Articles | Volume 11, issue 12
24 Jun 2014
Research article | 24 Jun 2014
Degradation changes stable carbon isotope depth profiles in palsa peatlands
J. P. Krüger et al.
J. P. Krüger, J. Leifeld, S. Glatzel, S. Szidat, and C. Alewell
Biogeosciences, 12, 2861–2871,Short summary
Biogeochemical soil parameters are studied to detect peatland degradation along a land use gradient (intensive, extensive, near-natural). Stable carbon isotopes, radiocarbon ages and ash content confirm peat growth in the near-natural bog but also indicate previous degradation. When the bog is managed extensively or intensively as grassland, all parameters indicate degradation and substantial C loss of the order of 18.8 to 42.9 kg C m-2.
Pedro V. G. Batista, Peter Fiener, Simon Scheper, and Christine Alewell
Hydrol. Earth Syst. Sci., 26, 3753–3770,Short summary
Patchy agricultural landscapes have a large number of small fields, which are separated by linear features such as roads and field borders. When eroded sediments are transported out of the agricultural fields by surface runoff, these features can influence sediment connectivity. By use of measured data and a simulation model, we demonstrate how a dense road network (and its drainage system) facilitates sediment transport from fields to water courses in a patchy Swiss agricultural catchment.
Brieuc Hardy, Nils Borchard, and Jens Leifeld
SOIL, 8, 451–466,Short summary
Soil amendment with artificial black carbon (BC; biomass transformed by incomplete combustion) has the potential to mitigate climate change. Nevertheless, the accurate quantification of BC in soil remains a critical issue. Here, we successfully used dynamic thermal analysis (DTA) to quantify centennial BC in soil. We demonstrate that DTA is largely under-exploited despite providing rapid and low-cost quantitative information over the range of soil organic matter.
Lena Wohlgemuth, Pasi Rautio, Bernd Ahrends, Alexander Russ, Lars Vesterdal, Peter Waldner, Volkmar Timmermann, Nadine Eickenscheidt, Alfred Fürst, Martin Greve, Peter Roskams, Anne Thimonier, Manuel Nicolas, Anna Kowalska, Morten Ingerslev, Päivi Merilä, Sue Benham, Carmen Iacoban, Günter Hoch, Christine Alewell, and Martin Jiskra
Biogeosciences, 19, 1335–1353,Short summary
Gaseous mercury is present in the atmosphere all over the globe. During the growing season, plants take up mercury from the air in a similar way as CO2. We investigated which factors impact this vegetational mercury uptake by analyzing a large dataset of leaf mercury uptake rates of trees in Europe. As a result, we conclude that mercury uptake is foremost controlled by tree-intrinsic traits like physiological activity but also by climatic factors like dry conditions in the air and in soils.
Lauren Zweifel, Maxim Samarin, Katrin Meusburger, and Christine Alewell
Nat. Hazards Earth Syst. Sci., 21, 3421–3437,Short summary
Mountainous grassland areas can be severely affected by soil erosion, such as by shallow landslides. With an automated mapping approach we are able to locate shallow-landslide sites on aerial images for 10 different study sites across Swiss mountain regions covering a total of 315 km2. Using a statistical model we identify important explanatory variables for shallow-landslide occurrence for the individual sites as well as across all regions, which highlight slope, aspect and terrain roughness.
Maral Khodadadi, Christine Alewell, Mohammad Mirzaei, Ehssan Ehssan-Malahat, Farrokh Asadzadeh, Peter Strauss, and Katrin Meusburger
Revised manuscript not acceptedShort summary
Forest soils store carbon and therefore play an important role in mitigating climate change impacts. Yet again, deforestation for farming and grazing purposes has grown rapidly over the last decades. Thus, its impacts on soil erosion and soil quality should be understood in order to adopt sustainable management measures. The results of this study indicated that deforestation can prompt soil loss by multiple orders of magnitude and deteriorate the soil quality in both topsoil and subsoil.
Claudia Mignani, Jörg Wieder, Michael A. Sprenger, Zamin A. Kanji, Jan Henneberger, Christine Alewell, and Franz Conen
Atmos. Chem. Phys., 21, 657–664,Short summary
Most precipitation above land starts with ice in clouds. It is promoted by extremely rare particles. Some ice-nucleating particles (INPs) cause cloud droplets to already freeze above −15°C, a temperature at which many clouds begin to snow. We found that the abundance of such INPs among other particles of similar size is highest in precipitating air masses and lowest when air carries desert dust. This brings us closer to understanding the interactions between land, clouds, and precipitation.
Lena Wohlgemuth, Stefan Osterwalder, Carl Joseph, Ansgar Kahmen, Günter Hoch, Christine Alewell, and Martin Jiskra
Biogeosciences, 17, 6441–6456,Short summary
Mercury uptake by trees from the air represents an important but poorly quantified pathway in the global mercury cycle. We determined mercury uptake fluxes by leaves and needles at 10 European forests which were 4 times larger than mercury deposition via rainfall. The amount of mercury taken up by leaves and needles depends on their age and growing height on the tree. Scaling up our measurements to the forest area of Europe, we estimate that each year 20 t of mercury is taken up by trees.
