Nutrient limitation of phytoplankton growth in Georgia nearshore waters     

S. Stephen Bishop  Kurt A. Emmanuele  James A. Yoder 《Estuaries and Coasts》1984,7(4):506-512

Nutrient enrichment experiments were conducted to investigate the utilization of dissolved organic and inorganic nitrogen by marine phytoplankton in Georgia coastal waters. Natural populations of marine phytoplankton, enriched with different concentrations of ammonium chloride and other plant nutrients, were grown under controlled temperature and irradiance conditions until the populations reached “stationary phase.” Results showed that (1) phytoplankton are limited by DIN up to ca. 20μM, when another nutrient (phosphate or silicate) becomes limiting, (2) very little naturally-occurring DON is directly utilized for growth, (3) very little DON is indirectly made available for growth over time periods of days to ca. 1 week, and (4) trace metals and vitamins do not significantly limit phytoplankton growth.  相似文献   

Point pattern analysis of eruption points for the Mount Gambier volcanic sub-province: a quantitative geographical approach to the understanding of volcano distribution   总被引：1，自引：0，他引：1  

Mark A Bishop 《Area》2007,39(2):230-241

This paper is an examination of the method of point pattern analysis, its potential and limitations, and a discussion of the patterns of volcano geography for the Mount Gambier volcanic sub-province of southeastern Australia. Two classes of point pattern measure were employed: the centrographic measure of point dispersion and directional bias, and distance-based measures of ordered neighbours. Spatial analysis has shown the distribution and pattern of eruption points to be heterogeneous, anisotropic and not completely spatially random, and offers through the exploration of point dispersion, orientation and pattern, a viewpoint on the geography of a low-volume, basaltic monogenetic volcanic system.  相似文献   

Christianity,the Coptic religion and ethnic minorities in Egypt     

Bishop Gregorius 《GeoJournal》1982,6(1):57-62

The Copts are the direct descendants of the Old Egyptians. Today they form the Christian minority in Egypt whose number is about nine millions. The Coptic language originates from the language spoken in Ancient Egypt and the Coptic music has also its roots in the Old Egyptian music. Both the Coptic language and Coptic music have survived in the liturgy of the Coptic Church till today. The early Coptic Church had a great impact on the Christian world. Apostle Athanasius of Alexandria formulated the Christian Creed, St. Antonius the Great and St. Pakhomius founded the monastic system, and the Theological School of Alexandria had a great reputation. The Coptic Church is also the church of the martyrs and it lived through long ages of severe persecution. Yet the Copts are wellknown for loyalty to their country and they are proud of their Egyptian identity.  相似文献   

Temporal and spatial variations in the spawning activity of the micronektonic shrimp,Sergia lucens (hansen) in Suruga Bay,Japan     

Gretchen H. Bishop  Makoto Omori  Fumio Muranaka 《Journal of Oceanography》1989,45(4):243-250

Temporal and spatial variations in the spawning activity ofSergia lucens were investigated in relation to some environmental conditions of Suruga Bay. The daily egg abundance varied considerably with the coefficient of variation from 81% to 269% in July. The spawning activity was most clearly affected by temperature, but the relationship to lunar period and content of chlorophylla were not obvious. Timing of the July spawning is predictable with increase of the surface temperature to 24°C and strong vertical movements of the 18°C isotherm depth; it is also related to modal length of the shrimp in June. It is suggested that intrusion of cold water at 20–50 m affects reproduction of the shrimps and vertical distribution of eggs and larvae. The shrimp population seemed to relate principally to two spawning grounds,i.e. the head part and the western part of the bay. The timing of spawning is not always synchronous throughout the bay. The spawning is sporadic and the distribution of eggs is patchy. This may reflect a recent decrease in the population of the shrimp due to increased fishing pressure.A part of the present paper is based on the thesis submitted by G. H. B. in partial fulfilment of the requirements for her degree of Master of Science at the Tokyo University of Fisheries in 1986.  相似文献   

Reflectance spectroscopy of ferric sulfate-bearing montmorillonites as Mars soil analog materials     

Bishop JL  Pieters CM  Burns RG  Edwards JO  Mancinelli RL  Fröschl H 《Icarus》1995,117(1):101-119

Spectroscopic analyses have shown that smectites enhanced in the laboratory with additional ferric species exhibit important similarities to those of the soils on Mars. Ferrihydrite in these chemically treated smectites has features in the visible to near-infrared region that resemble the energies and band strengths of features in reflectance spectra observed for several bright regions on Mars. New samples have been prepared with sulfate as well, because S was found by Viking to be a major component in the surface material on Mars. A suite of ferrihydrite-bearing and ferric sulfate-bearing montmorillonites, prepared with variable Fe3+ and S concentrations and variable pH conditions, has been analyzed using reflectance spectroscopy in the visible and infrared regions, M?ssbauer spectroscopy at room temperature and 4 K, differential thermal analysis, and X-ray diffraction. These analyses support the formation of ferrihydrite of variable crystallinity in the ferrihydrite-bearing montmorillonites and a combination of schwertmannite and ferrihydrite in the ferric sulfate-bearing montmorillonites. Small quantities of poorly crystalline or nanophase forms of other ferric materials may also be present in these samples. The chemical formation conditions of the ferrihydrite-bearing and ferric sulfate-bearing montmorillonites influence the character of the low temperature M?ssbauer sextets and the visible reflectance spectra. An absorption minimum is observed at 0.88-0.89 micrometers in spectra of the ferric sulfate-bearing samples, and at 0.89-0.92 micrometers in spectra of the ferrihydrate-bearing montmorillonites. M?ssbauer spectra of the ferric sulfate-bearing montmorillonites indicate variable concentrations of ferrihydrite and schwertmannite in the interlaminar spaces and along grain surfaces. Dehydration under reduced atmospheric pressure conditions induces a greater effect on the adsorbed and interlayer water in ferrihydrite-bearing montmorillonite than on the water in ferric sulfate-bearing montmorillonite. Reflectance spectra of ferric sulfate-bearing montmorillonite include a strong 3-micrometers band that is more resistant to dry atmospheric conditions than the 3-micrometers band in spectra of similarly prepared ferrihydrite-bearing montmorillonites.  相似文献   

