The sensitivity of water chemistry to climate in a forested, nitrogen-saturated catchment recovering from acidification
The sensitivity of water chemistry to climate in a forested, nitrogen-saturated catchment recovering from acidification
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从酸化恢复的森林覆盖、氮饱和的流域中水化学对气候的敏感性
DOI：
10.1016/j.ecolind.2015.12.014
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发表时间：
2016
影响因子：
6.9
通讯作者：
J. Turek
中科院分区：
文献类型：
--
作者：
J. Kopáček;J. Hejzlar;J. Kaňa;P. Porcal;J. Turek
1998年至2014年，在捷克共和国Čertovo湖的氮饱和山林集水区-湖泊系统中测量了主要离子和营养物质的通量。自20世纪80年代末以来，由于硫酸盐（SO 42 −）沉积减少了90%，硝酸盐（NO3−）对强酸阴离子池的贡献和溶解有机碳（DOC）的沥滤增加，该湖已迅速从大气酸化中恢复过来。因此，目前支流中的盐基阳离子、磷（P）、总有机氮（TON）、离子铝（Ali）和有机结合铝（Alo）的浓度主要受NO3−和DOC沥滤的影响。尽管持续了25年的恢复，切尔托沃流域仍然是质子（H+）的净来源，在流域面积的基础上产生44 mmol m− 2 yr − 1 H+（相当于35 μmol L− 1浓度）。沉积的无机氮在集水区的平均保留率为20%，铵的消耗（51 mmol m− 2 yr −1）和NO3−的净产生（28 mol m− 2 yr −1）是陆地产生H+的主要过程。相比之下，从土壤中释放的SO 42 −对陆地H+产生的重要性不断下降，在研究期间平均为47 mmol m− 2 yr − 1。湖泊中的地球化学过程使进入的酸度降低了40%，中和了23 μmol L−1H+（即，225 mmol m− 2 yr − 1（基于湖泊面积）。反硝化作用和光化学和微生物分解DOC是最重要的在湖H+消耗过程（50和39%，分别），而水解的阿里（从支流和光化学释放的Alo）是占主导地位的在湖H+生成过程。由于水化学和H+平衡在集水湖泊系统的趋势越来越多地与NO3−和DOC淋溶的变化有关，它们对气候相关因素（干旱，径流量增加）和森林破坏变得敏感，这些因素显着改变了这些阴离子的淋溶。在研究期间，从Čertovo流域的NO3−（伴随着Aliand基阳离子）的出口增加发生在干燥炎热的夏季，森林破坏后，在冬季径流升高。增加DOC出口，由于减少酸沉降的进一步升高，在年径流量较高（特别是在事件与侧流），并伴随着P，TON，和Alleaching。与气候有关的过程，最初“只”混淆化学趋势的沃茨恢复酸化，可能很快成为主要变量控制水的组成在N-饱和集水区。
Fluxes of major ions and nutrients were measured in the N-saturated mountain forest catchment-lake system of Čertovo Lake (Czech Republic) from 1998 to 2014. The lake has been rapidly recovering from atmospheric acidification due to a 90% decrease in sulphate (SO42−) deposition since the late 1980s and nitrate (NO3−) contribution to the pool of strong acid anion and leaching of dissolved organic carbon (DOC) have increased. Present concentrations of base cations, phosphorus (P), total organic N (TON), and ionic (Ali) and organically bound (Alo) aluminium in tributaries are thus predominantly governed by NO3−and DOC leaching. Despite a continuing recovery lasting 25 years, the Čertovo catchment is still a net source of protons (H+), producing 44 mmol m−2yr−1H+on a catchment-area basis (corresponding to 35 μmol L−1on a concentration basis). Retention of the deposited inorganic N in the catchment averages 20%, and ammonium consumption (51 mmol m−2yr−1) and net NO3−production (28 mol m−2yr−1) are together the dominant terrestrial H+generating processes. In contrast, the importance of SO42−release from the soils on terrestrial H+production is continuously decreasing, with an average of 47 mmol m−2yr−1during the study. The in-lake biogeochemical processes reduce the incoming acidity by ∼40%, neutralizing 23 μmol L−1H+(i.e., 225 mmol m−2yr−1on a lake-area basis). Denitrification and photochemical and microbial decomposition of DOC are the most important in-lake H+consuming processes (50 and 39%, respectively), while hydrolysis of Ali(from tributaries and photochemically liberated from Alo) is the dominant in-lake H+generating process. Because the trends in water chemistry and H+balance in the catchment-lake system are increasingly related to variability in NO3−and DOC leaching, they have become sensitive to climate-related factors (drought, elevated runoff) and forest damage that significantly modify the leaching of these anions. During the study period, increased exports of NO3−(accompanied by Aliand base cations) from the Čertovo catchment occurred after a dry and hot summer, after forest damage, and during elevated winter runoff. Increasing DOC export due to decreasing acid deposition was further elevated during years with higher runoff (and especially during events with lateral flow), and was accompanied by P, TON, and Aloleaching. The climate-related processes, which originally “only” confounded chemical trends in waters recovering from acidification, may soon become the dominant variables controlling water composition in N-saturated catchments.