湿地蓄水量动态SD仿真研究--以三江平原沼泽湿地为例   总被引：1，自引：0，他引：1  

刘振乾  段舜山  李爱芬  徐宁  张珍萍  徐景亮 《地理与地理信息科学》2004,20(1):54-56

在沼泽湿地水循环系统分析基础上,根据系统动力学方法和原理,探讨湿地蓄水量动态仿真的方法、步骤和过程;以三江平原湿地生态实验站沼泽湿地为例,通过系统分析、函数建立、程序编写等过程建立了沼泽湿地蓄水量动态仿真模型,对模型反复检验和调试,直到获得较好的仿真效果;通过1997、1998、1999连续三年湿地水位变化实测与仿真结果的对比显示,仿真效果较好。  相似文献   

Experimental hydrological forcing to illustrate water flow processes of a subarctic ladder fen peatland          下载免费PDF全文

Colin P. R. McCarter  Jonathan S. Price 《水文研究》2017,31(8):1578-1589

Large peatland complexes dominate the landscape of the James Bay Lowland in subarctic Ontario, Canada. However, there is not a thorough understanding of the hydrological processes occurring in these important systems, particularly how ladder fens connect large domed bogs to the aquatic ecosystems that drain the peatland complex. Ladder fens consist of a pool‐rib topography where flow downgradient is controlled by the peat ribs. Within the ribs, low‐lying preferential flow paths typically enhance the transmission of water, whereas the elevated ridge microforms impede water flow to downgradient aquatic ecosystems. To assess the hydrological connectivity, we study the role of the water table, peat transmissivity, and microtopography of a small ladder fen for 3 summers (2013–2015) in the James Bay Lowland. The system was manipulated with a sustained hydrological forcing (water addition) to the upslope boundary of the fen during 2014 (38 m³/day) and 2015 (30 m³/day). There was an exponential increase in transmissivity towards the peat surface due to extremely high‐hydraulic conductivities within the upper few centimeters of the peat deposit. At the maximum water table, the saturated hydraulic conductivity of the 0.1 m layer of peat below the water table varied depending on peat microtopography (preferential flow paths = 42–598 m/day and ridges = 16–52 m/day), resulting in high‐hydrological connectivity periods. Furthermore, during 2015, there was an abnormally large amount of precipitation (300 mm vs. long‐term average ~ 100 mm) that resulted in complete surface water connectivity of the site. This caused rapid movement of water from the head of system to the outlet (~15 hr) and runoff ratios >1, compared to low‐water table periods (runoff ratio ~ 0.05). This study highlights the profound importance of the transmissivity–water table feedback mechanism in ladder fens, on controlling the water retention and drainage of large peatland complexes.  相似文献   

A natural experiment suggests little direct temperature forcing of the peatland palaeoclimate record          下载免费PDF全文

RICHARD J. PAYNE 《第四纪科学杂志》2014,29(6):509-514

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福建省前峰硫-多金属矿矿床特征及几个成因问题的讨论     

卢林 《化工矿产地质》1997,19(2):115-121

福建省前峰硫 多金属矿的形成具明显的层控特征。矿体赋存于上石碳统─下二叠统船山组及栖霞组灰岩中，成矿作用是多期叠加的、复杂的。在与生物礁有关的沉积阶段，生物吸附提供了主要硫源，后期热液改造对沉积成矿作用有着继承性，区域动力变质热液及其派生的分泌、分异成矿热液，以及与岩浆有关的热液多期次参与矿床的变质改造，而这些热液活动均与政和 大埔深大断裂有关。  相似文献   

