毛果苔草湿地植物营养元素分布及其相关性

研究生物与环境中化学因子之间的相互作用过程 ,主要是指化学物质在生态系统中的运移、转化及归趋与效应。化学物质包括营养物质、污染物质和在生物与环境之间、生物与生物之间起媒介作用的次生代谢物质[1] 。对植物不同组织营养成分的季节性变化研究多集中于叶子 ,但对其他部分的研究则较少[10 ] ,分解过程并不是完全始于凋落物到达地面 ,在凋落前就受到渗滤、裂解和真菌的作用[12 ] ;对枯落物中的有机物质和营养物质浓度的了解可以预测枯落物的分解速率[11] 。目前 ,湿地的研究偏重于资源的开发与利用 ,而对湿地生态系统的生态过程的定位…     

广东省生态环境若干问题

在地球上,动物、植物、微生物等生物集团与其周围环境,即水、土、气、光、温等因素之间,由于长期的自然选择和自然进化,逐渐形成了一种相互联系、相互依赖和相互制约的关系。它们之间不断地进行物质循环和能量交换而自成体系,这就是生态系统。森林、河流、农田、城市等,都是性质不同的生态系统。生态系统中各种生物种群(分为生产者——主要是绿色植物、消费者——主要是各种动物、还原者——主要是微生物)物质和能量的运动,遵循一定的规律和维持相对稳定的状态;其物种和个体数量     

现代化经济建设与生态科学——试论当代生态学工作者的任务

宇宙空间是无限的,但适于人类生活和生物生存的生物圈则是有限的,它是个松散结构的大系统,其中包括许多类型的生物集团与无机环境结合而成的功能单元,即生态系统。在长期进化过程中,通过物质循环与能量交换,生物圈与生态系统之间建立了相互协调与补偿关系,并使生物圈及生态系统都具有一定限度的调节功能。人类对自然界的依存关系,以及自然界所形成的生态平衡是长期演化而形成的,人类亦参与和适应了此平衡过程。维持这种平衡的基础是有规律的物质循环和能量交換。此种质能流动则是通过     

东北高寒地区麦田土壤活性有机质和环境因素关系的灰色分析

土壤圈是地球各圈层物质循环和能量交换的枢纽,在土壤圈中的养分变化和生物结构变化对农业持续发展的影响起重要作用［６］。土壤有机质层是动态的生态系统。它是由植物、动物和微生物及其它环境因素共同作用而组成的物质和能量交换系统。其中土壤中有机质释放的具有生物活性的酶类也参与这一过程。这种作用与有机质的合成和分解密切相关,其作用集中表现在活性有机质的动态变化方面。所以土壤活性有机质可以表征土壤物质循环特征,也可用以评价土壤质量的优劣。有机质的生产和矿化过程是土壤中生物因素和非生物因素共同作用的结果。因此,…     

渤海生态通道模型初探

生态通道模式（Ｅｃｏｐａｔｈ Ｍｏｄｅｌ）是一种较为方便地研究生态系统结构,特别是水域生态系统结构的工具,它根据能量平衡原理,用线性齐次方程组描述生态系统中的生物组成和能量在各生物组成之间的流动过程,定量某些生态参数,如生物量、生产量／生物量、消耗量／生物量、营养级和生态营养效率（ＥＥ,Ｅｃｏｔｒｏｐｈｉｃ Ｅｆｆｉｃｉｅｎｃｙ）等,它能够给出能量在生态通道上的流动量,便于对生态２系统的特征和变化     

镁同位素在森林生态系统研究中的应用

镁元素是常量元素之一,也是生物维持生命活动的重要物质之一。含镁矿物的风化产物经河流输送到达海洋,并在此过程参与生态系统的物质循环,最终通过碳酸盐沉淀重新成岩,这一过程与全球的碳循环密切相关。近年来,随着非传统金属同位素体系的不断完善,以及MC-ICP-MS(多接收器电感耦合等离子质谱仪)的使用,镁同位素的测试精度与便利程度都有提升,镁同位素因为其广泛参与化学风化过程以及与生命活动密切相关,从而成为示踪表生环境中物质来源与各类生物地球化学过程的有效工具。因此,研究镁同位素在各类生态系统中的组成特征与分馏机理,可以帮助我们了解生态系统内发生的各类地球化学过程,进而探寻全球物质循环与气候变化规律。本文系统阐述了森林生态系统中各组分镁同位素的组成和分馏的影响因素,提出了目前森林生态系统研究存在的问题,并基于现有研究成果对未来森林生态系统中镁同位素的研究方向进行了探讨。     