A note on surface wind-driven flow     

Joseph M. Bishop 《Ocean Engineering》1979,6(3):273-284

A simple operationally oriented model of surface wind-driven currents is presented in which Lagrangian surface drift is assumed to be composed of a linear combination of a wave-induced Stokes drift plus a wind-driven Ekman drift. Using this approach, Stokes drift accounts for as much as half the total surface current magnitude. The Lagrangian current is predicted to be about 3.5% of the 10 m wind magnitude directed in the sense of an Ekman spiral about a 20° deviation angle. For comparison to this model, a second model is proposed that accounts for the interaction of Stokes current and Coriolis force. An inference drawn from this model is that there is only weak coupling between Coriolis force and Stokes drift. Such a conclusion, if correct, leads one to focus attention on the Lagrangian model for operationally oriented current estimates. Results of the Lagrangian model agree with observations of investigators for currents at the air-sea interface and may have application in the movement f oil slicks or surface drifters at sea under fetch or duration limited sea states.  相似文献   

How effective are plant macrofossils as a proxy for macrophyte presence? The case of <Emphasis Type="Italic">Najas flexilis</Emphasis> in Scotland     

Isabel J. Bishop  Helen Bennion  Ian R. Patmore  Carl D. Sayer 《Journal of Paleolimnology》2018,60(2):153-165

Preventing biodiversity loss is a key aim of modern conservation, and paleolimnology can inform conservation strategies for target species and habitats where other data are unavailable. Care must be taken to fully understand the possibilities and limits of such techniques, particularly where they concern single species. This study uses plant and seed distribution data to inform macrofossil reconstructions of the rare macrophyte Najas flexilis (Slender Naiad) in Scotland, UK. It answers three questions: (a) How does the location of N. flexilis seeds in the surface sediments relate to the distribution of N. flexilis plants? (b) How do the numbers of seeds in surface sediments correlate with % cover of N. flexilis plants across lakes with differing N. flexilis abundances? (c) What are the implications of these findings for paleolimnology? Percentage N. flexilis cover and number of N. flexilis seeds in surface sediments were recorded at ~100 sample points at each of three sites; one where the species was abundant, one where it was occasional and one where it was extinct. At all sites, N. flexilis seeds were present in surface sediments across the entire lake. No correlation between % cover N. flexilis and the number of seeds in surface sediments was found within individual sites. The distribution of seeds in these lakes appeared to be related to multiple environmental and ecological variables including latitude and longitude (proxies for water currents). This is attributed to the ability of seed-bearing N. flexilis plants to fragment and float large distances on water. Between sites, there was a significant difference in the mean seed counts, with higher mean seed counts corresponding to higher abundances of N. flexilis plants. It is concluded that N. flexilis is likely to be well represented in sediment cores taken from any location within a basin, but that care should be taken when inferring changes in N. flexilis abundance from changes in the numbers of seeds in sediment samples. This work demonstrates that the reproductive ecology (number of seeds produced and dispersal mechanisms) is an important factor to consider when attempting reconstructions of single aquatic plant populations from macrofossil records.  相似文献   

Water transit times and flow paths from two line injections of 3H and 36Cl in a microcatchment at Gårdsjön,Sweden     

Lars Nyberg  Allan Rodhe  Kevin Bishop 《水文研究》1999,13(11):1557-1575

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Shoreline erosion: a cautionary note in using small farm dams to determine catchment erosion rates     

Sara D. Lloyd  Paul Bishop  Ivars Reinfelds 《地球表面变化过程与地形》1998,23(10):905-912

Data from 10 small farm dams in SE Australia show that shoreline erosion due to farm livestock access to the dams can account for a significant proportion (up to 85%) of sediment contained in the dam. The volumes of sediment resulting from such shoreline erosion may be of the same order as the volumes produced by gully erosion in the dams' catchments, prompting caution in using farm dams to which livestock have access to determine small catchment erosion rates. Other issues, related to the trap efficiency, also mean that erosion estimates based on farm dam sedimentation should be treated with caution. © 1998 John Wiley & Sons, Ltd.  相似文献   

Seasonal and runoff-related changes in total organic carbon concentrations in the River Öre, Northern Sweden     

Anneli Ågren  Mats Jansson  Hans Ivarsson  Kevin Bishop  Jan Seibert 《Aquatic Sciences - Research Across Boundaries》2008,70(1):21-29

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