Peatland Biogeochemistry

Enzymes are considered to represent valuable biological indicators of ecosystem health. This study evaluates the potential for simultaneous measurement of the activity of multiple enzymes in a single sample. The rate of degradation of a suite of artificial methylumbelliferyl substrates was monitored in a wetland soil sample following separation of the individual components using high pressure liquid chromatography (HPLC). The method allowed effective separation and quantitative monitoring of the hydrolysis of substrates for the enzymes sulfatase, ~-glucosidase, xylosidase, and esterase. The proposed method appeared simple to perform, and offered considerable time-savings over conventional techniques.

Rates of carbon exchange in northern peatlands are dependent on the composition, structure and spatial arrangement of vegetation. Whilst in situ observations can provide detailed information for a given location, remote sensing is the only viable means of collecting land-surface data in a spatially continuous manner across a range of spatial scales. In this paper we review and evaluate many existing and emerging remote sensing approaches used to retrieve peatland land-surface data of relevance to the carbon cycle. We review studies documented in the scientific literature that use remotely sensed data to (i) generate vegetation maps, which may be used to extrapolate field observations, calibrate and extrapolate carbon models and inform peatland management efforts; and (ii) retrieve vegetation biophysical properties, which can be used to parameterize process-based models (e.g. leaf area index (LAI)). There has been considerable progress in the development and implementation of remote sensing approaches that provide data relating to peatland carbon processes. However, there remain a number of methodological challenges, which limit the effectiveness of remote sensing data in some instances. Consequently, we propose that future research approaches focus on (i) continued development, testing and validation of approaches to overcome difficulties caused by the heterogeneous nature of peatland vegetation surfaces (e.g. mixture modeling); (ii) assessment of spatial errors and uncertainty in image classifications, (iii) synergistic use of multiple datasets, (iii) development of scaling algorithms and (iv) continued development of radiative transfer models that can be applied to heterogeneous peatland plant assemblages.

The depositional history of peat-dominated wetlands can be used to understand palaeoclimate and palaeohydrology and also constrain the impacts of future climate change. However, in chalkland valleys, seasonal water table fluctuations and a high alkalinity have diminished key environment indicators such as pollen, and there is a need for alternative investigative techniques. The method of Rock-Eval pyrolysis can track changes in organic matter source and degradation, potentially relating to historic changes in vegetation cover. This is the first Rock-Eval on cores from a groundwater-dependent riparian chalk valley wetland combined with radiocarbon dating. The dating showed that the cores represented approximately 4000 years of depositional history. Changes in hydrocarbon chemistry including normal alkane composition of the peat indicated shifts of around 500 to 1000 years between terrestrial and more aquatic species, relating to periods of climate wetness. These climatic shifts are broadly consistent with other evidence from ombrotrophic peatland and lacustrine sediments across northwest Europe. However, the connection between climate wetness and groundwater dependent chalkland wetlands is complicated by external anthropogenically driven factors relating to land use and vegetation cover changes in the catchment. Nonetheless, this study suggests that Rock-Eval pyrolysis is a useful and cost-effective tool that can provide evidence for long-term Holocene groundwater fluctuations.

Clarification of carbon content characteristics, on their spatial variability in density, of tropical peatlands is needed for more accurate estimates of the C pools and more detailed C cycle understandings. In this study, the C density characteristics of different
peatland types and at various depths within tropical peats in Central Kalimantan were analyzed. The peatland types and the land cover types were classified by land system map and remotely sensed data of multi-temporal AVHRR composites (1-km pixel size), respectively. Differences in the mean values of volumetric C density (CDV) were found among peatland types owing to the variability in physical consolidation from peat decomposition or nutrient inputs, although no vertical trends of CDVwere found. Using a step-wise regression technique, geographic variables and the categories of peatland type and land cover type were found to explain 54% of the variability of CDVwithin tropical peatlands in some conditions.

Hydrology controls the physical, chemical and biological processes in peatlands and hence could be the most important process regulating their function, development and characteristic biogeochemistry. Models describing hydrological processes and soil heat exchange phenomena are an important tool in understanding the peatland biogeochemical cycles of C and N. Presented in this paper is a peat soil climate model that uses weather data, mire site and peat characteristics as input data. The model is related to the heterogeneous peat characteristics (e.g. bulk density, degree of humification, remains of Sphagnum, Carex, Eriophorum and woody tissues), which in turn vary with depth. Evapotranspiration is related to weather parameters and tree stand characteristics. The model simulations were validated against the observed data collected during 1993 and 1994 growing seasons at a fen and bog sites at the Lakkasuo mire complex located in central Finland. The observed and simulated day-to-day variations in water table levels and soil temperatures during both seasons appeared overall to be in phase. As the model lacks the data needed to characterize the peat matrix hysteresis, the model was found lacking in response to wetting and drying cycles. The mean differences between simulated and observed water table levels during 1994 were −0.3 ± 1.3 and −0.5 ± 2.3 cm for the fen and bog sites, respectively. The model was found to be sensitive to mire surface characteristics and evapotranspiration, particularly for the bog site with an unsaturated zone deeper than at the fen. The absolute mean differences between the simulated and measured peat temperatures from 5 to 150 cm were less than 1.0 • C with a maximal standard deviation of 1.6 • C. The model deviations for the upper layers showed larger variations compared to deeper layers, implying a greater accuracy in defining the lower boundary of the thermal regime within the peat column.

