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The high cost of equipment is a significant entry barrier to research for smaller organisations in developing solutions to air pollution problems. Low-cost electrochemical sensors have shown sensitivity at parts-per-billion by volume (ppbV) mixing ratios but are subject to variations due to changing environmental conditions, particularly temperature. We have previously demonstrated that under isothermal/isohume conditions such as those found in kinetic studies, very stable electrochemical responses occur. In this paper, we demonstrate the utility of a low-cost IoT-based sensor system that employs four-electrode electrochemical sensors under isothermal/isohume conditions for studying the kinetics of the atmospheric oxidation of nitrogen oxides. The results suggest that reproducible results for NO and NO2 kinetics can be achieved. The method produced oxidation rates of 7.95 × 103 L2 mol−2 s−1 (±1.3%), for NO and 7.99 × 10−4 s−1 (±2.1%) for NO2. This study suggests that the oxidation kinetics of nitrogen oxides can be assessed with low-cost sensors, which can support a wide range of industrial applications, such as designing biocatalytic coatings for air pollution remediation.

Abstract Mangroves and saltmarshes are biogeochemical hotspots storing carbon in sediments and in the ocean following lateral carbon export (outwelling). Coastal seawater pH is modified by both uptake of anthropogenic carbon dioxide and natural biogeochemical processes, e.g., wetland inputs. Here, we investigate how mangroves and saltmarshes influence coastal carbonate chemistry and quantify the contribution of alkalinity and dissolved inorganic carbon (DIC) outwelling to blue carbon budgets. Observations from 45 mangroves and 16 saltmarshes worldwide revealed that >70% of intertidal wetlands export more DIC than alkalinity, potentially decreasing the pH of coastal waters. Porewater-derived DIC outwelling (81 ± 47 mmol m−2 d−1 in mangroves and 57 ± 104 mmol m−2 d−1 in saltmarshes) was the major term in blue carbon budgets. However, substantial amounts of fixed carbon remain unaccounted for. Concurrently, alkalinity outwelling was similar or higher than sediment carbon burial and is therefore a significant but often overlooked carbon sequestration mechanism.

Abstract The soil in terrestrial and coastal blue carbon ecosystems is an important carbon sink. National carbon inventories require accurate assessments of soil carbon in these ecosystems to aid conservation, preservation, and nature-based climate change mitigation strategies. Here we harmonise measurements from Australia’s terrestrial and blue carbon ecosystems and apply multi-scale machine learning to derive spatially explicit estimates of soil carbon stocks and the environmental drivers of variation. We find that climate and vegetation are the primary drivers of variation at the continental scale, while ecosystem type, terrain, clay content, mineralogy and nutrients drive subregional variations. We estimate that in the top 0–30 cm soil layer, terrestrial ecosystems hold 27.6 Gt (19.6–39.0 Gt), and blue carbon ecosystems 0.35 Gt (0.20–0.62 Gt). Tall open eucalypt and mangrove forests have the largest soil carbon content by area, while eucalypt woodlands and hummock grasslands have the largest total carbon stock due to the vast areas they occupy. Our findings suggest these are essential ecosystems for conservation, preservation, emissions avoidance, and climate change mitigation because of the additional co-benefits they provide.

