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11.
Greg?K?Druschel Martin?AA?SchoonenEmail author D?Kirk?Nordstrom James?W?Ball Yong?Xu Corey?A?Cohn 《Geochemical transactions》2003,4(1):12
A sampling protocol for the retention, extraction, and analysis of sulfoxyanions in hydrothermal waters has been developed
in the laboratory and tested at Yellowstone National Park and Green Lake, NY. Initial laboratory testing of the anion-exchange
resin Bio-Rad™ AG1-X8 indicated that the resin was well suited for the sampling, preservation, and extraction of sulfate and
thiosulfate. Synthetic solutions containing sulfate and thiosulfate were passed through AG1-X8 resin columns and eluted with
1 and 3 M KCl, respectively. Recovery ranged from 89 to 100%. Comparison of results for water samples collected from five
pools in Yellowstone National Park between on-site IC analysis (U.S. Geological Survey mobile lab) and IC analysis of resin-stored
sample at SUNY-Stony Brook indicates 96 to 100% agreement for three pools (Cinder, Cistern, and an unnamed pool near Cistern)
and 76 and 63% agreement for two pools (Sulfur Dust and Frying Pan). Attempts to extract polythionates from the AG1-X8 resin
were made using HCl solutions, but were unsuccessful. Bio-Rad™ AG2-X8, an anion-exchange resin with weaker binding sites than
the AG1-X8 resin, is better suited for polythionate extraction. Sulfate and thiosulfate extraction with this resin has been
accomplished with KCl solutions of 0.1 and 0.5 M, respectively. Trithionate and tetrathionate can be extracted with 4 M KCl.
Higher polythionates can be extracted with 9 M hydrochloric acid. Polythionate concentrations can then be determined directly
using ion chromatographic methods, and laboratory results indicate recovery of up to 90% for synthetic polythionate solutions
using AG2-X8 resin columns. 相似文献
12.
Inorganic nitrogen dynamics in intertidal rocky biofilms and sediments of the Douro River estuary (Portugal) 总被引：1，自引：0，他引：1
Catarina M. Magalhäes William J. Wiebe Samantha B. Joye Adriano A. Bordalo 《Estuaries and Coasts》2005,28(4):592-607
In this study rates of oxygen, ammonium (NH4
+), nitrate (NO3
−), nitrite (NO2
−), and nitrous oxide (N2O) fluxes, nitrogen (N) fixation, nitrification, and denitrification were compared between two intertidal sites for which
there is an abundant global literature, muddy and sandy sediments, and two sites representing the rocky intertidal zone where
biogeochemical processes have scarcely been investigated. In almost all sites oxygen production rates greatly exceeded oxygen
consumption rates. During daylight, NH4
+ and NO3
− uptake rates together with ammonification could supply the different N requirements of the primary producer communities at
all four sites; N assimilation by benthic or epilithic primary producers was the major process of dissolved inorganic nitrogen
(DIN) removal; N fixation, nitrification, and denitrification were minor processes in the overall light DIN cycle. At night,
distinct DIN cycling processes took place in the four environments, denitrification rates ranged from 9 ± 2 to 360 ± 30 μmol
N2 m−2 h−1, accounting for 10–48% of the water column NO3
− uptake; nitrification rates varied from 0 to 1712 ± 666 μmol NH4
+ m−2 h−1. A conceptual model of N cycle dynamics showed major differences between intertidal sediment and rocky sites in terms of
the mean rates of DIN net fluxes and the processes involved, with rocky biofilm showing generally higher fluxes. Of particular
significance, the intertidal rocky biofilms released 10 times the amount of N2O produced in intertidal sediments (up to 17 ± 6 μmol N2O m−2 h−1), representing the highest N2O release rates ever recorded for marine systems. The biogeochemical contributions of intertidal rocky substrata to estuarine
and coastal processes warrant future detailed investigation. 相似文献
13.
