NON-VOLATILE HYDROCARBON CHEMISTRY STUDIES AROUND A PRODUCTION PLATFORM ON AUSTRALIA'S NORTH WEST SHELF

1998 ◽  
Vol 38 (1) ◽  
pp. 626 ◽  
Author(s):  
K.A. Burns ◽  
S. Codi
Keyword(s):  
High Volume ◽  
Sediment Traps ◽  
Balance Model ◽  
Potential Zone ◽  
Operational Strategies ◽  
Volatile Hydrocarbon ◽  
North West ◽  
The North ◽  
Production Platform ◽  
Hydrocarbon Chemistry

In September 1994 and 1995, scientists from the Australian Institute of Marine Science (AIMS) and the Australian Geological Survey Organisation (AGSO) conducted surveys aboard the Research Vessel Lady Basten to determine the dispersion, fates and effects of Produced Formation Water (PFW) discharged from the Harriet A production platform near the Montebello Islands, on the North West Shelf of Australia. This report describes the non-volatile hydrocarbon chemistry studies.We measured the dispersion of the PFW into dissolved and particulate fractions of seawater using moored high volume water samplers, surface screen samplers and moored and drifting sediment traps. We studied bioaccumulation using transplanted oysters, and we measured dispersion into sediment with benthic grabs. Samples were analysed for total non-volatile hydrocarbons and individual hydrocarbon components using ultraviolet fluorescence spectroscopy (UVF), gas chromatography with flame ionisation detection (GC-FID), and GC with mass selective detection (GC/MS). The hydrocarbon concentrations were used to calculate vertical fluxes and the total concentrations of hydrocarbons in the various ecosystem compartments. A mass balance model was then used to calculate the rates of other important dispersion and degradation processes.We estimate the potential zone of biological impact in the water column extends to a distance of approximately 0.5 nmile (900 m). Concentrations of oil in sediments were too low to indicate potential toxicity. By the collaborative application of oceanographic and geochemical techniques to marine environmental problems, we endeavour to provide effective feedback to the oil industry to gauge the effectiveness of their operational strategies in minimising impact in these pristine regions.

scholarly journals Carbonate sedimentation and effects of eutrophication observed at the Kališta subaquatic springs in Lake Ohrid (Macedonia)

2010 ◽  
Vol 7 (3) ◽  
pp. 4715-4747 ◽  
Author(s):  
M. Matter ◽  
F. S. Anselmetti ◽  
B. Jordanoska ◽  
B. Wagner ◽  
M. Wessels ◽  
...  
Keyword(s):  
Sediment Traps ◽  
Authigenic Carbonate ◽  
Sidescan Sonar ◽  
Carbonate Content ◽  
Carbonate Precipitation ◽  
Lake Ohrid ◽  
Radiocarbon Dates ◽  
North West ◽  
The North ◽  
Spring Area

Abstract. To date, little is known about the role of spring waters with respect to authigenic carbonate precipitation in the shallow lacustrine setting. Lake Ohrid, located in Southeastern Europe, is a large lake fed to over 50% by karstic springs of which half enter subaquatically and influence significantly its ecology and species distribution. In order to evaluate how sedimentological processes are influenced by such shallow-water springs, the Kališta subaquatic spring area in the north west of Lake Ohrid was investigated by a sidescan sonar survey and with sediment traps and three transects of gravity short cores. Results indicate that sedimentation in the spring area is dominated by authigenic carbonate precipitation. High sedimentation rates and evidences for bio-induced precipitation processes were observed in the water column and in the sediments. Two distinct stratigraphic units characterize the shallow subsurface, both composed of carbonate silts with high carbonate contents of up to 96%, but differing in color, carbonate content and diatom content. A chronological correlation of the cores by radiocarbon dates and 137Cs activities places the transition between the two stratigraphic units after ~1955 AD. At that time, coastal sedimentation changed drastically to significantly darker sediments with higher contents of organic matter and more abundant diatoms. This change coincides with the recent human impact of littoral eutrophication.

scholarly journals Carbonate sedimentation and effects of eutrophication observed at the Kališta subaquatic springs in Lake Ohrid (Macedonia)

2010 ◽  
Vol 7 (11) ◽  
pp. 3755-3767 ◽  
Author(s):  
M. Matter ◽  
F. S. Anselmetti ◽  
B. Jordanoska ◽  
B. Wagner ◽  
M. Wessels ◽  
...  
Keyword(s):  
Sediment Traps ◽  
Authigenic Carbonate ◽  
Sidescan Sonar ◽  
Carbonate Content ◽  
Carbonate Precipitation ◽  
Lake Ohrid ◽  
Radiocarbon Dates ◽  
North West ◽  
The North ◽  
Spring Area

