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Water,salt and nutrient fluxes of tropical tidal salt flats 总被引：2，自引：0，他引：2
The water budget of a tropical tidal salt flat in dry tropical Australia has been studied with particular emphasis on estimating the groundwater fluxes. Salt was used as a passive tracer to determine some of these fluxes. Groundwater salt accumulation (or loss) was less than 1 kg/m3/month. Surface water leaving the flat at a higher salt concentration than flood water causes a net outwelling of salt of between 0.4 and 1 kg/m2/month. Evaporation from the salt flat was estimated to be 70 mm/month. Using these measurements and a simple model of the groundwater flows, it is concluded that the groundwater loss is less than 40 mm/month. The accuracy of the salt budget was insufficient to rule out the possibility that the net groundwater motion was upwards. Measurements of Si and PO_4 fluxes indicated that the net outwelling due to surface water flows were respectively 3 mmole/m2/month and 0.014 mmole/m2/month. A net groundwater loss of 10 mm would produce a similar magnitude outwelling due to groundwater discharge. The mangrove-fringed tropical tidal salt flats are the source of large quantities of nutrients that are released to the near-shore zone. 相似文献
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Assessing sediment removal capacity of vegetated and non-vegetated settling ponds in prawn farms 总被引：8，自引：0，他引：8
Halmar Halide Peter V. Ridd Eric L. Peterson David Foster 《Aquacultural Engineering》2003,27(4):295-314
Sediment removal capacity is assessed for a constructed mangrove wetland, and a non-vegetated settling pond that are both used for filtering water in tropical aquaculture. The assessment is performed through sediment budget analysis using data of suspended sediment concentration collected from optical backscatter sensors. The sensors were deployed at the pond's inlet and outlet. These data sets provide a measure of trapping efficiency of each pond with different flow regimes and settling areas. The tides influenced flow in the wetland but none was felt in the settling pond. The average trapping efficiency obtained for the vegetated and the non-vegetated ponds was (40±33) and (70±36)%, respectively. The deposition rate calculated for the vegetated and non-vegetated pond ranges between 13–174 g/m2 per h (average=63 g/m2 per h) and 10–19 g/m2 per h (average=14 g/m2 per h), respectively. The efficiency of vegetated and non-vegetated ponds is likely to be improved by decreasing the aspect ratio (length/width) from the current value of 6 to 1 and of 5 to 1, respectively. 相似文献
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Evaporation over a tropical tidal salt flat 总被引：1，自引：0，他引：1
Measurements of temperature, wind speed and humidity within 6 mof the surface of a mangrove-fringed tidal tropical salt flatwere performed. Using the aerodynamic method, this data was usedto infer evaporation rates from the salt flat. For a few daysafter tidal inundation or rain, the salt flats were wet andevaporation rates of about 5×10-3 m day-1 prevailed. By 8 daysafter tidal inundation and with no rain, evaporation rates haddropped to less than 2×10-3 m day-1. The monthly evaporation ratewas about 7×10-2 m. This generates high salinity which, togetherwith surface temperatures exceeding 50°C, prevents colonisationof these areas by mangroves. 相似文献
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Spatial variations of groundwater salinity in a mangrove-salt flat system,Cocoa Creek,Australia 总被引：2，自引：0，他引：2
In this work the average groundwater salt concentration in a mangrove swamp and tropical salt flat system adjacent to Cocoa Creek near Townsville in North Queensland was measured with ground conductivity probes based on low frequency EMI (Electromagnetic Induction) and V-I (Resistivity) Methods. Transects of conductivity were measured with the conductivity probes and the spatial variations in the average groundwater salt concentration were determined from conductivity measurement with both probes. Lower concentrations occurred within mangrove forest as well as near the edges of the salt flats. Comparison of the results above 0.8 m and below 0.8 m showed that as depth increases, the concentrations become more homogeneous. For example at 0.4 m, salt concentrations across the salt flat vary from 75 g/l to 175 g/l where at 2 m the variation is only from about 75 g/l to 125 g/l. High lateral groundwater salt concentration gradients occured at the boundary between the mangroves and salt flat and also at the edges of the salt flat. Typical gradients were about 6 g/l/m and 2 g/l/m respectively. 相似文献
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