seasonal variation

季节变化
  • 文章类型: Journal Article
    本研究通过研究印度南部主要内陆水产养殖区内四个河口河流的水质,探讨了内陆水产养殖对河口生态系统的环境影响。在这个地区,广泛和密集的水产养殖实践是常见的,对河口健康构成潜在挑战。该研究探索了高斯消除方法(GEM)和机器学习技术的预测能力,特别是多元线性回归(MLR)和支持向量回归(SVR),在预测这些河流的水质指数时。通过使用决定系数(R2)和平均平均绝对百分比误差(MAPE)等性能指标进行综合评估,MLR和SVR显示出更高的预测效率。值得注意的是,在机器学习模型中使用关键水参数作为输入也更有效。生化需氧量(BOD)是一个关键的水参数,由MLR和SVR识别,在预测水质方面表现出很高的特异性。这表明MLR和SVR,纳入关键水参数,应优先考虑集约化水产养殖区未来的水质监测,促进及时的警告和干预措施,以保护水质。
    This study delves into the environmental impact of inland aquaculture on estuarine ecosystems by examining the water quality of four estuarine streams within the key inland aquaculture zone of South India. In this region, extensive and intensive aquaculture practices are common, posing potential challenges to estuarine health. The research explores the predictive capabilities of the Gaussian elimination method (GEM) and machine learning techniques, specifically multi-linear regression (MLR) and support vector regressor (SVR), in forecasting the water quality index of these streams. Through comprehensive evaluation using performance metrics such as coefficient of determination (R2) and average mean absolute percentage error (MAPE), MLR and SVR demonstrate higher prediction efficiency. Notably, employing key water parameters as inputs in machine learning models is also more effective. Biochemical oxygen demand (BOD) emerges as a critical water parameter, identified by both MLR and SVR, exhibiting high specificity in predicting water quality. This suggests that MLR and SVR, incorporating key water parameters, should be prioritized for future water quality monitoring in intensive aquaculture zones, facilitating timely warnings and interventions to safeguard water quality.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    清洁的空气对于地球上所有生命形式的生存至关重要。然而,最近见证了城市污染水平的巨大升级。因此,我们有责任破译应对措施。在透视中,本研究是为了评估PM10和PM2.5的负荷,金属成分,气态污染物,来源贡献,九个地点的健康影响和噪音水平,归类为住宅,商业,2019-21年勒克瑙市的工业。季风前PM10,PM2.5,SO2和NO2的平均浓度分别为:138.2±35.2,69.1±13.6,8.5±3.3和32.3±7.4µg/m3,季风后浓度分别为143.0±33.3、74.6±14.5、12.5±2.1和35.5±6.3µg/m3。季风前PM10超出国家环境空气质量标准(NAAQS)的百分比为38.2%,而季风后为43.0%;而PM2.5的相应值分别为15.2%和24.3%。由于冬季反转和高湿度条件,季风后季节显示出更高的颗粒物负荷。与PM2.5相关的元素顺序为Co Clean air is imperative to the survival of all life forms on the planet. However, recent times have witnessed enormous escalation in urban pollution levels. It is therefore, incumbent upon us to decipher measures to deal with it. In perspective, the present study was carried out to assess PM10 and PM2.5 loading, metallic constituents, gaseous pollutants, source contributions, health impact and noise level of nine-locations, grouped as residential, commercial, and industrial in Lucknow city for 2019-21. Mean concentrations during pre-monsoon for PM10, PM2.5, SO2 and NO2 were: 138.2 ± 35.2, 69.1 ± 13.6, 8.5 ± 3.3 and 32.3 ± 7.4 µg/m3, respectively, whereas post-monsoon concentrations were 143.0 ± 33.3, 74.6 ± 14.5, 12.5 ± 2.1, and 35.5 ± 6.3 µg/m3, respectively. Exceedance percentage of pre-monsoon PM10 over National Ambient Air Quality Standards (NAAQS) was 38.2% while that for post-monsoon was 43.0%; whereas corresponding values for PM2.5 were 15.2% and 24.3%. Post-monsoon season showed higher particulate loading owing to wintertime inversion and high humidity conditions. Order of elements associated with PM2.5 is Co < Cd < Cr < Ni < V < Be < Mo < Mn < Ti < Cu < Pb < Se < Sr < Li < B < As < Ba < Mg < Al < Zn < Ca < Fe < K < Na and that with PM10 is Co < Cd < Ni < Cr < V < Ti < Be < Mo < Cu < Pb < Se < Sr < Li < B < As < Mn < Ba < Mg < Al < Fe < Zn < K < Na < Ca. WHO AIRQ + ascertained 1654, 144 and 1100 attributable cases per 0.1 million of population to PM10 exposure in 2019-21. Source apportionment was carried out using USEPA-PMF and resolved 6 sources with highest percent contributions including road dust re-entrainment, biomass burning and vehicular emission. It is observed that residents of Lucknow city regularly face exposure to particulate pollutants and associated constituents making it imperative to develop pollution abetment strategies.