and biochemical response of Alexandrium minutum, a dinoflagellate with the highest reported intracellular DMSP content, exposed to a 6 day increase in temperature mimicking coastal marine heatwave conditions (+4°C and +12°C). Under mild temperature increases (+4°C), A. minutum growth was enhanced, with no measurable physiological stress response. However, under an acute increase in temperature (+12°C), A. minutum growth declined, photosynthetic efficiency (FV/FM) was impaired, and enhanced oxidative stress was observed. These physiological responses were accompanied by increased DMS and DMSO concentrations followed by decreased DMSP concentrations. At this higher temperature, we observed a cascading stress response in A. minutum, which was initiated 6 h after the start of the experiment by a spike in DMS and DMSO concentrations and a rapid decrease in FV/FM. This was followed by an increase in reactive oxygen species (ROS) and an abrupt decline in DMS and DMSO on day 2 of the experiment. A subsequent decrease in DMSP coupled with a decline in the growth rate of both A. minutum and its associated total bacterial assemblage coincided with a shift in the composition of the A. minutum microbiome. Specifically, an increase in the relative abundance of OTUs matching the genus Oceanicaulis (17.0%), Phycisphaeraceae SM1A02 (8.8%) and Balneola (4.9%) as well as a decreased relative abundance of Maribacter (24.4%), Marinoscillum (4.7%) and Seohaeicola (2.7%), were primarily responsible for differences in microbiome structure observed between temperature treatments. These shifts in microbiome structure are likely to have been driven by either the changing physiological state of A. minutum cells, shifts in biogenic sulfur concentrations, or a combination of both. We suggest that these results point to the significant effect of heatwaves on the physiology, growth and microbiome composition of the red-tide causing dinoflagellate A. minutum, as well as potential implications for biogenic sulfur cycling processes and marine DMS emissions. [ABSTRACT FROM AUTHOR] more...

Abstract The content and distribution of biogenic silica (BSi) in sediments, as effective proxies for marine paleo-productivity and sedimentary environment evolution studies, has significant seasonal and event-based differences. Based on measurements of BSi content in the seafloor sediments acquired during three surveys in winter and before and after typhoons in summer in the Fujian-Zhejiang coastal mud deposition center (MDC-ZFC), respectively, the seasonal and event-based (typhoon process) differences of BSi in seafloor sediments are discussed by combining with data of the sediments grain sizes and the abundances of dominant diatom species. Conceptual models of the modern sedimentary environment (including BSi) are summarized. The study results show that the BSi in the seafloor sediments in the study region is relatively low, generally less than 1%. Generally, the BSi in the winter seafloor sediments is lower than that under normal summer sea conditions and the BSi in the sediments after the summer typhoons is higher than that under normal summer sea conditions. The differences in the origin of biogenic siliceous materials (seasonal growth of siliceous organisms) and the marine hydrodynamic environment (such as seafloor sediment resuspension and elutriation caused by strong marine hydrodynamic processes) are the major factors for different relative BSi content. The seasonal and event-based variations of BSi have important significance in paleo-oceanography and event sedimentology studies. Highlights • The content and distribution of BSi have seasonal and typhoon event differents. • Plankton growth and sedimentary dynamics are control factors of BSi distribution. • BSi studies have importance application in plaeoceanography sedimentology study. [ABSTRACT FROM AUTHOR] more...

Graphical abstract Highlights • BioMnO x had an unprecedented PMS activation efficiency, 3-fold faster than 3D α-Mn 2 O 3. • 100% phenol at 40 min and 99.4% TC at 60 min were degraded in BioMnO x /PMS system. • BioMnO x had a wide pH working range 3.0–9.0 and excellent long-term stability. • 1O 2 was the dominant reactive oxygen species for pollutant degradation over BioMnO x. • Different TC degradation pathway by 1O 2 was proposed vs. by OH radical. Abstract From the view of environment and easy availability, to develop the most efficient manganese oxide for peroxymonosulfate (PMS) activation is of great importance for the degradation of recalcitrant organic pollutants. In this study, biogenic manganese oxide (BioMnO x) exhibited an unprecedented efficiency than the most efficient 3D α-Mn 2 O 3 prepared by chemical method. 100% of phenol degradation at 40 min and 99.4% of tetracycline removal at 60 min were achieved over BioMnO x with PMS, which was 3-fold faster than 3D α-Mn 2 O 3. BioMnO x also has an excellent long-term stability and good performance toward the pollutants degradation at a wide pH range of 3.0–9.0. Most importantly, 1O 2 was identified as the primary reactive species in BioMnO x /PMS system based on the trapping experiment and EPR analysis. The PMS activation over BioMnO x should follow a self-decomposition and energy quenching mechanism instead of electron transfer process as confirmed by the XPS analysis. Finally, the degradation pathways of tetracycline and phenol by 1O 2 over BioMnO x were proposed according to HPLC and HPLC-MS results, which are greatly different from that by OH oxidation in the literature. [ABSTRACT FROM AUTHOR] more...

