Nutrient additions to mitigate for loss of Pacific salmon: consequences for stream biofilm and nutrient dynamics
Nutrient additions to mitigate for loss of Pacific salmon: consequences for stream biofilm and nutrient dynamics
复制标题
添加营养物质以减轻太平洋鲑鱼的损失：对溪流生物膜和营养动态的影响
DOI：
--
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
M. Wipfli
中科院分区：
文献类型：
--
作者：
Amy M. Marcarelli;C. Baxter;M. Wipfli
旨在补充太平洋鲑鱼数量减少或丧失的溪流的养分和有机物输入的缓解活动通常预先假定，将鲑鱼的营养物质转移到鱼类（溯河产卵的和/或留栖的）的重要途径是通过生物膜吸收养分以及随后自下而上刺激生物膜的产生，而在鲑鱼回报下降的许多生态系统中，生物膜的养分受到限制。我们的目标是量化营养物掺入和生物膜动态的程度，这些动态是支撑这一间接途径的，以响应三年来向爱达荷州中部溪流 500 米河段实验添加鲑鱼尸体和颗粒状鱼粉（又称鲑鱼尸体类似物）。在处理后的一个月内，生物膜直立作物增加了 2-8 倍，并吸收了海洋来源的营养物质（使用 15N 和 13C 测量），但这些反应并没有逐年持续。生物膜在处理前受到氮 (N) 限制，并且在类似物中仍保持氮限制，但在屠体处理的河段中不受氮 (N) 限制。尽管存在这些生物膜反应，在处理后的一个月中，总氮负荷等于添加到处理河段的氮的 33-47%，氮螺旋测量表明，添加的氮中多达 20%，但更有可能的是 2-3% 被微生物吸收。设计营养添加的生物学和成本效益策略需要了解河流微生物吸收营养的速率以及输出营养的下游距离。
Mitigation activities designed to supplement nutrient and organic matter inputs to streams experiencing decline or loss of Pacific salmon typically presuppose that an important pathway by which salmon nutrients are moved to fish (anadromous and/or resident) is via nutrient incorporation by biofilms and subsequent bottom-up stimulation of biofilm production, which is nutrient-limited in many ecosystems where salmon returns have declined. Our objective was to quantify the magnitude of nutrient incorporation and biofilm dynamics that underpin this indirect pathway in response to experimental additions of salmon carcasses and pelletized fish meal (a.k.a., salmon carcass analogs) to 500-m reaches of central Idaho streams over three years. Biofilm standing crops increased 2–8-fold and incorporated marine-derived nutrients (measured using 15N and 13C) in the month following treatment, but these responses did not persist year-to-year. Biofilms were nitrogen (N) limited before treatments, and remained N limited in analog, but not carcass-treated reaches. Despite these biofilm responses, in the month following treatment total N load was equal to 33–47% of the N added to the treated reaches, and N spiraling measurements suggested that as much as 20%, but more likely 2–3% of added N was taken up by microbes. Design of biologically and cost-effective strategies for nutrient addition will require understanding the rates at which stream microbes take up nutrients and the downstream distance traveled by exported nutrients.