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Peatlands store carbon in the form of dead organic residues. Climate change and human impact impose risks on the sustainability of the peatlands carbon balance due to increased peat decomposition. Here, we investigated molecular changes in the upper peat layers (0-40 cm), inferred from high-resolution vertical depth profiles, from a boreal peatland using two-dimensional H-1-C-13 nuclear magnetic resonance (NMR) spectroscopy, and comparison to delta C-13, delta N-15, and carbon and nitrogen content. Effects of hydrological conditions were investigated at respective sites: natural moist, drainage ditch, and natural dry. The molecular characterization revealed preferential degradation of specific side-chain linkages of xylan-type hemicelluloses within 0-14 cm at all sites, indicating organic matter losses up to 25%. In contrast, the xylan backbone, galactomannan-type hemicelluloses, and cellulose were more resistant to degradation and accumulated at the natural moist and drainage site. delta C-13, delta N-15, and carbon and nitrogen content did not correlate with specific hemicellulose structures but reflected changes in total carbohydrates. Our analysis provides novel insights into peat carbohydrate decomposition and indicates substantial organic matter losses in the acrotelm due to the degradation of specific hemicellulose structures. This suggests that variations in hemicellulose content and structure influence peat stability, which may have important implications with respect to climate change.

Oligotrophic peatlands traditionally have a high profile in microbiological research. Eutrophic peatlands are studied by residual principle and their research is generally focused on the active layer, acrotelm. The purpose of our study was to assess microbial biomass, its structure and activity in the full profiles of peatlands of various geneses. We investigated eutrophic peatlands of lacustrine, forest, and floodplain origins in Tver and Tomsk regions. Luminescent microscopy was used to analyze the microbial biomass. Microbial respiration was examined by gas chromatography. Microbial biomass stocks calculated for a three-meter layer of the studied peatlands varied from 7 to 13 t/ha. Eukaryotic biomass stocks reached 3–9 t/ha, and prokaryotic biomass stocks were about 3–4 t/ha. Eukaryotes predominated in the microbial biomass of the acrotelm, while prokaryotes predominated in the microbial biomass of the catotelm. Bacteria dominated in the structure of prokaryotic biomass all over the profiles of the studied peatlands. The fraction of actinomycetic mycelium did not exceed 15%. It was found that prokaryotic biomass depends on the botanical composition of peat in the eutrophic peatlands. This dependence becomes stronger from the woody peat to the herbaceous peat. The comparison of eutrophic peatlands of different geneses demonstrated their microbial specificity. Thus, the peatland of forest bogging had the maximum microbial pool among all peatlands. The peatland of lacustrine origin was characterized by the saturation of the acrotelm with microbial biomass. The peatland of floodplain origin was maximally enriched in bacterial biomass. In many layers of studied peatlands, the potential respiration level was 2–5 times higher than the actual one. Microbial respiration reached its maximum intensity in the peatland of floodplain origin.

This article contains an analysis of structural and functional parameters of bacterial complexes taken for examination from complete profiles of fens assigned to the Klyukvennoe and Karbyshevskoe wetlands in Tomsk oblast. Bacteria in the fens are revealed throughout the entire profile. Their number determined by a direct method of fluorescence microscopy is high and varies from 27 to 78 × 109 cells/g of dry peat. The high number of saprotrophic bacteria (to 108–109 CFU/g of dry peat) is detected by the plate method. An increase in the number of saprotrophic bacteria down the fen profile is revealed. These data enable us to conclude for the first time that index k (a dimensionless universal characteristic of natural prokaryotic communities) in fen profiles decreases with depth. The bacterial cultures isolated from the fens studied are assigned to ten taxa: Bacillus, Streptomyces, Arthrobacter, Microbacterium, Pseudomonas, Flavobacterium, Dyadobacter, Janthinobacterium, Pedobacter, and Myxobacteriales. The acrotelm is dominated by bacterial cultures represented by genera Bacillus and Streptomyces; and Pseudomonas, Dyadobacter, and Arthrobacter are the dominants of the catotelm. The functions of bacterial genera and species identified by molecular biological methods are described. The study of nitrogen fixation, denitrification, and methanogenesis has shown that bacteria are viable and active throughout the entire peat profile.

Peatlands have been important terrestrial carbon (C) reservoirs throughout the Holocene, yet whether these ecosystems will become stronger or weaker C sinks in the future remains debated. While surface peat layers (acrotelm) have a greater apparent rate of C accumulation than deeper, millennial-aged peat (catotelm), it is difficult to project how much more aerobic decomposition will take place before the younger surface cohorts join the older deeper ones. Studies have suggested that warming could lead to weakened C accumulation in peatlands due to enhanced aerobic decay in the acrotelm, which would lead to a slower transfer of peat into the catotelm, if any. Conversely, other studies have suggested increased C accumulation in the acrotelm and thus, larger long-term C transfer into the catotelm under warming conditions because of greater plant productivity and faster peat accumulation. Improving our predictions about the rate of present and future peatland development is important to forecast feedbacks on the global C cycle and help inform land management decisions. In this study, we analyzed two peat cores from southern Patagonia to calculate their long- versus short-peat C accumulation rates. The acrotelm rates were compared to the catotelm peat C legacies using an empirical modeling approach that allows calculating the future catotelm peat storage based on today's acrotelm characteristics, and thus predict if those recent rates of C accumulation will lead to greater or weaker long-term C storage in the future. Our results indicate that, depending on local bioclimatic parameters, some peatlands may become stronger C sinks in the future, while others may become weaker. In the case of this study, the wetter site is expected to increase its C sink capacity, while our prediction for the drier site is a net decrease in C sequestration in the coming decades to centuries.

Floral Lagerstätten deposits (i.e., fossil sites with exceptional preservation and diversity) are preserved within the Miocene brown coals of the Latrobe Group, Gippsland Basin, Australia. Three independent mechanisms are conducive to their accumulation. Throughout the coal seams the conversion of plant material into charcoal (fusain) and its accumulation in a subaqueous setting provides one means of near-perfect preservation. A second and more uncommon example occurs in the form of a 20 cm thick leaf-litter horizon that extends for over two kilometers. In this case, flooding of freshwater tributaries and lakes during the early stages of low-gradient peat development resulted in an extensive, shallow, acidic and water-filled depression that subsequently accumulated and preserved the surrounding plant material. The third and most common form results from the deposition of plant material into small, isolated pools that formed as depressions on the ombrogenous (i.e., rain-fed) and domed surface of the peatlands. In all of these settings an essential component allowing detailed floral preservation is the delivery of plant material directly to the anaerobic catotelm (i.e., below the water table), hence avoiding the physical and chemical processes of degradation that typically occur in the surficial aerobic acrotelm (i.e., above the water table). Leaf litter that falls into low-energy acidic and anoxic water-filled depressions that lie below the acrotelm will likely be well-preserved.

