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1.
蚯蚓如何影响土壤有机碳的固持是土壤生态学的关键科学问题之一。蚯蚓能同时促进土壤有机碳分解和稳定,这种两面作用带来的不确定性被研究者称为\"蚯蚓困境\"。研究证据和新兴的\"土壤微生物碳泵\"概念模型表明土壤微生物残留物是土壤有机质的主要贡献者。为系统了解蚯蚓对土壤微生物残留物的影响与可能的机制,研究分析和总结了已有的国内外蚯蚓与微生物残留物（氨基糖）的相关研究成果,表明：（1）过往的研究忽略了蚯蚓对微生物残留物的影响,导致这一方向的研究严重滞后;（2）蚯蚓对土壤微生物残留物影响的方向和大小仍有很大的不确定性,可供量化分析其驱动机制的研究还很缺乏。研究尝试将蚯蚓整合到\"土壤微生物碳泵\"概念框架中,分析蚯蚓影响土壤微生物残留物3个方面的可能机制,即：（1）改变土壤微生物量、群落结构,（2）改变微生物生理特性,（3）改变土壤团聚体结构等,影响土壤有机碳的积累。同时,本文提出了未来相关研究的6个重点方向,包括：（1）蚯蚓对微生物的选择性取食,（2）肠道介导的微生物\"涨落\"现象,（3）蚯蚓对矿质结合有机物的\"破坏\"与\"重组\",（4）蚯蚓引起的\"激发\"和\"续埋\"效应,（5）多生态型相互作用,（6）全球变化背景下的蚯蚓生态学等,以期为进一步揭示蚯蚓-微生物相互作用影响土壤有机碳累积与稳定性的机制提供参考。 相似文献
2.
Bingbing Han;Yanzhong Yao;Yini Wang;Xiaoxuan Su;Lihua Ma;Xinping Chen;Zhaolei Li; 《Global Ecology and Biogeography》2024,33(1):151-161
The accumulation of microbial necromass carbon has gained increasing attention due to its slow decomposition. However, it remains unclear what induces the accumulation of microbial necromass carbon via reiterated community turnover on large spatial scales. This study explores the characteristics of soil necromass carbon accumulation in terrestrial ecosystems. 相似文献
3.
Microbe-mediated carbon transformation plays an important role in soil carbon sequestration, which is considered to be one of the key strategies to achieve carbon neutrality in the long term. Assessing the efficiency of microbial necromass accumulation relative to plant carbon input or microbial respiration will help to identify ways to promote soil carbon sequestration from an ecosystem perspective. 相似文献
4.
Madhav Prakash Thakur Martina Herrmann Katja Steinauer Saskia Rennoch Simone Cesarz Nico Eisenhauer 《Ecology and evolution》2015,5(19):4300-4314
Soil food webs comprise a multitude of trophic interactions that can affect the composition and productivity of plant communities. Belowground predators feeding on microbial grazers like Collembola could decelerate nutrient mineralization by reducing microbial turnover in the soil, which in turn could negatively influence plant growth. However, empirical evidences for the ecological significance of belowground predators on nutrient cycling and plant communities are scarce. Here, we manipulated predator density (Hypoaspis aculeifer: predatory mite) with equal densities of three Collembola species as a prey in four functionally dissimilar plant communities in experimental microcosms: grass monoculture (Poa pratensis), herb monoculture (Rumex acetosa), legume monoculture (Trifolium pratense), and all three species as a mixed plant community. Density manipulation of predators allowed us to test for density‐mediated effects of belowground predators on Collembola and lower trophic groups. We hypothesized that predator density will reduce Collembola population causing a decrease in nutrient mineralization and hence detrimentally affect plant growth. First, we found a density‐dependent population change in predators, that is, an increase in low‐density treatments, but a decrease in high‐density treatments. Second, prey suppression was lower at high predator density, which caused a shift in the soil microbial community by increasing the fungal: bacterial biomass ratio, and an increase of nitrification rates, particularly in legume monocultures. Despite the increase in nutrient mineralization, legume monocultures performed worse at high predator density. Further, individual grass shoot biomass decreased in monocultures, while it increased in mixed plant communities with increasing predator density, which coincided with elevated soil N uptake by grasses. As a consequence, high predator density significantly increased plant complementarity effects indicating a decrease in interspecific plant competition. These results highlight that belowground predators can relax interspecific plant competition by increasing nutrient mineralization through their density‐dependent cascading effects on detritivore and soil microbial communities. 相似文献
5.
