Peat Growth Research Articles

Climate-driven peatlands development and vegetation dynamics in Northeastern China since the mid-Holocene: New evidence from Huanan peatlands

Studying peatland evolution and vegetation patterns in response to climate change provides valuable insights into future ecosystem trends. This study focuses on the Huanan peatland located in Changbai Mountain regions in Northeast China, utilizing phytolith analysis and stable carbon isotope composition (δ13C) to reconstruct late Holocene vegetation dynamics. Additionally, grain size, total organic carbon (TOC), and total nitrogen (TN) analyses were conducted to understand peatland development and paleoclimate since the late Holocene. The research identifies three distinct climate periods since 5500 cal yr BP: an initial warm, humid phase (5500–4000 cal yr BP) characterized by high river levels that formed lacustrine sediments; a subsequent transition to cold, dry conditions (4000–1500 cal yr BP) that initiated peat formation; and continued dry, cold conditions (1500 cal yr BP to the present) with sustained peat growth. Phytolith data reveal a dominant forest vegetation type since 2000 cal yr BP, further divided into three periods: 2000–1300 cal yr BP, marked by diverse and dense vegetation; 1300–750 cal yr BP, with declining plant cover; and 750 cal yr BP to the present, characterized by an increase in woody plants but a reduction in local grass cover.

Exploring the Holocene rise, disturbance and decline of pine forests in the river valleys of northeastern Belgium using pollen and botanical macroremains

The Holocene evolution of vegetation and environment in the Kleine Nete valley in the coversand region of northeastern Belgium is studied through sedimentological, palynological and macrobotanical analysis of a radiocarbon dated peat sequence. Peat formation started at the beginning of the Holocene in mesotrophic fen conditions. After a period of fast peat growth, the accumulation slowed down and the peat surface became dry in the Middle Holocene.The palynological results are compared with other pollen data from the region, in order to establish a regional pollen biozonation for the Early and Middle Holocene in the Nete Basin. This shows that pine has long been a characteristic element in the Nete Basin. Pine forest expanded immediately after the 11.4 cold event, which is earlier than in the western Scheldt Basin. Pine and birch grew along the valley, possibly also within the peatland. Peaks of microcharcoal, herbs and/or coarse sediment in the peat reflect temporary local forest disturbances in the Early Holocene. Some may reflect small-scale controlled fires induced by hunter-gatherers, although a natural cause seems much more plausible given the dominance of fire-associated pines and increased drought. Pine remained important throughout the Early Holocene. This long-lasting predominance of pine in the Nete Basin, compared to elsewhere in the Scheldt Basin, is likely related to the poor sandy subsoil in the region, which hinders more nutrient-demanding broadleaf trees to overtake.

Rate of permafrost thaw and associated plant community dynamics in peatlands of northwestern Canada

Abstract The most rapid climate warming is occurring in northern, permafrost environments. Peatlands of these regions are particularly sensitive to climate warming, with the high ground ice content of peat plateaux resulting in the formation of collapse scars as ground temperatures warm. To quantify the rates of permafrost thaw and associated vegetation changes, we sampled the plant and lichen communities in transects spanning actively thawing collapse scar margins at sites from mid‐Boreal to Low Subarctic conditions, within Canada's Northwest Territories. Seventeen transects were sampled in 2007/08 and 14 of these were resampled 10 years later. The rate of lateral permafrost thaw of collapse scar margins ranged from −6 to 63 cm year−1 (mean: 22.0 cm ± 4.7 cm year−1 (SE)); variability was high and no trends with respect to latitude or temperature gradients were detected. Plant communities displayed a clear gradient from lichen‐ and ericaceous shrub‐dominated peat plateaux, to collapse scars primarily characterized by Sphagnum mosses and graminoids. Both space‐for‐time (distance from collapsing margin) and direct measurement of 10‐year changes showed a successional sequence following permafrost thaw; floating mat communities characterized by Sphagnum riparium or S. balticum proceeded to lawn communities of S. angustifolium and, finally, to hummock communities with Mylia anomala or S. fuscum. This successional sequence was associated with increased water table depth and lower soil water content in plant communities farther from the actively collapsing front, illustrating that peat growth above the water table was driving plant community successional changes. The most rapid plant community succession occurred in recently thawed environments as peat growth propelled the ground surface above the water table while the slowest succession occurred in the collapse scar hummock communities located farthest from the actively collapsing peat plateau margin. Synthesis. In just 10 years, significant vegetation change was detected, in association with both permafrost thaw and subsequent plant community succession. These changes occurred across a broad climatic and latitudinal gradient, from mid‐Boreal to Low Subarctic and have implications for wildlife, global C cycle and indigenous communities who depend on this landscape for harvesting, spiritual and cultural practices.

