Global distribution of natural freshwater wetlands and rice paddies,their net primary productivity,seasonality and possible methane emissions   总被引：18，自引：0，他引：18  

I. Aselmann  P. J. Crutzen 《Journal of Atmospheric Chemistry》1989,8(4):307-358

A global data set on the geographic distribution and seasonality of freshwater wetlands and rice paddies has been compiled, comprising information at a spatial resolution of 2.5° by latitude and 5° by longitude. Global coverage of these wetlands total 5.7×10⁶ km² and 1.3×10⁶ km², respectively. Natural wetlands have been grouped into six categories following common terminology, i.e. bog, fen, swamp, marsh, floodplain, and shallow lake. Net primary productivity (NPP) of natural wetlands is estimated to be in the range of 4–9×10¹⁵ g dry matter per year. Rice paddies have an NPP of about 1.4×10¹⁵ g y^–1. Extrapolation of measured CH₄ emissions in individual ecosystems lead to global methane emission estimates of 40–160 Teragram (1 Tg=10¹² g) from natural wetlands and 60–140 Tg from rice paddies per year. The mean emission of 170–200 Tg may come in about equal proportions from natural wetlands and paddies. Major source regions are located in the subtropics between 20 and 30° N, the tropics between 0 and 10° S, and the temperate-boreal region between 50 and 70° N. Emissions are highly seasonal, maximizing during summer in both hemispheres. The wide range of possible CH₄ emissions shows the large uncertainties associated with the extrapolation of measured flux rates to global scale. More investigations into ecophysiological principals of methane emissions is warranted to arrive at better source estimates.  相似文献   

The effect of gross primary production, net primary production and net ecosystem exchange on the carbon fixation by chemical weathering of basalt in northeastern Iceland     

Marin Ivanov Kardjilov  Sigurdur Reynir Gíslason  Gudrún Gísladttir 《Journal of Geochemical Exploration》2006,88(1-3):292

The overall objective of this study is to define and interpret the annual dissolved inorganic carbon (DIC) flux in selected river catchments in North Eastern Iceland. The flux stems primarily from chemical weathering of basalt. The DIC flux out of the catchments is compared with the spatial distribution of the various vegetation communities and their gross primary production (GPP), net primary production (NPP) and net ecosystem exchange (NEE). There is no correlation between the DIC flux and the GPP, but one between DIC and NPP. The DIC flux is highly dependent on the NEE, which in turn is governed by the area extent of wetlands in these catchments. A variation by a factor 5 of the NEE results in a variation by a factor 2.8 in the river dissolved inorganic flux.  相似文献   

湿地水空间效应   总被引：1，自引：0，他引：1  

邓伟 《地球科学进展》2007,22(7):725-729

地球水资源短缺问题日益严重,直接影响自然与经济社会可持续发展.陆地健康水循环和水资源的再生是基于合理的水调节空间.湿地是不可替代的水调节空间,因湿地特殊的水理性质和特有的生物地球化学作用,使湿地具有显著的调蓄地表径流和水体净化功能.人类活动大量破坏湿地,使湿地水空间效应明显下降,极大地削弱了湿地水调节功能.就流域生态、生产、生活用水的协调与保证而言,其合理的湿地配置是解决这一问题的重要基础之一.  相似文献   

Distribution of wetlands and salt lakes in the Yadong region of Tibet based on remote sensing,and their geo-climatic environmental changes     