张萌;程瑞梅;沈雅飞;陈天;李璟;曾立雄;雷蕾;肖文发 《应用生态学报》2025,36(1):141-151
微生物源碳和植物源碳的积累共同决定了土壤有机碳库的稳定。为探究绿肥覆盖下土壤团聚体不同来源有机碳的积累特征及其相对贡献,本研究在柑橘园中设置野外定位控制试验,以清耕处理为对照,分析光叶苕子覆盖对土壤大团聚体(2～8 mm)、小团聚体(0.25～2 mm)以及微团聚体(<0.25 mm)不同来源有机碳的影响,量化了不同来源有机碳对土壤团聚体总有机碳的贡献,明确了不同来源有机碳积累的驱动因素。结果表明: 1)光叶苕子覆盖增加了土壤团聚体真菌残体碳、微生物残体碳含量以及二者对土壤团聚体总有机碳的贡献,其中,微团聚体真菌残体碳、微生物残体碳含量增加幅度最大,分别为76.7%、70.2%;光叶苕子覆盖还提高了土壤团聚体真菌残体碳与细菌残体碳的比值,且比值的变化范围为4.58～4.66,说明真菌残体碳含量较高,主导了微生物残体碳的积累。2)光叶苕子覆盖降低了大团聚体的总木质素酚含量及其对总有机碳的贡献,但显著增加了微团聚体总木质素酚含量,而对微团聚体总木质素酚对总有机碳的贡献无显著影响。3)土壤有机碳和微生物生物量碳是微生物残体碳的重要影响因素,亮氨酸氨基肽酶和交换性钙离子含量的增加提高了微生物残体碳对总有机碳的贡献;络合态铁氧化物含量是提高微团聚体总木质素酚对总有机碳贡献的重要因子。综上所述,光叶苕子覆盖下真菌残体碳主导了土壤团聚体微生物残体碳的积累,大团聚体中植物源碳可能转化为微生物源碳储存在土壤中,微生物源碳将主导土壤团聚体有机碳的变化。 相似文献
6.
土壤微生物残体碳在有机碳(SOC)形成过程中具有重要作用。为了量化评估不同菌根类型森林土壤微生物残体碳对SOC的贡献,对80篇已发表的文献进行了Meta分析,明确了丛枝菌根(AM)和外生菌根(EM)树种占优势的森林土壤细菌和真菌残体碳含量及其在SOC中的占比差异。结果表明,EM森林表层土壤微生物、真菌、细菌残体碳含量及其对SOC的贡献均显著高于AM森林;而EM和AM森林底层土壤中三者含量及其占SOC比例差异均不显著。两种森林表层土壤微生物残体碳含量均显著高于底层土壤,且表层土壤真菌残体碳含量均显著高于细菌残体碳含量。在表层土壤中,EM森林土壤微生物残体碳含量变化范围为0.08—89.17 g/kg,其中,真菌和细菌残体碳平均含量分别为12.75 g/kg和3.98 g/kg,对SOC的平均贡献分别为27.78%和10.68%;AM森林土壤微生物残体碳含量变化范围为0.54—71.64 g/kg,其中,真菌和细菌残体碳平均含量为6.42 g/kg和2.31 g/kg,占SOC比例分别为22.65%和8.84%。环境因子调控着土壤微生物残体碳的积累,SOC、总氮(TN)和年平均温度(MAT)是影响AM和EM森林土壤微生物残体碳的重要因素,EM森林中较高的SOC和TN含量及较低的MAT有利于微生物残体碳的积累,而AM森林中较高的pH和MAT促进了微生物残体的分解。 相似文献
7.
