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Summary: Spatio-temporal variability of sediment-mediated methane (CH4) production in freshwater lakes causes large uncertainties in predicting global lake CH4 emissions under different climate change and eutrophication scenarios. We conducted extensive sediment incubation experiments to investigate CH4 fluxes in Lake Stechlin, a deep, stratified temperate lake. Our results show contrasting spatial patterns in CH4 fluxes between littoral and profundal sites. The littoral sediments, ∼33% of the total sediment surface area, contributed ∼86.9% of the annual CH4 flux at the sediment-water interface. Together with sediment organic carbon quality, seasonal stratification is responsible for the striking spatial difference in sediment CH4 production between littoral and profundal zones owing to more sensitive CH4 production than oxidation to warming. While profundal sediments produce a relatively small amount of CH4, its production increases markedly as anoxia spreads in late summer. Our measurements indicate that future lake CH4 emissions will increase due to climate warming and concomitant hypoxia/anoxia.

Summary: The recent surge in dam construction has sparked debates regarding their contribution to carbon neutrality and food security, focusing on trade-offs between production benefits and ecological drawbacks. However, how dams affect carbon emissions and land cover changes, including their spatial differentiations, remains unclear. We quantified spatiotemporal variations in carbon emissions and storage of 137 large dams in China from 1992 to 2020, resulting from land cover change in potentially affected areas. We observed a lesser increase in carbon emissions and a more pronounced increase in carbon storage driven by forest conservation and regeneration within dam-affected areas compared to unaffected areas. Additionally, we noticed an increased grain yield in nearby areas potentially due to increased water availability. Our findings highlight the importance of considering land cover change when assessing carbon neutrality or grain yield at regional and national scales. This study provides useful insights into optimizing dam locations to mitigate future carbon emissions effectively.

The primary objective of the National Aeronautics and Space Administration (NASA) Surface Biology and Geology (SBG) mission is to measure biological, physical, chemical, and mineralogical features of the Earth's surface, realizing a key conceptual component of the envisioned NASA Earth System Observatory (ESO). SBG is planned to launch as a two‐platform mission in the late 2020s, the first of the ESO satellites. Targeted science and applications objectives based on observations of the Earth's SBG helped to define the mission architecture and instrument capabilities for the SBG mission concept. These objectives further drove the need for enabling change detection and trending of surface biological and geological features. These needs implied fundamental calibration goals to achieve the necessary science data quality characteristics. To meet those goals, calibration and validation pre‐launch and on‐orbit methods formed a basis of the calibration and validation concept, including the combined use of on‐board references, vicarious techniques, and routine lunar imaging. International collaboration with space agencies in other countries, an important feature of the recommended SBG mission architecture, uncovered and emphasized the need for inter‐calibration techniques that underscored the importance of collaborative instrument characterization data sharing and the use of common calibration references that are International System of Units (SI) traceable in pre‐launch and post‐launch on orbit calibration mission phases. International collaboration through the use of terrestrial and aquatic networks on six continents for vicarious calibration and validation activities will further assure necessary science data quality while in orbit. Plain Language Summary: The NASA Surface Biology and Geology (SBG) mission will measure biological, physical, chemical, and mineralogical features of the Earth's surface. Targeted science and applications objectives helped to define the mission architecture and instrument capabilities for the SBG mission concept. These objectives also defined the need to detect changes and trends in biological and geological process on the face of the Earth. To meet these needs and objectives required fundamental calibration and validation concepts to achieve the necessary science data quality characteristics. These concepts included methods and resources used before and after launch. International collaboration with space agencies in other countries, an important feature of the recommended SBG mission architecture, also revealed the need for strong collaboration between agencies. This includes maintaining commonality in terminology, methods, algorithms and references and through the shared use of surface measurement networks on six continents. Key Points: Overviews cal/val ideas recommended for the Surface Biology and Geology (SBG) mission, with some consideration for collaborating with multiple contemporary missionsLooks at approaches to inter‐calibration of multiple Earth orbiting sensorsSurveys what cal/val resources and techniques are currently available or may be available to the SBG mission later in this decade [ABSTRACT FROM AUTHOR]

Nitrogen is a critical component of the economy, food security, and planetary health. Many of the world's sustainability targets hinge on global nitrogen solutions, which, in turn, contribute lasting benefits for: (i) world hunger; (ii) soil, air and water quality; (iii) climate change mitigation; and (iv) biodiversity conservation. Balancing the projected rise in agricultural nitrogen demands while achieving these 21st century ideals will require policies to coordinate solutions among technologies, consumer choice, and socioeconomic transformation.

