Bog Water Research Articles

Geochemical Mixing in Peatland Waters: The Role of Organic Acids

The close interplay between hydraulic and biotic processes controls the evolution of ecosystems in large, circumboreal peatlands and the degree to which they lose, gain or sequester carbon. In peatlands, biota significantly alters surficial acid–base equilibrium and solute chemistry by releasing dissolved organic compounds into surface and pore waters, which then mix through advection and dispersion through pore water flow paths. We report herein the results of new geochemical mixing models that incorporates organic acid dissociation constants to understand how organic acids control the acid–base chemistry in mixtures of dilute acidic bog pore waters and circum-neutral groundwater (typical of carbonate terrains) that upwells or disperses into peat deposits. In our new mixing models, at least twice as much groundwater is required to neutralize bog water acidity when dissolved organic carbon concentrations exceed 10 mmol/L than in their absence. Although it remains uncertain how future climatic change will alter the composition of dissolved organic matter in peatlands, organic acids should remain an important factor with respect to potential neutralization of peatland waters by groundwater sources. The acid base equilibria in large peat basins not only has important implications for vegetation patterning but also for biogeochemical cycles in these globally important reservoirs for carbon.

Drainage Impact on Plant Cover and Hydrology of Aukštumala Raised Bog (Western Lithuania)

Abstract One-third of the former Aukstumala raised bog (western Lithuania) has been preserved as Telmological Reserve since 1995, while the remaining territory is still under active industrial peat mining or are abandoned peat harvesting fields. The present study was carried out in 2013 and aimed to assess long-term human impact on the structure of plant cover and hydrology of Aukstumala raised bog. On the basis of vegetation assessment (Twinspan analysis), four habitat types were identified: i) active raised bog, ii) degraded raised bog drained by ditches, iii) contact zone of the bog and the peat mining fields and iv) recently burnt areas. The largest anthropogenic impact on vegetation cover was found in the degraded raised bog drained by the ditches and in the burnt area, where the proportion of plant species atypical to ombrotrophic raised bogs was the highest. Water electrical conductivity negatively correlated (r = -0.57) with bog water level, whereas correlation between pH and bog water level was weaker (r = -0.38). Water level in the active raised bog was significantly higher than in the rest three habitat types. Electrical conductivity values in the active raised bog were significantly lower compared to the degraded raised bog and burned area habitats. In order to recreate favourable conditions for peat accumulation and natural functioning of bog ecosystem, mean bog water level should be raised at least up to -32 cm (the optimum water level assigned for most of the typical ombrotrophic species fell into the range of -20 - -32 cm).

Spatial-Temporal Regularities in Changing Chemical Composition of Bog Waters in Taiga Zone of Western Siberia

The generalization of data on bog water chemistry has been performed in taiga zone of Western Siberia within 1998–2011. It is shown that the decrease in dissolved salt concentrations over the territories included in the row «eutrophic swamp – mesotrophic swamp – oligotrophic bog» is observed in the course of deterioration of water-mineral supply for bog plants, in the cross-section of peat formation – from inert layer to the upper part of active layer. It is stated that during a year there are maximums in trace element contents, biogenic matter, organic acids in spring and most of principle ions – in summer.

Distribution of inorganic pollutants over the depth of upper peat deposit

A model of distribution of inorganic substances in the polluted waters of an oligotrophic bog has been developed and geomigratory calculations have been carried out on the example of Vasyugan Bog. It is shown that the most significant changes of mineralization of bog waters caused by the inflow of industrial waste waters from oil and gas production enterprises are referred to the high layer with a thickness of approximately 0.5–1.0 m. The creation of loam as an insulating barrier in the active layer of the bog helps reduce the negative impact on the waters, but does not preserve their baseline state on the lower layer.