Inland waters are important sources of greenhouse gases (GHGs) to the atmosphere that may partially offset the terrestrial carbon sink. However, GHG emissions from high altitude saline lakes on the Tibetan Plateau are currently poorly constrained. In this study, we measured methane (CH4) and carbon dioxide (CO2) concentrations and their carbon stable isotope (δ13C), and calculated diffusive water-to-air fluxes from two saline high-altitude lakes, Qinghai Lake and Hala Lake, located in northeast Tibetan Plateau in October 2020. The two lakes were mostly supersaturated in CH4 (89.8%–4623.9% sat) and acted as sources of CH4 to the atmosphere. Conversely, more than 96% investigated area of Qinghai Lake and all investigated area of Hala Lake was a sink of CO2. The average diffusive fluxes of CH4 and CO2 in the surface waters of Qinghai Lake were 34.51 μmol m−2 d−1 and −1.29 mmol m−2 d−1, while diffusive fluxes of CH4 and CO2 in Hala Lake averaged 5.48 μmol m−2 d−1 and −5.24 mmol m−2 d−1, respectively. Salinity (Sal), fluorescent dissolved organic matter (fDOM), temperature (Temp) and dissolved oxygen (DO) are key factors for diffusive CH4 and CO2 flux in Qinghai Lake and Hala Lake. CH4 diffusive fluxes across water–air interface from Qinghai Lake and Hala Lake were found to be significantly lower than other freshwater lakes, likely due to their saline nature. A simple isotope mixing model (Miller–Tans plots) revealed a distinctly different isotopic source values of CO2 and CH4 in Qinghai Lake and Hala Lake. The CH4 production pathway of Qinghai Lake was mainly by the acetate fermentation, while that of Hala Lake was mainly by the CO2 reduction. The results show that the continuous measurement can help capture the spatial variability of GHGs fluxes in saline lakes.

Coastal wetlands are essential for regulating the global carbon budget through soil carbon sequestration and greenhouse gas (GHG – CO2, CH4, and N2O) fluxes. The conversion of coastal wetlands to agricultural land alters these fluxes' magnitude and direction (uptake/release). However, the extent and drivers of change of GHG fluxes are still unknown for many tropical regions. We measured soil GHG fluxes from three natural coastal wetlands – mangroves, salt marsh, and freshwater tidal forests – and two alternative agricultural land uses – sugarcane farming and pastures for cattle grazing (ponded and dry conditions). We assessed variations throughout different climatic conditions (dry–cool, dry–hot, and wet–hot) within 2 years of measurements (2018–2020) in tropical Australia. The wet pasture had by far the highest CH4 emissions with 1231±386 mgm-2d-1, which were 200-fold higher than any other site. Dry pastures and sugarcane were the highest emitters of N2O with 55±9 mgm-2d-1 (wet–hot period) and 11±3 mgm-2d-1 (hot-dry period, coinciding with fertilisation), respectively. Dry pastures were also the highest emitters of CO2 with 20±1 gm-2d-1 (wet–hot period). The three coastal wetlands measured had lower emissions, with salt marsh uptake of -0.55±0.23 and -1.19±0.08 gm-2d-1 of N2O and CO2, respectively, during the dry–hot period. During the sampled period, sugarcane and pastures had higher total cumulative soil GHG emissions (CH4+N2O) of 7142 and 56 124 CO2-eqkgha-1yr-1 compared to coastal wetlands with 144 to 884 CO2-eqkgha-1yr-1 (where CO2-eq is CO2 equivalent). Restoring unproductive sugarcane land or pastures (especially ponded ones) to coastal wetlands could provide significant GHG mitigation.

Hypersaline tidal flats (HTFs) are coastal ecosystems with freshwater deficits often occurring in arid or semi-arid regions near mangrove supratidal zones with no major fluvial contributions. Here, we estimate that organic carbon (OC), total nitrogen (TN) and total phosphorus (TP) were buried at rates averaging 21 (±6), 1.7 (±0.3) and 1.4 (±0.3) gm-2yr-1, respectively, during the previous century in three contrasting HTF systems, one in Brazil (eutrophic) and two in Australia (oligotrophic). Although these rates are lower than those from nearby mangrove, saltmarsh and seagrass systems, the importance of HTFs as sinks for OC, TN and TP may be significant given their extensive coverage. Despite the measured short-term variability between net air–saltpan CO2 influx and emission estimates found during the dry and wet season in the Brazilian HTF, the only site with seasonal CO2 flux measurements, the OC sedimentary profiles over several decades suggest efficient OC burial at all sites. Indeed, the stable isotopes of OC and TN (δ13C and δ15N) along with C:N ratios show that microphytobenthos are the major source of the buried OC in these HTFs. Our findings highlight a previously unquantified carbon as well as a nutrient sink and suggest that coastal HTF ecosystems could be included in the emerging blue carbon framework.