Nitrogen is a critical component of the economy, food security, and planetary health. Many of the world's sustainability targets hinge on global nitrogen solutions, which, in turn, contribute lasting benefits for: (i) world hunger; (ii) soil, air and water quality; (iii) climate change mitigation; and (iv) biodiversity conservation. Balancing the projected rise in agricultural nitrogen demands while achieving these 21st century ideals will require policies to coordinate solutions among technologies, consumer choice, and socioeconomic transformation.

Summary: We investigated a nature-based solution (NbS) via incorporating biocrust into alfalfa-maize intercropping system to test carbon sequestration in seriously eroded agricultural soils. Field investigation showed that the NbS (moss-dominated biocrust + intercropping) massively lowered surface soil erosion by 94.5% and soil carbon (C) and nitrogen (N) loss by 94.7 and 96.8% respectively, while promoting rainwater interception by 82.2% relative to bare land (CK). There generally existed positive interactions between biocrust and cropping in the integrated standing biodiversity system. Enhanced plant biomass input into soils substantially promoted soil fungal community diversity and abundance under NbS (p

Summary: Periphytic biofilms (PB) at the soil-water interface contributes 7–38% of the methane emission from rice paddies, yet the biogeographical mechanism underlying and affecting the process remain elusive. In this study, rice fields along an edapho-vclimatic gradient were sampled, and the environmental drivers affecting distribution of methanogenic and methanotrophic communities were evaluated. The methanogenic and methanotrophic communities at soil-water interface showed less complex inter/intra-generic interactions than those in soil, and their relative abundances were weakly driven by spatial distance, soil organic carbon, soil total nitrogen and pH. The nutrient supply and buffering capacity of extracellular polymeric substance released by PB reduced their interaction and enhanced the resilience on edaphic environment changes. Climate affected soil metal content, extracellular polymeric substance content, and thus the methane-related communities, and caused geographical variation in the impacts of PB on methane emissions from rice paddies. This study facilitates our understanding of geographical differences in the contribution of PB to methane emission.

The unfolding climate crisis is in many respects a human issue, one caused by anthropogenic emissions of CO2 to the atmosphere, and that can only be solved through a concerted effort across all sectors of society. In this prospective synthesis, I explain how expanding the scope of biogeochemical research would lead to a more rigorous and impactful climate change mitigation and adaptation agenda. Focusing on biogeochemistry as an area of interdisciplinary convergence, I review theories and empirical studies in the environmental and social sciences, to distill five principles and three phases of implementation for sustainable carbon capture projects. I discuss how land conservation, management, and restoration might be coordinated to prepare for climate change and to achieve multiple social and ecological benefits, including enhanced carbon drawdown and permanence on land. On the conservation front, the abundance of threatened plant and animal species spatially correlates with the distribution of carbon- and water-rich habitats within and across key regions, which can be prioritized for biodiversity protection with major climatic benefits. On the management front, long-term records of socioecological change warrant a revision of current models for sustainable forestry and agriculture in favor of decentralized system-specific prescriptions, including interventions where organic or inorganic carbon capture may improve wood and food production under future climate scenarios. On the restoration front, experiments in degraded landscapes reveal mechanisms of carbon stabilization, such as iron-coordination of organic complexes, which amplify the benefits of ecological succession and lead to carbon accumulation beyond thresholds predicted for undisturbed ecosystems. These examples illustrate the potential for innovation at the intersection of basic and applied biogeoscience, which could accelerate atmospheric carbon capture through new discoveries and collective action. [ABSTRACT FROM AUTHOR]

Summary: Untreated mining wastes and improper disposal of high-tech devices generate an environmental increase of bioavailable metalloids, exerting stress on autochthonous microbial populations. Tellurium is a metalloid, an element with raising economic importance; nevertheless, its interaction with living organisms is not yet fully understood. Here we characterized aerobic heterotrophic bacteria, isolated from high metal-content mining residues, able to resist/reduce tellurite into tellurium structures and to determine the presence of confirmed tellurite resistance genetic determinants in resistant strains. We identified over 50 tellurite-resistant strains, among 144 isolates, eight strains reduced tellurite to tellurium at different rates, with the concomitant production of tellurium deposits. Most tellurite resistance genes were found in strains from Bacillales, with the prevalence of genes of the ter operon. This work demonstrated that bacterial isolates, from environments with a persistent selective pressure, are potential candidates for uncovering strategies for tellurite resistance and/or production of valuable Te-containing materials.