Abstract Chemical and isotopic data for water co-extracted with hydrocarbons in oil and gas fields are commonly used to examine the source of the formation water and possible impacts on groundwater in areas of oil and gas development. Understanding the geochemical variability of oil-field water could help to evaluate its origin and delineate possible contamination of shallow aquifers in cases where oil-field water is released to the environment. Here we report geochemical and multiple isotope (H, C, O, Sr, Ra) data from 22 oil wells, three sources of produced water that are disposed of in injection wells, and two surface disposal ponds in four oil fields in the southern San Joaquin Valley, California (Fruitvale, Lost Hills, North and South Belridge). Correlations between Cl and δ18O, as well as other ions, and gradual increases in salinity with depth, indicate dilution of one or more saline end-members by meteoric water. The saline end-members, represented by deep samples (610 m–2621 m) in three oil-bearing zones, are characterized by Na Cl composition, near-seawater Cl concentrations (median 20,000 mg/L), enriched δ18O H 2 O (median 3.4‰), high ammonium (up to 460 mg-N/L), and relatively high radium activity (226Ra+228Ra = 12.3 Bq/L). The deepest sample has low Na/Cl (0.74), high Ca/Mg (5.0), and low 87Sr/86Sr (0.7063), whereas the shallower samples have higher Na/Cl (0.86–1.2), Ca/Mg near 1, and higher 87Sr/86Sr (∼0.7083). The data are consistent with an original seawater source being modified by various depth and lithology dependent diagenetic processes. Dilution by meteoric water occurs naturally on the east side of the valley, and in association with water-injection activities on the west side. Meteoric-water flushing, particularly on the east side, results in lower solute concentrations (minimum total dissolved solids 2730 mg/L) and total radium (minimum 0.27 Bq/L) in oil-field water, and promotes biodegradation of dissolved organic carbon and hydrocarbon gases like propane. Acetate concentrations and δ13C of dissolved inorganic carbon indicate biogenic methane production occurs in some shallow oil zones. Natural and human processes produce substantial variability in the geochemistry of oil-field water that should be considered when evaluating mixing between oil-field waters and groundwater. The variability could result in uncertainty as to detecting the potential source and impact of oil-field water on groundwater. Highlights • Original seawater source modified by diagenetic processes and meteoric-water mixing. • Meteoric water from natural recharge and fluid injection. • Meteoric-water flushing promotes hydrocarbon biodegradation and methanogenesis. • Ammonium occurs at high concentrations in oil-field water. [ABSTRACT FROM AUTHOR] more...

Abstract Biogenic habitats play important roles in shallow-water ecosystems, but their roles in deeper waters are less well-studied. We quantitatively assessed 19 glass sponge reefs in the Salish Sea for live reef-building sponge cover and biodiversity, explored potential drivers behind variation observed among reefs, and quantified individual and collective roles the reefs play in filtration and carbon removal. The reefs support diverse and abundant communities of invertebrates and fish, with 115 unique taxonomic groups observed. Sponge cover varied widely between reefs: percent live reef-building sponge cover ranged from 0.2 to 17.5% and proportion of live reef habitat category ranged from 0.2 to 92%. These differences were predominantly driven by the seabed terrain characteristics such as seafloor rugosity, curvature, and depth; human pressure measures explored in this study − density of anthropogenic objects and fishing footprint over the past 17 years – did not mask the natural influence of seabed terrain. The difference in sponge cover between the reefs led to wide variation in ecosystem function with individual reefs processing between 465 and 47,300 L/m2 per day. Collectively, each day the 19 reefs filter 1.04 × 1011 L of water which corresponds to 1% of the total water volume in Strait of Georgia and Howe Sound combined. The reefs remove up to 1 g of carbon per m2 per day, comparable to carbon sequestration rates reported for terrestrial old growth forests and to "blue carbon" sequestration rates by marine vegetation. Implications for sponge reef conservation and monitoring are discussed. Highlights • 19 glass sponge reefs in the Salish Sea vary in live sponge cover. • Live sponge cover is driven by seabed terrain despite significant human pressure. • Over 115 unique taxonomic groups of invertebrates and fish live on the reefs. • Reefs collectively filter 1.04 × 1011 L of water daily, 1% of basin water volume. • Reefs remove up to 1 gC/m2 daily, comparable to terrestrial and kelp forests. [ABSTRACT FROM AUTHOR] more...