刺参呼吸树的超微结构观察与研究     

刘晓云  包振民  范瑞青  谭金山  高澜 《海洋科学》2005,29(12):25-30

用光镜、扫描电镜和透射电镜观察研究健康刺参（Apostichopus japonicus）呼吸树的形态结构,并观察研究濒死刺参呼吸树的异常,结果显示：刺参呼吸树由外向内依次为体腔上皮、肌层、血腔、内皮细胞和中央腔。体腔上皮细胞游离面有长而不规则的微绒毛,细胞上部吞饮小泡丰富,细胞中常见吞噬体。内皮细胞表面有各种形状的细胞突起,细胞顶浆分泌活跃,细胞内质膜小泡丰富。体腔上皮细胞和内皮细胞中丰富的吞饮小泡和质膜小泡提示这两种细胞具有吸收功能。体腔上皮和内皮下连续成层的基膜围戍呼吸树中封闭的血腔。内皮层与内皮基膜构成呼吸树的呼吸膜,由泄殖腔进入呼吸树中央腔的海水和呼吸树血腔中的血液经此气一血屏障进行气体交换,完成呼吸作用。体腔上皮与上皮下基膜构成体腔液一血液屏障,刺参的体腔液与呼吸树血腔中的血液经此屏障进行物质交换。呼吸树还在渗透压调节和代谢产物排泄中起作用。在濒死刺参的呼吸树中,纤毛虫大量积聚在中央腔中并附着在内皮层上,导致呼吸作用不能正常进行,这可能是当养殖水体恶化时造成刺参患病并死亡的重要原因之一。  相似文献   

哈泥贫营养泥炭沼泽毛壁泥炭藓种群密度制约初探   总被引：1，自引：0，他引：1  

孙强  卜兆君  王升忠  孟祥军 《湿地科学》2005,3(2):116-120

在哈泥贫营养沼泽,研究了毛壁泥炭藓(Sphagnumimbricatum)种群的密度制约规律,结果表明,种群出生率、死亡率和增长率均表现为负密度制约;随初始密度的增加,种群出生率和增长率下降,死亡率增加;分株高度和生物量及其分配无严格的密度制约规律。毛壁泥炭藓种群密度制约规律的特殊性与复杂性与其特殊的生物学特性有关。保水合作与光资源竞争的权衡是决定种群数量特征对密度变化响应的主要原因。  相似文献   

Controls on accumulation of anomalously thick coals: Implications for sequence stratigraphic analysis     

Shuai Wang  Longyi Shao  Dongdong Wang  Jason Hilton  Biao Guo  Jing Lu 《Sedimentology》2020,67(2):991-1013

Coal seams preserve high-resolution records of ancient terrestrial water table (base level) fluctuations in ancient peat accumulations, but little is known about base level change in anomalously thick coal seams. Using the Early Cretaceous 91 m anomalously thick No. 6 coal (lignite) seam in the Erlian Basin (north-east China) as a case study, the origin and evolution of peat accumulation in a continental faulted basin is revealed by sedimentological, sequence stratigraphic and coal petrological analyses. The lignite is dominated by huminite, indicating oxygen-deficient and waterlogged conditions in the precursor mire. Four types of key sequence stratigraphic surfaces are recognized, including paludification, terrestrialization, accommodation-reversal and give-up transgressive surfaces. Vertically, the No. 6 coal seam consists of fourteen superimposed wetting-up and drying-up cycles separated by key sequence stratigraphic surfaces, with each of these cycles having a mean duration of about 156 to 173 kyr. In a high accommodation peat swamp system, the wetting-up cycles are generally characterized by an upward increase in mineral matter and inertodetrinite and an upward decrease in huminite with the paludification surface as their base and the give-up transgressive surface or accommodation-reversal surface as their top, representing a trend of upward-increasing accommodation. In contrast, the drying-up cycles are generally characterized by an upward decrease in mineral matter and inertodetrinite and an upward increase in huminite, with the terrestrialization surface as their base and the accommodation-reversal surface as their top, representing a trend of upward-decreasing accommodation. A multi-phase mire stacking model for accumulation of the coal seam is proposed based on high-frequency accommodation cycles and the stratigraphic relationships between coal and clastic sediments. High-frequency accommodation cycles in the coal are closely related to water table fluctuations in the precursor mires and are driven by high-frequency climate via changes in the intensity and seasonality of precipitation in a relatively stable subsidence regime. Recognition that the No. 6 coal seam is composed of multiple stacked mires has implications for studies addressing palaeoclimatic inferences and genesis of anomalously thick coals seams.  相似文献   

