Brief descriptionA 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. This data includes sampling from Pitt Water / Orielton Lagoon, North West Bay, Port Cygnet, Little Swanport, Moulting Lagoon / Great Swanport.
LineageMaintenance and Update Frequency: notPlanned
The indicators examined for this study were:
· Salinity (ppt)
· Water temperature (oC)
· Dissolved Oxygen (DO) (% Saturation)
· Turbidity (NTU)
· Dissolved nutrients – ammonia (NH4 mg/L), nitrate and nitrite (NOx mg/L), and reactive phosphorus (P mg/L), silica, molybdate reactive (mg/L)
· Chlorophyll a
· Animal/plant species abundance - Benthic macroinvertebrates
The methodology for monitoring each indicator has been described in a report (Crawford 2006, available at http://eprints.utas.edu.au/view/authors/Crawford,_C.html) that provides information from a user’s perspective on monitoring each indicator in Tasmania. The indicators outlined above were examined between April 2007 and April 2008 at monthly intervals.
Temperature, salinity and dissolved oxygen were measured monthly at every site (see Fig 2-6) at 1 m intervals from the surface (0 m) to the bottom of the water column, allowing the construction of vertical profiles. The exact depth of each profile was recorded where the bottom did not fall exactly on a 1 m interval.
Turbidity (NTU) and pH of surface waters were tested at every site. Three replicate samples at every site each month were taken for turbidity measurements and then averaged for graphing purposes.
Dissolved nutrients (ammonia, nitrate plus nitrite (NOx) and soluble reactive phosphorous) and silica were sampled monthly from surface waters at key sites within each estuary. Bottles, syringes and filters were supplied by Analytical Services Tasmania (AST). Samples were kept on ice until returning to the Marine Research Laboratories (MRL) where the silica samples were refrigerated and the dissolved nutrient samples were frozen until they were transferred to AST for analysis within a week of collection. Ammonia, nitrate plus nitrite, dissolved reactive phosphorous and silica were quantified by AST at their NATA accredited laboratory using the APHA Method 4500.
Chlorophyll a - One litre of water was taken from just below the surface at key sites within each estuary for chlorophyll a analysis at the Marine Research Laboratories (MRL), TAFI. Samples were transported to the MRL on ice where the sample was filtered through Whatman GF/C glass microfibre filters, recording the total volume of water filtered. The filters were folded, wrapped carefully in aluminium foil and frozen until analysis could be completed.
Frozen filters were cut into small pieces and added to 10 mL of 90% acetone solution. The filter papers were then macerated in solution for approximately 10 seconds each using a cell disruptor. Tubes were then covered in aluminium foil to block out light and placed in a refrigerator for 12 hours. Tubes were then centrifuged for 15 minutes at 4 500 rpm. Extract was transferred into a glass 1 cm cuvet cell and placed into a Cintra 10 e spectrophotometer.
Absorbance readings were taken at 630 nm, 647 nm, 664 nm and 750 nm with three replicate readings for every sample. These replicates were averaged to give the sample reading and the % standard deviation using the Cintra software package. Chlorophyll a levels were then determined using the Golterman and Clymo equation – see http://dipin.kent.edu/chlorophyll.htm.
Benthic macroinvertebrates - Sediment samples for assessment of invertebrate fauna are collected in shallow water using a hand-held 150 mm diameter PVC pipe corer (sediment depth 100 mm; sample area 0.0177 m2). In deeper water sediment samples are collected either by a diver using the PVC pipe corer or from a boat using a Van Veen Grab (sampling area 0.05 – 0.1 m2).
Five replicate cores were taken from each of the key sites within each estuary during Spring 2007. Two methods were utilised for sampling benthic macroinvertebrates. At shallow sites, five sediment cores were collected from 0.5 m depth using a benthic corer (150 mm diameter, 100 mm deep), whereas at the deeper sites, five benthic grab samples were collected using a Van Veen grab. Sediment samples were washed through a 1 mm mesh sieve and the material retained was collected and stored in 10% formalin/seawater solution for a minimum of 48 hours to ensure complete fixation. It was then stored in 70% alcohol. Invertebrates were sorted and identified to the lowest possible taxonomic level and each taxa counted by staff at the MRL, TAFI. Results of the benthic macroinvertebrate survey completed during Spring 2007 will be released in a supplementary report in late 2008.
Natural Resource Management (NRM) South
Natural Heritage Trust
This projects' data was obtained as part of the trial implementation of the Coastal and Estuarine Resource Condition Assessment (CERCA) project.
Created: 26 03 2015
Data time period: 04 2007 to 30 04 2008
147.6,-42.8 147.6,-42.4 147.49,-42.4 147.49,-42.8 147.6,-42.8
148.25,-42 148.25,-42.1 148.15,-42.1 148.15,-42 148.25,-42
147.35,-43 147.35,-43.1 147.25,-43.1 147.25,-43 147.35,-43
147.1,-43.1 147.1,-43.2 147,-43.2 147,-43.1 147.1,-43.1
148.02,-42.3 148.02,-42.4 147.92,-42.4 147.92,-42.3 148.02,-42.3
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(REPORT - Final project report [direct download])
- global : c1a2a0b4-e33d-4748-a503-5c6016fc0998