Miriam Groß-Schmölders, Pascal von Sengbusch, Jan Paul Krüger, Kristy Klein, Axel Birkholz, Jens Leifeld, and Christine Alewell
SOIL, 6, 299–313,Short summary
Degradation turns peatlands into a source of CO2. There is no cost- or time-efficient method available for indicating peatland hydrology or the success of restoration. We found that 15N values have a clear link to microbial communities and degradation. We identified trends in natural, drained and rewetted conditions and concluded that 15N depth profiles can act as a reliable and efficient tool for obtaining information on current hydrology, restoration success and drainage history.
Pranav Hirave, Guido L. B. Wiesenberg, Axel Birkholz, and Christine Alewell
Biogeosciences, 17, 2169–2180,Short summary
Sediment input into water bodies is a prominent threat to freshwater ecosystems. We tested the stability of tracers employed in freshwater sediment tracing based on compound-specific isotope analysis during early degradation in soil. While bulk δ13C values showed no stability, δ13C values of plant-derived fatty acids and n-alkanes were stably transferred to the soil without soil particle size dependency after an early degradation in organic horizons, thus indicating their suitability as tracers.
Marlène Lavrieux, Axel Birkholz, Katrin Meusburger, Guido L. B. Wiesenberg, Adrian Gilli, Christian Stamm, and Christine Alewell
Biogeosciences, 16, 2131–2146,Short summary
A fingerprinting approach using compound-specific stable isotopes was applied to a lake sediment core to reconstruct erosion processes over the past 150 years in a Swiss catchment. Even though the reconstruction of land use and eutrophication history was successful, the observation of comparatively low δ13C values of plant-derived fatty acids in the sediment suggests their alteration within the lake. Thus, their use as a tool for source attribution in sediment cores needs further investigation.
Claudia Mignani, Jessie M. Creamean, Lukas Zimmermann, Christine Alewell, and Franz Conen
Atmos. Chem. Phys., 19, 877–886,Short summary
A snow crystal can be generated from an ice nucleating particle or from an ice splinter. In this study we made use of the fact that snow crystals with a particular shape (dendrites) grow within a narrow temperature range (−12 to −17 °C) and can be analysed individually for the presence of an ice nucleating particle. Our direct approach revealed that only one in eight crystals contained such a particle and was of primary origin. The other crystals must have grown from ice splinters.
Cédric Bader, Moritz Müller, Rainer Schulin, and Jens Leifeld
Biogeosciences, 15, 703–719,Short summary
When drained, peatlands degrade and release large quantities of CO2, thereby contributing to global warming. Do land use or the chemical composition of peat control the rate of that release? We studied 21 sites from the temperate climate zone managed as croplands, grasslands, or forests and found that the CO2 release was high, but only slightly influenced by land use or peat composition. Hence, only keeping peatlands in their natural state prevents them from becoming strong CO2 sources.
Laura Arata, Katrin Meusburger, Alexandra Bürge, Markus Zehringer, Michael E. Ketterer, Lionel Mabit, and Christine Alewell
SOIL, 3, 113–122,
Emiliano Stopelli, Franz Conen, Caroline Guilbaud, Jakob Zopfi, Christine Alewell, and Cindy E. Morris
Biogeosciences, 14, 1189–1196,Short summary
Based on the analysis of precipitation collected at high altitude, this study provides a relevant advancement in the assessment of the major factors responsible for the abundance and variability of airborne bacterial cells and Pseudomonas syringae in relation to ice nucleators. This is of prime importance to obtain a better understanding of the impact of ice-nucleation-active organisms on the development of precipitation and to determine the dispersal potential of airborne microorganisms.
Simon Schmidt, Christine Alewell, Panos Panagos, and Katrin Meusburger
Hydrol. Earth Syst. Sci., 20, 4359–4373,Short summary
We present novel research on the seasonal dynamics of the impact of rainfall (R-factor) on the mobilization of topsoil as soil erosion by water for Switzerland. A modeling approach was chosen that enables the dynamical mapping of the R-factor. Based on the maps and modeling results, we could investigate the spatial and temporal distribution of that factor, which is high for Switzerland. With these results, agronomists can introduce selective erosion control measures.
Emiliano Stopelli, Franz Conen, Cindy E. Morris, Erik Herrmann, Stephan Henne, Martin Steinbacher, and Christine Alewell
Atmos. Chem. Phys., 16, 8341–8351,Short summary
Knowing the variability of ice nucleating particles (INPs) helps determining their role in the formation of precipitation. Here we describe and predict the concentrations of INPs active at −8 °C in precipitation samples collected at Jungfraujoch (CH, 3580 m a.s.l.). A high abundance of these INPs can be expected whenever a coincidence of high wind speed and first precipitation from an air mass occurs. This expands the set of conditions where such INPs could affect the onset of precipitation.
Lorenzo Menichetti, Thomas Kätterer, and Jens Leifeld
Biogeosciences, 13, 3003–3019,Short summary
Soil organic carbon dynamics are crucial for the global greenhouse gas balance, but their complexity is difficult to model and understand. We therefore often rely on radiocarbon measurements for calibrating models, but their effect on our understanding of the processes is still unclear. We calibrated five model structures on data from a long-term Swiss field experiment in a Bayesian framework to assess the effect of radiocarbon on the parameter and structural uncertainty of a soil carbon model.
Christine Alewell, Axel Birkholz, Katrin Meusburger, Yael Schindler Wildhaber, and Lionel Mabit
Biogeosciences, 13, 1587–1596,Short summary
Origin of suspended sediments in rivers is of crucial importance for optimization of catchment management. Sediment source attribution to a lowland river in central Switzerland with compound specific stable isotopes analysis (CSIA) indicated that 65 % of the suspended sediments originated from agricultural land during base flow, while forest was the dominant source during high flow. We achieved significant differences in CSIA signature from land uses dominated by C3 plant cultivation.
