Trace metal fluxes to nearshore Long Island Sound sediments     

WM.Berry Lyons  WM.F Fitzgerald 《Marine pollution bulletin》1980,11(6):157-161

Sediments are very important as trace metal ‘sinks’ in coastal areas. In this paper we present data on the concentrations and calculated fluxes of the trace metals, Fe, Mn, Cu, Pb, Zn, Cd and Ag at nearshore sites in Long Island Sound. In both areas a percentage of the metal accumulation can be ascribed to local human activities with the highest anthropogenic metal fluxes occurring closest to their source.  相似文献   

Geomicrobiology of Blood Falls: An Iron-Rich Saline Discharge at the Terminus of the Taylor Glacier, Antarctica   总被引：1，自引：0，他引：1  

Jill A. Mikucki  Christine M. Foreman  Birgit Sattler  W. Berry Lyons  John C. Priscu 《Aquatic Geochemistry》2004,10(3-4):199-220

Blood Falls, a saline subglacial discharge from the Taylor Glacier, Antarctica provides an example of the diverse physical and chemical niches available for life in the polar desert of the McMurdo Dry Valleys. Geochemical analysis of Blood Falls outflow resembles concentrated seawater remnant from the Pliocene intrusion of marine waters combined with products of weathering. The result is an iron-rich, salty seep at the terminus of Taylor Glacier, which is subject to episodic releases into permanently ice-covered Lake Bonney. Blood Falls influences thegeochemistry of Lake Bonney, and provides organic carbon and viable microbes to the lakesystem. Here we present the first data on the geobiology of Blood Falls and relate it totheevolutionary history of this unique environment. The novel geological evolution of thissubglacial environment makes Blood Falls an important site for the study of metabolic strategiesin subglacial environments and the impact of subglacial efflux on associated lake ecosystems.  相似文献   

Halogen geochemistry of the McMurdo dry valleys lakes, Antarctica: Clues to the origin of solutes and lake evolution   总被引：1，自引：0，他引：1  

W. Berry Lyons  Kathleen A. Welch  John Olesik  Giles M. Marion 《Geochimica et cosmochimica acta》2005,69(2):305-323

We have determined the halogen and boron concentrations in the ice-covered lakes of Taylor Valley, Antarctica, to better establish the sources of salts and evolutionary histories of these unusual water bodies. In addition, we report on a series of ¹²⁹I measurements that were compared with previous ³⁶Cl data that also help constrain the source of solutes and histories of the lakes. The new data, when put into context of previous work on these systems over the past forty years, allow us to make the following conclusions. The primary source of solutes to Lake Hoare, the youngest of the lakes, is the dissolution of marine aerosols and aeolian salts and the chemical weathering of dust on the glaciers. The geochemistry of Lake Fryxell, the brackish water lake, is primarily dominated by the diffusion from a halite-saturated brine at the sediment-water interface and the recent infilling of the lake by glacier meltwater. These waters have chemical weathering and marine aerosols components. Lake Bonney has two distinct lobes whose hypersaline hypolimnia have different chemistries. Both of the lobes are remnants of ancient marine waters that have been modified by the input of weathering products. This lake has also been modified by periods of cryogenic concentration when solutes have been lost via mineral precipitation. Thus the geochemistry of Lake Bonney owes its unusual geochemistry, in part, to variations in the climate in the Taylor Valley over at least the past 300kyr. The ¹²⁹I data from the Taylor Valley are similar to those from fracture fluids in crystalline rocks from the Northern Hemisphere.  相似文献   

Vegetation analysis of a typical mangrove swamp—Lai Chi Wo coast of Hong Kong     

Lu Chang-yi  Wong Yuk-shan  F. Y. Tam Nora  Berry Richard 《中国海洋湖沼学报》1998,16(1):72-77