樟子松固沙林动力效应的研究

在人工林生态系统中,植被与大气之间以湍流的形式不断地进行动量、热量和水分交换,交换过程与下垫面的某些空气动力特征有关。为确定植被与大气之间能量和物质的交换强     

灰色系统理论在种群增长建模中的应用

一、引言广义地讲,客观系统都是物质的系统,能量的系统。对于生物种群的增长来说,其本质是生物种群与环境之间进行物质的交换和能量的传递过程,所以生物种群系统也是广义的能量系统。作为能量系统,必有储能、放能、吸能等功能。具有这种功能的系统,一般都可用微分方程予以描述。生物种群的增长是反映生物与环境相适应,生物之间进行生存竞争的主要标志之一。它兼受自然因素、环境条件、营养状况的制约和影响,是各种不同性质的影响因素相互促进     

湿地生物连通性影响因素及测度方法研究进展

湿地是地球上最多样化和最具生产力的生态系统之一,但近年来由于人类活动的频繁干扰,自然环境以前所未有的速度变化,两者的协同作用导致湿地呈现破碎化趋势。湿地的退化、转化使得湿地生物连通性减弱。良好的湿地生物连通性有利于湿地生态系统服务功能的维持、生物多样性的保护以及生物对气候变化适应水平的提高。因此理解、评估和保护生物连通性对于湿地生态系统而言至关重要。综述了湿地生物连通性的定义、总结了生物连通发生与变化的四个相互作用因子,从结构连通性、功能连通性两个测定角度,论述动物、植物和微生物三类研究对象生物连通性的测度方法,最后从湿地生物连通的时空尺度,连通与物质循环的耦合关系,湿地生物连通性评估分析模型改进角度提出了未来的研究方向,从而确保湿地生物连通网络的完整有效。可为湿地生物多样性、湿地保护和管理提供新的思路。     

浅谈生态平衡

(一)什么是生态平衡生态平衡指在一定时间内,生态系统中生物和环境之间以及生物各种群之间相互制约、维持某种协调,并由于系统内在的调节机制而遵循动态平衡法则,使能量流动、物质循环和信息传递达到一种动态结构的相对稳定状态。一般说来,生态系统的发展过程与植物群落的正向演替过程是一致的,都是在一定的裸     

Development of natural conditions in constructed wetlands: Biological and chemical changes

The main objectives of this study were to determine the biogeochemical changes taking place in wetlands constructed on coal mine spoil, and to determine the rate at which these constructed wetlands would develop the ecological characteristics of natural wetlands. In 1992 a multicell wetland was constructed. The cells were lined with two coal mine spoil types and one topsoil. In 1993, the cells were planted with cattail (Typha latifolia), maidencane (Panicum hemitomon), pickerelweed (Pontederia lanceolota), and soft stem bulrush (Scirpus validus). Pickerelweed spread most rapidly followed by maidencane and bulrush. Cattail did not establish uniformly but spread in an irregular manner. There was no difference in plant establishment between the topsoil or the two mine spoils. The pH of the most acidic spoil increased by more than one unit after flooding. Organic matter content fluctuated in all three substrates from year to year. The concentration of the nutrient and metal elements increased after flooding. Extractable Al, Fe, and Mn increased more than other elements. The data presented here indicate that, except for organic matter accumulation, these constructed wetlands have taken on the botanical and biogeochemical characteristics of natural wetlands within 3–4 years.     

Abundant carbon substrates drive extremely high sulfate reduction rates and methane fluxes in Prairie Pothole Wetlands

Inland waters are increasingly recognized as critical sites of methane emissions to the atmosphere, but the biogeochemical reactions driving such fluxes are less well understood. The Prairie Pothole Region (PPR) of North America is one of the largest wetland complexes in the world, containing millions of small, shallow wetlands. The sediment pore waters of PPR wetlands contain some of the highest concentrations of dissolved organic carbon (DOC) and sulfur species ever recorded in terrestrial aquatic environments. Using a suite of geochemical and microbiological analyses, we measured the impact of sedimentary carbon and sulfur transformations in these wetlands on methane fluxes to the atmosphere. This research represents the first study of coupled geochemistry and microbiology within the PPR and demonstrates how the conversion of abundant labile DOC pools into methane results in some of the highest fluxes of this greenhouse gas to the atmosphere ever reported. Abundant DOC and sulfate additionally supported some of the highest sulfate reduction rates ever measured in terrestrial aquatic environments, which we infer to account for a large fraction of carbon mineralization in this system. Methane accumulations in zones of active sulfate reduction may be due to either the transport of free methane gas from deeper locations or the co‐occurrence of methanogenesis and sulfate reduction. If both respiratory processes are concurrent, any competitive inhibition of methanogenesis by sulfate‐reducing bacteria may be lessened by the presence of large labile DOC pools that yield noncompetitive substrates such as methanol. Our results reveal some of the underlying mechanisms that make PPR wetlands biogeochemical hotspots, which ultimately leads to their critical, but poorly recognized role in regional greenhouse gas emissions.     

