Suppression of dissolved organic carbon by sulfate induced acidification during simulated droughts

被引:81
作者
Clark, JM [1 ]
Chapman, PJ
Heathwaite, AL
Adamson, JK
机构
[1] Univ Leeds, Earth & Biosphere Inst, Sch Geog, Leeds LS2 9JT, W Yorkshire, England
[2] Univ Lancaster, Ctr Sustainable Water Management, Lancaster Environm Ctr, Lancaster LA1 4YQ, England
[3] Lancaster Environm Ctr, Environm Change Network, Ctr Ecol & Hydrol, Lancaster LA1 4YQ, England
基金
英国自然环境研究理事会;
关键词
D O I
10.1021/es051488c
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
The relationship between dissolved organic carbon (DOC) and the acidification of soils and freshwaters by sulfate (SO42-) has been a topic of great debate over the last few decades. Most interest has focused on long-term acidification. Few have considered the influence of episodic drought-induced acidification in peatlands on DOC mobility, even through the increased acidity and ionic strength associated with the oxidation of reduced sulfur to SO42- are known to reduce DOC solubility. Reduced DOC concentrations during droughts have often been attributed to: (i) reduced hydrological export; (ii) physicochemical changes in the peat structure; or(iii) changes in the biological production and/or consumption of DOC. Our experimental drought simulations on peat cores showed that SO42- induced acidification reduced DOC concentrations during droughts, However, the relationships between SO42-/pH/ ionic strength and DOC were only apparent when the reductions in observed DOC were expressed as a fraction of the estimated DOC concentration in the absence of S 204, which were derived from soil depth, temperature, and watertable data. This analysis showed that a pH fall from 4.3 to 3.5, due to a SO42- rise from < 2.5 to 35 mg L-1, caused a 60% reduction in DOC concentrations. In contrast, poor correlations were recorded between SO42-/pH/ionic strength and the observed DOC data. As DOC both influences acidity and is influenced by acidity, the relative change in DOC needed to be considered to disentangle the effect of inputs of mineral acids into a system naturally dominated by variable concentrations of organic acids.
引用
收藏
页码:1776 / 1783
页数:8
相关论文
共 40 条
[1]   Ionic concentrations in a blanket peat bog in northern England and correlations with deposition and climate variables [J].
Adamson, JK ;
Scott, WA ;
Rowland, AP ;
Beard, GR .
EUROPEAN JOURNAL OF SOIL SCIENCE, 2001, 52 (01) :69-79
[2]   Influence of pH and temperature on microbial activity, substrate availability of soil-solution bacteria and leaching of dissolved organic carbon in a mor humus [J].
Andersson, S ;
Nilsson, SI .
SOIL BIOLOGY & BIOCHEMISTRY, 2001, 33 (09) :1181-1191
[3]  
[Anonymous], 1950, InNed. Akad. Wetensch. Proc. Ser. A
[4]  
[Anonymous], 2002, CLIMATE CHANGE SCENA
[5]  
[Anonymous], 1996, UK ENV CHANGE NETWOR
[6]   Experimental response of peatland carbon dynamics to a water table fluctuation [J].
Blodau, C ;
Moore, TR .
AQUATIC SCIENCES, 2003, 65 (01) :47-62
[7]   Influence of drought-induced acidification on the mobility of dissolved organic carbon in peat soils [J].
Clark, JM ;
Chapman, PJ ;
Adamson, JK ;
Lane, SN .
GLOBAL CHANGE BIOLOGY, 2005, 11 (05) :791-809
[8]  
CLARK JM, THESIS U LEEDS LEEDS
[9]   Sulphate mobilization and pore water chemistry in relation to groundwater hydrology and summer drought in two conifer swamps on the Canadian Shield [J].
Devito, KJ ;
Hill, AR .
WATER AIR AND SOIL POLLUTION, 1999, 113 (1-4) :97-114
[10]   Acid induced changes in DOC quality in an experimental whole-lake manipulation [J].
Donahue, WF ;
Schindler, DW ;
Page, SJ ;
Stainton, MP .
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 1998, 32 (19) :2954-2960