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21.
Across subtidal coasts of temperate Australasia, canopy–benthos associations are mostly understood from broadly defined studies of kelp forests within eastern Australia and north-eastern New Zealand. We tested the hypotheses that (1) benthic assemblages differ between monospecific stands of Ecklonia radiata and stands that comprise E. radiata mixed with other canopy-forming species, (2) patterns observed locally (i.e. within sites 1–10 km apart) match those observed among regions (>1,000 km apart) for which (3) eastern Australia and northern New Zealand are representative of other regions of temperate Australasia. Benthic assemblages almost always differed among monospecific, mixed, and open stands indicating that failure to distinguish between superficially similar habitats can lead to over-generalised conclusions about the ecology of kelp forests. Patterns of differences among stands did not change between western and southern Australia but differed from eastern Australia, and patterns from all regions were distinct from New Zealand (WA=SAEANZ). Whilst local patterns were complex, the major morphological groups that often characterise benthos (i.e. encrusting coralline algae and turf-forming algae) revealed patterns that could be related across space from local to regional scales. These findings demonstrate that knowledge about the configuration of canopy-forming species will improve confidence about the representativeness of results and that any local complexity need not impede searches for generality when the spatial limits of patterns are also understood.Communicated by M.S. Johnson, Crawley 相似文献
22.
Irving A. Singer John A. Frizzola Maynard E. Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(11):455-458
The rise of a hot cloud resulting from combustion of a solid propellant rocket fuel at ground level has been determined from lapse-time movies and visual aircraft observations. The field tests were conducted near the 420 foot meteorological tower under various atmospheric conditions. A method of predicting the maximum thermal rise of a cloud, based on source and meteorological parameters, is described. Comparisons with other theoretical formulations are presented. 相似文献
23.
James R. Mahoney Patricia M. Irving John L. Malanchuk 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1489-1496
On the following pages is an excerpt from the Overview and Summary (Part 1) of the recently published 300-page National Acid Precipitation Assessment Program (NAPAP) document* that describes the planned activities of the Program for the next two years. This document has been made available for public review and an open meeting was held on November 17 in Washington, D.C. to receive comments on it. The Plan will be revised following consideration of these comments and published in January 1989. 相似文献
24.
M Fernandes S Benger SK Sharma S Gaylard T Kildea S Hoare M Braley AD Irving 《Journal of environmental monitoring : JEM》2012,14(9):2399-2410
The definition of the spatial footprint of land-derived nutrient plumes is a key element to the design of initiatives to combat eutrophication in urbanised coastal regions. These plumes, however, are difficult to monitor because of their inherent high-frequency temporal and spatial variability. Biomonitoring with macroalgae provides time-integration of bioavailable nitrogen inputs through the measurement of δ(15)N signatures in tissues, and adequate spatial coverage through translocation to desirable monitoring locations. In this study, we used laboratory incubations to compare three different species of macroalgae as bioindicators, and a field experiment to investigate the applicability of the technique for the large-scale mapping of nutrient plumes. Cladophora valonioides was selected for the field experiment as it showed rapid changes in δ(15)N values in the laboratory incubations, was abundant in shallow depths making collection cost-efficient, and had tough thalli capable of withstanding deployment in open water. Ecklonia radiata also performed well in the laboratory incubations, but field harvest from subtidal depths was comparatively more expensive. Ulva lactuca had fragile thalli, and large nitrogen reserves that acted to mask the isotopic signal of newly acquired nitrogen. Cladophora valonioides was translocated to 246 sites covering an area of ~445 km(2) along the highly urbanized temperate coast of Adelaide, South Australia. The resulting isotopic signatures of nitrogen in tissues were spatially interpolated to produce maps of land-derived nutrient plumes, to model probability and standard error in the predictive surface, and to optimize sampling design. 相似文献
25.
Robert B. Snyder W. Ira Wilson Irving Johnson Albert A. Jonke 《Journal of the Air & Waste Management Association (1995)》2013,63(10):975-981
The information presented in this paper is directed to engineers who are involved with environmental emissions from coal conversion plants. Synthetic sorbents were investigated as an alternative to natural sorbents (limestone) for the removal of SO2 from the combustion gas in a fluidized-bed coal combustor. The sulfation rate of a synthetic sorbent, CaO in α-AI2O3, was determined as a function of gas composition, temperature, and calcium concentration in the sorbent. The reaction was found to be diffusion-controlled above 850°C and kinetically controlled at lower temperatures. The physical characteristics of the support material have a major effect oh the sulfation kinetics. Porosity measurements indicated that supports containing large pores (>0.2 µm) produced sorbents having high sulfation rates and that pores with diameters less than 0.2 µm did not contribute significantly to the capture of SO2. The sorbents SrO in α-AI2O3 and BaO in α-AI2O3 had lower SO2 capture rates than did CaO in α-AI2O3. The alkali metal oxide sorbents K2O and Na2O in α-AI2O3 captured SO2 much faster than did the alkaline earth metal oxides. 相似文献
26.
We tested the hypothesis that the influence of early work experiences on organization commitment would be moderated by the value employees place on these experiences. We measured work values in two samples of recent university graduates prior to organizational entry, and obtained measures of commensurate work experiences and three forms of commitment (affective, continuance, and normative: Allen and Meyer, 1990) on different occasions following entry. Regression analyses revealed that values and experiences did interact in the prediction of affective commitment and normative commitment, but that the nature of the interaction was different for different work value/experience combinations. The findings provide some challenge to the common sense assumption that positive work experiences will have the strongest effect on commitment among those who most value such experiences. Implications for research and practice are discussed. © 1998 John Wiley & Sons, Ltd. 相似文献
27.
Irving Schiffman 《Environmental Impact Assessment Review》1985,5(2):183-193
Despite obstacles inherent in the structure of government and the lack of a strong national constituency, environmental impact assessment became a policy-making element in the government of Israel in 1982. The Environmental Protection Service formed in 1973 now needs to develop strategies to promote environmental awareness and environmentally informed decision making among the public, private and public developers, and within the Ministry of the Interior. 相似文献
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29.
Andrew D. Irving David Balata Francesco Colosio Guillaume A. Ferrando Laura Airoldi 《Marine Biology》2009,156(6):1223-1231
Recruitment is essential for the maintenance of populations, but far more is typically known about the more easily-observed
adult stages than their smaller, often microscopic early life-history counterparts. This discrepancy can be particularly problematic
for populations of foundation species that create biogenic habitat for a multitude of other taxa, but are themselves prime
candidates for exploitation, fragmentation, and loss, and therefore become the focus of restoration efforts partly or fully
dependent on recruitment. The purpose of this study was to improve ecological understanding for early life-history stages
of the habitat-forming marine alga Cystoseira barbata (Stackhouse) C. Agardh (Fucales: Sargassaceae), member of a genus that has experienced considerable fragmentation and population
decline on European coasts. Using experimental manipulations of water temperature, light intensity, and sediment accumulation,
we observed that sediment virtually precluded recruitment of C. barbata, and greatly impacted the survival of recently settled germlings (up to ~83% mortality). Stronger intensities of light facilitated
the growth of germlings, including the capacity for ~50% of them to outgrow detrimental sediment and survive. Temperature
(10 vs. 16°C) had no effect on early recruitment, survival, or growth. This information helps to identify likely causes and
locations of recruitment failure, and by extension, the conditions needed (either naturally or through human intervention)
to facilitate recruitment and possible habitat restoration. Ultimately, this knowledge can increase our capacity to predict
population persistence and the likely success of restoration efforts. 相似文献
30.