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  • 1
    Electronic Resource
    Electronic Resource
    Detrital pathways in a coral reef lagoon (1992)
    Springer
    Marine biology 113 (1992), S. 363-372 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Coral reef lagoons have generally been regarded as sinks for organic matter exported from more productive reef front and reef flat zones. The object of this study was to examine the importance of detritus as a carbon source for benthic communities in the lagoon at Davies Reef, central Great Barrier Reef. We report the results of seasonal measurements, taken in 1986, of bacterial numbers and production, protozoan numbers, community primary production and respiration in the sediments of Davies Reef lagoon. Deposition rates of organic matter in the lagoon were also measured. Deposition rates (±1 SE) of carbon ranged from 9.2 (±1.5) to 140.7 (±10.3) mg Cm-2d-1. Deposition rates were highest in winter and spring, lowest in summer. Rates of bacterial production ranged from 4.7 (±0.2) pmol thymidine incorporated g-1 dry wt (DW) h-1 in winter to 23.5 (±1.0) pmol thymidine incorporated g-1 DW h-1 in spring. The number of ciliates ranged from 65 (±10) to 356 (±50) cm-3 through the year and the number of large (≥20 μm) flagellates from 38 (±7) to 108 (±16) cm-3. There were no clear relationships between the sediment organic content, detrital input or temperature and the rates of bacterial processes, community metabolism or the standing stocks of microbes in the lagoon. The relative significance of detritus and in situ primary production as sources of carbon in the lagoon varied with season. In summer and autumn, detritus was less important than primary production as a source of carbon (4 to 27% of total carbon input). In winter and spring, detritus input became more significant in supply of carbon to the sediments (32 to 67% of the total carbon input). The lagoon does not simply act as a sink for carbon exported from the reef flat. We calculate that only 5% of the net reef flat primary production reached lagoon sediments in summer, but nearly 40% in winter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349160
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  • 2
    Electronic Resource
    Electronic Resource
    Detrital pathways in a coral reef lagoon (1990)
    Springer
    Marine biology 104 (1990), S. 109-118 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Coral reef lagoons are generally regarded as zones of net heterotrophy reliant on organic detritus generated in more productive parts of the reef system, such as the seaward reef flat. The abundance and biomass of sediment infauna were measured seasonally for one year (1986) within the lagoon of Davies Reef, central Great Barrier Reef, to test the hypothesis that macrofaunal biomass and production of coral reef lagoons would decrease with distance from the reef flat and would change seasonally. In general, there were no simple relationships between infaunal standing stock or production and distance from the reef flat or season. Bioturbation by callianassid shrimps negatively affected the abundance of smaller infauna, suggesting a community limited by biogenic disturbance rather than by supply of organic material. Polychaetes and crustaceans were dominant amongst the smaller infauna (0.5 to 2mm) while larger animals (〉 2 mm) were mostly polychaetes and molluscs. Mean biomass of infauna at both sites and all seasons was 3 181 mg C m−2. The smaller animals (0.5 to 2 mm) contributed about 40% of total macrofaunal respiration and production although they represented only 15% of the total macrofaunal biomass. The biomass of macrofauna was about equal to that of the bacteria and meiofauna, while respiration represented 10 to 20% of total community respiration. Consumption by macrofauna accounts for only 3 to 11% of total organic inputs to sediment, with a further 14 to 17% being lost by macrofaunal respiration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01313164
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  • 3
    Electronic Resource
    Electronic Resource
    Vertical profiles of bacterial abundance, productivity and growth rates in coastal sediments of the central Great Barrier Reef lagoon (1992)
    Springer
    Marine biology 112 (1992), S. 657-663 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Vertical patterns of bacterial densities, productivity and specific growth rates in coastal muds, quartz sands and muddy sands of the central Great Barrier Reef lagoon were examined in summer (February) and autumn (May) 1988. Variations in these parameters with station location, sediment depth and season were complex, exhibiting significant main and interaction effects in most instances. Some trends were apparent despite the large and complex variations. Bacterial densities did not vary seasonally, ranging from 2.9 to 38.1×109 cells g-1 dry wt, averaged over sediment depth (0 to 20 cm) and seasons. Trend analysis revealed that densities decreased with increasing sediment depth. Bacterial production (tritiated thymidine incorporation into DNA) was high, ranging from 0.4 to 5.7 gCm-2 d-1 (integrated over 10 cm depth), as were specific growth rates (grand mean, μ=0.25 d-1; range=0.004 to 1.3 d-1). Both were generally higher in summer than in autumn. Vertical profiles of productivity and specific growth rates revealed actively growing bacterial assemblages down to 20 cm depth. Factors which may account for these very abundant and productive communities are: (1) subsurface accumulations of detritus exported from adjacent mangrove forests, and (2) physical disturbance from tidal scouring and severe climate (e.g. cyclones, wet-season floods). Disturbance events occur frequently enough to inhibit the development of highly sulphidic conditions, but stimulate production of bacterial types (aerobes, fermenters) capable of incorporating labelled thymidine into their DNA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00346184