Abstract. To date, little is known about the role of spring waters with respect to authigenic carbonate precipitation in a shallow lacustrine setting. Lake Ohrid, located in Southeastern Europe, is a large lake fed to over 50% by karstic springs of which half enter subaquatically and influence significantly its ecology and species distribution. In order to evaluate how sedimentological processes are influenced by such shallow-water springs, the Kališta subaquatic spring area in the north west of Lake Ohrid was investigated by a sidescan sonar survey and with sediment traps and three transects of gravity short cores. Results indicate that sedimentation in the spring area is dominated by authigenic carbonate precipitation. High sedimentation rates and evidences for bio-induced precipitation processes were observed in the water column and in the sediments. Two distinct stratigraphic units characterize the shallow subsurface, both composed of carbonate silts with high carbonate contents of up to 96%, but differing in color, carbonate content and diatom content. A chronological correlation of the cores by radiocarbon dates and 137Cs activities places the transition between the two stratigraphic units after ~1955 AD. At that time, coastal sedimentation changed drastically to significantly darker sediments with higher contents of organic matter and more abundant diatoms. This change coincides with the recent human impact of littoral eutrophication.

TRACKING PRODUCED FORMATION WATER DISCHARGE FROM A PETROLEUM PRODUCTION PLATFORM TO THE NORTH WEST SHELF

1998 ◽  
Vol 38 (1) ◽  
pp. 665 ◽  
Author(s):  
D. Holdway ◽  
D.T. Heggie
Keyword(s):  
Dispersion Model ◽  
Water Discharge ◽  
Spring Tide ◽  
Vertical Profiles ◽  
Formation Water ◽  
Near Surface ◽  
North West ◽  
The North ◽  
Production Platform ◽  
Benzene Toluene

During September 1995, the Australian Geological Survey Organisation and the Australian Institute of Marine Science took part in a joint survey to monitor the dispersion, fates and effects of Produced Formation Water (PFW) discharged from the Harriet A production platform. Continuous Geochemical Tracer(CGT) analysis of benzene, toluene and C1−C6 hydrocarbons was used to map the spatial distribution of the PFW discharge in near surface waters. Hydrographic parameters were also continuously measured and four hydrocarbon vertical profiles were completed at various distances from the platform.PFW collected at the Harriet A production platform contained 3.75 mg/L of C1−C6 hydrocarbons; 1.59 mg/L of benzene and 1.72 mg/L of toluene. Benzene, toluene and total C1−C6 hydrocarbons are sensitive tracers of PFW, with concentrations of benzene and toluene in the PFW plume about 100 fold higher than typical 'detectable background' levels. Maximum concentrations measured within the PFW discharge plume were 140 ng/L for benzene, 250 ng/L for toluene and 1500 ng/L C1−C6 hydrocarbons. Minimum dilutions of about 2,500 for C1−C6 hydrocarbons and less than 10,000+ for benzene and toluene were measured at distances 1 km from the platform. Thus, close to the platform, benzene and toluene are apparently more 'reactive' than C1−C6 hydrocarbons and disperse more rapidly.The PFW discharge was mapped in a NNW and SSE direction on both the ebb and flood tides to a maximum distance of 10 km from the production platform. A net westerly drift of the plume was evident on both the ebb and flood tides toward the Montebello Islands and Varanus Island, rather than toward the east and the mainland. A one dimensional dispersion model found hydrocarbons are dispersed in seawater, with characteristic half-dispersion distances of about 3.5 km on a spring tide. Vertical profiles of PFW hydrocarbons suggest that within 1 km of the platform the PFW plume is primarily a surface feature but beyond 1 km all hydrocarbons are well mixed.

SEM and TEM observations of sperm development in the testis of the freshwater fish Oreochromis mossambicus

1990 ◽  
Vol 48 (3) ◽  
pp. 58-59
Author(s):  
Daryl A. Cornish ◽  
George L. Smit
Keyword(s):  
Morphological Characteristics ◽  
Oreochromis Mossambicus ◽  
Breeding Cycle ◽  
Limited Information ◽  
North West ◽  
The North ◽  
Sem And Tem ◽  
Sperm Development ◽  
Ultrastructural Characteristics ◽  
The University

Oreochromis mossambicus is currently receiving much attention as a candidater species for aquaculture programs within Southern Africa. This has stimulated interest in its breeding cycle as well as the morphological characteristics of the gonads. Limited information is available on SEM and TEM observations of the male gonads. It is known that the testis of O. mossambicus is a paired, intra-abdominal structure of the lobular type, although further details of its characteristics are not known. Current investigations have shown that spermatids reach full maturity some two months after the female becomes gravid. Throughout the year, the testes contain spermatids at various stages of development although spermiogenesis appears to be maximal during November when spawning occurs. This paper describes the morphological and ultrastructural characteristics of the testes and spermatids.Specimens of this fish were collected at Syferkuil Dam, 8 km north- west of the University of the North over a twelve month period, sacrificed and the testes excised.

The North West Passage

2014 ◽  
Author(s):  
Roald Amundsen ◽  
Godfred Hansen
Keyword(s):  
North West ◽  
The North
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