Soil Seepage Water Research Articles

Genome streamlining in Parcubacteria transitioning from soil to groundwater

BackgroundTo better understand the influence of habitat on the genetic content of bacteria, with a focus on members of Candidate Phyla Radiation (CPR) bacteria, we studied the effects of transitioning from soil via seepage waters to groundwater on genomic composition of ultra-small Parcubacteria, the dominating CPR class in seepage waters, using genome resolved metagenomics.ResultsBacterial metagenome-assembled genomes (MAGs), (318 total, 32 of Parcubacteria) were generated from seepage waters and compared directly to groundwater counterparts. The estimated average genome sizes of members of major phyla Proteobacteria, Bacteroidota and Cand. Patescibacteria (Candidate Phyla Radiation – CPR bacteria) were significantly higher in soil-seepage water as compared to their groundwater counterparts. Seepage water Parcubacteria (Paceibacteria) exhibited 1.18-fold greater mean genome size and 2-fold lower mean proportion of pseudogenes than those in groundwater. Bacteroidota and Proteobacteria also showed a similar trend of reduced genomes in groundwater compared to seepage. While exploring gene loss and adaptive gains in closely related CPR lineages in groundwater, we identified a membrane protein, and a lipoglycopeptide resistance gene unique to a seepage Parcubacterium genome. A nitrite reductase gene was also identified and was unique to the groundwater Parcubacteria genomes, likely acquired from other planktonic microbes via horizontal gene transfer.ConclusionsOverall, our data suggest that bacteria in seepage waters, including ultra-small Parcubacteria, have significantly larger genomes and higher metabolic enrichment than their groundwater counterparts, highlighting possible genome streamlining of the latter in response to habitat selection in an oligotrophic environment.

Effects of Douglas fir cultivation in German forests on soil seepage water quantity and quality

Norway spruce (Picea abies L.) has been a key tree species and timber source in European forests the last centuries and is increasingly suffering from drought and bark beetle infestations due to climate warming. Current management options include replacing of Norway spruce monocultures with pure and mixed stands of European beech (Fagus sylvatica) that is the naturally dominating tree species in Central Europe. Additionally, Douglas fir (Psudotsuga menziesii), a tree species with high water use efficiency and drought tolerance, is being increasingly cultivated to increase the resilience of European forests and meet the future demand of conifer timber in a warming climate. We studied the seepage water quantity and quality with a particular focus on the nitrate (NO3–) concentration and N leaching under pure and mixed stands of Douglas fir, Norway spruce, and European beech at seven sites in Germany. Additionally, we investigated seepage water concentrations of SO4-S, Ca, Mg, K, Al and hydrological variables (interception, canopy throughfall, transpiration). Looking at the seepage water quantity and quality, the best management option is the cultivation of pure beech stands. However, this is associated with the well-known risk of monocultures concerning ecosystem disturbance. Beech stands showed the highest seepage water quantities and the lowest seepage water concentrations of major cations and anions, including NO3–. Seepage water quantity was the smallest under pure Douglas fir compared to spruce and beech stands. The composition effects of stand tree species on seepage water quality and nutrient leaching were site-dependent. At N-rich sites, pure Douglas fir stands showed higher seepage water NO3– concentrations than spruce and beech stands, whereas the tree species effects were small at N-poor sites. With respect to seepage water quantity and quality, cultivation of mixed Douglas fir–beech stands is a promising option for producing conifer timber and at the same time avoiding increased disturbance risks of mono-species forests under a warmer climate. Our results support the recommendation of mixed Douglas fir–beech stands based on soil quality, ecosystem resilience, and forest economic studies.