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    探索季节变化对冷水鱼肠道菌群的影响对于理解季节变化与冷水鱼的关系具有重要作用。夏季和冬季从亚龙河下游收集了冷水鱼的肠道样本和环境样本。16SrRNA测序结果表明,冷水鱼肠道细菌的组成和多样性存在显着差异。与冬季相比,夏季冷水鱼的肠道细菌的共现网络复杂性更高(总和:节点:256;边缘:20,450;Win:节点:580;边缘:16,725)。此外,从夏天到冬天,在冷水鱼的肠道细菌中,沉积物细菌的贡献(总和:5.3%;Win:23.7%)减少,而水中细菌的贡献(总和:0%;Win:27.7%)增加。归一化随机比率(NST)和基于系统发育bin的零模型分析(iCAMP)推断群落组装机制表明,确定性过程在冷水鱼肠道细菌的微生物组装机制中起着比随机过程更重要的作用。从夏天到冬天,确定性过程对肠道细菌群落组装机制的贡献下降,而随机过程的贡献增加。总的来说,这些结果表明,季节性变化影响了冷水鱼的肠道细菌,并为未来研究了解鱼类对不同环境的适应性提供了潜在的参考。
    Exploring the effects of seasonal variation on the gut microbiota of cold-water fish plays an important role in understanding the relationship between seasonal variation and cold-water fish. Gut samples of cold-water fish and environmental samples were collected during summer and winter from the lower reaches of the Yalong River. The results of the 16S rRNA sequencing showed that significant differences were identified in the composition and diversity of gut bacteria of cold-water fish. Co-occurrence network complexity of the gut bacteria of cold-water fish was higher in summer compared to winter (Sum: nodes: 256; edges: 20,450; Win: nodes: 580; edges: 16,725). Furthermore, from summer to winter, the contribution of sediment bacteria (Sum: 5.3%; Win: 23.7%) decreased in the gut bacteria of cold-water fish, while the contribution of water bacteria (Sum: 0%; Win: 27.7%) increased. The normalized stochastic ratio (NST) and infer community assembly mechanisms by phylogenetic bin-based null model analysis (iCAMP) showed that deterministic processes played a more important role than stochastic processes in the microbial assembly mechanism of gut bacteria of cold-water fish. From summer to winter, the contribution of deterministic processes to gut bacteria community assembly mechanisms decreased, while the contribution of stochastic processes increased. Overall, these results demonstrated that seasonal variation influenced the gut bacteria of cold-water fish and served as a potential reference for future research to understand the adaptation of fish to varying environments.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    背景/目标:最近的研究提供了气候因素对人类健康影响的第一个迹象,特别是那些已经在努力应对内部和神经系统疾病的人特别脆弱。面对不断升级的气候变化,我们的研究探讨了一系列气候因素和季节变化对在Kaiserslautern的诊所接受癫痫发作治疗的患者入院的具体影响.方法:我们的研究包括9366例癫痫患者的数据,这些患者因癫痫发作而入院。我们考虑了德国国家气象局提供的七个气候参数。我们使用Kruskal-Wallis检验来检查上述患者组中入院频率与季节之间的相关性。此外,我们使用条件泊松回归和分布滞后线性模型(DLMs)来仔细检查患者入院频率和所研究的气候参数之间的相关性.还在亚组分析中分析了上述参数,涉及患者的性别和年龄以及根据ILAE2017的癫痫发作分类。结果:我们的结果表明,气候因素,如降水和气压,可以增加一般发作性癫痫患者因癫痫发作入院的频率。相比之下,局灶性癫痫患者不易发生气候变化.因此,在后者患者组中,癫痫发作的入院受气候因素的影响较小。结论:本研究表明,气候因素可能是诱发癫痫发作的触发因素,特别是全身性癫痫患者。这是通过分析与癫痫相关的紧急入院的频率及其与主要气候因素的关系间接确定的。我们的研究与其他研究一致,表明气候因素,如脑梗塞或脑出血,影响患者的健康。
    Background/Objectives: Recent studies provide the first indications of the impact of climate factors on human health, especially with individuals already grappling with internal and neurological conditions being particularly vulnerable. In the face of escalating climate change, our research delves into the specific influence of a spectrum of climatic factors and seasonal variations on the hospital admissions of patients receiving treatment for epileptic seizures at our clinic in Kaiserslautern. Methods: Our study encompassed data from 9366 epilepsy patients who were admitted to hospital due to epileptic seizures. We considered seven climate parameters that Germany\'s