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Objective: Brain somatic mutations in mTOR pathway genes are a major genetic etiology of focal cortical dysplasia type II (FCDII). Despite a greater ability to detect low‐level somatic mutations in the brain by deep sequencing and analytics, about 40% of cases remain genetically unexplained. Methods: We included 2 independent cohorts consisting of 21 patients with mutation‐negative FCDII without apparent mutations on conventional deep sequencing of bulk brain. To find ultra‐low level somatic variants or structural variants, we isolated cells exhibiting phosphorylation of the S6 ribosomal protein (p‐S6) in frozen brain tissues using fluorescence‐activated cell sorting (FACS). We then performed deep whole‐genome sequencing (WGS; >90×) in p‐S6+ cells in a cohort of 11 patients with mutation‐negative. Then, we simplified the method to whole‐genome amplification and target gene sequencing of p‐S6+ cells in independent cohort of 10 patients with mutation‐negative followed by low‐read depth WGS (10×). Results: We found that 28.6% (6 of 21) of mutation‐negative FCDII carries ultra‐low level somatic mutations (less than 0.2% of variant allele frequency [VAF]) in mTOR pathway genes. Our method showed ~34 times increase of the average mutational burden in FACS mediated enrichment of p‐S6+ cells (average VAF = 5.84%) than in bulky brain tissues (average VAF = 0.17%). We found that 19% (4 of 21) carried germline structural variations in GATOR1 complex undetectable in whole exome or targeted gene sequencing. Conclusions: Our method facilitates the detection of ultra‐low level somatic mutations, in specifically p‐S6+ cells, and germline structural variations and increases the genetic diagnostic rate up to ~80% for the entire FCDII cohort. ANN NEUROL 2023;93:1082–1093 [ABSTRACT FROM AUTHOR]

This study offers lessons for overcoming future economic crises by examining whether democratic management helped local governments recover their financial condition. During the Great Recession, local governments were forced to make painful decisions regarding increased taxes and user charges, and cuts in public services. Several case studies provide evidence that citizen participation allows localities to increase property taxes as well as cut public services. However, broader, systematic empirical research is lacking. This study found that local governments with participatory budgeting were more likely to improve their financial condition during the Great Recession. The results allow us to identify the role of citizens in fiscal decision-making, offering lessons on how local governments can overcome possible fiscal crises in the future. [ABSTRACT FROM AUTHOR]

Water pollution disrupts the ecological integrity of urbanized river systems, but its impacts on riverine metabolic processes and carbon fluxes are poorly studied in developing countries. Three seasonal field surveys were combined with two high-resolution measurements and an in situ incubation experiment to investigate the effects of untreated wastewater on organic matter biodegradation and the partial pressure of CO2 (pCO2) along the Mekong–Tonle Sap network around Phnom Penh. High-resolution measurements during the dry-season survey exhibited large downstream increases in pCO2 along the Mekong reaches receiving Tonle Sap inflows carrying urban sewage, contrasting with little spatial variation during a monsoon survey when the Mekong floodwater reversed the Tonle Sap flow. The monsoonal and dry-season surveys revealed flooding-induced homogenization and large spatial divergences in dissolved organic carbon (DOC) concentration and its δ13C and Δ14C between the Tonle Sap and connected Mekong reaches. During the 3-day incubation of Mekong waters, alone or mixed with sewage, a large initial nocturnal increase in pCO2 in sewage-supplemented river water exceeded the subsequent daytime CO2 uptake by phytoplankton photosynthesis varying with light exposure. This, combined with the preferential consumption of labile DOC components displaying protein-like fluorescence, implies sewage-enhanced biodegradation of riverine organic matter. These results suggest that neglecting wastewater-enhanced CO2 production in urbanized river basins during long dry periods can result in a significant underestimation of riverine CO2 emissions. [ABSTRACT FROM AUTHOR]

Background: Retinal migraine is an important differential diagnosis of recurrent transient monocular blindness accompanied by headache when other etiologies are excluded. Here, we report a case of orbital vasculitis which initially mimicked retinal migraine.Case Report: A 47-year-old woman had recurrent episodes of fully reversible transient monocular blindness accompanied by ipsilateral headache for 15 months. The patient's neuroimaging and cardiac and ophthalmologic evaluations were normal. With a diagnosis of retinal migraine, her symptoms remitted in response to prophylactic treatment with topiramate and propranolol for 8 months. Three months after discontinuation of medications, transient monocular blindness recurred. High-resolution vessel wall magnetic resonance imaging revealed enhancement of the ipsilateral orbital vessels. Isolated orbital vasculitis was diagnosed. Complete remission of transient monocular blindness was achieved after steroid pulse therapy.Discussion: Isolated orbital vasculitis should be considered in differential diagnosis of recurrent transient monocular blindness and ipsilateral headache. High-resolution vessel wall magnetic resonance imaging can be helpful for the diagnosis. [ABSTRACT FROM AUTHOR]

Background: Mupirocin is a topical antibacterial drug used for the treatment of staphylococcal infections, including meticillin‐resistant Staphylococcus pseudintermedius (MRSP). The recent emergence of resistance to mupirocin is a major concern in many countries. Objectives: This study investigated the prevalence and genotype of mupirocin‐resistant S. pseudintermedius isolated from pet dogs with pyoderma. Samples: A total of 110 clinical isolates of S. pseudintermedius were collected from dogs with pyoderma (n = 110) between July 2010 and September 2016. All animals were client‐owned dogs. Methods: Low‐ and high‐level mupirocin resistance were evaluated with both the broth microdilution and disk diffusion tests. Mupirocin resistance in S. pseudintermedius isolates was confirmed by genetic analysis of the ileS‐2 and naïve ileS genes. Results: MRSP and meticillin‐susceptible S. pseudintermedius were detected in 69 and 41 dogs, respectively. One MRSP strain was highly resistant to mupirocin and contained the high‐level mupirocin resistance gene ileS‐2. There were no low‐level mupirocin‐resistant isolates. Conclusion and clinical importance: Mupirocin is a useful topical antibacterial for MRSP, but a clinical MRSP isolate that had not previously been exposed to mupirocin exhibited the high‐level mupirocin resistance in phenotype and genotype. Therefore, continuous monitoring for mupirocin resistance is important in small animal practice. [ABSTRACT FROM AUTHOR]

