ORCID Profile
0000-0002-9360-5556
Current Organisations
University of Queensland
,
University of Adelaide
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Publisher: Canadian Science Publishing
Date: 05-1985
DOI: 10.1139/M85-091
Abstract: In estuarine sediments with a high degree of vertical heterogeneity in reduced substrate and terminal electron acceptor concentrations, the method of exposure of the microbiota to labeled substrates can introduce a "disturbance artifact" into measures of metabolic activity. The detection of this artifact is based on a quantitative measurement of the relative rates of incorporation of [ 14 C]acetate into phospholipid fatty acids (PLFA) and endogenous storage lipid, poly-beta-hydroxyalkanoate (PHA). Previous studies have shown that PLFA synthesis measures cellular growth and that PHA synthesis measures carbon accumulation (unbalanced growth). The "disturbance artifact" of exposure to [ 14 C]acetate was demonstrated by comparing injection of a core with the usual or pore-water replacement or slurry techniques. Only injection of labeled substrate allowed detection of a preassay disturbance of the sediment with a garden rake. The raking increased PLFA synthesis with little effect on PHA synthesis. The differences between injection and slurry inoculation techniques on disturbed sediments were not due to differences in concentration or distribution of [ 14 C]acetate in the 10-min incubation. Bioturbation induced by sand dollar feeding in estuarine sediment could be detected in an increased PLFA/PHA ratio which was due to decreased PHA synthesis if the addition of labeled substrate was by the injection technique. Addition of labeled precursors to sediment by slurry or pore-water replacement induces greater disturbance artifacts than injection techniques.
Publisher: Springer Science and Business Media LLC
Date: 12-1991
DOI: 10.1007/BF02540212
Publisher: Wiley
Date: 09-1973
Publisher: Elsevier
Date: 1990
Publisher: The Royal Society
Date: 18-12-1973
Abstract: The fauna of Lake George is dominated by herbivores, in particular the fish Tilapia nilotica and Haplochromis nigripinnis , and the cyclopoid copepod Thermocyclops hyalinus . Digestion, and the assimilation of carbon from algae, by these herbivores were studied in detail. It was found that, contrary to previous observations reported in the literature, both fish and zooplankton were able to digest and assimilate blue-green algae. The diurnal feeding patterns of the herbivores were examined, and methods devised for assessing, in terms of carbon, the daily ingestion of algae. Hence, using biomass data, the total amount grazed by the herbivores was calculated. Estimates of carbon requirements at other trophic levels were made, as was an assessment of the required level of net production by the algae for comparison with figures for standing crop and net algal production measured by other means. Food selection by secondary and tertiary producers is discussed, and in several species age correlated changes in selectivity were examined. Both the major herbivorous species of fish adopt phytoplankton feeding after a period of carnivorous or omnivorous feeding as fry. Thermocyclops hyalinus is herbivorous all its life, but the size of particle taken changes with age. There are more species of carnivorous than herbivorous fish and these exploit a wider variety of food sources the few species studied also show changes in food preference with age.
Publisher: Elsevier BV
Date: 05-1976
Publisher: Springer Science and Business Media LLC
Date: 10-1987
DOI: 10.1007/BF00301375
Publisher: Inter-Research Science Center
Date: 1981
DOI: 10.3354/MEPS005151
Publisher: Springer Science and Business Media LLC
Date: 06-1982
DOI: 10.1007/BF02011456
Publisher: Elsevier BV
Date: 03-1996
Publisher: Elsevier BV
Date: 04-1983
Publisher: Springer Science and Business Media LLC
Date: 1996
DOI: 10.1007/BF00175071
Publisher: Elsevier BV
Date: 1997
Publisher: Inter-Research Science Center
Date: 1991
DOI: 10.3354/MEPS069149
Publisher: EDP Sciences
Date: 07-2022
Publisher: Hindawi Limited
Date: 03-2008
Publisher: CSIRO Publishing
Date: 1994
DOI: 10.1071/MF9940265
Abstract: To describe the influence of hydrology on the phytoplankton communites of the Gulf of Carpentaria, six phytoplankton parameters were measured on five transects: productivity, biomass, community structure, phospholipid-derived fatty acids, ratios of stable carbon isotopes and the relationship between photosynthesis and irradiance. The mean (�s.e.) estimate of depth-integrated phytoplankton productivity was 914�185 mgC m-2 day-' (n=9). In the shallow ( m) coastal waters, the productivity was 1430�400 mgC m-2 day-1 (n = 3). At the offshore stations (=30 m), it was 660 �108 mgC m-2 day-1 (n = 6). At both the shallow and the offshore stations, primary productivity was distributed equally between the phytoplankton size fractions 0.6-2.0�m and 10�m, with little in between. The highest rates of growth occurred within a very narrow light regime: self-shading limited growth in deeper water (at light intensities less than 125 mol s-1 m-2), and growth was photoinhibited in shallow water (at light intensities greater than 150 mol s-1 m-2). The resulting biomass-specific primary productivity (mgC mChla-1 day-1) maximum did not coincide with the depth of either the chlorophyll a maximum or the highest nutrient concentration. The natural carbon isotope ratio for the particulate matter showed that little land-derived carbon was exported beyond a narrow coastal fringe (about 10 to 20 km). The profiles of phospholipid fatty acids also showed that particulate organic matter was dominated by algal-derived compounds, which confirms that the bulk of the organic matter in the offshore Gulf of Carpentaria is of marine origin. Therefore, during the summer in this study, the stratified waters of the central gulf were both biologically and hydrologically independent of the coastal water and not influenced by terrestrial runoff. The phytoplankton production in the central gulf is maintained by nutrient supplies from internal sources, such as those that are remineralized in and resuspended from the sediment.