中国沼泽研究的几个问题   总被引：2，自引：0，他引：2  

马学慧 《湖泊科学》1993,5(1):78-84

中国沼泽研究已有三十多年历史。三十年来先后对主要沼泽分布区进行综合考察,获得了丰富的研究成果,填补了沼泽学科的空白。今后的沼泽研究应从下列几方面入手:(1)在查明资源的基础上,建立我国沼泽的分类体系和信息系统;(2)加强沼泽基础理论研究,逐步完善中国沼泽学科体系;(3)进行沼泽综合开发模式和泥炭利用的研究;(4)建立若干沼泽生态站和保护区,保护部分有价值的沼泽地。  相似文献   

A high‐resolution record of mire development and climatic change spanning the Late‐glacial–Holocene boundary at Church Moss,Davenham (Cheshire,England)     

P. D. M. Hughes  H. K. Kenward  A. R. Hall  F. D. Large 《第四纪科学杂志》2000,15(7):697-724

Excavations of deposits filling a closed basin within glacial drift at Church Moss, Davenham, near Northwich (Cheshire, England) revealed a sequence of Late‐glacial and Early Holocene sediments. Analyses of pollen and plant and invertebrate macrofossils were undertaken, together with loss‐on‐ignition analyses and a programme of AMS radiocarbon dating, to provide a record of changing biostratigraphy and climatic and ecological regimes. The infilling of features identified as frost‐cracks in the till flooring the basin gave remains that reflected conditions of extreme cold towards the end of the Devensian. The pollen record from a 3.5 m sequence of peat towards the deepest part of the basin, supported by radiocarbon dates, shows that organic deposition was initiated during the Late‐glacial Interstadial and continued into the early part of the Holocene. There was some evidence for a cool episode during the interstadial, with amelioration prior to the rapid onset of the tundra conditions of the Loch Lomond Stadial. Following the stadial, amelioration was rapid. There was evidence from both central and marginal sequences for a mosaic of fen dominated by sedges and often also mosses, with short‐lived small pools through much of the succession. Change to terrestrial conditions proceeded intermittently, probably as a result of subsidence caused by solution of underlying salt‐bearing strata. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

Spring water table depth mediates within-site variation of soil temperature in groundwater-fed mires     

Michal Horsák  Veronika Horsáková  Marek Polášek  Radovan Coufal  Petra Hájková  Michal Hájek 《水文研究》2021,35(7):e14293

Groundwater-dependent ecosystems represent globally rare edaphic islands of scattered distribution, often forming areas of regionally unique environmental conditions. A stable groundwater supply is a key parameter defining their ecological specificity, promoting also soil thermal buffering. Still, a limited number of studies dealt with the importance of water temperature in mire ecosystems and virtually no data exist on within-site variation in the temperature buffer effect. Three temperature dataloggers, placed in patches potentially differing in groundwater supply, were installed in each of 19 Western Carpathian spring mire sites from May 2019 to July 2020. Spring source plots statistically differed in water temperature parameters from the plots located towards the spring mire margin, which did not significantly differ from one another. At the majority of sites, the temperature values changed gradually from spring source to mire margins, fitting the pattern expected in the groundwater temperature buffering scenario. Dataloggers placed in the spring sources were the most distinctive from the others in thermal buffering parameters in conditional principal component analysis. The difference between the spring source and its margin was on average 3.25 °C for 95th percentile of the recorded water temperature data points (i.e. warm extremes) and 1.91 °C for 5th percentile (i.e. cold extremes). This suggests that if the temperature at spring source area is considered, thermal buffering within a site may mitigate mainly warm extremes. Thus, our data may provide an important baseline for predictions of possibly upcoming changes in spring mire hydrology caused by climate change. Both warming and precipitation decrease can give rise to the loss or substantial reduction of buffering effect if the contrasting parameters now recorded at the central part shift to those found towards the margins of groundwater-fed areas.  相似文献