Determining the plant traits that best predict carbon (C) storage is increasingly important as global change drivers will affect plant species composition and ecosystem C cycling. Despite the critical role of peatlands in the global C cycle, trait-flux relationships in peatlands are relatively unknown.
We assessed the ability of four non-destructive plant traits to predict carbon dioxide (CO2) and methane (CH4) fluxes over two growing seasons in a temperate peatland in Ontario, Canada. We examined relationships between C-fluxes and leaf area, leaf persistence (deciduous, evergreen), growth form (woody, herbaceous), and aerenchyma tissue. To explore potential inconsistencies between different scales of data aggregation, traits were analysed at the level of plots, species and microsites.
CO2 fluxes showed a positive relationship with leaf area and leaf persistence, and a negative relationship with proportion of woody species. CH4 fluxes showed a positive relationship with aerenchyma and leaf area. The significance of trait-flux relationships differed based on whether data were averaged at the level of plot, species or microsite.
We recommend applying leaf area as a non-destructive trait to other systems where it is not ideal to measure traits destructively. A better understanding of the relationships between above and belowground traits is likely needed to further explain variation in ecosystem respiration and CH4 fluxes from plant traits.

We present a high-resolution (sub-decadal to centennial), multi-proxy reconstruction of aeolian input and
changes in palaeohydrological conditions based on a 13000 Yr record fromNeor Lake's peripheral peat in NW
Iran.Variations inrelative abundancesof refractory (Al,Zr, Ti, andSi), redox sensitive (Fe)andmobile(KandRb)
elements, total organic carbon (TOC), d13CTOC, compound-specific leaf wax hydrogen isotopes (dD), carbon
accumulation rates and dust fluxes presented here fill a large gap in the existing terrestrial paleoclimate records
from the interior of West Asia. Our results suggest that a transition occurred from dry and dusty conditions
during the YoungerDryas (YD) to a relativelywetter periodwith higher carbon accumulation rates and
lowaeolian input during the early Holocene (9000e6000 Yr BP). This period was followed by relatively drier
and dustier conditions during middle to late Holocene,which is consistent with orbital changes in insolation
that affected much of the northern hemisphere. Numerous episodes of high aeolian input spanning a few
decades to millennia are prevalent during the middle to late Holocene. Wavelet analysis of variations in Ti
abundances as a proxy for aeolian input revealed notable periodicities at 230, 320, and 470 years with significant
periodicities centered around 820, 1550, and 3110 years over the last 13000 years. Comparison with
palaeoclimate archives fromWest Asia, theNorth Atlantic andAfrican lakes point to a teleconnection between
NorthAtlantic climate andthe interiorofWest Asiaduring the last glacial terminationandtheHoloceneepoch.
We further assess the potential role of abrupt climate change on early human societies by comparing
our record of palaeoclimate variability with historical, geological and archaeological archives from this
region. The terrestrial record from this study confirms previous evidence from marine sediments of the
Arabian Sea that suggested climate change influenced the termination of the Akkadian empire. In
addition, nearly all observed episodes of enhanced dust deposition during the middle to late Holocene
coincided with times of drought, famine, and power transitions across the Iranian Plateau, Mesopotamia
and the eastern Mediterranean region. These findings indicate that while socio-economic factors are
traditionally considered to shape ancient human societies in this region, the influence of abrupt climate
change should not be underestimated.

In past few years, the use of bacterial calcium carbonate precipitation (biocementation) has
become popular as a ground improvement technique for sandy soil. However, this technique was not applied
to organic soil. This study focused on bacterial calcium carbonate precipitation and its effect on permeability
in organic soil. A special injection system was prepared for inducing bacterial solution to the samples. The
bacterial solution supplied to the samples by gravity for 4 days in specific molds designed for this work.
Calcite precipitation was observed by monitoring pH value and measuring amount of calcium carbonate.
Change in the permeability was measured before and after biocementation. The test results showed that the
pH values indicates that the treatment medium is appropriate for calcite precipitation, and amount of
precipitated calcium carbonate in organic soil increased about 20% from untreated one. It was also found
that the biocementation can be considered as an effective method for reducing permeability of organic soil.
The results were supported by Scanning electron microscopy (SEM) analysis and energy-dispersive x-ray
(EDX) analysis.

