Impact of fluvial flooding on potentially toxic element mobility in floodplain soils 

2021 ◽  
Author(s):  
Jessica Ponting ◽  
Anne Verhoef ◽  
Michael Watts ◽  
Tom Sizmur
Keyword(s):  
Chemical Elements ◽  
Ecological Impacts ◽  
Reductive Dissolution ◽  
Climate Projections ◽  
Pore Waters ◽  
Floodplain Soil ◽  
Soil Redox Potential ◽  
Floodplain Soils ◽  
Flooding Event ◽  
Urban Catchments

<p>Climate projections suggest that rainfall events will become more frequent and intense, which may lead to more widespread flooding. Floodplains can be used to help reduce the magnitude of floods downstream by storing excess flood water, thus making them useful for flood risk management. This means that floodplains are subjected to repeated drying and rewetting, which has implications for biogeochemical cycling of chemical elements in floodplain soils.</p><p>Floodplains have been considered a sink for contaminants in urban catchments, where high river flows transport contaminated sediments downstream and deposit them onto the floodplain topsoil. With increasing flooding frequency and duration, floodplains may become sources of legacy pollution through desorption of contaminants into soil porewater or resuspension of particulate matter into the overlying floodwater. Therefore, flooding could re-mobilise potentially toxic elements (PTEs) such as Cadmium (Cd), Copper (Cu), Chromium (Cr), Nickel (Ni), and Lead (Pb) that are present in the floodplain soil as a result of historic deposition. Mobilising PTEs in floodplain soils may cause adverse ecological impacts for soil microorganisms, plants, and both terrestrial and aquatic fauna.</p><p>The mobility of PTEs from the floodplain soil can increase or decrease due to the net effect of five key processes that influence dispersion and accumulation; 1) soil redox potential for which decreases  can directly alter the speciation, and hence mobility, of redox sensitive PTEs (e.g. As and Cr), 2) soil pH for which an increase usually reduces the mobility of metal cations (e.g. Cd<sup>2+</sup>, Cu<sup>2+</sup>, Ni<sup>2+</sup>, Pb<sup>2+</sup>), 3) dissolved organic matter which can mobilise PTEs were strongly bound to soil particles, 4) iron (Fe) and manganese (Mn) hydroxides undergo reductive dissolution, releasing adsorbed and co-precipitated PTEs, and 5) reduction of sulphate which immobilises PTEs due to precipitation of metal sulphides.</p><p>We took a field-based approach; extracting soil pore waters from a floodplain downstream of a typical urban catchment in southeast England before, during and after a flooding event. During the flood, there was increased mobility of Cd and Pb, and decreased mobility for Cu and Cr, compared to the mobility before flooding. After the flood, Ni mobility increased, whereas the other PTEs had lower mobility than they had prior to the flood. We also measured explanatory variables (e.g. pH, redox, Fe and Mn) that might explain the changes in mobility of PTEs that we found. Reductive dissolution of Mn is a possible mechanism for the increased mobility of Cd and Pb and redox likely played a role in the reduced Cr mobility.</p><p>Flooding did not influence the mobility of all PTEs in the same way. The duration of flooding is thought to influence the mobilisation due to the length of time for key processes to take place. It is therefore difficult to predict what PTEs might be mobilised into the environment with any given flooding event, further work is required to identify which soil properties should be measured in order to improve our capability to predict how a flooding event will influence the mobility of individual PTEs in geochemically contrasting floodplain soils.</p>

scholarly journals Incubation Studies on Exchangable Zn for Varying Levels of added Zn Under Aerobic and Anaerobic Conditions in Grey Terrace Soils, Non Calcarious Floodplain Soils and Calcarious Floodplain Soils

