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Lirman D Gracias NR Gintert BE Gleason AC Reid RP Negahdaripour S Kramer P 《Environmental monitoring and assessment》2007,125(1-3):59-73
The recent decline in the condition of coral reef communities worldwide has fueled the need to develop innovative assessment
tools to document coral abundance and distribution rapidly and effectively. While most monitoring programs rely primarily
on data collected in situ by trained divers, digital photographs and video are used increasingly to extract ecological indicators, provide a permanent
visual record of reef condition, and reduce the time that divers spend underwater. In this study, we describe the development
and application of a video-based reef survey methodology based on an algorithm for image registration and the estimation of
image motion and camera trajectory. This technology was used to construct two-dimensional, spatially accurate, high-resolution
mosaics of the reef benthos at a scale of up to 400 m2. The mosaics were analyzed to estimate the size and percent cover of reef organisms and these ecological indicators of reef
condition were compared to similar measurements collected by divers to evaluate the potential of the mosaics as monitoring
tools. The ecological indicators collected by trained divers compared favorably with those measured directly from the video
mosaics. Five out of the eight categories chosen (hard corals, octocorals, Palythoa, algal turf, and sand) showed no significant differences in percent cover based on survey method. Moreover, no significant
differences based on survey method were found in the size of coral colonies. Lastly, the capability to extract the same reef
location from mosaics collected at different times proved to be an important tool for documenting change in coral abundance
as the removal of even small colonies (<10 cm in diameter) was easily documented. The two-dimensional video mosaics constructed
in this study can provide repeatable, accurate measurements on the reef-plot scale that can complement measurements on the
colony-scale made by divers and surveys conducted at regional scales using remote sensing tools. 相似文献
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G. J. Duffy BE PhD MAIE R. D. Lanauze BE PhD MAIE J. W. Kable BSc 《Environmental geochemistry and health》1981,3(4):103-110
All Australian coal for export is washed — that is, the low-grade high-ash material is separated out and disposed of at the washery site. The coarse rejects are generally placed in embankments and the tailings are pumped into settling ponds. These methods of waste disposal can create environmental problems. In addition, they represent a significant energy loss, because about one-third of the waste material is combustible and is thus a potentially valuable source of energy. Laboratory studies at the CSIRO Division of Fossil Fuels at North Ryde, New South Wales, have shown that energy can be successfully recovered from washery wastes by the process of fluidized-bed combustion. A pilot fluidized-bed combustor, with a capacity of 2 tonnes/hour, is undergoing prolonged trial at the Clutha washery near Camden, New South Wales, in a joint project between the Joint Coal Board and CSIRO. The results from the pilot plant tests have provided the basis for a conceptual design and feasibility study for a full-scale tailings treatment plant. This study has indicated that fluidized-bed combustion:
- offers an environmentally attractive and economically competitive alternative to the disposal of tailings in settling ponds, and
- can be used to generate large quantities of energy from the wastes, reducing the energy lost in coal washing from around 16% to 6% of the coal mined.
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Tailings containing toxic qualities of heavy metals are a potential source of pollution. Stabilisation by vegetative methods have been found the most effective. In an attempt to vegetate tailings dams it has been noted that while certain milky latex containing plants can be grown without any preconditioning of the soil, almost any plant can be grown after proper conditioning. However, the plants grown there cannot be consumed by humans or cattle due to their high metal content. 相似文献
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