Summary: Microbial inoculations contribute to reducing agricultural systems' environmental footprint by supporting sustainable production and regulating climate change. However, the indirect and cascading effects of microbial inoculants through the reshaping of soil microbiome are largely overlooked. By discussing the underlying mechanisms of plant- and soil-based microbial inoculants, we suggest that a key challenge in microbial inoculation is to understand their legacy on indigenous microbial communities and the corresponding impacts on agroecosystem functions and services relevant to climate change. We explain how these legacy effects on the soil microbiome can be understood by building on the mechanisms driving microbial invasions and placing inoculation into the context of ecological succession and community assembly. Overall, we advocate that generalizing field trials to systematically test inoculants' effectiveness and developing knowledge anchored in the scientific field of biological/microbial invasion are two essential requirements for applying microbial inoculants in agricultural ecosystems to tackle climate change challenges.

Summary: This work designs a heatwave with a calorimeter to analyze the response of soils from oak forest ecosystems to increasing temperature from 20°C to 60°C and to cooling from 60°C to 20°C. Calorimetry measures the heat rate of the soil organic matter decomposition and the response to increasing and decreasing temperatures directly. It was applied to soil samples representing different soil horizons with organic matter at different degree of decomposition given by their heat of combustion, calculated by differential scanning calorimetry. Results showed temperature-dependent decomposition rates from 20°C to 40°C or 50°C typical for enzymatic activity. From 40°C to 60°C, changes in the rates are less predictable. Data analysis during cooling showed that all samples suffered losses of their enzymatic capacity and that only those with the heat of combustion values close to that of carbohydrates resisted the heat wave.

Abstract Nitrogen is a critical component of the economy, food security, and planetary health. Many of the world's sustainability targets hinge on global nitrogen solutions, which, in turn, contribute lasting benefits for (i) world hunger; (ii) soil, air, and water quality; (iii) climate change mitigation; and (iv) biodiversity conservation. Balancing the projected rise in agricultural nitrogen demands while achieving these 21st century ideals will require policies to coordinate solutions among technologies, consumer choice, and socioeconomic transformation.

Magnetotactic bacteria (MTB) belong to several phyla. This class of microorganisms exhibits the ability of magneto-aerotaxis. MTB synthesize biominerals in organelle-like structures called magnetosomes, which contain single-domain crystals of magnetite (Fe3O4) or greigite (Fe3S4) characterized by a high degree of structural and compositional perfection. Magnetosomes from dead MTB could be preserved in sediments (called fossil magnetosomes or magnetofossils). Under certain conditions, magnetofossils are capable of retaining their remanence for millions of years. This accounts for the growing interest in MTB and magnetofossils in paleo- and rock magnetism and in a wider field of biogeoscience. At the same time, high biocompatibility of magnetosomes makes possible their potential use in biomedical applications, including magnetic resonance imaging, hyperthermia, magnetically guided drug delivery, and immunomagnetic analysis. In this review, we attempt to summarize the current state of the art in the field of MTB research and applications. [ABSTRACT FROM AUTHOR]

Summary: The biological carbon pump, in which carbon fixed by photosynthesis is exported to the deep ocean through sinking, is a major process in Earth's carbon cycle. The proportion of primary production that is exported is termed the carbon export efficiency (CEE). Based on in-lab or regional scale observations, viruses were previously suggested to affect the CEE (i.e., viral “shunt” and “shuttle”). In this study, we tested associations between viral community composition and CEE measured at a global scale. A regression model based on relative abundance of viral marker genes explained 67% of the variation in CEE. Viruses with high importance in the model were predicted to infect ecologically important hosts. These results are consistent with the view that the viral shunt and shuttle functions at a large scale and further imply that viruses likely act in this process in a way dependent on their hosts and ecosystem dynamics.