Rising temperatures have the potential to directly affect carbon cycling in peatlands by enhancing organic matter (OM) decomposition, contributing to the release of CO2 and CH4 to the atmosphere. In turn, increasing atmospheric CO2 concentration may stimulate photosynthesis, potentially increasing plant litter inputs belowground and transferring carbon from the atmosphere into terrestrial ecosystems. Key questions remain about the magnitude and rate of these interacting and opposing environmental change drivers. Here, we assess the incorporation and degradation of plant- and microbe-derived OM in an ombrotrophic peatland after 4 years of whole-ecosystem warming (+0, +2.25, +4.5, +6.75 and +9 degrees C) and two years of elevated CO2 manipulation (500 ppm above ambient). We show that OM molecular composition was substantially altered in the aerobic acrotelm, highlighting the sensitivity of acrotelm carbon to rising temperatures and atmospheric CO2 concentration. While warming accelerated OM decomposition under ambient CO2, new carbon incorporation into peat increased in warming x elevated CO2 treatments for both plant- and microbe-derived OM. Using the isotopic signature of the applied CO2 enrichment as a label for recently photosynthesized OM, our data demonstrate that new plant inputs have been rapidly incorporated into peat carbon. Our results suggest that under current hydrological conditions, rising temperatures and atmospheric CO2 levels will likely offset each other in boreal peatlands., Global Change Biology, 28 (3), ISSN:1354-1013, ISSN:1365-2486

Spatial surface patterns of hummocks, hollows, ridges, and pools (microtopography) are common features of many northern peatlands and are particularly distinct within the vast peatlands of the Hudson Bay Lowland (HBL), Canada. Hypotheses and models describe how small-scale feedbacks among vegetation, hydrology, and nutrients cause spatial differences in peat accumulation that enable microforms and surface patterns to develop over time. Empirical tests of the predictions from theoretical models of these proposed feedback mechanisms are limited, particularly in large peatland complexes such as the HBL. We investigate feedbacks controlling peatland structure and function in an ombrogenous bog and a minerogenous fen in the HBL. Our sites represent surface patterns found in many northern peatlands, specifically spatially irregular hummocks and hollows, and parallel ridges and pools that are perpendicular to slope. We found the occurrence of different spatial patterns depends on position within a peat landform, with these differences attributed to the ecohydrological setting. In turn, the ecohydrological setting, with different water table depths, nutrient availability, and species composition, influences the strength and direction of feedback mechanisms at the microform scale. Our data support the prediction of a positive feedback between plant productivity and acrotelm thickness for peat accumulation and hummock growth and that this may be enhanced by water ponding on slopes to form ridge–pool tracks. We did not find evidence to support the proposed feedback among evapotranspiration-driven transport of water and nutrients for the development of hummocks. Our results suggest a combination of mechanisms operating at various temporal and spatial scales is associated with the development of surface patterns in northern peatlands.

In recent decades, a severe wildfire situation threatening the territory along the periphery of the Bastak State Nature Reserve (Russia) has developed in the Petrovskaya Pad'. In this paper, we assessed the current state of the vegetation cover and post-pyrogenic changes in the Petrovskaya Pad', based on the geobotanical survey during a joint expedition in 2009. At present, this area of the Middle Amur Lowland is a vivid example of wetland degradation due to the repeated wildfire impact initiated by the local people and agricultural workers in the Amur region. The widespread xerophytisation process of fen vegetation, due to a sharp drop in the groundwater level, was observed. A comparison with the data of previous studies led to the conclusions that now mesotrophic shrub-Sphagnum bogs, described earlier, have completely disappeared from the vegetation cover of the territory. We suggest that their degradation is caused by the continuously acting pyrogenic factor. In addition, the paper for the first time provides data on the dynamics of the acrotelm structure in the post-pyrogenic period, which were obtained during a nine-year monitoring. The profound changes in the acrotelm structure are responsible for the restoration of mesotrophic bogs taking decades.

Ombrotrophic raised bogs in the forest-steppe zone of Western Siberia are at the extreme southern limit of their distribution and exist under conditions of insuffcient moisture and are surrounded by saline soils. In the changing climate, it is especially important to carry out regime observations of various components of such ecosystems. The aim of this research was to reveal peculiarities of temperature regime of fbrist histosol at a pine - dwarf shrub - Sphagnum raised bog in the Baraba forest-steppe of Western Siberia. We carried out the study at a pine - dwarf shrub - Sphagnum raised bog, Nikolaevsky ryam (55°08'59''N, 79°02'59''E ). An autonomous soil temperature measurement system (IMCES SB RAS, Tomsk) was used. Temperature was registered at depths of 2, 5, 10, 15, 20, 30, 40, 60, 80, 120, 160, 240 and 320 cm once per hour, the duration of the study was 4.5 years (05.10.2012-22.05.2017). We used data of Barabinsk meteorological station on air temperature, precipitations and snow cover depth ( See Table 1 ). Average annual temperature of the fbrist histosol in 2-20 cm layer was 4.7-5.1°C and it decreased at a depth of 240 cm to 3.3-3.7°C. The highest average monthly temperatures of the upper peat layer were 18.4-20.2°C in summer months, and the lowest ones were -2.0...-5.1°C and were recorded from November to February. Simultaneously, monthly air temperatures were -15...-26°C ( See Fig. 1 ). Average daily temperatures of the peat deposit were always minimal in November, reaching -11...-17°C due to the low thickness of thermal insulating snow cover. The annual soil temperature amplitude in the upper 20 cm ranged from 19 to 23°C in different years, and it did not change over the years below 40 cm and decreased from 12°C at a depth of 60 cm to 3°C at a depth of 240 cm ( See Fig. 2 ). Soil temperatures were always positive below 60 cm. The sum of positive average daily temperatures in the surface layer of the bog ranged from 2200 to 2400°C, at a depth of 20 cm it decreased by 200°C, and at a depth of 2.4 m the sum of positive temperatures decreased by 1000°C in comparison with the surface layer. The sum of negative average daily temperatures was -1660 ... -2100°С in different years of observations ( See Fig. 3 ). The dynamics of changes in the sums of negative temperatures for air and for peat soil do not coincide due to the change in thickness and time of establishment of snow cover and the different water table depths that have a signifcant role in the temperature regime of the soil in winter. The ratio of the sums of positive and negative temperatures at a depth of 2 cm (under a layer of live Sphagnum mosses) and 20 cm to the corresponding sums of air temperatures characterizes the soil warm-accumulating ability. During several years, these indicators decreased for positive temperatures and increased for negative ones, indicating an increase in soil climate severity ( See Table 2 ). Temperature gradients are positive when the heat flux flows from the soil to the atmosphere, and the peat deposit cools down; and negative when the heat flows in the opposite direction and the soil is heated. We observed the maximum temperature gradients in the layer of 15–30 cm, it is the largest negative value typical of May when the soil is intensively warmed, and they gradually decrease during the summer ( See Fig. 4 ). Freezing of the soil took place in October-November; at this time the freezing depth reached 40 cm, and then slowly descended during the winter. High water table standing and warm weather in autumn 2013/14 caused a decrease in the depth of freezing to 20 cm at the beginning of winter. In the spring, the thawing of peat deposit began immediately after the snow had melted and for a few days covered the entire freeze layer ( See Fig. 5 ). The duration of the frostfree period in the moss carpet (at a 2 cm depth) varied from 132 to 170 days, while the number of days with positive average daily temperatures was more stable, 161±5 days ( See Table 3 ). During the observation period, average summer temperatures, the sum of average daily positive temperatures and the sums of negative average daily temperatures (absolute values) increased, as well as average winter temperatures decreased and the depth of freezing lowered. The weather conditions of November were crucial for soil temperature regime during the winter due to air temperature and time of onset of snow cover with 15 cm thickness or more as well as the water table depth in autumn. In comparison with the same soils of the southern taiga, fbrist histosols in the forest-steppe were distinguished by an enlargement in acrotelm thickness and an increase in continentality of soil climate, which were due to the deeper water table. This is expressed in higher average values of summer temperatures, a greater depth of attenuation of daily temperature fluctuation, a more substantial decrease in average annual temperatures with the depth, greater annual amplitude along the profle, greater depth of maximum temperature gradients, an earlier seasonal permafrost melting, as well as a longer duration of periods with negative temperatures and a greater depth of freezing. The paper contains 5 Figures, 3 Tables and 27 References.

