Winter Decomposition of Emergent Macrophytes Affects Water Quality under Ice in a Temperate Shallow Lake
Winter Decomposition of Emergent Macrophytes Affects Water Quality under Ice in a Temperate Shallow Lake
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DOI：
10.3390/w12092640
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发表时间：
2020-09
期刊：
影响因子：
3.4
通讯作者：
Yuanyun Wei;Manyin Zhang;L. Cui;Xu Pan;Weiwei Liu;Wei Li;Yinru Lei
中科院分区：
文献类型：
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作者：
Yuanyun Wei;Manyin Zhang;L. Cui;Xu Pan;Weiwei Liu;Wei Li;Yinru Lei
挺水植物的分解现在被认为是浅水湖泊的内部营养源。温带湖泊在冬季通常会经历季节性的冰盖覆盖，但冰下挺水植物分解对水质的影响很少被研究。在衡水湖，采用室内培养试验研究了两种常见挺水植物（香蒲和芦苇）的冬季分解及其对水质的影响。模拟湖泊冰制度的中生态系统在冬季进行了120天的培养，并进行了处理，有和没有植物材料的添加。通过溶解氧（DO）、溶解有机碳（DOC）、总氮（TN）、总磷（TP）、铵态氮（NH 4-N）和硝态氮（NO3-N）监测水质。我们发现，这两个物种都显着分解在冬季和大部分的质量损失发生在前10天的分解时，水面的围隔已经冻结。植物材料淹没后，DO浓度迅速下降至接近零的值。在培养结束时，DOC，TN和NO3-N的浓度与植物材料的添加中围生态系统显着高于初始浓度。与此相反，DOC，TN，TP，NO3-N，NH 4-N的浓度在没有植物材料添加的围隔中等于或小于初始浓度。研究表明，挺水植物的冬季分解对冰下水质产生了持续整个冬季的负面影响。
Decomposition of emergent macrophytes is now recognized as an internal nutrient source for shallow lakes. Temperate lakes always experience seasonal ice cover in winter, but the influences of emergent macrophytes decomposition on water quality have rarely been examined under ice. Here, we conducted an incubation experiment to investigate winter decomposition of two common emergent macrophytes species (Typha orientalis and Phragmites australis) and its influences on water quality in the Hengshui Lake, North China. Mesocosms simulating a lake ice regime were incubated in the field for 120 days in winter and were treated with and without plant material addition. Water quality was monitored through dissolved oxygen (DO), dissolved organic carbon (DOC), total nitrogen (TN), total phosphorus (TP), ammonium nitrogen (NH4-N), and nitrate nitrogen (NO3-N). We found that both species were significantly decomposed in winter and that the majority of mass loss occurred in the first 10 days of decomposition when the water surface of mesocosms were already frozen. The concentrations of DO rapidly dropped to values close to zero after plant material submergence. At the end of incubation, the concentrations of DOC, TN, and NO3-N in the mesocosms with plant material addition were significantly higher than initial concentrations. In contrast, the concentrations of DOC, TN, TP, NO3-N, and NH4-N in the mesocosms without plant material addition were equal to or less than initial concentrations. Our research suggests that winter decomposition of emergent macrophytes produces negative influences on water quality under ice that lasts for the whole winter.