The release of dissolved organic matter (DOM) in forest floors is a dynamic component of organic carbon transformations in forest soils. The biogeochemical processes driving the production and release of dissolved organic carbon and nitrogen (DOC and DON) in forest floors are strongly affected by hydroclimatic conditions during rainfall events. We conducted an exhaustive percolation experiment to examine the pool size and sustained production of mobilizable DOC and DON in Oi, Oe and Oa layers of spruce, larch and beech forest floors. The percolation experiment with small reconstructed soil columns was conducted at 5 and 15 °C for 25 days with a percolation volume equal to 36 mm d − 1 , adding up to a total percolation volume of 900 mm. Percolates were collected at an interval of 5 days and analyzed for DOC and DON. Simultaneously to the periodic analysis of percolates, the CO 2 release was measured. The sustained release of DOM during the last leaching period from day 20 to 25, after 720 mm of percolation, was defined as the production rate of DOM . The cumulative release of DOM was large: in case of the 15 °C treatment, the total amount of DOM extracted for 25 days was on average 1.6% and 2.2% of the total C and N stock, respectively. The largest cumulative release of DOM and CO 2 was observed for the beech samples. The ratio of cumulative CO 2 /cumulative DOC release ranged from 1 to 3 for Oi and Oe samples but was < 0.2 for spruce Oa. No changes in DOC/DON ratios as a result of percolation amount were detected. The production rates indicated a rapid replenishment of DOM pools after leaching. The Q 10 values for the DOM production rates ranged from 2 to 4 and were similar to those for CO 2 production. The positive correlation between DOM and CO 2 production rates in Oi and Oe samples highlights the importance of microbial activity for DOM release. The pool of mobilizable DOM in forest floors seems large enough to provide a sustained rate of DOM release throughout precipitation events under field conditions although the actual rate of mobilization may vary in the field, depending on antecedent conditions and the duration and intensity of the rainfall event. [ABSTRACT FROM AUTHOR]

• Source to estuary surveys revealed specific pollution and dam effects on river GHGs. • Pollution effects on riverine CO 2 , CH 4 , and N 2 O vary with source size and location. • Cascade weirs boost CH 4 production, offsetting CO 2 sinks in eutrophic river-estuary. • δ13C indicates wastewater-derived GHGs and temperature-enhanced CH 4 oxidation. • Basin-specific perturbations warn generalizing eutrophic river-estuary as C sinks. Large uncertainties exist regarding the combined effects of pollution and impoundment on riverine greenhouse gas (GHG) emissions. It has also been debated whether river eutrophication can transform downstream estuaries into carbon sinks. To assess human impacts on the riverine and estuarine distributions of CO 2 , CH 4 , and N 2 O, two source-to-estuary surveys along three impounded rivers in Korea were combined with multiple samplings at five or six estuarine sites. The basin-wide surveys revealed predominant pollution effects generating localized hotspots of riverine GHGs along metropolitan areas. The localized pollution effect was pronounced in the lower Han River and estuary adjacent to Seoul, while the highest GHG levels in the upper Yeongsan traversing Gwangju were not carried over into the faraway estuary. CH 4 levels were elevated across the eutrophic middle Nakdong reaches regulated by eight cascade weirs in contrast to undersaturated CO 2 indicating enhanced phytoplankton production. The levels of all three GHGs tended to be higher in the Han estuary across seasons. Higher summer-time δ13C-CH 4 values at some Nakdong and Yeongsan estuarine sites implied that temperature-enhanced CH 4 production may have been dampened by increased CH 4 oxidation. Our results suggest that the location and magnitude of pollution sources and impoundments control basin-specific longitudinal GHG distributions and estuarine carryover effects, warning against simple generalizations of eutrophic rivers and estuaries as carbon sinks. [Display omitted] [ABSTRACT FROM AUTHOR]

• BDOC measurement via DOC loss is the most accurate among available methods. • DOM optical and molecular indices can act as surrogates for BDOC and dissolved CO 2. • SUVA 254 , HIX, and terrestrial humic- and protein-like FDOM are recommended proxies. • Potentials and limitations of previously proposed DOM indices are critically discussed. Biodegradable dissolved organic carbon (BDOC) constitutes the most labile fraction of dissolved organic matter (DOM), which also functions as a source of CO 2 emissions from inland waters. However, no systematic review is available on DOM indicators of BDOC and CO 2 production potential. Optical and molecular indices can be used to track small changes in DOM composition during biodegradation. In this review, we identified four different methods for measuring BDOC together with their strengths and limitations. In addition, we discuss the potential of using documented optical indices based on absorption and fluorescence spectroscopy and molecular indices based on Fourier transform ion cyclotron mass spectrometry as proxies for estimating BDOC and biodegradation-induced CO 2 production based on previously reported relationships in the literature. Many absorbance- and fluorescence-based indices showed inconsistent relationships with BDOC depending on watershed characteristics, hydrology, and anthropogenic impacts. Nevertheless, several indices, including specific UV absorbance at 254 nm (SUVA 254), humification index (HIX), and terrestrial humic-like fluorescent DOM (FDOM) components, tended to have negative relationships with BDOC in tropical and temperate watersheds under baseflow or drought periods. Protein-like FDOM exhibited the strongest correlation with BDOC in different systems, except during storms and flood events. Despite the limited number of studies, DOM molecular indices exhibited consistent relationships with BDOC, suggesting that the relative abundance of aliphatic formulas and the molecular lability index could act as reliable proxies. The DOM optical indices explain up to 96% and 78% variability in BDOC and CO 2 , respectively; nonetheless, there were limited studies on molecular indices, which explain up to 74% variability in BDOC. Based on literature survey, we recommend several sensitive indices such as SUVA 254 , HIX, and terrestrial humic- and protein-like FDOM, which could be useful indicators of BDOC and dissolved CO 2 in inland water. Future research should incorporate a wider range of geographic regions with various land use, hydrology, and anthropogenic disturbances to develop system- or condition-specific DOM optical or molecular proxies for better prediction of BDOC and CO 2 emissions. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this study was to develop options for a more sustainable catchment management, resulting in a reduction of agricultural non-point pollution of water resources in South Korean agricultural catchments. Therefore, an N budget analysis was conducted, which related N inputs into soil under intensive agriculture to N outputs at both field and catchment scale in a mountainous catchment in South Korea. The N budget of all investigated crops was positive, with total N inputs exceeding N outputs by 2.8 times. Radish showed the highest N uptake efficiency (43–45%), whereas rice showed the lowest with 24–30%. At the catchment scale, agriculture contributed over 90% to the maximum N surplus (473Mg). Rice and radish, with over 100MgN surplus each, contributed the largest part. Comparing these results to the N export in the catchment outlet, it was found that N leaching and surface runoff were the dominant loss pathways, leading to a seasonal inorganic N export of 329Mg. Because fertilizer N was the major N input (>50%) for all crop types except soybean, its reduction was identified as the major scope of action for N savings at the field and catchment scale. The currently observed trend of land use change from annual to perennial crops additionally assists the reduction of N surplus but shows only a spatially limited applicability for the future. Further measures like split applications, application timing to match crop needs and cover crops during the fallow complement the attempt. [Copyright &y& Elsevier]

Summary: Water resources in East Asia are considered particularly vulnerable to climate variability and extremes due to strong hydrologic variability inherent in the monsoon climate and rising water demand resulting from rapid economic growth. To obtain a better understanding of the current status and climate-induced risks concerning surface water quality in East Asia, seasonal and spatial variations in surface water quality were compared among 11 watersheds in eight countries during typical dry and wet periods from 2006 to 2008. While concentrations of dissolved ions tended to be higher during dry periods, concentrations of suspended sediments and dissolved organic matter were significantly higher during wet periods at most sampling locations. Metals with low solubility showed higher total concentrations during wet periods and had strong positive relationships with suspended sediment concentrations. Metals with high partitioning into the dissolved phase exhibited higher concentrations during dry periods at many sites. Seasonal and spatial patterns were distinct along the Lower Mekong River, including much higher monsoonal concentrations of sediment-associated metals and relatively high dry-season concentrations of dissolved As along upper reaches. The results suggest that rainfall variability is crucial in understanding seasonality and climate-induced risks concerning surface water quality in East Asia. [ABSTRACT FROM AUTHOR]

