Explore the vast range of titles available.

Peatland trees are valuable archives of paleoclimatic information; however, gaps persist in understanding the relationships between tree growth, peatland hydrology, and hydroclimate variables. While previous research in peatlands has mainly focused on tree-ring widths (TRW), yielding inconclusive results, the potential of stable carbon ([delta].sup.13 C) and oxygen ([delta].sup.18 O) isotopes in tree rings remains unexplored. In this study, we develop TRW, [delta].sup.13 C, and [delta].sup.18 O chronologies of Scots pine trees located in a Swedish peatland and a reference site on bedrock with a mineral soil layer. We assess their responses to hydroclimate conditions and evaluate their potential for reconstructing hydroclimate variations. Our findings show significant differences in mean TRW and [delta].sup.13 C values between the peatland and reference sites. Moreover, while TRWs do not exhibit distinct common patterns between sites, both [delta].sup.13 C and [delta].sup.18 O site chronologies show uniform year-to-year variations across all sites. Some discrepancies for TRW and [delta].sup.13 C site chronologies emerge, however, regarding multi-decadal trends. While the climate sensitivity of TRW is weak and non-homogenous, the [delta].sup.13 C and [delta].sup.18 O peatland and reference chronologies contain robust and consistent signals, with a maximum sensitivity to water table, precipitation, and vapor pressure deficit (VPD) variations during summer. Both [delta].sup.13 C and [delta].sup.18 O chronologies show stable relationships with three key hydroclimate variables over time. In conclusion, while TRWs from living peatland pines at our sites have limited potential to record high-frequency hydroclimate information, [delta].sup.13 C and [delta].sup.18 O chronologies can serve as excellent proxies for the reconstruction of past hydroclimate changes.

Drainage in tropical peatlands increases CO.sub.2 emissions, the rate of subsidence, and the risk of forest fires. To a certain extent, these effects can be mitigated by raising the water table depth (WTD) using canal or ditch blocks. The performance of canal blocks in raising WTD is, however, poorly understood because the WTD monitoring data are limited and spatially concentrated around canals and canal blocks. This raises the following question: how effective are canal blocks in raising the WTD over large areas? In this work, we composed a process-based hydrological model to assess the peatland restoration performance of 168 canal blocks in a 22 000 ha peatland area in Sumatra, Indonesia. We simulated daily WTD over 1 year using an existing canal block setup and compared it to the situation without blocks. The study was performed across two contrasting weather scenarios representing dry (1997) and wet (2013) years. Our simulations revealed that, while canal blocks had a net positive impact on WTD rise, they lowered WTD in some areas, and the extent of their effect over 1 year was limited to a distance of about 600 m around the canals. We also show that canal blocks are most effective in peatlands with high hydraulic conductivity. Averaging over all modeled scenarios, blocks raised the annual mean WTD by only 1.5 cm. This value was similar in the dry (1.44 cm) and wet (1.57 cm) years, and there was a 2.13 fold difference between the scenarios with large and small hydraulic conductivities (2.05 cm versus 0.96 cm). Using a linear relationship between WTD and CO.sub.2 emissions, we estimated that, averaging over peat hydraulic properties, canal blocks prevented the emission of 1.07 Mg ha.sup.-1 CO.sub.2 in the dry year and 1.17 Mg ha.sup.-1 CO.sub.2 in the wet year. We believe that the modeling tools developed in this work could be adopted by local stakeholders aiming at a more effective and evidence-based approach to canal-block-based peatland restoration.

The carbon (C) dynamics of northern peatlands are sensitive to hydrological changes owing to ecohydrological feedbacks. We quantified and evaluated the impact of water level variations in a beaver pond (BP) on the CO.sub.2 flux dynamics of an adjacent, raised Sphagnum-shrub-dominated bog in southern Canada. We applied the CoupModel to the Mer Bleue bog, where the hydrological, energy and CO.sub.2 fluxes have been measured continuously for over 20 years. The lateral flow of water from the bog to the BP was estimated by the hydraulic gradient between the peatland and the BP's water level and the vertical profile of peat hydraulic conductivity. The model outputs were compared with the measured hydrological components, CO.sub.2 flux and energy flux data (1998-2019). CoupModel was able to reproduce the measured data well. The simulation shows that variation in the BP water level (naturally occurring or due to management) influenced the bog net ecosystem exchange (NEE) of CO.sub.2 . Over 1998-2004, the BP water level was 0.75 to 1.0 m lower than during 2017-2019. Simulated net CO.sub.2 uptake was 55 gCm-2yr-1 lower during 1998-2004 compared to 2017-2019 when there was no BP disturbance, which was similar to the differences in measured NEE between those periods. Peatland annual NEE was well correlated with water table depth (WTD) within the bog, and NEE also shows a linear relation with the water level at the BP, with a slope of -120 gCO2-Cm-2yr-1m-1. The current modelling predicts that the bog may switch from CO.sub.2 sink to source when the BP water levels drop lower than â¼ 1.7 m below the peat surface at the eddy covariance (EC) tower, located on the bog surface 250 m from the BP. This study highlights the importance of natural and human disturbances to adjacent water bodies in regulating the net CO.sub.2 uptake function of northern peatlands.

