Metagenomic and -transcriptomic analyses of microbial nitrogen transformation potential, and gene expression in Swiss lake sediments.

The global nitrogen (N) cycle has been strongly altered by anthropogenic activities, including increased input of bioavailable N into aquatic ecosystems. Freshwater sediments are hotspots with regards to the turnover and elimination of fixed N, yet the environmental controls on the microbial pathways involved in benthic N removal are not fully understood. Here, we analyze the abundance and expression of microbial genes involved in N transformations using metagenomics and -transcriptomics across sediments of 12 Swiss lakes that differ in sedimentation rates and trophic regimes.

Tidal control on aerobic methane oxidation and mitigation of methane emissions from coastal mangrove sediments.

Mangrove forests represent important sources of methane, partly thwarting their ecosystem function as an efficient atmospheric carbon dioxide sink. Many studies have focused on the spatial and temporal variability of methane emissions from mangrove ecosystems, yet little is known about the microbial and physical controls on the release of biogenic methane from tidally influenced mangrove sediments. Here, we show that aerobic methane oxidation is a key microbial process that effectively reduces methane emissions from mangrove sediments.

Solid phase speciation controls copper mobilisation from marine sediments by methanobactin.

Although marine environments represent huge reservoirs of the potent greenhouse gas methane, they currently contribute little to global net methane emissions. Most of the methane is oxidized by methanotrophs, minimizing escape to the atmosphere. Aerobic methanotrophs oxidize methane mostly via the copper (Cu)-bearing enzyme particulate methane monooxygenase (pMMO).

Manganese reductive dissolution coupled to Sb mobilization in contaminated shooting range soil.

A "redox-stat" R bioreactor was employed to simulate moderately reducing conditions (+ 420 mV) in Sb-contaminated shooting range soils for approximately 3 months, thermodynamically favoring Mn(IV) reduction. The impact of moderately reducing conditions on elemental mobilization (Mn, Sb, Fe) and speciation [Sb(III) versus Sb(V); Fe/Fe] was compared to a control bioreactor R without a fixed redox potential. In both bioreactors, reducing conditions were accompanied by an increase in effluent Sb(V) and Mn(II) concentrations, suggesting that Sb(V) was released through microbial reduction of Mn oxyhydroxide minerals.

Nominally identical microplastic models differ greatly in their particle-cell interactions.

Due to the abundance of microplastics in the environment, research about its possible adverse effects is increasing exponentially. Most studies investigating the effect of microplastics on cells still rely on commercially available polystyrene microspheres. However, the choice of these model microplastic particles can affect the outcome of the studies, as even nominally identical model microplastics may interact differently with cells due to different surface properties such as the surface charge.

Controls and significance of priming effects in lake sediments.

Warming and eutrophication influence carbon (C) processing in sediments, with implications for the global greenhouse-gas budget. Temperature effects on sedimentary C loss are well understood, but the mechanism of change in turnover through priming with labile organic matter (OM) is not. Evaluating changes in the magnitude of priming as a function of warming, eutrophication, and OM stoichiometry, we incubated sediments with C-labeled fresh organic matter (FOM, algal/cyanobacterial) and simulated future climate scenarios (+4°C and +8°C).

Improving the accuracy of δ O and δ O values of O measured by continuous-flow isotope-ratio mass spectrometry with a multipoint isotope-ratio calibration.

Rationale: Stable isotope analysis of O is a valuable tool to identify O -consuming processes in the environment; however, reference materials for O isotope analysis are lacking. Consequently, a one-point calibration with O from ambient air is often applied, which can lead to substantial measurement uncertainties. Our goals were to develop a simple multipoint isotope-ratio calibration approach and to determine measurement errors of δ O and δ O values of O associated with a one-point calibration.

Hydrodynamic regimes modulate nitrogen fixation and the mode of diazotrophy in Lake Tanganyika.

The factors that govern the geographical distribution of nitrogen fixation are fundamental to providing accurate nitrogen budgets in aquatic environments. Model-based insights have demonstrated that regional hydrodynamics strongly impact nitrogen fixation. However, the mechanisms establishing this physical-biological coupling have yet to be constrained in field surveys.

Scaling up benthic primary productivity estimates in a large intertidal estuary using remote sensing.

As two main primary producers in temperate intertidal regions, seagrass and microphytobenthos (MPB) support estuarine ecosystem functions in multiple ways including stabilizing food webs and regulating sediment resuspension among others. Monitoring estuary productivity at large scales can inform ecosystem scale responses to environmental stressors (climate change, pollution and habitat degradation). Here we use a case study to show how Sentinel-2 data can be used to estimate estuary-wide emerged and submerged gross primary productivity (GPP) on intertidal flats by coupling a new machine learning model to map seagrass and unvegetated habitats with literature-derived photosynthesis-irradiance (P - I) relationships.

Growth conditions impact particulate absorption and pigment concentrations in two common bloom forming cyanobacterial species.

Remote sensing using satellite imagery has been promoted as a method to broaden the scale and frequency of cyanobacterial monitoring. This relies on the ability to establish relationships between the reflectance spectra of water bodies and the abundance of cyanobacteria. A challenge to achieving this comes from a limited understanding of the extent to which the optical properties of cyanobacteria vary according to their physiological state and growth environment.

Water column dynamics control nitrite-dependent anaerobic methane oxidation by Candidatus "Methylomirabilis" in stratified lake basins.

We investigated microbial methane oxidation in the water column of two connected but hydrodynamically contrasting basins of Lake Lugano, Switzerland. Both basins accumulate large amounts of methane in the water column below their chemoclines, but methane oxidation efficiently prevents methane from reaching surface waters. Here we show that in the meromictic North Basin water column, a substantial fraction of methane was eliminated through anaerobic methane oxidation (AOM) coupled to nitrite reduction by Candidatus Methylomirabilis.