Abstract: An overview is provided of the potential effects of climate change on the watershed biogeochemical processes and surface water quality in mountainous watersheds of Northeast (NE) Asia that provide drinking water supplies for large populations. We address major ‘local’ issues with the case studies conducted at three watersheds along a latitudinal gradient going from northern Japan through the central Korean Peninsula and ending in southern China. Winter snow regimes and ground snowpack dynamics play a crucial role in many ecological and biogeochemical processes in the mountainous watersheds across northern Japan. A warmer winter with less snowfall, as has been projected for northern Japan, will alter the accumulation and melting of snowpacks and affect hydro-biogeochemical processes linking soil processes to surface water quality. Soils on steep hillslopes and rich in base cations have been shown to have distinct patterns in buffering acidic inputs during snowmelt. Alteration of soil microbial processes in response to more frequent freeze–thaw cycles under thinner snowpacks may increase nutrient leaching to stream waters. The amount and intensity of summer monsoon rainfalls have been increasing in Korea over recent decades. More frequent extreme rainfall events have resulted in large watershed export of sediments and nutrients from agricultural lands on steep hillslopes converted from forests. Surface water siltation caused by terrestrial export of sediments from these steep hillslopes is emerging as a new challenge for water quality management due to detrimental effects on water quality. Climatic predictions in upcoming decades for southern China include lower precipitation with large year-to-year variations. The results from a four-year intensive study at a forested watershed in Chongquing province showed that acidity and the concentrations of sulfate and nitrate in soil and surface waters were generally lower in the years with lower precipitation, suggesting year-to-year variations in precipitation as a key factor in modulating the effects of acid deposition on soil and surface water quality of this region. Results from these case studies suggest that spatially variable patterns of snow or summer precipitation associated with regional climate change across NE Asia will have significant impacts on watershed biogeochemical processes and surface water quality, in interactions with local topography, land use change, or acid deposition. [Copyright &y& Elsevier]

Abstract: HPLC–size exclusion chromatography (SEC), coupled with on-line detection of UV absorbance (UVA) and fluorescence, was used to characterize dissolved organic matter (DOM) and its interactions with dissolved metals in a forest stream, a reservoir, and an urban river. Optimization of eluent concentration (20mM) allowed separation of altogether 11 molecular size (MS) fractions when NaClO4 was used as an eluent having minimal disturbance with metals. UVA at 254nm and fulvic-like fluorescence (FFL) at 337/423 (excitation/emission) nm were detected for ‘humic’ fractions, while protein-like fluorescence (PFL) at 278/353nm was detected across the whole MS range. At all sites temporal variations in dissolved organic carbon (DOC) concentrations were well explained by changes in UVA intensity of humic fractions, while PFL intensities of a small MS fraction showed a higher correlation with DOC concentrations at the reservoir. Temporal changes in the concentrations of Al, Cr, Li, Ni, and Fe correlated with PFL intensities of small MS fractions, while variations in the concentrations of As, Co, Mn, and Pb were largely explained by UVA and PFL intensities of humic fractions. The results suggest that HPLC–SEC combined with on-line detection of UVA and PFL can be efficiently used in characterizing DOM and its interactions with metals in surface waters. [Copyright &y& Elsevier]

There is limited information regarding biogeochemical pools and fluxes in maritime tundra ecosystems along the Antarctic Peninsula. To collect baseline information on biogeochemical processes in a tundra ecosystem dominated by two vascular plant species ( Colobanthus quitensis and Deschampsia antarctica) at Biscoe Point off the coast of Anvers Island, we measured pools and fluxes of C and N in transplanted tundra microcosm cores, complemented with sampling of precipitation and surface runoff. Snow and snowmelt from the tundra collection site and soil leachates from the cores were enriched with N and dissolved organic carbon compared to precipitation and snowmelt samples collected at Palmer Station, indicating high loading of N and organic matter from the penguin colonies adjacent to the tundra site. Relatively high values of δ15N in the live and dead biomass of D. antarctica and C. quitensis (5.6–25.1‰) indicated an enrichment of N in this tundra ecosystem, possibly through N inputs from adjacent penguin colonies. Stepwise multiple linear regressions found that ecosystem respiration and gross primary production were best predicted by live biomass of D. antarctica, suggesting a disproportionately high contribution of D. antarctica to CO2 fluxes. The cores with higher δ15N and lower δ13C in the soil organic horizon exhibited higher CO2 fluxes. The results suggest that abundant N inputs from penguin colonies and the competitive balance between plant species might play a critical role in the response of tundra ecosystems along the Antarctic Peninsula to projected climate change. [ABSTRACT FROM AUTHOR]

Abstract: In a competitive and globalized business environment, the need for the green products becomes stronger. To meet these trends, environmental impact assessment besides delivery, cost and quality of products should be considered as an important factor in new product development stage. In this paper, a knowledge-based approximate life cycle assessment system (KALCAS) is developed to assess the environmental impacts of product design alternatives. It aims at improving the environmental efficiency of a product using artificial neural networks, which consist of high-level product attributes and LCA results. The overall framework of a collaborative design environment involving KALCAS is proposed, using engineering solution CO™ based on the distributed object-based modeling and evaluation (DOME) system. This framework allows users to access the product data and other related information on a wide variety of application. This paper explores an approximate LCA of product design alternatives represented by solid models in a collaborative design environment. [Copyright &y& Elsevier]

Although dissolved organic matter (DOM) released from the forest floor plays a crucial role in transporting carbon and major nutrients through the soil profile, its formation and responses to changing litter inputs are only partially understood. To gain insights into the controlling mechanisms of DOM release from the forest floor, we investigated responses of the concentrations and fluxes of dissolved organic carbon (DOC) and nitrogen (DON) in forest floor leachates to manipulations of throughfall (TF) flow and aboveground litter inputs (litter removal, litter addition, and glucose addition) at a hardwood stand in Bavaria, Germany. Over the two-year study period, litter manipulations resulted in significant changes in C and N stocks of the uppermost organic horizon (Oi). DOC and DON losses via forest floor leaching represented 8 and 11% of annual litterfall C and N inputs at the control, respectively. The exclusion of aboveground litter inputs caused a slight decrease in DOC release from the Oi horizon but no change in the overall leaching losses of DOC and DON in forest floor leachates. In contrast, the addition of litter or glucose increased the release of DOC and DON either from the Oi or from the lower horizons (Oe + Oa). Net releases of DOC from the Oe + Oa horizons over the entire manipulation period were not related to changes in microbial activity (measured as rates of basal and substrate-induced respiration) but to the original forest floor depths prior to manipulation, pointing to the flux control by the size of source pools rather than a straightforward relationship between microbial activity and DOM production. In response to doubled TF fluxes, net increases in DOM fluxes occurred in the lower forest floor, indicating the presence of substantial pools of potentially soluble organic matter in the Oe + Oa horizons. In contrast to the general assumption of DOM as a leaching product from recent litter, our results suggest that DOM in forest floor leachates is derived from both newly added litter and older organic horizons through complex interactions between microbial production and consumption and hydrologic transport. [ABSTRACT FROM AUTHOR]

