Metal accumulation in American wild celery (Vallisneria americana Michx.) in the St. Lawrence River: effects of water depth and exposure to current

1998 ◽  
Vol 55 (10) ◽  
pp. 2317-2328 ◽  
Author(s):  
Christiane Hudon
Keyword(s):  
Aquatic Vegetation ◽  
Plant Biomass ◽  
Incident Light ◽  
Sampling Strategy ◽  
Open Water ◽  
Plant Tissues ◽  
Vallisneria Americana ◽  
Metal Concentrations ◽  
St Lawrence River

The sensitivity of Vallisneria americana Michx. as an indicator species of metal concentrations was assessed through the examination of its spatial (between- and within-site) and temporal (short- and long-term) variability. Eight macrophyte beds located in the St. Lawrence and Ottawa rivers were selected to contrast metal concentrations found in plants exposed to different types of waters, upstream and downstream of their confluence, in the Greater Montreal urban area. Comparisons among sites revealed higher metal concentrations, both in water and in plant tissues, at sites exposed to Ottawa River "brown" waters than at sites exposed to St. Lawrence River "green" waters. Within each site, samples represented a broad range in terms of water depths, exposure to current, incident light intensity, and total plant biomass. At all sites, metal concentrations in plant tissues were lowest in the shallow water found in sheltered, dense beds of submerged aquatic vegetation and increased in deep, open-water areas beyond the limits of dense vegetation. This persistent gradient may result from local differences in plant growth rates, exposure to currents, and (or) metal bioavailability. The use of a sampling strategy designed to control for within-site (depth-balanced) variability makes it possible to measure spatial and (or) temporal differences on the order of 20% whereas unbalanced sampling designs may lead to erroneous conclusions. Significant reductions in metal concentrations in plant tissue were observed both between 1994 and 1996 (Fe, Mn, Pb, Zn, N) and between 1976 and 1996 (Cd, Cr, Pb, Zn, N). Particular care must be given to sampling design if V. americana is to be used as a biological indicator of further long-term reductions in metal concentrations.

Bioavailability of sediment-bound metals for Vallisneria americana Michx, a submerged aquatic plant, in the St. Lawrence River

2000 ◽  
Vol 57 (7) ◽  
pp. 1330-1341 ◽  
Author(s):  
Louise St-Cyr ◽  
Peter GC Campbell
Keyword(s):  
Metal Ion ◽  
Aquatic Plant ◽  
Sediment Geochemistry ◽  
Vallisneria Americana ◽  
Point Source Pollution ◽  
Metal Concentrations ◽  
Submerged Aquatic Plant ◽  
Free Metal ◽  
Sediment Interface ◽  
St Lawrence River

We have assessed the bioavailability of sediment-bound metals (Cd, Cr, Cu, Ni, Pb, and Zn) in the St. Lawrence River using a rooted aquatic plant, Vallisneria americana Michx, as the biomonitor species. The host sediments were subjected to a sequential leaching procedure to determine the partitioning of the metals present in the surficial oxic stratum; previously published equations were then used to estimate the free metal ion concentrations at the root-sediment interface. Suspected metal accumulation in foliage from point-source pollution of the water column obscured sediment-plant relationships at several sampling stations, but in general, plant metal concentrations could be predicted on the basis of sediment geochemistry (including sediment metal concentrations). Metal concentrations in Vallisneria tissues correlated more closely with estimates of bioavailable sediment-bound metal than with total metal concentrations in sediments, particularly for Cd, Pb, and Zn. Roots proved to be better bioindicator organs than shoots for monitoring sediment contamination. Overall, the results demonstrate that Vallisneria would be a useful biomonitor species of metal contamination in the St. Lawrence River.

