Sediment elevation transects for the Seagrass Recovery Experiment, South Bay, VA 2022

To understand intra-meadow stability, the Seagrass Recovery Experiment was designed to ask 1) is recovery faster at sites with less thermal stress owing to greater exchange with cooler oceanic water at the meadow edge? 2) what is the shape of recovery? and 3) what are the recovery mechanisms? To conduct this experiment, aboveground seagrass biomass was removed from 28.3 m2 plots within the interior and along an edge of a restored seagrass meadow in South Bay, VA. Sites 1-3 correspond to the meadow interior while sites 4-6 correspond to the northern meadow edge. Each site was comprised of a control (i.e., C) where no seagrass was disturbed and a treatment (i.e., T) where seagrass was removed (n = 12 sites total, e.g., 1C, 1T, 2C...). A nor'easter storm moved through the area in early May 2022 producing 59% and 48% of the year's total Gale and Near Gale force winds. After the storm passed, depressions were noticed within the edge treatment sites. To quantify the depression depths a survey of the sediment surface depth was coordinated among all sites in October 2022. Results provide evidence that the edge treatment sites were depressed by 9.4-10.4 cm relative to outside of the treatment plots.

为探究海草床（seagrass meadow）内部的稳定性，本研究设计了海草恢复实验（Seagrass Recovery Experiment），旨在回答三个核心问题：1）在海草床边缘因与较冷海水交换更强而热应激更低的位点，恢复速度是否更快？2）海草恢复的过程形态如何？3）海草恢复的机制是什么？为开展本实验，研究人员于弗吉尼亚州南湾一处修复完成的海草床内部及边缘区域，在28.3平方米的样方中移除了海草的地上生物量，其中位点1至3对应海草床内部区域，位点4至6对应海草床北部边缘区域。每个位点均设置对照组（标记为C，海草未受扰动）与处理组（标记为T，海草被移除），实验共设置12个位点（例如1C、1T、2C等）。2022年5月初，一场东北风暴（nor'easter storm）席卷该区域，其产生的Gale级强风与Near Gale级近强风风速，分别占该年度总对应级别强风风速的59%与48%。风暴过境后，研究人员在边缘区域的处理组样方内发现了沉积物凹陷。为量化该凹陷的深度，研究团队于2022年10月对所有位点的沉积物表面高程开展了协同测量。实验结果表明，相较于处理组样方外侧区域，边缘区域的处理组样方沉积物表面下沉了9.4至10.4厘米。