Plant-mediated methane (CH 4 ) transport and the contribution of recent photosynthates to methanogenesis were studied on two dominating vascular plant species -Eriophorum vaginatum and Scheuchzeria palustris -at three types of microrelief forms (hummocks -E. hummocks, lawns -E. lawns and hollows -S. hollows) of a boreal natural minerogenic, oligotrophic fen in Eastern Finland. 14 Cpulse labeling of mesocosms with shoots isolated from entire belowground peat under controlled conditions allowed estimation of plant-mediated CH 4 flux and contribution of recent ( 14 C) photosynthates to total CH 4 . The results showed (i) CH 4 flux increased in the order E. hummocks ≤ E. lawns < S. hollows corresponding to the increasing water table level at the relief microforms as adjusted to field conditions. (ii) Plant-mediated CH 4 flux accounted for 38, 31 and 51 % of total CH 4 at E. hummocks, E. lawns and S. hollows, respectively. (iii) Contribution of recent photosynthates to methanogenesis accounted for 0.03 % for E. hummocks, 0.06 % for E. lawns and 0.13 % for S. hollows of assimilated 14 C. Thus, microsites with S. palustris were characterized by higher rates of transported CH 4 from the peat column to the atmosphere when compared to E. vaginatum of drier lawns and hummocks. Contribution of recent photosynthates to methanogenesis was dependent on the plant biomass within-species level (E. vaginatum at hummocks and lawns) but was not observed between species: smaller S. palustris had higher flux of 14 CH 4 as compared to larger E. vaginatum. Therefore, for the assessment of CH 4 dynamics over Correspondence to: M. Dorodnikov ([email protected]) meso-and macroscale as well as for the implication and development of the modeling of CH 4 fluxes, it is necessary to account for plant species-specific differences in CH 4 production, consumption and transport and the attribution of those species to topographic forms of microrelief.

Plant-mediated methane (CH4) transport and the contribution of recent photosynthates to methanogenesis were studied on two dominating vascular plant species – Eriophorum vaginatum and Scheuchzeria palustris – at three types of microrelief forms (hummocks – E. hummocks, lawns – E. lawns and hollows – S. hollows) of a boreal natural minerogenic, oligotrophic fen in Eastern Finland. 14C-pulse labeling of mesocosms with shoots isolated from entire belowground peat under controlled conditions allowed estimation of plant-mediated CH4 flux and contribution of recent (14C) photosynthates to total CH4. The results showed (i) CH4 flux increased in the order E. hummocks ≤ E. lawns < S. hollows corresponding to the increasing water table level at the relief microforms as adjusted to field conditions. (ii) Plant-mediated CH4 flux accounted for 38, 31 and 51 % of total CH4 at E. hummocks, E. lawns and S. hollows, respectively. (iii) Contribution of recent photosynthates to methanogenesis accounted for 0.03 % for E. hummocks, 0.06 % for E. lawns and 0.13 % for S.hollows of assimilated 14C. Thus, microsites with S. palustris were characterized by higher rates of transported CH4 from the peat column to the atmosphere when compared to E. vaginatum of drier lawns and hummocks. Contribution of recent photosynthates to methanogenesis was dependent on the plant biomass within-species level (E. vaginatum at hummocks and lawns) but was not observed between species: smaller S. palustris had higher flux of 14CH4 as compared to larger E. vaginatum. Therefore, for the assessment of CH4 dynamics over meso- and macroscale as well as for the implication and development of the modeling of CH4 fluxes, it is necessary to account for plant species-specific differences in CH4 production, consumption and transport and the attribution of those species to topographic forms of microrelief.

Freshwater wetlands are a major source of the greenhouse gas methane but at the same time can function as carbon sink. Their response to global warming and environmental pollution is one of the largest unknowns in the upcoming decades to centuries. In this review, we highlight the role of sulfate-reducing microorganisms (SRM) in the intertwined element cycles of wetlands. Although regarded primarily as methanogenic environments, biogeochemical studies have revealed a previously hidden sulfur cycle in wetlands that can sustain rapid renewal of the small standing pools of sulfate. Thus, dissimilatory sulfate reduction, which frequently occurs at rates comparable to marine surface sediments, can contribute up to 36–50% to anaerobic carbon mineralization in these ecosystems. Since sulfate reduction is thermodynamically favored relative to fermentative processes and methanogenesis, it effectively decreases gross methane production thereby mitigating the flux of methane to the atmosphere. However, very little is known about wetland SRM. Molecular analyses using dsrAB [encoding subunit A and B of the dissimilatory (bi)sulfite reductase] as marker genes demonstrated that members of novel phylogenetic lineages, which are unrelated to recognized SRM, dominate dsrAB richness and, if tested, are also abundant among the dsrAB-containing wetland microbiota. These discoveries point toward the existence of so far unknown SRM that are an important part of the autochthonous wetland microbiota. In addition to these numerically dominant microorganisms, a recent stable isotope probing study of SRM in a German peatland indicated that rare biosphere members might be highly active in situ and have a considerable stake in wetland sulfate reduction. The hidden sulfur cycle in wetlands and the fact that wetland SRM are not well represented by described SRM species explains their so far neglected role as important actors in carbon cycling and climate change.

