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This study has been acomblished between December 2016 and September 2017 which included 70 patients with chronic renal failure who attended at Al-yarmuke teaching hospital in Baghdad with25 healthy individual as control. The research aims to study the effect of hypertension, diabetes and smoking on the levels of some biochemical parameters of chronic renal failure patients comparing with healthy control .The results showed a significant increase in the concentrations of urea, creatine, uric acid, cholesterol, Triglycerides(TG), low density lipoproteins (LDL) and Very low density lipoproteins (VLDL), compared to healthy control. The results also showed that hypertension has an effect on the concentration of urea, uric acid, creatinine, cholesterol, Triglycerides (TG), low density lipoproteins (LDL) and Very low density lipoproteins (VLDL), the results indicated that the diabetes has effects on the concentration of urea, creatinine, cholesterol and Triglycerides (TG), High density lipoproteins (HDL), low density lipoproteins( LDL) and Very Low density lipoproteins (VLDL) with no effects on the concentration of uric acid. There was an effect of smoking on The concentrations of cholesterol and the Triglycerides(TG), low Density Lipoproteins( LDL), Very Low density Lipoproteins (VLDL), urea, uric acid, and creatinine .The gender has no effect on the concentration of all measured parameters except on TG concentration.

Mangrove soil carbon stocks are known to decrease following forest loss due to respiration and enhanced soil CO2 emissions. However, changes in carbon outwelling to the coastal ocean due to mangrove forest disturbance have not been considered. In December 2015, an extremely large mangrove dieback event (∼7000 hectares, spanning 1000 km of coastline) occurred in the Gulf of Carpentaria, Australia. To assess the effect this dieback event had on carbon outwelling, we used radium isotopes and dissolved carbon measurements (dissolved organic carbon, DOC, dissolved inorganic carbon, DIC, and total alkalinity, TAlk) to estimate cross-shelf carbon transport from living and dead mangrove areas and to calculate the carbon losses from living and dead forest soils via SGD. Radium distributions imply cross shelf eddy diffusivity of 107.5 ± 26.9 and 104.6 ± 23.9 m−2 s−1 from dead and living areas and radium water ages reveal that mangrove carbon reaches 10 km offshore within 7 days. Outwelling rates from living and dead areas were explained by soil carbon losses via SGD. This study suggests a decrease in carbon outwelling to the ocean from dead forest areas compares to living areas by 0–12% for DOC, 50–52% for DIC and by 37–51% for TAlk ∼8 months after the dieback event occurred. Changes to oceanic carbon outwelling rates following mangrove loss are likely driven by a gradual depletion of carbon stocks from the sediment profile.

Mangroves sequester large amounts of carbon in soils but limited information is available on carbon losses from tropical mangrove systems. Here we quantify carbon outwelling, CO2 emissions and pore-water exchange rates from two nearby (∼2 km apart) tropical mangrove creeks located in different geomorphic settings on the island of Palau, Micronesia during the monsoon storm season. On average, POC and pCO2 were >100% higher and DOC, DIC and TA were 62%, 25%, 16% higher, respectively, from Creek 1 (located within a semi-enclosed bay) than from Creek 2 (located along the coast adjacent to fringing reefs). Both creeks were net exporters of DIC, DOC, POC, TA and emitters of CO2. However, outwelling rates of POC, DIC and DOC and CO2 emissions were 27-fold, 8-fold, 4-fold and 3-fold higher at Creek 1. DIC outwelling (37%) and CO2 emissions (39%) were the major terms contributing to total carbon losses at Creek 1, whilst CO2 emission (61%) was the major contributor at Creek 2. Monsoon storms appeared to explain the organic carbon dynamics whilst tidal pumping appears to drive the inorganic carbon dynamics at both creeks. Our data demonstrates the considerable heterogeneity of mangroves creeks that are in close proximity and subject to similar weather conditions but in differing geomorphological settings.

Indigenous tourism has the ability to foster, promote and preserve Indigenous culture and traditions and is closely in line with Indigenous perspectives. In Canada, Indigenous tourism has been developing at an exponential rate. This paper is a synopsis of a think tank held in Nanaimo, British Columbia at the Sustainable Indigenous Tourism Symposium in April 2017. The purpose of the symposium was to create an interactive forum to facilitate the sharing of knowledge and support community empowerment, cultural expression and economic prosperity within the tourism industry for Indigenous communities in Canada and globally. On the final day of the symposium, a think tank was held to identify key challenges and issues facing the development and competitiveness of sustainable Indigenous tourism in Canada; to share innovations in sustainable Indigenous tourism amongst all stakeholders; and to identify how to support stakeholders in Canada and abroad with the knowledge and tools to develop sustainable Indigenous tourism. The think tank included consultation and collaboration with 82 stakeholders including Indigenous peoples, students, academics, government actors, tour operators and tourism associations. The results of the think tank identified several key themes and the Naut’sa mawt Declaration of the Development of Sustainable Indigenous Tourism was developed from these discussions.

Coastal lagoons are dynamic aquatic systems that are susceptible to eutrophication due to long residence times and high inputs of nutrients. We hypothesise that groundwater-derived nutrients make a significant contribution to primary production, eutrophication and carbon cycling in these systems. Here, we report results from seasonal (pre-bloom, bloom and post bloom), nutrient, pCO2 and 222Rn (a natural groundwater tracer) surveys in a coastal lagoon that frequently experiences macroalgae blooms (Avoca Lagoon, Australia). Groundwater inputs of DIN and DIP deliver the nutrient load equivalent to the entire lagoon inventory in 1.6 to 3.5 days and 1.7 and 6 days respectively, indicating groundwater was a major source of inorganic nutrients to the system. Lagoon pCO2 displayed significant spatial and temporal variability, with the average pCO2 shifting from 1717 μatm during pre-bloom, to 137 μatm during the bloom and 3056 μatm post bloom. Radon-222 displayed a significant positive relationship with dissolved inorganic nitrogen (DIN) and pCO2 during the pre-bloom period. This suggests a hydrological dominance of surface water DIN and pCO2 during the pre-bloom period. During the bloom period, DIN displayed a positive relationship with pCO2 and negative relationship with dissolved oxygen, indicating a strong biological control over the nutrient pool. Phosphate did not appear to be controlled by either groundwater inputs, or ecosystem metabolism throughout the study. While groundwater discharge stimulated primary production through nutrient inputs (thus reducing surface water CO2), it also directly delivered significant quantities of CO2 to surface waters. The net effect of groundwater inputs of nutrients and dissolved carbon into the lagoon was a stimulation of CO2 fluxes to the atmosphere.