Biogeochemical responses to changing climate and atmospheric deposition were investigated using nitrogen (N) and sulfur (S) mass balances, including dry deposition and organic solutes in the Arbutus Lake watershed in the Adirondack Mountains, New York State. Long-term monitoring of wet-only precipitation (NADP/NTN, 1983–2001) and dry deposition (AIRMoN, 1990–2001) at sites adjacent to the watershed showed that concentrations of SO42− in precipitation, SO42− in particles,and SO2 vapor all declined substantially ( P<0.005) in contrast to no marked temporal changes observed for most N constituents (NH4+ in precipitation, HNO3 vapor, and particulate NO3−), except for NO3− in precipitation, which showed a small decrease in the late 1990s. From 1983 to 2001, concentrations of SO42− in the lake outlet significantly decreased (−2.1 μeq L−1 yr−1, P<0.0001), whereas NO3− and dissolved organic N (DON) concentrations showed no consistent temporal trends. With the inclusion of dry deposition and DON fluxes into the mass balance, the retained portion of atmospheric N inputs within the main subcatchment increased from 37% to 60%. Sulfur outputs greatly exceeded inputs even with the inclusion of dry S deposition, while organic S flux represented another source of S output, implying substantial internal S sources. A significant relationship between the annual mean concentrations of SO42− in lake discharge and wet deposition over the last two decades ( r=0.64, P<0.01) suggested a considerable influence of declining S deposition on surface water SO42− concentrations, despite substantial internal S sources. By contrast, interannual variations in both NO3− concentrations and fluxes in lake discharge were significantly related to year-to-year changes in air temperature and runoff. Snowmelt responses to winter temperature fluctuations were crucial in explaining large portions of interannual variations in watershed NO3− export during the months preceding spring snowmelt (especially, January–March). Distinctive response patterns of monthly mean concentrations of NO3− and DON in the major lake inlet to seasonal changes in air temperature also suggested climatic regulation of seasonal patterns in watershed release of both N forms. The sensitive response of N drainage losses to climatic variability might explain the synchronous patterns of decadal variations in watershed NO3− export across the northeastern USA. [ABSTRACT FROM AUTHOR]

The forest floor in temperate forests has become recognized for its importance in the retention of elevated inputs of dissolved inorganic nitrogen (DIN) and as a source of dissolved organic matter (DOM). A laboratory leaching experiment was conducted over the period of 98 d to examine the origin of dissolved organic carbon (DOC) and nitrogen (DON) in a deciduous forest floor, and the effect of resource availability and microbial activity on the production mechanisms involved. The experiment was composed of different types of treatments: exclusion of specific forest floor layers (no Oi, no Oe) and addition of carbon sources (glucose, cellulose, leaf, wood) and NH4NO3 (nitrogen). The cumulative amount of CO2 evolution was positively related to the availability of C sources at each treatment: glucose>leaf=wood=cellulose>control=no Oe=nitrogen>no Oi. DOC release was related to the amount of C sources but showed no clear correlation with CO2 evolution. An increase in C availability generally led to a reduction in the release of DON as well as DIN. In contrast, the amendment of NH4NO3 reduced the cumulative DOC release but enhanced the release of both DON and DIN. Fresh leaf litter was a more important DOC source than labile substrates (glucose and cellulose) as well as more stable substrates (forest floor materials and wood). Among forest floor layers, more humified horizons (Oe and Oa) were the primary source of DIN and made a similar contribution to DOM release as the Oi layer. The changes in DOM composition detected by a humification index of the leachates, in combination with a shift in the final microbial biomass C, suggested that DOM released from the soluble pools of added litter or the Oi layer contained a substantial amount of microbially processed organic matter. Our study demonstrated the importance of C availability in regulating microbial activity and immobilization of dissolved N in an N-enriched forest floor. However, the discrepancy between substrate lability and DOC production, in combination with a rapid microbial processing of DOC released from labile C pools, illustrated the complicated nature of microbial production and consumption of DOC in the forest floor. [Copyright &y& Elsevier]

In the present study, it was investigated whether autonomic dysfunction could predict prognosis in light-chain (AL) amyloidosis patients. Seventy-two patients with biopsy-proven AL amyloidosis were included and underwent an autonomic function test (AFT) between January 2016 and June 2019. Autonomic failure was evaluated using the Composite Autonomic Severity Score (CASS). Survival curves and the three-year overall survival (OS) rate were estimated using the Kaplan–Meier curve, and the Cox proportional hazards regression method was used to evaluate the variables that influenced survival. Autonomic dysfunction was observed in 69 (96%) patients with AL amyloidosis, and the three-year OS rate was 67%. Generalised autonomic failure (GAF) was observed in 31 (43%) patients. In the Kaplan–Meier curve, the three-year OS rates in patients with sudomotor dysfunction or GAF were lower than that in control patients (35 vs. 84%, and 33 vs. 81%, respectively). In Cox proportional hazards regression model, female, bone marrow plasma cell percentage, left ventricular systolic dysfunction, and GAF were significant independent variables associated with survival. The results of this study indicate that GAF on the AFT is an independent adverse prognostic factor for survival in AL amyloidosis patients. [ABSTRACT FROM AUTHOR]

Objectives: In screening studies of Western patients with cerebellar dysfunction, FMR1 premutations have been detected. A screening study of East Asian patients with presumed essential tremor (ET) did not detect these mutations, possibly because the ET patients did not closely mimic the phenotype of fragile X‐associated tremor/ataxia syndrome (FXTAS). The aim of this study was to estimate the prevalence of FMR1 premutations in a carefully recruited group of ET patients with additional phenotypic features of FXTAS. Materials and Methods: From April 2014 to April 2018, we prospectively recruited patients with ET diagnoses from three tertiary care centers. Demographic and clinical data were collected, as well as data on presence of cerebellar signs and extrapyramidal signs (EPS). Tremor, cerebellar signs, and EPS were evaluated using appropriate clinical rating scales. For ET patients with additional cerebellar signs or EPS, FMR1 mutation analysis and brain magnetic resonance imaging were performed. Results: Six hundred and three ET patients were recruited. Cerebellar signs or EPS were present in 168 (27.9%) of 603. FMR1 CGG repeat analysis was performed in 74 of 168 patients. Fifty‐two of 74 had cerebellar signs only, three had EPS only, and 19 had both neurologic abnormalities. Two patients had a FMR1 premutation and fulfiled both clinical and radiological criteria of FXTAS. Conclusions: Two (2.7%) of 74 patients with presumed ET and additional neurological features were discovered to have FXTAS. The possibility of FXTAS should be considered in patients with ET who exhibit mild cerebellar signs or EPS. [ABSTRACT FROM AUTHOR]