Conservation efforts for Geronggang Trees (Cratoxylum arborescens (Vahl.) Blume) as a function of peatland restoration and protection in Bengkalis Regency

Bengkalis is the region that has the largest peatland in Riau Province. However, 57 percent of the peatland conditions in Bengkalis have been degraded due to careless land clearing for plantation land, resulting in land drying, surface subsidence, and flammability. Efforts to restore peatlands in Bengkalis are being carried out by utilizing local plants whose presence is increasingly depleting, namely Geronggang tree (Cratoxylum arborescens (Vahl.) Blume). This research provides information regarding the conservation efforts of Geronggang trees by the Bengkalis local community in supporting peatland restoration by making observations and collecting secondary data. Observation results show that Geronggang tree has ecological, social, and economic benefits for the local Bengkalis community. Bengkalis people have their way of cultivating Geronggang trees; Geronggang seeds are planted using a mixed planting system, and Geronggang harvesting is carried out using thinning cutting, alley cutting (lane), and embroidery cutting systems. This stage is carried out to maintain the humidity of the peat land in each passage and to maintain the continuity of peat growth. Thus, conservation carried out by the Bengkalis local community must be able to keep the ecological and environmental functions of degraded peat areas. The research concludes that the Geronggang tree is a habitat and plant that grows and lives on peatlands in the Bengkalis area.

Multi-proxy evidence for woodland clearance in northeast Northumberland (England) during the Iron Age

Pollen diagrams covering the Bronze Age to Roman period from northeast Northumberland are scarce. We present a 14C-dated pollen record from a peat-filled forest hollow in Chillingham Wild Cattle Park, northeast Northumberland, that spans the Iron Age. For the first time for this part of Northumberland, fungal spores are also analysed to investigate whether clearances took place in the context of crop cultivation or pastoralism. The pollen diagram shows significant woodland cover during the Late Bronze Age, with small-scale landscape openness potentially representing crop cultivation and animal grazing under a tree canopy. A local clearance event, with arboreal pollen falling to 13.2%, is radiocarbon dated to the late Early to Middle Iron Age, likely coinciding with the construction and occupancy of the nearby Ros Castle hillfort. A significant rise in dung fungal spores and the presence of Plantago and other open vegetation taxa indicate animal husbandry played an important role in this clearance phase. A subsequent large decrease in dung fungi and a small rise in arboreal pollen may reflect a degree of abandonment of the area after the climate cooled. Peat formation ceased in the late Middle to Late Iron Age as the hollow filled up. Limited renewed peat growth occurred in the last century or so, after peat shrinkage due to drying and consequent oxidation provided the possibility for renewed peat formation within the hollow.

