Peyssonnelia abundance along the south shore of St. John, US Virgin Islands from surveys during 2015

<p>The abundance of the peyssonnelid algal crust was measured using 50 m video transects (recorded with a GoPro Hero 3) at 3, 5, and 7 m depth at five sites, haphazardly selected between Cabritte Horn and White Point on the south shore of St. John. Still images (n = 20 transect-1, each ~ 250 cm2) were randomly extracted and analyzed for percentage cover of peyssonnelids using a grid of 25 squares that were scored for dominance by this alga (i.e., 4% resolution).</p>

本研究采用50米视频样带法（使用GoPro Hero 3摄像机录制），于圣约翰南岸卡布里特角（Cabritte Horn）与怀特角（White Point）间随机选取的5个站点，在3、5、7米水深下测定了皮丝藻结壳藻类（peyssonnelid algal crust）的丰度。从每个样带中随机提取20张静态图像（单张面积约250 cm²），采用含25个方格的网格对皮丝藻的盖度百分比进行分析；该网格以该藻类的优势度作为评分依据，分辨率达4%。