The importance of the relationship between scale and process in understanding long-term DOC dynamics
The importance of the relationship between scale and process in understanding long-term DOC dynamics
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DOI：
10.1016/j.scitotenv.2010.02.046
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发表时间：
2010-06-01
影响因子：
9.8
通讯作者：
Chapman, P. J.
中科院分区：
文献类型：
--
作者：
Clark, J. M.;Bottrell, S. H.;Chapman, P. J.
过去二十年来，欧洲和北美受酸影响地区的许多（但不是全部）地表水中溶解有机碳的浓度有所增加。在过去的八年里，人们提出了一些假设来解释这些增长。但尚未得到普遍接受。这一领域的研究似乎已经陷入僵局，赞成将大气沉降下降、气候变化或土地管理作为长期 DOC 趋势的关键驱动因素。虽然很明显，其中许多因素影响土壤和溪流水中的 DOC 动态，但它们的影响在不同的时间和空间尺度上有所不同。我们认为，酸沉降负荷的区域差异可能解释了研究之间的明显差异。在污染物硫和/或海盐沉积经历了强烈下降趋势的地区，DOC 显示出强烈的单调增加。在其他地方，气候因素对季节性有很大影响。此外，在接受类似酸负荷的地区，不同的流域特征可能会影响特定地点对酸度变化的敏感性，从而影响硫沉降变化引起的 DOC 释放量。我们认为，这些时间和空间调查尺度的混乱不必要地导致了对 DOC 趋势主要区域驱动因素的分歧，并且大多数这些研究背后的数据比经常被传达 (C) 2010 Elsevier BV 版权所有
Concentrations of dissolved organic carbon have increased in many, but not all, surface waters across acid impacted areas of Europe and North America over the last two decades. Over the last eight years several hypotheses have been put forward to explain these increases. but none are yet accepted universally. Research in this area appears to have reached a stalemate between those favouring declining atmospheric deposition, climate change or land management as the key driver of long-term DOC trends While it is clear that many of these factors influence DOC dynamics in soil and stream waters, their effect varies over different temporal and spatial scales We argue that regional differences in acid deposition loading may account for the apparent discrepancies between studies DOC has shown strong monotonic increases in areas which have experienced strong downward trends in pollutant sulphur and/or seasalt deposition. Elsewhere climatic factors, that strongly influence seasonality. have also dominated inter-annual variability, and here long-term monotonic DOC trends are often difficult to detect Furthermore, in areas receiving similar acid loadings, different catchment characteristics could have affected the site specific sensitivity to changes in acidity and therefore the magnitude of DOC release in response to changes in sulphur deposition We suggest that confusion over these temporal and spatial scales of investigation has contributed unnecessarily to the disagreement over the main regional driver(s) of DOC trends, and that the data behind the majority of these studies is more compatible than is often conveyed (C) 2010 Elsevier BV All rights reserved