This paper presents the first aquatic CO2 and CH4 flux estimates from a macro-tidal mangrove creek located in the 0–5° latitude band, where ∼30% of the world’s mangroves occur. High resolution dissolved CO2, CH4 and 222Rn (a natural pore-water tracer) concentrations were measured over a spring-neap tidal cycle from a mangrove tidal creek located in North Brazil (∼0.8°S). Surface water pCO2, CH4 and 222Rn ranged from 592 to 15,361 μatm, 58 to 1469 nM, and 585 to 16,583 dpm m−3 with considerable temporal variability observed semi diurnally (i.e. hourly) and over the spring-neap cycle (i.e. weekly). Tidally-driven pore-water exchange (tidal pumping) drove surface water pCO2 and CH4, leading to high concentrations at low-tide (semi-diurnal variability). Higher pCO2 and CH4 were also observed after the inundation of the upper inter-tidal flat, with peak values coinciding with the “first flush” of aged pore-waters. We hypothesise that additional pore-water exchanges occur during forest inundation in macro-tidal mangrove systems, controlling mangrove creek water pCO2 and CH4 over spring-neap cycles. Estimated CO2 and CH4 water-atmosphere fluxes were 174 ± 129 mmol m−2 d−1 and 855 ± 406 μmol m−2 d−1, respectively. These emissions are amongst the highest reported for mangrove systems worldwide and suggests that the most recent global estimates based mostly on data from higher latitudes may have underestimated the role of mangroves in greenhouse gas emissions.

Rivers and streams play a central role in global carbon budget, but our knowledge is limited on the magnitude and extent of urbanization influence on riverine methane (CH

Beef cattle ranching and farming is a major agricultural industry in the U.S. that manages an estimated 147 million ha of private land and uses approximately 92% of forage authorized for grazing on federal rangelands. Rangelands, as working landscapes, sustain beef cattle ranching while providing habitat for wildlife, recreation and open space amenities, as well as spiritual and cultural values that define a way of life. Historically, discussions regarding the economics of beef cattle ranching have focused primarily on the value of beef production but have more recently expanded to consider related ecosystem services. A systematic search of peer-reviewed literature published between 1998 to 2018, found 154 articles that considered ecosystem services from rangelands/grasslands. Of these, only two articles (1%) provided an in-depth economic valuation (monetary measure) of ecosystem services in the U.S. To fill this knowledge gap, we primarily used publicly available data to conduct an economic valuation of major ecosystem services associated with beef cattle production in the U.S. at both the national and state-level. We find that over 186 million ha were actively grazed by beef cattle ranches and farms in the U.S. in 2017. We estimate the economic value of this land use to be $17.5 billion for wildlife recreation, $3.8 billion for forage production, and $3.2 billion for other ecosystem services related to the conservation of biodiversity—a combined total of $24.5 billion. Ecosystem services from federal rangelands in 16 western states accounted for 35% of the total value. Ecosystem services per beef cow and per kilogram of retail beef were estimated to be $1,043.35 and $2.74, respectively. More studies like these are needed to inform decision-makers at the industry, land management, and federal levels to ensure the conservation, improvement, and restoration of these ecosystem services are considered in future management and research efforts.

Tidal coastal wetlands are significant to the global carbon budgets through carbon sequestration and greenhouse gas (GHG; CO2, CH4 and N2O) emissions. The conversion of tidal coastal wetlands to agriculture land alters soil processes changing GHG emissions. The GHG emissions associated with land-use change are important for restoration strategies that rely upon financial incentives such as carbon credits. We measured GHG fluxes from mangroves, saltmarsh and freshwater tidal forest and their alternative agricultural lands including sugarcane and ponded pastures. We investigated seasonal variations between June 2018 and February 2020 in tropical. Australia. The wet ponded pasture had by far the highest CH4 emissions with 1,231 ± 386 mg m−2 d−1, which were 200-fold higher than any other land use. Agricultural lands were the most significant sources of N2O emissions with 55 ± 9 mg m−2 d−1 from dry ponded pasture (wet-hot period) and 11 ± 3 mg m−2 d−1 from sugar cane (hot-dry period), coinciding with fertilisation. The N2O fluxes from the tidal coastal wetlands ranged between −0.55 ± 0.23 and 2.76 ± 0.45 mg m−2 d−1 throughout the study period. The highest CO2 fluxes of 20 ± 1 g m−2 d−1 were from the dry ponded pasture during the wet-hot period, while the saltmarsh had the lowest CO2 fluxes having an uptake of −1.19 ± 0.08 g m−2 d−1 in the dry-hot period. Overall, agricultural lands had significantly higher total cumulative GHG emissions (CH4 + N2O) of 7142 to 56,124 CO2-eq kg ha−1 y−1 compared to those of any type of tidal coastal wetlands, which ranged between 144 and 884 CO2-eq kg ha−1 y−1. Converting agricultural land, particularly wet ponded pasture, to tidal coastal wetlands could provide large GHG mitigation gains and potential financial incentives.

Knowledge regarding processes, pathways and mechanisms that may moderate methane (CH4) sink/source behaviour along the sediment - tree stem - atmosphere continuum remains incomplete. Here, we applied stable isotope analysis (δ13C-CH4) to gain insights into axial CH4 transport and oxidation in two common and globally distributed subtropical lowland forest species (Melaleuca quinquenervia and Casuarina glauca). We found consistent trends in CH4 flux (decreasing with height) and δ13C-CH4 enrichment (increasing with height) in relation to stem height from the ground. The average lower tree stem (0-40 cm) δ13C-CH4 of M. quinquenervia and C. glauca flooded forests (-53.96 ‰ and -65.89 ‰) were similar to adjacent flooded sediment CH4 ebullition (-52.87 ‰ and -62.98 ‰), suggesting that CH4 is produced mainly via sedimentary sources. Upper stems (81-200 cm) displayed distinct δ13C-CH4 enrichment (M. quinquenervia -44.6 ‰ and C. glauca -46.5 ‰ respectively) compared to lower stems. Coupled 3D photogrammetry and novel 3D measurements on M. quinquenervia revealed that distinct hotspots of CH4 flux and isotopic fractionation were likely due to bark anomalies where preferential pathways of gas efflux were likely enhanced. By applying a fractionation factor (derived from previous lab based tree stem bark experiments), diel experiments revealed greater δ13C-CH4 enrichment and higher oxidation rates in the afternoon relative to the morning. Overall, we estimate CH4 oxidation rates between the lower to upper stems across both species ranged from 1 to 69 % (average 33.1 ± 3.4 %), representing a substantial tree-associated CH4 sink occurring during axial transport.

