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1.
In contaminated soils, efficiency of natural attenuation or engineered bioremediation largely depends on biodegradation capacities of the local microflorae. In the present study, the biodegradation capacities of various microflorae towards diesel oil were determined in laboratory conditions. Microflorae were collected from 9 contaminated and 10 uncontaminated soil samples and were compared to urban wastewater activated sludge. The recalcitrance of hydrocarbons in tests was characterised using both gas chromatography (GC) and comprehensive two-dimensional gas chromatography (GC×GC). The microflorae from contaminated soils were found to exhibit higher degradation capacities than those from uncontaminated soil and activated sludge. In cultures inoculated by contaminated-soil microflorae, 80% of diesel oil on an average was consumed over 4-week incubation compared to only 64% in uncontaminated soil and 60% in activated sludge cultures. As shown by GC, n-alkanes of diesel oil were totally utilised by each microflora but differentiated degradation extents were observed for cyclic and branched hydrocarbons. The enhanced degradation capacities of impacted-soil microflorae resulted probably from an adaptation to the hydrocarbon contaminants but a similar adaptation was noted in uncontaminated soils when conifer trees might have released natural hydrocarbons. GC×GC showed that a contaminated-soil microflora removed all aromatics and all branched alkanes containing less than C15. The most recalcitrant compounds were the branched and cyclic alkanes with 15–23 atoms of carbon. 相似文献
2.
Bachoon DS Araujo R Molina M Hodson RE 《Journal of industrial microbiology & biotechnology》2001,27(2):72-79
Microbial community dynamics in wetlands microcosms emended with commercial products (surfactant, a biological agent, and
nutrients) designed to enhance bioremediation was followed for 3 months. The effectiveness of enhanced degradation was assessed
by determining residual concentrations of individual petroleum hydrocarbons by GC/MS. The size and composition of the sediment
microbial community was assessed using a variety of indices, including bacterial plate counts, MPNs, and DNA hybridizations
with domain- and group-specific oligonucleotide probes. The addition of inorganic nutrients was the most effective treatment
for the enhancement of oil degradation, resulting in marked degradation of petroleum alkanes and a lesser extent of degradation
of aromatic oil constituents. The enhanced degradation was associated with increases in the amount of extractable microbial
DNA and Streptomyces in the sediment, although not with increased viable counts (plate counts, MPN). Bacteria introduced with one of the proprietary
products were still detected in the microcosms after 3 months, but were not a major quantitative constituent of the community.
The biological product enhanced oil degradation relative to the control, but to a lesser extent than the nutrient additions
alone. In contrast, application of the surfactant to the oil-impacted sediment decreased oil degradation. Journal of Industrial Microbiology & Biotechnology (2001) 27, 72–79.
Received 18 March 2001/ Accepted in revised form 09 June 2001 相似文献
3.
Biogeographic Variation of Foliar n‐Alkanes of Juniperus communis var. saxatilis Pallas from the Balkans
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Nemanja Rajčević Pedja Janaćković Tanja Dodoš Vele Tešević Petar D. Marin 《化学与生物多样性》2014,11(12):1923-1938
The composition of the epicuticular n‐alkanes isolated from the leaves of ten populations of Juniperus communis L. var. saxatilis Pallas from central (continental) and western (coastal) areas of the Balkan Peninsula was characterized by GC‐FID and GC/MS analyses. In the leaf waxes, 14 n‐alkane homologues with chain‐lengths ranging from C22 to C35 were identified. All samples were dominated by n‐tritriacontane (C33), but differences in two other dominant n‐alkanes allowed separating the coastal from the continental populations. Several statistical methods (ANOVA, principal component, discriminant, and cluster analyses as well as the Mantel test) were deployed to analyze the diversity and variability of the epicuticular‐leaf‐n‐alkane patterns of the ten natural populations of J. communis var. saxatilis and their relation to different geographic and bioclimatic parameters. Cluster analysis showed a high correlation of the leaf‐n‐alkane patterns with the geographical distribution of the investigated samples, differentiating the coastal from the continental populations of this taxon. Several bioclimatic parameters related to aridity were highly correlated with this differentiation. 相似文献
4.