This study investigates chromium isotope variations ( δ 53 Cr) and REE patterns in present-day biogenic carbonates and ocean waters from Lady Elliot Island (LEI) located in the southern Great Barrier Reef (GBR), Australia, which is one of the world's largest carbonate-producing shelf ecosystems. Our results from thoroughly cleaned biogenic carbonates collected at LEI, with no detectable evidence for lithogenic Cr and/or Mn–Fe oxide coating contamination, revealed a systematic and statistically significant correlation ( r 2 = 0.83 , p < 0.05 ) between δ 53 Cr and cerium anomaly (Ce/Ce*) data in molluscan shells (i.e., gastropods). This in turn implies a redox-controlled incorporation of Cr from seawater into a shell during mineralization mediated by the organism. In particular, shells with higher δ 53 Cr values, which approach the Cr isotope composition of local seawater, tend to be associated with more negative Ce/Ce*. Importantly, the intercept of the above δ 53 Cr vs. Ce/Ce* correlation points to the Cr isotope composition of local ocean water, which has an average δ 53 Cr of + 0.82 ± 0.13 ‰ (2 σ , relative to SRM 979). These findings thus indicate that the above multi-proxy approach could be used to reconstruct the δ 53 Cr signature of local paleo-seawater based on Ce/Ce* and δ 53 Cr data in a set of well-preserved fossil skeletal carbonates (i.e., molluscan shells) collected at a specific site. Interestingly, the only calcifying organism from LEI that yielded identical δ 53 Cr vs. Ce/Ce* values as those in ambient ocean water was a microbial calcitic carbonate produced by red coralline algae ( Lithothamnion sp.). This organism thus seems to incorporate Cr isotopes and REE from seawater without additional biological discrimination and/or isotope fractionation effects. Considering that calcite is a more stable CaCO 3 polymorph during post-depositional alternation and diagenetic stabilization of marine carbonates (compared to aragonite), the fossil counterparts of these algal-microbial carbonates (microbialites) might thus represent ideal natural archives of the paleo-seawater δ 53 Cr and Ce/Ce* variations over geological time. Finally, our compilation of δ 53 Cr data from recent marine biogenic carbonates originating from the main oceanic provinces (South/North Pacific, South/North Atlantic, Caribbean, Mediterranean Sea) confirms that marine carbonates tend to be systematically enriched in light Cr isotopes relative to local ocean waters. Trace element constraints, however, indicate that some of these shifts to lower δ 53 Cr values (i.e., approaching −0.1 per mil) are related to a presence of lithogenic Cr in the shells, causing a diagenetic overprint of the primary marine δ 53 Cr signal. [ABSTRACT FROM AUTHOR] more...

The results of long-term studies on zooplankton from Syamozero Lake, South Karelia, have been analyzed. The relationship between the quantitative indices of the zooplankton community and the value and dynamics of the biogenic load on the lake is established. The redistribution of the ratio of the major groups and dominant zooplankton species, the decrease in the Shannon diversity index, the increase in the Mäemets trophic state index, and with the increase in the abundance of indicator species of higher nutrient supply have been determined. The effect of anthropogenic factors on the population characteristics of the zooplankton community and changes in the trophic status of the lake with a high resource potential have been found. [ABSTRACT FROM AUTHOR] more...