Summary: Bioweathering mediated by microorganisms plays a significant role in biogeochemical cycles on global scales over geological timescales. Single processes induced by specific taxa have been described but could rarely be demonstrated for complex communities that dominate whole landscapes. The recently discovered grit crust of the coastal Atacama Desert, which is a transitional community between a cryptogamic ground cover and a rock-bound lithic assemblage, offers the unique chance to elucidate various bioweathering processes that occur simultaneously. Here, we present a bioweathering scenario of this biocenosis including processes such as penetration of the lithomatrix, microbial responses to wet-dry cycles, alkalinolysis, enzyme activity, and mineral re-localization. Frequently occurring fog, for example, led to a volume increase of microorganisms and the lithomatrix. This, together with pH shifts and dust accumulation, consequently results in biophysical breakdown and the formation of a terrestrial protopedon, an initial stage of pedogenesis fueled by the grit crust.

The environmental influence of the Three Gorges Reservoir (TGR) on the Changjiang River has been widely studied since the Three Gorges Dam (TGD) began operation in 2003. However, the changes in water chemistry in the reservoir in response to damming effect variations are poorly documented in the area of this large reservoir. The results suggest that in comparison to the water chemistry before the TGR operation, the inflow concentrations of Mg2+, K+, Na+ and Cl− increased in the TGR, and the abundance of Ca2+ and HCO3- decreased in the inflow in the period after the TGR filling as a result of climate change and human activities in the Changjiang River basin. The ionic composition in the TGR is primarily controlled by contributions from the upstream region of the Changjiang River but was modified by the interaction between water and rocks within the TGR. The concentrations of most major ions as well as the equivalent ratios of the major ions increased in the TGR after the operation of TGD. This change yielded a 6% increase in the major ion loading downstream of the TGD. The Three Gorges area strongly contributes to the increase in ion loading in the TGR due to enhanced water and rock interactions in comparison with the period before TGD operation.

Background: HIV/AIDS is frequently associated with opportunistic diseases such as leishmaniasis. Hence, the co-infection HIV-Leishmania spp. is the result of the geographical overlap between leishmaniasis and HIV/AIDS cases. To the best of our knowledge, this is the first report describing the spatial distribution of HIV-Leishmaniasis co-infection in Morocco where both infections are endemic. Methods: In the current study, we discuss the HIV-Leishmania spp. co-infection vulnerability in Morocco by using the cartography tools. Thus, epidemiological data of both infections (Leishmaniasis and HIV/AIDS) in different administrative regions of Morocco were collected and co-registered for Digital maps making. Results & conclusion: The results showed a high risk of HIV-Leishmania infantum co-infection in northern and central regions in Morocco. These results should be taken into account for efficient control strategies and epidemiological surveillance of HIV –Leishmania spp. co-infection in Morocco.

Chitosan, a natural carbohydrate polymer, has long been investigated for drug delivery and medical applications due to its biodegradability, biocompatibility and low toxicity. The micro/nanoparticulate forms of chitosan are reported to enhance the efficiency of drug delivery with better physicochemical properties including improved solubility and bioavailability. This polymer is known to be biodegradable and biocompatible; however, crosslinked chitosan particles may not be biodegradable. Crosslinkers (e.g., tripolyphosphate and glutaraldehyde) are needed for efficient micro/nanoparticle formation, but it is not clear whether the resultant particles are biodegradable or able to release the encapsulated drug fully. To date, no studies have conclusively demonstrated the complete biodegradation or elimination of chitosan nanoparticles in vivo. Herein we review the synthesis and degradation mechanisms of chitosan micro/nanoparticles frequently used in drug delivery especially in pulmonary drug delivery to understand whether these nanoparticles are biodegradable.

‘Capable-of-being-shaped’ synthetic compounds are prevailing today over horn, bone, leather, wood, stone, metal, glass, or ceramic in products that were previously left to natural materials. Plastic is, in fact, economical, simple, adaptable, and waterproof. Also, it is durable and resilient to natural degradation (although microbial species capable of degrading plastics do exist). In becoming a waste, plastic accumulation adversely affects ecosystems. The majority of plastic debris pollutes waters, accumulating in oceans. And, the behaviour and the quantity of plastic, which has become waste, are rather well documented in the water, in fact. This review collects existing information on plastics in the soil, paying particular attention to both their degradation and possible re-uses. The use of plastics in agriculture is also considered. The discussion is organised according to their resin type and the identification codes used in recycling programs. In addition, options for post-consumer plastics are considered. Acknowledged indicators do not exist, and future study they will have to identify viable and shared methods to measure the presence and the degradation of individual polymers in soils.