Coal petrology, sedimentology and depositional environment of the Parvadeh coals in the Upper Triassic, Tabas Block of Central-East Iran

Peat forming environment strongly influences the economic value of any coal seam and coal-bearing strata. Hence, palaeoenvironmental studies provide important information for coal resource exploration. In this context, detailed studies on selected coals from the Parvadeh Area, Iran, were conducted using sedimentology, coal petrology, X-ray diffraction (XRD), scanning electron microscopy- energy dispersive X-ray analyzer (SEM-EDX), and proximate analysis. The sedimentary facies above and below the coal seams are mainly marine or marine-influenced facies, supporting that the coal-forming mires in the Parvadeh Area developed in a paralic environment, where the base level must be closely related to sea level. Sulfur contents are moderate to high and mark the influence of brackish/marine water, especially during transgression after peat growth in a lower delta plain environment. The peat-forming mires extended on coastal/delta plain lobes. The lower delta plain/coastal plain coals are characterized by lateral continuity and substantial thickness, whereas few coals possibly representing the upper delta plain are thin and more discontinuous. The detrital nature and composition of the numerous partings and the overall high ash yield in the coal seams indicate an active tectonic area with high rates of creation of accommodation space over peat growth. Coal petrology and coal facies analysis exhibits a permanently high water table within a forest swamp and mostly rheotrophic conditions, sometimes with connection to the seawater. According to paleoenvironmental reconstructions, it seems that coal layers may be thicker, with less sulfur (pyrite), but more clastic minerals and partings toward the western part of the area. Although these coal seams presently have low economic potential for the mining operation, partly due to great depth, this humic, high-volatile to medium-volatile bituminous coal may be suitable for exploration of coal bed methane resources.

Recent carbon sequestration dynamics in four temperate SE European peatlands using 210Pb dating

The last two centuries’ anthropogenically-accelerated climatic changes and elevated atmospheric levels of CO2 are influencing the recent carbon sequestration dynamics of peatlands, resulting in high variations of growth rates, and a general ascending trend in apparent carbon accumulation rates. In the present work, 210Pb high-resolution chronologies and 137Cs alternative markers were employed to study the recent carbon-related peat properties and their evolution throughout the last two centuries in four Sphagnum-dominated bogs in SE Europe (Romania). The results revealed a recent apparent carbon accumulation rate ranging from 9.5 to 437.5 g C m−2 yr−1, with a mean value of 144 ± 90.1 g C m−2 yr−1, that yielded an average increase of 18.25% of the rate from 1950 to the present period, suggesting an enhanced contemporaneous C uptake and storage in the peatlands. The mean C storage per unit area was 17.6 ± 7.6 kg C m−2. The periods of decreased peat growth rates were identified and attributed to significant drought events at the regional scale. The results found in the present study confirm the observations and trends remarked by other researchers in the literature, and further reinforce the relevance of studying recent carbon dynamics in peatland ecosystems. The obtained 210Pb chronologies were validated by 137Cs markers, highlighting the suitability of this technique for peat profile dating.

Different hydrological controls causing variable rates of Holocene peat growth in a lowland valley system, north-eastern Netherlands; implications for valley peatland restoration

The Drentsche Aa valley system in the glacial sandy landscape of the north-eastern Netherlands, is one of the many regional drainage systems in the north-western to central European Lowlands. Following deep incision in the Weichselian, ca 7 m of eutrophic peat has accumulated in the lower to middle reaches of the valley system in the Holocene, completely filling the Weichselian incision. We reconstructed the rate of water-level rise controlling peat growth at three locations in the valley system (representing the upper, middle and lower reaches), using 14C peat dates from compaction-free sampling sites on the sloping valley margin where the peat directly overlies the sandy Pleistocene subsurface. The 14C dates enabled the construction of curves showing the water-level evolution at each location. Our results show variable rates of Holocene peat growth in the valley system in response to different drivers of hydrological change: a strong increase in annual precipitation (onset Holocene), a decrease in evapotranspiration (10,000–8000 cal. years BP) and relative sea-level rise (after ~4500 cal. years BP). Because the identified hydrological controls on peat growth are regional, they probably ruled Holocene peat growth in many peat-filled valley systems in the north-western to central European Lowlands. Currently, there is growing attention for these valley systems in the context of European nature restoration efforts and climate change adaptation and mitigation measures. The present study underscores that large-scale hydrological measures outside the valley system are needed for restoration of degraded valley peatlands.