We present the first dataset of meiofauna associated with vermetid reefs (biogenic constructions of Mediterranean intertidal habitat) in two areas along the northern coast of Sicily, Italy. The vermetid reefs are characterized by a horizontal extension from the shore towards the open sea and can be divided into three zones (the inner margin, the cuvette zone and the outer margin) which differ in hydrodynamic features. We studied the spatial distribution of meiofauna along the horizontal axis of the vermetid reefs, investigating the communities inhabiting the sediment inside cuvettes (shallow pools inside the “cuvette zone”) located between the inner and the outer margins of the reefs. We observed an increase in meiofaunal abundance from the inner to the outer part of the reef (from 1808 ± 80 to 2992 ± 512 ind. 100 cm−2) in both areas. Moreover, we studied meiofaunal communities associated with the most abundant macroalgae (Cystoseira sp., Jania rubens, Palisada perforata, Dictyota sp. and Padina pavonica) living on the reefs, investigating the influence of habitat size (biomass) and identity (complexity) of macroalgae. We found that meiofauna varied in abundance (from 446 ± 51 to 1758 ± 231 ind. 100 cm−2 on P. perforata and Cystoseira sp., respectively), on different macroalgae, and that the habitat size significantly influenced these abundances, but its effect was dependent on macroalgal identity. In fact, we observed a positive correlation between meiofaunal abundance and algal complexity (fractal dimension). The high algal cover in the “cuvette zone” of the reefs could contribute to make this zone more suitable for meiofauna, in particular close to the outer margin where we found more complex macroalgae (i.e. Cystoseira sp.). These results confirm that vermetid reefs, with their structural complexity, may play an important role in structuring benthic fauna in intertidal habitats. [ABSTRACT FROM AUTHOR] more...

Although tellurite is highly toxic to organisms, elemental tellurium nanomaterials (TeNMs) have many uses. The microbe-mediated reduction of tellurite to Te(0) has been shown to be a green and cost-effective approach for turning waste into wealth. However, it is difficult to tune the morphology of biogenic nanomaterials. In this study, a series of experiments was conducted to investigate the factors influencing tellurite reduction by the tellurite-reducing bacterium Lysinibacillus sp. ZYM-1, including pH, tellurite concentration, temperature, and heavy metal ions. The optimal removal efficiency of tellurite was respectively achieved at pH 8, 0.5 mM tellurite, and 40 °C. All of the tested metal ions retarded the reduction of tellurite, especially Cd2+ and Co2+, which completely inhibited its reduction. Further characterization of the biogenic TeNMs indicated that their morphology could be tuned by the tellurite concentration, pH, temperature, and organic solvents used. Regular Te nanosheets were produced using 5 mM tellurite. The TeNMs were primarily synthesized in the cell membrane. Hexagonal Te nanoplates, nanorods, nanoflowers, and nanobranches were synthesized when combining membrane fractions with tellurite and NADH. The diverse morphologies are assumed to be induced by the synergy between the reduction kinetics and the protein structure. Therefore, this study confirmed that the bacterium can tune the morphology of TeNMs, broadening the potential application of biogenic TeNMs. [ABSTRACT FROM AUTHOR] more...

The Beijing area has suffered from severe air pollution in recent years, including ozone pollution in the summer. In addition to the anthropogenic emissions inventory, understanding local ozone pollution requires a reliable biogenic volatile organic compound (BVOC) emission inventory. Forest coverage rose from 20.6 to 35.8% from 1998 to 2013 in Beijing according to the National Forest Resource Survey (NFRS), and accurate representations of land cover for recent years is crucial for estimating BVOC emissions and their impacts on air quality. In this study, we established a high-resolution BVOC emission inventory in Beijing using the Model of Emissions of Gases and Aerosols from Nature (MEGAN) v2.1 with three independent leaf area index (LAI) products and three independent land cover products. Various combinations of the Global LAnd Surface Satellite (GLASS), Moderate-Resolution Imaging Spectroradiometer (MODIS) MCD15, and GEOland (GEO) v2 LAI datasets and the Finer Resolution Observation and Monitoring of Global Land Cover (FROM-GLC), MODIS MCD12Q1 plant functional type (PFT) products, and Climate Change Initiative Land Cover (CCI LC) products are used in five model sensitivity experiments (E1-E5), and the experiment using the FROM-GLC with the highest spatial resolution of 30 m and GLASS LAI products was treated as the baseline. These sensitivity calculations were driven by hourly, 3 km meteorological fields from the Weather Research and Forecasting (WRF) model. The following results were obtained: (1) according to the baseline estimate, the total amount of BVOC emissions is 75.9 Gg for the Beijing area, and isoprene, monoterpenes, sesquiterpenes and other VOCs account for 37.6, 14.6, 1.8 and 46% of the total, respectively. Approximately three-quarters of BVOC emissions occur in the summer. (2) According to the sensitivity experiments, the LAI input does not significantly affect the BVOC emissions. Using MODIS MCD15Q1 and GEO v2 LAI led to slight declines of 2.6 and 1.4%, respectively, of BVOC emissions in the same area. (3) The spatial distribution of PFTs from different inputs strongly influenced the spatial distribution of BVOC emissions. Furthermore, the cross-walking table for converting land cover classes to PFTs also has a strong impact on BVOC emissions; the sensitivity experiments showed that the estimate of BVOC emissions by CCI LC ranged from 42.1 to 70.2 Gg depending on the cross-walking table used. [ABSTRACT FROM AUTHOR] more...

