Physiological responses of Mytilus edulis L. to parasitic infestation by Mytilicola intestinalis     

Bayne  B. L.; Gee  J. M.; Davey  J. T.; Scullard  C. 《ICES Journal of Marine Science》1978,38(1):12-17

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Arsenic release from chlorine-promoted alteration of a sulfide cement horizon: Evidence from batch studies on the St. Peter Sandstone,Wisconsin, USA     

Nicole West  Madeline Schreiber  Madeline Gotkowitz 《Applied Geochemistry》2012

Elevated As concentrations have been measured in wells in the St. Peter Sandstone aquifer of eastern Wisconsin, USA. The primary source is As-bearing sulfide minerals (pyrite and marcasite) within the aquifer. There is concern that well disinfection by chlorination may facilitate As release to groundwater by increasing the rate and extent of sulfide oxidation. The objective of this study was to examine the abiotic processes that mobilize As from the aquifer solids during controlled exposure to chlorinated solutions. Thin sections made from sulfidic aquifer material were characterized by quantitative electron probe micro-analysis before and after 24 h exposure to solutions of different Cl₂ concentrations. Batch experiments using crushed aquifer solids were also conducted to examine changes in solution chemistry over 24 h. Results of the combined experiments indicate that Cl₂ addition affects As release and uptake in two ways. First, Cl₂ increases oxidation of sulfide minerals, releasing more As from the mineral structure. Chlorine addition also increases the rate of Fe(II) oxidation and subsequent hydrous ferric oxide (HFO) precipitation, allowing for increased uptake of As onto the mineral surface. Although HFOs can act as sinks for As, they can release As if biogeochemical conditions (e.g. redox, pH) change. These results have implications not only for disinfection of drinking water wells in the study area, but also suggest that introduction of oxidants may adversely affect water quality during aquifer storage and recovery programs in aquifers containing As-bearing minerals.  相似文献   

Release of arsenic and other trace elements from poultry litter: Insights from a field experiment on the Delmarva Peninsula,Delaware     

Oluyinka Oyewumi  Madeline E. Schreiber 《Applied Geochemistry》2012

A poultry litter application was conducted to examine field scale release and transport of trace elements from poultry litter into the subsurface. Field monitoring before and after litter application demonstrated increases in major ion, nutrient, and trace element concentrations in soil water after application, but concentrations of trace elements were all below regulatory standards. Using laboratory stepwise extractions of litter, calculated leaching rates of trace elements are fastest for As, followed by Cu and Zn. Comparison of the projected (from laboratory extractions) to actual (measured in the field) trace element concentrations in litter show that laboratory-derived rates generally over-predict leaching, but the long-term projections of Cu and Zn concentrations remaining in litter are within 20% of the field measurement. Arsenic leaching from litter was under-predicted by the laboratory leaching model by over 100%, suggesting that other processes (perhaps biological) occurring in the field allowed for additional As to be leached/removed. Mass balance coupled with conservative tracer calculations reveal that the vadose sediment was the main sink for the trace elements, with lesser uptake of Cu and Zn (not As) by orchard grass. Overall, results of this study showed that the fate and transport of trace elements from poultry litter are controlled by their leaching rate from litter, adsorption, uptake in vegetation and dilution. An additional process affecting As is biotransformation.  相似文献   

Measurement and calculation of OH reactivity at a United Kingdom coastal site     

James D. Lee  Jennifer C. Young  Katie A. Read  Jacqueline F. Hamilton  James R. Hopkins  Alastair C. Lewis  Brian J. Bandy  James Davey  Peter Edwards  Trevor Ingham  Daniel E. Self  Shona C. Smith  Michael J. Pilling  Dwayne E. Heard 《Journal of Atmospheric Chemistry》2009,64(1):53-76