Introduction: Even though gait symptoms are prominent in patients diagnosed with multiple system atrophy with predominant parkinsonism (MSA-P) compared with Parkinson's disease (PD), the gait patterns of MSA-P were not clearly elucidated. We investigated postural instability and gait disturbances in MSA-P compared with PD.Methods: We enrolled 34 drug-naïve patients with PD and 26 with MSA-P, and 18 normal controls in this study. Parkinsonism was evaluated by the Unified Parkinson's disease rating scale (UPDRS) part 3 and cognition was assessed with mini-mental status exam (MMSE). All the enrolled subjects underwent Pedoscan and GAITRite to objectively measure postural stability and gait. We compared the results of posturography and gait analysis among 3 groups, and performed correlation analysis of gait parameters with MMSE, UPDRS part 3 and posturography results.Results: No difference was detected in demographic and clinical variables, except tremor sub-score of UPDRS part 3, urinary symptoms and orthostatic hypotension. MSA-P patients showed larger total anterior-posterior and lateral movement of centre of pressure (COP), and widened base of support than PD patients. In correlation analysis, MMSE score, axial sub-score of UPDRS part 3 and lateral movement of COP were correlated with gait parameters in PD patients, while only axial sub-score was associated in MSA-P patients after controlling for age, sex, height, body weight, education year, and disease duration.Conclusion: Even at an early stage, MSA-P patients demonstrated more postural instability and gait disturbance compared with PD patients, and the related factors with gait disturbance in PD and MSA-P might be different. [ABSTRACT FROM AUTHOR]

Despite the rising interest in understanding how climate change could affect the emissions of greenhouse gases (GHGs) from river systems, including floodplains, we still lack a mechanistic understanding of how changing environmental conditions, such as moisture and nutrient availability, limit the temperature responses of GHG production in floodplain sediments. To examine the environmental co-limitations on the temperature responses of three major GHGs (CO2, CH4, and N2O) produced in floodplain sediments, sediments from a constructed wetland on the floodplain of the lower Han River were incubated for 24 d at four temperatures spanning 4–28 ℃, under three conditions (closed, open/wetting, and open/drying). The net production of all three GHGs exhibited nonlinear temperature responses with gas-specific patterns and magnitudes of response varying over the incubation period. During the later incubation phase, positive temperature responses were weakened for the net production of CO2 and CH4 in the dried treatments, whereas a similar weakening occurred for N2O production in the wet treatments. This, combined with incubation-induced changes in dissolved organic carbon and its fluorescence components, indicated the lack or excess of moisture and associated changes in O2 and organic carbon availability as critical co-limiting factors for the temperature responses of GHG production. Warming decreased δ13C in the CH4 emitted from wet and hypoxic sediments, implying a stronger warming effect on CH4 production over oxidation. Unlike many studies assuming a consistent relationship between temperature and GHG production in sediments irrespective of other environmental conditions, our results suggest that warming effects on the GHG emissions from floodplain sediments would depend on the balance between gas production and consumption under the prevailing constraints of moisture, O2, and labile carbon availability. [ABSTRACT FROM AUTHOR]

Muscle atrophy, a reduction of muscle mass, strength, and volume, results from reduced muscle use and plays a key role in various muscular diseases. In the microgravity environment of space especially, muscle atrophy is induced by muscle inactivity. Exposure to microgravity induces muscle atrophy through several biological effects, including associations with reactive oxygen species (ROS). This study used 3D-clinostat to investigate muscle atrophy caused by oxidative stress in vitro, and sciatic denervation was used to investigate muscle atrophy in vivo. We assessed the effect of Oenothera odorata root extract (EVP) on muscle atrophy. EVP helped recover cell viability in C2C12 myoblasts exposed to microgravity for 24 h and delayed muscle atrophy in sciatic denervated mice. However, the expressions of HSP70, SOD1, and ceramide in microgravity-exposed C2C12 myoblasts and in sciatic denervated mice were either decreased or completely inhibited. These results suggested that EVP can be expected to have a positive effect on muscle atrophy by disuse and microgravity. In addition, EVP helped characterize the antioxidant function in muscle atrophy. [ABSTRACT FROM AUTHOR]

High‐frequency, paired measurements of the partial pressure of CO2 (pCO2) and dissolved O2 were combined with dissolved organic matter (DOM) characterization to investigate diurnal (7:00–19:00) and seasonal variations in CO2 dynamics in the lower Ganges River. Diurnal variations in pCO2 shifted seasonally, concurring with changes in DOM optical properties, biodegradable DOM, and O2 departures from atmospheric equilibrium (ΔO2). Increased pCO2 and CO2 flux (FCO2) in August–September corresponded to monsoonal floods carrying more terrestrial materials. Lower dry‐season pCO2 and FCO2 concurred with higher ΔO2, and exhibited strong relationships with DO and pH, indicating a dominant influence of phytoplankton production. Despite large variations in pCO2, the year‐long positive FCO2 implied that the lower Ganges acted as a CO2 source, reaching 122 mmol m−2 d−1. Increasing hydrologic variability and pollution in the Ganges Basin can amplify pCO2 variations linked to seasonal shifts in terrestrial inputs and phytoplankton production. [ABSTRACT FROM AUTHOR]

Summary: Background: NUDT15 polymorphisms are associated with leukopenia during treatment with thiopurines. However, data regarding its effect on treatment outcomes are scarce. Aims: To investigate the outcomes between NUDT15 normal and intermediate metabolisers in paediatric patients with Crohn's disease (CD) treated with a combination therapy of infliximab (IFX) and azathioprine (AZA). Methods: In this retrospective observational study, 143 patients categorised into the NUDT15 normal and intermediate metaboliser groups were compared based on clinical remission (CR), biochemical remission (BR), mucosal healing (MH) at 1 year treatment, IFX trough levels (TLs), antibodies to IFX (ATIs), 6‐thioguanine nucleotide (6‐TGN) levels, loss of response (LOR) and IFX durability. Results: No significant differences were observed between the groups in CR, BR, MH at 1 year, whereas IFX TLs and ATIs and 6‐TGN levels were comparable. However, LOR (6.5% vs 27.7%, P = 0.025) was significantly lower and IFX durability significantly higher (96.8% vs 80.4% P = 0.027) in the intermediate group. Multivariable Cox proportional hazard regression analysis showed that ATI positivity (hazard ratio (HR): 4.76, 95% CI: 2.25‐10.07, P < 0.001) and the NUDT15 metaboliser group was associated with LOR (HR: 0.18, 95% CI: 0.04‐0.76, P = 0.019). The Kaplan‐Meier survival curves showed that the LOR‐free survival rate was significantly lower in normal metabolisers (log‐rank test P = 0.009). Conclusion: NUDT15 intermediate metabolisers were associated with lower LOR in paediatric patients with CD treated with IFX and AZA combination therapy. This finding may partially explain the longer durability of IFX in Korean children than their counterparts in Western countries. [ABSTRACT FROM AUTHOR]