We conducted a laboratory experiment to examine how the decomposition of particulate belowground organic matter from a salt marsh is enhanced, or not, by different mixtures of crude oil, nitrogen (N), or phosphorus (P) acting individually or synergistically. The experiment was conducted in 3.8 L sampling chambers producing varying quantities of gas whose volume was used as a surrogate measure of organic decomposition under anaerobic conditions. Gas production after 28 days, from highest to lowest, was +NP = +N >>> +P, or +oil. The gas production under either +P or +oil conditions was indistinguishable from gas production in the control chamber. Nitrogen, not phosphorus, or +NP, was the dominant factor controlling organic decomposition rates in these experiments. The implication for organic salt marsh soils is that shoreline erosion is enhanced by salt marsh oiling, presumably by its toxicity, but not by its effect on the decomposition rates of plant biomass belowground. Nutrient additions, on the other hand, may compromise the soil strength, creating a stronger disparity in soil strength between upper and lower soil layers leading to marsh loss. Nutrient amendments intended to decrease oil concentration in the marsh may not have the desired effect, and are likely to decrease soil strength, thereby enhancing marsh-to-water conversions in organic salt marsh soils. 相似文献
5.
DAWN M. PLATTNER MICHAEL W. EICHHOLZ TINA YERKES 《The Journal of wildlife management》2010,74(7):1554-1558
Abstract: A bioenergetic approach has been adopted as a planning tool to set habitat management objectives by several United States Fish and Wildlife Service North American Waterfowl Management Plan Joint Ventures. A bioenergetics model can be simplified into 2 major components, energetic demand and energetic supply. Our goal was to estimate habitat-specific food availability, information necessary for estimating energy supply for black ducks (Anas rubripes) wintering on Long Island, New York, USA. We collected both nektonic and benthic samples from 85 wetland sites dispersed among 5 habitat types (salt marsh, mud flat, submersed aquatic vegetation, brackish bay, and freshwater) commonly used by black ducks in proportion to expected use. Biomass varied among habitats (F4,5 > 7.46, P < 0.03) in 2004–2005, but there was only marginal variation in 2005–2006 (F3,4 = 5.75, P = 0.06). Mud flats had the greatest biomass (1,204 kg/ha, SE = 532), followed by submersed aquatic vegetation (61 kg/ha, SE = 18), and salt marsh (34 kg/ha, SE = 6). In the second year of the study, freshwater had the greatest biomass (306 kg/ha, SE = 286), followed by mud flats (85 kg/ha, SE = 63), and salt marsh (35 kg/ha, SE = 4). Our results suggest food density on wintering grounds of black ducks on coastal Long Island is considerably lower than for dabbling ducks using inland freshwater habitats, indicating black duck populations are more likely than other species of dabbling ducks to be limited by winter habitat. We recommend targeting preservation, restoration, and enhancement efforts on salt marsh habitat. 相似文献
6.
Interactions among salt marsh plants vary geographically but not latitudinally along the California coast
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The strength of species interactions often varies geographically and locally with environmental conditions. Competitive interactions are predicted to be stronger in benign environments while facilitation is expected to be stronger in harsh ones. We tested these ideas with an aboveground neighbor removal experiment at six salt marshes along the California coast. We determined the effect of removals of either the dominant species, Salicornia pacifica, or the subordinate species on plant cover, aboveground biomass and community composition, as well as soil salinity and moisture. We found that S. pacifica consistently competed with the subordinate species and that the strength of competition varied among sites. In contrast with other studies showing that dominant species facilitate subordinates by moderating physical stress, here the subordinate species facilitated S. pacifica shortly after removal treatments were imposed, but the effect disappeared over time. Contrary to expectations based on patterns observed in east coast salt marshes, we did not see patterns in species interactions in relation to latitude, climate, or soil edaphic characteristics. Our results suggest that variation in interactions among salt marsh plants may be influenced by local‐scale site differences such as nutrients more than broad latitudinal gradients. 相似文献
7.