Publisher: Wiley
Date: 07-1993
DOI: 10.2307/1940076
Publisher: Springer Science and Business Media LLC
Date: 07-1979
DOI: 10.1007/BF00389189
Publisher: CSIRO Publishing
Date: 1982
DOI: 10.1071/MF9820255
Abstract: Organic carbon and nitrogen and bacterial biomass were measured in the sediments and gut contents of H. atra and S. chloronotuson the Great Barrier Reef. Organic carbon averaged from 3.4 to 4.7 mg g-1, organic nitrogen from 0.20 to 0.31 mg g-1 and muramic acid from 1.4 to 3.3�g g-1 dry weight of surface sandy sediments. Bacterial biomass, determined by muramic acid measurements, averaged 3-8% of organic carbon in the sediments blue-green algae accounted for 3-7% of muramic acid. Significantly higher values of organic carbon and nitrogen and muramic acid were found in foregut contents of the holothurians, indicating selective feeding on organically rich components of the sediment. Carbon values were 16-34% higher in the foregut than in the sediment. nitrogen values 35-111% higher and muramic acid values 33-300% higher. These values indicate that bacteria and nitrogenous components of the organic matter were selectively eaten. Values for organic carbon and nitrogen and muramic acid were generally lower in the hindgut than in the foregut, due to digestion and assimilation. Assimilation efficiencies averaged 30% for organic carbon, 40% for organic nitrogen and 30-40% for muramic acid (bacteria). Detritus (non-living matter) probably constituted 60-80% of the organic matter in the sediment and thus the food of the holothurians.
Publisher: Elsevier BV
Date: 03-1995
Publisher: Elsevier BV
Date: 12-2000
DOI: 10.1016/S0167-7012(00)00207-4
Abstract: A rapid and effective method for the direct extraction of high molecular weight lifiable DNA from two coral reef sediments was developed. DNA was lified by the polymerase chain reaction (PCR) using 16S rDNA specific primers. The licons were digested with HaeIII, HinP1I and MspI and separated using polyacrylamide gel electrophoresis and silver staining. The resulting lified ribosomal DNA restriction analysis (ARDRA) patterns were used as a fingerprint to discern differences between the coral reef sediment s les. Results indicated that ARDRA is an effective method for determining differences within the bacterial community amongst different environmental s les.
Publisher: Elsevier BV
Date: 06-1991
Publisher: CSIRO Publishing
Date: 1977
DOI: 10.1071/MF9770113
Abstract: The proventriculus contents have been analysed in five species of penaeid prawns, Penaeus plebejus, P. esculentus, P. merguiensis, Metapenaeus bennettae and Trachypenaeus fulvus. Measurements of organic and inorganic carbon, protein and bacterial biomass show that these prawns are omnivores, feeding in an opportunistic manner. Most proventriculus contents contained about 100-150 mg organic C/g dry weight, of which 10-20% was bacterial C. The muddy sediments, over which the prawns were feeding, contained from 6 to 30 mg C/g dry weight with 6-16 % bacterial C. A sandy seagrass flat contained 2 mg C/g dry weight with 30% bacterial C. Detritus was sometimes the main food item, bacteria constituting up to 30 % of organic C in the proventriculus. Foraminifera, bivalves and crustaceans were important food items in some prawns. Low bacterial biomass, coupled with high CaCO3 and high protein content (about 40 % of organic matter) indicate that the fragments of animal skeletons are from live prey eaten by the prawns. Little difference was noted between species of prawns in their food preferences.