Domain shifts in the aquatic vegetation of shallow urban lakes: the relative roles of low light and anoxia in the catastrophic loss of the submerged angiosperm Vallisneria americana

2004 ◽  
Vol 55 (8) ◽  
pp. 749 ◽  
Author(s):  
Kay Morris ◽  
Katherine A. Harrison ◽  
Paul C. E. Bailey ◽  
Paul I. Boon
Keyword(s):  
Dissolved Oxygen ◽  
Aquatic Vegetation ◽  
Plant Biomass ◽  
Light Attenuation ◽  
Field Trials ◽  
Vallisneria Americana ◽  
Low Light ◽  
Shade Cloth ◽  
Eastern Australia ◽  
Catastrophic Loss

The catastrophic loss of Vallisneria americana from a shallow urban lake in south-eastern Australia following nutrient enrichment has been reported previously. Two experiments are reported here to determine whether light attenuation or shifts in dissolved oxygen were more important in mediating this loss of submerged plants. The first experiment tested the response of dense beds of Vallisneria to different levels of shade in the field. The second tested the effect of (i) shading and (ii) anoxia on the performance of Vallisneria grown in the glasshouse. In the field, plants persisted after 3 months beneath 100% shade cloth, although with significantly reduced biomass (63%). In contrast, plant biomass beneath 70% shade cloth was reduced by only 9%. The field trials indicate that Vallisneria is highly tolerant to severe light attenuation. In the glasshouse, microcosms that were not artificially aerated become anoxic, and all plants died within 24 days in two of the three replicate microcosms. In shaded microcosms that were artificially aerated, plant biomass was reduced by 48% but no plants died. Severe reductions in dissolved oxygen associated with shading were primarily responsible for the rapid loss of Vallisneria, rather than light attenuation alone was concluded from the current study.

Impact of water level fluctuations on St. Lawrence River aquatic vegetation

1997 ◽  
Vol 54 (12) ◽  
pp. 2853-2865 ◽  
Author(s):  
Christiane Hudon
Keyword(s):  
Water Level ◽  
Aquatic Vegetation ◽  
Plant Biomass ◽  
Plant Cover ◽  
Negative Relationship ◽  
Climatic Conditions ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Vertical Range ◽  
St Lawrence River

Historical records of average seasonal water levels in the St. Lawrence River over the past 80 years reveal cyclic variations of up to 1 m above (1976) and 1 m below (1965) present levels. These variations are probably related to climatic conditions in the basin. Over the same period, the vertical range of seasonal water levels decreased from 2.2 to 1.5 m because of discharge regulation. Exposure of new substrate during periods of extreme low water levels may facilitate the invasion of aggressive and (or) exotic species. In Lake Saint-Pierre, a strong negative relationship was observed between seasonal water level and the percentage of emergent plant cover. Under low water levels, the lake becomes a large (387 km2) marshland that could support a high plant biomass (286 times 103 t) whereas under high water levels, the lake shifts to a vast (501 km2) open-water body with a lower predicted plant biomass (117 times 103 t). A model of the major anthropic and climatic forces acting on water levels is also presented; it describes aquatic plant biomass allocation and species diversity under different water level conditions.

scholarly journals Key factors influencing metal concentrations in sediments along Western European Rivers: A long-term monitoring study (1945–2020)

2022 ◽  
Vol 805 ◽  
pp. 149778
Author(s):  
André-Marie Dendievel ◽  
Cécile Grosbois ◽  
Sophie Ayrault ◽  
Olivier Evrard ◽  
Alexandra Coynel ◽  
...  
Keyword(s):  
Key Factors ◽  
Metal Concentrations ◽  
Factors Influencing ◽  
Monitoring Study ◽  
Long Term Monitoring ◽  
Western European ◽  
Term Monitoring

scholarly journals Lead, zinc, and chromium concentrations in acidic headwater streams in Sweden explained by chemical, climatic, and land-use variations

2012 ◽  
Vol 9 (11) ◽  
pp. 4323-4335 ◽  
Author(s):  
B. J. Huser ◽  
J. Fölster ◽  
S. J. Köhler
Keyword(s):  
Land Use ◽  
Predictive Power ◽  
Prediction Models ◽  
Headwater Streams ◽  
Data Series ◽  
Seasonal Differences ◽  
Metal Concentrations ◽  
Lead Zinc ◽  
Term Data