The Black Sea is the largest meromictic basin, in the bottom sediments of which a powerful biogenic process of sulfide production occurs. The goal of the present work was to obtain data on phylogenetic diversity of the sulfur cycle microorganisms (sulfate-reducing and sulfur-oxidizing bacteria) in the Black Sea coastal gas-saturated bottom sediments. The samples were collected in the Chersonesus (Blue) Bay near Sevastopol from whitish bacterial mats of sulfurettes, and from the upper layer of the nearby seabed. Using DNA isolated from the native samples and obtained enrichment cultures, PCR analysis was performed with oligonucleotide primers specific to the fragments of the 16S rRNA genes of the main subgroups of sulfatereducing bacteria (SRB) and to the fragments of the dsrB gene (both reductive and oxidative types), encoding the β-subunit of dissimilatory (bi)sulfite reductase, the key enzyme in the sulfur cycle, inherent in both sulfate- reducing and sulfur-oxidizing microorganisms. The presence of 16S rRNA gene fragments specific to the genera Desulfobacterium, Desulfobacter, Desulfococcus-Desulfonema-Desulfosarcina, and Desulfovibrio-Desulfomicrobium was detected in the DNA samples isolated from coastal bottom bacterial mats. Usage of denaturing gradient gel electrophoresis (DGGE) with subsequent sequencing of reamplified dsrB gene fragments revealed that according to deduced amino acid sequences encoded by the dsrB gene (reductive type), SRB from the coastal gas-saturated bottom sediments of the Black Sea had the highest homology (92−99%) with the dsrB gene of cultured SRB belonging to the genera Desulfovibrio, Desulfatitalea, Desulfobacter, and Desulfobacterium, as well as with uncultured SRB strains from various marine habitats, such as bottom sediments of the Northern and Japanese seas. Deduced amino acid sequences encoded by the oxidative dsrB gene had the highest homology (90−99%) with the relevant sequences of the genera Thiocapsa, Thiobaca, Thioflavicoccus, and Thiorhodococcus. [ABSTRACT FROM AUTHOR] more...

The Gammaproteobacteria are widely and abundantly distributed in various environments, and they play important roles in the geochemical cycles of biogenic elements (e.g., C, N and S) in the ecosystems. Previous studies showed that Gammaproteobacteria dominate in saline and hypersaline lakes. However, little is known on how salinity influences gammaproteobacterial community composition and their ecological functions (i.e., organic carbon degradation). In this study, we investigated the gammaproteobacterial diversity and carbon utilization and their response to salinity in six saline/hypersaline lakes and one freshwater lake on the Qinghai-Tibetan Plateau (QTP). The results indicated that the gammaproteobacterial community composition was mainly influenced by the salinity of the studied QTP lakes. Salinity was also a key environmental factor influencing the carbon utilization ability of Gammaproteobacteria: within one genus (e.g., Halomonas, Pseudoalteromonas, Vibrio) the strains retrieved from low-salinity environments had stronger carbon utilization ability than their counterparts from high-salinity environments; within one genus, the strains isolated from lakes with different salinity shared similar carbon utilization preference, indicating that species belonging to the same genus may execute similar ecological functions in the environments regardless of salinity. [ABSTRACT FROM AUTHOR] more...