Two oil-polluted sediments (PD and KH) were sampled from a coastal region in Oman for the isolation of hydrocarbon-degrading bacteria and for testing different bioremediation approaches. Fourty strains were isolated, eighteen were affiliated to Marinobacter whereas the rest belonged to Pseudomonas, Halomonas, Hahella and Alcanivorax. All strains grew well at 2–7% salinity and between 20 and 60 °C. The strains exhibited a better growth on long chain than on short chain alkanes. Biostimulation and bioaugmentation were compared in both sediments and oil biodegradation was followed by measuring CO2 evolution and by gas chromatography (GC). The evolved CO2 reached 0.45 ± 0.02 and 2.23 ± 0.07 mg CO2 g−1 sediment after 88 days in the untreated PD and KH sediments, respectively. While the addition of inorganic nutrients resulted in 1.2–3.7 fold increase in CO2 evolution in both sediments, the addition of the bacterial consortium was only effective in the PD sediment. The maximum CO2 evolution was measured when both nutrients and bacteria were added and this corresponded to a total oil mineralization of 2.6 ± 0.12 and 1.49 ± 0.04% of the initial oil after 88 days in the PD and KH sediments, respectively. GC analysis confirmed the CO2 data and showed that most of the degraded compounds belonged to alkanes. We conclude that the Omani polluted sediments contain halotolerant and thermotolerant bacteria and biostimulation is more efficient than bioaugmentation for their cleanup. 相似文献
8.
Traditionally, salt marsh ecosystems were thought to be controlled exclusively by bottom–up processes. Recently, this paradigm has shifted to include top–down control as an additional primary factor regulating salt‐marsh community structure. The most recent research on consumer impacts in southern US marshes has shown that top–down forces often interact with biotic and abiotic factors, such as secondary fungal infection in grazer‐induced wounds, soil nutrients and climatic variation, to influence ecosystem structure. In a more northern salt marsh, located in New England, we examined the separate and interactive effects of nutrient availability, insect herbivory and secondary fungal infection, on growth of the foundation species, Spartina alterniflora. We used a factorial design with two levels of nutrients (control and addition) insects (control and removal) and fungi (control and removal). Nutrient addition increased plant biomass by 131% in the absence of herbivores. When insect consumers were allowed access to fertilized plots, biomass was reduced by nearly 45% when compared with treatments with nutrients and insecticide. In contrast, insect herbivores did not affect plant biomass in unfertilized control treatments. These differences suggest that consumer effects are triggered under high nutrient levels only. We also found that secondary fungal infections in grazer‐induced wounds, in contrast to lower latitude marshes, did not significantly impact primary production. Our results suggest that while New England salt marshes may typically be under bottom–up control, eutrophication can trigger dual control with inclusion of top–down regulation. However, unlike lower latitude marshes, consumer control of plant growth in northern US salt marshes is not dependent on herbivores facilitating fungal infections that then control grass growth, suggesting that the intensity of disease mediated top–down control by small grazers may be regulated by climate and/or grazer identity that co‐vary with latitude. 相似文献
9.
What confines an annual plant to two separate zones along coastal topographic gradients? 总被引:1,自引:0,他引:1
We investigated the roles of flooding, salinity, and plant competition in creating a bimodal zonation pattern of the marsh
dominant annual plant, Suaeda salsa, along coastal topographic gradients on the Pacific coast of northern China. In two consecutive years, we manipulated salinity
and flooding, salinity, and competition for S. salsa seedlings that had been transplanted into the mudflat, the high marsh, and the upland, respectively. S. salsa plants that had been transplanted into the mudflat were completely eliminated in the non-elevated treatments whereas they
performed much better in the 10 cm elevated treatments, regardless of salinity treatments. Although the performance of S. salsa transplanted into the high marsh did not differ between the fresh (watered) and the salt (control) treatments, S. salsa seedling emergence in the high marsh was nearly completely inhibited in the salt treatments. In contrast, a large number
of S. salsa seedlings did emerge in the fresh treatments. S. salsa transplanted into the upland performed well when neighbors were removed, whereas it appeared to be strongly suppressed when
neighbors were present. These data indicated that flooding, salinity, and competition all played a role in determining the
zonation pattern of S. salsa. Furthermore, the importance of salinity was found to vary with life-history stage. Based on the results from these field
manipulative experiments, we suggest that the marsh plant zonation paradigm may hold true for plant distributions along landscape-scale
topographic gradients from mudflats to uplands in general. The relative importance of flooding, salinity, and competition,
however, may vary at different elevations within a site and between sites.
Handling editor: Pierluigi Viaroli 相似文献
10.