Measurements of OH reactivity were made at the Weybourne Atmospheric Observatory on the North Norfolk coast, UK in May 2004. A wide range of supporting species was also measured concurrently as part of the TORCH-2 field campaign, allowing a detailed study of the OH oxidation chemistry to be carried out. Measurements were made in a variety of air masses, with the 3 most prevalent being air from the Atlantic that arrived at the site from over mainland UK in a South Westerly direction, and much cleaner Northerly air that originated over the far North Sea or Arctic, passed over the North Sea and arrived at the site from a North/North Easterly direction. Direct OH reactivity measurements were made on 6 days during the campaign and with influence of 2 of the 3 air masses prevalent during the study period. The average, minimum and maximum measured OH reactivity are: 4.9, 1.3 and 9.7 respectively. The measured OH reactivity was compared to key OH sinks such as NO₂ and CO and a general positive correlation was observed. OH reactivity (k′) was then calculated using the full range of OH sinks species that were measured (including >30 NMHCs) and their pseudo first order rate constants for reaction with OH. For much of the measurement period there is a significant difference between the measured and calculated k′, with an average value of k′_meas- k′_calc?=?1.9 s^-1, indicative of unmeasured OH sinks. A zero-dimensional box model containing a subset of the Master Chemical Mechanism was used to calculate the OH reactivity more accurately. The simultaneously measured trace species were used as inputs to the model and their oxidative degradation was described by a chemical mechanism containing ~5,000 species. The extra OH sinks species produced by the model, resulted in an improvement in the agreement between k′_meas and k′_calc, however the averaged missing OH reactivity across the entire measurement period remained at 1.4 s^-1. Speculation is made as to the source of this missing reactivity, including reference to studies showing that a potentially large number of high molecular weight aromatic species could be unmeasured by standard instrumentation.  相似文献   

Species diversity and distribution for phytoplankton of the Pearl River estuary during rainy and dry seasons   总被引：11，自引：0，他引：11  

Huang L  Jian W  Song X  Huang X  Liu S  Qian P  Yin K  Wu M 《Marine pollution bulletin》2004,49(7-8):588-596

Based on data collected at 31 stations and 1 continuous station in the Pearl River estuary during cruises of July 1999 (rainy season) and January 2001 (dry season), this study examined taxonomic composition, abundance, and spatial distribution of phytoplankton. Results indicated 130 species of phytoplankton in the samples from the rainy season, and 132 species in the dry season. Among them, in the rainy season, 82 species of diatom, 39 fresh-water and half-fresh-water species and 41 species of red tide organisms were found. Within these, there were 54 tropical and sub-tropical species, 47 cosmopolitan species and 17 temperate species. The abundance of phytoplankton in the rainy season was higher than that of the dry season, with an average of 6.3 x 10(5) cells x L(-1) and 1.4 x 10(5) cells x L(-1), respectively. Diversity index (H') and evenness (J) were 2.47 and 0.57 in the rainy season, and 2.01 and 0.54 in the dry season. The dominant phytoplankton species in the rainy season was Skeletonema costatum with an average of 2.8 x 10(5) cells x L(-1) and 45.0% of the total phytoplankton abundance. In the dry season, Eucampia zoodiacus became the key dominant species (5.9 x 10(4) cells x L(-1)) when it was 43.47% of the total phytoplankton abundance. Distribution of the dominant species varied with salinity of sea-water, and their amounts correlated negatively with nutrients and zooplankton.  相似文献   

EFFECTS OF CO-CULTURE AND SALINITY ON THE GROWTH AND AGAR YIELD OF GRACILARIA TENUISTIPITATA VAR LIUI ZHANG ET XIA     

贺丽虹  吴汪黔生  钱培元  朱明远 《中国海洋湖沼学报》2002,(4)

ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｒｅｃｅｎｔｙｅａｒｓ,ｃｏ ｃｕｌｔｕｒｅ (ｉｎｔｅｇｒａｔｅｄｃｕｌｔｕｒｅ )ｏｆｍａｒｉｎｅｓｐｅｃｉｅｓ (ａｌｇａｅａｎｄａｎｉｍａｌｓ)ｈａｓｒｅｃｅｉｖｅｄｇｒｅａｔａｔｔｅｎｔｉｏｎ .Ｉｎｃｏ ｃｕｌｔｕｒｅｓｙｓｔｅｍｔｈｅａｌｇａｅａｃｔｉｖｅｌｙｕｐｔａｋｅＣＯ2 ａｎｄｔｈｅｍｅｔａｂｏｌｉｃｗａｓｔｅｓ(ｓｕｃｈａｓＮＨ4 +,ＮＯ2 - ,ＮＯ3- ｅｔｃ)ａｓｎｕｔｒｉｅｎｔｓｏｕｒｃｅｓ,ａｎｄｒｅｌｅａｓｅＯ2 ｔｏｔｈｅｓｕｒｒｏｕｎｄｉｎｇｅｎｖｉｒｏｎ …  相似文献   