We report on a 32-year-old woman who developed reversible cortical blindness and right-sided weakness after cesarean section at 36 weeks of gestation, due to preeclampsia. An initial brain MRI demonstrated high signal intensity lesions in the bilateral occipito-parietal and left frontal lobes on T2-weighted and diffusion-weighted imaging. All of the lesions showed low signal intensity on apparent diffusion coefficient (ADC) map, which were compatible with cytotoxic edema, and MR angiography (MRA) showed diffuse vasospasm of the intracranial vessels. A follow-up brain MRI showed that most of the lesions disappeared and the vasospasm also resolved. This case suggests that the cytotoxic edema in preeclampsia may evolve differently from the pattern in cerebral infarction and explains the relatively benign course of the neurological signs in preeclampsia. [Copyright &y& Elsevier]

Dams and wastewater may greatly perturb riverine fluxes of dissolved organic matter (DOM) and CO 2 , yet little is known about the relationships between altered DOM quality and CO 2 emission in eutrophic impounded river systems. A basin-wide field survey of surface water CO 2 and dissolved organic carbon (DOC) was combined with laboratory incubations to examine how dams and urban tributaries delivering treated wastewater influence longitudinal patterns in DOM properties and CO 2 along the impounded Han River traversing Seoul metropolitan area. Fluorescent DOM indices including parallel factor analysis (PARAFAC) components were used to characterize DOM in relation to biodegradable DOC (BDOC). Compared with distinct downstream increases in DOC and CO 2 , BDOC concentration and its proportion in DOC (%BDOC) were highly variable along the mainstem and peaked at urban tributaries. Longitudinal increases in fluorescence index (FI), biological index (BIX), and two PARAFAC components (C2 and C3) contrasted with general decreases in humification index (HIX) and C1, reflecting increasing downstream inputs of anthropogenic DOM. During a 5-day incubation employing continuous CO 2 measurements, the cumulative production of CO 2 in the mainstem water mixed with urban tributary water was significantly higher than the level expected for conservative mixing of the two samples, indicating a synergistic enhancement of DOM biodegradation. Molecular formulas identified by Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) revealed more consumed molecules in the mainstem water and more newly produced molecules in the tributary water over the 5-day incubation, implying abundant labile components in the mainstem water discharged from the upstream dam and highly processed tributary DOM limited in immediately biodegradable organic materials. Downstream increases in CO 2 and DOC along the Han River, combined with the synergistic effect observed in the mixed water, suggest that mixing wastewater-derived DOM with labile autochthonous DOM can enhance CO 2 production in the river system perturbed by impoundment and wastewater. Unlabelled Image • Field survey was combined with lab incubations to study human impact on river carbon. • Dissolved organic matter and CO 2 vary along impounded river with wastewater influence. • Urban tributary mixing enhances organic matter degradation and CO 2 in impounded river. • FT-ICR-MS detects organic matter degradation in impounded river and urban tributary. [ABSTRACT FROM AUTHOR]

Continuous underway measurements were combined with a basin-scale survey to examine human impacts on CO2 outgassing in a highly urbanized river system in Korea. While the partial pressure of CO2 (pCO2) was measured at 15 sites using syringe equilibration, 3 cruises employing an equilibrator were done along a 30 km transect in the Seoul metropolitan area. The basin-scale survey revealed longitudinal increases in surface water pCO2 and dissolved organic carbon (DOC) in the downstream reach. Downstream increases in pCO2, DOC, fluorescence index, and inorganic N and P reflected disproportionately large contributions from wastewater treatment plant (WWTP) effluents carried by major urban tributaries. Cruise transects exhibited strong localized peaks of pCO2 up to 13 000 µatm and 13CO2 enrichment along the confluences of tributaries at an average flow, whereas CO2 pulses were dampened by increased flow during the monsoon period. Fluctuations in pCO2 along the eutrophic reach downstream of the confluences reflected environmental controls on the balance between photosynthesis, biodegradation, and outgassing. The results underscore WWTP effluents as an anthropogenic source of nutrients, DOC, and CO2and their influences on algal blooms and associated C dynamics in eutrophic urbanized river systems, warranting further research on urbanization-induced perturbations to riverine metabolic processes and carbon fluxes.. [ABSTRACT FROM AUTHOR]

Fallout radionuclides have been used successfully worldwide as tracers for soil erosion, but relatively few studies exploit the full potential of plutonium (Pu) isotopes. Hence, this study aims to explore the suitability of the plutonium isotopes 239 Pu and 240 Pu as a method to assess soil erosion magnitude by comparison to more established fallout radionuclides such as 137 Cs and 210 Pb ex . As test area an erosion affected headwater catchment of the Lake Soyang (South Korea) was selected. All three fallout radionuclides confirmed high erosion rates for agricultural sites (> 25 t ha − 1 yr − 1 ). Pu isotopes further allowed determining the origin of the fallout. Both 240 Pu/ 239 Pu atomic ratios and 239 + 240 Pu/ 137 Cs activity ratios were close to the global fallout ratio. However, the depth profile of the 239 + 240 Pu/ 137 Cs activity ratios in undisturbed sites showed lower ratios in the top soil increments, which might be due to higher migration rates of 239 + 240 Pu. The activity ratios further indicated preferential transport of 137 Cs from eroded sites (higher ratio compared to the global fallout) to the depositional sites (smaller ratio). As such the 239 + 240 Pu/ 137 Cs activity ratio offered a new approach to parameterize a particle size correction factor that can be applied when both 137 Cs and 239 + 240 Pu have the same fallout source. Implementing this particle size correction factor in the conversion of 137 Cs inventories resulted in comparable estimates of soil loss for 137 Cs and 239 + 240 Pu. The comparison among the different fallout radionuclides highlights the suitability of 239 + 240 Pu through less preferential transport compared to 137 Cs and the possibility to gain information regarding the origin of the fallout. In conclusion, 239 + 240 Pu is a promising soil erosion tracer, however, since the behaviour i.e. vertical migration in the soil and lateral transport during water erosion was shown to differ from that of 137 Cs, there is a clear need for a wider agro-environmental testing. [ABSTRACT FROM AUTHOR]

This study demonstrated that asymmetrical flow field-flow fractionation (AF4) coupled with on-line UV and fluorescence detection (FLD) and off-line excitation-emission matrix (EEM) fluorescence spectroscopy can be employed to analyze the influence of microbial metabolic activity on the consumption and production of freshwater organic matter. With the AF4 system, organic matter is on-line enriched during a focusing/relaxation period, which is an essential process prior to separation. Size-fractionated chromophoric and fluorophoric organic materials were simultaneously monitored during the 30-min AF4 separation process. Two fractions of different sizes (dissolved organic matter (DOM) and particulate organic matter (POM)) of freshwater samples from three locations (up-, mid-, and downstream) along the Han River basin of Korea were incubated with the same inoculum for 14 days to analyze fraction-specific alterations in optical properties using AF4-UV-FLD. A comparison of AF4 fractograms obtained from pre- and post-incubation samples revealed that POM-derived DOM were more susceptible to microbial metabolic activity than was DOM. Preferential microbial consumption of protein-like DOM components concurred with enhanced peaks of chromophoric and humic-like fluorescent components, presumably formed as by-products of microbial processing. AF4-UV-FLD combined with off-line identification of microbially processed components using EEM fluorescence spectroscopy provides a powerful tool to study the relationship between microbial activity and composition as well as biodegradability of DOM and POM-derived DOM from different origins, especially for the analysis of chromophoric and fluorophoric organic matter that are consumed and produced by microbial metabolic activity. The proposed AF4 system can be applied to organic matter in freshwater samples having low concentration range (0.3–2.5 ppm of total organic carbon) without a pre-concentration procedure. [ABSTRACT FROM AUTHOR]