The photosynthesis performed by trees makes them an important sink for atmospheric carbon dioxide, but trees are also sources of the potent greenhouse gas methane. Here the authors find that tree bark in some common lowland species is colonized by methane oxidizing bacteria that can reduce tree methane emissions by ~ 36%.

Earth’s Radiation Budget is partly dictated by the fragile and complex balance between biogenic volatile organic compounds (BVOCs) and greenhouse gases (GHGs), which have the potential to impose cooling or warming once emitted to the atmosphere. Whilst methane (CH4) is strictly associated with global warming due to its solar-radiation absorbing properties, dimethyl sulfide (DMS) is generally considered a cooling gas through the light scattering properties of its atmospheric oxidation products. However, DMS may also partially contribute to the Earth’s warming through a small portion of it being degraded to CH4 in the water column. Coral reefs emit both DMS and CH4 but they have not previously been simultaneously measured. Here, we report DMS and CH4 fluxes as well as aerosol particle counts at Heron Island, southern Great Barrier Reef, during the austral summer of 2016. Sea-to-air DMS and CH4 fluxes were on average 24.9 ± 1.81 and 1.36 ± 0.11 µmol m-2 d-1, whilst intermediate (< 0.5-2.5 um) and large (> 2.5 um) particle number concentrations averaged 5.51 x 106 ± 1.73 x 105 m-3 and 1.15 x 106 ± 4.63 x 104 m-3, respectively. Positive correlations were found between DMS emissions and the abundance of intermediate (R2 = 0.1669, p < 0.001, n = 93) and large (R2 = 0.0869, p = 0.004, n = 93) aerosol particles, suggesting that DMS sea-to-air emissions significantly contribute to the growth of existing particles to the measured size ranges at the Heron Island lagoon. Additionally, a strong positive correlation was found between DMS and CH4 fluxes (R2 = 0.7526, p < 0.00001, n = 93), suggesting that the emission of these volatile compounds from coral reefs is closely linked. The slope of the regression between DMS and CH4 suggests that CH4 emissions at the Heron Island lagoon represent 5% of that of DMS, which is consistent with the average sea-to-air fluxes reported in this study (i.e. 24.9 ± 1.81 µmol m-2 d-1 for DMS and 1.36 ± 0.11 for CH4). These findings provide new insights on the complexity of BVOC and GHG emissions in coral reef systems and their potential role in climate regulation.

A combination of elemental analysis, bulk stable isotope analysis (bulk SIA) and compound-specific stable isotope analysis of amino acids (CSIA-AA) was used to assess and monitor carbon (C), nitrogen (N) and sulfur (S) cycling of a mangrove ecosystem that suffered mass dieback of trees in the Gulf of Carpentaria, Australia in 2015–2016, attributed to an extreme drought event. Three field campaigns were conducted 8, 20 and 32 months after the event over a period from 2016 to 2018 to obtain biological time-series data. Invertebrates and associated organic matter including mangroves and sediments from the impacted ecosystem showed enrichment in 13C, 15N and 34S relative to those from an adjacent unimpacted reference ecosystem, likely indicating lower mangrove carbon fixation, lower nitrogen fixation and lower sulfate reduction in the impacted ecosystem. For example, invertebrates representing the feeding types of grazing, leaf feeding and algae feeding were more 13C enriched at the impacted site, by 1.7 ‰–4.1 ‰, and these differences did not change over the period from 2016 to 2018. The CSIA-AA data indicated widespread 13C enrichment across five essential amino acids and all groups sampled (except filter feeders) within the impacted site. The seedling density increased from 0.2 m−2 in 2016 to 7.1 m−2 in 2018 in the impacted forest, suggesting recovery of the vegetation. Recovery of CNS cycling, however, was not evident even after 32 months, suggesting a biogeochemical legacy of the mortality event. Continued monitoring of the post-dieback forest is required to predict the long-term trajectory of ecosystem recovery. This study shows that time-series SIA can track biogeochemical changes over time and evaluate recovery of an impacted ecosystem from an extreme event.