Testate amoebae response and vegetation composition after plantation removal on a former raised bog

Extensive drainage of peatlands in north-west Europe for the purposes of afforestation for timber production and harvesting has altered the carbon balance and biodiversity value. Large-scale restoration projects aim to reinstate hydrological conditions to keep carbon locked up in the peat and to restart active peat growth. Testate amoebae are an informal grouping of well-studied protists in peatland environments and as microbial consumers play an important role in nutrient and carbon cycling. Using a space for time substitution approach, this study investigated the response of testate amoebae assemblages and vegetation composition after tree removal on a drained raised bog. There was a clear difference in microbial assemblages between open and a chronosequenceof restoration areas. Results suggest microbial recovery after rewetting is a slow process with plant composition showing a faster response than the microbial assemblage. Mixotrophic testate amoebae had not recovered seventeen years following plantation removal and the establishment of Sphagnum mosses in the wetter microforms. These results suggest that vegetation composition and Testate amoeba assemblages respond differently to environmental drivers at forest-to-bog restoration areas. Local physicochemical peat properties were a stronger driver of the testate assemblage compared with vegetation. Complete recovery of microbial assemblages may take place over decadal timescales.

PALEOECOLOGICAL CONDITIONS AND CARBON ACCUMULATION IN GENESIS OF INUNDATED MIRE OF MID-RUSSIAN UPLAND

The aim is to study of influence of the ecological conditions on the carbon accumulation at the different stages of genesis of the inundated mire.
 Materials and methods. The macrofossil analysis and the degree of peat decomposition were studied by the microscopic method, the moisture content and the dry bulk density were studied by the gravimetric method. The ash content was determined by burning, the content of organic matter was calculated by the difference between the mass of dry peat and the ash content. The carbon content (%) in peat samples was calculated based on the dry bulk density, the organic matter content and the mass fraction of carbon for each volume of peat. The rate of vertical growth of peat and intensity of peat accumulation in periods of Holocene were calculated based on the results of radioactive dating.
 The parameters of surrounding landscapes during the mire genesis were characterized by the results of the palynology analysis and the estimation of fire activity. The intensity of fires in paleolandscapes was studied by the content of coal particles in each (1 cm3) sample of wet peat.
 Results. The genesis of the Podkosmovo mire is presented by 5 stages which were took place under the stable conditions of water-mineral nutrition. The carbon accumulation in the genesis proceeded at the rate of 45.7 g/m2/year on average. At the same time, the surrounding landscapes differed in the degree of afforestation and the intensity of anthropogenic press.
 Conclusion. The moderate hydration and nutrition with mineralized waters ensure the stability of the mire development and the intensity of carbon accumulation, despite the change of surrounding landscapes under the influence of climate or human. However, the active transformation of the surrounding landscapes can have a negative impact on the functioning of the mire and reduce the intensity of carbon accumulation.

Large deltas, small deltas: Toward a more rigorous understanding of coastal marine deltas

