Whole-stream metabolism in nutrient-poor calcareous streams on Öland, Sweden
Whole-stream metabolism in nutrient-poor calcareous streams on Öland, Sweden
复制标题
瑞典厄兰岛营养贫乏的钙质溪流的全溪流代谢
DOI：
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发表时间：
2015
期刊：
影响因子：
2.4
通讯作者：
K. Sand‐Jensen
中科院分区：
文献类型：
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作者：
A. B. Alnoee;T. Riis;M. Andersen;A. Baattrup‐Pedersen;K. Sand‐Jensen
我们研究了瑞典厄兰岛三个源头非森林河流河段的整个河流代谢，以便描述这个不寻常的生态系统的新陈代谢特征，并将其与欧洲西北部的其他河流生态系统进行比较。初级总产量 (GPP) 普遍较低（<4 g O2 m−2 d−1），最低的 GPP 记录在石灰岩阿尔瓦平原的最上游、排水较薄的土壤的浅河段。在这里，完全淹没的陆地植物可以解释基流的全部初级生产。由于农业影响，生态系统呼吸（ER）增加了数倍，导致下游的异养溪流条件以及光合作用对光的需求高于呼吸。在两个营养最贫乏的地点发现每日 GPP 和 ER 之间存在密切关系。温度校正的瞬时 ER 率在夜间开始时最高，但在同一河段的夜间结束时下降，表明暗呼吸耗尽了光合产物并受到有机底物的限制。对欧洲西北部开放河流的大规模比较显示出 1:1 的关系，表明夏季（4 月至 8 月）每日 GPP 和 ER 之间存在紧密联系，但冬季则不然。这项研究扩大了 GPP 和 ER 测量范围，将营养贫乏的欧洲西北部河流纳入其中，从而增加了对这一农业高度受影响地区河流代谢的了解。它还记录了溪流中 GPP 和 ER 之间的密切关系，从春季和夏季的营养极度贫乏到营养中等丰富的条件。
We studied whole-stream metabolism in three headwater non-forested stream reaches on the island of Öland, Sweden in order to characterize the metabolism of this unusual ecosystem and to compare it with other stream ecosystems in NW Europe. Gross primary production (GPP) was generally low (<4 g O2 m−2 d−1) with the lowest GPP recorded in the most upstream, shallow reach draining the thin soils of the limestone Alvar plains. Here, completely flooded terrestrial plants could account for the whole primary production at baseflow. Ecosystem respiration (ER) increased several fold with agricultural impact, resulting in heterotrophic stream conditions downstream and higher light requirements for photosynthesis to outweigh respiration. A strong relationship between daily GPP and ER was found at the two most nutrient-poor sites. Temperature corrected instantaneous ER rate was highest in the beginning of the night, but decreased at the end of the night at the same reaches, indicating that dark respiration depleted photosynthetic products and became limited by organic substrates. The broad-scale comparison of open NW European streams showed a 1:1 relationship, indicating a tight link between daily GPP and ER during summer (April–August) but not during winter. This study has extended the range of GPP and ER measurements to include nutrient-poor NW European streams, thereby increasing the knowledge on stream metabolism in this, otherwise, highly agricultural impacted region. It also documented a strong relationship between GPP and ER in streams, ranging from extremely nutrient poor to moderately nutrient rich conditions during spring and summer.