Effects of Moderate Nitrate and Low Sulphate Depositions on the Status of Soil Base Cation Pools and Recent Mineral Soil Acidification at Forest Conversion Sites with European Beech (“Green Eyes”) Embedded in Norway Spruce and Scots Pine Stands

High N depositions of past decades brought changes to European forests including impacts on forest soil nutrition status. However, the ecosystem responses to declining atmospheric N inputs or moderate N depositions attracted only less attention so far. Our study investigated macronutrient (N, S, Ca2+, Mg2+, K+) pools and fluxes at forest conversion sites over 80 years old in Central Germany with European beech (so-called “Green Eyes” (GE)). The GE are embedded in large spruce and pine stands (coniferous stands: CS) and all investigated forest stands were exposed to moderate N deposition rates (6.8 ± 0.9 kg ha−1 yr−1) and acidic soil conditions (pHH2O < 4.7). Since the understanding of forest soil chemical and macronutrient status is essential for the evaluation of forest conversion approaches, we linked patterns in water-bound nutrient fluxes (2001–2018) and in predicted macronutrient storage in the herbaceous and tree layer to patterns in litter fall (2016–2017) and in forest floor and mineral soil macronutrient stocks at GE and CS assessed in 2018. Our results exhibited 43% (Nt) and 21% (S) higher annual throughfall fluxes at CS than at GE. Seepage water at 100 cm mineral soil depth (2001–2018) of CS is characterized by up to fivefold higher NO3− (GE: 2 ± 0.7 µmolc L−1; CS: 9 ± 1.4 µmolc L−1) and sevenfold higher SO42− (GE: 492 ± 220 µmolc L−1; CS: 3672 ± 2613 µmolc L−1) concentrations. High base cation (∑ Ca2+, Mg2+, K+) concentrations in CS mineral soil seepage water (100 cm depth: 2224 ± 1297 µmolc L−1) show significant positive correlations with SO42−. Tree uptake of base cations at GE is associated especially with a Ca2+ depletion from deeper mineral soil. Foliar litter fall turns out to be the main pathway for litter base cation return to the topsoil at GE (>59%) and CS (>66%). The litter fall base cation return at GE (59 ± 6 kg ha−1 yr−1) is almost twice as large as the base cation deposition (30 ± 5 kg ha−1 yr−1) via throughfall and stemflow. At CS, base cation inputs to the topsoil via litter fall and depositions are at the same magnitude (24 ± 4 kg ha−1 yr−1). Macronutrient turnover is higher at GE and decomposition processes are hampered at CS maybe through higher N inputs. Due to its little biomass and only small coverage, the herbaceous layer at GE and CS do not exert a strong influence on macronutrient storage. Changes in soil base cation pools are tree species-, depth- and might be time-dependent, with recently growing forest floor stocks. An ongoing mineral soil acidification seems to be related to decreasing mineral soil base cation stocks (through NO3− and especially SO42− leaching as well as through tree uptake).

Speciation, distribution and migration pathways of polycyclic aromatic hydrocarbons in a typical underground river system in Southwest China

Water, colloid, and suspended particulate matter (SPM) samples were collected during one given year at two sites from the Laolongdong (LLD) underground river in Southwest China and analyzed for 16 priority polycyclic aromatic hydrocarbons (PAHs), dissolved organic carbon (DOC), and particulate organic carbon (POC). The concentrations of the SPM-associated, colloid-associated, freely dissolved, and dissolved organic matter (DOM)-associated PAHs varied from 202 to 1731 ng/L, 142 to 956 ng/L, 228 to 1280 ng/L, and 7.3 to 173 ng/L, respectively. The mean percentages of 4- and 5–6 ring PAHs showed increasing trends along the order of the dissolved phase, colloidal phase and particulate phase. The behavior and fate of PAHs influence by DOC and POC were examined. Overall, organic carbon was the primary factor controlling the environmental behaviors and fates of the 16 PAH species in the LLD underground river. POC in underground river has more lipophilicity to PAHs in this study. The correlation analysis suggested that the migration pathways of PAHs from the surface soil to the underground river through the sinkholes and soil seepage water both had important contribution during the rainy season. However, PAHs mainly transferred through soil seepage water in the form of dissolved PAHs during the dry season.