Publisher: Wiley
Date: 09-1973
Publisher: Springer Science and Business Media LLC
Date: 1975
DOI: 10.1007/BF00347474
Publisher: Springer Science and Business Media LLC
Date: 03-1985
DOI: 10.1007/BF00393250
Publisher: Elsevier BV
Date: 03-1970
Publisher: Elsevier BV
Date: 1997
Publisher: CSIRO Publishing
Date: 1990
DOI: 10.1071/MF9900785
Abstract: The growth rates and productivity of bacteria in the communities living on hard limestone substrate and sand were determined from the rates of incorporation of tritiated thymidine into DNA. Two reefs in the southern Great Barrier Reef, around Heron Island and One Tree Island, were studied during summer (January 1986). The specific growth rates varied on a diel cycle, being slowest at night, in both sand and hard substrate. They ranged from 0.005 h,-1 at night to 0.025 h-1 during the day in sand and from 0.002 to 0.01 h-1 in hard substrate. Productivity was also greater during the day than at night, ranging from 1 mg C m-2 h-1 at night to 5.5 mg C m-2 h-1 during the day in sand and from 0.5 to 2 mg C m-2 h-1 in hard substrate. Values were similar for both islands. The increase of four- to five-fold in bacterial growth rates in the sand and hard substrate on Heron Island during the daytime indicates that the heterotrophic bacteria rely mostly on organic matter exuded from the algae with which they are associated.
Publisher: Springer Science and Business Media LLC
Date: 1977
DOI: 10.1007/BF00345531
Publisher: Elsevier BV
Date: 05-1997
Publisher: Elsevier BV
Date: 07-1991
Publisher: CSIRO Publishing
Date: 1993
DOI: 10.1071/MF9930117
Abstract: Rates of acetylene reduction in seagrass communities in the Gulf of Carpentaria were determined in intact cores of sediment and seagrass and in slurries. Short-term incubations and three different methods were used to ensure that results could be reliably converted to rates of nitrogen fixation. At Groote Eylandt, values ranged from 16 to 47 mg N m-2 day-1 in a Syringodium isoetifolium community and from 13 to 19 mg N m-2 day-1 on a reef flat with Thalassia hernprichii. At Weipa, mean rates of nitrogen fixation were 25 mg N m-2 day-1 in an Enhalus acoroides community and 20 mg N m-2 day-1 on a mud bank below mangroves. About 5% of fixation was due to epiphytes on the seagrass leaves, and 8% of fixation associated with the Syringodium isoetifolium community occurred in washed roots and rhizomes the remainder was due mostly to bacteria in the sediment. Nitrogen fixation supplied 8 to 16% of the nitrogen requirements of the plants.
Publisher: Microbiology Society
Date: 08-1968
Publisher: Elsevier BV
Date: 05-1985
Publisher: Informa UK Limited
Date: 1985
DOI: 10.1080/01490458509385919
Abstract: Different methods for measuring the rates of processes mediated by bacteria in sediments and the rates of bacterial cell production have been compared. In addition, net production of the seagrass Zostera capricorni and bacterial production have been compared and some interrelationships with the nitrogen cycle discussed. Seagrass productivity was estimated by measuring the plastochrone interval using a leaf stapling technique. The average productivity over four seasons was 1.28 +/- 0.28 g C m-2 day-1 (mean +/- standard deviation, n = 4). Bacterial productivity was measured five times throughout a year using the rate of tritiated thymidine incorporated into DNA. Average values were 33 +/- 12 mg C m-2 day-1 for sediment and 23 +/- 4 for water column (n = 5). Spatial variability between s les was greater than seasonal variation for both seagrass productivity and bacterial productivity. On one occasion, bacterial productivity was measured using the rate of 32P incorporated into phospholipid. The values were comparable to those obtained with tritiated thymidine. The rate of sulfate reduction was 10 mmol SO4(-2) m-2 day-1. The rate of methanogenesis was low, being 5.6 mg CH4 produced m-2 day-1. A comparison of C flux measured using rates of sulfate reduction and DNA synthesis indicated that anaerobic processes were predominant in these sediments. An analysis of microbial biomass and community structure, using techniques of phospholipid analysis, showed that bacteria were predominant members of the microbial biomass and that of these, strictly anaerobic bacteria were the main components. Ammonia concentration in interstitial water varied from 23 to 71 micromoles. Estimates of the amount of ammonia required by seagrass showed that the ammonia would turn over about once per day. Rapid recycling of nitrogen by bacteria and bacterial grazers is probably important.