Several flatfishes spawn in oceanic waters and pelagic larvae are transported inshore to settle in the nursery areas, usually estuaries, where they remain during their juvenile life. Nursery areas appear as extremely important habitats, not only for juveniles but also for the earlier planktonic larval fish. Yet, the majority of nursery studies tend to focus only on one development stage, missing an integrative approach of the entire early life that fishes spent within a nursery ground. Thus, the present study assessed the influence of environmental parameters on the dynamics of the larval and juvenile flatfishes, throughout their nursery life in the Lima Estuary. Between April 2002 and April 2004, fortnightly subsurface ichthyoplankton samples were collected and juveniles were collected from October 2003 until September 2005. Larval assemblages comprised nine flatfish species, while only six were observed among the juvenile assemblages. Solea senegalensis and Platichthys flesus were the most abundant species of both fractions of the Lima Estuary flatfishes. Larval flatfish assemblages varied seasonally, without relevant differences between lower and middle estuary. Platichthys flesus dominated the spring samples and summer and autumn periods were characterized by an increase of overall abundance and diversity of larval flatfishes, mainly S. senegalensis, associated with temperature increase and reduced river flow. On the contrary, during the winter abundance sharply decreased, as a consequence of higher river run-off that might compromised the immigration of incompetent marine larvae. Juvenile flatfishes were more abundant in the middle and upper areas of the estuary, but the species richness was higher near the river mouth. Sediment type, distance from the river mouth, salinity, temperature and dissolved oxygen were identified as the main environmental factors structuring the juvenile flatfish assemblages. Juveniles were spatially discrete, with the most abundant species S. senegalensis and P. flesus associated with the middle and upper estuary, while the remaining species were associated with the lower estuarine areas. The larval fraction exhibited distinct dynamics from the juvenile estuarine flatfish community. Larval flatfishes showed a strong seasonal structure mainly regulated by biological features as the spawning season and also by seasonal variations of water characteristics. On the other hand, juvenile flatfishes were markedly controlled by site specific characteristics such as sediments structure, distance from the river mouth and salinity regime. The present study emphasized the idea that the environmental control varies throughout the ontogenetic development, stressing the importance of integrating all the early life of a species in flatfish nursery studies. 相似文献
14.
Study of the influence of different organic pollutants on Cu accumulation by Halimione portulacoides
C. Marisa R. Almeida A. Claúdia Dias Ana P. Mucha A.A. Bordalo M. Teresa S.D. Vasconcelos 《Estuarine, Coastal and Shelf Science》2009
The influence of each of four organic pollutants selected from among those commonly found in coastal areas, 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (DDE), monobutyltin (MBT), Triton X-100 and polycyclic aromatic hydrocarbons (PAHs), on Cu accumulation by Halimione portulacoides was investigated. Experiments were carried out in a laboratory setting, either in hydroponics (sediment elutriate) or in a salt marsh sediment (Cávado River, NW Portugal) soaked in elutriate. Groups of H. portulacoides were exposed to media for 6 days spiked with 10 mg/L Cu(II) and with one of the selected pollutants, at an environmentally realistic concentration. DDE and MBT did not cause any major change on Cu accumulation by H. portulacoides, whereas PAHs slightly increased accumulation only in hydroponics i.e. in the absence of sediment. On the other hand, the non-ionic surfactant Triton X-100 markedly favoured Cu accumulation on plant roots both in the presence and absence of sediment. The addition of DDE, MBT and Triton X-100 also favoured Cu solubility from sediments. Therefore, the simultaneous presence of pollutants from different nature (inorganic and organic) in the estuarine environment may result in a composition of water column, pore water, sediment or biota different of that expected considering the effect of each individual pollutant. 相似文献
15.
Almeida CM Mucha AP Delgado MF Caçador MI Bordalo AA Vasconcelos MT 《Marine environmental research》2008,66(3):311-318
The presence of polycyclic aromatic hydrocarbons (PAHs) may change the mechanisms of metal uptake, thus influencing kinetics and extent of metal phytoextraction. Studies on the subject are scarce, particularly for salt marsh plants. The aim of this work was to investigate the effect of PAHs on the uptake of Cu by Halimione portulacoides, a plant commonly found in salt marshes. Experiments were carried out in the laboratory, either in hydroponics (sediment elutriate) or in sediment soaked in elutriate, which were prepared with sediment and water from a salt marsh of the Cavado river estuary (NW Portugal). Groups of H. portulacoides (grown in a greenhouse) were exposed to those media during six days. Cu(2+) (as Cu(NO(3))(2)), 10(2) and 10(4)mugl(-1), was added to the media as well as 1.6mugl(-1) of the sixteen EPA priority PAHs (0.1mugl(-1) of each PAHs). Cu was assayed in solutions, sediments and different plant tissues before and after experiments. After exposure, photosynthetic efficiency and levels of chlorophylls were also measured, indicating that plant stress indicators were identical in all plants independently of the media to which the plants were exposed. PAHs influenced both the soluble Cu fraction and Cu uptake by plants. The amounts of metal accumulated in both roots and stems were significantly higher when the 10(4)mugl(-1) of Cu enriched elutriate was amended with PAHs. Thus, results suggest that PAHs may modify Cu solubility, the Cu sorption by plants and/or the passive penetration of Cu into the root cells. Therefore, the combined effects of different types of pollutants should be taken in consideration when studying the remediation potential of plants, namely in terms of phytoextraction. 相似文献
16.
