Comparing field and laboratory breakdown rates of coarse particulate organic matter: Sediment dynamics mask the impacts of dissolved nutrients on CPOM mass loss in streams
Comparing field and laboratory breakdown rates of coarse particulate organic matter: Sediment dynamics mask the impacts of dissolved nutrients on CPOM mass loss in streams
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比较粗颗粒有机物的现场和实验室分解率：沉积物动力学掩盖了溶解养分对溪流中 CPOM 质量损失的影响
DOI：
10.1007/s00027-007-0932-z
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发表时间：
2007
期刊：
影响因子：
2.4
通讯作者：
K. Küsel
中科院分区：
文献类型：
--
作者：
Bernd Spänhoff;C. Augspurger;K. Küsel
微生物分解落叶和木质残体的刺激溶解养分的增加。因此，粗颗粒有机物（CPOM）的分解率可能是有用的评估河流生态系统的富营养化的影响。本研究的目的是比较分解率的落叶，牙签，树枝在高地流（Ilm，图林根州，德国）和它的两个支流，以确定最好的CPOM类型调查中度富营养化的影响CPOM质量损失。2004年12月至2005年5月，在4个取样点共暴露了160个细网眼袋（1毫米）（无脊椎动物切碎机除外）。同时，在标准化条件下，将CPOM在充满来自4个研究中心的环境溪流水的水族箱中孵育。在水族箱中，牙签显示出增加溶解的营养物质浓度的治疗，而没有显着的影响，山毛榉叶和树枝的分解率增加的故障率检测。在外地，物理破碎，由于高速和泥沙运输在3个网站为主的砾石加速叶片分解率。在桑迪支流，袋所覆盖的沉积砂，可能会降低叶片分解率，尽管高营养浓度。质量损失的木质残体（牙签和树枝）的砾石流和掩埋在砂流磨损的影响，但在较小程度上比落叶。因此，通过移动沉积物对CPOM的磨损和研磨的物理破碎可以掩盖营养物质对分解率的影响。由于快速的分解速度和抗破碎性，牙签可以用作评估低至中等流速河流水质的工具。
Microbial decomposition of leaf litter and woody debris is stimulated by an increase in dissolved nutrients. Thus, breakdown rates of coarse particulate organic matter (CPOM) might be useful for assessing the impact of eutrophication on stream ecosystems. The objective of this study was to compare breakdown rates of leaf litter, toothpicks, and twigs in an upland stream (Ilm, Thuringia, Germany) and two of its tributaries to determine the best CPOM type for investigating moderate eutrophication effects on CPOM mass loss. A total of 160 fine-mesh bags (1 mm) that excluded invertebrate shredders were exposed at 4 sampling sites from December 2004 to May 2005. Simultaneously, CPOM was incubated in aquaria filled with ambient stream water from each of the 4 study sites under standardized conditions. In aquaria, toothpicks showed increasing breakdown rates in treatments with increasing dissolved nutrient concentrations, whereas no significant effects on breakdown rates of beech leaves and twigs were detected. In the field, physical fragmentation due to high velocities and sediment transport at 3 sites dominated by gravels accelerated leaf breakdown rates. In the sandy tributary, bags were covered by deposited sand that might have decreased leaf breakdown rates despite high nutrient concentrations. Mass loss of the woody debris (toothpicks and twigs) was affected by abrasion in the gravel streams and by burying in the sand stream, but to a lesser extent than leaf litter. Thus, physical fragmentation by abrasion and grinding of CPOM by moving sediment can mask the effect of nutrients on breakdown rates. Because of a fast breakdown rate and resistance to fragmentation, toothpicks could be used as a tool to assess water quality in streams with low to intermediate flow velocities.