Adult and juvenile fish utilise salt marshes for food and shelter at high tide, moving into adjacent sublittoral regions during
low tide. Understanding whether there are high levels of site fidelity for different species of coastal fish has important
implications for habitat conservation and the design of marine protected areas. We hypothesised that common salt marsh fish
species would demonstrate a high site fidelity, resulting in minimal inter-marsh connectivity. Carbon (13C) and nitrogen (15N) stable isotope ratios of larvae and juveniles of five common salt marsh fish (Atherina presbyter, Chelon labrosus, Clupea harengus, Dicentrarchus labrax, Pomatoschistus microps), seven types of primary producer and seven secondary consumer food sources were sampled in five salt marshes within two
estuary complexes along the coast of south-east England. Significant differences in 13C and 15N signatures between salt marshes indicated distinct sub-populations utilising the area of estuary around each salt marsh,
and limited connectivity, even within the same estuary complex. 15N ratios were responsible for the majority of inter-marsh differences for each species and showed similar site-specific patterns
in ratios in primary producers, secondary consumers and fish. Fish diets (derived from isotope mixing models) varied between
species but were mostly consistent between marsh sites, indicating that dietary shifts were not the source of variability
of the inter-marsh isotopic signatures within species. These results demonstrate that for some common coastal fish species,
high levels of site fidelity result in individual salt marshes operating as discrete habitats for fish assemblages. 相似文献
11.
Oil spills may considerably damage sensitive coastal wetlands. In this study, the tolerance limits of a dominant coastal salt marsh plant, Juncus roemerianus, to diesel oil and its phytoremediation effectiveness in wetland environments were investigated in the greenhouse. J. roemerianus was transplanted into salt marsh sediment contaminated with diesel fuel at concentrations of 0, 20, 40, 80, 160, 320, and 640 mg diesel g?1 dry sediment. Plant stem density, shoot height, aboveground biomass and belowground biomass were detrimentally impacted at high oil dosages even 1 year after transplantation. Tolerance limits were estimated between 160 and 320 mg g?1 based on various plant variables. Importantly, J. roemerianus enhanced oil degradation; at the 40 mg/g diesel dosage, concentrations of residual total petroleum hydrocarbons (TPH) in the sediment planted with J. roemerianus were significantly lower than those of unplanted sediments 1 year after treatment initiation. Furthermore, concentrations of total targeted polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in the J. roemerianus planted treatment were, respectively, about 3% and 15% of the unplanted treatment. Concentration reduction in all categories of hydrocarbons suggested that J. roemerianus effectively phytoremediated the diesel-contaminated wetlands. 相似文献
12.
The preseparator of an Andersen impactor with different coating treatments for a range of particle-size distributions was
evaluated. Limited theoretical simulations constrained by simplifying assumptions of the airflow fields in the preseparator
and upper stages of an 8-stage Andersen impactor were used to reveal low-velocity and high-pressure regions for potential
deposition. These regions were then sampled in subsequent particle deposition experiments. Disodium fluorescein aerosols were
sampled with different coating treatments of the preseparator floor. Particles collected at impactor stages determined particle
size distributions. Stage deposition was compared between different preseparator treatments (buffer and silicon oil). Collection
efficiency in the preseparator followed the pattern buffer >silicon oil >untreated. Statistical differences (P>0.05) were noted in collection efficiency of large particles (45 μm-75 μm) in the preseparator. The mass median aerodynamic
diameters and geometric standard deviations showed some statistical differences when different preseparator treatments for
large particles were used; therefore, preseparator coating was shown to influence performance and thereby estimates of particle
size by intertial impaction. 相似文献
13.
Poplar leaves, poplar bark and poplar wood were deoxy-liquefied directly in an air-proof stainless steel reactor at different temperatures. The oils from leaves at 350 °C, from bark at 400 °C and from wood at 450 °C, at which the liquid product yields were the maximum, were analyzed by GC–MS. The oils obtained from three parts of poplar tree were quite different from each other in the relative contents of their compositions. The oil from leaves was rich in hydrocarbons (alkanes: C7–C29; aromatics) and poor in phenolics, while oil from wood was rich in phenolics and poor in hydrocarbons. The oil from bark was moderate. Relative contents of hydrocarbons in the leaves oil were as high as 60.01% but decreased to 29.71% in bark oil and 11.43% in wood oil. GC analysis of gases and FT-IR, GC–MS and elemental analysis of oils were performed in this study. 相似文献
14.