2013 ◽  
Vol 9 (1-2) ◽  
pp. 9-15 ◽  
Author(s):  
KH Talukder ◽  
IU Ahmed ◽  
MS Islam ◽  
MS Islam ◽  
M Asaduzzaman ◽  
...  
Keyword(s):  
Anaerobic Condition ◽  
Early Stage ◽  
Aerobic Condition ◽  
Anaerobic Conditions ◽  
Floodplain Soil ◽  
Zinc Fractions ◽  
Floodplain Soils ◽  
Soil Zn ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

Fractions studies were done to know how the zinc applied to different soils was distributed in to various fractions when the soils incubated under aerobic and anaerobic condition. The added zinc provided significant increase in exchangeable Zn both under aerobic and anaerobic conditions although anaerobic condition gave lower results than aerobic condition. The higher results were obtained at early stage of incubation and it gradually reduced as the incubation period proceeded to 90 days. These results showed all most similar trends for all the soils under study. In general, added zinc showed significantly higher results to the different fractions of soil Zn both under anaerobic and aerobic incubation with very few exceptions. The highest amount of added Zn (12 kg/ha) always produced greater results than the lower doses. Only exchangeable Zn was found higher in the 1st measurement at 15 DAI then gradually decreased but in other cases, gradual increase in zinc fractions was seen as the incubation study proceed to longer duration provided with very few exceptions. In many cases, the exchangeable-Zn found higher only at 15 DAI but sharply reduced at 30 DAI. In general, the Gray Terrace Soil produced the highest results followed by Non Calcareous Gray Floodplain and the lowest results were observed in Dark Grey Floodplain & Brown Floodplain Soil. DOI: http://dx.doi.org/10.3329/jsf.v9i1-2.14643 J. Sci. Foundation, 9(1&2): 9-15, June-December 2011

scholarly journals Geomorphic regulation of floodplain soil organic carbon concentration in watersheds of the Rocky and Cascade Mountains, USA

2018 ◽  
Vol 6 (4) ◽  
pp. 1101-1114 ◽  
Author(s):  
Daniel N. Scott ◽  
Ellen E. Wohl
Keyword(s):  
Organic Carbon ◽  
Spatial Scales ◽  
Dominant Role ◽  
Mountain River ◽  
Cascade Mountains ◽  
Valley Bottom ◽  
Floodplain Soil ◽  
Local Factors ◽  
Floodplain Soils ◽  
Organic Carbon Concentration

Abstract. Mountain rivers have the potential to retain OC-rich soil and store large quantities of organic carbon (OC) in floodplain soils. We characterize valley bottom morphology, floodplain soil, and vegetation in two disparate mountain river basins: the Middle Fork Snoqualmie in the Cascade Mountains and the Big Sandy in the Wind River Range of the Rocky Mountains. We use this dataset to examine variability in OC concentration between these basins as well as within them at multiple spatial scales. We find that although there are some differences between basins, much of the variability in OC concentration is due to local factors, such as soil moisture and valley bottom geometry. From this, we conclude that local factors likely play a dominant role in regulating OC concentration in valley bottoms and that interbasin differences in climate or vegetation characteristics may not translate directly into differences in OC storage. We also use an analysis of OC concentration and soil texture by depth to infer that OC is input to floodplain soils mainly by decaying vegetation, not overbank deposition of fine, OC-bearing sediment. Geomorphology and hydrology play strong roles in determining the spatial distribution of soil OC in mountain river corridors.

Planning for climate change without climate projections?

2017 ◽  
Author(s):  
Joshua J. Lawler ◽  
Julia Michalak
Keyword(s):  
Climate Change ◽  
Climate Modeling ◽  
Ecological Impacts ◽  
Climate Projections ◽  
Relative Uncertainty ◽  
Climate Change Projections ◽  
Climate Forecasts ◽  
The Face ◽  
Climate Change Concern ◽  
Conservation Plans