The path to publication is often long, emotional, and bewildering. We share key insights from our experience as authors, educators, and members of the editorial board with The Canadian Journal for the Scholarship of Teaching and Learning that we hope will help authors better understand and navigate the path to publication. In writing a compelling story, we suggest that it is necessary to join a conversation with self, the scholarly community, and the journal. We unpack each of these dimensions and offer considerations on how to craft a powerful manuscript that could ultimately get published. Le chemin qui mène à la publication est souvent long, émotionnel et déconcertant. Nous partageons des idées clés basées sur notre expérience en tant qu’auteurs, éducateurs et membres de l’équipe de rédaction de La revue canadienne sur l’avancement des connaissances en enseignement et en apprentissage. Nous espérons qu’elles aideront les auteurs à mieux comprendre et à parcourir avec succès le chemin menant à la publication. Nous suggérons que pour rédiger un récit captivant, il est nécessaire de se joindre à une conversation avec soi-même, avec la communauté des chercheurs et avec la revue. Nous déballons chacune de ces dimensions et offrons des considérations sur la manière de créer un manuscrit puissant qui pourrait être publié.

A massive mangrove dieback event occurred in 2015–2016 along ∼1000 km of pristine coastline in the Gulf of Carpentaria, Australia. Here, we use sediment and wood chronologies to gain insights into geochemical and climatic changes related to this dieback. The unique combination of low rainfall and low sea level observed during the dieback event had been unprecedented in the preceding 3 decades. A combination of iron (Fe) chronologies in wood and sediment, wood density and estimates of mangrove water use efficiency all imply lower water availability within the dead mangrove forest. Wood and sediment chronologies suggest a rapid, large mobilization of sedimentary Fe, which is consistent with redox transitions promoted by changes in soil moisture content. Elemental analysis of wood cross sections revealed a 30- to 90-fold increase in Fe concentrations in dead mangroves just prior to their mortality. Mangrove wood uptake of Fe during the dieback is consistent with large apparent losses of Fe from sediments, which potentially caused an outwelling of Fe to the ocean. Although Fe toxicity may also have played a role in the dieback, this possibility requires further study. We suggest that differences in wood and sedimentary Fe between living and dead forest areas reflect sediment redox transitions that are, in turn, associated with regional variability in groundwater flows. Overall, our observations provide multiple lines of evidence that the forest dieback was driven by low water availability coinciding with a strong El Niño–Southern Oscillation (ENSO) event and was associated with climate change.

Between late 2015 and early 2016, more than 7,000 ha of mangrove forest died along the coastline of the Gulf of Carpentaria, in northern Australia. This massive die-off was preceded by a strong 2015/2016 El Niño event, resulting in lower precipitation, a drop in sea level and higher than average temperatures in northern Australia. In this study, we investigated the role of hydraulic failure in the mortality and recovery of the dominant species, Avicennia marina, 2 years after the mortality event. We measured predawn water potential (Ψpd) and percent loss of stem hydraulic conductivity (PLC) in surviving individuals across a gradient of impact. We also assessed the vulnerability to drought-induced embolism (Ψ50) for the species. Areas with severe canopy dieback had higher native PLC (39%) than minimally impacted areas (6%), suggesting that hydraulic recovery was ongoing. The high resistance of A. marina to water-stress-induced embolism (Ψ50 = −9.6 MPa), indicates that severe water stress (Ψpd < −10 MPa) would have been required to cause mortality in this species. Our data indicate that the natural gradient of water-stress enhanced the impact of El Niño, leading to hydraulic failure and mortality in A. marina growing on severely impacted (SI) zones. It is likely that lowered sea levels and less frequent inundation by seawater, combined with lower inputs of fresh water, high evaporative demand and high temperatures, led to the development of hyper-salinity and extreme water stress during the 2015/16 summer.