BackgroundFVC declines gradually with aging. The loss of lung function in patients with progressive SSc-ILD mimics an accelerated ageing process.ObjectivesUsing reference equations, we estimated the “effective lung age” of subjects in the SENSCIS trial (i.e. the age of healthy individuals with the same FVC) and compared these estimates to their real age.MethodsThe SENSCIS trial enrolled subjects with SSc-ILD with first non-Raynaud symptom within the prior ≤7 years, extent of fibrotic ILD on HRCT ≥10%, FVC ≥40% predicted, DLco 30–89% predicted. Evidence of recent decline in FVC was not an inclusion criterion. Subjects were randomised to receive nintedanib or placebo. Using reference equations published by the European Respiratory Society Global Lung Function Initiative, based on FVC data from over 70,000 healthy individuals aged 3–95 years from 26 countries, [Quanjer et al. Eur Respir J 2012;40:1324–1343], we estimated the effective lung age of subjects at baseline and at week 52 based on their FVC, sex, ethnicity and height, and compared these effective lung ages with the subjects’ real ages. Three subjects aged ResultsMean time since onset of first non-Raynaud symptom was 3.5 years in both the nintedanib and placebo groups. At baseline, mean (SD) effective lung age was 83.1 (14.4) years in the nintedanib group (n=287) and 82.9 (14.8) years in the placebo group (n=286). In these groups, respectively, the mean (SD) difference between effective lung age and real age was 28.4 (17.7) and 29.3 (18.5) years and the difference was >20 years in 71.4% and 72.4% of subjects. In the nintedanib and placebo groups, respectively, median (Q1, Q3) effective lung age was 88.4 (74.6, 95.0) and 88.5 (74.7, 95.0) years at baseline and 91.0 (75.2, 95.0) and 95.0 (75.9, 95.0) years at week 52.ConclusionAt entry into the SENSCIS trial, subjects with SSc-ILD had an effective lung age that was much higher than their real age. Over 52 weeks, the increase in effective lung age was numerically lower in subjects treated with nintedanib than placebo. These data show that marked loss of lung function that can occur in the few years following onset of SSc-ILD and support a benefit of nintedanib in slowing the progression of SSc-ILD.AcknowledgementsThe SENSCIS trial was funded by Boehringer Ingelheim. Toby M Maher and Oliver Distler were members of the SENSCIS trial Steering Committee.Disclosure of InterestsToby Maher Speakers bureau: Boehringer Ingelheim, Galapagos, Genentech, Consultant of: AstraZeneca, Bayer, Blade Therapeutics, Boehringer Ingelheim, Bristol-Myers Squibb, Galapagos, Galecto, GlaxoSmithKline R&D, IQVIA, Pliant, Respivant, Roche, Theravance and Veracyte, Grant/research support from: AstraZeneca, GlaxoSmithKline, Arnaud Bourdin Speakers bureau: Amgen, AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Novartis, Regeneron, Sanofi, Paid instructor for: Amgen, AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Novartis, Regeneron, Sanofi, Consultant of: Amgen, AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Novartis, Regeneron, Sanofi, Grant/research support from: AstraZeneca and Boehringer Ingelheim, Elizabeth Volkmann Speakers bureau: Boehringer Ingelheim, Consultant of: Boehringer Ingelheim, Grant/research support from: Boehringer Ingelheim, Corbus, Forbius, Horizon, Kadmon, Serena Vettori Consultant of: Boehringer Ingelheim, Jörg H.W. Distler Shareholder of: 4D Science, Speakers bureau: Boehringer Ingelheim, Inventiva, Janssen, and UCB, Consultant of: AbbVie, Active Biotech, Anamar, ARXX, AstraZeneca, Bayer Pharma, Boehringer Ingelheim, Celgene, Galapagos, GlaxoSmithKline, Inventiva, Janssen, Novartis, Pfizer, and UCB, Grant/research support from: Anamar, ARXX, Bristol-Myers Squibb, Bayer Pharma, Boehringer Ingelheim, Cantargia, Celgene, CSL Behring, Galapagos, GlaxoSmithKline, Inventiva, Kiniksa, Sanofi-Aventis, RedX, UCB, Margarida Alves Employee of: Margarida Alves is an employee of Boehringer Ingelheim, Christian Stock Employee of: Christian Stock is an employee of Boehringer Ingelheim, Oliver Distler Speakers bureau: OD has/had relationships with the following companies in the area of potential treatments for systemic sclerosis and its complications in the last three calendar years:Speaker fee: Bayer, Boehringer Ingelheim, Janssen, Medscape, Consultant of: OD has/had relationships with the following companies in the area of potential treatments for systemic sclerosis and its complications in the last three calendar years:Consultancy fee: Abbvie, Acceleron, Alcimed, Amgen, AnaMar, Arxx, AstraZeneca, Baecon, Blade, Bayer, Boehringer Ingelheim, Corbus, CSL Behring, 4P Science, Galapagos, Glenmark, Horizon, Inventiva, Kymera, Lupin, Miltenyi Biotec, Mitsubishi Tanabe, MSD, Novartis, Prometheus, Roivant, Sanofi and TopadurOD has/had relationships with the following companies in the area of potential treatments for arthritides in the last three calendar years:Consultancy fee: Abbvie, Grant/research support from: OD has/had relationships with the following companies in the area of potential treatments for systemic sclerosis and its complications in the last three calendar years:Research Grants: Boehringer Ingelheim, Kymera, Mitsubishi Tanabe

Beef cattle ranching and farming is a major agricultural industry in the United States that manages an estimated 147 million ha of private land and uses approximately 92% of forage authorized for grazing on federal rangelands. Rangelands, as working landscapes, sustain beef cattle ranching while providing habitat for wildlife, recreation, and open space amenities, as well as spiritual and cultural values that define a way of life. Historically, discussions regarding the economics of beef cattle ranching have focused primarily on the value of beef production but have more recently expanded to consider related ecosystem services. A systematic search of peer-reviewed literature published between 1998 and 2018 found 154 articles that considered ecosystem services from rangelands/grasslands. Of these, only two articles (1%) provided an in-depth economic valuation (monetary measure) of ecosystem services in the United States. To fill this knowledge gap, we primarily used publicly available data to conduct an economic valuation of major ecosystem services associated with beef cattle production in the United States at both the national and state levels. We find that over 186 million ha were actively grazed by beef cattle ranches and farms in the United States in 2017. We estimate the economic value of this land use to be $17.5 billion for wildlife recreation, $3.8 billion for forage production, and $3.2 billion for other ecosystem services related to the conservation of biodiversity—a combined total of $24.5 billion. Ecosystem services from federal rangelands in 16 western states accounted for 35% of the total value. Ecosystem services per beef cow and per kilogram of retail beef were estimated to be $1,043.35 and $2.74, respectively. More studies like these are needed to inform decision-makers at the industry, land management, and federal levels to ensure that the conservation, improvement, and restoration of these ecosystem services are considered in future management and research efforts.