Elemental composition and structural peculiarities of humic acids in bog waters of taiga zone

Results of a complex studying the preparations of humic acids from bog waters by methods of IR spectroscopy, nuclear magnetic resonance and electronic paramagnetic resonance have been considered in the paper. Properties of humic acids are evaluated according to the elemental composition. Commonality and character of varying the composition of humic acids under forest oligotrophic and mesotrophic bogs are discussed hereaswell. The opinion about probable mechanisms of humic acid synthesis in bogs of different genesis is suggested.

Short-term effects of phosphorus addition and pH rise on bacterial utilization and biodegradation of dissolved organic carbon (DOC) from boreal mires

Natural mires and forested peatlands are known to be very significant sources of dissolved organic carbon (DOC) to aquatic ecosystems. Peatland management operations (e.g., forestry operations, restoration of drained mires and peat mining) and extreme hydrological events may increase the DOC runoff. We hypothesized that an increase in phosphorus (P) leaching, together with near-neutral conditions in recipient lakes will accelerate decomposition of DOC that originates from acidic, nutrient-poor mire waters. The efficiency of DOC utilization was evaluated by measuring microbial respiration and bacterial production (BP) in short-term laboratory experiments with runoff waters from six boreal mire sites. Mere inorganic phosphorus (PO4-P) addition did not affect the rate of respiration or the proportion of decayed DOC. However, in the nutrient-poor bog waters, P addition slightly promoted BP and bacterial growth efficiency (BGE). In contrast, the elevation of pH alone, and the elevation of pH and PO4-P level together, caused a significant increase in respiration and in the proportion of decayed DOC, but did not affect net BP. Elevated pH alone, however, depressed BGE when compared to that under the combined elevation of pH and PO4-P. These results suggest that the increased P availability, e.g., after mire restoration, would slightly benefit bacterial net growth in P-limited waters. However, in near-neutral recipient lakes, the increased microbial decomposition of mire-originated DOC contributes more to carbon dioxide (CO2) supersaturation than potentially supporting detritus-based food chains.

Natural post-fire bog recovery

The dynamics of natural recovery of bog massifs in Tver oblast, which suffered from fire in 2010, is discussed. The presented conclusions are based on three-year field observations at check sites of Galitskii mokh bog along with monitored variations of the physicochemical properties of peat ash and pyrolyzed peat, bog water chemistry, the development of microbial communities, and vegetation recovery. Moreover, some features of bog massif flooding are discussed.

Geochemistry of Iron in Organogenic Water of Western Siberia, Russia

In the central part of Western Siberia a study of the chemical composition of bog water was conducted. Bog water contains high concentrations of iron and organic matter. By means of thermodynamic methods were calculate the equilibrium of bog water with the major minerals. It was shown, that bog water is in equilibrium with kaolinite, vivianite, α-apatite. Primary aluminium minerals are undersaturated and release iron and other elements, to which a bog water are not at equilibrium and which is dissolve actively.

Study of Aqueous Chemical Forms of Silicon in Organic-rich Waters

The study of silicon species in organic-rich waters is a very significant problem. This type of waters is widely spread all over the world. It is characterized by a high content of humic substances, high color of water and low pH. In this regard, a certain determination of silicon concentration in this type of waters is impossible without a preliminary investigation of silicon species. The aim of this research is therefore an investigation of the ratio of silicon dissolved forms in organic-rich waters depending on the silicon concentration and the acidity of the water. The study of pH influence on silicic acids and a silicon–humic matter interaction was carried out using model solutions and natural bog waters (Tomsk region). It has been found that the degree of polymerization of silicic acids essentially depends on the acidity of a solution. Scanning of spectrophotometric measurements has shown that silicon does not form stable complexes with fulvic and humic acids in weak-acid media (рН 3-4). Studying the bog waters of Tomsk Region has shown that they (рН=3.66-3.80) contain only monomeric-dimeric and polymeric forms of silicic acids.