High equipment cost is a significant entry barrier to research for small organizations in developing solutions to air pollution problems. Low-cost electrochemical sensors show sensitivity at parts-per-billion by volume mixing ratios but are subject to variation due to changing environmental conditions, in particular temperature. In this study, we demonstrate a low-cost Internet of Things (IoT)-based sensor system for nitric oxide analysis. The sensor system used a four-electrode electrochemical sensor exposed to a series of isothermal/isohume conditions. When deployed under these conditions, stable baseline responses were achieved, in contrast to ambient air conditions where temperature and humidity conditions may be variable. The interrelationship between working and auxiliary electrodes was linear within an environmental envelope of 20–40 °C and 30–80% relative humidity, with correlation coefficients from 0.9980 to 0.9999 when measured under isothermal/isohume conditions. These data enabled the determination of surface functions that describe the working to auxiliary electrode offsets and calibration curve gradients and intercepts. The linear and reproducible nature of individual calibration curves for stepwise nitric oxide (NO) additions under isothermal/isohume environments suggests the suitability of these sensors for applications aside from their role in air quality monitoring. Such applications would include nitric oxide kinetic studies for atmospheric applications or measurement of the potential biocatalytic activity of nitric oxide consuming enzymes in biocatalytic coatings, both of which currently employ high-capital-cost chemiluminescence detectors.

Policies aiming to preserve vegetated coastal ecosystems (VCE) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here the authors assessed organic carbon storage in VCE across Australian and the potential annual CO2 emission benefits of VCE conservation and find that Australia contributes substantially the carbon stored in VCE globally.

Although wetlands represent the largest natural source of atmospheric CH4, large uncertainties remain regarding the global wetland CH4 flux. Wetland hydrological oscillations contribute to this uncertainty, dramatically altering wetland area, water table height, soil redox potentials, and CH4 emissions. This study compares both terrestrial and aquatic CH4 fluxes in permanent and seasonal remediated freshwater wetlands in subtropical Australia over two field campaigns, representing differing hydrological and climatic conditions. We account for aquatic CH4 diffusion and ebullition rates and plant-mediated CH4 fluxes from three distinct vegetation communities, thereby examining diel and intra-habitat variability. CH4 emission rates were related to underlying sediment geochemistry. For example, distinct negative relationships between CH4 fluxes and both Fe(III) and SO42- were observed. Where sediment Fe(III) and SO42- were depleted, distinct positive trends occurred between CH4 emissions and Fe(II) ∕ acid volatile sulfur (AVS). Significantly higher CH4 emissions (p CH4 flux. The highest CH4 fluxes were consistently emitted from the permanent wetland (1.5 to 10.5 mmol m−2 d−1), followed by the Phragmites australis community within the seasonal wetland (0.8 to 2.3 mmol m−2 d−1), whilst the lowest CH4 fluxes came from a region of forested Juncus spp. (−0.01 to 0.1 mmol m−2 d−1), which also corresponded to the highest sedimentary Fe(III) and SO42-. We suggest that wetland remediation strategies should consider geochemical profiles to help to mitigate excessive and unwanted methane emissions, especially during early system remediation periods.

Calcium carbonates (CaCO3) often accumulate in mangrove and seagrass sediments. Here the authors conducted a meta-analysis of inorganic carbon burial rates in mangrove and seagrass sediments and found that CaCO3 burial contributes to Blue Carbon ecosystems’ capacity to offset sea-level rise without undermining the role as CO2 sinks.