International audience; Peatlands are habitats for a range of fragile flora and fauna species. Their eco-physicochemical characteristics make them as outstanding global carbon and water storage systems. These ecosystems occupy 3% of the worldwide emerged land surface but represent 30% of the global organic soil carbon and 10% of the global fresh water volumes. In such systems, carbon speciation depends to a large extent on specific redox conditions which are mainly governed by the depth of the water table. Hence, understanding their hydrological variability, that conditions both their ecological and biogeochemical functions, is crucial for their management, especially when anticipating their future evolution under climate change. This study illustrates how long-term monitoring of basic hydro-meteorological parameters combined with statistical modeling can be used as a tool to evaluate i) the horizontal (type of peat), ii) vertical (acrotelm/catotelm continuum) and iii) future hydrological variability. Using cross-correlations between meteorological data (precipitation, potential evapotranspiration) and water table depth (WTD), we primarily highlight the spatial heterogeneity of hydrological reactivity across the Sphagnum-dominated Frasne peatland (French Jura Mountain). Then, a multiple linear regression model allows performing hydrological projections until 2100, according to regionalized IPCC RCP4.5 and 8.5 scenarios. Although WTD remains stable during the first half of 21th century, seasonal trends beyond 2050 show lower WTD in winter and markedly greater WTD in summer. In particular, after 2050, more frequent droughts in summer and autumn should occur, increasing WTD. These projections are completed with risk evaluations for peatland droughts until 2100 that appear to be increasing especially for transition seasons, i.e. May–June and September–October. Comparing these trends with previous evaluations of phenol concentrations in water throughout the vegetative period, considered as a proxy of plant functioning intensity, highlights that these hydrological modifications during transitional seasons could be a great ecological perturbation, especially by affecting Sphagnum metabolism.

Peatlands contain a large portion of Earth's terrestrial soil organic matter in part due to a reduction in decomposition rates. Organic matter decomposition is initially mediated by extracellular enzyme activity, which is in turn controlled by temperature, moisture, and substrate availability; and all are subject to seasonal variation. As depth increases in peatlands, temperature variability and labile carbon inputs decrease. We hypothesized that the more stable recalcitrant subsurface would contain a smaller less diverse enzyme pool, that is better adapted to a narrow temperature range. Thus temperature dependence would be diminished at depth compared to superficial peat. Potential enzyme activity rates were determined across seasons and with depth in peat samples collected from the Marcell Experimental Forest in northern Minnesota, USA. The temperature dependence, assessed by activation energy, was quantified for three hydrolytic enzymes involved in nutrient cycling at up to 15 temperature points ranging from 2 °C to 65 °C. Potential enzyme activity decreased with peat depth as expected and corresponded with changes in peat composition and microbial biomass from the acrotelm to the catotelm. In an environmentally relevant temperature range (2–23 °C), activation energy decreased with depth for β-glucosidase as predicted and leucine amino peptidase activation energy was the lowest of all enzymes. Stable temperatures at depth appear to result in a microbial community containing enzymes that have lower sensitivity to temperature increases. Surprisingly, there was no significant seasonal effect on enzyme temperature dependence observed in our study. Based on these results, and without shifts in microbial community composition, warming of peat could result in increased carbon and phosphorus cycling at the surface but little change at depth. Additionally differences in enzyme temperature sensitivity suggest nitrogen cycling could remain constant with warming, potentially resulting in proteolytic nitrogen cycling being decoupled from carbon and phosphorus cycling.

In ombrotrophic peatlands, the moisture content of the acrotelm (vadoze zone) controls oxygen diffusion rates, redox state, and the turnover of organic matter. Thus, variably saturated flow processes determine whether peatlands act as sinks or sources of atmospheric carbon, and modelling these processes is crucial to assess effects of changed environmental conditions on the future development of these ecosystems. We show that the Richards equation can be used to accurately describe the moisture dynamics under evaporative conditions in variably saturated peat soil, encompassing the transition from the topmost living moss layer to the decomposed peat as part of the vadose zone. Soil hydraulic properties (SHP) were identified by inverse simulation of evaporation experiments on samples from the entire acrotelm. To obtain consistent descriptions of the observations, the traditional van Genuchten–Mualem model was extended to account for non-capillary water storage and flow. We found that the SHP of the uppermost moss layer reflect a pore-size distribution (PSD) that combines three distinct pore systems of the Sphagnum moss. For deeper samples, acrotelm pedogenesis changes the shape of the SHP due to the collapse of inter-plant pores and an infill with smaller particles. This leads to gradually more homogeneous and bi-modal PSDs with increasing depth, which in turn can serve as a proxy for increasing state of pedogenesis in peatlands. From this, we derive a nomenclature and size classification for the pore spaces of Sphagnum mosses and define inter-, intra-, and inner-plant pore spaces, with effective pore diameters of > 300, 300–30, and 30–10 µm, respectively.