Jun Hao Curtis Cleveland Eelin Lim Daniel R Strongin Martin AA Schoonen 《Geochemical transactions》2006,7(1):8-9
The chemolithoautotrophic bacterium, Acidithiobacillus ferrooxidans, commonly occurs in acid mine drainage (AMD) environments where it is responsible for catalyzing the oxidation of pyrite
and concomitant development of acidic conditions. This investigation reports on the growth of this bacterial species on the
pyrite surface and in the aqueous phase at a pH close to 2 as well as the role of adsorbed lipid in preventing pyrite dissolution.
Both acid washed pyrite and acid-washed pyrite coated with lipids were used as substrates in the studies. The choice of lipid,
1,2-bis(10,12-tricosadiynoyl)-sn-Glycero-3-Phosphocholine lipid (23:2 Diyne PC), a phosphocholine lipid, was based on earlier work that showed that this lipid
inhibits the abiotic oxidation rate of pyrite. Atomic force microscopy showed that under the experimental conditions used
in this study, the lipid formed ~4–20 nm layers on the mineral surface. Surface-bound lipid greatly suppresses the oxidation
process catalyzed by A. ferrooxidans. This suppression continued for the duration of the experiments (25 days maximum). Analysis of the bacterial population on
the pyrite surface and in solution over the course of the experiments suggested that the pyrite oxidation was dependent in
large part on the fraction of bacteria bound to the pyrite surface. 相似文献
17.
Pyrite surface interaction with selected organic aqueous species under anoxic conditions 总被引：1，自引：0，他引：1
The interaction between low-molecular weight organic compounds and pyrite under anoxic conditions has been studied using a combination of electrophoresis and batch sorption experiments. The results suggest that acetate, carbamide, ethylamine, formamide, purine, D-ribose, and adenine, as well as the amino acids alanine, cysteine and glycine, interact within the electrophoretic shearplane of the pyrite surface. The observed surface interaction between the negatively charged surface of pyrite and the organic aqueous species takes place regardless of the formal charge of the aqueous species of interest. This indicates that the interaction of organic molecules with pyrite surfaces under anoxic conditions is dictated by interactions with specific surface sites (thiol or iron surface sites) rather than electrostatic forces. Dissolved metals typically enhance the interaction of the organics species. This enhancement is either due to an alteration in the distribution of thiol and iron groups on the pyrite surface or by the formation of ternary surface complexes. 相似文献
18.
Recruitment of flatfish species to an estuarine nursery habitat (Lima estuary, NW Iberian Peninsula)
One of the present concerns of fish biologists involves defining and identifying nursery habitats in the context of conservation and resource management strategies. Fish nursery studies usually report upon nursery occupation during the latter juvenile stages, despite the fact that recruitment to nurseries can start early in life, during the larval phase. Here we investigated the use of a temperate estuarine nursery area, the Lima estuary (NW Portugal), by initial development stages of flatfish species before and after metamorphosis, integrating the larval and juvenile phases. The Lima estuarine flatfish community comprised twelve taxa, seven of which were present as pelagic larvae, six as juveniles and three as adults. There was a general trend of increasing spring–summer abundance of both larvae and juveniles, followed by a sharp winter decrease, mainly of larval flatfishes. The Lima estuary was used by Solea senegalensis, Platichthys flesus and Solea solea as a nursery area, with direct settlement for the two first species. In contrast, indirect settlement was suggested for S. solea, with metamorphosis occurring outside the estuarine area. Estuarine recruitment of S. senegalensis varied between years, with young larvae occurring in the estuary throughout a prolonged period that lasted 6–9 months, corroborating the protracted spawning season. P. flesus, the second most abundant species, exhibited a typical spring estuarine recruitment, without inter-annual variations. Developed larvae arrived in the estuary during spring, whereas the 0-group juveniles emerged in the following summer period. The present study contributes new insight to our understanding of the economically important S. senegalensis, and highlights the importance of integrating the planktonic larval phase into traditional flatfish nursery studies. 相似文献
19.