红树林湿地硫酸盐还原菌的多样性及其参与驱动的元素耦合机制

红树林生态系统是热带和亚热带地区重要的滨海湿地,具有营养物质形态多样化和高效动态变化的特征,是驱动碳、氮、硫等元素循环的热区。硫酸盐还原菌(sulfate-reducing prokaryotes,SRPs)是地球最古老的微生物生命形式之一,在推动早期地球地质演化以及现代生物地球化学循环中发挥关键作用,但其在红树林湿地还缺乏全面深入研究。本文基于Genome Taxonomy Database中原核生物基因组的挖掘,系统总结了硫酸盐还原菌的类群,梳理了近年来国内外红树林中硫酸盐还原菌的分布情况及影响其分布的因素,分析了硫酸盐还原菌在红树林生态系统的碳、氮、硫及铁等元素地球化学循环中的作用,并对硫酸盐还原菌未来的研究方向进行了展望,以期为深入研究硫酸盐还原菌参与驱动的元素生物地球化学循环及其耦合机制提供参考。     

Evaluation of commercial soil health tests using a medium-term cover crop experiment in a humid,temperate climate

Plant and Soil - Microbial-driven biogeochemical cycles of phosphorus (P) in wetlands subjected to global climate warming result in a downstream eutrophication risk. However, how warming influences...     

湿地氮素传输过程研究进展

综述了湿地氮素传输过程的研究进展。湿地氮素传输过程包括物理过程、化学过程和生物过程 ,与土壤、植物的发生、发育紧密联系在一起 ,并形成了空气 -水 -土 -生命系统中物质循环和能量流动的复杂网络。湿地硝态氮的淋失直接威胁着湿地地下水水质安全 ,N2 O源汇转变受土壤和水体等环境因子的制约 ,氨挥发则与水体 p H值密切相关排放。湿地氮素的化学转化过程是矿质养分供给和 N2 O产生的主要机制 ,受环境因子和人类活动干扰的影响 ;动力学模型可用于描述氮素的化学转化过程。湿地植物的吸收和累积以及微生物的分解过程是湿地氮素循环的重要环节。最后分析了当前国内外研究中存在的不足 ,并对未来研究的重点领域进行了展望     

Biogeochemical Constraints on the Ecological Rehabilitation of Wetland Vegetation in River Floodplains

The European policy for river management during peak discharge periods is currently changing from exclusion strategies (reinforcement of dykes) to allowing a more natural situation by creating more floodplain space to reduce water levels during peak discharges. In addition, water retention and water storage areas have been created. The new measures are generally being combined with nature development strategies. Up till now, however, ecological targets of broadscale floodplain wetland restoration including sedge marshes, species-rich floodplain forests and carrs, riparian mesotrophic grasslands and other biodiverse riverine ecosystems, have hardly developed in these areas. Most studies on the conditions needed for sustainable ecological development of floodplains have focused on hydrological and geomorphological rather than biogeochemical issues (including nutrient availability and limitation). There are, however, large differences in the composition of river water and groundwater and in sediment quality between rivers in densely populated areas and those in more pristine areas, which serve as a reference. It is very likely that these factors, in combination with heavily altered hydrological regimes and the narrow areas confined between the dykes on both sides of the rivers, impose major constraints on sustainable ecological development of riverine areas. Another issue is that existing wetlands are generally considered to be very appropriate for water retention and conservation, although recent research has shown that this may pose a serious threat to their biodiversity. The present paper reviews the biogeochemical constraints on the combination of floodplain rehabilitation, water conservation and the conservation and development of wetlands. It is concluded that biogeochemical problems (mainly related to eutrophication) predominantly arise in less dynamic parts of the river system, to which the flood-pulse concept applies less. Sound knowledge of the biogeochemical processes involved will contribute to greater efficiency and a better prediction of the opportunities for restoration and development of riverine wetlands. This information can be directly applied in nature management, water management, policy-making and consultancy.     