S. Osterwalder, J. Fritsche, C. Alewell, M. Schmutz, M. B. Nilsson, G. Jocher, J. Sommar, J. Rinne, and K. Bishop
Atmos. Meas. Tech., 9, 509–524,Short summary
Human activities have increased mercury (Hg) cycling between land and atmosphere. To define landscapes as sinks or sources of Hg we have developed an advanced REA system for long-term measurements of gaseous elemental Hg exchange. It was tested in two contrasting environments: above Basel, Switzerland, and a peatland in Sweden. Both landscapes showed net Hg emission (15 and 3 ng m−2 h−1, respectively). The novel system will help to advance our understanding of Hg exchange on an ecosystem scale.
R. Hüppi, R. Felber, A. Neftel, J. Six, and J. Leifeld
SOIL, 1, 707–717,Short summary
Biochar is considered an opportunity to tackle major environmental issues in agriculture. Adding pyrolised organic residues to soil may sequester carbon, increase yields and reduce nitrous oxide emissions from soil. It is unknown, whether the latter is induced by changes in soil pH. We show that biochar application substantially reduces nitrous oxide emissions from a temperate maize cropping system. However, the reduction was only achieved with biochar but not with liming.
J. Leifeld and J. Mayer
SOIL, 1, 537–542,Short summary
We present 14C data for field replicates of a controlled agricultural long-term experiment. We show that 14C variability is, on average, 12 times that of the analytical precision of the 14C measurement. Experimental 14C variability is related to neither management nor soil depth. Application of a simple carbon turnover model reveals that experimental variability of radiocarbon results in higher absolute uncertainties of estimated carbon turnover time for deeper soil layers.
J. P. Krüger, J. Leifeld, S. Glatzel, S. Szidat, and C. Alewell
Biogeosciences, 12, 2861–2871,Short summary
Biogeochemical soil parameters are studied to detect peatland degradation along a land use gradient (intensive, extensive, near-natural). Stable carbon isotopes, radiocarbon ages and ash content confirm peat growth in the near-natural bog but also indicate previous degradation. When the bog is managed extensively or intensively as grassland, all parameters indicate degradation and substantial C loss of the order of 18.8 to 42.9 kg C m-2.
K. Meusburger, G. Leitinger, L. Mabit, M. H. Mueller, A. Walter, and C. Alewell
Hydrol. Earth Syst. Sci., 18, 3763–3775,
J. Leifeld, C. Bader, E. Borraz, M. Hoffmann, M. Giebels, M. Sommer, and J. Augustin
Revised manuscript not accepted
S. Stanchi, M. Freppaz, E. Ceaglio, M. Maggioni, K. Meusburger, C. Alewell, and E. Zanini
Nat. Hazards Earth Syst. Sci., 14, 1761–1771,
E. Stopelli, F. Conen, L. Zimmermann, C. Alewell, and C. E. Morris
Atmos. Meas. Tech., 7, 129–134,
K. Meusburger, L. Mabit, J.-H. Park, T. Sandor, and C. Alewell
Biogeosciences, 10, 5627–5638,
K. Meusburger, G. Leitinger, L. Mabit, M. H. Mueller, and C. Alewell
Hydrol. Earth Syst. Sci. Discuss.,
M. H. Mueller, R. Weingartner, and C. Alewell
Hydrol. Earth Syst. Sci., 17, 1661–1679,
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Biogeosciences, 19, 3051–3071,Short summary
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Julia Gensel, Marc Steven Humphries, Matthias Zabel, David Sebag, Annette Hahn, and Enno Schefuß
Biogeosciences, 19, 2881–2902,Short summary
We investigated organic matter (OM) and plant-wax-derived biomarkers in sediments and plants along the Mkhuze River to constrain OM's origin and transport pathways within South Africa's largest freshwater wetland. Presently, it efficiently captures OM, so neither transport from upstream areas nor export from the swamp occurs. Thus, we emphasize that such geomorphological features can alter OM provenance, questioning the assumption of watershed-integrated information in downstream sediments.
Cordula Nina Gutekunst, Susanne Liebner, Anna-Kathrina Jenner, Klaus-Holger Knorr, Viktoria Unger, Franziska Koebsch, Erwin Don Racasa, Sizhong Yang, Michael Ernst Böttcher, Manon Janssen, Jens Kallmeyer, Denise Otto, Iris Schmiedinger, Lucas Winski, and Gerald Jurasinski
Methane emissions decreased after a seawater inflow and a preceding drought in freshwater rewetted coastal peatland. However, our microbial and greenhouse gas measurements do not indicate that methane consumers increased. Rather, methane producers co-existed in high numbers with their usual competitors, the sulfate-cycling bacteria. We studied the peat soil interdisciplinary and aimed to cover the soil-atmosphere continuum to better understand the sources of methane production and consumption.
Petri Kiuru, Marjo Palviainen, Tiia Grönholm, Maarit Raivonen, Lukas Kohl, Vincent Gauci, Iñaki Urzainki, and Annamari Laurén
Biogeosciences, 19, 1959–1977,Short summary
Peatlands are large sources of methane (CH4), and peat structure controls CH4 production and emissions. We used X-ray microtomography imaging, complex network theory methods, and pore network modeling to describe the properties of peat macropore networks and the role of macropores in CH4-related processes. We show that conditions for gas transport and CH4 production vary with depth and are affected by hysteresis, which may explain the hotspots and episodic spikes in peatland CH4 emissions.