Abstract Unstable blood pressure after spinal cord injury (SCI) is not routinely examined but rather predicted by level and completeness of injury (i.e., American Spinal Injury Association Impairment Scale AIS classification). Our aim was to investigate hemodynamic response to a sit‐up test in a large cohort of individuals with chronic SCI to better understand cardiovascular function in this population. Continuous blood pressure and ECG were recorded from individuals with SCI (n = 159) and non‐injured individuals (n = 48). We found orthostatic hypotension occurred within each level and AIS classification (n = 36). Moreover, 45 individuals with chronic SCI experienced a drop in blood pressure that did not meet the criteria for orthostatic hypotension, but was accompanied by dramatic increases in heart rate, reflecting orthostatic intolerance. A cluster analysis of hemodynamic response to a seated position identified eight distinct patterns of interaction between blood pressure and heart rate during orthostatic stress indicating varied autonomic responses. Algorithmic cluster analysis of heart rate and blood pressure is more sensitive to diagnosing orthostatic cardiovascular dysregulation. This indicates blood pressure instability cannot be predicted by level and completeness of SCI, and the consensus statement definition of orthostatic hypotension is insufficient to characterize the variability of blood pressure and heart rate responses during orthostatic stress. Both blood pressure and heart rate responses are needed to characterize autonomic function after SCI.

Study region: The Great Barrier Reef catchment is located adjacent to the world's largest coral reef system, the Great Barrier Reef, in eastern Queensland, Australia. Study focus: This study characterized the geologic and hydrogeologic settings and evaluated the influence of regional faults on groundwater flow. 3D geological models of six regions within the catchment were constructed using drill-log data from >49,000 wells, digital elevation models and surface geological maps. The 3D models were then integrated with potentiometric surface maps and faults data to conceptualize the hydraulic relationships of aquifer units and estimate groundwater development potentials. Potentiometric surfaces and fault orientations were used to conceptualize groundwater flow directions. New hydrological insights for the region: The 3D geological and hydrogeological characterizations revealed previously unknown faults and aquifer units in the study area. The study found that the central regions consisted of fractured and porous-unconfined aquifers, while confined aquifers, which extend to the coast and likely beyond, were also found in the northern and southern most regions. The orientations of the faults trended in NW-SE directions and could form conduits for south-easterly groundwater flow as opposed to the predominate easterly flow in the porous-unconfined and confined aquifers. The 3D models, aquifer connectivities and geometries provided crucial information to determine groundwater development potentials and offer a first step in developing local and regional groundwater flow and contaminant transport models.

Abstract Groundwater is a primary source of dissolved CO2 and CH4 in Amazonian headwaters, yet in higher order rivers, a groundwater/pore‐water source is difficult to constrain due to the high spatial and temporal heterogeneity of pore‐water exchange. Here, we report coupled, high resolution measurements of pCO2, CH4, and 222Rn (a natural pore‐water and groundwater tracer) during receding waters in the three major water types of the Central Amazon Basin: black (Negro River); clear (Tapajós River); white (Madeira River). Considerable spatial heterogeneity was observed in pCO2, CH4, and 222Rn concentrations ranging from 460 μatm to 8030 μatm, 7 nM to 281 nM, and 713 dpm m−3 to 8516 dpm m−3, respectively. The significant correlations between pCO2 and CH4 to 222Rn in the black and clear waters suggests that pore‐water further enhanced CO2 supersaturation by 18–47% and is a driver of CH4 dynamics in these waters.