Cultivable halophilic microorganisms were isolated and identified from saline and alkaline-sodic soils: Cuatro Cienegas, Sayula and San Marcos lakes. Physicochemical characteristics of soils were determined to understand the relationship between those and the microorganisms isolated. The Cuatro Cienegas soils had a neutral pH, EC of 2.3–8 dS cm−1, classified as moderately saline. Whereas, the soils from Sayula and San Marcos lakes, had an alkaline pH, EC 15 to 65 dS m−1, typical of saline-sodic. We identified 23 cultivable halophilic bacteria using 16s rDNA, being Halobacillus sp., Marinococcus sp., and Alkalibacillus sp. the predominant genus by culture dependent approach. We found a correlation between the soils anion and cation content with the occurrence of different genus of halophilic bacteria in each studied site. Alkalibacillus sp. was predominant in Sayula and San Marcos lakes and was related to the high Na+ content; while Bacillus sp. and Halobacillus sp. were predominant in Cuatro Cienegas, their occurrence was related to a high content of Ca2+, Mg2+, and SO42-.

Anthropogenic use of high density, toxic elements results in marine pollution which is bio-accumulating throughout marine food webs. While there have been several studies in various locations analyzing such elements in fish, few have investigated patterns in these elements and their isotopes in terms of ocean depth, and none have studied the greatest depth zones. We used a flame atomic absorption spectrophotometer-hydride system and an inductively coupled plasma-mass spectrometer to determine concentrations of the high-density elements arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), selenium (Se), plus the light-metal barium (Ba), in fish ranging from bathyal (1000 m in Monterey Bay) to upper hadal zones (6500–7626 m in the Kermadec and Mariana Trenches) in the Pacific Ocean. Five species of fish—including the Mariana Trench snailfish, the world's deepest known fish newly discovered—were analyzed for patterns in total element concentration, depth of occurrence, Se:Hg ratio, plus mercury isotopes in the deepest species. Co and As levels decreased with depth. In the Mariana Trench, Pb, Hg, Cd, and Cu were higher than in all other samples, and higher in those plus Ba than in the Kermadec Trench. The latter samples had far higher Ni and Cr levels than all others. Mercury relative isotope analysis showed no depth trends in the deepest species. Se:Hg showed a large molar excess of Se in bathyal flatfish species. These patterns indicate that exposures to pollutants differ greatly between habitats including trenches of similar depths.

Carbon fixation microorganisms (CFMs) are important components of the soil carbon cycle. However, the global distribution of CFMs and whether they will exceed the environmental tipping points remain unclear. According to the machine learning models, total carbon content, nitrogen fertilizer, and precipitation play dominant roles in CFM abundance. Obvious stimulation and inhibition effects on CFM abundance only happened at low levels of total carbon and precipitation, where the tipping points were 6.1 g·kg -1 and 22.38 mm, respectively. The abundance of CFMs in response to nitrogen fertilizer changed from positive to negative (tipping point at 9.45 kg ha -1 ·y -1 ). Approximately 46% of CFM abundance decline happened in cropland at 2100. Our work presents the distribution of carbon-fixing microorganisms on a global scale and then points out the sensitive areas with significant abundance changes. The previously described information will provide references for future soil quality prediction and policy decision-making., Competing Interests: The authors declare no competing financial interests., (© 2023 The Author(s).)

An ordinary least squares (OLS) analysis of the relationship between chlorophyll a (chl a) concentrations and photosynthetic rates at depths of 5 and 25 m at Station ALOHA produced a slope that was only 28% of the mean productivity index at those depths and an intercept at zero chl a that equaled 70% of the mean photosynthetic rate. OLS regression lines are known to produce a slope and intercept that are biased estimates of the true slope and intercept when the explanatory variable, X, is uncontrolled, but in this case the measurement errors and natural variability of the chl a concentrations were much too small to explain the apparent bias. The bias was traceable to the fact that the photosynthetic rates were determined by more than one explanatory variable, a source of variability that is typically overlooked in discussions of OLS bias. Modeling the photosynthetic rates as a function of the product of chl a and surface irradiance produced a much more accurate and realistic description of the data, but the OLS continued to be biased, presumably because the photosynthetic rates were functions of factors in addition to chl a and surface irradiance (e.g., temperature, macronutrients, trace metals, and vitamins). The results underscore the need to recognize that the absence of bias in an OLS when X is not controlled implies that all scatter in the data about the OLS is due to errors in the dependent variable, an unlikely scenario. In most cases, resolution of the bias problem will require identification of the explanatory variables in addition to X that determine the dependent variable.