A vegetation analysis reveals that the Lai Chi Wo mangrove swamp in Hong Kong has 10 mangrove species comprising 76.9% of the total number of mangrove species in Hong Kong. This swamp is a mixed community dominated byAegiceras corniculatum, Heritiera littoralis, Excoecaria agallocha, Kandelia candel, Bruguiera gymnorrhiza, with importance values of 37.88, 28.19, 14.33, 11.33 and 8.27 respectively. The community’s mangrove species diversity and evenness, as based on the Shannon-Wiener Function, were 1.44 and 62.01%, which were lower than those of the south su-tropical evergreen broad-leaf forest community but its ecological dominance (0.26) was higher. The correlation information field (CIF) method, a useful analytical method for complex forest community, was adopted in the present mangrove analysis. The species correlation information was:Aegiceras corniculatum (0.268)>Heritiera littoralis (0.250)>Kandelia candel (0.220)>Excoecaria agallocha (0.169)>Bruguiera gymnorrhiza (0.101). The correlation information of the mangrove community was 1.008. This work was financially supported by the Agriculture and Fisheries Department of The Hong Kong Government and The Hong Kong University of Science & Technology.  相似文献   

Paleolimnology of the McMurdo Dry Valleys,Antarctica   总被引：1，自引：0，他引：1  

Peter T. Doran  Robert A. Wharton Jr.  W. Berry Lyons 《Journal of Paleolimnology》1994,10(2):85-114

The McMurdo Dry Valleys presently contain more than 20 permanent lakes and ponds, which vary markedly in character. All, with the exception of a hypersaline pond, have a perennial ice-cover. The dry valley lakes, and lakes in other ice-free regions of continental Antarctica, are unique on this planet in that they consistently maintain a thick year-round ice cover (2.8–6.0 m) over liquid water. The persistent ice covers minimize wind-generated currents and reduce light penetration, as well as restricting sediment deposition into a lake and the exchange of atmospheric gases between the water column and the atmosphere. From a paleolimnological perspective, the dry valley lakes offer an important record of catchment and environmental changes. These lakes are also modern-day equivalents of periglacial lakes that were common during glacial periods at temperature latitudes. The present lakes are mostly remnants of larger glacial lakes that occupied the valleys in the past, perhaps up to 4.6 Ma ago. Two of the valleys contain evidence of being filled with large glacial lakes within the last 10000 years. Repeated drying and filling events since then have left a characteristic impression on the salt profiles of some lakes creating a unique paleo-indicator within the water column. These events are also marked in the sediments by the concentration and dilution of certain chemical constituents, particularly salts, and are also corroborated by carbonate speciation and oxygen isotope analysis. Stratigraphic analysis of dry valley lake sediments is made difficult by the occurrence of an old carbon reservoir creating spurious radiocarbon dates, and by the high degree of spatial variability in lake sedimentation. From a biological perspective, the lakes are relatively simple, containing various taxa of planktonic and benthic microorganisms, but no higher forms of life, which is an advantage to paleolimnologists because there is no bioturbation in the sediments. Useful biological paleo-indicators found in the sediments include cyanobacterial filament sheaths, diatom frustules and other eukaryotic algal cells, protozoan cysts, photosynthetic pigments, and minerals (e.g. carbonates) associated with microbial activity. Future work will benefit from fully characterizing the connection between the ice covers, environmental conditions, and paleo-indicators, thereby allowing refinement of inferences made concerning the paleoenvironment. New dating techniques need to be tested in this environment to overcome the problems associated with radiocarbon dating. The establishment of a detailed and focused paleolimnological campaign is proposed.  相似文献   

Watershed-scale geochemistry     

W. Berry Lyons 《Applied Geochemistry》2007

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Africa and the global carbon cycle     

Christopher A Williams  Niall P Hanan  Jason C Neff  Robert J Scholes  Joseph A Berry  Scott A Denning  David F Baker 《Carbon balance and management》2007,2(1):3-13