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of monsoonal climate on sulfate reduction in coastal sediments of the central Great Barrier Reef lagoon (1995)
    Springer
    Marine biology 122 (1995), S. 497-502 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rates of sulfate reduction were measured during the spring dry and summer wet seasons of 1992 in shallow coastal sediments of the central Great Barrier Reef lagoon. In the dry season, sulfate reduction rates, integrated to 18–20 cm depth, ranged from 23.8 to 30.8 mmol S m-2 d-1. In the wet season, heavy monsoonal rains and wind-induced waves caused severe disturbance of sediments leading to less anoxic conditions, and to a 2- to 3-fold decline in rates of sulfate reduction (10.2 to 12.8 mmol S m-2 d-1). The percentage of reduced 35S recovered as acid-volatile sulfide (% AVSred) ranged from 15.8 to 44.9% in spring, and was significantly reduced at each station in summer (range 14.5 to 31.4%). An analysis of variance indicated that seasonality accounted for 31.5% of the total variance in total rates of sulfate reduction, with only 7.5% of the variance accounted for by depth into the sediment; there were no station differences. In both seasons, there were no clear patterns in the proportion of radiolabel incorporated into the AVS and chromium-reducible sulfur (CRS) pools with depth into the sediment. These results are contrary to the seasonal patterns and pathways of sulfate reduction in temperate coastal sediments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350884
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  • 5
    Electronic Resource
    Electronic Resource
    Colonization of meiobenthos in oil-contaminated subtidal sands in the lower Chesapeake Bay (1983)
    Springer
    Marine biology 72 (1983), S. 325-335 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In-situ manipulative experiments were conducted over a 3-month period (May–August 1980) to examine the rate at which meiobenthos colonizes oiled and untreated azoic fine sands at a shallow subtidal site in the lower York River, Virginia. Three concentrations of fresh Prudhoe Bay crude oil were added to sediments: 100, 2 500 and 10000 mg oil kg-1 dry wt sediment. Untreated azoic and natural sediments served as controls. Within 16 d, meiofauna densities in all treatments were comparable to natural populations in surface oxidized sediments, but densities fluctuated greatly during the remainder of the sampling period. Nematodes slowly colonized the subsurface anoxic sediments below the redox potential discontinuity (RPD); some less common species did not significantly recover below the RPD in the two more heavily oiled treatments. Analysis of nematode community composition by reciprocal averaging ordination and numerical classification revealed generally lower abundances, but no distinct differences, in species composition in the oiled substrates as compared to untreated and natural community controls. Ordination of sequential samples suggested that the nematode species assemblages in the untreated controls fully recovered from these small-scale disturbances by 90 d. Life history characteritics and frequent tidal transport combine to make estuarine meiobenthos highly resilient following disturbance. Contrary to prior recolonization studies, a successional sequence was found for the colonizing nematodes which may be analogous to models of macrobenthic colonization (e.g. McCall, 1975). The comesomatid nematode Sabatieria pulchra, which is frequently dominant in polluted sediments, colonized relatively late in the experiment. Consequently, stress resistance and resilience may not be as coincident in meiofauna as in macrofauna because of differences in factors affecting their dispersal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00396839
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  • 6
    Electronic Resource
    Electronic Resource
    Intertidal zonation and seasonality of meiobenthos in tropical mangrove estuaries (1987)
    Springer
    Marine biology 95 (1987), S. 447-458 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Intertidal zonation and seasonality of tropical meiobenthic communities were examined within five mangrove estuaries along the northeastern coast (Cape York peninsula) of Australia from May 1985 to January 1986. Partial correlation analysis revealed that environmental cues such as temperature and sediment granulometry were the most important factors regulating the zonation patterns of meiofauna. Seasonality was greatly influenced by monsoonal rains. During austral summer, prolonged monsoonal rains occurred along the coast north of 18°S latitude (Hinchinbrook Island), resulting in increased river discharge and scouring of surface silts and clays, organic matter and bacteria from most tidal sediments. Despite scouring, meiofaunal densities increased in the summer wet season, probably due to warmer temperatures and the high resilience of meiobenthos to sediment disturbance. In mangrove sediments not subjected to torrential rains (Hinchinbrook Island), meiofaunal densities were highest in austral autumn and winter (sediment temperature: 23 to 27°C) and lowest in austral spring and summer (28° to 40°C). Turbellarians were the dominant meiofaunal group, accounting for 58 to 67% of total faunal densities which generally decreased with elevation in all of the estuaries. Meiofauna in tropical Australian mangroves, as in other organic-rich muds and in coral reefs, appear to exert little impact on microbial standing stocks when intercorrelated variables are accounted for. The abundances of hard-bodied meiofauna were low compared with temperate communities, lending further support to Moore's (1972) contention that tropical intertidal communities are subjected to greater physical stress than their temperate counterparts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409574
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  • 7
    Electronic Resource
    Electronic Resource
    Water column production and nutrient characteristics in mangrove creeks receiving shrimp farm effluent (2002)
    Oxford, UK : Blackwell Science, Ltd
