Table 2.

Details of environmental parameters recorded in the different estuaries considered in this study

Site	Filtration technique	Salinity	Surface water temperature (°C)	Dissolved oxygen (mg/L)	Total dissolved nitrate (µM)	Total dissolved ortho‐phosphate (µM)
Columbia estuary	0.22 µm	3.9	19.4	4.95	12.7	0.5
Delaware Bay	0.8 µm followed by 0.22	15.07	23.95	NA	41.95	0.81
Jiulong estuary	0.22 µm	26	28.69	NA	20.27	1.39
Pearl estuary	3 µm followed by 0.22 µm	17.92	28.26	6.68	56.1	0.92
Zhejiang Bay	0.22 µm	29.2	NA	6.88	10.499	0.379
Sundarbans mangrove ecoregion	0.22 µm	10	30	3.4	29	3.4