National Meteorological Service made available. We employed the Kruskal-Wallis test to examine the correlation between the frequency of admittance to our hospital in the mentioned patient group and seasons. Furthermore, we used conditional Poisson regression and distributed lag linear models (DLMs) to scrutinize the coherence of the frequency of patient admittance and the investigated climate parameters. The mentioned parameters were also analyzed in a subgroup analysis regarding the gender and age of patients and the classification of seizures according to ILAE 2017. Results: Our results demonstrate that climatic factors, such as precipitation and air pressure, can increase the frequency of hospital admissions for seizures in patients with general-onset epilepsy. In contrast, patients with focal seizures are less prone to climatic changes. Consequently, admittance to the hospital for seizures is less affected by climatic factors in the latter patient group. Conclusions: The present study demonstrated that climatic factors are possible trigger factors for the provocation of seizures, particularly in patients with generalized seizures. This was determined indirectly by analyzing the frequency of seizure-related emergency admissions and their relation to prevailing climate factors. Our study is consistent with other studies showing that climate factors, such as cerebral infarcts or cerebral hemorrhages, influence patients\' health.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    蓝莓叶(BBL)是一种天然来源,具有很强的抗氧化活性,但是生物活性化合物和它们的季节变化仍然不清楚。这里,在中国种植的两个南方高灌木品种(“Lanmei”#1和“Jewel”)中鉴定出两大类化合物,包括四种咖啡酰基奎尼酸和八种类黄酮。使用在线HPLC柱后衍生系统发现了主要的生物活性化合物,并确定为新绿原酸(NeoCA),绿原酸(CA),芦丁,金丝桃苷,和异槲皮苷.CA对BBL抗氧化活性的贡献最大。“蓝梅”在芦丁含量和抗氧化活性方面均优于“宝石”(P<0.05)。幼年“宝石”叶的CA含量(CAC)最高,达到17.9%。7月是两个品种在果期后的最佳收获时间。通过便携式近红外(NIR)设备,快速准确地预测了新鲜BBL的总酚含量(TPC)和Trolox等效抗氧化能力(TEAC),低成本,和非破坏性的方式在原地。
    Blueberry leaves (BBL) are a natural source with strong antioxidant activity, but bioactive compounds and their seasonal variation remain vague. Here, two major classes of compounds including four caffeoylquinic acids and eight flavonoids were identified in two southern highbush cultivars (\"Lanmei\" #1 and \"Jewel\") grown in China. Major bioactive compounds were discovered using an online HPLC post-column derivatization system and determined as neochlorogenic acid (NeoCA), chlorogenic acid (CA), rutin, hyperoside, and isoquercitrin. CA contributed the most to the BBL antioxidant activity. \"Lanmei\" showed significant advantages in terms of rutin content and antioxidant activity over \"Jewel\" (P < 0.05). The highest CA content (CAC) of juvenile \"Jewel\" leaves reached 17.9%. July was the optimum harvest time for both cultivars after fruiting stage. Total phenolic content (TPC) and Trolox equivalent antioxidant capacity (TEAC) of fresh BBL were accurately predicted by a portable near-infrared (NIR) device in a rapid, low-cost, and non-destructive way in situ.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    背景:大多数研究推断从1950年代到1990年代,肱骨近端骨折(PHF)的发生率在增加。最近的时间趋势不太清楚。
    目标:我们的主要目标是确定马尔默年龄和性别调整后的PHF成人发病率的时间趋势,瑞典,从1944年到2020年。我们的次要目标是根据年龄描述发病率的变化,每月分布,并将最近几十年的数据与更早的数据进行比较。
    方法:马尔默有一家急诊医院治疗急性骨折。我们通过回顾1944年至2020年17个样本年的相关放射学检查,确定了成人患者(≥18岁)的PHF。我们使用jointpoint分析来估计时间趋势。
    结果:我们在研究期间确定了3031个PHF(3231161人年),73%的妇女平均年龄为69岁(男性平均年龄为59岁)。Joinpoint分析表明,从1944年(52/100000人年)到1977年(120/100000),年龄和性别调整后的PHF发病率增加,此后下降到2020年(85/100000)。冬季有更多骨折的季节性变化,在早期但不是最近几十年。
    结论:马尔默的年龄和性别调整后的PHF发病率增加,瑞典,从1940年代到1977年,此后一直下降到2020年。在较早的冬季而不是最近的几十年中,发现了更多的骨折。
    BACKGROUND: Most studies infer increasing incidence of proximal humeral fractures (PHF) from the 1950´s until the 1990´s. Recent time trends are less clear.