Despite increasing recognition of storm-induced organic carbon (C) export as a significant loss from the terrestrial C balance, little is known about the biodegradation and chemical transformation of particulate organic carbon (POC) in mountainous river systems. We combined analyses of C isotopes, solution-state H NMR, and lipid biomarkers with biodegradable dissolved organic C (BDOC) measurements to investigate downstream changes of POC composition and biodegradability at a mountainous, mixed land-use watershed in South Korea. Water and suspended sediment (SS) samples were collected in a forested headwater stream, a downstream agricultural stream, and two downstream rivers during peak flow periods of four storm events, using either sequential grab sampling from the headwater stream to the most downstream river within a few hours around the peak flow or sediment samplers deployed during the whole storm event. DOC concentrations exhibited relatively small changes across sites, whereas POC concentrations were highest in the agricultural stream, and tapered along downstream reaches. The δC and δN of SS in the agricultural stream were distinct from up- and downstream signatures and similar to those for erosion source soils and lake bottom sediment, although increases in radiocarbon age indicated continuous compositional changes toward the lake. H NMR spectra of SS and deposited sediment exhibited downstream decreases in carbohydrates and lignin but enrichment of organic structures related to microbial proteins and plant wax. The downstream sediments had more microbial n-alkanes and lipid markers indicating anthropogenic origin such as coprostanol compared to the forest soil n-alkanes dominated by plant wax. While the BDOC concentrations of filtered waters differed little between sites, the BDOC concentrations and protein- to humic-like fluorescence ratios of DOC leached from SS during a 13-day incubation were higher in downstream rivers, pointing to contribution of labile POC components to the enhanced biodegradation. Overall, inputs of microbial and anthropogenic origin, in interplay with deposition and mineralization, appear to substantially alter POC composition and biodegradability during downstream transport, raising a question on the conventional view of mountainous river systems as a passive conduit of storm pulses of POC. [ABSTRACT FROM AUTHOR]

Highlights: [•] DOC dynamics in 1st order forested streams controlled by monsoonal climate. [•] DOC dynamics in higher order agricultural streams driven by rice paddy water inputs. [•] Monsoonal climate controls river-aquifer exchange dynamics. [•] Frequent hydraulic gradient reversals are specific to the monsoonal climate. [ABSTRACT FROM AUTHOR]

Highlights: [•] Decreased uncertainty with distributed, weighted, multi-method discharge estimates. [•] High baseflow at upper elevations, while low elevations are mainly runoff driven. [•] Scale-dependent river discharge suggests ergodic behavior in complex watersheds. [•] Spatiotemporal discharge estimates necessary for accurate basin-wine partitioning. [•] A single annual monsoonal event typically alters streambed characteristics. [Copyright &y& Elsevier]

Summary: Although soil erosion and leaching can transfer a substantial portion of the annual terrestrial carbon (C) increment to aquatic systems, little is known about rapid changes in the amount and characteristics of soil organic C exported from mountainous watersheds during storm events. To trace short-term changes in sources and characteristics of soil organic C exported during storm events, we investigated storm-induced changes in concentrations of particulate and dissolved organic C (POC and DOC) and the stable isotope composition of suspended sediment (SS) in a mountainous, mixed land-use watershed in northern South Korea. Biweekly stream sampling in a headwater forest stream and a watershed outlet receiving agricultural runoff showed that concentrations of SS and POC were higher in the watershed outlet. In both the forest stream and outlet, POC concentrations were lower than DOC concentrations during baseflow, but increased rapidly with rising discharge during intense storms, resulting in higher peak POC concentrations than peak DOC concentrations. When δ 13C and δ 15N were compared between SS and potential source soils during three storm events, SS δ 13C and δ 15N in the forest stream were similar to forest floor δ 13C and δ 15N. SS δ 13C and δ 15N in the watershed outlet reflected the contribution from forest and cropland mineral soils during peak flow, with sand-size SS displaying increasing δ 13C and δ 15N with rising rainfall intensity. The results suggest that storm pulses of POC can be a transient, but dominant pathway of hydrologic C export overwhelming DOC export and that POC sources and characteristics can rapidly change corresponding to varying rainfall intensity. [Copyright &y& Elsevier]

Abstract: The effects of treatment processes on estrogenicity were evaluated by examining estradiol equivalent (EEQ) concentrations in influents and effluents of sewage treatment plants (STPs) located along Yeongsan and Seomjin rivers in Korea. The occurrence and distribution of estrogenic chemicals were also estimated for surface water in Korea and compared with seven other Asian countries including Laos, Cambodia, Vietnam, China, Indonesia, Thailand and Malaysia. Target compounds were nonylphenol (NP), octylphenol (OP), bisphenol A (BPA), estrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2) and genistein (Gen). Water samples were pretreated and analyzed by liquid–liquid extraction (LLE) and gas chromatography/mass spectrometry (GC/MS). The results showed that the treatment processes of Korean STPs were sufficient to reduce the estrogenic activity of municipal wastewater. The concentrations of phenolic xenoestrogens (i.e., NP, OP and BPA) in samples of Yeongsan and Seomjin rivers were smaller than those reported by previous studies in Korea. In most samples taken from the seven Asian countries, the presence of E2 and EE2 was a major contributor toward estrogenic activity. The EEQ concentrations in surface water samples of the seven Asian countries were at a higher level in comparison to that reported in European countries, America and Japan. However, further studies with more sampling frequencies and sampling areas should be carried out for better evaluation of the occurrence and distribution of estrogenic compounds in these Asian countries. [Copyright &y& Elsevier]