Publisher: Wiley
Date: 07-1990
Publisher: Springer Science and Business Media LLC
Date: 1982
DOI: 10.1007/BF00396917
Publisher: Elsevier BV
Date: 08-1970
DOI: 10.1016/0005-2728(70)90165-9
Abstract: Levosimendan improves clinical and hemodynamic parameters exerting an anti-inflammatory and antiapoptotic effect in decompensated heart failure. The aim of this study was to evaluate the effects of levosimendan on LV torsion, plasma levels of NT-proBNP and on the balance between pro-inflammatory (TNF-α, IL-6) and anti-inflammatory cytokines (IL-10). We enrolled 24 patients (age 62 ± 7 years) with acute HF, NYHA class IV and severe LV dysfunction. All patients underwent transthoracic echocardiography using two-dimensional speckle tracking analysis to detect LV twist angle (LVTA), at baseline and 1 week after treatment with levosimendan infusion. Biochemical parameters (pro-BNP, IL-6, IL-10, TNF-α) were determined by enzyme-linked immunosorbent (ELISA). After one week, we observed an improvement in LV function especially in LVTA (4.15 ± 2.54 vs 2.9 ± 2.1 p 20%) and BNP (Δ > 40%), LVEF (Δ > 10%) and LVTA (Δ > 20%) (O.R. 1.77, 95% C.I. 1.11-2.83 O.R. 1.49, 95% C.I. 1.08-2.67 O.R. 1.66, 95% C.I. 1.10-2.74, respectively, confirmed p, all < 0.01 by Hosmer-Lemeshov confirmation and the formal test for interaction). Levosimendan exerts a hemodynamic effect by improving EF and LV torsion in patients with acute HF in association with a positive effect on the balance between pro and anti-inflammatory cytokines.
Publisher: Springer Science and Business Media LLC
Date: 03-1985
DOI: 10.1007/BF00393249
Publisher: Elsevier BV
Date: 04-1986
Publisher: Springer Science and Business Media LLC
Date: 31-12-2019
Publisher: Elsevier BV
Date: 04-1990
Publisher: Geological Society of London
Date: 1990
Publisher: CSIRO Publishing
Date: 1981
DOI: 10.1071/MF9810245
Abstract: The food of seven species of penaeid prawns from the Gulf of Carpentaria consists predominantly of Foraminifera, small molluscs, crustaceans and polychaetes. Measurements of organic and inorganic carbon, organic nitrogen and bacterial biomass were made. Foregut contents of adult prawns contained between 72 and 223 mg organic carbon/g dry wt. Protein constituted between 43 and 64% of the organic matter. Approximate assimilation efficiencies of food in prawns caught in the gulf, determined for four species, varied from 48 to 77% of organic carbon and from 42 to 77% of organic nitrogen. The food of juvenile Penaeus merguiensis was examined for two growing seasons. In the 1976-1977 season the foregut contents contained a mean of 41 mg organic nitrogen /g dry wt and 181 mg organic carbon /g dry wt. In the 1977-1978 season, significantly lower proportions of organic nitrogen and carbon were eaten, viz, 21 mg organic nitrogenlg dry wt and 101 mg organic carbon /g dry wt. Improved assay procedures for muramic acid have shown that bacteria are less important in the food of prawns than previously reported. Bacteria constituted less than 2% of the organic matter in the adults of all species, but in many juvenile P. merguiensis bacteria were more important, constituting up to 14% of organic matter.
Publisher: Informa UK Limited
Date: 1983
Publisher: Springer Science and Business Media LLC
Date: 1986
DOI: 10.1007/BF00569443
Publisher: Springer Science and Business Media LLC
Date: 1986
DOI: 10.1007/BF00569442
Publisher: Springer Science and Business Media LLC
Date: 1979
DOI: 10.1007/BF00423064
Publisher: Elsevier BV
Date: 07-1987
Publisher: Elsevier BV
Date: 05-1998
Publisher: Springer Science and Business Media LLC
Date: 09-1986
DOI: 10.1007/BF02011169
Publisher: Michigan State University Press
Date: 07-2012
DOI: 10.1080/14634988.2012.705775
Abstract: The impact of waste on the coastal environment from urban sources and the agriculture, manufacturing and aquaculture industries can be mitigated by the use of appropriate microbes either in idually or in consortia with plants. Aquaculture—coastal land-based and estuarine or bay cage aquaculture—and urban sewage and industrial organic wastes are particularly amenable to microbial technologies. Several criteria must be applied to ensure success. Appropriate species for microbial technology, i.e. microbes that are natural to, or integrate easily into, the natural ecological communities and provide the desired beneficial actions, have to be selected and produced at a cost that is acceptable to the end users. The microbes have to be added at a high enough population density to compete with the natural flora in the treatment sites. Bacteria that carry genes for antibiotic resistance and disease virulence must not be used in sites where they could affect not only human, but also fish and shrimp health safety checks must be made during selection and production processes. Microbial technologies are now being used widely in the field of aquaculture, where an obvious cost-benefit is seen at harvest. Microbial technologies can lower energy and other costs of treating of urban and industrial wastes and assist in meeting regulatory targets for effluent quality.
No related grants have been discovered for David J.W. MORIARTY.