This chapter explores the relative uncertainty associated with popular approaches to conservation planning in the face of climate change. Concern about uncertainties inherent in climate-change projections and associated ecological impacts have led many in the conservation community to avoid climate modeling, and instead favor forecast-free approaches that involve increasing connectivity and protecting “nature’s stage” (geophysical settings) to produce climate-smart conservation plans. A comparison of each of these approaches reveals that the uncertainties associated with connectivity modeling and mapping geophysical settings can be as large, if not larger than, the uncertainties associated with climate-change projections. Whereas the uncertainties of climate forecasts are widely appreciated, the same cannot be said for the approaches that avoid climate forecasts. It is not the case that there is one best approach. The answer to uncertainty is to seek robust conservation plans that work regardless of which approach is taken.

scholarly journals Phosphorus Fractionations in Ganges Tidal Floodplain Soil of Bangladesh

2016 ◽  
Vol 19 (2) ◽  
pp. 57-63
Author(s):  
MF Hoque ◽  
MS Islam ◽  
MR Islam ◽  
MH Rashid ◽  
MA Saleque
Keyword(s):  
Relative Concentration ◽  
Relative Proportion ◽  
Residual Fraction ◽  
Organic P ◽  
Floodplain Soil ◽  
Inorganic P ◽  
Floodplain Soils ◽  
Fe Content ◽  
Labile Pool ◽  
Soil Solution P

CORRECTION: Due to a number of formatting and layout issues, the PDF of this paper was replaced on 10th October 2016. The page numbers of this article have changed from 55-61 to 57-63.The present investigation aimed to evaluate different fractions of P of Ganges tidal floodplain soils of Bangladesh in terms of plant availability in the selected soil. The samples were analyzed for solution P, labile pool, alkali-extracted inorganic pool, organic pool, acidic pool and residual P.The soil solution P in the tested soils ranged from 0.03 to 0.11 mg L–1. The concentration of 0.5M NaHCO3 extracted P had a range of 8-34 mg kg–1. Dilute NaOH extracted inorganic P had a range of 25-59 mg kg–1. NaOH extracted organic P ranged from 334 to 542 mg kg–1 and acid extracted P represented from 140 to 443 mg kg–1, respectively. Residual P of the tested soils showed a concentration of 104-262 mg kg–1. On average of the 12 soils, the relative concentration of solution P was 0.01%, NaHCO3 P was 3.2%, NaOH-Pi was 6.8%, NaOH-Po was 44.6%, acid pool was 27.3% and residual fraction was 18.1%. Different P pools showed strong correlation either with sand, silt, clay, electrical conductivity, pH(H2O), pH (KCl), organic carbon or extractable Fe content. The tested Ganges tidal floodplain soils demonstrated wide variation in the relative proportion of different P pools.Bangladesh Rice j. 2015, 19(2): 57-63

Mercury volatilization from a floodplain soil during a simulated flooding event

2014 ◽  
Vol 14 (9) ◽  
pp. 1549-1558 ◽  
Author(s):  
Iris Hindersmann ◽  
Jörg Hippler ◽  
Alfred V. Hirner ◽  
Tim Mansfeldt
Keyword(s):  
Floodplain Soil ◽  
Flooding Event ◽  
Mercury Volatilization

scholarly journals Uncertainty, Complexity and Constraints: How do We Robustly Assess Biological Responses Under a Rapidly Changing Climate?

2021 ◽  
Author(s):  
Imtiaz Rangwala ◽  
Wynne Moss ◽  
Jane Wolken ◽  
Renee Rondeau ◽  
Karen Newlon ◽  
...  
Keyword(s):  
Climate Change ◽  
Ecological Impacts ◽  
Expert Elicitation ◽  
Future Climate Change ◽  
Climate Projections ◽  
Ecological Processes ◽  
Changing Climate ◽  
Biological Responses ◽  
Recent Climate ◽  
Spatiotemporal Scales