Stable carbon and nitrogen isotope ratios (δ13C and δ15N) are used to study the trophic structure of food web in the Yellow Sea and East China Sea ecosystem. The trophic continuum
of pelagic food web from phytoplankton to top preyer was elementarily established, and a trophic structure diagram in the
Yellow Sea and East China Sea was outlined in combination with carbon isotopic data of benthic organisms, which is basically
consistent with and makes some improvements on the simplified Yellow Sea food web and the trophic structure diagram drawn
based on the biomass of main resource population during 1985–1986. This result indicates that the stable isotope method is
a potential useful means for further studying the complete marine food web trophic continuum from viruses to top predators
and food web stability. 相似文献
8.
根据2011年春季和秋季在胶州湾进行的渔业资源综合调查,应用稳定同位素示踪技术,分析了胶州湾主要渔业生物的碳、氮稳定同位素比值(δ13C,δ15N),并计算其营养级,进而构建胶州湾食物网的连续营养谱。分析的生物种类包括浮游植物、浮游动物、大型无脊椎动物和鱼类,其生物量之和占总渔获量的95%。结果表明,胶州湾食物网的δ13C值范围是-25.63‰—-17.16‰,跨度为8.47‰,平均值为(-19.42±1.80)‰;δ15N值范围是4.15‰—14.11‰,跨度为9.96‰,平均值为(11.98±1.77)‰。胶州湾食物网中的主要生物种类可以划分为4个营养组群,即初级生产者、初级消费者、次级消费者以及顶级捕食者。δ15N值分析显示,胶州湾主要生物种类的营养级范围是1.10—4.03。与文献中基于胃含物分析计算的营养级相比较,37个种类中有29种的营养级分析结果基本一致(在0.5个营养级的误差范围之内)。因此,氮稳定同位素法是一种研究水生生态系统食物网营养位置的有效方法。其中,有8种鱼类的营养级与历史文献相比有所下降,分析方法的不同可能是原因之一,此外,这些鱼种摄食饵料生物营养级的下降也是导致其营养级降低的另一个主要原因。根据营养级计算的结果,构建了胶州湾食物网的连续营养谱,胶州湾食物网中,绝大多数生物种类都属于初级和中级肉食性种类。 相似文献
9.
10.
Ranran Zhou Yuan Liu Jennifer A. J. Dungait Amit Kumar Jinsong Wang Lisa K. Tiemann Fusuo Zhang Yakov Kuzyakov Jing Tian 《Global Change Biology》2023,29(7):1998-2014
Microbial necromass is a large and persistent component of soil organic carbon (SOC), especially under croplands. The effects of cropland management on microbial necromass accumulation and its contribution to SOC have been measured in individual studies but have not yet been summarized on the global scale. We conducted a meta-analysis of 481-paired measurements from cropland soils to examine the management effects on microbial necromass and identify the optimal conditions for its accumulation. Nitrogen fertilization increased total microbial necromass C by 12%, cover crops by 14%, no or reduced tillage (NT/RT) by 20%, manure by 21%, and straw amendment by 21%. Microbial necromass accumulation was independent of biochar addition. NT/RT and straw amendment increased fungal necromass and its contribution to SOC more than bacterial necromass. Manure increased bacterial necromass higher than fungal, leading to decreased ratio of fungal-to-bacterial necromass. Greater microbial necromass increases after straw amendments were common under semi-arid and in cool climates in soils with pH <8, and were proportional to the amount of straw input. In contrast, NT/RT increased microbial necromass mainly under warm and humid climates. Manure application increased microbial necromass irrespective of soil properties and climate. Management effects were especially strong when applied during medium (3–10 years) to long (10+ years) periods to soils with larger initial SOC contents, but were absent in sandy soils. Close positive links between microbial biomass, necromass and SOC indicate the important role of stabilized microbial products for C accrual. Microbial necromass contribution to SOC increment (accumulation efficiency) under NT/RT, cover crops, manure and straw amendment ranged from 45% to 52%, which was 9%–16% larger than under N fertilization. In summary, long-term cropland management increases SOC by enhancing microbial necromass accumulation, and optimizing microbial necromass accumulation and its contribution to SOC sequestration requires site-specific management. 相似文献
11.
