Winter temperature structure in lakes atiamuri and ohakuri,New Zealand     

J. Irwin  R. A. Heath 《新西兰海洋与淡水研究杂志》2013,47(4):492-496

Temperature observations were collected in July 1967 on two artificial lakes on the Waikato River, North Island, New Zealand. Tributary arms of the lakes had surface temperatures up to 3–7 °c lower than the main arms, and sinking of this cooler water lead to vertical temperature gradients in the main arms, which would otherwise be nearly isothermal.  相似文献   

Reproducibility of river water quality measurements: inter-agency comparisons for quality assurance     

Rob Davies-Colley  Juliet Milne  Mark W. Heath 《新西兰海洋与淡水研究杂志》2019,53(3):437-450

We assessed the reproducibility of river state-of-environment (SoE) water quality measurements in the Wellington Region, New Zealand (NZ). Field staff from GWRC and NIWA conducted 29 side-by-side water sampling and in-situ measurements at six river sites of diverse water quality for 12 variables measured routinely in river SoE monitoring across NZ. Field measurements of water temperature, dissolved oxygen, electrical conductivity and visual clarity agreed closely with strong numerical similarity (within 10%). Numerical similarity ranged widely for laboratory measurements, from strong for nitrate-nitrite-nitrogen to weak for turbidity, dissolved reactive phosphorus, and ammoniacal-nitrogen. Numerical agreement was very weak for laboratory pH (which is problematic) and E. coli–which is ‘tolerable’ for many applications given good correlation (R?=?0.94) over a 2000-fold concentration range. The findings of our inter-agency comparison have contributed to quality assurance recommendations in the NZ National Environmental Monitoring Standard (NEMS) for water quality.  相似文献   

Ethics and Hydrogeology     

Ralph C. Heath 《Ground water》1998,36(6):865-866

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Chrysophycean cysts in Sierra Nevada (California) lake sediments: paleoecological potential     

Heath J. Carney  Mark C. Whiting  Katharine E. Duff  Donald R. Whitehead 《Journal of Paleolimnology》1992,7(1):73-94

Thirty-three lakes in the Sierra Nevada range of California were investigated as part of a paleoecological study of the potential effects of acid deposition on sensitive lake/watershed ecosystems. Chrysophyte cysts from surface sediment samples were analyzed and compared with data on pH and alkalinity. This paper identifies the twenty-five dominant chrysophyte cyst taxa and provides information on their morphology, abundance, distribution and ecology.Chrysophycean cysts were generally abundant and well-preserved in lake sediments of our study sites. Twelve taxa occurred in more than twenty of the thirty-three lakes; these taxa were often quite abundant. In contrast, only nine taxa occurred in ten or fewer lakes. Abundance Weighted Mean (AWM) pH varied from 6.45 to 8.34 and AWM alkalinity varied from 46 to 588 eq/L. We delineated pH preference categories, based on AWM pH values and frequency diagrams of cyst abundance vs. lake-water pH. We classified five taxa as acidophilous, nine as circumneutrals, six as alkaliphilous and five as indifferent. Given that the cyst types differ greatly in their abundance relative to pH and alkalinity, it is clear that they have potential for paleolimnological studies of Sierra lakes biogeochemistry.  相似文献   

The rate of growth of density perturbations in simple big-bang model universes     

D. Edwards  D. Heath 《Astrophysics and Space Science》1976,41(1):183-193

In this paper we present exact solutions to the density perturbation equation derived by Bonnor for the cases where = _c ,k=1 and = – _c ,k=–1. The solutions when =0,k=1 and =0,k=–1 have been previously published. Using these solutions a quantitative analysis has been carried out that has enabled us to estimate the size of the fluctuations that must be postulated at decoupling in order to explain the formation of the galaxies in these model universes.  相似文献   

Small-scale electrical resistivity tomography of wet fractured rocks     

LaBrecque DJ  Sharpe R  Wood T  Heath G 《Ground water》2004,42(1):111-118

This paper describes a series of experiments that tested the ability of the electrical resistivity tomography (ERT) method to locate correctly wet and dry fractures in a meso-scale model. The goal was to develop a method of monitoring the flow of water through a fractured rock matrix. The model was a four by six array of limestone blocks equipped with 28 stainless steel electrodes. Dry fractures were created by placing pieces of vinyl between one or more blocks. Wet fractures were created by injecting tap water into a joint between blocks. In electrical terms, the dry fractures are resistive and the wet fractures are conductive. The quantities measured by the ERT system are current and voltage around the outside edge of the model. The raw ERT data were translated to resistivity values inside the model using a three-dimensional Occam's inversion routine. This routine was one of the key components of ERT being tested. The model presented several challenges. First, the resistivity of both the blocks and the joints was highly variable. Second, the resistive targets introduced extreme changes the software could not precisely quantify. Third, the abrupt changes inherent in a fracture system were contrary to the smoothly varying changes expected by the Occam's inversion routine. Fourth, the response of the conductive fractures was small compared to the background variability. In general, ERT was able to locate correctly resistive fractures. Problems occurred, however, when the resistive fracture was near the edges of the model or when multiple fractures were close together. In particular, ERT tended to position the fracture closer to the model center than its true location. Conductive fractures yielded much smaller responses than the resistive case. A difference-inversion method was able to correctly locate these targets.  相似文献   

Alterations in tissue water balance and adenylates of bluegill (Lepomis macrochirus) exposed to copper     

Alan G. Heath 《Marine environmental research》1984,14(1-4)

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Community volunteer assessment of recreational water quality in the Hutt River,Wellington     

Amanda E. Valois  Juliet R. Milne  Mark W. Heath  Rob J. Davies-Colley  Emily Martin  Rebecca Stott 《新西兰海洋与淡水研究杂志》2020,54(2):200-217

ABSTRACT

Water is an important component of many recreational opportunities and New Zealand invests significant resources in recreational water quality (RWQ) monitoring to assess risks to public health. However, monitoring primarily focuses on microbiological hazards and RWQ is considerably broader than this. The goal of this study was to take a comprehensive approach to evaluating RWQ while exploring the potential for greater public involvement in monitoring. A popular river swimming site was co-monitored weekly by volunteers and a council field officer. The attributes monitored–water temperature, visual clarity, benthic cyanobacteria and filamentous periphyton cover, E. coli and rubbish–were identified from a volunteer workshop. There was good concordance between volunteer and council data suggesting that volunteer measurements can be considered reliable. This highlights the potential for volunteers, with professional support, including training and quality assurance, to extend council RWQ surveillance to additional monitoring sites while improving public engagement on water management.  相似文献   

Comparative ecology of over-wintering Calanus finmarchicus in the northern North Atlantic, and implications for life-cycle patterns     

Heath  Michael R; Boyle  Peter R; Gislason  Astthor; Gurney  William S.C; Hay  Stephen J; Head  Erica J.H; Holmes  Steven; Ingvarsdottir  Anna; Jonasdottir  Sigrun H; Lindeque  Pennie; Pollard  Raymond T; Rasmussen  Jens; Richards  Kelvin; Richardson  Katherine; Smerdon  Gary; Speirs  Douglas 《ICES Journal of Marine Science》2004,61(4):698-708

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Ecosystem models of Scottish sea lochs for assessing the impact of nutrient enrichment   总被引：1，自引：0，他引：1  

Ross  A. H.; Gurney  W. S. C.; Heath  M. R. 《ICES Journal of Marine Science》1993,50(4):359-367

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