Abstract. Long-term data series (1996–2009) for eleven acidic headwater streams (< 10 km2) in Sweden were analyzed to determine factors controlling concentrations of trace metals. In-stream chemical data as well climatic, flow, and deposition chemistry data were used to develop models predicting concentrations of chromium (Cr), lead (Pb), and zinc (Zn). Data were initially analyzed using partial least squares to determine a set of variables that could predict metal concentrations across all sites. Organic matter (as absorbance) and iron related positively to Pb and Cr, while pH related negatively to Pb and Zn. Other variables such as conductivity, manganese, and temperature were important as well. Multiple linear regression was then used to determine minimally adequate prediction models which explained an average of 35% (Cr), 52% (Zn), and 72% (Pb) of metal variation across all sites. While models explained at least 50% of variation in the majority of sites for Pb (10) and Zn (8), only three sites met this criterion for Cr. Investigation of variation between site models for each metal revealed geographical (altitude), chemical (sulfate), and land-use (silvaculture) influences on predictive power of the models. Residual analysis revealed seasonal differences in the ability of the models to predict metal concentrations as well. Expected future changes in model variables were applied and results showed the potential for long-term increases (Pb) or decreases (Zn) for trace metal concentrations at these sites.

scholarly journals Do soil bacterial communities respond differently to abrupt or gradual additions of copper?

2018 ◽  
Vol 95 (1) ◽  
Author(s):  
Michael McTee ◽  
Lorinda Bullington ◽  
Matthias C Rillig ◽  
Philip W Ramsey
Keyword(s):  
Heavy Metals ◽  
Soil Respiration ◽  
Microbial Communities ◽  
Bacterial Communities ◽  
Diversity Indices ◽  
Microbial Populations ◽  
Metal Concentrations ◽  
Soil Bacterial Communities ◽  
Bacterial Richness

ABSTRACTMany experiments that measure the response of microbial communities to heavy metals increase metal concentrations abruptly in the soil. However, it is unclear whether abrupt additions mimic the gradual and often long-term accumulation of these metals in the environment where microbial populations may adapt. In a greenhouse experiment that lasted 26 months, we tested whether bacterial communities and soil respiration differed between soils that received an abrupt or a gradual addition of copper or no copper at all. Bacterial richness and other diversity indices were consistently lower in the abrupt treatment compared to the ambient treatment that received no copper. The abrupt addition of copper yielded different initial bacterial communities than the gradual addition; however, these communities appeared to converge once copper concentrations were approximately equal. Soil respiration in the abrupt treatment was initially suppressed but recovered after four months. Afterwards, respiration in both the gradual and abrupt treatments wavered between being below or equal to the ambient treatment. Overall, our study indicates that gradual and abrupt additions of copper can yield similar bacterial communities and respiration, but these responses may drastically vary until copper concentrations are equal.

scholarly journals Modern condition and analysis of anthropogenous-climatic transformation of vegetation of lakes of the northern Steppe land

2018 ◽  
Vol 29 (2) ◽  
Author(s):  
N. O. Roshchyna
Keyword(s):  
Aquatic Ecosystems ◽  
Aquatic Vegetation ◽  
Snow Accumulation ◽  
Floodplain Lakes ◽  
Anthropogenic Factors ◽  
Chemical Pollution ◽  
Ecological Groups ◽  
Adventive Species ◽  
Higher Aquatic Vegetation

In this article, the current and former distribution of higher aquatic vegetation has been analyzed for floodplain lakes, arenas lakes and third terraces lakes in the valleys of large and medium North-Steppe Dnieper rivers. The article is devoted to the current state analysis of the higher aquatic vegetation at North-Steppe Dnieper lakes, its dynamics over a long-term period, as well as the determination of the nature and extent of anthropogenic-climatic changes in vegetation. Anthropogenic influence is a major threat to the development and functioning of most aquatic ecosystems. Since the twentieth century, it has been intensified by trends to long-term climate changes, which are also largely result of human activity. Increasing temperature of the winter season does not contribute to snow accumulation. Reduction of snow accumulation (frequent thaws during the winter), regulation of river flow (formation of a reservoirs cascade and ponds) and accumulation of melt water in artificial reservoirs led to the smoothing of the peak of the spring flood. Thus, the factor that provided spring washing of floodplain lakes, limited their overgrowing by air-water vegetation and their waterlogging disappeared. The anthropogenic factors that influence negatively include: intensification of agriculture, plowing of coastal areas, unreasonable land reclamation, overgrazing, development of transport and engineering infrastructure, urbanization, recreation, and chemical pollution. The presented data was obtained on the basis of processing our own research materials of 2009–2018 and literary and archival materials analysis (the herbarium of the Dnipropetrovs’k National University and the archive of the Research Institute of Biology). Natural Northern Steppe Dnieper lakes are located mainly in river valleys, so the study area was conventionally divided into sections: the large river valley (Dnieper) and the middle rivers valleys (Samara and Orel). Three ecological groups of macrophytes were reviewed and compared: hydatofites (submerged species), pleistophytes (species with floating leaves) and helophytes (air-water species). The vegetation of Dnieper floodplain lakes practically did not change for all three formation groups. The number of immersed plants communities within the floodplains of medium-sized rivers has decreased by three. The pleistophytes and helophytes associations decreased to fragments of associations. The lakes vegetation within the sandy Dnieper terrace practically did not change for all three formation groups. The submerged lakes plants associations within the sandy medium-sized rivers terraces have been reduced by two. As part of the lakes vegetation on the Dnipro saline terraces, fragments of associations of the two species are considered extinct. A new association of southern adventive species Ruppia maritima L. has appeared within the limits of the middle rivers saline terrace. Changes in higher aquatic vegetation are characteristic of all types of lakes. Changes occur in the direction of crowding out higher aquatic vegetation communities by airborne plant communities. The consequence of the anthropogenic-climatic transformation of aquatic ecosystems is increased mineralization, siltation, and, as a result, intensive overgrowing of lakes by aboriginal and adventive species with a wide ecological amplitude (replacement of sensitive to environmental changes species).