    OBJECTIVE: Our primary objective was to identify time trends in the age- and sex-adjusted adult incidence of PHF in Malmö, Sweden, from year 1944 until 2020. Our secondary objectives were to describe the variation in incidence according to age, the monthly distribution, and to compare data from the two most recent decades with earlier.
    METHODS: Malmö has one emergency hospital where acute fractures are treated. We identified PHF in adult patients (≥ 18 years) by reviewing relevant radiology examinations during 17 sample years from year 1944 to 2020. We used jointpoint analyses to estimate time trends.
    RESULTS: We identified 3 031 PHF during the study period (3 231 161 person years), 73% were sustained by women with mean age of 69 years (mean age in men 59). Joinpoint analyses indicated an increase in the age- and sex-adjusted incidence of PHF from year 1944 (52 per 100 000 person years) until 1977 (120 per 100 000) and thereafter a decrease until 2020 (85 per 100 000). A seasonal variation with more fractures during winter months, was apparent in earlier but not recent decades.
    CONCLUSIONS: The age- and sex-adjusted incidence of PHF increased in Malmö, Sweden, from the 1940´s until year 1977 and thereafter decreased until 2020. More fractures were seen during winter months in earlier but not recent decades.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    本文研究了阿斯塔纳城市污水处理厂中MP的存在和去除,哈萨克斯坦首都。在100-5000μm大小的MP浓度在整个处理阶段进行了分析,采用改进的处理工艺方案,并对其去除效率进行了评价。污水处理厂出水的MP浓度较低(4.06±3.06MP/L至5.44±3.51MP/L),但考虑到每日废水排放量(253,900,000升/天),它可以显著促进水系统的MP污染。在进水中观察到季节性变化,夏季丰度较高,而在废水中没有观察到明显的趋势。污水处理厂达到88.6-93.0%的去除效率,机械处理和颗粒过滤是最有效的,其次是生物处理和紫外线消毒。在观察到的形状中,碎片最丰富(53.9-59.9%),黑色MPs占主导地位(44.7-67.5%)。聚乙烯(PE)是分析的MP中最普遍的聚合物类型(31.6-35.7%)。
    This paper investigated the MP presence and removal in the urban WWTP in Astana, the capital city of Kazakhstan. MP concentrations in the 100-5000 μm size were analyzed across treatment stages with a modified treatment process scheme, and their removal efficiencies were evaluated. The WWTP effluent displayed a low MP concentration (4.06 ± 3.06 MP/L to 5.44 ± 3.51 MP/L), but considering the daily wastewater discharge (253,900,000 L/day), it can significantly contribute to the MP pollution of aquatic systems. Seasonal variation was observed in the influent, with higher abundance during summer, while no significant trend was observed in the effluent. The WWTP achieved an 88.6-93.0 % removal efficiency, with mechanical treatment and granular filtration being the most effective, followed by biological treatment and UV disinfection. Fragments were the most abundant among the observed shapes (53.9-59.9 %) and black MPs dominated (44.7-67.5 %). Polyethylene (PE) emerged as the most prevalent polymer type among the MPs analyzed (31.6-35.7 %).