Characteristics and ecological risk assessment of polycyclic aromatic hydrocarbons in soil seepage water in karst terrains, southwest China.

Concentrations of polycyclic aromatic hydrocarbons (PAHs) in soils and soil seepage waters were analyzed along with dissolved organic carbon (DOC) to investigate the ecological risks and factors controlling the subsurface transport of PAHs in karst terrain in southwest China. The concentrations of dissolved PAHs in soil seepage water increased with depth and the mean concentrations at a depth of 80cm were relatively high (exceeding 1147ng/L). PAH composition in soil seepage water was dominated by low molecular weight (LMW) PAHs, whereas those associated with soil matrix were dominated by high molecular weight (HMW) PAHs. The results revealed that HMW PAHs in soil seepage water were closer to the equilibrium of dissolution than LMW and medium molecular weight (MMW) PAHs. However, due to the carrier functions of dissolved organic matter (DOM) for HMW PAHs, all PAHs can be continuously dissolved in the soil seepage water from soil matrix as the water moved vertical downward through the profiles. During this process, dynamic sorption and desorption processes were occurring between constituents in the soil seepage water and the soil matrix. This study demonstrates soil seepage water has posed a high risk to the groundwater, and effective protection is urgently needed.

Simplified measurement method for dissolved radio-Cs in litter and soil seepage water using copper-substituted Prussian blue

We developed a simple and rapid method for detecting dissolved radio-Cs in litter and/or soil seepage water using nonwoven fabrics impregnated with copper-substituted Prussian blue (Cu-NF). In laboratory and field experiments, litter and/or soil seepage water including dissolved radio-Cs were passed through traditional lysimeter systems combined with seven sheets of the Cu-NF. We then examined the recovery ratios of dissolved 137Cs in the Cu-NF. In the laboratory experiments with faster flow rates (11–2200 mm h−1), over 86% of the total dissolved 137Cs in litter seepage water was detected in the Cu-NF and over 82% of the collected 137Cs was present in the first three sheets. In the field experiments, 99% of the total dissolved 137Cs litter seepage water was collected in the Cu-NF and more than 96% of the collected 137Cs was present in the first three sheets. Furthermore, the recovery ratio of dissolved 137Cs increased with increasing installation Cu-NF length, probably because the packed soil in the Cu-NF lysimeter become more stable over time. Finally, because only the Cu-NF is measured, it is not necessary to undertake traditional measurement preparations such as filtration to remove particulate radio-Cs materials and evaporative concentration for low concentration of radio-Cs. As a result, we can save time and effort in measurement preparation by using the Cu-NF lysimeter method.

Soil heavy metal concentrations and their typical input and output fluxes on the southern Song-nen Plain, Heilongjiang Province, China

China's national “Multi-Purpose Regional Geochemical Survey” (MPRGS) project provided high density data (1sample/km2) for the assessment of soil heavy metal (e.g., Cd, Hg, Pb, and As) pollution in most agricultural regions in China. As a further study, the fluxes of the soil heavy metal input/output pathways (e.g., atmospheric deposition, irrigation water, fertilization, crop or pasture harvesting, seepage water, and surface water) were observed and evaluated on the southern Song-nen Plain in Heilongjiang Province. It was found that at present, greater than 95% of the total area has soil Cd, Hg, Pb, As, Cu, Zn, Ni, and Cr concentrations lower than the uncontaminated concentration limits given by Environmental Quality Standard of Soil of PR China (GB15618-1995). So, as a whole, the study area is a clean region for agricultural development. Atmospheric deposition, rather than irrigation and fertilization, is the dominant element source of the soil heavy metals (Cd, Hg, As, Cu, Pb, and Zn), accounting for 78–98% of the total input fluxes. Soil seepage water, other than harvesting and surface water runoff, is the dominant soil element output pathway. The observed fluxes from the pathways were evaluated by calculating the changes of the heavy metal concentrations caused by them given that the fluxes keep steady for a certain years, i.e., 5, 10, 15, and 20years, and there is no other potential pathways. It was shown that the soil in the study area as a whole will remain uncontaminated with little heavy metal hazards in the following decades, i.e., the observed six pathways will not cause severe accumulation or heavy metal hazards in the study area.