How robust is our assessment of impacts to ecosystems and species from a rapidly changing climate during the 21st century? We examine the challenges of uncertainty, complexity and constraints associated with applying climate projections to understanding future biological responses. This includes an evaluation of how to incorporate the uncertainty associated with different greenhouse gas emissions scenarios and climate models, and constraints of spatiotemporal scales and resolution of climate data into impact assessments. We describe the challenges of identifying relevant climate metrics for ecological models and evaluate the usefulness and limitations of different methodologies of applying climate change to both quantitative and qualitative ecological response models. We discuss the importance of incorporating extreme climate events and their stochastic tendencies in assessing ecological impacts and transformation, and provide recommendations for better integration of complex climate-ecological interactions at relevant spatiotemporal scales. We further recognize the compounding nature of uncertainty when accounting for our limited understanding of the interactions between climate and biological processes. Given the inherent complexity in ecological processes and their interactions with climate, we recommend integrating quantitative modeling with expert elicitation from diverse disciplines and experiential understanding of recent climate-driven ecological processes to develop more robust understanding of ecological responses under different scenarios of future climate change. Inherently complex interactions between climate and biological systems also provide an opportunity to develop wide-ranging strategies that resource managers can employ to prepare for the future.

scholarly journals Uncertainty, Complexity and Constraints: How Do We Robustly Assess Biological Responses under a Rapidly Changing Climate?

Climate ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 177
Author(s):  
Imtiaz Rangwala ◽  
Wynne Moss ◽  
Jane Wolken ◽  
Renee Rondeau ◽  
Karen Newlon ◽  
...  
Keyword(s):  
Climate Change ◽  
Ecological Impacts ◽  
Expert Elicitation ◽  
Future Climate Change ◽  
Climate Projections ◽  
Ecological Processes ◽  
Changing Climate ◽  
Biological Responses ◽  
Recent Climate ◽  
Spatiotemporal Scales

How robust is our assessment of impacts to ecosystems and species from a rapidly changing climate during the 21st century? We examine the challenges of uncertainty, complexity and constraints associated with applying climate projections to understanding future biological responses. This includes an evaluation of how to incorporate the uncertainty associated with different greenhouse gas emissions scenarios and climate models, and constraints of spatiotemporal scales and resolution of climate data into impact assessments. We describe the challenges of identifying relevant climate metrics for biological impact assessments and evaluate the usefulness and limitations of different methodologies of applying climate change to both quantitative and qualitative assessments. We discuss the importance of incorporating extreme climate events and their stochastic tendencies in assessing ecological impacts and transformation, and provide recommendations for better integration of complex climate–ecological interactions at relevant spatiotemporal scales. We further recognize the compounding nature of uncertainty when accounting for our limited understanding of the interactions between climate and biological processes. Given the inherent complexity in ecological processes and their interactions with climate, we recommend integrating quantitative modeling with expert elicitation from diverse disciplines and experiential understanding of recent climate-driven ecological processes to develop a more robust understanding of ecological responses under different scenarios of future climate change. Inherently complex interactions between climate and biological systems also provide an opportunity to develop wide-ranging strategies that resource managers can employ to prepare for the future.

scholarly journals Cryptotephra from the Icelandic Veiðivötn 1477 CE eruption in a Greenland ice core: confirming the dating of 1450s CE volcanic events and assessing the eruption's climatic impact

2020 ◽  
Author(s):  
Peter M. Abbott ◽  
Gill Plunkett ◽  
Christophe Corona ◽  
Nathan J. Chellman ◽  
Joseph R. McConnell ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Tree Ring ◽  
Chemical Elements ◽  
Climatic Variability ◽  
Ice Core ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Ice Age ◽  
Climate Projections ◽  
Climatic Impact