Dating the introduction of cereal cultivation to the British Isles: early palaeoecological evidence from the Isle of Man     

James B. Innes  Jeffrey J. Blackford  Peter J. Davey 《第四纪科学杂志》2003,18(7):603-613

The adoption of cereal cultivation is a key benchmark in the transition from Mesolithic hunter–gatherer foraging to Neolithic farming economies, but the nature, timing and ecological–cultural context of the earliest cereal use in the British Isles and northwest Europe is still uncertain. We present AMS radiocarbon dating and fine‐resolution pollen evidence from the Isle of Man for cereal growing in the latter stages of a distinct episode of forest disturbance at almost 6000 yr BP (uncalibrated). The coherent ecological structure of this phase at the fine resolution level suggests that it records cereal cultivation well before the Ulmus decline, rather than wild grass pollen grains. This example is one of a cluster of early dates for cereal‐type pollen near the start of the sixth millenium BP, including several around the Irish Sea, which indicate that the introduction of cereal agriculture probably occurred as early in the central British Isles as in the northern European plain. This early cereal phase is followed later by a probable phase of pre‐Ulmus decline pastoral activity. We also report Mesolithic age woodland disturbance around 7000 yr BP (uncalibrated) and the first radiocarbon dates for mid‐Holocene forest history of the Isle of Man. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

STOIC: a study of coupled model climatology and variability in tropical ocean regions   总被引：13，自引：4，他引：13  

M. Davey  M. Huddleston  K. Sperber  P. Braconnot  F. Bryan  D. Chen  R. Colman  C. Cooper  U. Cubasch  P. Delecluse  D. DeWitt  L. Fairhead  G. Flato  C. Gordon  T. Hogan  M. Ji  M. Kimoto  A. Kitoh  T. Knutson  M. Latif  H. Le Treut  T. Li  S. Manabe  C. Mechoso  G. Meehl  S. Power  E. Roeckner  L. Terray  A. Vintzileos  R. Voss  B. Wang  W. Washington  I. Yoshikawa  J. Yu  S. Yukimoto  S. Zebiak 《Climate Dynamics》2002,18(5):403-420

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Survey of metals in sediments near Quonset Point,Rhode Island     

R. Eisler  R.L. Lapan  G. Telek  E.W. Davey  A.E. Soper  M. Barry 《Marine pollution bulletin》1977,8(11):260-264

Elevated levels of silver, cadmium, cobalt, chromium, copper, iron, manganese, nickel, lead and zinc were observed in sediments collected from Narragansett Bay off Quonset Point during autumn of 1973. The probable source of the metals contamination was an electroplating facility on Quonset Point, in continuous operation from 1943 until it was closed in spring of 1973. Data on elemental composition of surficial sediments collected from various geographical locations reported by other investigators are presented and compared to those reported herein.  相似文献   

Joint hypocentre determination of intermediate depth earthquakes in Fiordland, New Zealand     

Euan G.C. Smith  F.J. Davey 《Tectonophysics》1984,104(1-2)

Relocation of well observed, intermediate depth earthquakes in the Fiordland region by the method of joint hypocentre determination has revealed some fine structure in the Benioff zone. The earthquakes occur in three groups. The central group is the largest and occupies a planar volume less than 15 km thick striking N40°E and dipping at 80°. The deepest events in the region, at depths of 150 km, occur at the northeast end of this group. The two smaller groups lie to the northeast and to the south of the main group. The focal mechanism of the majority of the main group is that of thrust faulting. We suggest that the main group lies within a section of Indian plate lithosphere which has been broken off and rotated into its observed position and that the northern edge of the unbroken subducted Indian plate is indicated by the southern group. We suggest that the small northeastern group has quite a different tectonic origin and is similar to a group of earthquakes further north which are at a similar distance from, and presumably related to, the Alpine Fault.Use has also been made of the travel-time information which is a by-product of the joint hypocentre method to construct upper mantle velocity models for P and S waves in the South Island. The features of this model are a high-velocity region in the vicinity of the Benioff zone, and a subcrustal zone of high seismic velocities running east-west across the center of the South Island in an otherwise normal mantle.  相似文献