To predict future spatio-temporal patterns of climate change, we should fully understand the spatio-temporal patterns of climate change during the past millennium. But, we are not yet able to delineate the patterns because the qualities of the retrieved proxy records and the spatial coverage of those records are not adequate. Northern Xinjiang of China is one of such areas where the records are not adequate. Here, we present a 500-yr land-surface moisture sequence from Heiyangpo Peat (48.34°N, 87.18°E, 1353 m a.s.l) in the southern Altai Mountains within northern Xinjiang. Specifically, peat carbon isotope value of cellulose (δ13Ccellulose) was used to estimate the warm-season moisture variations and the degree of humification was used to constrain the δ13Ccellulose-based hydrological interpretation. The climatic attributions of the interpreted hydrological variations were based on the warm-season temperature reconstructed from Belukha ice core and the warm-season precipitation inferred from the reconstructed Atlantic Multidecadal Oscillations (AMO). The results show that humification decreased and the δ13Ccellulose-suggested moisture decreased from ~1510 to ~1775 AD, implying that a constant drying condition may have inhibited peat decay. Our comparison with reconstructed climatic parameters suggests that the moisture-level decline was most likely resulted from a constant decline of precipitation. The results also show that humification kept a stable level and the δ13Ccellulose-suggested moisture also decreased from ~1775 to ~2013 AD, implying that peat decay in the acrotelm primarily did not depend on the water availability or an aerobic environment. Again, our comparison with reconstructed climatic parameters suggests that the land-surface moisturelevel decline was most likely resulted from a steady warming of growing-season temperature.

International audience; Interpretations of the abundance and distribution of branched glycerol dialkyl glycerol tetraether (brGDGT) lipids have been increasingly applied to infer changes in paleoenvironment and to estimate terrigenous organic matter inputs into estuarine and marine sediments. However, only preliminary information is known regarding the ecology and physiology of the source organisms of these biomarkers. We assessed the production rates of brGDGTs under different redox conditions in peat, where these lipids are found in high concentrations, particularly at greater depths below the fluctuating water table. The incorporation of hydrogen relative to carbon into lipids observed in our dual stable isotope probing assay indicates that brGDGTs were produced by heterotrophic bacteria. Unexpectedly, incubations with stable isotope tracers of the surface horizon (5-20 cm) initiated under oxic conditions before turning suboxic and eventually anoxic exhibited up to one order of magnitude higher rates of brGDGT production (16-87 ng cm–3 y-1) relative to the deeper, anoxic zone (20- 35 cm; ca. 7 ng cm–3 y-1), and anoxic incubations of the surface horizon (< 3 ng cm–3 y-1). Turnover times of brGDGTs in the surface horizon ranged between 8 and 41 years in the incubations initiated under oxic conditions, in contrast to 123 to 742 years in anoxic incubations. As brGDGTs were actively produced during both anoxic incubations and those exposed to oxygen, we conclude that their source organisms are likely facultative aerobic heterotrophs that are particularly active in the peat acrotelm. Production rates of bacterial fatty acids (ca. 2 μg cm-3 y-1) were roughly two orders of magnitude higher than those of brGDGTs, suggesting that brGDGT producers are a minor constituent of the microbial community or that brGDGTs are a small component of the microbial cell membrane in comparison to fatty acids, despite the typically high brGDGT concentrations observed in peat. Multivariate analysis identified two branched fatty acids that shared a similar production pattern as brGDGTs among the experimental treatments and may be associated with brGDGT biosynthesis.

In ombrotrophic peatlands, the moisture content of the vadose zone (acrotelm) controls oxygen diffusion rates, redox state, and the turnover of organic matter. Whether peatlands act as sinks or sources of atmospheric carbon thus relies on variably saturated flow processes. The Richards equation is the standard model for water flow in soils, but it is not clear whether it can be applied to simulate water flow in live Sphagnum moss. Transient laboratory evaporation experiments were conducted to observe evaporative water fluxes in the acrotelm, containing living Sphagnum moss, and a deeper layer containing decomposed moss peat. The experimental data were evaluated by inverse modeling using the Richards equation as process model for variably-saturated flow. It was tested whether water fluxes and time series of measured pressure heads during evaporation could be simulated. The results showed that the measurements could be matched very well providing the hydraulic properties are represented by a suitable model. For this, a trimodal parametrization of the underlying pore-size distribution was necessary which reflects three distinct pore systems of the Sphagnum constituted by inter-, intra-, and inner-plant water. While the traditional van Genuchten-Mualem model led to great discrepancies, the physically more comprehensive Peters-Durner-Iden model which accounts for capillary and noncapillary flow, led to a more consistent description of the observations. We conclude that the Richards equation is a valid process description for variably saturated moisture fluxes over a wide pressure range in peatlands supporting the conceptualization of the live moss as part of the vadose zone.

Было проведено сравнительное исследование физических, химических и биохимических свойств акротелма (торфогенный горизонт) и катотелма (горизонт накопления торфа) участков с доминированием сфагновых и осоковых торфов в Западной Сибири. Концентрация общего азота прямо пропорциональна содержанию нитрат-ионов и ионов аммония, активности уреазы, объемной плотности, и обратно пропорционально отношению C/N, пористости и влажности в обоих рассматриваемых типах почв. Полученные результаты указывают на низкий уровень азотной трансформации и замедление процессов разложения органического вещества в сфагновых и осоковых типах почв. Исследование показало, что сфагновые торфа претерпевают значительные химические и биохимические трансформации (окисление, гидролиз, полимеризация) с аккумуляцией наиболее устойчивых соединений по сравнению с органическим веществом осоковых торфов.