GLORIA - A globally representative hyperspectral in situ dataset for optical sensing of water quality.

The development of algorithms for remote sensing of water quality (RSWQ) requires a large amount of in situ data to account for the bio-geo-optical diversity of inland and coastal waters. The GLObal Reflectance community dataset for Imaging and optical sensing of Aquatic environments (GLORIA) includes 7,572 curated hyperspectral remote sensing reflectance measurements at 1 nm intervals within the 350 to 900 nm wavelength range. In addition, at least one co-located water quality measurement of chlorophyll a, total suspended solids, absorption by dissolved substances, and Secchi depth, is provided.

Survival time of post and cores after recementation: A 16-year retrospective study with special focus on loss of retention.

Objectives: Numerous studies investigating the survival time of post and cores have found that loss of retention is the most common cause of failure Nevertheless, investigations focusing on decementation, survival after recementation, and the influencing parameters in a large number of patients with long follow-up periods are lacking. Therefore, the aim of this short communication article is the survival analysis of post and cores after recementation and repeated loss of retention.

Materials And Methods: During the observation period (2004-2020), 653 patients received 953 post and cores.

Accuracy and performance of the lattice Boltzmann method with 64-bit, 32-bit, and customized 16-bit number formats.

Fluid dynamics simulations with the lattice Boltzmann method (LBM) are very memory intensive. Alongside reduction in memory footprint, significant performance benefits can be achieved by using FP32 (single) precision compared to FP64 (double) precision, especially on GPUs. Here we evaluate the possibility to use even FP16 and posit16 (half) precision for storing fluid populations, while still carrying arithmetic operations in FP32.

Multiple Groups of Methanotrophic Bacteria Mediate Methane Oxidation in Anoxic Lake Sediments.

Freshwater lakes represent an important source of the potent greenhouse gas methane (CH) to the atmosphere. Methane emissions are regulated to large parts by aerobic (MOx) and anaerobic (AOM) oxidation of methane, which are important CH sinks in lakes. In contrast to marine benthic environments, our knowledge about the modes of AOM and the related methanotrophic microorganisms in anoxic lake sediments is still rudimentary.

Tracing NO formation in full-scale wastewater treatment with natural abundance isotopes indicates control by organic substrate and process settings.

Nitrous oxide (NO) dominates greenhouse gas emissions in wastewater treatment plants (WWTPs). Formation of NO occurs during biological nitrogen removal, involves multiple microbial pathways, and is typically very dynamic. Consequently, NO mitigation strategies require an improved understanding of nitrogen transformation pathways and their modulating controls.

Dataset of five years of and satellite derived chlorophyll concentrations and its spatiotemporal variability in the Rotorua Te Arawa Lakes, New Zealand.

Horizontal patchiness of water quality attributes in lakes substantially influences the ability to accurately determine an average condition of a lake from traditional in situ sampling. Monitoring programmes for lake water quality often rely on water samples from one or few locations but the assumption of representativeness is seldomly tested. Satellite observations can support environmental monitoring by detecting horizontal variability of water quality attributes over entire lakes.

Survival time of post and cores: A 16 year retrospective follow-up study.

Objectives: The retrospective survival study (1995-2004) by Balkenhol et al. [1]. led to changes in the decision-making process for treatment with post and cores (special focus on the covering prosthetic restoration while deciding for treatment with post and cores, high primary friction at the try-in stage for conventional cementation, only indirect fabrication technique, no semi-precious alloy) in our clinic.

Distinct growth stages controlled by the interplay of deterministic and stochastic processes in functional anammox biofilms.

Mainstream anaerobic ammonium oxidation (anammox) represents one of the most promising energy-efficient mechanisms of fixed nitrogen elimination from wastewaters. However, little is known about the exact processes and drivers of microbial community assembly within the complex microbial biofilms that support anammox in engineered ecosystems. Here, we followed anammox biofilm development on fresh carriers in an established 8m mainstream anammox reactor that is exposed to seasonal temperature changes (~25-12°C) and varying NH concentrations (5-25 mg/L).

Nitrogen isotope effects can be used to diagnose N transformations in wastewater anammox systems.

Anaerobic ammonium oxidation (anammox) plays an important role in aquatic systems as a sink of bioavailable nitrogen (N), and in engineered processes by removing ammonium from wastewater. The isotope effects anammox imparts in the N isotope signatures (N/N) of ammonium, nitrite, and nitrate can be used to estimate its role in environmental settings, to describe physiological and ecological variations in the anammox process, and possibly to optimize anammox-based wastewater treatment. We measured the stable N-isotope composition of ammonium, nitrite, and nitrate in wastewater cultivations of anammox bacteria.

Tapping Freshwaters for Methane and Energy.

Energy supply limits development through fuel constraints and climatic effects. Production of renewable energy is a central pillar of sustainability but will need to play an increasingly important role in energy generation in order to mitigate fossil-fuel based greenhouse-gas emissions. Global freshwaters represent a vast reservoir of biomass and biogenic CH.

Puzzling Haze Events in China During the Coronavirus (COVID-19) Shutdown.

It is a puzzle as to why more severe haze formed during the New Year Holiday in 2020 (NYH-20), when China was in an unprecedented state of shutdown to contain the coronavirus (COVID-19) outbreak, than in 2019 (NYH-19). We performed a comprehensive measurement and modeling analysis of the aerosol chemistry and physics at multiple sites in China (mainly in Shanghai) before, during, and after NYH-19 and NYH-20. Much higher secondary aerosol fraction in PM were observed during NYH-20 (73%) than during NYH-19 (59%).