CAI Deling LI Hongyan TANG Qisheng & SUN Yao . Key Laboratory of Marine Sedimentology & Environment Geology SOA First Institute of Oceanography State Oceanic Administration Qingdao China . Ocean University of China Qingdao China . Yellow Sea Fisheries Research Institute Chinese Academy of Fishery Sciences Qingdao China 《中国科学：生命科学英文版》2005,48(6):531-539
The determination of trophic level for the biology in a marine ecosystem is very important as alteration of its structure and function may be reflected in the tro-phic level of component species. A change in trophic level indicates variation in an organism’s feeding bi-ology or in the pathway of energy flow from primary producers to the consumer. The gut content analysis is a traditional method for studying trophodynamics of food web in marine ecosystems. Species composition and amounts in al… 相似文献
12.
Romana Limberger Julia Birtel Hannes Peter Núria Cataln Daniel da Silva Farias Rebecca J. Best Jakob Brodersen Helmut Bürgmann Blake Matthews 《Oikos》2019,128(3):430-440
The fate of dissolved organic carbon (DOC) is partly determined by its availability to microbial degradation. Organisms at upper trophic levels could influence the bioavailability of DOC via cascading effects on primary producers and bacteria. Here we experimentally tested whether the presence of fish in aquatic food webs can indirectly affect the composition of the DOC pool. We found that fish had strong positive effects on phytoplankton biomass that affected the dynamics of DOC composition. Specifically, fish increased protein‐like, algae‐derived DOC mid‐experiment, concurrent with the strongest fish‐induced increase in phytoplankton biomass. Fish also increased bacterial abundance, altered the community composition and diversity of bacteria, and temporarily increased DOC compounds with fluorescence properties indicative of microbially‐reprocessed organic matter. Overall, our experiment revealed that fish can positively influence the substrate (algae‐produced DOC) and the key players (bacteria) of the microbial carbon pump. Consequently, fish could contribute to carbon sequestration by stimulating both the production of bioavailable DOC and the microbial degradation of bioavailable to persistent DOC. We propose this as a novel mechanism whereby the loss of predators from global ecosystems could alter carbon cycling. 相似文献
13.
稳定同位素作为一种天然的示踪物,应用十分广泛,其在水域生态学中的应用也日益受到重视。生物同位素组成总是与其食物同位素组成相一致,能随食物的改变而相应地发生改变,是生物生存状况的理想指示物,为水域生态系统食物网结构与功能、物质流与能量流的研究提供了有力的技术支撑。在综评稳定同位素技术原理与方法的基础上,较为详细地对其应用于水域生态研究的理论基础与进展进行了总结。该方法的应用以水域中生产者同位素组成差异为前提,主要涉及确定食物来源、食物的贡献比例、营养级的确定、食物网结构的构建及鱼类等水生生物的洄游及迁移路线等方面,这些研究对了解生态系统的动态变化与外界环境对其影响具有重要意义。并对我国此类研究的前景和存在问题进行了探讨。 相似文献
14.
基于稳定同位素技术的海州湾海洋牧场食物网基础及营养结构的季节性变化 总被引：2，自引：0，他引：2
基于稳定同位素技术对2015年春季海州湾海洋牧场海域采集的中小型生物消费者,包括鱼类、虾类、蟹类、头足类、螺类和双壳类等与其潜在碳源样品进行分析,利用IsoSource模型计算该海域消费者碳源贡献率,并对2014年夏季生物学样品与2015年春季样品比较,分析食物网营养结构的季节性变化,根据稳定同位素测定结果绘制二维双标图,计算出6种营养结构的量化指标.结果表明: 2015年春季海州湾海洋牧场海域消费者的δ13C值范围为-18.9‰～-17.1‰,3种潜在碳源[浮游植物、悬浮颗粒有机物(POM)、沉积物(SOM)]的δ13C值范围为-18.1‰～-23.4‰,根据模型计算得出浮游植物对消费者的平均碳源贡献最大,为80.8%,其余依次为SOM和POM,分别为10.8%和8.4%.2014年夏季生物样品与2015年春季样品的δ13C值存在显著差异,而δ15N值无显著性差异;6种量化指标表明群落营养结构存在季节性差异, 2014年夏季的δ13C比值范围(CR)、总面积(TA)、平均最邻近距离(NND)和平均最邻近距离标准差(SDNND)均大于2015年春季,δ15N比值范围(NR)和平均离心距离(CD)无明显变化,夏季群落营养结构冗余度小于春季,且食源多样性水平高于春季,存在季节差异. 相似文献
15.
