Turbidity of a Salt Marsh within the Altamaha River estuary, GA, USA, 2015-2017

We measured turbidity along a transect from channel to marsh interior for 1 year, beginning in June 2016 at a salt mash in the Altamaha River estuary. We measured turbidity (NTU) with three optical back scatter sensors to in a shore normal transect, with one in the channel (YSI 6600), and two on the marsh surface. The “marsh edge sensor” was 2.4m from the channel edge (Seapoint, RBR Solo) and the “marsh interior sensor” was 18m from the edge (Seapoint, RBR Duo; Figure 1c). The sensors measured every 15 minutes and were equipped with automatic wipers to reduce biofouling. Following retrieval, the turbidity time series data was filtered to remove any erroneous points and times when the sensors were fouled or exposed (Ganju et al. 2005). Turbidity was then calibrated to suspended sediment concentration with local sediment resulting in the calibration equation SSC (mg/L) =1.33*Sensor Turbidity (NTU) (R2=0.9345, n=26, p<<0.001).