We examined the influence of warming and supplemental precipitation on plant production and abundance of the dominant microarthropod, the springtail Cryptopygus antarcticus (Collembola), in tundra dominated by the vascular plants Colobanthus quitensis and Deschampsia antarctica along the Antarctic Peninsula. Tundra cores were placed in plots near Palmer Station where they were warmed with infrared heaters in combination with receiving supplemental precipitation. Diel canopy air and soil temperatures and air vapor pressure deficits in warmed plots were elevated 0.8 °C, 2.2 °C and 0.13 kPa, respectively. After two growing seasons, total aboveground plant production was greater under warming as a result of enhanced production by C. quitensis, which more than offset declines in moss biomass. Total aboveground plant production was also greater under supplemental precipitation primarily as a result of enhanced moss production. Total aboveground plant production was greatest under the combination of warming and supplemental precipitation, primarily as a result of enhanced C. quitensis production. C. antarcticus were more abundant in cores receiving supplemental precipitation and there was a strong treatment interaction; these springtails were most abundant in warmed cores receiving supplemental precipitation. Over 50% of the variability in the abundance of C. antarcticus could be explained by differences in aboveground plant biomass. However, plant production did not appear directly responsible for differences in C. antarcticus abundance; when we examined C. antarcticus abundance per unit of aboveground plant biomass, differences in its abundance among treatments were still apparent implying these differences were not the direct result of plant biomass. The responses of C. antarcticus were consistent with its known moisture and thermal preferences, suggesting that abiotic factors played a dominant role in controlling its abundance. Precipitation regime had large impacts on warming responses and these were species specific, illustrating the importance of future precipitation regimes in predicting system responses to warming. [ABSTRACT FROM AUTHOR]

• A 25-year time series shows recent increases in N/P driven by decreasing P levels. • Harmful algal blooms concur with short-term changes in P, N/P, and temperature. • Cyanobacterial dominance lowers phytoplankton P use efficiency at low N/P. • CO 2 relationship with N/P or Chl a indicates phytoplankton biomass as a CO 2 source. Long-term trends in riverine nutrient availability have rarely been linked to both phytoplankton composition and functioning. To explore how the changing availability of N and P affects not only phytoplankton abundance and composition but also the resource use efficiency of N, P, and CO 2 , a 25-year time series of water quality in the lower Han River, Korea, was combined with additional measurements of riverine dissolved organic carbon (DOC) and CO 2. Despite persistent eutrophication, recent decreases in P relative to N have been steep in the lowest reach, increasing the annual mean mass ratio of N to P (N/P) from 24 (1994–2015) to 65 (2016–2018). While Chl a and cyanobacterial abundance exhibited overall positive and inverse relationships with P concentrations and N/P, respectively, severe harmful algal blooms (HABs) concurred with short-term increases in P and temperature. Microcystis often dominated HABs at low N/P that usually favors N-fixing cyanobacteria such as Anabaena. In the middle and lower reaches, phytoplanktonic P use efficiency was typically lower at low N/P. V-shaped relationships between N/P and CO 2 concentrations, together with longitudinal upward shifts in the inverse relationship between Chl a and CO 2 , implied that eutrophication-enhanced phytoplankton biomass could turn into a significant source of CO 2. after passing a threshold. The combined results suggest that cyanobacterial dominance co-limited by P availability and temperature can lower planktonic P use efficiency, while enhancing riverine CO 2 emissions at low N/P ratios. [Display omitted] [ABSTRACT FROM AUTHOR]

• N 2 O concentrations and isotopes reveal winter surges in wastewater and affected river • Low temperature lowers performance of wastewater N removal producing more N 2 O • Low temperature enhances N 2 O production via denitrification in hypoxic sediment Although eutrophic urban rivers receiving loads of wastewater represent an important anthropogenic source of N 2 O, little is known as to how temperature and other environmental factors affect temporal variations in N 2 O emissions from wastewater treatment plants (WWTPs) and downstream rivers. Two-year monitoring at a WWTP and five river sites was complemented with available water quality data, laboratory incubations, and stable isotopes in N 2 O and NO 3 − to explore how wastewater effluents interact with seasonal changes in environmental conditions to affect downstream metabolic processes and N 2 O emissions from the lower Han River traversing the megacity Seoul. Water quality data from four WWTPs revealed significant inverse relationships between water temperature and the concentrations or fluxes of total N (TN) in effluents. Increased TN fluxes at low temperatures concurred with N 2 O surges in WWTP effluents and downstream rivers, counteracting the long-term decline in TN fluxes resulting from enhanced wastewater treatments. Incubation experiments with river water and sediment, in isolation or combined, implied the hypoxic winter sediment as a large source of N 2 O, whereas the anoxic summer sediment produced a smaller amount of N 2 O only when it was added with oxic water. For both WWTP effluents and downstream rivers, bulk isotope ratios and intramolecular distribution of 15N in N 2 O distinctly differed between summer and winter, indicating incomplete denitrification in the hypoxic sediment at low temperatures as a primary downstream source adding to WWTP-derived N 2 O. Winter surges in wastewater TN and sediment N 2 O release highlight temperature variability as an underappreciated control over anthropogenic N 2 O emissions from increasingly urbanized river systems worldwide. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Soil erosion and associated sediment transfer are among the major causes of aquatic ecosystem and surface water quality impairment. Through land-use and agricultural practices, human activities modify the soil erosive risk and catchment connectivity, becoming a key factor of sediment dynamics. Hence, restoration and management plans of water bodies can only be efficient if the sediment sources and the proportion attributable to different land-uses are identified.To achieve this, we conducted two studies: (1) in Central Switzerland and (2) in South Korea, to investigate the seasonal and spatial dynamics in catchment erosion processes. We applied a compound-specific stable isotope (CSSI) approach using the isotopic (d13C) signature of plant-wax derived long-chain fatty acids (C24:0-C30:0) in source soils, suspended sediments and a lake sediment core to apportion the sources of the suspended sediments in the catchments of Lake Baldegg (Switzerland) and Lake Soyang (South Korea). With the R software package MixSiar (version 3.1.10) we calculated the contribution of the different land-uses to the sediments.Event-based suspended sediment sampling from the five main contributing rivers to Lake Baldegg (up to 10 high flow events over the course of one year) and subsequent compound-specific stable isotope analysis of long-chain fatty acids indicated a strong seasonal variation of the sediment origin in the rivers. In spring, forests are the main contributor to the sediments, rapidly changing to grassland as the main source in early summer. Then, during July and August, the CSSIs are indicating arable lands as the main contributor. Averaged over all events in all rivers, forests are dominating the sediment origin over agricultural land and grasslands.In Korea, we focused on the suspended sediment apportionment in a mountainous catchment, Haean Basin, which experienced rapid agricultural expansion and intensification during the last decades. Large areas of hill slope forests were transformed to paddies and vegetable fields. The intensive agriculture and easily erodible soils are a major reason for increased soil erosion resulting in high suspended sediment loads in the river systems. Our second aim in Korea was to investigate the spatial variation in sediment contribution along Soyang river from the Haean catchment to the hydro-electric reservoir Lake Soyang. In the Haean catchment and as well at four suspended sediment sampling sites along Soyang river we applied the same CSSI approach as in Switzerland, mentioned above. Source soils were identified and differentiated in the Haean catchment and used to apportion the sediment sources within the catchment and along the river. Our results show a clear shift from almost exclusive contribution of vegetable fields and forest soils to the suspended sediments in the headwater catchment to an increased contribution of maize fields downstream towards Lake Soyang. Since the areal proportion of maize in the Lake Soyang catchment is not increasing significantly downstream compared to vegetables, rice fields or forests, our findings are giving strong indication for a higher vulnerability of the agricultural soils where maize is grown. [ABSTRACT FROM AUTHOR]