Many authors have referred to the important role of vegetation in the consolidation of salt marsh sediments, but experiments
previously carried out by us have shown results that do not always agree with these statements. In other words, the type of
salt marsh surface coverage is not the main factor that contributes to the consolidation of sediments. To test this hypothesis
different Portuguese salt marsh stations (species/unvegetated areas) from two sites, Tagus estuary (Corroios and Pancas) and
Ria de Aveiro (Barra and Verdemilho), were compared to evaluate their influence on suspended matter deposition on the salt
marsh surface. A short-term sedimentation study was performed within stands of Spartina maritima, Halimione portulacoides, Sarcocornia perennis subsp. perennis and unvegetated areas, by analysing the deposition of sediment material on nylon filters anchored to the marsh surface. Numerical
results obtained from hydrodynamic models coupled to a Lagrangean module implemented for the Ria de Aveiro and the Tagus Estuary,
namely the root-mean square velocity (V
rms) and residual velocity of tides, were also used.
Average sedimentation rates (mean value between the different surface cover in a salt marsh) showed a seasonal trend more
or less defined but with significantly different values between sites and salt marshes. Sedimentation rates varied between
marshes: there are significant differences between Pancas and the other three marshes, but only significant differences in
sedimentation rates between Spartina and Sarcocornia.
Despite the important role of vegetation in the consolidation of salt marsh sediments, our results suggest that, the position
of stations and related abiotic conditions in the salt marshes are determining factors of variation to take into account in
the studies related with the stabilization and survival of salt marshes facing sea level rise.
Handling editor: P. Viaroli 相似文献
15.
The purpose of this study was to determine if and how the two genetically distinct forms, marsh and dune, of Sporobolus virginicus (L.) Kunth. tolerate anaerobic substrates. The treatments in the hydroponic study, conducted in the greenhouse for approximately 6 months, involved growing the marsh and dune forms in aerobic, anaerobic, and alternating aeration treatments. Plants were examined for morphological and physiological responses to the aeration treatments. In response to the continuous anaerobic treatment, the dune form of S. virginicus exhibited increased stolon biomass, but no difference of total biomass or rhizome aerenchyma when compared with the aerobic treatment. In response to alternating aeration, rhizome aerenchyma increased, total biomass decreased, and stolon biomass remained constant. Belowground transport of oxygen enabled the root tissue in all of the aeration treatments to maintain aerobic respiration. The marsh form grown in the alternating aeration treatment had the same total biomass but more rhizome aerenchyma when compared to the aerobic treatment. Growth in the continuous anaerobic treatment resulted in a reduction of total biomass and increased rhizome arenchyma. Marsh form roots did not appear to be respiring anaerobically or producing ethanol or additional malate at the time of harvest; however, root respiration was higher in the anaerobic and alternating treatments. The marsh and dune forms of S. virginicus were able to adjust morphologically or physiologically or to use existing morphological features to tolerate anaerobic substrates. Thus, it appears that the distribution of the two forms of S. virginicus found in coastal sand dunes and in salt marshes is not limited by differences in ability to tolerate waterlogged soils. 相似文献
16.
Mark D. Bertness Caitlin P. Brisson Tyler C. Coverdale Matt C. Bevil Sinead M. Crotty Elena R. Suglia 《Ecology letters》2014,17(7):830-835
Salt marsh habitat loss to vegetation die‐offs has accelerated throughout the western Atlantic in the last four decades. Recent studies have suggested that eutrophication, pollution and/or disease may contribute to the loss of marsh habitat. In light of recent evidence that predators are important determinants of marsh health in New England, we performed a total predator exclusion experiment. Here, we provide the first experimental evidence that predator depletion can cause salt marsh die‐off by releasing the herbivorous crab Sesarma reticulatum from predator control. Excluding predators from a marsh ecosystem for a single growing season resulted in a >100% increase in herbivory and a >150% increase in unvegetated bare space compared to plots with predators. Our results confirm that marshes in this region face multiple, potentially synergistic threats. 相似文献
17.
