Upper tertiary rocks from the continental shelf and slope off Southern Hawkes Bay     

K. B. Lewis 《新西兰海洋与淡水研究杂志》2013,47(4):663-670

Sixteen rock samples were collected from the continental shelf and slope between Napier and Cape Turnagain, southern Hawkes Bay, most coming from offshore anticlinal ridges. Nine of the samples have a foraminiferal fauna of Upper Miocene and Pliocene age. The remainder cannot be dated, but most are probably of similar age. The foraminiferal. faunas are considered to have lived at depths ranging down to at least 1600 m deeper than the depth from which they were collected. Thus, the post‐depositional history of the samples includes tectonic uplift of similar magnitude since Upper Tertiary times. Because most of the samples arc very fine grained, unlike Recent sediments from ridges, it is suggested that the present regime of folding is largely post‐Pliocene in age.  相似文献   

The effect of membrane filtration on estimates of microbial ATP in New Zealand freshwaters     

R.D. Pridmore  C.W. Hickey  J. E. Hewitt 《新西兰海洋与淡水研究杂志》2013,47(3-4):311-315

Concentrations of microbial ATP in 15 New Zealand lakes were determined using 2 extraction techniques. ATP was found in both the paniculate (>0.45 μm) and dissolved (<0.45 μm) fractions of the water samples. Higher concentrations of paniculate ATP were obtained when ATP was extracted directly from freshwater samples rather than following pre‐concentration on to membrane filters. Recovery of particulate ATP declined with increasing volumes of sample filtered. The magnitude of the filtration effect varied unpredictably between lakes and within lakes with time. Corrections for the presence of dissolved ATP were necessary before estimates of particulate ATP could be made by the direct extraction technique. Concentrations of dissolved ATP up to 1.2 μg L^‐1 were observed. The direct extraction technique is recommended for more accurate determination of particulate ATP in New Zealand freshwaters.  相似文献   

Letters to the editor     

Malcolm Haddon  Robert C. Francis 《新西兰海洋与淡水研究杂志》2013,47(4):447-449

A preliminary scuba survey of oligotrophic Lake Rotoma in 1972 revealed a vegetation mainly composed of native hydrophytes in which exotics were at an early stage of colonisation. In 1973 the presence of species was recorded in 5708 quadrats (625 cm²) at 1 m intervals along a total of 50 line transects placed systematically around the lake. Water depth was measured, and quadrat cover and substrate type were subjectively estimated. Species frequency calculations showed that the dominant vegetation pattern was a characean meadow of Chara fibrosa f. acanthopitys (A.Br.) R.D.W., Nitella leptostachys var. leonhardii (R.D.W.) R.D.W., and N. pseudoflabellata var. mucosa (Nordst.) Bailey. The charophytes extended over a depth range of 1–17.5 m on a wide variety of substrates and gradients. Native vascular plants were absent from many transects, and had a depth range only from 0 to 4.5 m, with most occurring above 3.5 m. The Low Mixed Community, found in shallow water less than 1.25 m in depth at the northeast end of the lake, provided this area with a high species diversity. Exotic hydrophytes had established in many areas around the lake. The distribution of Lagarosiphon major (Ridley) Moss and Elodea canadensis Michx. appeared to coincide with boating access and fallen submerged trees over a depth range of 0–6.0 m, although much of the available habitat had not yet been exploited. Emergent species were most abundant within the southwest inlet and also in the lagoons surrounding the lake where sheltered conditions and shallow gradients prevail.  相似文献   

Limnology of Opal Lake     

D. J. Forsyth  A. L. MacKenzie 《新西兰海洋与淡水研究杂志》2013,47(3):279-283

Opal Lake, a cold, acid lake on the central volcanic plateau of the North Island, New Zealand, had an average pH of 4.3 and was highly eutrophic. The biota was less diverse than in neighbouring near‐neutral waters. Macrophytes were rare; phytoplankton were mainly represented by the Chlorophyceae, and there were only 4 zooplankton species. The mean standing crop of macroinvertebrates was 6240 per square metre; this was higher than in other eutrophic lakes in the region and comprised more than 98% chironomid larvae represented by 4 species. Molluscs were absent. The fauna was more diverse than in more acid lakes of the .central volcanic plateau.  相似文献   

Influence of the water layer upon the depth of ground radar investigations in freshwater reservoirs     