In this study, we combine erosion and anthropogenic proxies (Ti, Pb) from calibrated portable XRF with pollen and radiocarbon chronologies in peat from mires of the Kleinwalser Valley (Kleinwalsertal, Vorarlberg, Austria) to reconstruct palaeoenvironmental change and human impact in the northern central Alps. Favoured by a wetter climate, two analysed mires formed 6200 years ago in a densely forested valley. Landscape opening suggests that the first anthropogenic impact emerged around 5700 to 5300 cal BP. Contemporaneously, lead enrichment factors (Pb EFs) indicate metallurgical activities, predating the earliest archaeological evidence in the region. Pollen and erosion proxies show that large-scale deforestation and land use by agro-pastoralists took place from the mid-to late Bronze Age (3500 to 2800 cal BP). This period was directly followed by a prominent peak in Pb EF, pointing to metallurgical activities again. After 200 cal CE, a rising human impact was interrupted by climatic deteriorations in the first half of the 6th century CE, probably linked to the Late Antique Little Ice Age. The use of the characteristic Pb EF pattern of modern pollution as a time marker allows us to draw conclusions about the last centuries. These saw the influence of the Walser people, arriving in the valley after 1300 cal CE. Later, the beginning of tourism is reflected in increased erosion signals after 1950 cal CE. Our study demonstrates that prehistoric humans were intensively shaping the Kleinwalser Valley's landscape, well before the arrival of the Walser people. It also demonstrates the importance of palaeoenvironmental multiproxy studies to fill knowledge gaps where archaeological evidence is lacking. Kurzfassung: In dieser Studie kombinieren wir Paläoproxies für Erosion und menschliche Aktivitäten (Ti, Pb) aus Messungen eines mobilen RFA-bzw. XRF-Analysators mit Pollen und Radiokohlenstoffdatierungen in Torfproben aus Mooren des Kleinwalsertals (Vorarlberg, Österreich). Auf diese Weise sollen der Wandel der Paläoumweltbedingungen sowie der Einfluss des Menschen auf die Landschaft der nördlichen Zentralalpen untersucht werden. Begünstigt durch feuchteres Klima, begann vor ca. 6200 Jahren im damals dicht bewaldeten Tal die Torfbildung in zwei der untersuchten Moore. Au-Published by Copernicus Publications on behalf of the Deutsche Quartärvereinigung (DEUQUA) e.V. 14 C. von Scheffer et al.: 6200 years of human impact (northern central Alps) flichtungen des Waldes deuten auf den ersten menschlichen Einfluss zwischen cal B.P. 5700 und 5300 hin. Gleichzeitig suggerieren Bleianreicherungen (Pb EF) metallurgische Aktivitäten, die weit vor jeglichen archäologischen Beweisen in der Region liegen. Pollen und Erosionsproxies bezeugen eine weitläufige Entwaldung und Landnutzung durch Landwirtschaft und Beweidung in der mittleren und späten Bronzezeit (3500 bis 2800 cal B.P.). Dieser Phase folgte ein vorläufiger Höchstwert des Pb EF zum Beginn der Eisenzeit, der erneut auf Bergbau oder Metallurgie in der näheren Umgebung hindeutet. Eine im cal A.D. 3. Jahrhundert einsetzende verstärkte Landnutzung wird im cal A.D. 6. Jahrhundert unvermittelt durch klimatisch ungünstigere Bedingungen unterbrochen, welche der sogenannten spätantiken kleinen Eiszeit zugeschrieben werden können. Unter Zuhilfenahme des charakteristischen Verlaufs der modernen Bleiemissionen als Zeitmarker, konnten die Analyseergebnisse der letzten Jahrhunderte eingeordnet werden. Diese waren von der Ansiedlung der Walser im cal A.D. 14. Jahrhundert geprägt. Nach cal A.D. 1950 zeigt sich außerdem der erstarkende Tourismus anhand höherer Erosionsspuren. Unsere Ergebnisse machen deutlich, dass die Landschaft des Kleinwalsertals schon weit vor Ankunft der Walser vom Menschen genutzt und verändert wurde. Unsere Studie betont zudem die Wichtigkeit der Anwendung unterschiedlicher Paläoproxies, insbesondere, wenn archäologische Anhaltspunkte zur Landnutzungsgeschichte fehlen.

The mineralogical composition of a 40 cm subsurface layer of transitional mire 'Bagno Bruch' (southern Poland) polluted with atmospheric dust was studied using scanning electron microscopy. The mire is located 9 km to the east of a zinc smelter on the northern limit of industrial Upper Silesia in southern Poland. Concentrations of zinc, lead and cadmium reach values of 494, 238 and 16 mg kg −1 , respectively, in the peat layer. Inorganic particles in the peat were grouped into two main categories based on their origin: air dust particles of anthropogenic-and natural sources, and authigenic minerals that originated within the mire. Anthropogenic particles comprise an important part of the inorganic particles in the peat. As they are typically enriched in heavy metals, their stability is critical to controlling metal mobilities. Spheroidal aluminosilicate fly-ash particles are the most common-and most stable anthropogenic pollutants. Partially dissolved Pb-bearing particles (sulphides, chlorides and oxides) and ZnS occur as trace components throughout the peat profile. The prolonged existence of the particles made them susceptible to gravitational relocation in the peat and limits the biogeochemical cycling of the constituent elements. The least resistant Fe (hydro)oxides release Zn and minor amounts of Mn, Mg and Sn due to reductive dissolution. The released Zn is immobilized in the form of ZnS spherules, 1–3 μm in diameter, approximately 10 cm further down in the profile. The investigation shows that the behaviour of trace elements in polluted peatland is controlled by mineral dissolution/precipitation processes. The formation of authigenic minerals (ZnS, barite, gypsum) indicates complex redox conditions and element redistribution in the transitional mire.