Birch encroachment affects the base cation chemistry in a restored bog

ABSTRACTIn this study, we compared non‐forested and forested habitat types of a degraded bog in Western Germany with regard to the base cation chemistry of their pore waters. Peat profiles were sampled in 10‐cm intervals every month from April to July 2009 down to a maximal depth of 150 cm. Pore waters were analysed for Ca, Mg, K and Na concentrations. Additionally, electrical conductivity and pH were measured in surface pools. Both habitat types were sampled with four replicate plots, showing the same vegetation structure.Strong differences were found between the concentrations and distributions of base cations in the pore water profiles from the different habitat types. The forested sites revealed higher concentrations for all base cations, but especially for Ca and Mg. Seasonality had an effect on element distributions in pore waters, but its influence was particularly strong at the forested sites. Element distributions and seasonality were caused by several interacting biological and physicochemical processes, such as plant uptake and mineralization or evaporative enrichment and dilution by rainwater. Concludingly, we draw implications for bog restoration and for the use of element ratios as criterion of mineral influence on bog waters. Our study clearly demonstrates the enhancement of base cation supply by birch encroachment, which is posing an additional burden on successful bog restoration. Additionally, the importance of an intact buffer zone around restored peat bogs is underlined. Copyright © 2013 John Wiley & Sons, Ltd.

Simulation of the hydrogeologic effects of oil-shale mining on the neighbouring wetland water balance: case study in north-eastern Estonia

The water balance of wetlands plays an integral role in their function. Developments adjacent to wetlands can affect their water balance through impacts on groundwater flow and increased discharge in the area, and they can cause lowering of the wetland water table. A 430 km2 area was selected for groundwater modelling to asses the effect of underground mining on the water balance of wetlands in north-eastern Estonia. A nature conservation area (encompassing Selisoo bog) is within 3 km of an underground oil-shale mine. Two future mining scenarios with different areal extents of mining were modeled and compared to the present situation. Results show that the vertical hydraulic conductivity of the subsurface is of critical importance to potential wetland dewatering as a result of mining. Significant impact on the Selisoo bog water balance will be caused by the approaching mine but there will be only minor additional impacts from mining directly below the bog. The major impact will arise before that stage, when the underground mine extension reaches the border of the nature conservation area; since the restriction of activities in this area relates to the ground surface, the conservation area’s border is not sufficiently protective in relation to underground development.

Habitat conditions and diversity of flora based on transitional peat bog in Bledow on the Silesian Upland

Presented research focused on determining the characteristics of soils, waters and vegetation covering a transitional peat bog in Bledow and potential hazards which might cause its degradation. Four soil pits were made for this purpose and piezometers were installed in their immediate vicinity. It allowed investigation of physical and chemical properties of this habitat waters. Diversity of the peat bog vegetation was determined on the basis of 17 phytosociological releves made by Braun-Blanquet’s method. The results demonstrated that the analysed peat bog is at the accumulation phase and the main factor shaping the habitat conditions in the peat bog itself and on its edge was high groundwater level. On the other hand, the feeding water and its level affected chemical and physical properties of the analysed peat bog soils. Low value of the studied peat bog water mineralisation and low share of calcium and magnesium ions in the mineralisation influenced low pH values and low degree of base cation saturation, which has been reflected in the floristic composition of the peat bog. In conditions of high moisture content, a process of organic matter accumulation was taking place in the surface horizons, whereas on the peat bog and on its edge an apparent soil and vegetation zonation was visible. On the edge of the peat bog trees encroaching into Sphagno recurvi-Eriophoretum angustifolii peat bog patches was observed on semi-hydrogenic soils and disappearance of species of the Scheuchzerio-Caricetea nigrae class. It was found that disturbance of natural water relationships poses the most serious potential hazard to the analysed peat bog.

Many-year Fluctuations of River Runoff in South-taiga Subzone of the Western Siberia

A detailed analysis of river flow long-term changes in the Southern taiga subzone of Western Siberia has been carried out with the Chaya River basin as an example. Causal statistical analysis of changes in groundwater levels, bog water level, air temperature and atmospheric precipitation has been performed. The conducted studies revealed a statistically significant trend in the increase of surface runoff in the winter low flow of the Chaya River and its large tributaries (the Iksa and the Parbig), as well as the underground runoff component for virtually the entire year. An ambiguous regularity has been observed in the change of the level regime of rivers. The main reason for the observed changes in the water regime of the said territory is the redistribution of atmospheric moisture and shifting of the boundaries of hydrological seasons.