Deltas are subaerial landforms that cap underlying deposits with subaqueous extensions that result from a river feeding sediment directly into a standing body of water at a rate that overwhelms any effective dispersal processes derived from the ambient basin. This definition encapsulates both the terrestrial surface expression and the geological focus on the entire sediment mass. Environmental studies also focus on the ecology of deltaic wetlands, their drowning history, and related sustainability issues including societal considerations, history, and culture. A mean 76 ± 16% drop in hydraulic energy occurs in all subaerial deltas regardless of size, given the break in gradients separating fluvial and deltaic surfaces, driving an ever-decreasing bed-material transport, shallowing of distributary channels and concomitant overbank flooding. A delta's sediment mass grows from the addition of new river loads but can also include aeolian and marine sediment derived from outside the delta domain, growth of peat and other biomass, and inputs from human action. Removal of sediment is via river plumes interacting with marine currents, wave-induced transport, sediment failures and gravity flows, high-tide inundation onto the delta plain, tidal channel widening and deepening, and human action (peat, clay, sand and gravel mining). A delta's trapping efficiency ranges from 0 for small-load rivers that discharge directly into an energetic ocean, to 80% for large deltas, and up to 100% for some semi-enclosed bayhead deltas, including fjords. The global (ensemble) subaerial delta aggradation rate is ∼1.6 mm/y if 70% of the global sediment load exits the river mouth(s), a reminder of how much sediment can be expected to be delivered to the surfaces of global deltas at a time when the 2022 CE sea level rise is ∼4 mm/y. At the planetary scale, deltas are environmentally complex given Earth's range in climate, hydrodynamics, tectonic settings, relative sea-level provinces, sediment input, redistribution processes, and human actions. Under natural conditions, the subaerial portion of deltas adapt to change by advancing, retreating, switching, aggrading, and/or drowning, whereas many modern deltas are structurally constrained by societal needs. The 89 large and mud-rich coastal marine deltas (i.e. subaerial area > 1000 km2) account for 84.3% of Earth's total deltaic area that hosts >89% of all humans occupying deltas, many living within megacities. The 885 medium-size deltas (i.e. subaerial areas 10–1000 km2) account for 15.5% of the global delta area and 10.5% of humans living on deltas, with characteristics that fall between the small and large delta categories. The 1460 small and essentially sandy deltas (1–10 km2), including all fjord deltas, are impacted less from human action (with exceptions) and most are better able to withstand climate change. Recognizing the limits of big data in capturing delta complexity, field data remains a necessary gold standard for site investigators.

De verdwenen Eems, een participatieproject in het grensgebied

The lost Ems, a participatory project in the border region. Since 2017, the GIA and NLD have conducted joint research into a fossil branch of the river Ems between Landegge (Ldkr. Emsland) and Sellingen (prov. Groningen), where this branch merged with the Runde system as the Ruiten Aa/Westerwoldsche Aa. As its flanking river dunes were intensively exploited by farming communities up to the middle/late Iron Age, this string of settlements became an umbilical cord linking the Westerwolde region with the Ems bank, especially after accelerated peat growth intensified the barrier posed by the Bourtanger Moor. Mapping the fossil river, its regime and riverbank occupation as well as its abandonment goes hand-in-hand with involving today’s landowners and local residents, explaining to them that there is more to the supposedly poor cultural history of this hinterland zone than the era of peatbog exploitation and the Emslandlager during WWII.

N and P use efficiencies of basil cultivated in organically fertilized growing media

• Growing media (GM) are the main driver of Basil N- and P- use efficiencies. • Peat provided the best growth conditions under organic fertilization. • Microbial N competition limited basil growth in woody-based GM. • Organic fertilizer localization and PGPR inoculum weakly alleviated N limitation. • Peat will be difficult to replace especially with woody constituents in GM. Sustainable production in soilless cultivation systems may be achieved by using recycled organic materials as constituents of growing media (GM) and as organic fertilizers. Synchronizing nutrient releases from organic fertilizer mineralization with plant needs in containerized production is difficult to manage for greenhouse growers. This is further amplified by the diversification of GM constituents, driving microbial activities. We aimed to evaluate how the plant can adapt its nutrition to different organic fertilization strategies and ensure its growth depending on the GM and organic fertilizer types. Ocimum basilicum L. was grown for 60 days in a greenhouse in pots filled with three different GM: 100% peat (Peat); 70% peat and 30% coir fiber (GM1); and 50% coir pith, 25% composted bark, 25% wood fiber (GM2). Two contrasted organic fertilizers were used (horn and a granular fertilizer), mixed to the GM, localized in the pot, or combined with Bacillus sp. inoculation as plant growth-promoting rhizobacteria (PGPR). Standard mineral fertilization mixed to the GM was also used as a control treatment. We investigated basil growth (height, biomass, leaf area, chlorophyll and flavonol contents) as well as nitrogen (N) and phosphorus (P) use efficiencies, from their uptake by the roots to their allocation to the plant organs. Basil performances were mainly affected by the GM type. Peat provided optimal conditions for plant development. In GM1, basil maximized the utilization of available N and P taken up from the GM and reached the highest biomass production. Basil performances were especially low when it was grown on GM2 because of a strong competition for N between microbes and the roots. The fertilizer type, its localization and PGPR inoculation did not affect basil growth or nutrition in peat; these treatments had only little effect on basil grown on GM1 and GM2, and affected its performances differently depending on the GM type. This study provides evidence that fertilization must be thoughtfully managed depending on the GM in organically fertilized systems.