The application of the eddy covariance flux method to measure fluxes of trace gas and energy between ecosystems and the atmosphere has exploded over the past 25 years. This opinion paper provides a perspective on the contributions and future opportunities of the eddy covariance method. First, the paper discusses the pros and cons of this method relative to other methods used to measure the exchange of trace gases between ecosystems and the atmosphere. Second, it discusses how the use of eddy covariance method has grown and evolved. Today, more than 400 flux measurement sites are operating world-wide and the duration of the time series exceed a decade at dozens of sites. Networks of tower sites now enable scientists to ask scientific questions related to climatic and ecological gradients, disturbance, changes in land use, and management. The paper ends with discussions on where the field of flux measurement is heading. Topics discussed include role of open access data sharing and data mining, in this new era of big data, and opportunities new sensors that measure a variety of trace gases, like volatile organic carbon compounds, methane and nitrous oxide, and aerosols, may yield. [ABSTRACT FROM AUTHOR]

Forests are expected to expand into alpine areas because of climate warming, causing land-cover change and fragmentation of alpine habitats. However, this expansion will only occur if the present upper treeline is limited by low-growing season temperatures that reduce plant growth. This temperature limitation has not been quantified at a landscape scale. Here, we show that temperature alone cannot realistically explain high-elevation tree cover over a >100-km2 area in the Canadian Rockies and that geologic/geomorphic processes are fundamental to understanding the heterogeneous landscape distribution of trees. Furthermore, upslope tree advance in a warmer scenario will be severely limited by availability of sites with adequate geomorphic/topographic characteristics. Our results imply that landscape-to-regional scale projections of warming-induced, high-elevation forest advance into alpine areas should not be based solely on temperature-sensitive, site-specific upper-treeline studies but also on geomorphic processes that control tree occurrence at long (centuries/millennia) timescales. [ABSTRACT FROM AUTHOR]

The eastern Australian rainforests have experienced several cycles of range contraction and expansion since the late Miocene that are closely correlated with global glaciation events. Together with ongoing aridification of the continent, this has resulted in current distributions of native closed forest that are highly fragmented along the east coast. Several closed forest endemic taxa exhibit patterns of population genetic structure that are congruent with historical isolation of populations in discrete refugia and reflect evolutionary histories dramatically affected by vicariance. Currently, limited data are available regarding the impact of these past climatic fluctuations on freshwater invertebrate taxa. The non-biting midge species Echinocladius martini Cranston is distributed along the east coast and inhabits predominantly montane streams in closed forest habitat. Phylogeographic structure in E. martini was resolved here at a continental scale by incorporating data from a previous pilot study and expanding the sampling design to encompass populations in the Wet Tropics of north-eastern Queensland, south-east Queensland, New South Wales and Victoria. Patterns of phylogeographic structure revealed several deeply divergent mitochondrial lineages from central and south-eastern Australia that were previously unrecognised and were geographically endemic to closed forest refugia. Estimated divergence times were congruent with late Miocene onset of rainforest contractions across the east coast of Australia. This suggested that dispersal and gene flow among E. martini populations isolated in refugia has been highly restricted historically. Moreover, these data imply, in contrast to existing preconceptions about freshwater invertebrates, that this taxon may be acutely susceptible to habitat fragmentation. [ABSTRACT FROM AUTHOR]

Groundwater represents almost half of the drinking water worldwide and more than one third of water used for irrigation. Agro-industrial activities affect water resources in several manners; one of the most important is leaching of agrochemical residues. This research identifies the major contributors of changes in groundwater quality comparing two contrasting land uses in a karstic area of the Yucatan peninsula as case study. Using a multiple approach, we assess the impact of land use with physicochemical data, multivariate analyses, hydrogeochemistry and nitrate isotopic composition. We confirmed that agricultural land use has a greater impact on groundwater quality, observed in higher concentration of nitrates, ammonium, potassium and electrical conductivity. Seasonality has an influence on phosphates and the chemical composition of the groundwater, increasing the concentration of dissolved substances in the rainy season. There was a clear effect of manure application in the agricultural zone and the nitrate isotopic composition of groundwater points toward recharge in certain areas. We consider that seasonality and land use effects are intertwined and sometimes difficult to separate, likely because of land use intensity and hydrogeochemical process at a local scale. Finally, we observed poor groundwater quality in the agricultural area during the wet season; thus, it is desirable to maintain non-agricultural areas that provide groundwater of appropriate quality., (© 2020 The Author(s).)