Rey Harvey Suello, Simon Lucas Hernandez, Steven Bouillon, Jean-Philippe Belliard, Luis Dominguez-Granda, Marijn Van de Broek, Andrea Mishell Rosado Moncayo, John Ramos Veliz, Karem Pollette Ramirez, Gerard Govers, and Stijn Temmerman
Biogeosciences, 19, 1571–1585,Short summary
This research shows indications that the age of the mangrove forest and its position along a deltaic gradient (upstream–downstream) play a vital role in the amount and sources of carbon stored in the mangrove sediments. Our findings also imply that carbon capture by the mangrove ecosystem itself contributes partly but relatively little to long-term sediment organic carbon storage. This finding is particularly relevant for budgeting the potential of mangrove ecosystems to mitigate climate change.
Hao Tang, Susanne Liebner, Svenja Reents, Stefanie Nolte, Kai Jensen, Fabian Horn, and Peter Mueller
Biogeosciences, 18, 6133–6146,Short summary
We examined if sea-level rise and plant genotype interact to affect soil microbial functioning in a mesocosm experiment using two genotypes of a dominant salt-marsh grass characterized by differences in flooding sensitivity. Larger variability in microbial community structure, enzyme activity, and litter breakdown in soils with the more sensitive genotype supports our hypothesis that effects of climate change on soil microbial functioning can be controlled by plant intraspecific adaptations.
Naima Iram, Emad Kavehei, Damien T. Maher, Stuart E. Bunn, Mehran Rezaei Rashti, Bahareh Shahrabi Farahani, and Maria Fernanda Adame
Biogeosciences, 18, 5085–5096,Short summary
Greenhouse gas emissions were measured and compared from natural coastal wetlands and their converted agricultural lands across annual seasonal cycles in tropical Australia. Ponded pastures emitted ~ 200-fold-higher methane than any other tested land use type, suggesting the highest greenhouse gas mitigation potential and financial incentives by the restoration of ponded pastures to natural coastal wetlands.
Pavel Alekseychik, Aino Korrensalo, Ivan Mammarella, Samuli Launiainen, Eeva-Stiina Tuittila, Ilkka Korpela, and Timo Vesala
Biogeosciences, 18, 4681–4704,Short summary
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Timea Katona, Benjamin Silas Gilfedder, Sven Frei, Matthias Bücker, and Adrian Flores-Orozco
Biogeosciences, 18, 4039–4058,Short summary
We used electrical geophysical methods to map variations in the rates of microbial activity within a wetland. Our results show that the highest electrical conductive and capacitive properties relate to the highest concentrations of phosphates, carbon, and iron; thus, we can use them to characterize the geometry of the biogeochemically active areas or hotspots.
Jurek Müller and Fortunat Joos
Biogeosciences, 18, 3657–3687,Short summary
We present long-term projections of global peatland area and carbon with a continuous transient history since the Last Glacial Maximum. Our novel results show that large parts of today’s northern peatlands are at risk from past and future climate change, with larger emissions clearly connected to larger risks. The study includes comparisons between different emission and land-use scenarios, driver attribution through factorial simulations, and assessments of uncertainty from climate forcing.
Lianlian Zhu, Zhengmiao Deng, Yonghong Xie, Xu Li, Feng Li, Xinsheng Chen, Yeai Zou, Chengyi Zhang, and Wei Wang
Biogeosciences, 18, 1–11,Short summary
We conducted a Carex brevicuspis leaf litter input experiment to clarify the intrinsic factors controlling litter decomposition and quantify its contribution to the soil organic carbon pool at different water levels. Our results revealed that the water level in natural wetlands influenced litter decomposition mainly by leaching and microbial activity, by extension, and affected the wetland surface carbon pool.
Robert J. Parker, Chris Wilson, A. Anthony Bloom, Edward Comyn-Platt, Garry Hayman, Joe McNorton, Hartmut Boesch, and Martyn P. Chipperfield
Biogeosciences, 17, 5669–5691,Short summary
Wetlands contribute the largest uncertainty to the atmospheric methane budget. WetCHARTs is a simple, data-driven model that estimates wetland emissions using observations of precipitation and temperature. We perform the first detailed evaluation of WetCHARTs against satellite data and find it performs well in reproducing the observed wetland methane seasonal cycle for the majority of wetland regions. In regions where it performs poorly, we highlight incorrect wetland extent as a key reason.
Jurek Müller and Fortunat Joos
Biogeosciences, 17, 5285–5308,Short summary
We present an in-depth model analysis of transient peatland area and carbon dynamics over the last 22 000 years. Our novel results show that the consideration of both gross positive and negative area changes are necessary to understand the transient evolution of peatlands and their net effect on atmospheric carbon. The study includes the attributions to drivers through factorial simulations, assessments of uncertainty from climate forcing, and determination of the global net carbon balance.