ABSTRACT Members of the phylum Planctomycetes are common inhabitants of boreal Sphagnum peat bogs and lichen-dominated tundra wetlands. These bacteria colonize both oxic and anoxic peat layers and reach the population size of 107 cells per gram of wet peat. The 16S rRNA gene sequences from planctomycetes comprise 5%–22% of total 16S rRNA gene reads retrieved from peat samples. Most abundant peat-inhabiting planctomycetes affiliate with the families Isosphaeraceae and Gemmataceae, and with as-yet-uncultured Phycisphaera-related group WD2101. The use of metatranscriptomics to assess the functional role of planctomycetes in peatlands suggested the presence of versatile hydrolytic capabilities in these bacteria. This evidence was further confirmed by the analysis of genome-encoded capabilities of isolates from wetlands. Large (up to 12 Mbp) genomes of planctomycetes encode wide repertoires of carbohydrate-active enzymes including many unclassified putative glycoside hydrolases, which suggests the presence of extremely high glycolytic potential in these bacteria. Experimental tests confirmed their ability to grow on xylan, pectin, starch, lichenan, cellulose, chitin and polysaccharides of microbial origin. These results provide an insight into the ecological roles of peat-inhabiting planctomycetes and suggest their participation in degradation of plant-derived polymers, exoskeletons of peat-inhabiting arthropods as well as exopolysaccharides produced by other bacteria. This mini-review summarizes the currently available knowledge on the abundance, phylogenetic diversity, specific adaptations and potential roles of planctomycetes in peatlands.

We investigated recent changes in spatial patterning of fen and bog zones in five boreal aapa mire complexes (mixed peatlands with patterned fen and bog parts) in a multiproxy study. Comparison of old (1940–1970s) and new aerial images revealed decrease of flarks (wet hollows) in patterned fens by 33–63% in middle boreal and 16–42% in northern boreal sites, as lawns of bog Sphagnum mosses expanded over fens. Peat core transects across transformed areas were used to verify the remote sensing inference with stratigraphic analyses of macrofossils, hyperspectral imaging, and age-depth profiles derived from 14C AMS dating and pine pollen density. The transect data revealed that the changes observed by remote sensing during past decades originated already from the end of the Little Ice Age (LIA) between 1700–1850 CE in bog zones and later in the flarks of fen zones. The average lateral expansion rate of bogs over fen zones was 0.77 m y−1 (range 0.19–1.66) as estimated by remote sensing, and 0.71 m y−1 (range 0.13–1.76) based on peat transects. The contemporary plant communities conformed to the macrofossil communities, and distinct vegetation zones were recognized as representing recently changed areas. The fen-bog transition increased the apparent carbon accumulation, but it can potentially threaten fen species and habitats. These observations indicate that rapid lateral bog expansion over aapa mires may be in progress, but more research is needed to reveal if ongoing fen-bog transitions are a commonplace phenomenon in northern mires.

Purpose Aerenchymous plants are an important control for methane efflux from peatlands to the atmosphere, providing a bypass from the anoxic peat and avoiding oxidation in the oxic peat. We aimed to quantify the drivers of aerenchymous peatland species methane transport and the importance of this process for ecosystem-scale methane efflux. Methods We measured seasonal and interspecies variation in methane transport rate per gram of plant dry mass at a boreal fen and bog, which were upscaled to ecosystem-scale plant methane transport. Results Methane transport rate was better explained by plant species, leaf greenness and area than by environmental variables. Leaves appeared to transport methane even after senescence. Contrary to our expectations, both methane transport rate and the proportion of plant transport were lower in the fen (with greater sedge cover) than in the bog site. At the fen and bog, average methane transport rate was 0.7 and 1.8 mg g −1 d −1 , and the proportion of seasonally variable plant transport was 7–41% and 6–90%, respectively. Species-specific differences in methane transport rate were observed at the ecosystem-scale: Scheuchzeria palustris, which accounted for 16% of the aerenchymous leaf area in the fen and displayed the greatest methane transport rate, was responsible for 45% of the ecosystem-scale plant transport. Conclusion Our study showed that plant species influence the magnitude of ecosystem-scale methane emissions through their properties of methane transport. The identification and quantification of these properties could be the pivotal next step in predicting plant methane transport in peatlands.

