ABSTRACT

Wetlands physical and biological processes are fundamental to the distribution and structuring of organic matter in sediments. This study investigated spatial and temporal changes in organic matter sources in sediments within the Nylsvley Wetland, South Africa across two seasons, five sites and three wetland zones and identified pertinent contributors to sediment organic matter. Results showed distributions were uneven throughout the wetlands, with the seasonal zone having slightly high sediment organic matter in the cool-dry season and the permanent zone had high sediment organic matter in the hot-wet season, whereas the temporary zone had low SOM concentrations. Significant differences in nutrient concentrations were observed across wetland zones and seasons for Phosphorous, Potassium, Calcium and Magnesium, with the seasonal zone tending to be the most nutrient-rich in the cool-dry season, and with permanent zone nutrient levels rising substantially in the hot-wet season. Sediment δ¹³C differed significantly among wetland zones, whereas δ¹⁵N was statistically similar. Autochthonous plants were the main sources of organic matter in sediments overall across sites and zones. This study’s findings help to better understand the distribution of organic matter in wetland ecosystems and the role wetland zones play in the seasonal provisioning of allochthonous inputs.

摘要

湿地的物理和生物过程是沉积物中有机物分布和结构的基础。本研究调查了南非 Nylsvley 湿地两个季节、五个地点和三个湿地区沉积物中有机质来源的时空变化，并确定了沉积物有机质的相关贡献者。结果表明，整个湿地分布不均匀，季节性带在冷旱季沉积物有机质略高，永久带在湿热季节沉积物有机质高，而临时带有机质浓度较低。不同湿地区域和季节的磷、钾、钙和镁的养分浓度存在显着差异，季节性区域往往在冷旱季营养最丰富，而永久区域的营养水平在湿热季节大幅上升。沉积物δ^{湿地区域之间的13} C 差异显着，而 δ ¹⁵ N 在统计上相似。本土植物是整个地点和区域沉积物中有机物的主要来源。本研究的结果有助于更好地了解湿地生态系统中有机物的分布以及湿地区域在季节性提供外来输入物中所起的作用。