Microorganisms and Organic Matter Decomposition
Microorganisms and Organic Matter Decomposition
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微生物和有机物分解
DOI：
10.1007/978-1-4612-1652-0_6
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
K. Suberkropp
中科院分区：
文献类型：
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作者：
K. Suberkropp
·森林河流生态系统通常被认为是异养的。它们的大部分能量依赖于来自河岸带的外来有机物的输入。这些有机物是碎屑食物链的基础，在这个食物链中，异养微生物(真菌、细菌和原生动物)将有机物分解并转化为可供较高营养水平的生物使用的能量。·溶解有机物(DOM)和颗粒有机物(POM)都在溪流中分解。POM的分解或分解，如落叶和木材，是淋溶、微生物矿化和碎裂的结果。与落叶分解相关的主要微生物是真菌，特别是水生丝状真菌，这是一种适应流水的生态真菌群。这些真菌产生能软化(浸渍)落叶的胞外酶。真菌种类对无脊椎动物的适口性各不相同。可口真菌的生长和活动使树叶成为这些动物更好的食物来源。切碎无脊椎动物(碎纸机)。真菌定植导致的叶碎屑食物质量的改善似乎是真菌生物量和真菌降解酶浓度增加的结果。这些酶将叶组织转化为更易同化的食物来源，并可能继续在碎纸机的消化道中发挥作用。·树叶崩解率受内部因素和外部环境因素的影响，例如凋落物质量(氮、木质素、单宁含量)和外部环境因素(溪水中的营养物质浓度、温度、碎纸机的存在、pH、水流速度和氧气利用率)。·木材的分解速度通常比树叶凋落物的分解速度慢。尽管人们对溪流中涉及木材腐烂的生物和过程知之甚少，但木质基质上的微生物活动是显著的。·细小颗粒和溶解有机物的分解由细菌主导。从溶解的有机物通过细菌流向原生动物和滤食无脊椎动物的能量流动代表了微生物循环--这是一条在森林溪流中营养再生发挥重要作用的营养途径。·真菌的生物量和产量在粗颗粒有机物(CPOM)(如树叶)上占主导地位。随着有机物粒径的减小，引入生物量和细菌产量增加，而真菌产量下降。
• Forested stream ecosystems are generally considered heterotrophic. They depend on inputs of allochthonous organic matter from the riparian zone for most of their energy. This organic matter is the base of the detrital food web in which heterotrophic microorganisms (fungi, bacteria, and protozoa) decompose and transform organic matter into energy available to organisms at higher trophic levels.• Both dissolved organic matter (DOM) and particulate organic matter (POM) are decomposed in streams. The decomposition, or breakdown, of POM such as leaf litter and wood occurs as a result of leaching, microbial mineralization, and fragmentation. The predominant microorganisms associated with the breakdown of leaf litter are fungi, in particular, aquatic hyphomycetes, an ecological group of fungi that are adapted to flowing waters. These fungi produce extracellular enzymes that soften (macerate) leaf litter. Fungal species vary in their palatability to invertebrate detritivores. The growth and activity of palatable fungi make leaf litter a better food source for these animals. shredding invertebrates (shredders). The improvement in food quality of leaf detritus as a result of fungal colonization appears to be the result of increased concentrations of fungal biomass and fungal degradative enzymes. These enzymes convert leaf tissue into a more assimilable food source and may continue to act in the digestive tract of the shredder.• Rates of leaf breakdown are affected both by internal factors, such as litter quality (nitrogen, lignin, tannin content) and external environmental factors (nutrient concentrations in stream water, temperature, presence of shredders, pH, current velocity, and oxygen availability).• Wood typically breaks down at slower rates than leaf litter. Although less is known about the organisms and processes involved in wood decay in streams, microbial activity on woody substrates is significant.• Decomposition of fine particulate and dissolved organic matter is dominated by bacteria. The flow of energy from dissolved organic matter through bacteria to protozoa and filter feeding invertebrates represents the microbial loop-a trophic pathway that plays an important role in nutrient regeneration in forested streams.• Biomass and production of fungi predominate over that of bacteria on coarse particulate organic matter (CPOM) such as leaves. As the particle size of the organic matter decreases, Introduction biomass and production of bacteria increases as that of fungi declines.
WATANABE,YASUNORI.：海洋微生物食物网。
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