《China Geology》2022,5(4):637-648

Based on the 16 scenes GF-1 satellite multi-spectral remote sensing images, through the adoption of data processing methods including orthorectification, geometric rectification, data fusion and image mosaic, integrated with field surveys, the remote sensing interpretation signs for the inland wetland types have been built, and the remote sensing survey of inland wetlands in Yadong region has been initiated, with six types of inland wetlands recognized in Yadong region, namely permanent rivers, seasonal rivers, lakes, salt lakes, alpine meadows, and inundated land. The spatial distribution characteristics and the spreading rules of these wetlands have also been revealed. Based on full understanding of the overall characteristics of the inland wetlands in the Yadong region, using the three phases of TM images acquired in 1989, 2003 and 2008 as well as the PMS2 data gathered by GF-1 in 2014, and the wide-range data (WFV3) gathered by GF-1 in 2020. As to the typical salt lakes, a long- time salt lakes transition study was carried out. The results show that the typical salt lakes in Yadong have been shrinking in the past three decades. The average annual shrinkage of Duoqing Co (Co means lake in Tibetan) was stronger than that of Gala Co, which are respective 87.30 hectares (usually short as ha; 1 ha equals to 0.01 km²) /a and 24.20 ha/a; the shrinkage degree of Gala Co was higher than that of Duoqing Co, shrank by 59.27% and 35.73% respectively. Based on the remote sensing survey results and an integrated analysis of the predecessors’ researchers, the reason for the shrinkage of the salt lakes is more inclined to geological factors. Geological process is manifested by a series of extensional faults at the bottom of the lake basin generated from tectonic activities, providing fluid infiltration channels, and inducing the eventual leakage of lake water to the lower strata. The result provides an important instance for understanding the evolution characteristics of wetlands and salt lakes in specific environment of the Tibetan Plateau.©2022 China Geology Editorial Office.  相似文献   

Late Holocene vegetation in the Azraq Wetland Reserve, Jordan     

Wallace B. Woolfenden  Linah Ababneh 《Quaternary Research》2011,76(3):345-351

Shifts in aquatic and terrestrial vegetation associations and hydrology during the past > 3100 yr are indicated by the pollen and sediment sequences in a core retrieved from the Azraq wetland, Jordan. The pollen sequence provides evidence for a relatively stable wetland during the period of study until ca. AD 1400 when the wetland apparently declined as desert shrubland expanded. Springs continually supplied fresh water that maintained the shallow pools and marsh. In periods of increased winter precipitation, runoff from the surrounding wadis may have inundated the wetland and deposited silts and clays. During dryer episodes the influx of winter storm water would have been much less but the springs would have still provided water to the wetland and deposited peat. This is shown by the sequences of clay, silty and sandy clay loam, and peat in the core.  相似文献   

南四湖人工湿地建设与管理   总被引：1，自引：0，他引：1  

刘继凯  马慧 《湿地科学与管理》2010,6(2):37-39

采用生态滞留塘+多级表面流湿地系统的工艺方案建设南四湖人工湿地,使出水水质基本达到《地表水环境质量标准》Ⅲ类水质要求。利用人工湿地的生态经济价值,采取市场化运营的模式,探索"以湿养湿,以收养管"的管理机制,使南四湖人工湿地既能保障南水北调安全顺利进行,又能自身循环发展,取得"保水创收"的双赢效果。  相似文献   

Using an integrated model to track the fate and transport of suspended solids and heavy metals in the tidal wetlands     

Chou-ping YANG  Wu-seng LUNG  Jan-tai KUO  Jihn-sung LAI  Yu-min WANG  Chih-hung HSU 《国际泥沙研究》2012,27(2):201-212

An integrated two-dimensional depth-average numerical model was developed to simulate hydrodynamics and to track the fate and transport of contaminants in the Erh-Chung Flood Way wetland in northem Tai...  相似文献   

Effect of submerged aquatic vegetation on turbulence induced by an oscillating grid   总被引：1，自引：0，他引：1  

Dolors Pujol  Jordi ColomerTeresa Serra  Xavier Casamitjana 《Continental Shelf Research》2010