Abstract. Volcanic eruptions are a key source of climatic variability and reconstructing their past impact can improve our understanding of the operation of the climate system and increase the accuracy of future climate projections. Two annually resolved and independently dated palaeoarchives – tree rings and polar ice cores – can be used in tandem to assess the timing, strength and climatic impact of volcanic eruptions over the past ~ 2500 years. The quantification of post-volcanic climate responses, however, has at times been hampered by differences between simulated and observed temperature responses that raised questions regarding the robustness of the chronologies of both archives. While many chronological mismatches have been resolved, the precise timing and climatic impact of one or more major sulphate emitting volcanic eruptions during the 1450s CE, including the largest atmospheric sulphate loading event in the last 700 years, has not been constrained. Here we explore this issue through a combination of tephrochronological evidence and high-resolution ice-core chemistry measurements from the TUNU2013 ice core. We identify tephra from the historically dated 1477 CE eruption of Veiðivötn-Bárðarbunga, Iceland, in direct association with a notable sulphate peak in TUNU2013 attributed to this event, confirming that it can be used as a reliable and precise time-marker. Using seasonal cycles in several chemical elements and 1477 CE as a fixed chronological point shows that ages of 1453 CE and 1458/59 CE can be attributed, with a high accuracy, to two notable sulphate peaks. This confirms the accuracy of the NS1-2011 Greenland ice-core chronology over the mid- to late 15th century and corroborate the findings of recent volcanic reconstructions from Greenland and Antarctica. Overall, this implies that large-scale Northern Hemisphere climatic cooling affecting tree-ring growth in 1453 CE was caused by a Northern Hemisphere volcanic eruption in 1452 CE and then a Southern Hemisphere eruption, previously assumed to have triggered the cooling, occurred later in 1458 CE. The direct attribution of the 1477 CE sulphate peak to the eruption of Veiðivötn, the most explosive from Iceland in the last 1200 years, also provides the opportunity to assess its climatic impact. A tree-ring based reconstruction of Northern Hemisphere summer temperatures shows a cooling of −0.35 °C in the aftermath of the eruption, the 356th coldest summer since 500 CE, a relatively weak and spatially incoherent climatic response in comparison to the less explosive but longer-lasting Icelandic Eldgjá 939 CE and Laki 1783 CE eruptions, that ranked as the 205th and 9th coldest summers respectively. In addition, the Veiðivötn 1477 CE eruption occurred around the inception of the Little Ice Age and could be used as a chronostratigraphic marker to constrain the phasing and spatial variability of climate changes over this transition if it can be traced into more regional palaeoclimatic archives.

scholarly journals Modulation of the vertical particle transfer efficiency in the oxygen minimum zone off Peru

2018 ◽  
Vol 15 (16) ◽  
pp. 5093-5111 ◽  
Author(s):  
Marine Bretagnon ◽  
Aurélien Paulmier ◽  
Véronique Garçon ◽  
Boris Dewitte ◽  
Séréna Illig ◽  
...  
Keyword(s):  
Chemical Elements ◽  
Sediment Traps ◽  
Early Spring ◽  
Transfer Efficiency ◽  
Late Winter ◽  
High Temporal Resolution ◽  
Climate Projections ◽  
Vertical Transfer ◽  
Earth’S System ◽  
Oxygen Minimum