The African continent has a large and growing role in the global carbon cycle, with potentially important climate change implications. However, the sparse observation network in and around the African continent means that Africa is one of the weakest links in our understanding of the global carbon cycle. Here, we combine data from regional and global inventories as well as forward and inverse model analyses to appraise what is known about Africa's continental-scale carbon dynamics. With low fossil emissions and productivity that largely compensates respiration, land conversion is Africa's primary net carbon release, much of it through burning of forests. Savanna fire emissions, though large, represent a short-term source that is offset by ensuing regrowth. While current data suggest a near zero decadal-scale carbon balance, interannual climate fluctuations (especially drought) induce sizeable variability in net ecosystem productivity and savanna fire emissions such that Africa is a major source of interannual variability in global atmospheric CO₂. Considering the continent's sizeable carbon stocks, their seemingly high vulnerability to anticipated climate and land use change, as well as growing populations and industrialization, Africa's carbon emissions and their interannual variability are likely to undergo substantial increases through the 21st century.  相似文献   

Three-dimensional evolution of worms and chimneys in the Galactic disc     

Miguel A. de Avillez  David L. Berry 《Monthly notices of the Royal Astronomical Society》2001,328(3):708-718

Three-dimensional modelling of the flow of gas and plasma in a section of the Galaxy has been carried out to study the evolution and formation of Galactic chimneys and worms. It is found that clustered supernovae located on either side of the Galactic plane are sources for the formation of well-collimated chimneys, having widths of ∼     . The thick gas disc may have a role in the collimation of chimneys. Channel maps of disc gas, obtained from the simulations, show the presence of sheet-like structures running perpendicular to the Galactic plane and resembling worms. Worms are believed to result from the break-up of the shells and supershells. However, the simulations show that although some worms correlate well with the debris of broken shells/supershells, others do not. They are cold gas that has been accelerated in the disc and rise on to the thick gas disc.  相似文献   

CHALLENGES OF THE NUMBERS GAME     

Brian J. L. Berry 《The Professional geographer》1981,33(2):161-162

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Oxyanion Concentrations in Eastern Sierra Nevada Rivers – 3. Boron, Molybdenum, Vanadium, and Tungsten     

Kevin H. Johannesson  W. Berry Lyons  Elizabeth Y. Graham  Kathleen A. Welch 《Aquatic Geochemistry》2000,6(1):19-46

Water samples were collected from 10 locations along the Truckee River system, 14 locations along the Walker River system, and 12 locations along the Carson River, and analyzed for B, Mo, V, W, Na, Cl, and pH. Boron concentrations ranged from approximately 2 mol/kg in the upper reaches of the Truckee River to almost 1,200 mol/kg in Pyramid Lake. Molybdenum, V, and W had concentrations in the nanomolal range; Mo varied from a low of about 12 nmol/kg to a high of 3,200 nmol/kg (Walker Lake); V ranged from 9 nmol/kg to approximately 470 nmol/kg; and W varied from a low value around 0.8 nmol/kg (West Walker River) to 1,030 nmol/kg. The high concentrations of these oxyanion-forming trace elements in the rivers reflects (1) the relative stability of these oxyanions (e.g., MoO₄ ^2-, HVO₄ ^2-, WO₄ ^2-, B(OH)₃, and/or B(OH)₄ ^-) in the alkaline, well oxygenated river and lake waters, (2) contributions of hydrothermal waters (especially for B), and (3) weathering of rocks/regolith with high concentrations of these elements. In the case of Mo, V, and W, each exhibited relatively conservative behavior in the upper, oxygenated reaches of all three rivers. During the study period the region experienced a prolonged drought such that the lower reaches of each river were typified by no flow or stagnant waters and probably low oxygen and/or anoxic conditions (although not measured). Reductive processes occurring in the low flow to stagnant reaches of each river could have led to removal of Mo, V, and W from solution as coprecipitates with Fe monosulfides, or via sorption to Fe oxides/oxyhydroxides and/or organic matter. Boron, however, exhibited essentially no or minor removal from these rivers, and instead was added to each river via B-rich hydrothermal waters (e.g., Steamboat Creek from Steamboat Hot Springs), or by B-rich groundwaters via base-flow during the extensive drought.  相似文献