The impact of land use and land cover changes on solute dynamics in seepage water of soil from karst hillslopes of Southwest China

Abstract Land use and land cover changes can cause variations in terrestrial energy, water balance and availability of nutrients. To understand the role of vegetation in regulating the hydrochemistry of karst hillslopes, overland flow and soil seepage water from two hillslopes covered with and without vegetation were studied in the Huanjiang Observation and Research Station for Karst Ecosystems, Guangxi, SW China. Dissolved major ions, as well as isotopic compositions of dissolved inorganic C (DIC) were examined. Water from the vegetated control slope had higher solute concentrations (except NO 3 - ) and lower δ13C values than water from the disturbed slope. The dynamics of K+ and NO 3 - in soil water sampled in time-sequence from the control slope was different from the disturbed slope. Specifically, K+ and NO 3 - concentrations of the control slope decreased gradually over time, while K+ and NO 3 - concentrations of the disturbed slope increased, and other ionic concentrations increased in both of the slopes.

Ground‐based thermal imagery as a simple, practical tool for mapping saturated area connectivity and dynamics

AbstractThe hillslope‐riparian‐stream system is a key functional unit of catchments, yet very difficult to measure and monitor due to its tremendous complexity and high spatio‐temporal variability. Here, we present a simple and practical tool for imaging directly these hillslope‐riparian‐area connections. We used a FLIR b50 infrared camera to produce thermal images at the scale of 140 × 140 pixels over the spectral range 7·5–13 µm. Our IR imaging technique is sensitive to the upper 0·1 mm of the water column. Images were obtained from a constant position on the right bank of the Weierbach catchment in Luxembourg, at an incidence angle of approximately 45° over a 5‐week period. The study site measured 5 × 3 m. Our results show that ground‐based IR imagery can discriminate between areas with snow cover, snow melt, soil seepage, and stream water. More importantly, it can detect when and where variably saturated areas are active and when connectivity exists between the hillslope–riparian–stream system. Our proof of concept suggests that this is a simple, inexpensive technology for sequential mapping and characterisation of surface saturated areas and a useful complement to conventional tracer techniques. Copyright © 2010 John Wiley & Sons, Ltd.

Using sulfur and oxygen isotope data for sulfide oxidation assessment in the Freiberg polymetallic sulfide mine

Abstract The isotopic and chemical composition and dissolved SO 4 2 - of mine water from a mined and backfilled ore vein at the polymetallic sulfide deposit in Freiberg was used to study the SO 4 2 - sources and mixing processes. The main SO 4 2 - sources in mine water are SO 4 2 - in soil seepage water and groundwater, and sulfide oxidation. Using O- and S-isotope analysis, it has been calculated that about 50% (±10%) of SO 4 2 - in the mine water at the deepest accessible level of the ore vein originates from sulfide oxidation. A decrease in δ 34 S SO4 and δ 18 O SO4 values from 1997 to 2000/2002, in combination with lower SO 4 2 - concentrations, is attributed to a lower SO 4 2 - input from soil seepage water and ground water. Anthropogenic sources may be responsible for mine water with anomalous stable isotope compositions and concentrations of anions, and metals. Hydrochemical and stable isotope compositions of waters in the central Freiberg and Morgenstern mines were determined to evaluate whether the same trends as those described for the backfilled ore vein are observed in the mines, and what additional processes may operate on a larger geological scale. The δ 34 S SO4 and δ 18 O SO4 values of most flowing mine waters follow the mixing trend found for the backfilled ore vein. In addition to these SO 4 2 - sources, anthropogenic sources, such as sewage water and industrial wastewater, were observed to be of importance. Judging from isotope values and element concentrations, no obvious decrease in the intensity of sulfide oxidation in the non-flooded part of the Freiberg mine has occurred during the last 10 a. The dual isotope approach to determine both sulfate O- and S-isotopic compositions is useful to better constrain the sources of SO 4 2 - in mine waters and can also be used for pollution assessment (portion of SO 4 2 - formed by sulfide oxidation) in long-term observation studies.