A new approach to autonomously determine concentrations of dissolved inorganic carbon (DIC) and its carbon stable isotope ratio (δ13C–DIC) at high temporal resolution is presented. The simple method requires no customised design. Instead it uses two commercially available instruments currently used in aquatic carbon research. An inorganic carbon analyser utilising non-dispersive infrared detection (NDIR) is coupled to a Cavity Ring-down Spectrometer (CRDS) to determine DIC and δ13C–DIC based on the liberated CO2 from acidified aliquots of water. Using a small sample volume of 2 mL, the precision and accuracy of the new method was comparable to standard isotope ratio mass spectrometry (IRMS) methods. The system achieved a sampling resolution of 16 min, with a DIC precision of ±1.5 to 2 µmol kg−1 and δ13C–DIC precision of ±0.14 ‰ for concentrations spanning 1000 to 3600 µmol kg−1. Accuracy of 0.1 ± 0.06 ‰ for δ13C–DIC based on DIC concentrations ranging from 2000 to 2230 µmol kg−1 was achieved during a laboratory-based algal bloom experiment. The high precision data that can be autonomously obtained by the system should enable complex carbonate system questions to be explored in aquatic sciences using high-temporal-resolution observations.

Abstract Exchangeable dissolved organic carbon (EDOC) makes up a significant proportion of the oceanic dissolved organic carbon (DOC) pool, yet EDOC sources to the coastal ocean are poorly constrained. We measured the exchange of EDOC and concentrations of EDOC and DOC in mangrove waters over a 26° latitudinal gradient. A clear latitudinal trend was observed, with the highest EDOC concentrations in the tropics. EDOC exports to the coastal ocean were 4.7 ± 1.9 mmol m−2 d−1, equivalent to 11% of DOC exports (42.1 ± 6.7 mmol m−2 d−1). Pore‐water and groundwater exchange were minor sources of EDOC. EDOC concentrations were equal to 13% ± 4% of DOC concentrations. Based on previous global DOC export estimates, and our EDOC : DOC ratios, mangroves outwell 3.1 Tg C yr−1 as EDOC, equivalent to ∼ 60% of the global EDOC flux from the ocean to the atmosphere. However, seasonality of mangrove EDOC cycling requires further research.

In coastal aquatic ecosystems, prokaryotic communities play an important role in regulating the cycling of nutrients and greenhouse gases. In the coastal zone, estuaries are complex and delicately balanced systems containing a multitude of specific ecological niches for resident microbes. Anthropogenic influences (i.e. urban, industrial and agricultural land uses) along the estuarine continuum can invoke physical and biochemical changes that impact these niches. In this study, we investigate the relative abundance of methanogenic archaea and other prokaryotic communities, distributed along a land use gradient in the subtropical Burnett River Estuary, situated within the Great Barrier Reef catchment, Australia. Microbiological assemblages were compared to physicochemical, nutrient and greenhouse gas distributions in both pore and surface water. Pore water samples from within the most urbanised site showed a high relative abundance of methanogenic Euryarchaeota (7.8% of all detected prokaryotes), which coincided with elevated methane concentrations in the water column, ranging from 0.51 to 0.68 μM at the urban and sewage treatment plant (STP) sites, respectively. These sites also featured elevated dissolved organic carbon (DOC) concentrations (0.66 to 1.16 mM), potentially fuelling methanogenesis. At the upstream freshwater site, both methane and DOC concentrations were considerably higher (2.68 μM and 1.8 mM respectively) than at the estuarine sites (0.02 to 0.66 μM and 0.39 to 1.16 mM respectively) and corresponded to the highest relative abundance of methanotrophic bacteria. The proportion of sulfate reducing bacteria in the prokaryotic community was elevated within the urban and STP sites (relative abundances of 8.0%- 10.5%), consistent with electron acceptors with higher redox potentials (e.g. O2, NO3-) being scarce. Overall, this study showed that ecological niches in anthropogenically altered environments appear to give an advantage to specialized prokaryotes invoking a potential change in the thermodynamic landscape of the ecosystem and in turn facilitating the generation of methane-a potent greenhouse gas.