Tree stems are an important and unconstrained source of methane, yet it is uncertain whether internal microbial controls (i.e. methanotrophy) within tree bark may reduce methane emissions. Here we demonstrate that unique microbial communities dominated by methane-oxidising bacteria (MOB) dwell within bark of Melaleuca quinquenervia, a common, invasive and globally distributed lowland species. In laboratory incubations, methane-inoculated M. quinquenervia bark mediated methane consumption (up to 96.3 µmol m−2 bark d−1) and reveal distinct isotopic δ13C-CH4 enrichment characteristic of MOB. Molecular analysis indicates unique microbial communities reside within the bark, with MOB primarily from the genus Methylomonas comprising up to 25 % of the total microbial community. Methanotroph abundance was linearly correlated to methane uptake rates (R2 = 0.76, p = 0.006). Finally, field-based methane oxidation inhibition experiments demonstrate that bark-dwelling MOB reduce methane emissions by 36 ± 5 %. These multiple complementary lines of evidence indicate that bark-dwelling MOB represent a potentially significant methane sink, and an important frontier for further research., 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%.

The small-scale spatial variability in dissolved carbon dioxide (CO2) and water-air CO2 flux dynamics were investigated within first-order catchments of the upper Blue Mountains Plateau (New South Wales, Australia). Water samples were collected at 81 locations during winter and summer over two consecutive years across seven aquatic ecosystem types: wetland, impoundment, lake, tributary stream, mainstem, escarpment complex, and urban-aquatic interface. Dissolved [CO2] ranged from 15 to 880 μM (94 to 4760%Sat), and dissolved [O2] from 0 to 350 μM (0 to 101%Sat). CO2 supersaturation was typically highest in wetlands and vegetated impoundments of the upper plateau, and decreased downstream approaching atmospheric equilibrium at the escarpment waterfalls. Gas transfer velocities ranged from 0.18 m d−1 in lentic waters to 292 m d−1 at the bottom of waterfalls due to bubble-mediated transfer. The first- and second-order streams represented only 4.8% of the total open water area yet contributed to 61% of the total water-air CO2 outgassing. The lake, escarpment and mainstem group systems had narrow diel and seasonal CO2 concentration variability, while wetlands and vegetated impoundments had the widest ranges. Our high resolution spatio-temporal sampling was essential to identifying CO2 outgassing hotspots in these geomorphically diverse catchments. Overall, >95% of excess dissolved CO2 traversing the upper Blue Mountains Plateau was outgassed to the atmosphere.

Warming-induced mountain pine beetle (Dendroctonus ponderosae; MPB) outbreaks have caused extensive mortality of whitebark pine (Pinus albicaulis; WBP) throughout the species' range. In the highest mountains where WBP occur, they cross alpine treeline ecotones (ATEs) where growth forms transition from trees to shrub-like krummholz, some of which survived recent MPB outbreaks. This observation motivated the hypothesis that ATEs are refugia for WBP because krummholz growth forms escape MPB attack and have the potential to produce viable seed. To test this hypothesis, we surveyed WBP mortality along transects from the ATE edge (locally highest krummholz WBP) downslope into the forest and, to distinguish if survival mechanisms are unique to ATEs, across other forest ecotones (OFEs) from the edge of WBP occurrence into the forest. We replicated this design at 10 randomly selected sites in the U.S. Northern Rocky Mountains. We also surveyed reproduction in a subset of ATE sites. Mortality was nearly absent in upper ATEs (mean ± SE percent dead across all sites of 0.03% ± 0.03% 0-100 m from the edge and 14.1% ± 1.7% 100-500 m from the edge) but was above 20% along OFEs (21.4 ± 5.2% 0-100 m and 32.4 ± 2.7% 100-500 m from the edge). We observed lower reproduction in upper ATEs (16 ± 9.9 cones/ha and 12.9 ± 5.3 viable seeds/cone 0-100 m from the edge) compared to forests below (317.1 ± 64.4 cones/ha and 32.5 ± 2.5 viable seeds/cone 100-500 m from the edge). Uniquely high WBP survival supports the hypothesis that ATEs serve as refugia because krummholz growth forms escape MPB attack. However, low reproduction suggests ATE refugia function over longer time periods. Beyond our WBP system, we propose that plant populations in marginal environments are candidate refugia if distinct phenotypes result in reduced disturbance impacts.

Enhanced Family Tree reimagines the possibilities of family trees with an evolving series of exhibits. The authors' works combine genealogical data, visualization, 3D technologies and interactivity to explore and display ancient genealogical relationships. Their new approach may reveal questionable relationships in genealogical records. Moreover, the authors' use of an organic metaphor of a "tree" can be further extended to increase public understanding and engagement. The audience's questions arising from this project show increased curiosity and nuanced questioning about their own family origins and development.

Coastal vegetated habitats, including mangroves, saltmarshes and seagrasses, mitigate climate change by storing atmospheric carbon. Previous blue carbon research has mainly focused on organic carbo...