The results of the study of the dynamics of a biomass and production of treeless grass-shrub-sphagnum bog communities formed on the reclaimed site 20 years after the drainage and undisturbed mesotrophic shrub-Sphagnum bog community (excluding tree layer) on the Middle Amur River lowlands are compared. This bog is in a subclimax state and functions in conditions of sharply fluctuating hydrological regime. Significant fluctuations in the bog water level caused by the uneven atmospheric precipitation are very typical for mires on the Middle Amur depression, both in growing seasons and from year to year. They have shown that a biomass structure changed and a productivity of sphagnum moss and herbaceous plants increased, while production of psychrophilic shrubs reduced during secondary swamping as a result of changes in the hydrological regime. Live biomass was 1106 g× m-2 on undisturbed bog and 1640 g× m-2 on the secondary swamped site. In above-ground part and acrotelm mortmass increased up to 3561 g× m-2 on the secondary bog compared to 2272 g× m-2 on undisturbed bog. NPP on the secondary swamped site varies between 627-863 g × m-2 per year. It is significantly higher than NPP of undisturbed phytocenosis which ranges from 538 to 662 g× m-2 per year. The dominant indigenous mires Chamaedaphne calyculata is respond to waterlogging and stabilizing the hydrological regime by increase in the mass of roots that provide the greatest contribution to production in comparison with its above-ground live phytomass. The ratio of above-ground and underground phytomass of herbaceous plants thus remains constant, despite the change of species in phytocenosis. The species composition of moss layer changes and significantly increases its productivity. In general, peat accumulation endogenesis accelerates. On mesotrophic bogs of the Middle Amur River lowland it is hampered by recurrent fires on a big time trend, causing them to function in subclimax phase.

Hydrological behavior of an ombrogenous raised peat bog has been observed and described in many studies; however, not in complexity with other soils. This research deals with the hydrological function of peat bog in a catchment where peat bog (formed by Histosol or other hydromorphic soils) covers only a part of the area (40–60%). Two soil types, creating two main hillslopes of the experimental catchment in this study, form the dominant soil types (Podzol and Histosol) in the Sumava Mountains, Czechia. A modified HBV model was used to estimate the contribution of each soil type to common outflow and for the estimation of the water balance. According to previous research and field observations, dominant hydrological processes were described for each hillslope (soil). The HBV model was used for the quantification of a ratio between fast and slow flow at Peat bog hillslope and Podzol hillslope. At Peat bog hillslope, the majority of outflow (67%) was formed from the upper soil layer (Acrotelm). In the mineral soil hillslope, a larger portion of runoff was generated from the lower soil layers or bedrock interface (61%). Peat bog contributes to a stream mainly during rainfall events; however, the model showed also significant deep percolation at the Peat bog hillslope and considerable contribution to baseflow during a year. Generally, more precipitation water was turned by the model into runoff at the Peat bog hillslope, which was also exhibited by a lower rate of actual evapotranspiration (21% of precipitation), compared to 29% in the case of Podzol hillslope. If we consider land-use changes in this locality in terms of expanding or reducing peat areas (draining, drains damming, droughts, etc.), this model could sufficiently estimate the hydrological behavior of local streams and thus can be potentially used in hydrological planning by local authorities.

Few guidelines exist for the effective revegetation of peatlands following the removal of in-situ oil and gas infrastructure. We conducted a manipulative field study in northeast Alberta, Canada, on a well pad undergoing removal and revegetation to test different management practices for facilitating vegetation establishment and recovery of a sphagnum-dominated peatland. A randomized block design was used to evaluate the effect of various revegetation practices, including augmenting natural recovery with the use of native transplants, acrotelm transfer from a similar intact donor peatland, and the use of variable surface microtopography. Although overall survival of transplants was similar between areas smoothed and left rough, areas that were rough had greater species richness under natural recovery, including trees, shrubs, and other perennial herbs. Moreover, survival and growth of woody transplants (Picea mariana—black spruce and Ledum groenlandicum—Labrador tea) were greater when planted within the top and middle microtopographic positions rather than micro-depressions. Survival of transplanted sedges (Carex spp.) was high at all topographic positions, but benefited the most in growth from planting in depressions. Contrary to expectations, no benefits of acrotelm application were found on vegetation recovery during the first two seasons, and even reduced the presence of some native vegetation. Although transplants directly contributed to revegetation, the recovering peatland remained highly dissimilar ( 90%) in composition relative to the neighboring peatland after two years.

Here we examine the arrangement of plant species across an oligotrophic bog/poor fen peatland complex in the North American boreal plain and the relationships of these species to their physical and chemical environment. A semi-uniform spatial sampling approach was utilized to describe the species assemblages, pore-water chemistry and physical condition of 100 plots throughout a single peatland complex. Regardless of sharing the same ground cover of Sphagnum mosses, the remaining species separated into four distinct assemblages, each with unique indicators. These species groups along with associated chemical and physical factors are organized into four ecosites: bog, margin (edge) and two poor fen ecosites. The plant assemblages of this peatland have a complex relationship with numerous gradients, both physical and chemical, including depth to water table, shade, pH, nutrient and base cation. Rather than being homogenous across the landscape, most environmental variables exhibit distinct spatial patterns and do so in relationship to the plant assemblages, forming spatially distinct ecosites across the complex. Base cation concentrations play a smaller role than previously thought in differentiating these ecosites, and in addition to shade and depth to water table, nitrogen in the form of dissolved organic nitrogen was highly related to the placement of these ecosites. Many significant chemical factors appear related to evaporative water loss within the peatland complex, and these chemical factors are used to differentiate the ecosites. However, the mediation of evaporative water loss is due largely to self-generated responses of the plant assemblages related to shade through plant morphology and peat acrotelm development related to depth to water table. We conclude that plant species and associated environmental gradients act together to form spatially distinct ecosites. The distribution of these ecosites within this large, environmentally complex peatland is largely controlled by differing self-generated responses along the hydrotopographical gradient of differential water loss.

Published data from different techniques used in the analysis of the main biomolecular families (lignin, carbohydrates and lipids) in 100 cm depth peat cores from the Sagnes peat bog (Limousin, France) were compared. Thermochemolysis using tetramethylammonium hydroxide was compared with the classical chemical degradation methods for lignin (CuO-NaOH oxidation) and carbohydrates (acid hydrolysis with HCl), and the Bligh and Dyer extraction method for lipids. Differences observed between the methods are mostly due to the different degradation mechanisms involved in each method. For lignin, the selective cleavage of β O 4 aryl ether bonds during thermochemolysis allowed identification of a more oxidized/degraded lignin pool in the deepest part of the peat core. For carbohydrates, the capacity of thermochemolysis to detect free (or terminal) carbohydrates showed an increase in microbial contribution at the interfaces between three distinct peat layers: the acrotelm, the upper part of the peat permanently above the water table; the mesotelm, the layer where water table fluctuations occur; and the catotelm, the bottom layer of peat that is permanently below the water table. For the lipid fraction, thermochemolysis revealed a lipid pool that was more influenced by microbial reworking. These results imply that, depending on the techniques used, the interpretation of the extent of degradation or source could differ. Therefore, TMAH thermochemolysis could be viewed and used as a complementary method of analysis, offering additional molecular data and contributing to a better understanding of the nature and sedimentation processes of organic matter in peat bogs.

