Batty Lesley C, Younger Paul L
Hydrogeochemical Engineering Research and Outreach (HERO) Group, Institute for Research on Environment and Sustainability, University of Newcastle upon Tyne, NE1 7RU, UK.
Chemosphere. 2007 Jan;66(1):158-64. doi: 10.1016/j.chemosphere.2006.05.039. Epub 2006 Jul 3.
The long term effectiveness of compost-based wetland systems treating net-acidic mine waters is reliant upon a continuing supply of decomposed organic matter which provides the basic foodstock for sulphate reducing bacteria. The annual turnover of wetland vegetation within these systems has been suggested to be the primary source for this material once the original substrate has been consumed. This study aimed to determine whether plant litter (of Common Reed, Phragmites australis) decomposition rates and release of metals and nutrients were affected by pH using controlled experiments under laboratory conditions. Loss of plant biomass was found to be unaffected by pH (3.0-6.5) suggesting that plant litter could be an important source of organic molecules for bacterial populations even under acidic conditions. The decomposing plant litter also acted as a focus for the precipitation of Fe oxides and sorption of Zn thereby acting as a short-term sink for these contaminants. This has important implications for geochemical cycling within the wetland system and potential transport out of the system. The essential nutrients (K and Mg) released from plant litter were affected by pH which could be important in nutrient availability for re-use by vegetation and other organisms within the system.
基于堆肥的湿地系统处理酸性矿井水的长期有效性依赖于持续供应分解的有机物质，这种有机物质为硫酸盐还原菌提供了基本的食物来源。一旦原始基质被消耗，这些系统中湿地植被的年度周转被认为是这种物质的主要来源。本研究旨在通过实验室条件下的对照实验，确定植物凋落物（芦苇，Phragmites australis）的分解速率以及金属和养分的释放是否受pH值影响。发现植物生物量的损失不受pH值（3.0 - 6.5）的影响，这表明即使在酸性条件下，植物凋落物也可能是细菌种群有机分子的重要来源。正在分解的植物凋落物还成为铁氧化物沉淀和锌吸附的焦点，从而成为这些污染物的短期汇。这对湿地系统内的地球化学循环以及潜在的系统外迁移具有重要意义。从植物凋落物中释放的必需养分（钾和镁）受pH值影响，这对于系统内植被和其他生物重新利用养分的有效性可能很重要。