为探讨水胺硫磷对小鼠骨髓细胞的遗传毒性及其机制,以昆明种小鼠为受试动物,水胺硫磷按0.11、0.54、1.08、2.16 mg·kg-1剂量水平灌胃染毒2次,30 h后取骨髓细胞,采用慧星实验方法测定骨髓细胞DNA的损伤;采用Fenton反应法和黄嘌呤氧化酶法分别测定骨髓细胞的抑制羟自由基能力和抗超氧阴离子能力,同时对DNA断裂指标和这两种抑制氧自由基能力的活性进行回归分析。结果显示,各浓度组小鼠骨髓细胞尾距和Olive尾距均显著高于对照组(P0.05),且随水胺硫磷暴露浓度的增加而升高,呈明显的剂量-效应关系。0.11 mg·kg-1低浓度组小鼠骨髓细胞的抗超氧阴离子能力被显著诱导(P0.05),但抑制羟自由基能力未被显著诱导;0.54、1.08、2.16 mg·kg-1各浓度处理组,抗超氧阴离子和抑制羟自由基能力均被显著诱导(P0.01)。骨髓细胞尾距和Olive尾距均随着抑制羟自由基能力和抗超氧阴离子能力的升高而增加,且呈线性关系(P0.01)。上述结果表明,水胺硫磷具有较强的急性遗传毒性,其毒理作用机制可能是通过诱导小鼠骨髓细胞产生氧自由基从而造成对DNA氧化损伤。 相似文献
16.
Wiackowski Krzysztof Ventelä Anne-Mari Moilanen Marianne Saarikari Vesa Vuorio Kristiina Sarvala Jouko 《Hydrobiologia》2001,443(1-3):43-57
A mesocosm experiment in 24 enclosures (6 m3) started at the end of June 1996 in a highly eutrophic shallow lake, Lake Köyliönjärvi (SW Finland). The original factorial design with nutrient, fish and macrophyte treatments was lost due to strong winds causing leakages. However, after the walls were made leak-proof again on July 11, the planktonic communities developed in divergent ways. On July 31 there was a tenfold variation in total crustacean biomass among the enclosures and the lake (40.2–417.5 g C l–1), and chlorophyll a varied from 9.5 to 67.0 g l–1. Here, the single-day data on the 25 planktonic communities is analysed by means of correlation and factor analysis in order to identify factors controlling the protozoans, with particular emphasis on ciliates. The data set comprised: total phosphorus, nitrogen, chlorophyll, bacteria, autotrophic picoplankton, heterotrophic flagellates, abundance and species composition of ciliates, phytoplankton and metazooplankton. The results indicate that although the total ciliate abundance (ranging from 16.2 to 95.0 ind l–1) was controlled by food resources, the observed differences in ciliate community structure could be attributed partly to differential predation by metazooplankton. The effect of Daphnia cucullata, the dominant daphnid cladoceran, was stronger than that of other metazoans. 相似文献
17.
Marianne V. Moore Bart T. De Stasio Kristin N. Huizenga Eugene A. Silow 《Freshwater Biology》2019,64(1):138-151
- Pelagic copepods often couple the classical and microbial food webs by feeding on microzooplankton (e.g. ciliates) in oligotrophic aquatic systems, and this consumption can trigger trophic cascades within the microbial food web. Consumption of mixotrophic microzooplankton, which are both autotrophic and heterotrophic within the same individual, is of particular interest because of its influence on carbon transfer efficiency within aquatic food webs.
- In Lake Baikal, Siberia, it is unknown how carbon from a well‐developed microbial food web present during summer stratification moves into higher trophic levels within the classical food web.
- We conducted in situ experiments in August 2015 to test the hypotheses that: (a) the lake's dominant endemic copepod (Epischura baikalensis), previously assumed to be an herbivore feeding on diatoms, connects the microbial and classical food webs by ingesting ciliates; and (b) this feeding initiates top‐down effects within the microbial food web.
