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.

The main purpose of the study was to gain a greater understanding of the chemical and biological characteristics of sites in the D'Entrecasteaux Channel and offshore of the Derwent Estuary between North West Bay and Betsey Island. Four transects were completed on the 5th and 6th of April 2022 to achieve this. A SBE 55 ECO Water Sampler Conductivity, Temperature and Depth (CTD) Rosette was used to collect depth, temperature, conductivity, salinity, density, dissolved oxygen, pH, turbidity, fluorescence and pressure data. Water samples collected at three depths using Niskin bottles were used to obtain discrete measurements of oxygen, pH, alkalinity and phosphorous at sea, and discrete measurements of chlorophyll-a, ammonia, NOx, nitrite, nitrate, phosphate and silicate in a laboratory setting. A plankton tow net was used to roughly measure the abundance of plankton at each site and a Secchi disk was used to discern the Secchi depth.