West Falmouth Harbor Eelgrass Bed Extent, 2010-2019, generalized

West Falmouth Harbor (West Falmouth, MA, USA) has been experiencing a dramatic increase in nitrogen loading from an upgradient municipal wastewater treatment facility since the early 2000’s. As part of a long-term study into the effects of this nitrogen enrichment, we have been assessing changes in the extent and health of the eelgrass (Zostera marina) community within the harbor. We conducted side scan sonar surveys and analyzed them using SonarWiz and ArcGIS to delineate the extent of continuous seagrass bed within the harbor. The goal of this dataset is to assess changes in eelgrass habitat extent; small bare patches within the larger seagrass bed due to anchor scars and mooring scouring were not digitized. Groundtruthing of the edges was done with a combination of diver surveys, underwater video, and surface surveys at low tide. Surveys were run in every year from 2010 through 2022 and we plan to continue them into future years. Data analysis is ongoing and shapefiles will be added as they are run through quality assessment. Details for the 2010 data collection and analysis are detailed in Hayn 2012: Exchange of nitrogen and phosphorus between a shallow estuary and coastal waters, Appendix 3, permanently archived at https://hdl.handle.net/1813/31380.

美国马萨诸塞州西法尔茅斯的西法尔茅斯港，自21世纪初以来，因上游市政污水处理厂的排放，氮负荷持续急剧攀升。作为该氮富集效应长期研究的组成部分，我们正对港内鳗草（Zostera marina）群落的分布范围与健康状态变化开展评估。我们采用侧扫声呐（side scan sonar）进行野外勘测，并借助SonarWiz与ArcGIS软件分析采集数据，以划定港内连片海草床的分布范围。本数据集旨在评估鳗草生境的范围变化；因锚痕与系泊冲刷形成的大型海草床内小型裸露斑块，未纳入数字化勾绘范畴。海草床边界的实地验证工作，结合了潜水员勘测、水下视频记录与低潮时段的水面勘测三种方式。2010年至2022年期间每年均开展此项勘测，我们计划未来继续推进相关工作。目前数据分析仍在进行中，经质量评估后的形状文件（shapefiles）将陆续补充至本数据集。2010年的数据采集与分析细节，详见Hayn于2012年发表的《浅河口与近岸水体间氮磷交换》一文附录3，该文献永久存档于https://hdl.handle.net/1813/31380。