Dating basal peat: The geochronology of peat initiation revisited

Attributing the start of peat growth to an absolute timescale requires dating the bottom of peat deposits overlying mineral sediment, often called the basal peat . Peat initiation is reflected in the stratigraphy as a gradual transition from mineral sediment to increasingly organic material, up to where it is called peat. So far, varying criteria have been used to define basal peat, resulting in divergent approaches to date peat initiation. The lack of a universally applicable and quantitative definition, combined with multiple concerns that have been raised previously regarding the radiocarbon dating of peat, may result in apparent ages that are either too old or too young for the timing of peat initiation. Here, we aim to formulate updated recommendations for dating peat initiation. We provide a conceptual framework that supports the use of the organic matter (OM) gradient for a quantitative and reproducible definition of the mineral-to-peat transition (i.e., the stratigraphical range reflecting the timespan of the peat initiation process) and the layer defined as basal peat (i.e., the stratigraphical layer that is defined as the bottom of a peat deposit). Selection of dating samples is often challenging due to poor preservation of plant macrofossils in basal peat, and the representativity of humic and humin dates for the age of basal peat is uncertain. We therefore analyse the mineral-to-peat transition based on three highly detailed sequences of radiocarbon dates, including dates of plant macrofossils and the humic and humin fractions obtained from bulk samples. Our case study peatland in the Netherlands currently harbours a bog vegetation, but biostratigraphical analyses show that during peat initiation the vegetation was mesotrophic. Results show that plant macrofossils provide the most accurate age in the mineral-to-peat transition and are therefore recommendable to use for 14 C dating basal peat. If these are unattainable, the humic fraction provides the best alternative and is interpreted as a terminus-ante-quem for peat initiation. The potential large age difference between dates of plant macrofossils and humic or humin dates (up to ∼1700 years between macrofossil and humic ages, and with even larger differences for humins) suggests that studies reusing existing bulk dates of basal peat should take great care in data interpretation. The potentially long timespan of the peat initiation process (with medians of ∼1000, ∼1300 and ∼1500 years within our case study peatland) demonstrates that choices regarding sampling size and resolution need to be well substantiated. We summarise our findings as a set of recommendations for dating basal peats, and advocate the widespread use of OM determination to obtain a low-cost, quantitative and reproducible definition of basal peat that eases intercomparison of studies. • We present three detailed radiocarbon sequences of the mineral-to-peat transition. • Basal peat needs to be clearly defined based on a quantitative reproducible parameter. • Peat initiation is a process of a certain timespan rather than an event. • Plant macrofossil dates are most accurate, humic/humin dates are likely too young. • A conceptual framework and recommendations for dating peat initiation are presented.

Unknown effects of daily-scale solar activity on the plant growth: Data from 6-year growth monitoring of Sphagnum riparium.

The influence of solar activity on plant growth has been studied for over 100 years, however, this phenomenon is still poorly understood on a daily scale. The data from extensive monitoring of the growth of peat moss Sphagnum riparium, which we are conducting in the mires of Karelia (Russia), may shed light on this issue. During the 6 years of observation, 161,190 shoots were measured, and 1075 growth rates were obtained. Considering together the growth rates with the sunspot number and involving data on seasonal temperature, we found previously unknown effects of daily-scale solar activity on plant growth. It was found that the sunspot number weakly but significantly inhibits the growth of Sphagnum. The extreme sunspot number in the 4 days before the growth rate values have a stronger influence. The involvement of temperature data showed that inhibition in growth is observed only in the temperature range from 6.7°C to 15.3°C and disappears beyond these limits. In addition, the data obtained showed that the influence of sunspot number on the growth of Sphagnum is progressively increasing along the gradient from the minimum to the maximum of the 11-year solar cycle. The study provides one of the first results on the effect of solar activity on plant growth on a daily scale. The results expand our knowledge of the biological effects of solar activity. Indirectly, they can also be useful to better our understanding of the ozone layer's involvement in this process.