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    药用植物的抗逆性对药理活性成分的积累至关重要,但生物因子和非生物因子对药用植物的调控机制尚不清楚。探讨土壤养分和微生态对毛虫抗逆性的作用机制,闽县四个季节采集根际土壤和根系,甘肃,以及它们的物理化学性质,以及与根相关的微生物,进行了检查。结果表明,从夏季到秋季,细菌α多样性指数在内圈和根际增加。同时,社区组成和功能发生了很大变化。内生细菌群落的稳定性高于根际细菌,内生细菌群落的复杂性低于根际细菌。土壤有机质(OM),含水量(WC),总钾(TK),总氮(TN)和总氮(TN)已被确定为影响毛虫细菌群落多样性和抗逆性的关键因素。WC,TN,OM和OM从夏季到秋季表现出显著差异(P<0.5)。4个关键土壤理化因子在季节间变化显著(P<0.01)。TN和OM主要通过改变抗氧化酶的活性来改变毛囊的抗逆性。OM和内生细菌多样性的变化会影响可溶性糖的积累,从而改变抗逆性。这四个关键的土壤理化因子显著影响内生细菌的多样性。WC和OM被确定为内生和根际细菌的最重要因素,分别。本研究为毛竹的科学种植提供了研究依据。
    The stress resistance of medicinal plants is essential to the accumulation of pharmacological active ingredients, but the regulation mechanism of biological factors and abiotic factors on medicinal plants is still unclear. To investigate the mechanism of soil nutrient and microecology on the stress resistance of C. pilosula, rhizosphere soil and roots were collected across the four seasons in Minxian, Gansu, and their physicochemical properties, as well as root-associated microorganisms, were examined. The results showed that the bacterial α-diversity indexes increased in the endosphere and rhizosphere from summer to autumn. At the same time, the community composition and function changed considerably. The stability of the endophytic bacterial community was higher than that rhizospheric bacteria, and the complexity of the endophytic bacterial community was lower than rhizospheric bacteria. Soil organic matter (OM), water content (WC), total potassium (TK), and total nitrogen (TN) have been identified as the key factors affecting bacterial community diversity and stress resistance of C. pilosula. WC, TN, and OM showed significant differences from summer to autumn (P < 0.5). Four key soil physiochemical factors changed significantly between seasons (P < 0.01). TN and OM change the stress resistance of C. pilosula mainly by changing the activity of antioxidant enzymes. Changes of OM and endophytic bacterial diversity affect the accumulation of soluble sugars to alter stress resistance. These four key soil physicochemical factors significantly influenced the diversity of endophytic bacteria. WC and OM were identified as the most important factors for endophytic and rhizospheric bacteria, respectively. This study provided the research basis for the scientific planting of C. pilosula.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: English Abstract
    Water use efficiency (WUE) is a key indicator for predicting the impacts of climate change on ecosystem carbon and water cycles. Most studies have explored the changes in the response environment of WUE at a particular scale. Few studies have examined how WUE responds to environments at multiple scales, thus limiting our in-depth understanding of the cross-scale carbon and water cycles. In this study, we measured photosynthesis and transpiration in situ periodically and continuously from June to October 2022 in a community dominated by Artemisia ordosica in Mu Us Sandy Land, and analyzed the seasonal variations in WUE at leaf, canopy, and ecosystem scales. The results showed there were significant seasonal variations in leaf water use efficiency (WUEL), canopy water use efficiency (WUET), and ecosystem water use efficiency (WUEE). WUEL was large in June and small in both August and September, ranging from 0.73-2.98 μmol·mmol-1. Both WUET and WUEE were lowest in June and highest in July and August, ranging from 0.10-7.00 and 0.06-6.25 μmol·mmol-1. WUEL was significantly negatively correlated with stomatal conductance. WUET was significantly positively correlated with canopy conduc-tance and soil water content, and negatively correlated with vapor pressure deficit (VPD). There was a significant positive correlation between WUEE and soil water content (SWC10) in 10 cm soil depth. The structural equation model showed that SWC10 and air temperature affected net photosynthetic rate and transpiration rate by modifying stomatal conductance, and thus affecting WUEL. VPD and SWC10 affected WUET by altering transpiration. SWC10, air temperature, and VPD affected WUEE by regulating ecosystem gross primary productivity. The modelling of carbon and water cycles should thoroughly consider the path and intensity of the effect of environmental factors on WUE at multiple scales.
