Patterns of nitrogen and sulfur accumulation and retention in ombrotrophic bogs, eastern Canada
Patterns of nitrogen and sulfur accumulation and retention in ombrotrophic bogs, eastern Canada
复制标题
加拿大东部弱营养沼泽中氮和硫的积累和保留模式
DOI：
10.1111/j.1365-2486.2004.00882.x
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发表时间：
2005
影响因子：
11.6
通讯作者：
P. Richard
中科院分区：
文献类型：
--
作者：
T. Moore;C. Blodau;J. Turunen;N. Roulet;P. Richard
氮(N)和硫(S)分别通过影响植物产量和泥炭分解速率以及氧化还原反应在泥炭地发挥着重要作用，泥炭地蕴藏着这两种元素的大量储量。利用泥炭N和S浓度、干体积密度和~(210)Pb测年方法，测定了加拿大东部23个富营养化沼泽中N和S 150年来的累积速率。N和S的平均浓度分别为0.80%和0.18%，总体上随剖面深度的增加而增加，N和S浓度之间存在着微弱但显著的相关性。N和S在过去50-150年间的累积速率分别为0.5~4.8 g N m−2 yr−1和0.1~0.9 g S m−2 yr−1。C、N和S的累积速率在50年、100年和150年之间存在显著但微弱的相关性。在过去的50年里，S的氮积累速率在丘陵和洼地之间几乎没有差异，而氮的积累模式变化较大(丘地减去空心率从−1到+1.5 g N m−2 yr−1)，高丘的氮素积累速率普遍较大，与碳(C)的积累速率相关。在1990-1996年间测得的50年氮素累积速率与大气湿沉降之间存在着适度但显著的正相关，累积速率大约是湿沉降的4倍。氮素沉积和积累的差异主要归因于有机氮沉积、干沉积和氮素固定。50年的S堆积与1990年至1996年湿大气S沉积之间的相关性较弱，但仍很显著，约75%的S沉积在泥炭中。泥炭岩心在不同地下水位条件下模拟N和S沉积的室内实验表明，平均87%和98%的NH4+和NO3−和58%的S沉积在岩心的植被和非饱和带中，支持了野外研究的结果。
Nitrogen (N) and sulfur (S) play important roles in peatlands, through their influence on plant production and peat decomposition rates and on redox reactions, respectively, and peatlands contain substantial stores of these two elements. Using peat N and S concentrations and dry bulk density and 210Pb dating, we determined the rates of N and S accumulation over the past 150 years in hummock and hollow profiles from 23 ombrotrophic bogs in eastern Canada. Concentrations of N and S averaged 0.80% and 0.18%, respectively, generally increased with depth in the profile and there was a weak but significant correlation between N and S concentrations. Rates of N and S accumulation over the past 50–150 years ranged from 0.5 to 4.8 g N m−2 yr−1 and from 0.1 to 0.9 g S m−2 yr−1. There were significant but weak correlations between C, N and S accumulation rates over 50‐, 100‐ and 150‐year periods. Over the last 50 years, rates of S accumulation showed little differentiation between hummocks and hollows, whereas the pattern for N accumulation was more variable (hummock minus hollow rate ranged from −1 to +1.5 g N m−2 yr−1), with hummocks generally having a larger N accumulation rate, correlated with the rate of carbon (C) accumulation. There was a modest but significant positive correlation between 50‐year rates of N accumulation and wet atmospheric deposition of N measured between 1990 and 1996, with accumulation rates about four times that of wet deposition. The difference between deposition and accumulation of N is attributed to organic N deposition, dry deposition and N2 fixation. A weaker, but still significant, correlation was observed between 50‐year S accumulation and 1990–1996 wet atmospheric S deposition, with about 75% of the deposited S accumulating in the peat. A laboratory experiment with peat cores exposed to varying water table position and simulated N and S deposition, showed that on average 87% and 98% of the deposited NH4+ and NO3−, respectively, and 58% of the deposited S were retained in the vegetation and unsaturated zone of the cores, supporting the results from the field study.