Ombrotrophic bogs in southern Patagonia have been examined with regard to paleoclimatic and geochemical research questions but knowledge about organic matter decomposition in these bogs is limited. Therefore, we examined peat humification with depth by Fourier Transformed Infrared (FTIR) measurements of solid peat, C/N ratio, and δ13C and δ15N isotope measurements in three bog sites. Peat decomposition generally increased with depth but distinct small scale variation probably caused by environmental changes occurred. C/N ratios varied mostly between 40 and 120 and were significantly correlated (R2 > 0.55, p < 0.01) with FTIR-derived humification indices. The degree of decomposition was lowest at the site with the least sea spray input, while the peat was most decomposed at the driest site with highest sea spray deposition. Decomposition of peat was also advanced near ash layers. Values of δ13C were 26.5 ± 2‰ in the peat and partly related to decomposition indices, while δ15N in the peat varied around zero and did not consistently relate to any decomposition index. Concentrations of DOM partly related to C/N ratios, partly to FTIR derived indices. DOM was enriched in 13C and in 15N relative to the solid phase probably due to multiple microbial modifications and recycling of N in these N-poor environments. In summary, paleoclimatic signals may have influenced decomposition according to depth profiles of C/N ratios, δ13C values, and FTIR spectra, but the study also suggests that decomposition was also influenced by ash layers, sea spray input and other site specific factors.

Small-sized ferruginous micronodules or pisolith nodules, frequently occurring in inland freshwater systems in moderate climate zones, are important indicators of groundwater level changes and early diagenetic processes, especially within the Pleistocene post-glacial sedimentary systems, including swamps, peatbogs, rivers, or lakes. Compared to the other geochemical environments, pisolith nodules are usually dominated by iron hydroxides and oxides. In most cases, described micronodules indicate high phosphatization, significant contribution of allogenic detrital components, and low manganese content. The major aim of the article is to present textural, geochemical, and mineralogical variability of pisolith nodules recovered from the Roztoka Odrzańska, Odra river mouth area, NW Poland. We describe genetical relations between different types of pisoliths and try to interpret the possible formation phenomena. Analyzed loose ferruginous micronodules were separated from the lacustrine silty-clayey sapropel muds and gyttja, later analyzed using optical microscopy, SEM-energy dispersive x-ray (EDX), and XRD methods. As a reference material, we use archival iron bog ores and geochemical data of different types of nodules. Additionally, we describe previously unknown siderite-rich nodules found in neighboring sites of the Dąbie Lake and the Szczecin Lagoon.

Pseudomorphs of barite (BaSO 4) and Cd-rich ZnS after whewellite (CaC 2 O 4 ·H 2 O) occur within remnants of Scots pine bark tissues in the peat layer of a poor fen located near a zinc smelter in south Poland. A two-step formation of the pseudomorphs is postulated based on SEM observations: (1) complete dissolution of whewellite, possibly caused by oxalotrophic bacteria, and (2) subsequent bacterially induced precipitation of barite and spheroidal aggregates of ZnS together with galena (PbS) in voids left by the dissolved whewellite crystals. Local increase in pH due to microbial degradation of whewellite, elevated concentrations of Zn(II) and Ba(II) in pore water due to the decomposition of atmospheric particles of sphalerite and barite in the acidic (pH 3.5– 3.8) environment, oxidation of S species during drying and rewetting of the peat layer, and subsequent partial reduction of sulfate anions by sulfur-reducing bacteria were all factors likely involved in the crystallization of ZnS and barite in the microenvironment of the post-whewellite voids.

The large accumulation of carbon in peatlands arises from slow organic matter decomposition where microorganisms and their enzyme activities play a critical role. However, there is a dearth of studies on the natural patterns of peatland microbial enzyme activity and inhibitory phenolic compounds over seasons, and across a range of depths and biogeochemically different peatland types. We report the spatiotemporal patterns for phenol oxidases, phenolics, and a suite of five key hydrolase enzymes at two depths in two ombrotrophic bogs, mineral poor and rich fens, and a forested basin swamp over the growing season. Results obtained using linear fixed and mixed effect models suggest that phenol oxidase activity varies significantly with temperature and, to a lesser extent pH, leading to a breakdown of inhibitory phenolics and increased hydrolase enzyme activity across all peatland types. Overall, enzyme activity decreased significantly with depth and showed significant variation over the course of the growing season with a minimum in the spring and a maximum in the summer and fall. Enzyme activities were generally greatest in the rich fen and lowest in the forested basin swamp with no significant difference between bogs and poor fens. Site-specific factors such as nutrient availability explain deviations from these patterns. Our results illustrate the widespread but conditional applicability of the enzyme-latch mechanism to peatlands and the vulnerability of the peatland soil organic carbon stock to climate warming.