Application of Reference Data for Assessing and Restoring Headwater Ecosystems

Attributes of 25 headwater streams and their associated wetlands were quantitatively sampled in the inner coastal plain of eastern North Carolina. Data from these sites were used to construct and test one functional assessment model (biogeochemical cycling) using the hydrogeomorphic (HGM) approach. Of the 25 sites sampled, 16 unaltered sites were used to establish standards against which field indicators could be compared (indexed). Nine altered sites were used to examine the sensitivity of the model to assess the types of alterations typically inflicted upon headwater ecosystems in eastern North Carolina: channelization, logging, construction of cross-floodplain ditches to shunt water directly from uplands to the main stream channel, and conversion of stream floodplains and buffer zones to cropland. Of 30 field indicators measured that potentially could be used to model alterations to hydrologic regime and biomass stocks, we found six were robust in assessing conditions related to biogeochemical cycling. Hydrologic indicators used in the model included: (1) presence/absence of channelization, (2) presence/absence of cross-floodplain ditches, and (3) a measure of buffer condition (using width and quality). Biomass indicators included: (4) total basal area of trees, (5) percent litter cover, and (6) volume of coarse woody debris. Our preliminary biogeochemical cycling model using these six variables was sensitive to alterations in nine altered sites and to a suite of hypothetical restorations of the most altered site. However, in order to improve accuracy of our preliminary model, it should be validated with studies designed to measure how alterations of various types and magnitudes affect biogeochemical processes.     

The development of patterned mosaic landscapes: an overview

The articles in this special issue review what is known about the development of wetlands in landscapes and of patterns in various kinds of wetlands around the world with an emphasis on wetlands with treed patches (tree islands) like the Okavango Delta and the Everglades. Wetlands with treed patches have much in common with their terrestrial counterparts in arid regions. Both are mosaic landscapes in which the patches of trees are distributed in a non-random fashion in a matrix of herbaceous vegetation. In these landscapes, the treed patches are both biogeochemical and biodiversity hotspots. They are biogeochemical hotspots because treed patches preferentially acquire nutrients and other limited resources, like water in arid regions. They are biodiversity hotspots because treed patches are habitats with environmental and structural characteristics very different from those of the herbaceous matrix in which they are found. Consequently, treed patches attract and support populations of many plant and animal species that otherwise would not be found in the area. Studies and simulation models of arid mosaic landscapes have generated a number of hypotheses about the structure and functions of mosaic landscapes, most of which have yet to be tested, especially in wetland mosaic landscapes.     

Bioactive chemicals and biological—biochemical activities and their functions in rhizospheres of wetland plants

Wetland soils provide anoxia-tolerant plants with access to ample light, water, and nutrients. Intense competition, involving chemical strategies, ensues among the plants. The roots of wetland plants are prime targets for root-eating pests, and the wetland rhizosphere is an ideal environment for many other organisms and communities because it provides water, oxygen, organic food, and physical protection. Consequently, the rhizosphere of wetland plants is densely populated by many specialized organisms, which considerably influence its biogeochemical functioning. The roots protect themselves against pests and control their rhizosphere organisms by bioactive chemicals, which often also have medicinal properties. Anaerobic metabolites, alkaloids, phenolics, terpenoids, and steroids are bioactive chemicals abundant in roots and rhizospheres in wetlands. Bioactivities include allelopathy, growth regulation, extraorganismal enzymatic activities, metal manipulation by phytosiderophores and phytochelatines, various pest-control effects, and poisoning. Complex biological-biochemical interactions among roots, rhizosphere organisms, and the rhizosphere solution determine the overall biogeochemical processes in the wetland rhizosphere and in the vegetated wetlands. To comprehend how wetlands really function, it is necessary to understand these interactions. Such understanding requires further research.     

Advancing the use of minirhizotrons in wetlands

Background

Wetlands store a substantial amount of carbon (C) in deep soil organic matter deposits, and play an important role in global fluxes of carbon dioxide and methane. Fine roots (i.e., ephemeral roots that are active in water and nutrient uptake) are recognized as important components of biogeochemical cycles in nutrient-limited wetland ecosystems. However, quantification of fine-root dynamics in wetlands has generally been limited to destructive approaches, possibly because of methodological difficulties associated with the unique environmental, soil, and plant community characteristics of these systems. Non-destructive minirhizotron technology has rarely been used in wetland ecosystems.

Scope

Our goal was to develop a consensus on, and a methodological framework for, the appropriate installation and use of minirhizotron technology in wetland ecosystems. Here, we discuss a number of potential solutions for the challenges associated with the deployment of minirhizotron technology in wetlands, including minirhizotron installation and anchorage, capture and analysis of minirhizotron images, and upscaling of minirhizotron data for analysis of biogeochemical pools and parameterization of land surface models.

Conclusions

The appropriate use of minirhizotron technology to examine relatively understudied fine-root dynamics in wetlands will advance our knowledge of ecosystem C and nutrient cycling in these globally important ecosystems.