Holocene and recent fires influence on soil organic matter, microbiological and physico-chemical properties of peats in the European North-East of Russia

The influence of fires on the development and chemical composition of two Rheic Hemic Histosols in the native territory of the middle taiga of the Komi Republic was estimated. The development of peat on site I (SI) located in the south boarder of the middle taiga began in the Boreal period (about nine ths. years ago14C yr BP). The growth of peat on site II (SII) located at the foothills of the Northern Urals started in the middle of the Atlantic Holocene period (about 6.7 ths. years ago14C yr BP). This work shows that during the time of development, peatlands experienced various pyrogenic events. The organic horizons were burned out and often led to a change in the dominant ground cover plants. Also, the charcoal particles formed during the fire at the forest surrounding the bogs were transported by air and accumulated in the peat. The pyrogenic history of the studied peats is different, the SI was subjected to intense fires at least twice: at the beginning of formation and in the modern period (140 years ago). The Histosol on SII experienced only low-intensity and indirect fire effect. The highest burning activity of nearest forests in both sites estimated based on charcoal content occurred at the end of the Atlantic, middle of the Subboreal periods. It was shown that an increase in the aromatic compounds occurs in horizons with pyrogenic features; in some cases, an increase in the concentration of polycyclic aromatic hydrocarbons (PAHs) was revealed. The aromatic compounds content in the SOM is determined by the content of macroscopic charcoal particles with significant correlation (CAr-H(C), R = 0.49, p < 0.05, CAr-O,N, R = 0.68, p < 0.05). It is shown that a high frequency of fires leads to an increase in carbon stocks at Histosols.

Climate-driven Holocene ecohydrological and carbon dynamics from maritime peatlands of the Gulf of St. Lawrence, eastern Canada

Anticosti Island, located in the Gulf of St. Lawrence (GSL; Quebec, Canada) is covered by ~25% peatland ecosystems, and conditions supporting their development remain poorly documented. We present the first reconstructions of the ecohydrological conditions (vegetation successions and water table variations) and related carbon accumulation of two maritime peatlands (Pluvier; PLU and Pointe de l’Est; PTE) located on the eastern part of Anticosti Island. These ombrotrophic peatlands developed under the influence of the GSL sea-surface conditions in interaction with atmospheric circulation during the Holocene. Long-term apparent Rate of Carbon Accumulation (LORCA, g C m−2 a−1) at PLU (13.3) and PTE (16.8) are lower than the mean global value for northern peatlands (22.9), likely due to high wind exposure. Results show that despite the earlier peat inception at PLU (9440 cal a BP) before PTE (6250 cal a BP), the fen-bog transition of both peatlands occurred almost synchronously (4540 and 5070 cal a BP respectively), suggesting favourable hydroclimatic conditions for peat growth. A slowdown in peat accumulation combined with dry and variable hydrological conditions after ca. 3300 cal a BP in the two studied peatlands coincided with the transition from the mid-Holocene to the Neoglacial cooling. At ca. 800 cal a BP, the shift from wet Sphagnum to dry ligneous peat corresponds to the transition from the Medieval Climate Anomaly to the Little Ice Age. Cooling periods, characterized by a decrease in incident solar radiation and the incursion of cold and dry Arctic air masses into the GSL, are marked by a decrease in peat accumulation, especially at PLU, due to its higher wind exposure, which influenced reduced snow cover thickness as well as frost penetration and duration through the peat.