In wetlands wind-induced turbulence significantly affects the bottom boundary, and the interaction between turbulence and plant canopies is therefore particularly important. The aim of this study is to advance understanding of the impact of this interaction in submerged aquatic vegetation (SAV)¹ on vertical mixing in a fluid dominated by turbulence. Wind-generated turbulence was simulated in the laboratory using an oscillating grid. We quantify the vertical distribution of turbulent kinetic energy (TKE)² above and within different types of vegetation, measured by an acoustic Doppler velocimeter. Experimental conditions are analysed in two canopy models (rigid and semi-rigid) with seven solid plant fractions (SPFs)³, three stem diameters (d)⁴ and three oscillation grid frequencies (f)⁵ and four natural SAVs (Cladium mariscus, Potamogeton nodosus, Myriophyllum verticillatum and Ruppia maritima).  相似文献   

基于无人机和卫星遥感影像的升金湖草滩植被地上生物量反演     

高燕  梁泽毓  王彪  吴艳兰  刘诗雨 《湖泊科学》2019,31(2):517-528

湿地植被地上生物量是衡量湿地生态系统健康状况的重要指标,对于珍稀水禽越冬繁殖、全球碳循环、生态净化具有重要意义,是生态学与遥感解译的研究热点之一.针对于地上生物量的测算,卫星遥感数据覆盖范围广但其空间分辨率较低,无人机遥感数据空间分辨率高但采集范围小,同时受湿地面积、观测系统及外界环境等条件的影响,使得遥感影像地上生物量反演更加复杂和困难.本研究基于无人机和高分一号数据对升金湖草滩植被地上生物量反演进行研究,结合升金湖保护区4个样区无人机可见光影像与相应样区实测样本数据,建立地上生物量与可见光波段、多种可见光植被指数的线性、幂函数、多项式、对数回归模型,并通过可决系数（R²）、平均绝对误差（MAE）和均方根误差（RMSE）对模型进行精度评价,选择最优模型对无人机影像进行地上生物量反演;通过可见光波段反演得到的生物量,与高分一号WFV归一化差分植被指数（Normalized Difference Vegetation Index,NDVI）影像相结合进行回归建模,获取整个升金湖草滩植被地上生物量分布.结果表明,利用无人机红光波段建立的多项式方程对地上生物量反演有着最高模拟精度,R²=0.86、预测精度MAE=111.33 g/m²、RMSE=145.42 g/m²,且红光波段生物量反演方法得到的结果与实际生物量分布一致性较高,高分一号WFV NDVI与无人机反演生物量构建的多项式模型为最优模型,R²为0.91.本研究利用无人机和高分一号数据进行生物量反演研究,整合多源遥感数据优点,以获取更加丰富和准确的信息,进而提高地上生物量反演精度,为湿地监测和湿地恢复管理提供数据和技术支撑,具有重要研究意义和应用价值.  相似文献   

土壤动物对鄱阳湖湿地冬季凋落物分解过程的影响   总被引：1，自引：0，他引：1  

肖玲  马燕天  甘志伟  蔡润发  李卓琳  葛刚  吴兰 《湖泊科学》2020,32(2):395-405

为了研究湿地土壤动物对凋落物分解速率以及对土壤养分归还的影响,于2017年11月份在鄱阳湖湿地收集苔草(Carex cinerascens)、南荻(Triarrhena lutarioriparia)和芦苇(Phragmites australis) 3种植物的凋落物,利用凋落物袋法开展原位的模拟实验研究中使用了网孔大小分别为4.5 mm(大)和0.1 mm(小)的分解袋来对比分析土壤动物的影响结果表明:不同物种之间凋落物分解速率有差异,苔草的分解速率显著大于南荻和芦苇,南荻与芦苇的分解速率差异不明显;凋落物的分解速率与凋落物总有机碳和总氮的积累量(NAI_(TOC)/NAI_(TN))呈负相关,与残余凋落物质量呈负相关,与凋落物总磷含量呈正相关;凋落物总氮含量在不同物种凋落物中差异明显,表现为苔草芦苇南荻,并且与分解速率的大小关系相对应,因此高氮植物凋落物的分解速率较快;土壤动物能够提高分解速率,促进凋落物营养元素的释放,进而调节凋落物中C、N、P元素向土壤养分库的归还过程本研究将为湿地生态系统的营养元素循环研究提供科学数据.  相似文献