Abstract Through the microbial breakdown of organic matter and production of greenhouse gases (GHGs), small agricultural dams or ponds have recently been shown to make a relatively large contribution to freshwater ecosystem carbon cycling. However, current estimates of their total carbon dioxide‐equivalent (CO2‐e) emissions lack inclusion of both seasonal and diel fluctuations. In addition, the atmospheric emissions of nitrous oxide from these often eutrophic systems have yet to be established. Here, we quantified the diffusive winter emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from 12 small agricultural dams within southeast Australia over a 24‐h period. The winter CO2‐e emissions of small agricultural water bodies were ~92% lower than previous summer estimates, at 1.02 g·m−2·d−1, while N2O contributed just 3.2% of this total. We also show that diel cycles do not significantly affect winter CO2, CH4, or N2O emission rates, and we discuss the likely carbon sources to these systems, through analyses of stable carbon isotopes (δ13C). The results from this study fill key gaps in our knowledge of agricultural dam GHG production and global atmospheric emissions, aiding their inclusion into future GHG budgets.

We all fail. We also like to look good and avoid looking bad. So, even though we know that taking risks and trying new approaches are important for enhancing our teaching and students’ learning (Strean, 2017), we rarely talk about our failures. Our claim in this paper is that our insecurities create a substantial barrier to improving and enriching our teaching practices. If we do not find time to take big risks, and then to explore and critically reflect on failures that result sometimes from those risks, we lose out on the chance to become better teachers; more fundamentally, we deprive our students of the chance to have extraordinary opportunities to learn. Nous connaissons tous des échecs. Or, nous voulons projeter une image positive de nous-mêmes. Ainsi, même si nous savons qu’il est important de prendre des risques et d’essayer de nouvelles approches pour améliorer notre enseignement ainsi que l’apprentissage de nos étudiants (Strean, 2017), il est rare que nous parlions de nos échecs. Dans cet article, nous avançons l’idée suivante : notre manque d’assurance constitue un obstacle considérable à l’amélioration et à l’enrichissement de nos pratiques d’enseignement. Si nous ne nous donnons pas du temps pour prendre des risques importants, puis pour réfléchir de manière critique sur les échecs qui découlent parfois de cette prise de risque, nous laissons passer une occasion de nous améliorer en tant qu’enseignants. Qui plus est, nous privons ainsi nos étudiants d’occasions d’apprentissage exceptionnelles.

The aim of this study is to prepare a new ester prodrug. used for this purpose ascorbic acid vitamin C and indomethacin by esterification reaction, and partial purification of the AST from blood serum with diabetes type II, and we following steps: 1-preparation of indomethacin chloride by reaction of indomethacin with thionyl chloride.esterification reaction of the hydroxy group in vitamin C with Indomethacin chloride to produce ester indomethacin. And Identification of Structural formula using spectroscopic methods (FTIR(. 2-measuring the AST activity in the blood serum of people with diabetes and blood serum of healthy people. The study included 35 patients serum sample for Type II diabetes and (25) of the serum sample healthy. The control group was observed high level of probability (p

Surface dissolved dimethylsulfide (DMS) and depth-integrated dimethylsulfoniopropionate (DMSP) measurements were made from March to April 2004 during the SOLAS Air–Sea Gas Exchange Experiment (SAGE), a multiple iron enrichment experiment in subantarctic waters SE of New Zealand. During the first two iron enrichments, chl a and DMS production were constrained, but during the third enrichment, large pulses of DMS occurred in the fertilised IN patch, compared with the unfertilised OUT patch. During the third and fourth iron infusions, total chl a concentrations doubled from 0.52 to 1.02 µg/L. Hapto8s and prasinophytes accounted for 50%, and 20%, respectively, of total chl a. The large pulses of DMS during the third iron enrichment occurred during high dissolved DMSP concentrations and wind strength; changes in dinoflagellate, haptophyte, and cyanobacteria biomass; and increased microzooplankton grazing that exerted a top down control on phytoplankton production. A further fourth iron enrichment did cause surface waters to increase in DMS, but the effect was not as great as that recorded in the third enrichment. Differences in the biological response between SAGE and several other iron enrichment experiments were concluded to reflect microzooplankton grazing activities and the microbial loop dominance, resulting from mixing of the MLD during storm activity and high winds during iron enrichment.