Bogs can store large amounts of lead (Pb) and arsenic (As) from atmospheric deposition of anthropogenic emissions. Pb and As are exported along with dissolved organic carbon (DOC) from these organic-rich systems, but it is not yet clear which hydrological (pre)conditions favor their export. This study combines a 1-year monitoring of precipitation, bog water level and pore water concentration changes with bog discharge and DOC, iron, As and Pb stream concentrations. From these data, annual DOC, As, and Pb exports were calculated. Concentrations ranged from 5 to 30 mg L−1 for DOC, 0.2 to 1.9 μg L−1 for As, and 1.3 to 12 μg L−1 for Pb, with highest concentrations in late summer. As and Pb concentrations significantly correlated with DOC concentrations. Fluxes depended strongly on discharge, as 40 % of As and 43 % of Pb were exported during 10 % of the time with the highest discharge, pointing out the over-proportional contribution of short-time, high-discharge events to annual As, Pb and DOC export. Exponential increase in element export from the bog is explained by connection of additional DOC, As and Pb pools in the acrotelm during water table rise, which is most pronounced after drought. Pb, As and DOC concentrations in pore water provide evidence of an increase in the soluble Pb pool as soon as the peat layer becomes hydrologically connected, while DOC and As peak concentrations in runoff lag behind in comparison to Pb. Our data indicate a distinct bog-specific discharge threshold of 8 L s−1, which is thought to depend mainly on the bogs size and drainage conditions. Above this threshold, element concentrations do not further increase and discharge becomes diluted. Combining pore water and discharge data shows that As and Pb exports are dependent on not only the amount of precipitation and discharge but also on the frequency and depth of water table fluctuations. Comparing the annual bog As and Pb export with element inventories indicates that As is much more mobilized than Pb, with annual fluxes accounting for 0.85 and 0.27 ‰ of total As and Pb inventory, respectively.

Here we used organic composition and stable isotopic analysis to evaluate the effects of drainage and restoration at an ombrotrophic peatland, to assess whether rewetting of blanket bogs will reverse degradation. The organic composition of the peat and the isotopic fractionation between the solid (peat), liquid (pore water) and gas (soil gas) phases on actively accumulating, degrading and restored locations are compared. Fourier Transform Infrared Spectroscopy (FTIR) analysis of the organic material has shown a high level of humification (low decomposition) in the active peat. Stable isotope analysis in the solid, liquid and gas phases has corresponded with this and indicated that the active location is enriched in 13C in the solid and gas phases, 15N in the solid phase, 18O in the liquid and gas phases and D in the liquid phase, suggesting a closed system with limited isotopic fractionation and thus limited water movement and decomposition. The degrading location has a lower level of humification, and is depleted in 13C in the solid phase due to ingression of vascular plants. The restored location has high humification and enrichment of 13C and 15N in the solid phase, and D in the liquid phase suggesting increased microbial activity. 13C and 18O in the gas phase and 18O in the liquid phase are depleted, as a result of microbial mediated gas production and rewetting. FTIR analysis has also indicated a subsurface zone of increased decomposition between the acrotelm and catotelm in both the active and degrading peat. This is due to a stable water table and is not present within the restored location, which we attribute to water table fluctuation associated with rewetting. This zone of increased decomposition adds to the complexity of blanket bog peatlands and the assumption that all systems can be generalized under one conceptual model.

We applied principal component analysis on a data set of 55 compounds obtained with thermochemolysis with tetramethylammonium hydroxide as chemical agent from samples (24 different depths) along a one-meter length peat core. Principal component analysis allows to reduce the dimensionality of a data set that retains most of the variation present in the original variables (here F 1 + F 2 = 54.57%). Compounds are from four biochemical classes (lignin, carbohydrates and fatty and ω-hydroxy acids). Results show that samples are grouped in three clusters in the F1–F2 plot. Biomarkers of microbial and especially bacterial activity (terminally branched fatty acids) and of Sphagnum mosses ( p -hydroxyphenyl compounds, fucose) are concentrated in the surface layers: the acrotelm (from 0 to −20 cm) and the mesotelm (from −20 to −50 cm). Biomarkers of higher plant contribution (C 20+ fatty acids, C 22 and C 24 ω-hydroxy fatty acids, xylose and lignin compounds) are concentrated in the deeper layers of the peat core: the catotelm (from −50 to −100 cm).

International audience; Northern peatlands are estimated to store up to one third of all terrestrial carbon as peat and, even though a large extent of boreal peatlands is in pristine condition, extensive areas have been affected by natural or anthropogenic disturbance. Here, we aimed to study the bulk organic matter, elemental composition and molecular inventory of a peat disturbed by a clay deposit in the mesotelm layer (from −35 to −45 cm) due to mining activity near the peatland zone. We therefore investigated loss on ignition, elemental analysis, lignin monomers and non-cellulose carbohydrates, as well as the lipid fraction. In general, no significant impact on peatland evolution was noted, the only odd result being an increase in complex lipids containing acyl groups in the clay deposit zone, although this did not influence the distributions of the fatty acids, which had a bimodal distribution at C16 and C24/C26, typical of a non-impacted Sphagnum dominated peatland. Phospholipid analysis showed an increase in the quantity of mid-chain branched fatty acids, suggesting high sulfate reducing activity in the underlying clay deposit. Other lipid, lignin and carbohydrate biomarkers showed a normal peatland evolution, plant deposition being apparent in the bottom layer designated by the catotelm and microbial activity and production being highest in the upper layer, represented by the acrotelm and mesotelm.

Understanding the hydrological dynamics of boreal wetland ecosystems (peatlands) is essential in order to better manage hydropower inter-annual productivity at the La Grande basin (Northern Quebec, QC, Canada). Given the remoteness and the huge dimension of the La Grande basin, it is imperative to develop remote sensing monitoring techniques to retrieve hydrological parameters. The main objective of this study is to find out if multi-date and multi-polarization Radar Satellite 2 (RADARSAT-2) (C-band) image analysis could detect seasonal variations of surface soil moisture conditions of the acrotelm. A change detection approach through the use of multi temporal indexes was chosen based on the assumption that the temporal variability of surface roughness and natural vegetation biomass is generally at a much longer time scale than that of surface soil moisture (Δ-Index is based on a reference image that represents dry soil, in order to maximize the sensitivity of σ° to changes in soil moisture with respect to the same location when soil is wet). The Δ-Index approach was tested with each polarization: σ° for fully polarimetric mode (HH, HV, VV) and the cross-polarization coefficient (HV/HH). Results show that the best regression adjustment with regard to surface soil moisture content in boreal wetlands was obtained with the cross-polarization coefficient. The cross-polarization multi-temporal index enables precise volumetric surface soil moisture estimation and monitoring on boreal wetlands, regardless of the influence of vegetation cover and surface roughness conditions (bias was under 1%, standard deviation and RMSE were under 10% for almost all estimation errors). Surface soil moisture estimation was more precise over permanently flooded areas than seasonally flooded ones (standard deviation is systematically greater for the seasonally flooded areas, at all analyzed scales), although the overall quality of the estimation is still precise. Cross-polarization ratio image analysis appears to be a useful mean to exploit radar data spatially, as we were able to relate changes in wetland eco-hydrological dynamics to variations in the intensity of the ratio.