Open Access (OA) describes the free, unrestricted access to and re-use of research articles. Recently, a new wave of interest, debate, and practice surrounding OA publishing has emerged. In this paper, we provide a simple overview of the trends in OA practice in the broad field of geochemistry. Characteristics of the approach such as whether or not an article processing charge (APC) exists, what embargo periods or restrictions on self-archiving' policies are in place, and whether or not the sharing of preprints is permitted are described. The majority of journals have self-archiving policies that allow authors to share their peer reviewed work via green OA without charge. There is no clear relationship between journal impact and APC. The journals with the highest APC are typically those of the major commercial publishers, rather than the geochemistry community themselves. The rise in OA publishing has potential impacts on the profiles of researchers and tends to devolve costs from organizations to individuals. Until the geochemistry community makes the decision to move away from journal-based evaluation criteria, it is likely that such high costs will continue to impose financial inequities upon research community. However, geochemists could more widely choose legal self-archiving as an equitable and sustainable way to disseminate their research., (© 2020 Published by Elsevier Ltd.)

The subsurface represents a largely unexplored frontier in microbiology. Here, coal seams present something of an oasis for microbial life, providing moisture, warmth, and abundant fossilized organic material. Microbes in coal seams are thought to syntrophically mobilize fossilized carbon from the geosphere to the biosphere. Despite the environmental and economic importance of this process, little is known about the microbial ecology of coal seams. In the current study, ecological succession and spatial niche partitioning are explored in three coal seam microbial communities. Scanning electron microscopic visualization and 16S rRNA sequencing track changes in microbial communities over time, revealing distinct attached and planktonic communities displaying patterns of ecological succession. Attachment to the coal surface is biofilm mediated on Surat coal, whereas microbes on Sydney and Gunnedah coal show different attachment processes. This study demonstrates that coal seam microbial communities undergo spatial niche partitioning during periods of succession as microbes colonize coal environments., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Elucidating the effect of harsh environments on the activities of microorganisms is important in revealing how microbes withstand unfavorable conditions or evolve mechanisms to counteract those effects, many of which involve electron transfer phenomena. Here we show that the non-acidophilic and non-thermophilic Bacillus subtilis is able to maintain activity after being subjected to extreme temperatures (100°C for up to 8 h) and acidic environments (pH = 1.50 for over 2 years). In the process, our results suggest that B. subtilis utilizes an extracellular electron transfer as an electron communication pathway between B. subtilis and the environment that involves the cofactor nicotinamide adenine dinucleotide as an essential participant to maintain viability. Elucidation of the capability of the non-acidophilic and non-thermophilic strain to maintain viability under these extreme conditions could aid in understanding the cell responses to different environments from the perspective of energy conservation pathways., (Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.)

Sea spray aerosols (SSA), have a profound effect on the climate; however, the contribution of oceanic microbial activity to SSA is not fully established. We assessed aerosolization of the calcite units (coccoliths) that compose the exoskeleton of the cosmopolitan bloom-forming coccolithophore, Emiliania huxleyi. Airborne coccolith emission occurs in steady-state conditions and increases by an order of magnitude during E. huxleyi infection by E. huxleyi virus (EhV). Airborne to seawater coccolith ratio is 1:10 8 , providing estimation of airborne concentrations from seawater concentrations. The coccoliths' unique aerodynamic structure yields a characteristic settling velocity of ∼0.01 cm s -1 , ∼25 times slower than average sea salt particles, resulting in coccolith fraction enrichment in the air. The calculated enrichment was established experimentally, indicating that coccoliths may be key contributors to coarse mode SSA surface area, comparable with sea salt aerosols. This study suggests a coupling between key oceanic microbial interactions and fundamental atmospheric processes like SSA formation., (Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.)