The nutrient concentrations and
their variation trends in the water column at each sampling site
during the study period are presented in Fig. 2(A–C). There are two main trends in the spatial patterns of DIN and DIP concentrations in seawater. First, a gradient of Transect 1 > Transect 2 > Transect 3 (with the exception of the DIP concentrations in the water column, p > 0.05, Fig. 2C) was observed. Second, high intertidal sites exhibited higher seawater DIN and DIP concentrations compared with their respective low intertidal sites, i.e., 1H > 1L, 2H > 2L, and 3H > 3L.