- Our results supported these hypotheses. E. baikalensis individuals consumed on average 101–161 ciliates per day, obtaining 96%–98% of their ingested carbon from ciliates and the remainder from small diatoms. Clearly, E. baikalensis is omnivorous, and it is probably channelling more primary production from both the microbial food web and the classical food web of Lake Baikal to higher trophic levels than any other pelagic consumer.
- Most ciliates consumed were a mixotrophic oligotrich and such taxa are often abundant in summer in other oligotrophic lakes. Consumption of these mixotrophs is likely to boost substantially the transfer efficiency of biomass to higher trophic levels with potential implications for fish production, but this has seldom been investigated in oligotrophic lakes.
- Feeding of E. baikalensis initiated a three‐link predatory cascade which reduced the abundance of ciliates and elevated growth rates of heterotrophic nanoflagellates but did not affect abundance or growth rates of autotrophic picoplankton. This demonstration of a potential trophic cascade in Lake Baikal indicates that investigations at larger spatial–temporal scales are needed to identify the conditions promoting or precluding trophic cascades in this lake.
18.
Judith Prommer Tom W. N. Walker Wolfgang Wanek Judith Braun David Zezula Yuntao Hu Florian Hofhansl Andreas Richter 《Global Change Biology》2020,26(2):669-681
Species‐rich plant communities have been shown to be more productive and to exhibit increased long‐term soil organic carbon (SOC) storage. Soil microorganisms are central to the conversion of plant organic matter into SOC, yet the relationship between plant diversity, soil microbial growth, turnover as well as carbon use efficiency (CUE) and SOC accumulation is unknown. As heterotrophic soil microbes are primarily carbon limited, it is important to understand how they respond to increased plant‐derived carbon inputs at higher plant species richness (PSR). We used the long‐term grassland biodiversity experiment in Jena, Germany, to examine how microbial physiology responds to changes in plant diversity and how this affects SOC content. The Jena Experiment considers different numbers of species (1–60), functional groups (1–4) as well as functional identity (small herbs, tall herbs, grasses, and legumes). We found that PSR accelerated microbial growth and turnover and increased microbial biomass and necromass. PSR also accelerated microbial respiration, but this effect was less strong than for microbial growth. In contrast, PSR did not affect microbial CUE or biomass‐specific respiration. Structural equation models revealed that PSR had direct positive effects on root biomass, and thereby on microbial growth and microbial biomass carbon. Finally, PSR increased SOC content via its positive influence on microbial biomass carbon. We suggest that PSR favors faster rates of microbial growth and turnover, likely due to greater plant productivity, resulting in higher amounts of microbial biomass and necromass that translate into the observed increase in SOC. We thus identify the microbial mechanism linking species‐rich plant communities to a carbon cycle process of importance to Earth's climate system. 相似文献
19.
基于稳定同位素的湿地食物源判定和食物网构建研究进展 总被引：1，自引：0，他引：1
湿地生物营养动力学是湿地生态系统结构和功能评价研究的基础.碳、氮稳定同位素作为识别营养关系的方法,已在湿地生态系统食物来源、组成和食物链传递研究中得到广泛运用.本文系统综述了稳定同位素食物贡献度计算模型和营养级确定的基本方法和理论;讨论了动物营养分馏值和基线的选择依据;概括了湿地生态系统典型食物源及其稳定同位素变化特征;总结了草食、杂食和肉食等不同营养级动物的食物来源.指出了稳定同位素在湿地食物源溯源和食物网研究中的不足;基于国内外研究现状和发展趋势及需求,展望了未来同位素技术在湿地食物网生态学研究中的运用前景和研究重点,提出需要加强稳定同位素营养分馏和基线的影响因素、样品处理和保存方式研究以及胃含物、分子标记物和多元素同位素结合分析. 相似文献
20.
Xiangyin Ni Shu Liao Siyi Tan Yan Peng Dingyi Wang Kai Yue Fuzhong Wu Yusheng Yang 《Global Ecology and Biogeography》2020,29(10):1829-1839