Petrology, palynology, and geochemistry of the Pond Creek coal (Pennsylvanian, Duckmantian), Pike County, Kentucky: Overprints of penecontemporaneous tectonism and peat doming

The petrographic, palynologic, and geochemical character of the high volatile A bituminous Pennsylvanian (Bashkerian, Duckmantian) Pond Creek coal was evaluated for a series of mine samples in the Lick Creek and Jamboree 7 ½’ quadrangles in Pike County, Kentucky. In its prime years of production, the Pond Creek coal was among the most important coal resources in the leading coal producing state in the U.S. The thickness and quality of the Pond Creek coal was closely related to its position relative to the northwestward-plunging, N20°E-trending Belfry anticline with the main bed of the coal thinning and the thickness of rock between the latter and the high-S Pond Creek rider bed thinning across the anticline. This suggests that the Belfry anticline and the Pond Creek mire were contemporaneous features, with the rising anticline influencing the lithology and chemistry of the peat. Within the study area, the lower three lithotypes fill the original topography and the next higher lithotype pinching out along the rise towards the anticline. The next three lithologies, a thick bright zone (zone 4 in the nomenclature of this study), a bone coal, and a thinner bright zone are continuous through the study area, although they all thin towards the anticline. The upper durain, the termination of the coal seam, also pinches out towards the anticline. Zone 4 shows a decrease in total vitrinite towards the uppermost bench of the zone, an upwards increase in ash yield, the upwards increase in the floral diversity, and a higher concentration of Mn, CaO, and Ba + Sr in the lower lithologies of the zone. Towards the anticline, there is a greater floral stability within zone 4 compared to the relatively subsiding area to the east. Within the zone 4 bright lithologies, peat growth outpaced the level of the water table, but at the cost of the turnover of the arborescent lycopod forest to a more diminutive flora, the collapse of the ombrogenous peat, and the influx of deeper water and the consequent deposition of the overlying relatively high-ash bone coal.

The contribution of Antarctic moss peat to the understanding of global peatland processes

AbstractThe moss banks of the Maritime Antarctic composed of one or both of the mosses Chorisodontium aciphyllum and Polytrichum strictum form peat banks up to 3.4 m thick and 5500 years of age. They represent perhaps the simplest peat-forming systems in the world, so studying their dynamics can help in the understanding of peatland dynamics generally, particularly those of temperate blanket peat. They can provide insights into how the balance of growth, decomposition and compaction of peat results in peat formation, how downhill creep can be the cause of both vertical edges and the creation of patterned bogs and how erosion of peat can be a natural process.

The origin of alkaline fen in the Mosbeek Valley in the Netherlands is due to human impact rather than a natural development

Alkaline fens are important Natura 2000 habitats, which harbor many endangered plant species. Alkaline fens are formed in areas with groundwater discharge and usually developed in a natural way in the early Holocene. We radiocarbon dated the base of three peat deposits from spring fens along the flanks of the ice-pushed ridge near the village of Ootmarsum to find out when and why peat-forming vegetation started to grow. We cored a sequence in the Mosbeek Valley for detailed paleoecological analyses of micro- and macrofossils. To our surprise, we found strong evidence for human impact during the 13th and 14th centuries AD as the triggering factor for starting organic colluvial accumulation and peat growth at sites where natural springs are present. This shows that this fen is not a relic, but results from changes in land use. Human actions were: (1) deforestation causing increased run-off and reduced evaporation on the plateaus by the vegetation, resulting in increased seepage in the valleys, (2) intensification of agriculture, trade routes, and paired erosion, which formed colluvial deposits and sediment fans that hampered fast run-off water, (3) increased back and groundwater levels after the foundation of watermills; four lowering water levels due to intensification and reorganization of water use by new watermills, and (4) head cut erosion and spring erosion after privatization and cultivation of common pastures after the mid 19th century. This means that cultural-historical changes in the landscape were much more important for alkaline fens than expected.