Over the centuries, anthropogenic pressure has severely impacted peatlands on the European continent. Peatlands cover ~ 21% (1.46 Mha) of Ireland’s land surface, but 85% have been degraded due to management activities (land use). Ireland needs to meet its 2030 climate energy framework targets related to greenhouse gas (GHG) emissions from land use, land use change and forestry, including wetlands. Despite Ireland’s voluntary decision to include peatlands in this system in 2020, information on land use activities and associated GHG emissions from peatlands is lacking. This study strives to fill this information gap by using Landsat (5, 8) data with Google Earth Engine and machine learning to examine and quantify land use on Irish peatlands across three time periods: 1990, 2005 and 2019. Four peatland land use classes were mapped and assessed: industrial peat extraction, forestry, grassland and residual peatland. The overall accuracy of the classification was 86% and 85% for the 2005 and 2019 maps, respectively. The accuracy of the 1990 dataset could not be assessed due to the unavailability of high-resolution reference data. The results indicate that extensive management activities have taken place in peatlands over the past three decades, which may have negative impacts on its ecological integrity and the many ecosystem services provided. By utilising cloud computing, temporal mosaicking and Landsat data, this study developed a robust methodology that overcomes cloud contamination and produces the first peatland land use maps of Ireland with wall-to-wall coverage. This has the potential for regional and global applications, providing maps that could help understand unsustainable management practices on peatlands and the impact on GHG emissions.

Nanhermannia coronata is a common and abundant oribatid species in peatlands, but it can be easily mistaken for N. sellnicki as an adult. The identity of adults of N. coronata investigated herein from several sites in Norway and Ireland was supported by the COI sequence data. Based on this material, the morphological ontogeny of N. coronata was investigated, and some characters were found that clearly differentiate N. coronata from N. sellnicki, like the number of setae on femora of adults and tritonymphs, the shape of insertions of prodorsal seta in and all gastronotal and adanal setae of juveniles. Our ecological observations confirm a common occurrence of N. coronata in raised bogs, a high percentage of juvenile stages in populations and a preference of this species for humid microhabitats, whereas N. sellnicki is less common than N. coronata and occurs in drier habitats. Nanhermannia coronata Berlese, 1913, is a common and abundant oribatid species in peatlands but can be easily mistaken for N. sellnicki Forsslund, 1958, as an adult. Therefore, the identity of adults of N. coronata from several sites in Norway and Ireland was supported by the COI sequence data, and based on this material, the morphological ontogeny of this species is described and illustrated to highlight the differences between N. coronata and N. sellnicki. In all juvenile stages of N. coronata, the bothridial seta is absent, but two pairs of exobothridial setae are present, including short exp and exa reduced to its alveolus. In the larva, seta f[sub.1] is setiform, but in the nymphs, it is reduced to its alveolus. Most prodorsal and gastronotal setae of larva are short, and of nymphs they are long. In all instars, the leg segments are oval in cross section and relatively thick, and many setae on tarsi are relatively short, thick and conical, except for longer apical setae. Seta d accompanies solenidion σ on all genua, φ[sub.1] on tibia I and φ on other tibiae. We found some morphological characters that clearly differentiate N. coronata from N. sellnicki, like the number of setae on femora of adults and tritonymphs, the shape of insertions of prodorsal seta in and all gastronotal and adanal setae of juveniles; in N. sellnicki, these setae are inserted in small individual depressions, whereas in N. coronata, these depressions are absent. Our ecological observations confirm a common occurrence of N. coronata in raised bogs, a high percentage of juvenile stages in its populations and a preference of this species for humid microhabitats, whereas N. sellnicki is less common than N. coronata and occurs in drier habitats.

Coal, coal measure gas, coal conversion to oil and gas, and coal-based new materials are reliable guarantees for stable energy supply and economic and social development in China. The coal-dominated resource endowment and the economic and social development stage determine the irreplaceable position of coal resources in the energy system. Coal measure resources, including aggregated or dispersed solids, liquid and gaseous multitype energies, and metal as well as nonmetallic minerals, are the products of multisphere interaction and metallogenetic materials generation, migration, and accumulation. Coal measures record rich deep-time geological information of transitional and terrestrial peat bogs, which is a crucial carrier to reveal ecosystem evolution, significant organic carbon sequestration, atmospheric O 2 /CO 2 variation, and wildfire events. Coal measure evolution is accompanied by the migration and transformation of various materials during diagenesis-metamorphism, forming differentiated coal compositions besides properties and various mineral resources in its adjacent strata. The enrichment condition, occurrence state, and separation potential are the premise for level-by-level use and efficient development of coal measure resources. Coal measure metallogeny is based on the metallogenic system of multiple energy and mineral resources in coal measures and their environmental effects. Fully understanding coal measure metallogeny is beneficial for promoting the coal transition from fuel to raw materials and strengthening its attribute of multiple mineral resources. The metallogeny comprises various aspects, including: (1) the symbiosis mechanism, co-exploration and co-mining conditions of various resources; (2) the source-sink system of ore-forming materials; (3) the differential carbon accumulation and hydrogen enrichment effect; (4) organic (coal and hydrocarbon) and inorganic (mineral) interactions; and (5) combination of minerals naturally enrichment during the metallogenic process and artificial enrichment during the ore processing process. The coal measure metallogeny belongs to the geoscience disciplines, and study the types, formation, distribution, enrichment mechanisms, evaluation methods, and development strategies of resources related to coal measures. The key scientific problems include geological records related to mineral enrichment processes, metallogenic mechanisms, resource distribution, occurrence evaluation, and accurate development. Developing coal measure metallogeny is significant in improving critical mineral metallogenic theory, revealing various deep-time earth system, and realizing national energy transformation and high-quality development.