A basic geochemical approach has been used to study the diagenetic cycling and sediment-water exchange rates of essential nutrients at a site in a Delaware salt marsh. The pore water nutrients Si (OH)4, NH4
+, PO4
–3, and NO3
– were analyzed and compared seasonally, and potential diffusive fluxes were calculated from the corresponding pore water concentration gradients. Concurrent direct flux measurements were also made using closed chambers deployed on the salt marsh surface under ambient and controlled conditions. The differences in these two approaches allows for estimation of nutrient production and consumption in the root zone and at the salt marsh surface. Silicate and phosphate appear to be primarily geochemically controlled, while the nitrogen species undergo dynamic seasonal redox fluctuations resulting from microbial mediation (e.g., nitrification and denitrification).
Specifically: 相似文献
18.
Oil spills represent a major environmental threat to coastal wetlands, which provide a variety of critical ecosystem services to humanity. The U.S. Gulf of Mexico is a hub of oil and gas exploration activities that historically have impacted intertidal habitats such as salt marsh. Following the BP Deepwater Horizon oil spill, we sampled the terrestrial arthropod community and marine invertebrates found in stands of Spartina alterniflora, the most abundant plant in coastal salt marshes. Sampling occurred in 2010 as oil was washing ashore and a year later in 2011. In 2010, intertidal crabs and terrestrial arthropods (insects and spiders) were suppressed by oil exposure even in seemingly unaffected stands of plants; however, Littoraria snails were unaffected. One year later, crab and arthropods had largely recovered. Our work is the first attempt that we know of assessing vulnerability of the salt marsh arthropod community to oil exposure, and it suggests that arthropods are both quite vulnerable to oil exposure and quite resilient, able to recover from exposure within a year if host plants remain healthy. 相似文献
19.
Alaina B. Owens C. Edward Proffitt James B. Grace 《Wetlands Ecology and Management》2007,15(5):405-416
This paper reports on efforts to reduce woody successional growth by the native shrub Iva frutescens L. in a created salt marsh by using prescribed fire and cutting. Experimental treatments included a winter burn, cutting
plants at ground level, and a combination burn-and-cut treatment, with replicate plots of each. Iva frutescens proved to be extremely hardy, with zero mortality following the cutting, burning, or combination treatment; similar levels
of regrowth were observed for all treatments. Individual shrub response, however, was found to be related to initial plant
size, ground water level and salinity, and two fire characteristics (total heating >60°C and total heat index >60°C). Fire
severity, sediment nutrient concentrations, and other abiotic factors had no observable effects. 相似文献
20.
A. L. Pereira A. C. Figueiredo J. G. Barroso L. G. Pedro F. Carrapiço 《Plant biosystems》2013,147(2):268-274
Abstract Azolla filiculoides is an aquatic pteridophyte that may be used as animal food, biofertilizer and phytoremediation. Its volatile composition was never studied although several phytochemical analyses were performed. The volatile composition of A. filiculoides grown outdoors in a pond at the Botanical Garden of Lisbon University (BGLU) or in culture conditions as well as the effect of different harvesting times and the storage type were evaluated. The volatiles isolated by hydrodistillation and distillation‐extraction were analysed by gas chromatography and gas chromatography‐mass spectrometry. The oil of all the A. filiculoides samples studied affords a yellowish colour and an unpleasant odour in a yield of 0.01% (v/fw). Alcohols, aldehydes, alkanes and ketones dominated the culture samples, while aldehydes, alcohols, terpenoids and alkanes represented the main volatiles of the BGLU samples. Some quantitative differences were detected in seasonal and type of storage (fresh, dry or frozen at ?20°C) studies of A. filiculoides from the BGLU. The BGLU and culture volatiles showed qualitative differences: 2‐ethyl‐1‐hexanol was only identified in the fern culture, whereas acetophenone, pentylfuran, acetylpyridine and 2‐octanone were only detected in BGLU samples. The dendrogram showed two distinct clusters (culture and BGLU samples). The possible biological origin and bioactivity of some of the volatile compounds is discussed. Abbreviations: FID, flame ionization detector; i.d., internal diameter; v/fw, volume by fresh weight; GC, gas chromatography; GC‐MS, gas chromatography‐mass spectrometry; u, unified atomic mass unit 相似文献