Seagrass leaf nutrient and trace metal content

In addition, seagrass leaves were used as bioindicators for nutrient pollution (Govers et al., 2014a) and trace metal pollution (Govers et al., 2014b) because they integrate environmental conditions over time and therefore record ecologically relevant levels (Fabricius et al., 2012). Seagrass leaves were only collected from the two inland bay sites and only in the wet season (November 2020). Ten shoots (1 m distance between shoots) of Thalassia testudinum and Halophila stipulacea with roots were collected in Spaanse Water Bay, whereas only 10 shoots of Halophila stipulacea were collected in Santa Martha Bay due to the absence of Thalassia testudinum. The seagrass shoots were split into roots, rhizomes, and leaves, after which only the leaves were used. The dried seagrass leaves were then analysed for trace metal concentrations (As, Cd, Co, Cr, Cu, Fe, Ni, P, Pb, Se, Zn) and ratios and percentages of carbon (C), nitrogen (N) and phosphate (P).