Lilli Zeh, Marie Theresa Igel, Judith Schellekens, Juul Limpens, Luca Bragazza, and Karsten Kalbitz
Biogeosciences, 17, 4797–4813,
Jérémy Guilhen, Ahmad Al Bitar, Sabine Sauvage, Marie Parrens, Jean-Michel Martinez, Gwenael Abril, Patricia Moreira-Turcq, and José-Miguel Sánchez-Pérez
Biogeosciences, 17, 4297–4311,Short summary
The quantity of greenhouse gases (GHGs) released to the atmosphere by human industries and agriculture, such as carbon dioxide (CO2) and nitrous oxide (N2O), has been constantly increasing for the last few decades. This work develops a methodology which makes consistent both satellite observations and modelling of the Amazon basin to identify and quantify the role of wetlands in GHG emissions. We showed that these areas produce non-negligible emissions and are linked to land use.
Thomas Rosset, Stéphane Binet, Jean-Marc Antoine, Emilie Lerigoleur, François Rigal, and Laure Gandois
Biogeosciences, 17, 3705–3722,Short summary
Peatlands export a large amount of DOC through inland waters. This study aims at identifying the mechanisms controlling the DOC concentration at the outlet of two mountainous peatlands in the French Pyrenees. Peat water temperature and water table dynamics are shown to drive seasonal- and event-scale DOC concentration variation. According to water recession times, peatlands appear as complexes of different hydrological and biogeochemical units supplying inland waters at different rates.
David Holl, Eva-Maria Pfeiffer, and Lars Kutzbach
Biogeosciences, 17, 2853–2874,Short summary
We measured greenhouse gas (GHG) fluxes at a bog site in northwestern Germany that has been heavily degraded by peat mining. During the 2-year investigation period, half of the area was still being mined, whereas the remaining half had been rewetted shortly before. We could therefore estimate the impact of rewetting on GHG flux dynamics. Rewetting had a considerable effect on the annual GHG balance and led to increased (up to 84 %) methane and decreased (up to 40 %) carbon dioxide release.
Jacob S. Diamond, Daniel L. McLaughlin, Robert A. Slesak, and Atticus Stovall
Biogeosciences, 17, 901–915,Short summary
Many wetland systems exhibit lumpy, or uneven, soil surfaces where higher points are called hummocks and lower points are called hollows. We found that, while hummocks extended only ~ 20 cm above hollow surfaces, they exhibited distinct plant communities, plant growth, and soil properties. Differences between hummocks and hollows were the greatest in wetter sites, supporting the hypothesis that plants create and maintain their own hummocks in response to saturated soil conditions.
Terhi Riutta, Aino Korrensalo, Anna M. Laine, Jukka Laine, and Eeva-Stiina Tuittila
Biogeosciences, 17, 727–740,Short summary
We studied the role of plant species groups in peatland methane fluxes under natural conditions and lowered water level. At a natural water level, sedges and mosses increased the fluxes. At a lower water level, the impact of plant groups on the fluxes was small. Only at a high water level did vegetation regulate the fluxes. The results are relevant for assessing peatland methane fluxes in a changing climate, as peatland water level and vegetation are predicted to change.
M. Graham Clark, Elyn R. Humphreys, and Sean K. Carey
Biogeosciences, 17, 667–682,Short summary
Natural and restored wetlands typically emit methane to the atmosphere. However, we found that a wetland constructed after oil sand mining in boreal Canada using organic soils from local peatlands had negligible emissions of methane in its first 3 years. Methane production was likely suppressed due to an abundance of alternate inorganic electron acceptors. Methane emissions may increase in the future if the alternate electron acceptors continue to decrease.
Hendrik Reuter, Julia Gensel, Marcus Elvert, and Dominik Zak
Biogeosciences, 17, 499–514,Short summary
Using infrared spectroscopy, we developed a routine to disentangle microbial nitrogen (N) and plant N in decomposed litter. In a decomposition experiment in three wetland soils, this routine revealed preferential protein depolymerization as a decomposition-site-dependent parameter, unaffected by variations in initial litter N content. In Sphagnum peat, preferential protein depolymerization led to a N depletion of still-unprocessed litter tissue, i.e., a gradual loss of litter quality.
Kevan J. Minick, Bhaskar Mitra, Asko Noormets, and John S. King
Biogeosciences, 16, 4671–4686,Short summary
Sea level rise alters hydrology and vegetation in coastal wetlands. We studied effects of freshwater, saltwater, and wood on soil microbial activity in a freshwater forested wetland. Saltwater reduced CO2/CH4 production compared to freshwater, suggesting large changes in greenhouse gas production and microbial activity are possible due to saltwater intrusion into freshwater wetlands but that the availability of C in the form of dead wood (as forests transition to marsh) may alter the magnitude.
Jyrki Jauhiainen, Jukka Alm, Brynhildur Bjarnadottir, Ingeborg Callesen, Jesper R. Christiansen, Nicholas Clarke, Lise Dalsgaard, Hongxing He, Sabine Jordan, Vaiva Kazanavičiūtė, Leif Klemedtsson, Ari Lauren, Andis Lazdins, Aleksi Lehtonen, Annalea Lohila, Ainars Lupikis, Ülo Mander, Kari Minkkinen, Åsa Kasimir, Mats Olsson, Paavo Ojanen, Hlynur Óskarsson, Bjarni D. Sigurdsson, Gunnhild Søgaard, Kaido Soosaar, Lars Vesterdal, and Raija Laiho
Biogeosciences, 16, 4687–4703,Short summary
We collated peer-reviewed publications presenting GHG flux data for drained organic forest soils in boreal and temperate climate zones, focusing on data that have been used, or have the potential to be used, for estimating net annual soil GHG emission/removals. We evaluated the methods in data collection and identified major gaps in background/environmental data. Based on these, we developed suggestions for future GHG data collection to increase data applicability in syntheses and inventories.
