Nitrate removal across ecogeomorphic zones in Wax Lake Delta, Louisiana (USA) Supplemental Data

To understand the spatial distribution of nitrate removal in a river-dominated delta, we deployed 23 benthic chambers across ecogeomorphic zones with varying elevation, vegetation and sediment properties in Wax Lake Delta (Louisiana, USA) in June 2018. Regression analyses indicate that NDVI, a remotely sensed vegetation index, is a useful predictor of summertime nitrate removal. On average, potential removal rates were approximately three times greater on a vegetated submerged levee (13 mm hr-1), where NDVI was greatest, compared to other locations (4.6 mm hr-1). To protect coastal waters against high nitrate loads, management policies should aim to reduce upstream nutrient loads.为探明以河流作用为主的三角洲中硝酸盐去除作用的空间分布特征，本研究于2018年6月在美国路易斯安那州瓦克斯莱三角洲（Wax Lake Delta）内，沿海拔、植被与沉积物属性各异的生态地貌带布设了23个底栖腔室。回归分析结果显示，归一化差分植被指数（Normalized Difference Vegetation Index，NDVI）作为一种遥感获取的植被指数，可作为夏季硝酸盐去除速率的有效预测因子。平均而言，植被覆盖的淹没堤岸的潜在硝酸盐去除速率约为13 mm·hr⁻¹，该区域的NDVI值最高，其去除速率约为其他区域（4.6 mm·hr⁻¹）的3倍。为保护近海水体免受高硝酸盐负荷的影响，相关管理政策应致力于削减上游营养盐输入负荷。