Derwent Estuary and D'Entrecasteaux Channel water sampling (KSA324 assessment 2022)

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.

Identification info

Date (Publication): 2025-07-07T00:00:00

Resource provider

Institute for Marine and Antarctic Studies (IMAS)

Private Bag 129

Hobart

Tasmania

7001

Australia

Author

Institute for Marine and Antarctic Studies - Montanaro, Kelvin

IMAS - Hobart

Private Bag 129

Hobart

Tasmania

7001

Australia

Point of contact

Institute for Marine and Antarctic Studies - van der Merwe, Piere

IMAS - Hobart

Private Bag 129

Hobart

TAS

7001

Australia

ORCID ID >

Credit: IMAS KSA 324 Oceanographic Methods

Credit: KSA324/724 Oceanographic Methods class 2022 (IMAS)

Status: Completed

Author

Institute for Marine and Antarctic Studies - Montanaro, Kelvin

Private Bag 129

Hobart

Tasmania

7001

Australia

ORCID ID >

Point of contact

Institute for Marine and Antarctic Studies - van der Merwe, Piere

Private Bag 129

Hobart

TAS

7001

Australia

ORCID ID >

Topic category

Oceans

Extent

Temporal extent

Time period: 2022-04-05 2022-04-06

Vertical element

Minimum value: 0.5

Maximum value: 28.5

Identifier: EPSG::5715

Name: MSL depth

Maintenance and update frequency: Not planned

Keywords (Theme)

Global Change Master Directory Earth Science Keywords, Version 8.5

Australian and New Zealand Standard Research Classification (ANZSRC): Fields of Research

Resource constraints

Use limitation: Data, products and services from IMAS are provided "as is" without any warranty as to fitness for a particular purpose.

Use limitation: The data described in this record are the intellectual property of the University of Tasmania through the Institute for Marine and Antarctic Studies.

Resource constraints

Linkage: https://licensebuttons.net/l/by/4.0/88x31.png
License Graphic

Title: Creative Commons Attribution 4.0 International License

Alternate title: CC-BY

Edition: 4.0

Website: https://creativecommons.org/licenses/by/4.0/
License Text

Other constraints: The citation in a list of references is: "Citation author name/s (year metadata published), metadata title. Citation author organisation/s. File identifier and Data accessed at (add http link)."

Language: English

Character encoding: UTF8

Content Information

Content type: Physical measurement

Identifier

Code: Lat

Name: Latitude

Name: Decimal degrees

Identifier

Code: Long

Name: Longitude

Name: Decimal degrees

Identifier

Code: Date

Name: dd/mm/yyyy

Identifier

Code: Depth

Name: Metres (m)

Identifier

Code: Temp

Name: Temperature

Name: Degrees Celsius (°C)

Identifier

Code: Conduct

Name: Conductivity

Name: Siemens per metre (S/m)

Identifier

Code: Sal

Name: Salinity

Name: Practical Salinity Unit (PSU)

Identifier

Code: Dens

Name: Density

Name: Kilograms per metre cubed (kg/m^3)

Identifier

Code: Oxy

Name: Dissolved Oxygen

Name: Millilitres per litre (mL/L)

Identifier

Code: pH

Name: pH

Identifier

Code: Turbidity

Name: Nephelometric Turbidity unit (NTU)

Identifier

Code: Fluor

Name: Fluorescence

Name: Milligrams per metre cubed (mg/m^3)

Identifier

Code: Desc_rate

Name: Descent rate

Name: Metres per second (m/s)

Identifier

Code: Press

Name: Pressure

Name: Decibars (dbar)

Identifier

Code: Oxy_disc

Name: Discrete Dissolved Oxygen

Name: Millilitres per litre (mL/L)

Identifier

Code: pH_disc

Name: Discrete pH

Name: pH

Identifier

Code: Alk_disc

Name: Discrete Alkalinity

Name: Parts per million (ppm)

Identifier

Code: Phosph_disc

Name: Discrete Phosphorus

Name: Parts per million (ppm)

Identifier

Code: Chloro

Name: Chlorophyll-a Concentration

Name: Milligrams per metre cubed (mg/m^3)

Identifier

Code: Ammonia

Name: Micromolar (μM)

Identifier

Code: NOx

Name: Micromolar (μM)

Identifier

Code: Nitrite

Name: Micromolar (μM)

Identifier

Code: Phosph

Name: Phosphate

Name: Micromolar (μM)

Identifier

Code: Silicate

Name: Micromolar (μM)

Identifier

Code: Secchi

Name: Secchi Depth

Name: Metres (m)

Identifier

Code: Plankton

Name: Plankton abundance

Name: Millilitres per metre (ml/m)

Identifier

Code: Station_name

Name: Station name

Name: Transect and site number

Identifier

Code: Time

Name: Seconds

Identifier

Code: Bot_depth

Name: Bottle Depth

Name: Metres (m)

Identifier

Code: Oxy_disc_flag

Name: Discrete dissolved oxygen data flag

Name: 1 = acceptable, 2 = questionable, 3 = unacceptable

Identifier

Code: Alk_disc_flag

Name: Discrete alkalinity data flag

Name: 1 = acceptable, 2 = questionable, 3 = unacceptable

Identifier

Code: Chloro_flag

Name: Chlorophyll-a concentration data flag

Name: 1 = acceptable, 2 = questionable, 3 = unacceptable

Identifier

Code: Nitrate

Name: Micromolar (μM)