Nutrient and pesticide pollution are among the major threats to groundwater quality in agriculturally impacted aquifers. Understanding their legacy effects and drivers are important to protect aquifers from exposures to contamination. However, the complexities of groundwater flowpaths make it difficult to predict the time-scales of groundwater flow and contaminant transport. To determine these controls of groundwater nutrient and pesticides in an aquifer system underlying an intensive agricultural area in the Great Barrier Reef catchment, Australia, we sampled tritium (3H) to estimate groundwater-age, nutrient and pesticide concentrations to investigate groundwater contamination, and nitrogen (ẟ15N-NO3−) and oxygen (ẟ18O-NO3−) isotopes to determine groundwater nitrate dynamics. We, then, constructed high-resolution 3D geological and groundwater flow models of the aquifer system to determine the role of the geologic heterogeneity on the observed nutrient and pesticide concentrations. Groundwater 3H derived ages, and nutrient and pesticide concentrations did not follow distinct spatial trends. ẟ15N-NO3− and ẟ18O-NO3− values indicated that nitrification and denitrification processes influenced nitrate dynamics in the aquifer system; however, they were not solely able to explain the entire 3D variability. The 3D geologic modelling identified possible preferential flowpaths and perched systems, which helped to explain the observed groundwater-age, nutrient and pesticide variabilities. Old-groundwater (~100-years) was found in shallow depths ( 25 m), below perched and locally confined systems. Downward increasing groundwater-age, and decreasing nutrient and pesticide concentrations were detected in the unconfined aquifer, while old-groundwater (~160-years) and lower nitrate (

This study was done to partially purification of topoisomerase IB from serum of diabetic patients using Gel filtration technique, by using Sephadex G 100 gel. A single peak in fraction four has been obtained, and the degree of purification (17.1) fold, enzyme yield (108.2%) and specific activity (0.189ng/mg). Kinetics studies for the partial purified enzyme were carried out which showed optimal concentration of substrate which was (0.1ng/ml), Michael's - Menten constant (Km=0.033ng) and maximum velocity (Vmax=0.90 ng/ml), while optimum Temperature was (37C°) and optimum pH was (7.5). The molecular weight of the partial purified enzyme has been determined by gel electrophoresis method, in presence of polyacrylamide gel and sodium dodecyl sulphate (SDS-PAGE) which showed that the approximated molecular weight was (66KD).

Water-to-air carbon dioxide fluxes from tropical coastal waters are an important but understudied component of the marine carbon budget. Here, we investigate drivers of carbon dioxide partial pressure (pCO2) in a relatively pristine mangrove-seagrass embayment on a tropical island (Bali, Indonesia). Observations were performed over eight underway seasonal surveys and a fixed location time series for 55 h. There was a large spatial variability of pCO2 across the continuum of mangrove forests, seagrass meadows and the coastal ocean. Overall, the embayment waters surrounded by mangroves released CO2 to the atmosphere with a net flux rate of 18.1 ± 5.8 mmol m-2 d-1. Seagrass beds produced an overall CO2 net flux rate of 2.5 ± 3.4 mmol m-2 d-1, although 2 out of 8 surveys revealed a sink of CO2 in the seagrass area. The mouth of the bay where coral calcification occurs was a minor source of CO2 (0.3 ± 0.4 mmol m-2 d-1). The overall average CO2 flux to the atmosphere along the transect was 9.8 ± 6.0 mmol m-2 d-1, or 3.6 × 103 mol d-1 CO2 when upscaled to the entire embayment area. There were no clear seasonal patterns in contrast to better studied temperate systems. pCO2 significantly correlated with antecedent rainfall and the natural groundwater tracer radon (222Rn) during each survey. We suggest that the CO2 source in the mangrove dominated upper bay was associated with delayed groundwater inputs, and a shifting CO2 source-sink in the lower bay was driven by the uptake of CO2 by seagrass and mixing with oceanic waters. This differs from modified landscapes where potential uptake of CO2 is weakened due to the degradation of seagrass beds, or emissions are increased due to drainage of coastal wetlands.

Our understanding of how wet-dry tropical catchments process water and solutes remains limited. In this study, we attempt to gain understanding of water and dissolved organic carbon (DOC) transport, storage, and mixing in a 126 km(2) catchment of northern Australia. We developed a coupled, tracer-aided, conceptual rainfall-runoff model (SAVTAM) that simultaneously calculates water, isotope, and DOC-based processes at a daily time step. The semidistributed model can account for the marked hydrological distinction between savanna woodlands and adjacent seasonal wetlands. Using the calibrated model, we tracked the fluxes and derived the age of water in fluxes and storages. Model output matched the seasonal variability, controlled by seasonal rainfall, which switched on and off water and carbon flow pathways from the savanna to seasonal wetlands and ultimately to the perennial river. Such hydrological connectivity is modulated by the karst aquifer system that continuously contributes older waters (decades to century old) to maintain relatively stable and older streamflow during the dry season (average stream water age = 9.7 to 16.2 years). Such older waters occur despite a rapid, monsoon-driven streamflow response. The DOC fluxes were largely sourced from the wetland and riparian forest that transported DOC in the order of 1.9 t C km(-2) year(-1) to the stream, which was on average 90% of the total simulated DOC exports of 2 t C.km(-2).year(-1). We conclude that coupled simulation of water and biogeochemistry is necessary to generate a more complete picture of catchment functioning, particularly in the tropics.

Most research evaluating the potential of mangroves as a sink for atmospheric carbon has focused on carbon burial. However, the few studies that have quantified lateral exchange of carbon and alkalinity, indicate that the dissolved carbon and alkalinity export may be several-fold more important than burial. This study aims to investigate rates and drivers of alkalinity, dissolved carbon and greenhouse gas fluxes of the mangrove-dominated Shark River estuary located in the Everglades National Park in Florida, USA. Time series and spatial surveys were conducted to asses total alkalinity (TAlk), organic alkalinity (OAlk), dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Dominant metabolic processes driving dissolved carbon and greenhouse gas dynamics varied along the estuary salinity gradient. Dissolved carbon and greenhouse gas concentrations were strongly coupled to porewater input, which was examined using Rn-222. Shark River was a source of CO2 (92 mmol/m­2/d), CH4 (60 µmol/m­2/d) and N2O (2 µmol/m­2/d) to the atmosphere. Dissolved carbon export (DIC = 142 mmol/m­2/d, DOC = 39 mmol/m­2/d) was several-fold higher than burial (~28 mmol/m2/d) and represents an additional carbon sink. Furthermore, the estuary was a source of TAlk (97 mmol/m­2/d) to the coastal ocean, potentially buffering coastal acidification. Despite accounting for only a small share of TAlk, OAlk had a large effect on the estuarine pH. By integrating our results with previous studies, we argue that alkalinity, dissolved carbon and greenhouse gas fluxes should be considered in future blue carbon budgets.