We present a high-resolution (sub-decadal to centennial), multi-proxy reconstruction of aeolian input and changes in palaeohydrological conditions based on a 13000 Yr record fromNeor Lake&#39;s peripheral peat in NW Iran.Variations inrelative abundancesof refractory (Al,Zr, Ti, andSi), redox sensitive (Fe)andmobile(KandRb) elements, total organic carbon (TOC), d13CTOC, compound-specific leaf wax hydrogen isotopes (dD), carbon accumulation rates and dust fluxes presented here fill a large gap in the existing terrestrial paleoclimate records from the interior of West Asia. Our results suggest that a transition occurred from dry and dusty conditions during the YoungerDryas (YD) to a relativelywetter periodwith higher carbon accumulation rates and lowaeolian input during the early Holocene (9000e6000 Yr BP). This period was followed by relatively drier and dustier conditions during middle to late Holocene,which is consistent with orbital changes in insolation that affected much of the n...

Human civilizations around the globe have been influenced by abrupt climate change throughout the Holocene. The paucity of high-resolution palaeoclimate data from the "Cradle of Civilization" in West Asia, however, has limited our ability to evaluate the potential role of Holocene climate variability on early societies. We present a high-resolution, multi-proxy reconstruction of aeolian input and palaeoenvironmental conditions based on a 13-kyr record of ombrotrophic (rain fed) peat from Neor Lake in Northwest Iran. Variations in relative abundances of major and trace elements, total organic carbon (TOC), stable carbon isotopes of TOC (δ 13 C TOC ) and compound-specific leaf wax hydrogen isotope (δD) compositions suggest dry and dusty conditions prevailed during the Younger Dryas, and a substantial increase in atmospheric dust loading and decrease in moisture availability occurred between the early and late Holocene. In addition, variations in radiogenic Sr-Nd-Hf isotopic composition and REE anomalies in samples from Neor peat core indicate significant shifts occurred in source contributions of eolian material to the study area between the Younger Dryas, early and late Holocene. Time-series analysis of aeolian input to NE Iran reveals periodicities at 540, 1050 and 2940 years that correspond with solar variability and internal climate feedbacks identified in other records of Holocene climate change from the northern hemisphere. Transitions in major Mesopotamian and Persian civilizations, including the collapse of the Akkadian empire at 4,200 yr BP, the fall of the Ur III empire at 3,955 yr BP, the fall of Elam empire at 2,500 yr BP and the demise of the Achaemenids around 2,280 BP overlap with major dust events from this study. Several other episodes of enhanced atmospheric dust, however, are not reflected in historical or archaeological accounts of the late Holocene. This indicates either abrupt climate change was not the sole driver of societal changes in the region, or that historical records of these events are incomplete.

There is a need for coordinated research for the sustainable management of tropical peatland. Malaysia has 6% of global tropical peat by area and peatlands there are subject to land use change at an unprecedented rate. This paper describes a stakeholder engagement exercise that identified 95 priority research questions for peatland in Malaysia, organized into nine themes. Analysis revealed the need for fundamental scientific research, with strong representation across the themes of environmental change, ecosystem services, and conversion, disturbance and degradation. Considerable uncertainty remains about Malaysia's baseline conditions for peatland, including questions over total remaining area of peatland, water table depths, soil characteristics, hydrological function, biogeochemical processes and ecology. More applied and multidisciplinary studies involving researchers from the social sciences are required. The future sustainability of Malaysian peatland relies on coordinating research agendas via a 'knowledge hub' of researchers, strengthening the role of peatlands in land-use planning and development processes, stricter policy enforcement, and bridging the divide between national and provincial governance. Integration of the economic value of peatlands into existing planning regimes is also a stakeholder priority. Finally, current research needs to be better communicated for the benefit of the research community, for improved societal understanding and to inform policy processes.

SUMMARYThere is a need for coordinated research for the sustainable management of tropical peatland. Malaysia has 6% of global tropical peat by area and peatlands there are subject to land use change at an unprecedented rate. This paper describes a stakeholder engagement exercise that identified 95 priority research questions for peatland in Malaysia, organized into nine themes. Analysis revealed the need for fundamental scientific research, with strong representation across the themes of environmental change, ecosystem services, and conversion, disturbance and degradation. Considerable uncertainty remains about Malaysia&#39;s baseline conditions for peatland, including questions over total remaining area of peatland, water table depths, soil characteristics, hydrological function, biogeochemical processes and ecology. More applied and multidisciplinary studies involving researchers from the social sciences are required. The future sustainability of Malaysian peatland relies on coor...

and his staff at the Chico Basin Ranch for allowing us access to the fens at the ranch, and John B. Gilmore for providing laboratory and financial assistance. Mark Chenault and his family deserve our appreciation for providing room and board to Kevin Gilmore while he was processing samples at the Arizona ams Facility. Several people provided comments that greatly improved the ideas and presentation of this field note. We would like to thank Kay Wall at ero Resources for technical editing and Craig E. Colten at the Geographical Review, Max Canestorp, and two anonymous reviewers for their constructive comments on our manuscript. As always, we take full responsibility for any errors and omissions.

In past few years, the use of bacterial calcium carbonate precipitation (biocementation) has become popular as a ground improvement technique for sandy soil. However, this technique was not applied to organic soil. This study focused on bacterial calcium carbonate precipitation and its effect on permeability in organic soil. A special injection system was prepared for inducing bacterial solution to the samples. The bacterial solution supplied to the samples by gravity for 4 days in specific molds designed for this work. Calcite precipitation was observed by monitoring pH value and measuring amount of calcium carbonate. Change in the permeability was measured before and after biocementation. The test results showed that the pH values indicates that the treatment medium is appropriate for calcite precipitation, and amount of precipitated calcium carbonate in organic soil increased about 20% from untreated one. It was also found that the biocementation can be considered as an effective method for reducing permeability of organic soil. The results were supported by Scanning electron microscopy (SEM) analysis and energy-dispersive x-ray (EDX) analysis.