    水分利用效率(WUE)是预测气候变化对生态系统碳、水循环过程的关键指标。以往研究多从单一观测尺度对WUE响应环境的变化进行探究,鲜有研究对不同观测尺度WUE如何响应环境进行论述,这限制了对跨尺度碳水循环的深入理解。本研究选取毛乌素沙地优势种黑沙蒿群落,于2022年6—10月,利用固定样地测定与原位连续监测方法对黑沙蒿的光合与蒸腾特征进行观测,分析黑沙蒿叶片、冠层和生态系统水分利用效率季节特征及其环境影响因素。结果表明: 叶片水分利用效率(WUEL)与冠层水分利用效率(WUET)和生态系统水分利用效率(WUEE)的季节变化差异明显。WUEL在6月较大,在8、9月较小,波动范围为0.73~2.98 μmol·mmol-1;WUET和WUEE在6月最小,在7、8月最大,波动范围分别为0.10~7.00和0.06~6.25 μmol·mmol-1。WUEL与气孔导度呈显著负相关;WUET与冠层导度和土壤含水量呈显著正相关,与饱和水汽压差呈显著负相关;WUEE与10 cm土层土壤含水量(SWC10)呈显著正相关。结构方程模型表明,SWC10和空气温度通过调节气孔导度影响净光合速率和蒸腾速率,进而影响WUEL;饱和蒸气压差和SWC10通过调节蒸腾速率对WUET产生影响;土壤含水量、空气温度和饱和蒸气压差通过调节生态系统总初级生产力对WUEE产生影响。未来碳水循环的模型拟合应充分考虑环境因子对不同观测尺度WUE的影响路径与强度。.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    河流和水库生态系统被认为是温室气体(GHG)排放的热点,而其特定的水文和生物地球化学过程会影响GHG浓度;然而,很少研究整合河流-水库系统,以确定温室气体浓度的主要驱动因素和与这些系统相关的通量变化。在本研究中,我们研究了塞纳河盆地三个河流-水库系统地表水中温室气体浓度的季节性变化。温室气体浓度的水平和季节性变化在水库之间表现出不同的模式,上游,和下游河流。水库中CH4(甲烷)的浓度明显高于上游和下游河流中观察到的浓度,并且在夏季和秋季显示出更高的值。与CO2(二氧化碳)浓度形成对比,而N2O(一氧化二氮)浓度没有表现出明显的季节性规律。在这些储层中发现了高摩尔比的CH4/CO2,值为0.03,比上游和下游河流高出30和10倍以上,分别。在研究期间,三个河流-水库系统的温室气体过饱和,储层中的平均扩散通量(以CO2eq:CO2当量表示)为810±1098毫克CO2eqm-2d-1、9920±2413毫克CO2eqm-2d-1和7065±2704毫克CO2eqm-2d-1,上游和下游河流,分别。CO2和CH4-CO2分别是河流和水库段GHG扩散通量的主要贡献者,而N2O对三个河流-水库系统中温室气体扩散通量的贡献微不足道。我们的结果表明,GHG浓度和气体转移系数在驱动河流-水库系统不同部分之间的GHG扩散通量方面具有不同的重要性。此外,我们的结果还显示了水库和上游河流对下游河流的水质变量和水文特征的综合影响,强调未来需要对河流-水库系统中的温室气体过程进行额外调查。
    River and reservoir ecosystems have been considered as hot spots for GHG (greenhouse gas) emissions while their specific hydrological and biogeochemical processes affect GHG concentrations; however, few studies integrated river-reservoir systems to identify the dominant drivers of GHG concentrations and flux changes associated with these systems. In the present study, we examined the seasonal variations in GHG concentrations in the surface water of three river-reservoir systems in the Seine Basin. The levels and seasonal variations of GHG concentrations exhibited distinct patterns among reservoirs, upstream, and downstream rivers. The concentrations of CH4 (methane) in the reservoirs were notably higher than those observed in both upstream and downstream rivers and showed higher values in summer and autumn, which contrasted with CO2 (carbon dioxide) concentrations, while N2O (nitrous oxide) concentrations did not show an obvious seasonal pattern. A high mole ratio of CH4/CO2 was found in these reservoirs, with a value of 0.03 and was more than 30 and 10 times higher than that in the upstream and downstream rivers, respectively. The three river-reservoir systems were oversaturated with GHG during the study period, with the average diffusive fluxes (expressed as CO2eq: CO2 equivalent) of 810 ± 1098 mg CO2eq m-2 d-1, 9920 ± 2413 mg CO2eq m-2 d-1, and 7065 ± 2704 mg CO2eq m-2 d-1 in the reservoirs, upstream and downstream rivers, respectively. CO2 and CH4-CO2 were respectively the dominant contributors to GHG diffusive fluxes in river and reservoir sections, while N2O contributed negligibly to GHG diffusive fluxes in the three river-reservoir systems. Our results showed that GHG concentrations and gas transfer coefficient have varying importance in driving GHG diffusive fluxes among different sections of the river-reservoir systems. In addition, our results also show the combined effect of reservoirs and upstream rivers on the water quality variables and hydrological characteristics of downstream rivers, highlighting the future need for additional investigations of GHG processes in the river-reservoir systems.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

公众号