Background
Reactive oxygen species (ROS) are vital regulators of many cellular functions in the body. The intracellular ROS concentration is highly regulated by a balance between pro-oxidants and anti-oxidants. A chronic excess of pro-oxidants leads to elevated ROS concentrations and inflammation, possibly initiating or enhancing disease onset. Mineral-induced generation of ROS, the role of minerals in upregulating cellular ROS, and their role in the development of several occupational diseases are now widely recognized. However, there is no standard protocol to determine changes in ROS production in cells after exposure to mineral dust or earth materials in general. In this study, a new method for determining the degree of cellular toxicity (i.e., cytotoxicity) of particles is described that will help bridge the gap in knowledge.Results
By measuring the production of ROS and the viability of cells, an inflammatory stress response (ISR) indicator is defined. This approach normalizes the ROS upregulation with respect to the number of viable cells at the time of measurement. We conducted experiments on a series of minerals and soils that represent materials that are inert (i.e., glass beads, anatase, and a soil with low trace element content), moderately reactive (i.e., soil with high trace element content), and highly reactive (i.e., pyrite). Inert materials generated the lowest ISR, averaging 350% compared to the control. Acid washed pyrite produced the highest ISR (1,100 fold higher than the control). The measurements conducted as a function of time showed a complex response. Most materials showed an increase in ISR with particle loading.Conclusions
The amount of cellularly generated ROS and cell viability combined provide a better understanding of particle-induced oxidative stress. The results indicate that some earth materials may solicit an initial burst of ROS, followed by a second phase in which cell viability decreases and ROS production increases, leading to a high ISR value. Hence, measurements conducted over a range of particle loading combined with multiple data measurements up to 24 hours can provide new insights in the possible effect of exposure to earth materials on human health. 相似文献20.
The abundant iron sulfide mineral pyrite has been shown to catalytically produce hydrogen peroxide (H2O2) and hydroxyl radical ( . OH) in slurries of oxygenated water. Understanding the formation and fate of these reactive oxygen species is important to biological and ecological systems as exposure can lead to deleterious health effects, but also environmental engineering during the optimization of remediation approaches for possible treatment of contaminated waste streams. This study presents the use of the amino acid phenylalanine (Phe) to monitor the kinetics of pyrite-induced . OH formation through rates of hydroxylation forming three isomers of tyrosine (Tyr) - ortho-, meta-, and para-Tyr. Results indicate that about 50% of the Phe loss results in Tyr formation, and that these products further react with . OH at rates comparable to Phe. The overall loss of Phe appeared to be pseudo first-order in [Phe] as a function of time, but for the first time it is shown that initial rates were much less than first-order as a function of initial substrate concentration, [Phe]o. These results can be rationalized by considering that the effective concentration of . OH in solution is lower at a higher level of reactant and that an increasing fraction of . OH is consumed by Phe-degradation products as a function of time. A simplified first-order model was created to describe Phe loss in pyrite slurries which incorporates the [Phe]o, a first-order dependence on pyrite surface area, the assumption that all Phe degradation products compete equally for the limited supply of highly reactive . OH, and a flux that is related to the release of H2O2 from the pyrite surface (a result of the incomplete reduction of oxygen at the pyrite surface). An empirically derived rate constant, K pyr , was introduced to describe a variable . OH-reactivity for different batches of pyrite. Both the simplified first-order kinetic model, and a more detailed numerical simulation, yielded results that compare well to the observed kinetic data describing the effects of variations in concentrations of both initial Phe and pyrite. This work supports the use of Phe as a useful probe to assess the formation of . OH in the presence of pyrite, and its possible utility for similar applications with other minerals. 相似文献