We present a high-resolution (sub-decadal to centennial), multi-proxy reconstruction of aeolian input and changes in palaeohydrological conditions based on a 13,000 yr record from Neor Lake's peripheral peat in NW Iran. Variations in relative abundances of refractory (Al, Zr, Ti, and Si), redox sensitive (Fe) and mobile (K and Rb) elements, total organic carbon (TOC), δ 13 C TOC , compound-specific leaf wax hydrogen isotopes (δD), carbon accumulation rates and dust fluxes presented here fill a large gap in the existing terrestrial paleoclimate records from the interior of West Asia. Our results suggest that a transition occurred from dry and dusty conditions during the Younger Dryas (YD) to a relatively wetter period with higher carbon accumulation rates and low aeolian input during the early Holocene (9,000-6000 yr BP). This period was followed by relatively drier and dustier conditions during middle to late Holocene, which is consistent with orbital changes in insolation that affected much of the northern hemisphere. Numerous episodes of high aeolian input spanning a few decades to millennia are prevalent during the middle to late Holocene. Wavelet analysis of variations in Ti abundances as a proxy for aeolian input revealed notable periodicities at 230, 320, and 470 years with significant periodicities centered around 820, 1,550, and 3,110 years over the last 13,000 years. Comparison with palaeoclimate archives from West Asia, the North Atlantic and African lakes point to a teleconnection between North Atlantic climate and the interior of West Asia during the last glacial termination and the Holocene epoch. We further assessed the potential role of abrupt climate change on early human societies by comparing our record of palaeoclimate variability with historical, geological and archaeological archives from this region. The terrestrial record from this study confirms previous evidence from marine sediments of the Arabian Sea that suggested climate change influenced the 3 termination of the Akkadian empire. In addition, nearly all observed episodes of enhanced dust deposition during the middle to late Holocene coincided with times of drought, famine, and power transitions across the Iranian Plateau, Mesopotamia and the eastern Mediterranean region. These findings indicate that while socioeconomic factors are traditionally considered to shape ancient human societies in this region, the influence of abrupt climate change should not be underestimated.

We present a high-resolution (sub-decadal to centennial), multi-proxy reconstruction of aeolian input and changes in palaeohydrological conditions based on a 13000 Yr record fromNeor Lake&#39;s peripheral peat in NW Iran.Variations inrelative abundancesof refractory (Al,Zr, Ti, andSi), redox sensitive (Fe)andmobile(KandRb) elements, total organic carbon (TOC), d13CTOC, compound-specific leaf wax hydrogen isotopes (dD), carbon accumulation rates and dust fluxes presented here fill a large gap in the existing terrestrial paleoclimate records from the interior of West Asia. Our results suggest that a transition occurred from dry and dusty conditions during the YoungerDryas (YD) to a relativelywetter periodwith higher carbon accumulation rates and lowaeolian input during the early Holocene (9000e6000 Yr BP). This period was followed by relatively drier and dustier conditions during middle to late Holocene,which is consistent with orbital changes in insolation that affected much of the n...

We present a high-resolution (sub-decadal to centennial), multi-proxy reconstruction of aeolian input and changes in palaeohydrological conditions based on a 13,000 yr record from Neor Lake's peripheral peat in NW Iran. Variations in relative abundances of refractory (Al, Zr, Ti, and Si), redox sensitive (Fe) and mobile (K and Rb) elements, total organic carbon (TOC), δ 13 C TOC , compound-specific leaf wax hydrogen isotopes (δD), carbon accumulation rates and dust fluxes presented here fill a large gap in the existing terrestrial paleoclimate records from the interior of West Asia. Our results suggest that a transition occurred from dry and dusty conditions during the Younger Dryas (YD) to a relatively wetter period with higher carbon accumulation rates and low aeolian input during the early Holocene (9,000-6000 yr BP). This period was followed by relatively drier and dustier conditions during middle to late Holocene, which is consistent with orbital changes in insolation that affected much of the northern hemisphere. Numerous episodes of high aeolian input spanning a few decades to millennia are prevalent during the middle to late Holocene. Wavelet analysis of variations in Ti abundances as a proxy for aeolian input revealed notable periodicities at 230, 320, and 470 years with significant periodicities centered around 820, 1,550, and 3,110 years over the last 13,000 years. Comparison with palaeoclimate archives from West Asia, the North Atlantic and African lakes point to a teleconnection between North Atlantic climate and the interior of West Asia during the last glacial termination and the Holocene epoch. We further assessed the potential role of abrupt climate change on early human societies by comparing our record of palaeoclimate variability with historical, geological and archaeological archives from this region. The terrestrial record from this study confirms previous evidence from marine sediments of the Arabian Sea that suggested climate change influenced the 3 termination of the Akkadian empire. In addition, nearly all observed episodes of enhanced dust deposition during the middle to late Holocene coincided with times of drought, famine, and power transitions across the Iranian Plateau, Mesopotamia and the eastern Mediterranean region. These findings indicate that while socioeconomic factors are traditionally considered to shape ancient human societies in this region, the influence of abrupt climate change should not be underestimated.