    Aquaculture research 33 (2002), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Water column processes in undisturbed mangrove creeks and in creeks receiving effluent from shrimp farms in North Queensland, Australia, were studied. Small scale discharges into tidal creeks did not elevate dissolved nutrient concentrations compared with non-impacted creeks, but did elevate concentrations of particulate nutrients, chlorophyll and suspended solids proximal to the site of the effluent discharge. Rates of primary and bacterial production downstream from the discharge exceeded rates in the shrimp ponds because of the synergistic effects of turbulent mixing and eutrophication. In the lower reaches of the mangrove creeks and immediately offshore, standing stocks of particulate material and rates of primary and bacterial production were within the range of values found in non-discharge areas. Our results suggest that water column production by phytoplankton and bacteria strips nutrients from shrimp farm effluent and repackages them in more bioavailable forms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1355-557X.2001.00644.x
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  • 8
    Electronic Resource
    Electronic Resource
    Carbon and nitrogen budgets in shrimp ponds of extensive mixed shrimp–mangrove forestry farms in the Mekong delta, Vietnam (2000)
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 31 (2000), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Mass balance estimates of carbon and nitrogen flux through two extensive shrimp ponds in the Mekong delta, Vietnam, were constructed to identify major sources and sinks of organic matter potentially available for shrimp production. Nutrient transformations in the sediments were measured to further assess rates of decomposition and burial and quality of organic matter. Tidal exchange was the major pathway for inputs and outputs of carbon and nitrogen in both ponds, with net primary production, nitrogen fixation and precipitation being minor inputs. No fertilizers or artificial feeds were added to either pond. The nutrient budgets identified burial and respiration as the next most important outputs after tidal exchange losses of particulate and dissolved carbon and nitrogen. There was no measurable denitrification in either pond, and volatilization was negligible. Mineralization efficiency of carbon in the water column was high (〉 100%) in pond 23 reflecting rapid respiration rates; efficiency was lower (36%) in pond 12 waters. Mineralization efficiency of sediment nutrients averaged 34% for C and 41% for N in the pond with a higher annual shrimp yield (pond 12); lower mineralization efficiencies (11% for C, 10% for N) were calculated for the lower yield pond (pond 23). High burial efficiencies for both C (66–89%) and N (59–90%) in the sediments of both ponds suggest that little organic matter was shunted into biological production. Conversion efficiency for shrimp averaged 16% for C and 24% for N from pond 12, and 6% for C and 18% for N from pond 23. The high quantity but low quality of organic matter entering the ponds coupled with other factors, such as poor water quality, limits shrimp productivity. On average, nutrient outputs were greater than inputs in both ponds. This imbalance partly explains why shrimp yields are declining in these ponds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2109.2000.00457.x
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  • 9
    Electronic Resource
    Electronic Resource
    Role of riverine mangrove forests in organic carbon export to the tropical coastal ocean: A preliminary mass balance for the Fly Delta (Papua New Guinea) (1995)
    Springer
    Geo-marine letters 15 (1995), S. 134-139 
    Details
    ISSN: 1432-1157
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract A preliminary mass balance for organic carbon in the Fly Delta was constructed to determine the quantity and source of organic matter exported to the adjacent Gulf of Papua and Coral Sea. Total organic carbon input from the river to the delta is 1.7 × 1012 g C yr−1, composed almost equally of DOC and POC. Benthic and pelagic respiration in the delta accounts for 1.0 × 1012 g C yr−1, being a major sink for riverine organic carbon. Benthic flux measurements indicate that one third of all DOC entering the delta is taken up by sediments there. Mangrove forests export 〉3.0 × 1011 g C yr−1 POC to delta waters, and it appears that this mangrove carbon is exported to the adjacent shelf and deep sea. These results imply that little of the riverine supply of organic carbon reaches the Gulf of Papua, but that mangrove forests in the Fly and other rivers lining the gulf play a major role in river-shelf carbon exchange.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01204454
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  • 10
    Electronic Resource
    Electronic Resource
    Factors regulating benthic food chains in tropical river deltas and adjacent shelf areas (1995)
    Springer
    Geo-marine letters 15 (1995), S. 145-152 
    Details
    ISSN: 1432-1157
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Benthic food chains of the Amazon (Brazil) and Fly (Papua New Guinea) river deltas and adjacent shelves are compared. Abundance patterns of the major trophic groups (bacteria, meiofauna, and macroinfauna) are similar between regions, with very low densities, or the absence of benthos, within and near the deltas. For muds in the more quiescent areas, benthic abundance and productivity are highest, commonly coinciding with maximum pelagic primary production. Episodes of physical disturbance, erratic food supply, and dilution of river-derived, particulate organic matter foster the development of opportunistic benthic communities of variable diversity and low biomass, dominated by bacteria. These pioneering assemblages are the main food of penaeid shrimp, which dominate the demersal trawl fisheries of both fluvial-dominated regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01204456
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