Hydrochemical and microbiological characteristics of bog ecosystems on the isthmus of Svyatoi Nos Peninsula (Lake Baikal)

Presented are the results from hydrochemical and microbiological investigations into Arangatui bog ecosystems on the isthmus of Svyatoi Nos Peninsula on the shores of Lake Baikal. The formation features of bog waters as a result of a rise in the lake’s water level.

FERRUGINATED AND LEACHED LAPILLI TUFF AND TUFF IN THE VERBRANDE BERG FORMATION, ECCA GROUP, HUAB BASIN, NAMIBIA

Burnt Mountain is the name attached to a series of low, dark-coloured hills, dominantly composed of carbonaceous shale, siltstone, sandstone and various ferruginous rocks belonging to the Permian Verbrande Berg Formation, Ecca Group, Karoo Supergroup, in the Huab Basin, northwestern Namibia. At this site, which owes its name to the “burnt” appearance of the rocks, the Ecca Group rocks form a 150 m high mesa, capped with aeolian sandstone of the Cretaceous Twyfelfontein Formation, Etendeka Group. Reinvestigation of the outcrops at Burnt Mountain revealed that the exceptional 600 m-wide outcrop of the Verbrande Berg Formation at this site is the result of a north-south normal fault with a downthrow to the west. This fault forms one of a series of comparable north-south-striking structures in the Huab Basin that are linked to the opening of the proto-Atlantic Ocean. In the lower part of the Verbrande Berg Formation, where the carbonaceous shale is enriched in carbon, lenses of ferruginous fossiliferous carbonate rocks (FFC) with abundant plant fossils, as well as large (m-sized), flattened, ferruginous concretions are developed. Small concretions (cm-sized) as well as bedding-parallel segregations of ferric oxyhydrate minerals (largely hematite and goethite) are common in the FFC and are interpreted to be sulphide-derived. In the middle part of the Verbrande Berg Formation, a prominent unit (PU) of a medium-bedded, micro-crystalline, ferruginous and porous rock (FPR) is interbedded with the carbonaceous shale and sandstone. The FPR, which contains altered relicts of glass particles and possibly accretionary lapilli spheres, is interpreted to be the leached and ferruginated product of coarse-grained vitric lithic lapilli tuff and tuff, emplaced on an active swamp surface. The associated volcanic activity apparently was long-lived and culminated in the deposition of the PU. The ferrugination of the FPR is attributed to interaction of the nascent volcaniclastic rocks with acid bog water, augmented by oxidation products of early diagenetic sulphide that formed in the FPR on burial. Prolific development in places of Liesegang structures in the FPR is ascribed to fault-related fracturing and the infiltration of oxygenated meteoric water, prior to the intrusion of dolerite dykes that are here tentatively associated with the Etendeka volcanism. The positive identification of volcaniclastic rocks in the Verbrande Berg Formation in the Huab Basin corresponds to the occurrence of tuffs, at the same stratigraphic level, in comparable rocks in the Aranos Basin in southern Namibia as well as in the western parts of main Karoo Basin in South Africa. The FPR is the main source of the dark-coloured hematitic clasts (“clinker-like” rock) which contribute to the “burnt” appearance of the Burnt Mountain.