Organically bound sulfur in refractory organic substances.

The sulfur compounds of refractory organic substances (ROS) of different origin have been characterized. Total organic sulfur was determined by elemental analysis. Sulfur-containing amino acids methionine and cystine were analyzed chromatographically after hydrolysis with HCl or by proteolytic digestion using enzymes. The results obtained from elemental analysis show that the total amount of sulfur is strongly dependent on the origin of the samples, because of different environmental factors during the formation of ROS. For naturally occurring samples isolated from soil seepage water, bog lake water and ground water the carbon-to-sulfur atomic ratios (C/S) decrease with the stage of humification, because of preferential loss of carbon. In humic acids (HA) isolated from secondary effluent the high value of the nitrogen-to-sulfur ratio (N/S) was indicative of a large amount of protein-derived nitrogen and sulfur compounds. In the solutions from acid hydrolysis the total amount of amino acid carbon related to the dissolved organic carbon (DOC) was generally less than 5%. Percentages of cystine related to all the amino acids detected were in the range 4 to 16%; methionine was below the detection limit for most samples. The results show that cystine is very important among the amino acids released. Enzymatic release generally resulted in smaller amounts of amino acids, indicating that these molecules are not only present in bioavailable protein-like structures. The data were compared with those from other approaches reported in the literature for the speciation of sulfur forms in ROS, including potentiometric titration, differential reduction methods, and spectroscopic investigations.

Arylsulfatase activities in soils of the Black Forest/Germany—seasonal variation and effect of (NH 4) 2SO 4 fertilization

Arylsulfatase activities in the soil of two high-elevation sites in the Black Forest/Germany (haplic podzol Schluchsee, dystric cambisol Villingen) were determined in quarterly intervals over a period of 24 and 30 months. Both sites are forested with Norway spruce ( Picea abies L. [Karst.]). At each study site, one untreated soil and one soil fertilized repeatedly with (NH 4) 2SO 4 (3×700 kg ha −1 in 1988, 1991, and 1994) was investigated. Arylsulfatase activities generally were highest in the forest floor, medium in the mineral topsoil and lowest in the subsoil. The small-scale (<10 m 2) spatial variability of arylsulfatase activity in most cases exceeded the seasonal variation. At Schluchsee, arylsulfatase activities tended to be lower in summer and autumn than in spring, and inversely followed the seasonal fluctuation of SO 4 2− concentration in the soil seepage water. No systematic seasonal changes in soil arylsulfatase activities were observed for Villingen, where SO 4 2− concentration in soil seepage water also showed lower seasonal variation. For more than 2 years after the third fertilizer amendment in 1994, mean arylsulfatase activities in the (NH 4) 2SO 4-fertilized soils were considerably decreased compared to the untreated soils. The decreases were largest in the forest floor (−80%), but also considerable in the mineral topsoil (−70 to −80%), and in the subsoil (−45 to −60%). The decrease in soil arylsulfatase activity after fertilization lasted considerably longer than the period of elevated SO 4 2− concentration in the soil solution. This is likely to result in decreased enzymatic ester sulfate degradation, and thus may contribute substantially to the observed accumulation of ester sulfates in B horizons of the fertilized soils.