Identifier

Code: Plankton_flag

Name: Plankton abundance data flag

Name: 1 = acceptable, 2 = questionable, 3 = unacceptable

Distribution Information

Distribution format

CSV (Comma delimited)

OnLine resource: DATA DOWNLOAD - <Water Sampling Data> (40KB CSV)

Resource lineage

Statement: SITE INFORMATION AND LOG SHEETS Research sites were chosen along four transects. Transect A (TA) was conducted between North West Bay and South Arm. Transect B (TB) was conducted between Betsey Island and Bruny Island. Transect C (TC) and D (TD) were conducted in the D’Entrecasteaux Channel. TA and TC had four sites each, whereas TB and TD had three sites each. Event log sheets, conductivity, temperature and depth (CTD) log sheets and Secchi disk and plankton log sheets were used to record data, station information, notes and who was responsible for specific tasks. TA and TC were completed on April 5th 2022 and TB and TD were completed on April 6th 2022. CTD DATA The SBE 55 ECO Water Sampler CTD rosette was used at each site to obtain depth, temperature, conductivity, salinity, density, dissolved oxygen, pH, turbidity, fluorescence and pressure data. The SBE 55 ECO Water Sampler’s pH, conductivity, temperature, pressure, dissolved oxygen and combined fluorescence and turbidity sensors measured their respective properties, from which salinity, density, and depth were additionally derived. The Seaterm AF V2 Seabird software was used to configure the SBE 55 ECO Water Sampler before deployment and obtain data. A calibration file and the SBEDataProcessing-win32 Seabird software was used to process the raw data to convert it into data with meaningful units. The MATLAB file ‘average_data_KSA324_V2_22’ was then used to further process the data by selecting the upcast data and then averaging the water properties for each metre of water depth. This method was repeated for each site that was sampled. DISCRETE MEASUREMENTS The CTD possessed three 5L Niskin bottles that collected three discrete water samples from the water column as it was ascending. The water samples were first used to measure dissolved oxygen. 125mL BOD bottles were rinsed three times and then filled with water samples, ensuring that no bubbles were incorporated into the samples, and then each measured with an Intellical LDO101 LDO probe twice. The pH of the water samples was then measured. 100mL sample containers were rinsed three times and then filled with the water samples. The pH of each of these samples was measured three times using an Intellical PHC201 series pH probe, which was rinsed with deionised water in between samples. Chlorophyll-a concentration was measured using the following procedure. 500mL amber bottles were rinsed three times and then filled with the water samples. They were then filtered onto glass fibre filters, which were subsequently placed in glass vials, wrapped in foil and labelled. Back in the laboratory, these filters were submerged in 10 mL of 90% acetone, and extracted for 12 hours at 4°C. They were then measured on a Turner 10-AU Fluorometer, acidified with hydrochloric acid, and then measured in the fluorometer again. The difference between these two measurements gave the chlorophyll-a concentration. Alkalinity and phosphorus were measured at sea using HANNA Instruments phosphate and alkalinity Marine checkers. To measure nutrients, 30mL tubes were rinsed three times and then filled with water samples. These were then sent to the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Hobart Hydrochemistry Laboratory and analysed using an AA3 Segmented Flow Analyser. These methods were repeated for the water samples collected at each site. Data flags were subsequently used to identify any data which may be invalid or concerning if necessary. SECCHI DISK AND PLANKTON TOW NET The Secchi depth at each site was determined using a Secchi disk. The disk was lowered slowly until it was no longer visible. This depth was recorded. The disk was then raised again until it was visible again. This depth was also recorded. These two depths were then averaged to get the Secchi depth. This method was sometimes repeated to measure precision. Plankton abundance was determined using a plankton tow net. Before it was deployed, the start reading of an attached flowmeter was recorded. The net was then deployed for roughly 5 minutes. Once retrieved, the end reading of the flowmeter was recorded, and the net was rinsed down. The initial volume of the plankton net contents was recorded, passed through a sieve, and then recorded again. The difference between these measurements gave the displaced volume of plankton collected by the plankton net. This was normalised by dividing the displaced volume with the distance the plankton net was towed. These methods were repeated at each site that was sampled. Data flags were subsequently used to identify any data which may be invalid or concerning if necessary.

Hierarchy level: Dataset

Hierarchy level: Dataset

Metadata

Metadata identifier: urn:uuid/8845563c-bc69-4bf6-bebb-231d1f21d60a

Language: English

Character encoding: UTF8

Distributor

IMAS Data Manager - Data Officer

Institute for Marine and Antarctic Studies

Private Bag 129

Hobart

Tasmania

7001

Australia

Institute for Marine and Antarctic Studies (IMAS) website >

Type of resource

Resource scope: Dataset

Name: IMAS Dataset level record

Metadata linkage: https://metadata.imas.utas.edu.au/geonetwork/srv/eng/catalog.search#/metadata/8845563c-bc69-4bf6-bebb-231d1f21d60a
Point of truth URL of this metadata record

Date info (Creation): 2022-04-25T00:00:00

Date info (Revision): 2025-07-07T16:26:13

Metadata standard

Title: ISO 19115-3:2018

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