The influence of environmental factors on the CO2 emission from the surface of oligotrophic peat soils in West Siberia

The influence of various ecological factors (air and soil temperature, atmospheric pressure, level of peatland waters, and the content of CO2 in the atmosphere) on the emission of CO2 from the surface of a peat deposit of an oligotrophic peatland in the south taiga subzone of West Siberia was studied. On the basis of the investigations, day and seasonal dynamics of the emission of CO2 from the surface of the peat deposit were revealed. A detailed correlation analysis allowed us to describe the dependences of the CO2 flux from the surface of the peat deposit on the environmental parameters at various levels of averaging: hour, day, and month. It was shown that the temperature of the air and surface of the peat deposit have a reliable impact on the emission of CO2 on all time scales. The atmospheric pressure, as a factor that changes relatively slowly, influences the emission of CO2 weakly. The performed studies did not allow us to draw an unambiguous conclusion about the influence of the level of bog waters on the emission of CO2 from the surface of a peat deposit.

Variations in water regime of bogs in Northern and Northwestern Russia under the effect of climatic factors

The mechanism and factors of the impact of climate changes on the level regime of bog water and the runoff from bogs has been established.

The use of k-values to examine plant ‘species signals’ in a peat humification record from Newfoundland

Peat humification analysis has been used widely over the last three decades to reconstruct bog surface wetness (BSW) for use as a palaeoclimate proxy. The technique has the advantage that it is quick and relatively inexpensive to perform, allowing for high resolution and contiguous sampling of peat archives. However, some concerns have been raised over the quality of the resultant proxy-climate records because changes in the plant species composition of peat may contribute a ‘species signal’ to records, potentially confusing the relationship between bog water table position and the apparent degree of peat humification. This paper uses the k-values of fresh plant material (sensuOverbeck, 1947 – i.e. the absorption value of the alkali extracts of fresh plant material) to explore the impact of changing plant colouration in a Holocene peat humification-based palaeoclimate archive from Newfoundland. We calculate k-scores for peat samples, using plant macrofossil data and the k-values of individual species to provide a down-core visualisation of the plant species signal. Although, overall, the humification data are validated, comparison of the original humification data with a k-adjusted version shows that the species signal is sometimes sufficient to change the timing and number of decadal to centennial-scale events recorded in the data as well as millennial to multi-millennial-scale trends.

High nitrogen deposition alters the decomposition of bog plant litter and reduces carbon accumulation

AbstractBogs are globally important sinks of atmospheric carbon (C) due to the accumulation of partially decomposed litter that forms peat. Because bogs receive their nutrients from the atmosphere, the world‐wide increase of nitrogen (N) deposition is expected to affect litter decomposition and, ultimately, the rate of C accumulation. However, the mechanism of such biogeochemical alteration remains unclear and quantification of the effect of N addition on litter accumulation has yet to be done. Here, we show that 7 years of N addition to a bog decreased the C : N ratio, increased the bacterial biomass and stimulated the activity of hydrolytic and oxidative enzymes in surface peat. Furthermore, N addition modified nutrient limitation of microbes during litter decomposition so that phosphorus became a primary limiting nutrient. Alteration of N release from decomposing litter affected bog water chemistry and the competitive balance between peat‐forming mosses and vascular plants. We estimate that deposition of about 4 g N m−2 yr−1 will cause a mean annual reduction of fresh litter C accumulation of about 40 g m−2 primarily as a consequence of decreased litter production from peat‐forming mosses. Our findings show that N deposition interacts with both above and below ground components of biodiversity to threaten the ability of bogs to act as N‐sinks, which may offset the positive effects of N on C accumulation seen in other ecosystems.

Mössbauer studies of subfossil oak

Subfossil oak wood found in a dried-up bog in Bavaria, Germany, was studied by Mossbauer spectroscopy. The bog oaks contain substantial amounts of iron taken up from the bog waters and presumably forming complexes with the tanning agents in the oak wood. The iron is mainly Fe3 + and much of this exhibits an uncommonly large quadrupole splitting of up to 1.6 mm/s that can tentatively be explained by the formation of oxo-bridged iron dimers. Only rarely, mainly in the dense wood of the roots of bog oaks, was divalent iron found. When the wood was ground to a powder the divalent iron oxidized to Fe3 + within hours. This suggests that iron is taken up from the bog water as Fe2 + and oxidizes only when the wood emerges from the water and comes into contact with air.