Derwent Estuary water sampling (KSA224 assessment 2025)

The aim of this trip was to investigate the salt wedge of the Derwent estuary, looking at the different properties along and across the estuary. This was achieved by examining; temperature, salinity, chlorophyll-a concentration, nutrients (including nitrate, ammonia, phosphate and silicate), pressure, turbidity, fluorescence, dissolved oxygen and pH. Sampling took place in the morning, in sunny, relatively calm conditions with the low tide on the sampling day at approximately 11:04 am. Two transects were used, with three different locations tested along the estuary and four tested across, at the approximate locations: (-42.94014, 147.38385), (-42.96321, 147.57525), (-42.98388, 147.37083), (-42.9795, 147.336), (-42.9744, 147.3585), (-42.97594, 147.36394) and (-42.97616, 147.38914). Sampling consisted of CTD sensor measurements, a plankton net tow, Secchi disk measurements, and a collection of water samples for analysis.