Steffen Buessecker, Kaitlyn Tylor, Joshua Nye, Keith E. Holbert, Jose D. Urquiza Muñoz, Jennifer B. Glass, Hilairy E. Hartnett, and Hinsby Cadillo-Quiroz
Biogeosciences, 16, 4601–4612,Short summary
We investigated the potential for chemical reduction of nitrite into nitrous oxide (N2O) in soils from tropical peat. Among treatments, irradiation resulted in the lowest biological interference and least change of native soil chemistry (iron and organic matter). Nitrite depletion was as high in live or irradiated soils, and N2O production was significant in all tests. Thus, nonbiological production of N2O may be widely underestimated in wetlands and tropical peatlands.
Ward Swinnen, Nils Broothaerts, and Gert Verstraeten
Biogeosciences, 16, 3977–3996,Short summary
In this study, a new model is presented, which was specifically designed to study the development and carbon storage of blanket peatlands since the last ice age. In the past, two main processes (declining forest cover and rising temperatures) have been proposed as drivers of blanket peatland development on the British Isles. The simulations performed in this study support the temperature hypothesis for the blanket peatlands in the Cairngorms Mountains of central Scotland.
David Holl, Verónica Pancotto, Adrian Heger, Sergio Jose Camargo, and Lars Kutzbach
Biogeosciences, 16, 3397–3423,Short summary
We present 2 years of eddy covariance carbon dioxide flux data from two Southern Hemisphere peatlands on Tierra del Fuego. One of the investigated sites is a type of bog exclusive to the Southern Hemisphere, which is dominated by vascular, cushion-forming plants and is particularly understudied. One result of this study is that these cushion bogs apparently are highly productive in comparison to Northern and Southern Hemisphere moss-dominated bogs.
Liudmila S. Shirokova, Artem V. Chupakov, Svetlana A. Zabelina, Natalia V. Neverova, Dahedrey Payandi-Rolland, Carole Causserand, Jan Karlsson, and Oleg S. Pokrovsky
Biogeosciences, 16, 2511–2526,Short summary
Regardless of the size and landscape context of surface water in frozen peatland in NE Europe, the bio- and photo-degradability of dissolved organic matter (DOM) over a 1-month incubation across a range of temperatures was below 10 %. We challenge the paradigm of dominance of photolysis and biodegradation in DOM processing in surface waters from frozen peatland, and we hypothesize peat pore-water DOM degradation and respiration of sediments to be the main drivers of CO2 emission in this region.
Elisa Männistö, Aino Korrensalo, Pavel Alekseychik, Ivan Mammarella, Olli Peltola, Timo Vesala, and Eeva-Stiina Tuittila
Biogeosciences, 16, 2409–2421,Short summary
We studied methane emitted as episodic bubble release (ebullition) from water and bare peat surfaces of a boreal bog over three years. There was more ebullition from water than from bare peat surfaces, and it was controlled by peat temperature, water level, atmospheric pressure and the weekly temperature sum. However, the contribution of methane bubbles to the total ecosystem methane emission was small. This new information can be used to improve process models of peatland methane dynamics.
Franziska Koebsch, Matthias Winkel, Susanne Liebner, Bo Liu, Julia Westphal, Iris Schmiedinger, Alejandro Spitzy, Matthias Gehre, Gerald Jurasinski, Stefan Köhler, Viktoria Unger, Marian Koch, Torsten Sachs, and Michael E. Böttcher
Biogeosciences, 16, 1937–1953,Short summary
In natural coastal wetlands, high supplies of marine sulfate suppress methane production. We found these natural methane suppression mechanisms to be suspended by humane interference in a brackish wetland. Here, diking and freshwater rewetting had caused an efficient depletion of the sulfate reservoir and opened up favorable conditions for an intensive methane production. Our results demonstrate how human disturbance can turn coastal wetlands into distinct sources of the greenhouse gas methane.
Luke C. Jeffrey, Damien T. Maher, Scott G. Johnston, Kylie Maguire, Andrew D. L. Steven, and Douglas R. Tait
Biogeosciences, 16, 1799–1815,Short summary
Wetlands represent the largest natural source of methane (CH4), so understanding CH4 drivers is important for management and climate models. We compared several CH4 pathways of a remediated subtropical Australian wetland. We found permanently inundated sites emitted more CH4 than seasonally inundated sites and that the soil properties of each site corresponded to CH4 emissions. This suggests that selective wetland remediation of favourable soil types may help to mitigate unwanted CH4 emissions.
Ryo Shingubara, Atsuko Sugimoto, Jun Murase, Go Iwahana, Shunsuke Tei, Maochang Liang, Shinya Takano, Tomoki Morozumi, and Trofim C. Maximov
Biogeosciences, 16, 755–768,Short summary
(1) Wetting event with extreme precipitation increased methane emission from wetland, especially two summers later, despite the decline in water level after the wetting. (2) Isotopic compositions of methane in soil pore water suggested enhancement of production and less significance of oxidation in the following two summers after the wetting event. (3) Duration of water saturation in the active layer may be important for predicting methane emission after a wetting event in permafrost ecosystems.