scholarly journals Evolution of a Biomass-Fermenting Bacterium To Resist Lignin Phenolics

2017 ◽  
Vol 83 (11) ◽  
Author(s):  
Tristan Cerisy ◽  
Tiffany Souterre ◽  
Ismael Torres-Romero ◽  
Magali Boutard ◽  
Ivan Dubois ◽  
...  
Keyword(s):  
Ferulic Acid ◽  
Plant Biomass ◽  
Consolidated Bioprocessing ◽  
Gene Dosage ◽  
Content Type ◽  
Chemical Inhibitors ◽  
Growth Selection ◽  
Clostridium Phytofermentans

ABSTRACT Increasing the resistance of plant-fermenting bacteria to lignocellulosic inhibitors is useful to understand microbial adaptation and to develop candidate strains for consolidated bioprocessing. Here, we study and improve inhibitor resistance in Clostridium phytofermentans (also called Lachnoclostridium phytofermentans), a model anaerobe that ferments lignocellulosic biomass. We survey the resistance of this bacterium to a panel of biomass inhibitors and then evolve strains that grow in increasing concentrations of the lignin phenolic, ferulic acid, by automated, long-term growth selection in an anaerobic GM3 automat. Ultimately, strains resist multiple inhibitors and grow robustly at the solubility limit of ferulate while retaining the ability to ferment cellulose. We analyze genome-wide transcription patterns during ferulate stress and genomic variants that arose along the ferulate growth selection, revealing how cells adapt to inhibitors through changes in gene dosage and regulation, membrane fatty acid structure, and the surface layer. Collectively, this study demonstrates an automated framework for in vivo directed evolution of anaerobes and gives insight into the genetic mechanisms by which bacteria survive exposure to chemical inhibitors. IMPORTANCE Fermentation of plant biomass is a key part of carbon cycling in diverse ecosystems. Further, industrial biomass fermentation may provide a renewable alternative to fossil fuels. Plants are primarily composed of lignocellulose, a matrix of polysaccharides and polyphenolic lignin. Thus, when microorganisms degrade lignocellulose to access sugars, they also release phenolic and acidic inhibitors. Here, we study how the plant-fermenting bacterium Clostridium phytofermentans resists plant inhibitors using the lignin phenolic, ferulic acid. We examine how the cell responds to abrupt ferulate stress by measuring changes in gene expression. We evolve increasingly resistant strains by automated, long-term cultivation at progressively higher ferulate concentrations and sequence their genomes to identify mutations associated with acquired ferulate resistance. Our study develops an inhibitor-resistant bacterium that ferments cellulose and provides insights into genomic evolution to resist chemical inhibitors.

Long-term phosphorus removal in Florida aquatic systems dominated by submerged aquatic vegetation

2003 ◽  
Vol 20 (1) ◽  
pp. 45-63 ◽  
Author(s):  
Robert L. Knight ◽  
Binhe Gu ◽  
Ronald A. Clarke ◽  
Jana M. Newman
Keyword(s):  
Phosphorus Removal ◽  
Submerged Aquatic Vegetation ◽  
Aquatic Vegetation ◽  
Aquatic Systems
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