The development of northern high-latitude peatlands played an important role in the carbon (C) balance of the land biosphere since the Last Glacial Maximum (LGM). At present, carbon storage in northern peatlands is substantial and estimated to be 500 ± 100 Pg C (1 Pg C = 1015 g C). Here, we develop and apply a peatland module embedded in a dynamic global vegetation and land surface process model (LPX-Bern 1.0). The peatland module features a dynamic nitrogen cycle, a dynamic C transfer between peatland acrotelm (upper oxic layer) and catotelm (deep anoxic layer), hydrology- and temperature-dependent respiration rates, and peatland specific plant functional types. Nitrogen limitation down-regulates average modern net primary productivity over peatlands by about half. Decadal acrotelm-to-catotelm C fluxes vary between −20 and +50 g C m−2 yr−1 over the Holocene. Key model parameters are calibrated with reconstructed peat accumulation rates from peat-core data. The model reproduces the major features of the peat core data and of the observation-based modern circumpolar soil carbon distribution. Results from a set of simulations for possible evolutions of northern peat development and areal extent show that soil C stocks in modern peatlands increased by 365–550 Pg C since the LGM, of which 175–272 Pg C accumulated between 11 and 5 kyr BP. Furthermore, our simulations suggest a persistent C sequestration rate of 35–50 Pg C per 1000 yr in present-day peatlands under current climate conditions, and that this C sink could either sustain or turn towards a source by 2100 AD depending on climate trajectories as projected for different representative greenhouse gas concentration pathways.

This study deals with the palaeohydrological information obtained from lipids composition and vegetal tissue preservation of two peat cores from Asturias, North Spain. The two profiles differ in the type of peatland (raised bog in La Borbolla and blanket bog in Buelna) and the type of organic matter being more bryophytic in the raised bog and more herbaceous in the blanket bog. The peatlands are located close to the coast on impermeable, old flat erosion surfaces which favoured peat accumulation within a distance of 3.5 km from each other. The accumulation rate varied between 0.05 and 0.07 mm/yr and the records extend from around 9000 to 2500 cal. yr BP. The main differences between the two peat sites can be summarized as follows: the raised bog has lower mineral matter content and H/C atomic ratio and higher C/N ratio and extraction yields compared to the blanket bog. It has also a higher Tissue Preservation Index for Huminite macerals and increasing Inertodetrinite Index with depth. Regarding biomarkers, the raised bog has a relatively higher concentration of n-alkane-2-ones compared to the corresponding n-alkane of similar carbon number, higher concentration of medium- vs. high-molecular-weight-methyl-ketones and higher triterpenoids/steroids ratio than the blanket bog. Alternating humid/dry periods have been recorded in both profiles based on lipid concentrations indicating that the Sphagnum-rich intervals in the raised bog are more sensitive than the herbaceous blanket peat record to climatic variations. The main humid intervals identified are dated as 5000–7500 cal. yr BP in the blanket bog and as 6000–3500 cal. yr BP and last 2500 cal. yr BP in the raised bog and correlate with the humid periods traced in other peatlands locations in this region. The transition Middle-to-Late Holocene is characterized by humid conditions in the region which favoured the Sphagnum growth in the peats. The reflectance of huminite in these records appears to be more related with differences in the oxidative conditions than with variation of peat maturity. It is higher in the layers with high mineral matter content at the beginning of organic matter accumulation and also in the upper part of the profile subjected to seasonal desiccation. A more intense biochemical gelification coincides with higher concentration of hopanoids derived from bacteria in the upper part of the profile (acrotelm). High amount of nonadecan-2-one (K19) and high concentrations of triterpenyl acetates, which are also determined in other peat profiles from Northern Spain are also detected in these profiles. This indicates that the specific conditions required for the formation of these compounds, probably associated to wet temperate climate, dominated throughout the region., The financial support provided by the Spanish Ministry for Science and Innovation (CGL2009-13990-C02-01), MINECO (CGL2013-46458-C2-1-R) and ERD funds is gratefully acknowledged. J. Urbanczyk thanks MEC for a FPU fellowship.

Mechanical dewatering of wet mined peat produced peat mining process water (PMPW) with low pH (5.49) and high total suspended solids (TSS 432 mg L−1), Al (1.39 mg L−1), Fe (4.36 mg L−1), Hg (37.1 ng L−1), MeHg (0.485 ng L−1), Zn (55 μg L−1), total nitrogen (TN 7.92 mg L−1), total phosphorus (TP 303 μg L−1) and true colour (532 TCU). High removal efficiencies were calculated for acrotelm peat filters (mesocosms) used to treat PMPW (TSS 45–83%; particulate organic carbon (POC) 47–89%; metals 53–100%; TN 85%; TP 81%), though final mesocosm leachate concentrations did not all achieve Canadian Water Quality Guidelines. In one study, mesocosm leachate had higher colour and dissolved organic carbon (DOC) concentrations than PMPW. Our mesocosm studies suggest an initial reduction in PMPW solids be considered by industry before peatlands are used as treatment systems.

In order to develop new tools in the reconstruction of microbiological processes in ancient continental settings, we determined the concentration of archaeol and sn -2-hydroxyarchaeol in four Holocene ombrotrophic peatlands, spanning a range of European climate zones. Neither ether lipid was present in the aerobic acrotelm peat, consistent with an origin from anaerobic archaea, presumably methanogens. At the depth of the maximum seasonal water table, archaeol and sn -2-hydroxyarchaeol concentration markedly increased at all four sites, again consistent with an anaerobic source, but differed strongly among sites. The differences apparently reflect a combination of vegetation – ericaceous and graminoid plants as opposed to Sphagnum spp. and other mosses lacking root systems – and temperature influence on methanogenesis. In particular, low ether lipid concentrations in Finland probably reflect the lack of vascular vegetation possessing well-developed root systems, together with low mean annual temperature. Similarly low concentrations of archaeol and sn -2-hydroxyarchaeol in a German bog likely result from winter temperatures below 0 °C and a relatively shorter growing season. The occurrence of sn -2-hydroxyarchaeol is limited to a narrow and shallow depth range, indicating that it is poorly preserved, but archaeol persists throughout the cores. Decoupling the concentration of archaeol and the more labile sn -2-hydroxyarchaeol below ca. 50 cm suggests that the former records fossil biomass rather than living biomass. If so, then downcore variation in archaeol concentration likely reflects past changes in methane cycling, and archaeol, pending further developmental research, could serve as a new tool for reconstruction of past peatland biogeochemistry.