SUMMARYThere is a need for coordinated research for the sustainable management of tropical peatland. Malaysia has 6% of global tropical peat by area and peatlands there are subject to land use change at an unprecedented rate. This paper describes a stakeholder engagement exercise that identified 95 priority research questions for peatland in Malaysia, organized into nine themes. Analysis revealed the need for fundamental scientific research, with strong representation across the themes of environmental change, ecosystem services, and conversion, disturbance and degradation. Considerable uncertainty remains about Malaysia&#39;s baseline conditions for peatland, including questions over total remaining area of peatland, water table depths, soil characteristics, hydrological function, biogeochemical processes and ecology. More applied and multidisciplinary studies involving researchers from the social sciences are required. The future sustainability of Malaysian peatland relies on coor...

Deposit-Signet, Archivserver deposit.d-nb.de. Logo DDB. Autor : Knorr, Klaus-Holger. Titel : Dynamics of soil processes under extreme meteorological boundary conditions : response of below-ground carbon, sulfur, and iron cycling in fen soils. ...

The Florisbad spring site has produced a large collection of fossil bones dating to the Middle Pleistocene and several assemblages of Middle Stone Age (MSA) artifacts. The species featured in the faunal collection define the Florisian Land Mammal Age, characterized mainly by grazing ungulates that reflect an open grassland environment. Early MSA artifacts found within the basal layers represent the earliest evidence of human presence at Florisbad, followed by an intact MSA occupation horizon characterized by stone tools and animal bones, in direct association and primary context. These fossils and artifacts were found embedded within sand and peat layers. Previous studies investigated the genesis of such deposits using field descriptions and bulk sedimentological analyses. However, sediments were never studied within their original context, thus leading to difficulties in determining the formation processes of the deposits. Using a multi-analytical micro-geoarchaeological approach including sediment micromorphology, FTIR and XRD, we were able to show that the site is characterized by alternating aeolian sand layers reworked by lacustrine water during the wet phases of the Pleistocene, and peat layers formed in marshes during dry phases. The results confirm most of the previous paleoenvironmental reconstructions and provide a refined stratigraphic sequence of the site.

Peatlands support vital ecosystem services such as water regulation, specific habitat provisions and carbon storage. In Canada, anthropogenic disturbance from energy exploration has undermined the capacity of peatlands to support these vital ecosystem services, and thus presents the need for their reclamation to a functional ecosystem. As attempts are now being made to implement reclamation plans on post-mining oil sands landscapes, a major challenge remains in the absence of a standard framework for evaluating the functional state of a constructed peatland. To address this challenge, we present a functional-based approach that can guide the evaluation of constructed peatlands in the Alberta oil sands region. We achieved this by conducting a brief review, which synthesized the dominant processes of peatland functional development in natural analogues. Through the synthesis, we identified the interaction and feedback processes that under-line various peatland ecosystem functions and their quantifiable variables. By exploring the mechanism of key ecosystem interactions, we highlighted the sensitivity of microbially mediated biogeochemical processes to a range of variability in other ecosystem functions, and thus the appropriateness of using them as functional indicators of ecosystem condition. Following the verification of this concept through current pilot fen reclamation projects, we advocate the need for further research towards modification to a more cost-efficient approach that can be applicable to large-scale fen reclamation projects in this region.

Deposit-Signet, Archivserver deposit.d-nb.de. Logo DDB. Autor : Knorr, Klaus-Holger. Titel : Dynamics of soil processes under extreme meteorological boundary conditions : response of below-ground carbon, sulfur, and iron cycling in fen soils. ...

Carbon flux models that are largely driven by remotely sensed data can be used to estimate gross primary productivity (GPP) over large areas, but despite the importance of peatland ecosystems in the global carbon cycle, relatively little attention has been given to determining their success in these ecosystems. This paper is the first to explore the potential of chlorophyll-based VI models for estimating peatland GPP from satellite data. Using several years of carbon flux data from contrasting peatlands, we explored the relationships between the MERIS Terrestrial Chlorophyll Index (MTCI) and GPP, and determined whether the inclusion of environmental variables such as PAR and temperature, thought to be important determinants of peatland carbon flux, improved upon direct relationships. To place our results in context, we compared the newly developed GPP models with the MODIS (Moderate Resolution Imaging Spectrometer) GPP product. Our results show that simple MTCI-based models can be used for estimates of inter- and intra annual variability in peatland GPP. The MTCI is a good indicator of GPP and compares favourably with more complex products derived from the MODIS sensor on a site specific basis. The incorporation of MTCI into a light use efficiency type model, by means of partitioning the fraction of photosynthetic material within a plant canopy, shows most promise for peatland GPP estimation, outperforming all other models. Our results show great promise and demonstrate that satellite data specifically related to vegetation chlorophyll content, may ultimately facilitate improved quantification of peatland carbon flux dynamics.