Literature Review and Model (COMET) for Colloid/Metals Transport in Porous Media   总被引：8，自引：0，他引：8  

William B. Mills  Sally Liu  Fred K. Fong 《Ground water》1991,29(2):199-208

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The evolution of tidal creek networks,mary river,northern Australia     

A. David Knighton  Colin D. Woodroffe  Kevin Mills 《地球表面变化过程与地形》1992,17(2):167-190

Tidal creek networks have in 50 years extended over 30 km inland across the coastal plains of the Mary River in northern Australia, invading freshwater wetlands and destroying the associated vegetation. The networks have grown at an exponential rate through a combination of main channel extension and tributary development, with concomitant widening of the creeks. A large tidal range, very small elevational differences over the plains, and the availability of preexisting channel lines (notably in the form of palaeochannels) have been major factors contributing to the rapid rate of expansion. Close parallels exist between these networks and terrestrial networks as regards modes of growth and planimetric properties. A channel is initiated when the diffuse flow of a seepage zone becomes concentrated through localized scour. Subsequent development is characterized by the rapid extension of long first-order channels, with most tributary addition occurring later. Model tests suggest that branching was more likely on exterior links in the early stages but that exterior and interior link branching became more equally likely through time. Although the headward limits of the main creeks seem to have been reached, tributary infilling will continue to progress upstream. Only in the most downstream parts is a stable drainage density being approached. The networks not only satisfy the laws of drainage network composition and the basic postulates of the random model but also depart from topologic randomness in similar ways to terrestrial networks. Both topologic and length properties have changed during evolution but largely at the link rather than network scale. The close correspondence with terrestrial networks may be due to the low relief and the relatively unconstrained nature of growth in which availability of space was the main determining factor.  相似文献   

Geology,alteration, and lithogeochemistry of the Hood volcanogenic massive sulfide (VMS) deposits,Nunavut, Canada     

Hannah K. Mills  Stephen J. Piercey  Trish Toole 《Mineralium Deposita》2016,51(4):533-556

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Estimating high resolution trawl fishing effort from satellite-based vessel monitoring system data   总被引：6，自引：0，他引：6  

Mills  Craig M.; Townsend  Sunny E.; Jennings  Simon; Eastwood  Paul D.; Houghton  Carla A. 《ICES Journal of Marine Science》2007,64(2):248-255

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Factors affecting the distribution of benthic macrofauna in estuaries contaminated by urban runoff     

Morrisey DJ  Turner SJ  Mills GN  Williamson RB  Wise BE 《Marine environmental research》2003,55(2):113-136

Contaminants derived from urban runoff have been shown to accumulate in estuarine sediments, reaching concentrations potentially capable of causing biological effects. Demonstration of effects, however, is difficult due to strong natural environmental gradients and the effects of past or present point-sources of contamination. We used multivariate methods to test two hypotheses relating to the effects of urban-derived contaminants on estuarine benthic communities. First, that patterns of distribution and abundance of benthic invertebrates in two urbanised estuaries would be different from those in two non-urbanised estuaries. Second, that the distributions of benthic invertebrates within and among the four estuaries would be related to those of urban-derived contaminants. Concentrations of contaminants were larger in estuaries with urbanised catchments and concentrations of Cu, Pb, Zn and DDT in some samples exceeded those at which biological effects may be expected to appear. Tests of differences in composition of benthic communities among estuaries showed that the two urban estuaries were not significantly different, but that they differed from both rural estuaries, which also differed from each other. Distributions of benthic invertebrates were significantly related to those of environmental variables, and were ordinated along axes that correlated with both natural environmental variables (nature of the sediment, position in estuary) and contaminants. Differences in faunas between the urban and non-urban estuaries were not, however, clear-cut and nor were relationships between faunal assemblages and environmental variables (including contaminants) consistent between two times of sampling.  相似文献   

Defining and detecting undesirable disturbance in the context of marine eutrophication   总被引：1，自引：0，他引：1  

Tett P  Gowen R  Mills D  Fernandes T  Gilpin L  Huxham M  Kennington K  Read P  Service M  Wilkinson M  Malcolm S 《Marine pollution bulletin》2007,55(1-6):282-297

An understanding of undesirable disturbance to the balance of organisms is needed to diagnose marine eutrophication as defined by EU Directives and OSPAR. This review summarizes the findings of the UK Defra-funded Undesirable Disturbance Study Team, which concluded that 'an undesirable disturbance is a perturbation of a marine ecosystem that appreciably degrades the health or threatens the sustainable human use of that ecosystem'. A methodology is proposed for detecting disturbance of temperate salt-water communities dominated by phytoplanktonic or phytobenthic primary producers. It relies on monitoring indicators of ecosystem structure and vigour, which are components of health. Undesirable disturbance can be diagnosed by accumulating evidence of ecohydrodynamic type-specific changes in: (i) bulk indicators; (ii) frequency statistics; (iii) flux measurements; (iv) structural indicators; and (v) indicator species. These are exemplified by (i) chlorophyll, transparency, dissolved oxygen, and opportunistic seaweed cover; (ii) HABs frequency; (iii) primary production; (iv) benthic and planktonic 'trophic indices'; (v) seagrasses and Nephrops norvegicus. Ecological Quality Objectives are proposed for some of these. Linking the diagnosis to eutrophication requires correlation of changes with nutrient enrichment. The methodology, which requires the development of a plankton community index and emphasizes the importance of primary production as an indicator of vigour, can be harmonized with the EU Water Framework Directive and OSPAR's Strategy to Combat Eutrophication.  相似文献   