Mangroves provide vital ecosystem services at the dynamic interface between land and oceans. Recent reports of mangrove mortality suggest that mangroves may be adversely affected by climate change. Here, we review historical mortality events from natural causes (all mortality other than deforestation, land use change and pollution) and provide a global assessment of mortality drivers. Since the 1960's approximately 36,000 ha of mangrove mortality has been reported (0.2% of total mangrove cover in 2011) in 47 peer reviewed articles. Due to the uneven global distribution of research effort, it is likely that mangrove mortality events go unreported in many countries. It is therefore difficult to assess temporal changes in mortality due to the small number of reports and increasing effort in observations in recent years. From the published literature, approximately 70% of reported mangrove loss from natural causes has occurred as a result of low frequency, high intensity weather events, such as tropical cyclones and climatic extremes. Globally, tropical cyclones have caused the greatest area of mangrove mortality, equivalent to 45% of the reported global mangrove mortality area from events over six decades. However, recent large-scale mortality events associated with climatic extremes in Australia account for 22% of all reported historical forest loss. These recent mortality events suggest the increasing importance of extreme climatic events, and highlight that mangroves may be important sentinels of global climate change. Increasing frequency, intensity and destructiveness of cyclones as well as climatic extremes, including low and high sea level events and heat waves, have the potential to directly influence mangrove mortality and recovery, particularly in mid latitudes.

Silvicultural thinning treatments to restore whitebark pine (Pinus albicaulis) are widely used in subalpine forests throughout the western United States (US) and Canada. The objectives of these treatments are to (1) improve the condition of whitebark pine at all ages, (2) to improve seedling recruitment processes, and (3) mitigate the damage caused by mountain pine beetle (MPB; Dendroctonus ponderosae) and white pine blister rust (WPBR; caused by the fungus Cronartium ribicola). However, there is some disagreement about the ecological basis of restoration and a paucity of information on the effects these activities – few treatments have been monitored to assess their success. We investigated the ecological effects of silvicultural restoration treatments in whitebark pine forests and evaluated their success by retrospectively sampling five treatment sites in the western US 6–10 years after implementation. We found strong evidence of growth release at a site previously characterized by closed-canopy stands. Growth responses in more open, park-like stands, however, were variable: we found weak growth increases at one site, weak growth decreases at another and no response at two other sites. At the site with strong growth increases, trees with previous damage from WPBR infection had growth increases similar to uninfected trees. We found low rates of whitebark pine seedling recruitment overall, and no increase in whitebark pine recruitment associated with treatments at any site. However, at one site, treated stands had higher regeneration of non-target species than did untreated stands. Post-treatment mortality (mostly from the late 2000s MPB outbreak) was significantly lower in the treated stand at the closed-canopy site; at the other sites, there was no difference in mortality between treated and untreated stands. The treatments had little detectable effect on short-term growth-climate relationships, although our analyses revealed that whitebark pine growth at our sites was more temperature limited than water limited. While some management goals were achieved, many were not, and there were some unintended consequences. Our results call for a closer examination of the ecological basis of silvicultural restoration treatments in whitebark pine and an expanded use of adaptive management.

CO2 and CH4 emissions from estuaries of the Southern Hemisphere are greatly under-represented in global estuary emission estimates. This study quantifies seasonal pCO2 and CH4 concentrations and emissions along the salinity gradient of three tropical mangrove-dominated estuaries in Australia. A combination of approaches (i.e. carbon stable isotopes, groundwater inputs, riverine contribution, freshwater flushing times) was used to assess the spatial and seasonal variable factors that controlled the estuary surface water CO2 and CH4 concentrations and hence emissions. Overall, CO2 and CH4 emissions ranged from 21.6 to 110.4 mmol m−2 d−1 and 40.3 to 1047.1 μmol m−2 d−1, respectively, and were within or at the high end compared to estuaries in Australia and globally. In the Johnstone River estuary, high emissions were predominantly driven by groundwater and riverine carbon inputs with exports of CO2 and CH4 to the ocean expected in the wet season. In the Fitzroy River estuary and Constant Creek estuary, in situ production and terrestrial carbon inputs were likely the main factors controlling CO2 and CH4 emissions. The contribution of riverine CO2 may be more important to overall CO2 emissions than the riverine CH4 to overall CH4 emissions in estuaries. The relative contribution of in situ production, the exchange with adjacent coastal habitats (i.e. mangroves, inter-tidal flats), and terrestrial, riverine and groundwater inputs in the wet and in the dry season determined whether CO2 and CH4 were fully ventilated within the estuaries or exported to the open ocean. The revised global estimate for estuary CO2 emission of the latitude 0 to 23.5 °S is 52.1 ± 16.1 mmol m−2 d−1, which is 15% higher than a recent estimate of this latitudinal region.

Mangrove forests can be a source or a sink of nitrous oxide (N2O) to the atmosphere, but seasonal mangrove N2O dynamics are not well understood. We used continuous high-resolution N2O concentration data to construct seasonal budgets of N2O in two tropical mangrove-lined creeks for both the wet and dry seasons. Furthermore we used N stable isotope analysis to constrain the pathways of N2O production and consumption within these creeks. Calculated water-air fluxes were within a range typical of undisturbed mangroves, however obvious seasonal differences in N2O dynamics were observed at the two sites. The mangrove systems were a net source of N2O to the atmosphere during the dry season and a net sink during the wet season. In the wet season we propose that increased allochthonous carbon enhances N2O consumption by denitrification. Combining the seasonal fluxes, the Fitzroy mangrove system, which received a continual input of allochthonous nitrate (NO3−), was a net source of N2O, while the Burdekin mangrove system was close to a net N2O balance. Interpreted in the context of DIN and N2O concentrations, the N2O isotopic values observed in the dry season point to fungal denitrification as the most likely pathway of N2O production. This study shows that subtle shifts in seasonal nutrient supply regulate mangrove N2O production and consumption.

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 ?atm to 8030 ?atm, 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.

Aquatic carbon exports are an understudied component of catchment carbon budgets. For drained agroecosystems, the role of this aquatic pathway in offsetting the terrestrial carbon sink is unknown. Here, we present findings on the complete annual carbon budget of a subtropical agricultural floodplain in Australia. We quantified net ecosystem exchange (NEE) using eddy covariance, and aquatic carbon fluxes from drainage canals over an annual cycle, including atmospheric exchange of aquatic CO2 and CH4, as well as lateral exports of dissolved organic, inorganic and particulate carbon. The floodplain was a large atmospheric CO2 sink, with an annual NEE of −900 g C m−2 yr−1 driven by the sugarcane growing season. Aquatic carbon fluxes were estimated at 24, 16, and 0.05 g C m−2 yr−1 for lateral export, CO2 and CH4 evasion, respectively. Between 70% and 91% of aquatic carbon was lost during flood events which occurred only 12% of the time. From these measurements and estimates of other carbon inputs and outputs from farm operations, the net ecosystem carbon budget was close to neutral at −100 (error range −289 to 215) g C m−2 yr−1. Compared to other drained wetlands, the aquatic carbon flux was a minor component of the carbon budget.