We investigated the changes of water level and vegetation in a restored cut-over raised bog in response to a hydrological protection zone established around the bog. The restoration began 1997 and techniques involved ditch blocking within and around the bog to stimulate a return to conditions of intact bog ecosystems. In order to monitor the rehabilitation of the raised bog, water levels and vegetation have been recorded since before restoration measures began. The monitoring is ongoing, but an assessment of 15 year’s data (1994–2008) is presented. A hydrological protection zone with continuous high water levels could be established around the raised bog which minimizes the runoff of precipitation. Shortly after the first measures, the water levels increased significantly at all dipwells. Parallel to the increasing water levels a vascular plant species assemblage and a diverse Sphagnum community developed. In particular Sphagnum fimbriatum, S. palustre, S. recurvum and S. squarrosum spread efficiently. The cover of trees decreased significantly because of high water levels and ongoing acidification by Sphagnum spp. The high water levels have stimulated the re-vegetation and the hydrology self-regulation of the acrotelm. The successful regeneration of the acrotelm particularly became apparent in years with below-average precipitations (e.g. 2008), when the water levels in the central parts of the raised bog did not fall back to the low level reached in previous years, which had also remarkably water deficits (e.g. 2003).

Northern peatlands are important shallow freshwater aquifers and globally significant terrestrial carbon stores. Peatlands are complex, ecohydrological systems, commonly conceptualized as consisting of two layers, the acrotelm (upper layer) and the catotelm (lower layer). This diplotelmic model, originally posited as a hypothesis, is yet to be tested in a comprehensive manner. Despite this, the diplotelmic model is highly prevalent in the peatland literature, suggesting a general acceptance of the concept. We examine the diplotelmic model with respect to what we believe are three important research criteria: complexity, generality and flexibility. The diplotelmic model assumes that all ecological, hydrological and biogeochemical processes and structures can be explained by a single discrete boundary—depth in relation to a drought water table. This assumption makes the diplotelmic scheme inherently inflexible, in turn hindering its representation of a range of ecohydrological phenomena. We explore various alternative conceptual approaches that might offer greater flexibility, including the representation of horizontal spatial heterogeneity and transfers. We propose that the concept of hot spots, prevalent in terrestrial biogeochemistry literature, might be extended to peatland ecohydrology, providing a more flexible conceptual framework. Hot spots are areas of a peatland which exhibit fast processing rates in a number of mechanistically linked hydrological, ecological and biogeochemical processes. The complementary concept of cold spots may also be useful in peatland ecohydrology, particularly with regards to understanding the vulnerability of peatlands to disturbance. The flexibility of our suggested scheme may allow the future incorporation of ecohydrological phenomena yet to be identified as important in peatlands. Copyright  2011 John Wiley & Sons, Ltd.

The stratigraphy of four peat sequences collected in two peat bogs located in the Eastmain River watershed (52° N, 76° W), James Bay lowlands, Quebec, Canada, was investigated to reconstruct past hydroclimatic conditions of peat accumulation and associated carbon dynamics during the late Holocene. Analyses of macrofossils, testate amoebae, peat humification, C/N ratio and bulk density were performed at high-resolution along each peat core, allowing the potential of each proxy indicator under varying nutrient status and hydroclimatic conditions to be evaluated. Some synchronous changes were recorded both within and between peatlands, suggesting the influence of allogenic factors in the development of these peatlands. Other reconstructed changes have highlighted autogenic succession processes related to the local geomorphic and hydrologic context. Highest peat carbon accumulation rates (LORCA) were correlated with either wet conditions or high woody debris percentages, suggesting that residence time of the biomass in the acrotelm and the nature of plant material can both influence carbon accumulation rates in peat bogs. This study provides the first high-resolution paleoecohydrological reconstructions from the mid-boreal ecoregion of eastern Canada, a region in which peatlands occupy 30 to 60% of the land surface.

Recent advances in peatland restoration techniques have succeeded in establishing Sphagnum moss on the remnant cutover peat surface following peat extraction; however, evaluating restoration success remains a key issue. We argue that a Sphagnum-dominated peatland can only be considered functionally ‘restored’ once organic matter accumulation has achieved a thickness where the mean water table position in a drought year does not extend into the underlying formerly cutover peat surface. Here we monitor the spatio-temporal development of organic matter accumulation in a new peat layer for the first 8 years following the restoration of a Quebec peatland and couple a simple acrotelm carbon accumulation model and ecohydrological model to assess peatland restoration success. We determined that organic matter accumulation increased from 2.3 ± 1.7 cm 4 years post-restoration to 13.6 ± 6.5 cm 8 years post-restoration. For comparison, at an adjacent non-restored section of the peatland organic matter accumulation was significantly lower (p

We have developed a new approach to quantitatively reconstruct past changes in evaporation based on compound-specific hydrogen isotope ratios of vascular plant and Sphagnum biomarkers in ombrotrophic peatland sediments. We show that the contrast in H isotopic ratios of water available to living Sphagnum (top 20 cm) and in the rooting zone of peatland vascular plants can be used to estimate “ƒ”—the fraction of water remaining after evaporation. Vascular plant leaf waxes record H isotopic ratios of acrotelm water, which carries the D/H ratio signature of precipitation and is little affected by evaporation, whereas the Sphagnum biomarker, C 23 n -alkane, records H isotopic ratios of the water inside its cells and between its leaves, which is strongly affected by evaporation at the bog surface. Evaporation changes can then be deduced by comparing H isotopic ratios of the two types of biomarkers. We calibrated D/H ratios of C 23 n -alkane to source water with lab-grown Sphagnum . We also tested our isotopic model using modern surface samples from 18 ombrotrophic peatlands in the Midwestern United States. Finally, we generated a 3000-year downcore reconstruction from Minden Bog, Michigan, USA. Our new record is consistent with records of other parameters from the same peatland derived from different proxies and allows us to differentiate precipitation supply and evaporative loss.