Wiebke Münchberger, Klaus-Holger Knorr, Christian Blodau, Verónica A. Pancotto, and Till Kleinebecker
Biogeosciences, 16, 541–559,Short summary
Processes governing CH4 dynamics have been scarcely studied in southern hemispheric bogs. These can be dominated by cushion-forming plants with deep and dense roots suppressing emissions. Here we demonstrate how the spatial distribution of root activity drives a pronounced pattern of CH4 emissions, likewise also possible in densely rooted northern bogs. We conclude that presence of cushion vegetation as a proxy for negligible CH4 emissions from cushion bogs needs to be interpreted with caution.
Sarah Cook, Mick J. Whelan, Chris D. Evans, Vincent Gauci, Mike Peacock, Mark H. Garnett, Lip Khoon Kho, Yit Arn Teh, and Susan E. Page
Biogeosciences, 15, 7435–7450,Short summary
This paper presents the first comprehensive assessment of fluvial organic carbon loss from oil palm plantations on tropical peat: a carbon loss pathway previously unaccounted for from carbon budgets. Carbon in the water draining four plantations in Sarawak was monitored across a 1-year period. Greater fluvial carbon losses were linked to sites with lower water tables. These data will be used to complete the carbon budget from these ecosystems and assess the full impact of this land conversion.
Ariane Arias-Ortiz, Pere Masqué, Jordi Garcia-Orellana, Oscar Serrano, Inés Mazarrasa, Núria Marbà, Catherine E. Lovelock, Paul S. Lavery, and Carlos M. Duarte
Biogeosciences, 15, 6791–6818,Short summary
Efforts to include tidal marsh, mangrove and seagrass ecosystems in existing carbon mitigation strategies are limited by a lack of estimates of carbon accumulation rates (CARs). We discuss the use of 210Pb dating to determine CARs in these habitats, which are often composed of heterogeneous sediments and affected by sedimentary processes. Results show that obtaining reliable geochronologies in these systems is ambitious, but estimates of mean 100-year CARs are mostly secure within 20 % error.
Danielle D. Radu and Tim P. Duval
Biogeosciences, 15, 3937–3951,Short summary
Climate change can shift rainfall into fewer, more intense events with longer dry periods, leading to changes in peatland hydrology and carbon cycling. We manipulated rain events over three peatland plant types (moss, sedge, and shrub). We found increasing regime intensity led to drier surface soils and deeper water tables, reducing plant carbon uptake. Mosses became sources of CO2 after >3 consecutive dry days. This study shows peatlands may become smaller sinks for carbon due to rain changes.
Peter Mueller, Lisa M. Schile-Beers, Thomas J. Mozdzer, Gail L. Chmura, Thomas Dinter, Yakov Kuzyakov, Alma V. de Groot, Peter Esselink, Christian Smit, Andrea D'Alpaos, Carles Ibáñez, Magdalena Lazarus, Urs Neumeier, Beverly J. Johnson, Andrew H. Baldwin, Stephanie A. Yarwood, Diana I. Montemayor, Zaichao Yang, Jihua Wu, Kai Jensen, and Stefanie Nolte
Biogeosciences, 15, 3189–3202,
Karel Castro-Morales, Thomas Kleinen, Sonja Kaiser, Sönke Zaehle, Fanny Kittler, Min Jung Kwon, Christian Beer, and Mathias Göckede
Biogeosciences, 15, 2691–2722,Short summary
We present year-round methane emissions from wetlands in Northeast Siberia that were simulated with a land surface model. Ground-based flux measurements from the same area were used for evaluation of the model results, finding a best agreement with the observations in the summertime emissions that take place in this region predominantly through plants. During winter, methane emissions through the snow contribute 4 % of the total annual methane budget, but these are still underestimated.
Aino Korrensalo, Elisa Männistö, Pavel Alekseychik, Ivan Mammarella, Janne Rinne, Timo Vesala, and Eeva-Stiina Tuittila
Biogeosciences, 15, 1749–1761,Short summary
We measured methane fluxes of a boreal bog from six different plant community types in 2012–2014. We found only little variation in methane fluxes among plant community types. Peat temperature as well as both leaf area of plant species with air channels and of all vegetation are important factors controlling the fluxes. We also detected negative net fluxes indicating methane consumption each year. Our results can be used to improve the models of peatland methane dynamics under climate change.
Magnus Gålfalk, Martin Karlson, Patrick Crill, Philippe Bousquet, and David Bastviken
Biogeosciences, 15, 1549–1557,Short summary
We describe a quick in situ method for mapping ground surface cover, calculating areas of each surface type in a 10 x 10 m plot for each measurement. The method is robust, weather-independent, easily carried out, and uses wide-field imaging with a standard remote-controlled camera mounted on a very long extendible monopod from a height of 3–4.5 m. The method enables collection of detailed field reference data, critical in many remote sensing applications, such as wetland mapping.
Olli Peltola, Maarit Raivonen, Xuefei Li, and Timo Vesala
Biogeosciences, 15, 937–951,Short summary
Emission via bubbling, i.e. ebullition, is one of the main CH4 emission pathways from wetlands to the atmosphere, yet it is still coarsely represented in wetland CH4 models. In this study three ebullition modelling approaches are evaluated. Modeled annual CH4 emissions were similar, whereas temporal variability in CH4 emissions varied an order of magnitude between the approaches. Hence realistic description of ebullition is needed when models are compared to and calibrated against measurements.
