Spring to summer nitrogen level in a brackish lake is higher in abundant snowmelt years: Correlation and causation.
Spring to summer nitrogen level in a brackish lake is higher in abundant snowmelt years: Correlation and causation.
复制标题
咸水湖春季至夏季的氮水平在融雪丰富的年份较高：相关性和因果关系。
DOI：
10.1002/jeq2.20033
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发表时间：
2020
影响因子：
2.4
通讯作者：
H. Tanji
中科院分区：
文献类型：
--
作者：
Kazunori Shizuka;N. Maie;Masayasu Nagasaki;W. Kakino;H. Tanji
富营养化是许多具有农业分水岭的咸水湖泊所关注的问题。由于全球气候变化，预计多雪地区的降雪量将减少。本研究的目的是评估下游咸水湖的营养盐浓度的融雪流入的变化的影响。在小川原湖，一个半咸水湖在积雪覆盖的农业区的日本，我们研究了流入的河流流量（D/C）在春季和总氮（TN）和总磷（TP）浓度之间的关系在混合层的湖泊（[TNmix ]和[TPmix ]，分别）使用29年的监测数据。此外，我们评估了D/C和湖泊营养盐浓度之间的因果关系。4月份D/C（D/CAr）的年际变化较大，占混合层体积的7%~ 31%。从随后的4月到9月，D/CAr和[TNmix ]之间观察到显着的正相关。在一个年度的基础上，49%的年际变化的平均[TNmix ]在随后的4月至9月解释的年际变化的D/CAr。因此，D/CAr可以作为一个简单的指数[TNmix ]在随后的春季到夏季。值得注意的是，从4月到9月的D/CAr和[TNmix ]之间的关系表明是因果关系的统计因果推断。增加D/CAr的常见气候条件（即，一个寒冷的冬天，降水量高）被发现驱动其他地球化学过程，增加[TNmix ]在随后的春天到夏天。
Eutrophication is an issue of concern in many brackish lakes with an agricultural watershed. The amount of snowfall in snowy areas is anticipated to decline because of global climate change. The aim of this study was to assess the impact of changes in the inflow of snowmelt on the nutrient concentrations of a downstream brackish lake. In Lake Ogawara, a brackish lake in a snow-covered agricultural area of Japan, we examined the relationships between inflowing river discharge (D/C) during spring and total nitrogen (TN) and total phosphorus (TP) concentrations in the mixolimnion of the lake ([TNmix ] and [TPmix ], respectively) using 29 yr of monitoring data. In addition, we assessed the causal relationship between the D/C and the lake nutrient concentrations. There was large year-to-year variation in D/C during April (D/CApr ), which accounted for 7-31% of the mixolimnion volume. Significant positive correlations were observed between D/CApr and [TNmix ] from the ensuing April to September. On an annual basis, 49% of the interannual variation of the mean [TNmix ] during the ensuing April to September was explained by the interannual variation of D/CApr . Therefore, D/CApr could be useful as a simple index to [TNmix ] in the ensuing spring to summer. It is notable that the relationships between D/CApr and [TNmix ] from April to September was indicated to be acausal by statistical causal inference. Common climate conditions that increase D/CApr (i.e., a cold winter with a high level of precipitation) were found to drive other biogeochemical processes that increased [TNmix ] during the ensuing spring to summer.
影响因子：
3.8
作者：
R. Hatano;T. Nagumo;Hiroshi Hata;Kanta Kuramochi
通讯作者：
R. Hatano;T. Nagumo;Hiroshi Hata;Kanta Kuramochi