Assessing the impact of nutrient enrichment in estuaries: susceptibility to eutrophication   总被引：3，自引：0，他引：3  

Painting SJ  Devlin MJ  Malcolm SJ  Parker ER  Mills DK  Mills C  Tett P  Wither A  Burt J  Jones R  Winpenny K 《Marine pollution bulletin》2007,55(1-6):74-90

The main aim of this study was to develop a generic tool for assessing risks and impacts of nutrient enrichment in estuaries. A simple model was developed to predict the magnitude of primary production by phytoplankton in different estuaries from nutrient input (total available nitrogen and/or phosphorus) and to determine likely trophic status. In the model, primary production is strongly influenced by water residence times and relative light regimes. The model indicates that estuaries with low and moderate light levels are the least likely to show a biological response to nutrient inputs. Estuaries with a good light regime are likely to be sensitive to nutrient enrichment, and to show similar responses, mediated only by site-specific geomorphological features. Nixon's scale was used to describe the relative trophic status of estuaries, and to set nutrient and chlorophyll thresholds for assessing trophic status. Estuaries identified as being eutrophic may not show any signs of eutrophication. Additional attributes need to be considered to assess negative impacts. Here, likely detriment to the oxygen regime was considered, but is most applicable to areas of restricted exchange. Factors which limit phytoplankton growth under high nutrient conditions (water residence times and/or light availability) may favour the growth of other primary producers, such as macrophytes, which may have a negative impact on other biological communities. The assessment tool was developed for estuaries in England and Wales, based on a simple 3-category typology determined by geomorphology and relative light levels. Nixon's scale needs to be validated for estuaries in England and Wales, once more data are available on light levels and primary production.  相似文献   

Diatom-based models for inferring past water chemistry in western Ugandan crater lakes     

Keely Mills  David B. Ryves 《Journal of Paleolimnology》2012,48(2):383-399

Diatom surface sediment samples and corresponding water chemistry were collected from 56 lakes across a natural conductivity gradient in western Uganda (reflecting a regional climatic gradient of effective moisture) to explore factors controlling diatom distribution. Here we develop a regional training set from these crater lakes to test the hypothesis that this approach, by providing more appropriate and closer analogues, can improve the accuracy of palaeo-conductivity reconstructions, and so environmental inferences in these lake systems compared to larger training sets. We compare this output to models based on larger, but geographically and limnologically diverse training sets, using the European Diatom Database Initiative (EDDI) database. The relationships between water chemistry and diatom distributions were explored using canonical correspondence analysis (CCA) and partial CCA. Variance partitioning indicated that conductivity accounted for a significant and independent portion of this variation. A transfer function was developed for conductivity (r _jack ² ?=?0.74). Prediction errors, estimated using jack-knifing, are low for the conductivity model (0.256 log₁₀ units). The resulting model was applied to a sedimentary sequence from Lake Kasenda, western Uganda. Comparison of conductivity reconstructions using the Ugandan crater lake training set and the East Africa training set (EDDI) highlighted a number of differences in the optima of key diatom taxa, which lead to differences in reconstructed values and could lead to misinterpretation of the fossil record. This study highlights issues of how far transfer functions based on continental-scale lake datasets such as the EDDI pan-African models should be used and the benefits that may be obtained from regional training sets.  相似文献   

‘Skinning a cat’: alternative models of representing temperature trends     

Terence C. Mills 《Climatic change》2010,101(3-4):415-426

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Estimating the diffuse attenuation coefficient from optically active constituents in UK marine waters   总被引：1，自引：0，他引：1  

M.J. Devlin  J. Barry  D.K. Mills  R.J. Gowen  J. Foden  D. Sivyer  N. Greenwood  D. Pearce  P. Tett 《Estuarine, Coastal and Shelf Science》2009

We report a study of the attenuation of submarine Photosynthetically Active Radiation (PAR) in relation to the concentrations of Optically Active Constituents (OACs) in a range of water types around the United Kingdom. 408 locations were visited between August 2004 and December 2005. The diffuse attenuation coefficient (K_d) was estimated from profiles of downwelling PAR. Concentrations of Suspended Particulate Matter (SPM) were measured gravimetrically and concentrations of phytoplankton chlorophyll (chl) were measured by fluorometrically. Chromophoric Dissolved Organic Matter (CDOM) was measured either by fluorescence or as its proxy, salinity.  相似文献