We investigated coral reef carbonate chemistry dynamics and metabolic rates using an automated system that measured total alkalinity (TA, 30 min intervals), pH on the total scale (pHT, 10 min intervals) and the partial pressure of carbon dioxide (pCO2, 1 min intervals) over 2 weeks at Heron Island (Great Barrier Reef, Australia). The calculation of pHT (using the pCO2 and TA pair) and pCO2 (using the pH and TA pair) had similar values to the measured pHT and pCO2 values. In contrast, calculated TA from the pCO2-pH pair showed a large discrepancy with measured TA (average difference between measured and calculated TA = 52 μmol kg−1). High frequency sampling allowed for detailed analysis of the observations and an assessment of optimum sampling intervals required to characterise the net ecosystem calcification (NEC) and production (NEP) using a slack water approach. Depending on the sampling interval (30 min–2 h time steps) used for calculations, the estimated daily NEC and NEP could differ by 12% and 30%, respectively. Abrupt changes in both NEC and NEP were observed at dawn and dusk, with positive NEC during these periods despite negative NEP. Integrating NEC and NEP over a full diel cycle using 1 or 2 h integration time steps resulted in small differences of 2–7% for NEC and 1–3% for NEP. A diel hysteresis pattern rather than a simple linear relationship was observed between the aragonite saturation state (Ωar) and NEC. The observed hysteresis supports recent studies suggesting that short-term observations of seawater Ωar may not be a good predictor of long-term changes in NEC due to ocean acidification. The slope of the DIC to TA relationship was slightly higher (0.33) in 2014 than in an earlier study in 2012 (0.30). The automated, high frequency sampling approach employed here can deliver high precision data and can be used at other coral reef research stations to reveal long-term changes in NEC and NEP potentially driven by ocean acidification, eutrophication or other local changes.

Large uncertainties remain in global estuarine CO2 and CH4 emissions estimates due to spatial heterogeneity, differences in methodologies and insufficient data at key locations. This study utilised novel techniques to integrate high-resolution temporal measurements of dissolved CO2 and CH4 and gas transfer velocity, within an urbanised subtropical estuary (Coffs Creek, Australia). An intensive four-station 25hr moving time series approach accounted for diurnal, tidal and spatial trends along an estuarine salinity gradient. Using 185 floating chamber measurements, results revealed major differences in emission rates over short distances. Average CO2 emission rates ranged from 16.7 to 84.4 mmol m−2 day−1 from lower to upper estuary respectively (averaged 49.0 mmol m−2 day−1). The CH4 emissions ranged from 38.8 to 193.4 μmol m−2 day−1 (averaged 115.0 μmol m−2 day−1), equating to 2.4% of the average CO2 emissions, when converted to global warming potential CO2 equivalent (over 100 years). Conservative mixing plots revealed a mid-estuary source of groundwater and porewater exchange that corresponded with a source of pCO2 and pCH4 in the mangrove lined portion of the estuary. Between the mouth and upper-estuary, a 230-fold change in gas transfer velocity (k600) (0.1–25.9 cm hr−1), 130-fold change in CO2 fluxes (1.6–202.6 mmol m−2 day−1) and 260-fold change of CH4 fluxes were observed (2.6–671.1 μmol m−2 day−1). Current velocity was the most important driver of k600 in the lower estuary (r2 = 0.37, p

The growing importance of resolving ecosystem carbon budgets has resulted in more studies integrating terrestrial and aquatic carbon fluxes. Although recent estimates highlight the importance of inland waters in global carbon budgets, the extent to which aquatic pathways contribute to the net ecosystem carbon budget (NECB) of different ecosystems remains poorly understood. Here, we provide a cross-ecosystem review of annual carbon budgets integrating terrestrial and aquatic fluxes. Large variability in the proportion of aquatic carbon offset to terrestrial net ecosystem productivity (NEP) was observed, with aquatic offsets ranging from

We investigated whether submarine groundwater discharge (SGD) traced by radon (222Rn, a natural groundwater tracer) may drive carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) in surface waters in Chowder Bay, a marine embayment in Sydney Harbour, Australia. A radon mass balance revealed significant groundwater discharge rates into the bay (8.7 ± 5.8 cm d−1). The average CO2, CH4, and N2O concentrations in the subterranean estuary were 3.5, 7.2, and 2.8 times higher than the average surface water concentrations, indicating the possibility of coastal groundwater as a source of greenhouse gases to the bay. SGD-derived fluxes of greenhouse gases were 5.02 ± 2.28 mmol m−2 d−1, 5.63 ± 2.55 μmol m−2 d−1, and 1.72 ± 0.78 μmol m−2 d−1 for CO2, CH4 and N2O, respectively. The average CO2 evasion rate from surface water was 2.29 ± 0.46 mmol m−2 d−1 while CH4 and N2O evasion rates were 12.89 ± 3.05 and 1.23 ± 0.25 μmol m−2 d−1 respectively. Therefore, groundwater-derived greenhouse gas fluxes accounted for >100% CO2 and N2O and ∼43% of CH4 surface water evasion, indicating SGD is likely an important source of greenhouse gases to surface waters. However, this may be due to observations being performed near the SGD source, which may overestimate its contribution to the wider Sydney Harbour. Over a 20-year time frame, the combined emissions of CH4 and N2O from surface waters to the atmosphere accounted for 25% of the total CO2-equivalent emissions. Although this study gives preliminary insight into SGD and greenhouse gas dynamics in Sydney Harbour, more spatial and temporal resolution sampling is required to fully constrain these processes.

This study was conducted to purifity Glucose 6-phosphate dehydrogenase from diabetic patients by gel filtration technique on Sephadex G100 and determine the molecular weight of enzyme, concentration and kinetic constant [Km, Vmax], study the effect of optimum temperature, substrate, pH. The study includes [60] patients with diabetes mellitus and [60] healthy individual as control. The activity of G6PD was measured after precipitated by [75%] Ammonium Sulfate concentration, using [Tris-HCl] buffer at pH 8.2. The specific activity was calculated [21.5UI\mg], total activity [706.8UI], number of purification [3.45] enzyme yield [23.188%] and enzyme activity [17.67UI\ml]. and the molecular weight were [57.82] k.D. The effect of substrate concentration was found to be increased with increasing substrate concentration. The optimum pH was found to be [8.4] and the optimum temperature was [38C]. Michaelis- Menten [Km] value for the enzyme was [3.33mM] and Vmax value was [0.263IU\ml ].

