Brief description
The mass balance and activity ratios of naturally occuring radium (Ra) isotopes (223Ra, 224Ra, 226Ra, 228Ra) were investigated in Cockburn Sound, W.A. to further understand submarine groundwater discharge (SGD) into this coastal water. Water samples from 11 marine stations and 20 groundwater sites (encompassing three aquifer layers) were analysed for Ra at four times, at the end of winter (September 2003), early summer (December 2003), late summer (March 2004) and mid-winter (July 2004).Lineage
Maintenance and Update Frequency: notPlanned
Statement: - Field sampling -
A seasonal marine and groundwater sampling program was conducted for Ra and nutrient analysis. Sampling dates were 22-24 Sept 2003, 30 Nov-2 Dec 2003, 8-10 Mar 2004, and 15-20 Jul 2004. Sampling locations are shown in thumbnail and consisted of 10 marine stations (C1-C10) and 16 groundwater stations that covered a variety of groundwater sources.
Marine samples for Ra analysis were pumped from 2 m below the surface and 50 L was collected in plastic drums for single Ra analysis.
Groundwater samples from the sand (SBS) and limestone (TL) aquifers were collected using a hand bailer and a peristaltic hammerhead groundwater pump and deeper Leederville groundwater using a Grundfos pumping station. The well volume was discarded at least twice and stability of pH and DO was established prior to sample collection. One 25 L sample was collected from each well for Ra analysis, and duplicate nutrient samples were collected as previously described.
Beach porewater (B) samples were collected from holes dug above high tide mark, to characterise the Ra signature of water directly connected to the discharge zone. All sample containers had been pre-washed in Decon 90, acid soaked in 10% HCl for at least 72 hours, thrice rinsed in milliQ deionised water and air dried. Salinity, temperature, pH and DO were measured at all marine and groundwater sampling stations using calibrated hand held TPS WP-81 pH-Cond-Salinity meter with a conductivity probe (part number 122201) and TPS Aqua-D DO meter with a TPS ED1 sensor.
Sediment samples were collected to characterise the sediment of Cockburn Sound and to estimate the Ra benthic flux. On 23 Jan 2006 6 sediment cores were collected from location C6 (see thumbnail) and were combined to form a composite sample. These samples were used to characterise the sediment of the deepest water of Cockburn Sound; the sediment appeared to be a mix of fine mud and coarser sands. Coarse sandy sediments were collected from the shallow flat benthos at locations B1, B2 and B4. All sediments samples were collected from the shallow in Perspex cores (manually by SCUBA from 19 m depth at C6). Cores were kept upright and the overlying water column of each core was siphoned off. The top 2 cm of sediment was sliced off from each sub-sample, and the sub-sample sections were combined.
For laboratory analysis see section 3.3.3 of the thesis.
Notes
CreditStrategic Research Fund for the Marine Environment (SRFME)
Created: 17 08 2007
Data time period: 2003-09-22 to 2006-01-26
text: westlimit=115.5; southlimit=-32.32; eastlimit=115.9; northlimit=-32.03
Subjects
Aquifers |
Conductivity |
Discharge/flow |
EARTH SCIENCE |
GEOCHEMICAL PROPERTIES |
GEOCHEMISTRY |
GROUND WATER |
Groundwater Chemistry |
Isotopes |
OCEAN CHEMISTRY |
OCEANS |
Oxygen |
Oceans | Marine Sediments | Sediment Characteristics |
Ph |
SOLID EARTH |
Stable Isotopes |
SURFACE WATER |
TERRESTRIAL HYDROSPHERE |
WATER QUALITY/WATER CHEMISTRY |
Water Temperature |
oceans |
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Other Information
(PhD Thesis)
Identifiers
- global : cff4c690-4c8c-11dc-b3c3-00188b4c0af8
