Partani Sadegh, Danandeh Mehr Ali, Jafari Ali
Department of Civil Engineering, Faculty of Engineering, University of Bojnord, Bojnord, Iran.
Civil Engineering Department, Antalya Bilim University, Antalya, Turkey; MEU Research Unit, Middle East University, Amman, Jordan.
Sci Total Environ. 2024 May 10;924:171518. doi: 10.1016/j.scitotenv.2024.171518. Epub 2024 Mar 8.
This study investigates the impact of pneumatophores (the aerial roots of Avicenna marina) on water flow rate, retention time, contact time, and consequently on nutrient absorption through the sediment in sub-tropical salt marshes. The goal is to realize how the density of mangroves in salt marshes influences the kinematic factors of streamflow at estuaries. To this end, a field experiment was carried out to assess nutrient and organic compound levels in the sediment and water samples, spanning six sampling stations along the Chabahar River discharging to the Chabahar Bay, Iran. Then, we delved into the influence of altering environmental parameters, such as density and geometry, on the kinematic features of the flow through statistical analysis and hydraulic modeling. The results showed that the aerial roots reduce the flow rate and increase both retention and contact times. The longest retention time was observed at station #5 due to increased vegetation density and decreased instream velocity. In addition, measurements of total organic matter, total organic carbon, and total nitrogen indicated that an extended contact time resulted in increased absorption flux to the stream by sediments. As a result, pneumatophores can serve as an effective sink for organic matter in ecotones in salt marshes.
本研究调查了呼吸根（白骨壤的气生根）对亚热带盐沼中水流速、滞留时间、接触时间的影响，进而研究其对通过沉积物的养分吸收的影响。目的是了解盐沼中红树林的密度如何影响河口处水流的运动学因素。为此，进行了一项野外实验，以评估沉积物和水样中的养分及有机化合物水平，该实验在伊朗恰巴哈尔河注入恰巴哈尔湾沿线的六个采样站进行。然后，我们通过统计分析和水力建模，深入研究了改变环境参数（如密度和几何形状）对水流运动学特征的影响。结果表明，气生根降低了流速，增加了滞留时间和接触时间。由于植被密度增加和河道内流速降低，在5号站观测到最长的滞留时间。此外，对总有机质、总有机碳和总氮的测量表明，延长的接触时间导致沉积物对河流的吸收通量增加。因此，呼吸根可作为盐沼生态交错带中有机物的有效汇。