Tracy Elsey-Quirk and Viktoria Unger
Biogeosciences, 15, 379–397,Short summary
Salt marshes have high rates of plant productivity and carbon accumulation. For this study, we found that differences in environmental conditions between estuary types were important in determining the source and stability of soil organic carbon. Specifically, sediment availability was extremely important in promoting high plant productivity and carbon accumulation in an estuary which was sediment-limited. In a sediment-rich estuary vegetation–soil-carbon relationships were weaker.
Jordan P. Goodrich, David I. Campbell, and Louis A. Schipper
Biogeosciences, 14, 4563–4576,
Jonathan P. Ritson, Richard E. Brazier, Nigel J. D. Graham, Chris Freeman, Michael R. Templeton, and Joanna M. Clark
Biogeosciences, 14, 2891–2902,Short summary
Peatlands are a globally important store of carbon; however increased droughts in the future may affect their ability to sequester carbon. Using laboratory simulations we show that droughts, through exposure to oxygen, greatly increase the quantity and alter the quality of dissolved organic carbon (DOC) released from peat. Catchment management which keeps water tables high to limit oxygen exposure is therefore likely to deliver positive water quality outcomes.
Sung-Ching Lee, Andreas Christen, Andrew T. Black, Mark S. Johnson, Rachhpal S. Jassal, Rick Ketler, Zoran Nesic, and Markus Merkens
Biogeosciences, 14, 2799–2814,Short summary
Burns Bog in Vancouver is the largest peatland on North America's west coast. It is undergoing rewetting as a restoration management after peat harvesting. Rewetting of disturbed areas facilitates their ecological recovery but has an immediate impact on carbon dioxide and methane exchange. On the floating flux tower, we quantified annual carbon dioxide and methane exchange to inform future management. Our results suggested that the study area was a net carbon sink after 7-year rewetting.
Amy E. Pickard, Kate V. Heal, Andrew R. McLeod, and Kerry J. Dinsmore
Biogeosciences, 14, 1793–1809,Short summary
Peatland catchments export significant volumes of photoreactive carbon to aquatic systems, particularly headwater streams. Delivery of photoreactive material is subject to seasonal variation, and is also influenced by the timing and magnitude of rainfall events. We suggest that photoprocessing of peatland derived carbon may contribute to carbon dioxide emissions from aquatic systems, although considerable uncertainty remains as to how much material is processed
in situwithin these systems.
Eva van den Elzen, Martine A. R. Kox, Sarah F. Harpenslager, Geert Hensgens, Christian Fritz, Mike S. M. Jetten, Katharina F. Ettwig, and Leon P. M. Lamers
Biogeosciences, 14, 1111–1122,Short summary
Peatlands are important because they sequester large amounts of carbon, for which nitrogen is needed. In peatlands dominated by peat mosses, atmospheric nitrogen is fixed by associated microorganisms. We here show for the first time experimentally that phosphorus availability and acid buffering, both showing large variations among peatlands, can explain the strong differences reported for nitrogen fixation. This improves our understanding of peatland functioning in relation to global change.
Paul J. Hanson, Jeffery S. Riggs, W. Robert Nettles, Jana R. Phillips, Misha B. Krassovski, Leslie A. Hook, Lianhong Gu, Andrew D. Richardson, Donald M. Aubrecht, Daniel M. Ricciuto, Jeffrey M. Warren, and Charlotte Barbier
Biogeosciences, 14, 861–883,Short summary
This paper describes operational methods to achieve whole-ecosystem warming (WEW) for tall-stature, high-carbon, boreal forest peatlands. The methods enable scientists to study immediate and longer-term (1 decade) responses of organisms (microbes to trees) and ecosystem functions (carbon, water and nutrient cycles). The WEW technology allows researchers to have a plausible glimpse of future environmental conditions for study that are not available in the current observational record.
Yingying Tang, Sarah F. Harpenslager, Monique M. L. van Kempen, Evi J. H. Verbaarschot, Laury M. J. M. Loeffen, Jan G. M. Roelofs, Alfons J. P. Smolders, and Leon P. M. Lamers
Biogeosciences, 14, 755–766,Short summary
Aquatic macrophytes can be used for wastewater polishing but not for purification. At a low nutrient loading M. spicatum and A. filiculoides performed equally well for P removal, whereas at loads ≥ 22 mg P m−2 d−1, A. filiculoides removes P more efficiently. We provide an easily applicable method to select efficient macrophytes species for wastewater polishing, which is essential for decision support in water management using constructed wetlands for nutrient removal by plant harvesting.
Marijn Van de Broek, Stijn Temmerman, Roel Merckx, and Gerard Govers
Biogeosciences, 13, 6611–6624,Short summary
The results of this study on the organic carbon (OC) stocks of tidal marshes show that variations in OC stocks along estuaries are important and should be taken into account to make accurate estimates of the total amount of OC stored in these ecosystems. Moreover, our results clearly show that most studies underestimate the variation in OC stocks along estuaries due to a shallow sampling depth, neglecting the variation in OC decomposition after burial along estuaries.
Rémon Saaltink, Stefan C. Dekker, Jasper Griffioen, and Martin J. Wassen
Biogeosciences, 13, 4945–4957,Short summary
We identified biogeochemical plant–soil feedback processes that occur when oxidation, drying and modification by plants alter sediment conditions. Wetland construction in Markermeer (a lake in the Netherlands) is used as a case study. Natural processes will be utilized during and after construction to accelerate ecosystem development. We conducted a 6-month greenhouse experiment to identify the key biogeochemical processes in the mud when Phragmites australis is used as an eco-engineer.
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