Temperate Highland Peat Swamps on Sandstone (THPSS) are upland wetlands, similar to fens in the Northern Hemisphere and are found at the headwaters of low-order streams on the plateaus of Eastern Australia. They are classified as endangered ecological communities under State and National legislation. Previous works have identified particular geomorphic characteristics that are important to carbon storage in these low energy sediment accumulation zones. Changes in the geomorphic structure of THPSS, such as channelisation, may have profound implications for carbon storage. To assess the effect of channelisation on carbon budgets in these ecosystems it is essential to identify and quantify differences in carbon export, emissions and stocks of carbon of intact swamps and those that have become channelised. We undertook seasonal sampling of the perched swamp aquifers and surface waters of two intact swamps and two channelised fills in the Blue Mountains of New South Wales, Australia, to investigate differences in carbon exports and emissions between the two swamp types. We found that channelised fills' mean CO 2 emissions were almost four times higher than intact swamps with mean CH 4 emissions up to five times higher. Annual fluvial carbon exports for channelised fills were up to 18 times that of intact swamps. Channelised fill exports and emissions can represent up to 2% of the total swamp carbon stocks per annum which is 40 times higher than the intact swamps. This work clearly demonstrates that changes in geomorphic structure brought about by incision and channelisation results in profound changes to the carbon storage function of THPSS.

Continuous high-resolution surface water pCO2 and δ13C-CO2 and 222Rn (dry season only) were measured over two tidal cycles in the wet and dry season in three tropical tidal mangrove creeks on the north-eastern coast of Queensland, Australia. Mangrove surface water pCO2 followed a clear tidal pattern (ranging from 387 to 13,031 µatm) with higher pCO2-values in the wet season than in the dry season. The δ13C-CO2 in the mangrove waters ranged from −21.7 to −8.8‰ and was rather indicative of a mixed source than a distinct mangrove signature. Surface water CO2 was likely driven by a combination of mangrove and external carbon sources, e.g. exchange with groundwater/pore water enriched in 13C, or terrestrial carbon inputs with a significant contribution of C4-vegetation (sugar cane) source. The kinetic and equilibrium fractionation during the gas exchange at the water-atmosphere interface may have further caused a 13C-enrichment of the CO2 pool in the mangrove surface waters. Average CO2 evasion rates (58.7–277.6 mmol m−2 d−1) were calculated using different empirical gas transfer velocity models. Using our high-resolution time series data and previously published data, the average CO2 flux rate in mangrove ecosystems was estimated to be 56.5 ± 8.9 mmol m−2 d−1, which corresponds to a revised global mangrove CO2 emission of 34.1 ± 5.4 Tg C per year.

Transcutaneous spinal cord stimulation (TSCS) has demonstrated potential to beneficially modulate spinal cord motor and autonomic circuitry. We are interested in pairing cervical TSCS with other forms of nervous system stimulation to enhance synaptic plasticity in circuits serving hand function. We use a novel configuration for cervical TSCS in which the anode is placed anteriorly over ~C4–C5 and the cathode posteriorly over ~T2–T4. We measured the effects of single pulses of TSCS paired with single pulses of motor cortex or median nerve stimulation timed to arrive at the cervical spinal cord at varying intervals. In 13 participants with and 15 participants without chronic cervical spinal cord injury, we observed that subthreshold TSCS facilitates hand muscle responses to motor cortex stimulation, with a tendency toward greater facilitation when TSCS is timed to arrive at cervical synapses simultaneously or up to 10 milliseconds after cortical stimulus arrival. Single pulses of subthreshold TSCS had no effect on the amplitudes of median H-reflex responses or F-wave responses. These findings support a model in which TSCS paired with appropriately timed cortical stimulation has the potential to facilitate convergent transmission between descending motor circuits, segmental afferents, and spinal motor neurons serving the hand. Studies with larger numbers of participants and repetitively paired cortical and spinal stimulation are needed.

Rivers and streams play a central role in global carbon budget, but our knowledge is limited on the magnitude and extent of urbanization influence on riverine methane (CH4) dynamics. In this study, we investigated dissolved CH4 (dCH4) concentration and CH4 diffusive fluxes in 27 river segments of two 4th-order and three 3rd-order tributary rivers to the Yangtze River in China, which drained land areas with varied urbanization intensities. We found that urban development was the key factor responsible for high fluvial dCH4 concentration and diffusive flux, exceeding the influence of agricultural farming, and these headwater rivers were over-saturated in CH4 with respect to atmospheric equilibrium. dCH4 concentration (3546 ± 6770 nmol L-1) in the river segments draining higher urban area (20% ≤ urban land proportion ≤ 46%) was 5-6 times higher than those (615 ± 627 nmol L-1 and 764 ± 708 nmol L-1) in the river segments draining less urban area (0.1% ≤ urban land proportion < 2% and 2 ≤ urban land proportion < 20%). River segments draining higher urban area also acted as important sources of CH4 to the atmosphere (8.93 ± 14.29 mmol m-2 d-1). Total nitrogen (TN) concentration in river water showed the best prediction capacity when compared to other water parameters. Based on urban land use grouping, nutrient elements could predict dCH4 well in rivers draining higher urban areas (urban ≥ 2%), which also reflected the lateral input of pollutants (TN, ammonia nitrogen, and total phosphorus). River bottom sediment fraction contributed to trapping organic matter and nutrients as well as to oxic and anoxic conditions, thereby determining reach-scale spatial patterns of dCH4 concentration. These findings highlight that combining distal geomorphic and hydrologic drivers can be effective in determining the relationship between riverine CH4 and the proximal controls (e.g., nutrients, dissolved oxygen, dissolved organic carbon), as well as in identifying their key drivers. Being rapid urbanization a common feature of catchments worldwide, our results suggest riverine CH4 emissions will increase into the future.

Few studies exist on the contribution of subterranean estuaries (STEs) to the oceanic uranium (U) budget. Here, we estimate the dissolved U fluxes out of a quartz sand STE located on the east coast of Australia. Our results indicate that the advective flow of seawater in permeable sands enhances cycling of U in the STE. Dissolved U concentrations ranged from 25 nM in the STE to an effective zero salinity end-member of 3.8 nM in the surface estuary. The dissolved U (salinity corrected) concentrations were positively correlated to Fe (r2 = 0.49 p