M. L. Vladov  A. M. Pyatilova 《Moscow University Geology Bulletin》2009,64(1):59-62

A number of problems associated with detailed investigation of subsurface geological structure below the bottoms of freshwater reservoirs (rivers, ponds, and lakes) arise during the study of the upper portions of geological sections. The present study is aimed at marginal estimation of the penetrating depth of ground radar investigations in freshwater reservoirs (based on bottom reflections), taking into account the complex nature of conductivity and its dependence upon the frequency under ideal conditions with no noise. The same method can be applied for estimating any given dynamic recording range.  相似文献   

Geologic and hydrologic settings for development of freshwater lenses in arid lands   总被引：2，自引：0，他引：2       下载免费PDF全文

Adam Milewski  Mohamed Sultan  Ahmad Al‐Dousari  Eugene Yan 《水文研究》2014,28(7):3185-3194

Satellite observations were used to test the validity of previously identified favourable conditions for the formation of freshwater lenses, identify additional potential occurrences, and model modern potential recharge in the Raudhatain Watershed (3696) in northern Kuwait. Favourable conditions include infrequent yet intensive precipitation events, drainage depressions to collect the limited runoff, and presence of conditions (e.g. high infiltration capacity) that promote groundwater recharge and preservation (e.g. underlying saline aquifer) of infiltrating groundwater as freshwater lenses floating over saline aquifer water due to differences in density. Specifically, the following field and satellite‐based observations were noted for the Raudhatain Watershed: (1) Over ~30 precipitation events were identified from the Tropical Rainfall Measuring Mission precipitation data (1998–2009); (2) slope is gentle (2 m/km), and the surface is largely (80%) covered by alluvial deposits with high infiltration capacities (up to 9 m/day); (3) no flows and long‐term ponding were reported at the watershed outlet or detected from Landsat thematic mapper images; (4) infiltration is high based on increases in soil moisture content (from an advanced microwave scanning radiometer) and vegetation index following large precipitation events; and (5) freshwater lenses that overlie highly saline [total dissolved solids (TDS): >35 000] unconfined aquifers underlying the watershed are absent in the southern regions, where infiltrating fresh water mixes with the less saline groundwater (TDS: <10 000). Twenty potential locations (size: 1 to 75 km²) for freshwater lens development were identified in northern Kuwait, and continuous rainfall–runoff models (Soil Water and Assessment Tool) were applied to provide a first‐order estimation of the average annual recharge in the watershed (127 × 10⁶ m³) and freshwater lenses (8.17 × 10⁶ m³). Results demonstrate the settings for enhanced opportunities for groundwater recharge, outline the amounts of and preservation conditions for the groundwater feeding the freshwater lenses, and highlight potential applications and locations of freshwater lenses in similar settings elsewhere in the Arabian Peninsula and beyond. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Atmospheric Nitrogen and Phosphorus Deposition at Three Sites in Nanjing,China, and Possible Links to Nitrogen Deposition Sources   总被引：1，自引：0，他引：1       下载免费PDF全文

Liying Sun  Yinglie Liu  Jinyang Wang  Mohammad Aslam K. Khalil  Jianwen Zou  Zhengqin Xiong 《洁净——土壤、空气、水》2014,42(11):1650-1659

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Fluctuation of Cadmium Load on a Tide‐Influenced Waterfront Lake in the Middle‐Lower Reaches of the Yangtze River          下载免费PDF全文

Hua Wang  Yiyi Zhou  Yong Pang  Xianmin Wang 《洁净——土壤、空气、水》2014,42(10):1402-1408

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Immobilisation of Pb and Zn in Soils Using Stabilised Zero‐valent Iron Nanoparticles: Effects on Soil Properties          下载免费PDF全文

María Mar Gil‐Díaz  Araceli Pérez‐Sanz  María Ángeles Vicente  María Carmen Lobo 《洁净——土壤、空气、水》2014,42(12):1776-1784

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Contrasting Phytoplankton Structure and Morphologically Based Functional Groups of Reservoirs That Differ in the Adjacent Surrounding          下载免费PDF全文

Elżbieta Wilk‐Woźniak  Judita Koreivienė  Jūratė Karosienė  Agnieszka Pociecha  Magdalena Strzesak  Wojciech Mróz 《洁净——土壤、空气、水》2016,44(6):638-647

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