Abstract. The fate of the organic matter (OM) produced by marine life controls the major biogeochemical cycles of the Earth's system. The OM produced through photosynthesis is either preserved, exported towards sediments or degraded through remineralisation in the water column. The productive eastern boundary upwelling systems (EBUSs) associated with oxygen minimum zones (OMZs) would be expected to foster OM preservation due to low O2 conditions. But their intense and diverse microbial activity should enhance OM degradation. To investigate this contradiction, sediment traps were deployed near the oxycline and in the OMZ core on an instrumented moored line off Peru. Data provided high-temporal-resolution O2 series characterising two seasonal steady states at the upper trap: suboxic ([O2]<25 µmol kg−1) and hypoxic–oxic (15<[O2]<160 µmol kg−1) in austral summer and winter–spring, respectively. The OMZ vertical transfer efficiency of particulate organic carbon (POC) between traps (Teff) can be classified into three main ranges (high, intermediate, low). These different Teff ranges suggest that both predominant preservation (high Teff>50 %) and remineralisation (intermediate Teff 20 < 50 % or low Teff<6 %) configurations can occur. An efficient OMZ vertical transfer (Teff>50 %) has been reported in summer and winter associated with extreme limitation in O2 concentrations or OM quantity for OM degradation. However, higher levels of O2 or OM, or less refractory OM, at the oxycline, even in a co-limitation context, can decrease the OMZ transfer efficiency to below 50 %. This is especially true in summer during intraseasonal wind-driven oxygenation events. In late winter and early spring, high oxygenation conditions together with high fluxes of sinking particles trigger a shutdown of the OMZ transfer (Teff<6 %). Transfer efficiency of chemical elements composing the majority of the flux (nitrogen, phosphorus, silica, calcium carbonate) follows the same trend as for carbon, with the lowest transfer level being in late winter and early spring. Regarding particulate isotopes, vertical transfer of δ15N suggests a complex pattern of 15N impoverishment or enrichment according to Teff modulation. This sensitivity of OM to O2 fluctuations and particle concentration calls for further investigation into OM and O2-driven remineralisation processes. This should include consideration of the intermittent behaviour of OMZ towards OM demonstrated in past studies and climate projections.

scholarly journals Meanders as a scaling motif for understanding of floodplain soil microbiome and biogeochemical potential at the watershed scale

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Paula B. Matheus Carnevali ◽  
Adi Lavy ◽  
Alex D. Thomas ◽  
Alexander Crits-Christoph ◽  
Spencer Diamond ◽  
...  
Keyword(s):  
Ammonia Oxidation ◽  
Nitrogen Compound ◽  
Nitrite Reduction ◽  
Soil Microbiome ◽  
Metabolic Potential ◽  
Floodplain Soil ◽  
Core Microbiome ◽  
East River ◽  
Floodplain Soils ◽  
Nitrate And Nitrite

Abstract Background Biogeochemical exports from watersheds are modulated by the activity of microorganisms that function over micron scales. Here, we tested the hypothesis that meander-bound regions share a core microbiome and exhibit patterns of metabolic potential that broadly predict biogeochemical processes in floodplain soils along a river corridor. Results We intensively sampled the microbiomes of floodplain soils located in the upper, middle, and lower reaches of the East River, Colorado. Despite the very high microbial diversity and complexity of the soils, we reconstructed 248 quality draft genomes representative of subspecies. Approximately one third of these bacterial subspecies was detected across all three locations at similar abundance levels, and ~ 15% of species were detected in two consecutive years. Within the meander-bound floodplains, we did not detect systematic patterns of gene abundance based on sampling position relative to the river. However, across meanders, we identified a core floodplain microbiome that is enriched in capacities for aerobic respiration, aerobic CO oxidation, and thiosulfate oxidation with the formation of elemental sulfur. Given this, we conducted a transcriptomic analysis of the middle floodplain. In contrast to predictions made based on the prominence of gene inventories, the most highly transcribed genes were relatively rare amoCAB and nxrAB (for nitrification) genes, followed by genes involved in methanol and formate oxidation, and nitrogen and CO2 fixation. Within all three meanders, low soil organic carbon correlated with high activity of genes involved in methanol, formate, sulfide, hydrogen, and ammonia oxidation, nitrite oxidoreduction, and nitrate and nitrite reduction. Overall, the results emphasize the importance of sulfur, one-carbon and nitrogen compound metabolism in soils of the riparian corridor. Conclusions The disparity between the scale of a microbial cell and the scale of a watershed currently limits the development of genomically informed predictive models describing watershed biogeochemical function. Meander-bound floodplains appear to serve as scaling motifs that predict aggregate capacities for biogeochemical transformations, providing a foundation for incorporating riparian soil microbiomes in watershed models. Widely represented genetic capacities did not predict in situ activity at one time point, but rather they define a reservoir of biogeochemical potential available as conditions change.

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