Hydrochemical input-output budgets for a clean rain and drought experiment at Solling

In order to evaluate the response of an acidified forest ecosystem to reduced atmospheric deposition and seasonally limited water supply, hydrochemical fluxes were estimated for the roof experiments at Solling, Germany. The experiments were carried out in a 58 year-old spruce ( Picea abies (L.) Karst.) plantation from 1990 to 1994. Clean rain was applied to the soil surface by reducing the nitrogen, sulphur and proton inputs to 67%, 56% and 74% of the loads in ambient throughfall. The drought/rewetting experiment was carried out by artificially modifying weather extremes of drought and rewetting events. Hydrochemical input-output budgets, based on element fluxes in throughfall and in soil seepage water, have been established for major elements. Results show that on this highly acidified soil, atmospheric deposition widely influenced element fluxes in the soil seepage water. Consequently, hydrochemical budgets altered when inputs of acidity and nitrogen were reduced. After one year of the clean rain treatment nitrate output was considerably reduced. The nitrate and proton budgets changed from surplus to deficit. The sulphur deficit was further increased by reducing sulphur input. In the course of the drought/rewetting experiment, a distinct increase of nitrate budgets was found. A possible nitrification or an acidification pulse was not observed.

Fluorescence Decay of Natural Organic Matter (NOM)—Influence of Fractionation, Oxidation, and Metal Ion Complexation

Time-resolved fluorescence measurements of aquatic natural organic matter (NOM) derived from different origins were performed using the time-correlated single-photon counting technique. The obtained experimental data were analyzed with nonlinear least-squares (NLLS) algorithms. The results of a global analysis with three exponential decay terms were compared with the results obtained in a distribution analysis (exponential series method; ESM). Fulvic acid fractions from a bog lake water, from a brown coal production effluent, and from a soil seepage water as well as NOM from a municipal waste water were investigated. The influence of the emission wavelength on the NOM fluorescence decay was monitored. Furthermore, the influence of fractionation using size exclusion chromatography, of ozonation, and of metal ion complexation on the fluorescence decay of the NOM samples was investigated.

The effects of limestone and of limestone plus NPK fertilization on the soil and mass balance of a spruce stand ( Picea abies (L.) Karst.) in the Vosges mountains

Calcareous amendment and/or fertilization trials were carried out in a declining 66-year-old Norway spruce ( Picea abies (L.) Karst.) stand in the Vosges mountains (northeast France, altitude 1100 m) in 1985. The aim was to test tree response to nutritional deficiencies (Ca + Mg) and to alleviate soil acidity. In 1988, experimental equipment was set up to collect atmospheric input (bulk precipitation, throughfall) and soil seepage water. The soils are podzolic (‘ocre-podzolique’), derived from an acid-poor granitic bedrock (‘granite du Valtin’). The soils are coarsely textured, hence very porous. They are very acid (pH 3.4 in the A 1 horizon, and pH 4.1 in the Bs horizon). The cation exchange capacity (CEC) is highly saturated in exchangeable acidity: 86% in the A 1 horizon. Ca 2+ + Mg 2+ saturation is very low (<10% in A 1 and <1% in the subsoil). Liming and fertilization significantly increase soil pH, base cation saturation and decrease soil acidity, especially in the surface horizons. Bulk precipitation is dilute and acidic (pH 4.5); ion concentration of the precipitation greatly increases after passing through the tree canopy. Dry deposition is moderate and has values in the lower range reported for Europe. Nitrification produced large amounts of NO 3 −-N and H + ions in the O layer and organo-mineral horizons. Nitrate and aluminium dominate the chemical composition of the soil see-page water. Liming induces a considerable rise in the soil solution pH and the base cations (Ca 2+ + Mg 2+) and decreases nitrate and aluminium substantially. Liming alone seems to lower the rate of nitrification. Addition of fertilizers increases the deep drainage of base cations which could reduce the long term efficiency of liming. Improvement of tree health-status accords with the positive effects of liming and/or fertilization on the soil's solid phase and solution.

Wechselwirkung von Grundluft und Sickerwasser in carbonatischen Schottern der Münchener Schotterebene

Wechselwirkung von Grundluft und Sickerwasser in carbonatischen Schottern der Münchener Schotterebene