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.

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.

This record describes the conductivity-temperature-depth (CTD) data and underway water sample data collected during the CSIRO Investigator transit voyage INVTO1_2024, between 9 March and 20 March 2024. The objective of the voyage was for a safe transit from Fremantle, Western Australia, to Hobart, Tasmania. This record was part of a piggyback project whereby undergraduate students attained at-sea training through the Institute of Marine and Antarctic Studies and the University of Tasmania. The project aim was for students to gain experience with oceanographic data collection, processing and analysis. The CTD data includes 7 CTD profiles that measured conductivity, temperature, pressure, dissolved oxygen, salinity, fluorescence, turbidity and photosynthetically active radiation (PAR). Each of these parameters were collected during each CTD profile. The CTD data also includes calculated measurements of ammonium, nitrate, nitrite, phosphate, silicate, as well as chlorophyll-a, from select rosette bottles. The underway water sample data includes 41 duplicate samples of calculated measurements of chlorophyll-a and associated calculated measurements of ammonium, nitrate, nitrite, phosphate and silicate nutrient concentrations. In both data files, ODV quality flags have been used to indicate data quality.

A 12-month program was developed and implemented in order to obtain baseline information on water quality (salinity, water temperature, dissolved oxygen, turbidity, pH, dissolved nutrients, silica), ecological condition as shown by Chlorophyll a, benthic macroinvertebrates, pathogens, and habitat extent determined from habitat mapping. Five key estuaries and coastal waters were assessed in the Southern NRM Region of Tasmania. The data represented by this record was collected in North West Bay.

This study considered a range of water-column and sediment (benthos) based variables commonly used to monitor estuaries,utilising estuaries on the North-West Coast of Tasmania (Duck, Montagu, Detention, and Black River). These included: salinity, dissolved oxygen, turbidity, nutrient and chlorophyll a levels for the water-column; and sediment redox, organic carbon content, chlorophyll a and macroinvertebrate community structure amongst the benthos. In addition to comparing reference with impacted estuaries, comparisons were also made across seasons, commensurate with seasonal changes in freshwater river input, and between regions within estuaries (upper and lower reaches) - previously identified in Hirst et al. (2005). This design enabled us to examine whether the detection of impacts (i.e. differences between reference and impacted systems) was contingent on the time and location of sampling or independent of these factors. The data represented by this record was collected in the Black River.

A 12-month program was developed and implemented in order to obtain baseline information on water quality (salinity, water temperature, dissolved oxygen, turbidity, pH, dissolved nutrients, silica), ecological condition as shown by Chlorophyll a, benthic macroinvertebrates, pathogens, and habitat extent determined from habitat mapping. Five key estuaries and coastal waters were assessed in the Southern NRM Region of Tasmania. The data represented by this record was collected in Moulting Lagoon/Great Swanport.

A 12-month program was developed and implemented in order to obtain baseline information on water quality (salinity, water temperature, dissolved oxygen, turbidity, pH, dissolved nutrients, silica), ecological condition as shown by Chlorophyll a, benthic macroinvertebrates, pathogens, and habitat extent determined from habitat mapping. Five key estuaries and coastal waters were assessed in the Southern NRM Region of Tasmania. The data represented by this record was collected in Port Cygnet.

This study considered a range of water-column and sediment (benthos) based variables commonly used to monitor estuaries,utilising estuaries on the North-West Coast of Tasmania (Duck, Montagu, Detention, and Black River). These included: salinity, dissolved oxygen, turbidity, nutrient and chlorophyll a levels for the water-column; and sediment redox, organic carbon content, chlorophyll a and macroinvertebrate community structure amongst the benthos. In addition to comparing reference with impacted estuaries, comparisons were also made across seasons, commensurate with seasonal changes in freshwater river input, and between regions within estuaries (upper and lower reaches) - previously identified in Hirst et al. (2005). This design enabled us to examine whether the detection of impacts (i.e. differences between reference and impacted systems) was contingent on the time and location of sampling or independent of these factors. The data represented by this record was collected in the Detention River.

This study considered a range of water-column and sediment (benthos) based variables commonly used to monitor estuaries,utilising estuaries on the North-West Coast of Tasmania (Duck, Montagu, Detention, and Black River). These included: salinity, dissolved oxygen, turbidity, nutrient and chlorophyll a levels for the water-column; and sediment redox, organic carbon content, chlorophyll a and macroinvertebrate community structure amongst the benthos. In addition to comparing reference with impacted estuaries, comparisons were also made across seasons, commensurate with seasonal changes in freshwater river input, and between regions within estuaries (upper and lower reaches) - previously identified in Hirst et al. (2005). This design enabled us to examine whether the detection of impacts (i.e. differences between reference and impacted systems) was contingent on the time and location of sampling or independent of these factors. The data represented by this record was collected in the Duck Bay.