ALBERT

Description:    Cloud streets are common feature in the Amazon Basin. They form from the combination of the vertical trade wind stress and moist convection. Here, satellite imagery, data collected during the COBRA-PARÁ (Caxiuanã Observations in the Biosphere, River and Atmosphere of Pará) field campaign, and high resolution modeling are used to understand the streets′ formation and behavior. The observations show that the streets have an aspect ratio of about 3.5 and they reach their maximum activity around 15:00 UTC when the wind shear is weaker, and the convective boundary layer reaches its maximum height. The simulations reveal that the cloud streets onset is caused by the local circulations and convection produced at the interfaces between forest and rivers of the Amazon. The satellite data and modeling show that the large rivers anchor the cloud streets producing a quasi-stationary horizontal pattern. The streets are associated with horizontal roll vortices parallel to the mean flow that organizes the turbulence causing advection of latent heat flux towards the upward branches. The streets have multiple warm plumes that promote a connection between the rolls. These spatial patterns allow fundamental insights on the interpretation of the Amazon exchanges between surface and atmosphere with important consequences for the climate change understanding. Content Type Journal Article Pages 1-11 DOI 10.1007/s10533-011-9580-4 Authors Renato Ramos da Silva, Departamento de Física (CFM), Universidade Federal de Santa Catarina – UFSC, Campus Trindade, Florianopolis, SC 88040-900, Brazil Adilson W. Gandu, Depto de Ciências Atmosféricas, Universidade de São Paulo (USP), São Paulo, SP, Brazil Leonardo D. A. Sá, Centro Regional da Amazônia, Instituto Nacional de Pesquisas Espaciais (INPE), Belém, PA, Brazil Maria A. F. Silva Dias, Depto de Ciências Atmosféricas, Universidade de São Paulo (USP), São Paulo, SP, Brazil Journal Biogeochemistry Online ISSN 1573-515X Print ISSN 0168-2563

Description:    Conversion to no-till (NT) is usually associated to increased soil organic carbon (SOC) stocks in comparison to inversion tillage (IT). However, an important and unexplained variability in the changes in SOC with NT adoption exists, which impedes accurate prediction of its potential for C sequestration. We performed a meta-analysis with pedo-climatic and crop factors observed to influence SOC storage under NT at local and regional scales, in order to determine those better explaining this variability at a global scale. We studied SOC stocks (0–30 cm) in an equivalent soil mass, climatic and soil characteristics in 92 NT–IT paired cases. A sub-base with the 35 pairs providing C inputs was used to test their effect. Greater SOC stocks were observed with NT, with a smaller difference than often described (6.7%, i.e. 3.4 Mg C ha −1 ). Crop C inputs differences was the only factor significantly and positively related to SOC stock differences between NT and IT, explaining 30% of their variability. The variability in SOC storage induced by NT conversion seems largely related to the variability of the crop production response. Changes at the agro-ecosystem level, not only in soil, should be considered when assessing the potential of NT for C sequestration. Content Type Journal Article Pages 1-10 DOI 10.1007/s10533-011-9600-4 Authors Iñigo Virto, AgroParisTech, UMR BioEMCo, Bâtiment EGER, 78850 Thiverval-Grignon, France Pierre Barré, CNRS, UMR BioEMCo, Bâtiment EGER, 78850 Thiverval-Grignon, France Aurélien Burlot, Université Pierre et Marie Curie, UMR BioEMCo, 78850 Thiverval-Grignon, France Claire Chenu, AgroParisTech, UMR BioEMCo, Bâtiment EGER, 78850 Thiverval-Grignon, France Journal Biogeochemistry Online ISSN 1573-515X Print ISSN 0168-2563

Description:    Despite long-term enhanced nitrogen (N) inputs, forests can retain considerable amounts of N. While rates of N inputs via throughfall and N leaching are increased in coniferous stands relative to deciduous stands at comparable sites, N leaching below coniferous stands is disproportionally enhanced relative to the N input. A better understanding of factors affecting N retention is needed to assess the impact of changing N deposition on N cycling and N loss of forests. Therefore, gross N transformation pathways were quantified in undisturbed well-drained sandy soils of adjacent equal-aged deciduous (pedunculate oak ( Quercus robur L.)) and coniferous (Scots pine ( Pinus sylvestris L.)) planted forest stands located in a region with high N deposition (north Belgium). In situ inorganic 15 N labelling of the mineral topsoil (0–10 cm) combined with numerical data analysis demonstrated that (i) all gross N transformations differed significantly ( p  〈 0.05) between the two forest soils, (ii) gross N mineralization in the pine soil was less than half the rate in the oak soil, (iii) meaningful N immobilization was only observed for ammonium, (iv) nitrate production via oxidation of organic N occurred three times faster in the pine soil while ammonium oxidation was similar in both soils, and (v) dissimilatory nitrate reduction to ammonium was detected in both soils but was higher in the oak soil. We conclude that the higher gross nitrification (including oxidation of organic N) in the pine soil compared to the oak soil, combined with negligible nitrate immobilization, is in line with the observed higher nitrate leaching under the pine forest. Content Type Journal Article Pages 1-19 DOI 10.1007/s10533-011-9598-7 Authors Jeroen Staelens, Laboratory of Applied Physical Chemistry, ISOFYS, Ghent University, Coupure 653, 9000 Ghent, Belgium Tobias Rütting, Department of Plant and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden Dries Huygens, Laboratory of Applied Physical Chemistry, ISOFYS, Ghent University, Coupure 653, 9000 Ghent, Belgium An De Schrijver, Laboratory of Forestry, Ghent University, Geraardsbergsesteenweg 267, 9090 Gontrode, Belgium Christoph Müller, Department of Plant Ecology, Justus-Liebig-University Giessen, Giessen, Germany Kris Verheyen, Laboratory of Forestry, Ghent University, Geraardsbergsesteenweg 267, 9090 Gontrode, Belgium Pascal Boeckx, Laboratory of Applied Physical Chemistry, ISOFYS, Ghent University, Coupure 653, 9000 Ghent, Belgium Journal Biogeochemistry Online ISSN 1573-515X Print ISSN 0168-2563

Description:    Increasing leaching losses of carbon from soils due to accelerated weathering and increasing concentrations of dissolved carbon as a result of intensified soil respiration are suspected to provide a negative feedback on rising atmospheric CO 2 concentrations. We tested this hypothesis by studying concentrations of dissolved carbon and groundwater recharge at the Braunschweig free air carbon dioxide enrichment (FACE) experiment under winter wheat and winter barley. Dissolved carbon concentrations under elevated atmospheric CO 2 and ambient conditions were rather similar and not consistently higher under FACE. An analysis of δ 13 C signatures suggested that dissolved organic and inorganic carbon contained 9–29% (DOC) and 26–49% (DIC) of “new” carbon originating from CO 2 added to the FACE rings. Dissolved inorganic carbon additionally contained 15–42% of carbonate-derived C. A 15% reduction in evapotranspiration under elevated CO 2 increased groundwater recharge by 60 mm or 55%, which was the main driver for an observed 81% increase in dissolved carbon leaching from 2.7 to 4.9 g C m −2  year −1 at 90 cm depth. Our results suggest that future changes of dissolved carbon leaching losses will be mainly governed by changes in climate and groundwater recharge and to a lesser extent by increasing dissolved carbon concentrations. Content Type Journal Article Pages 1-14 DOI 10.1007/s10533-011-9584-0 Authors Jan Siemens, Department of Soil Science, Technische Universität Berlin, Salzufer 12, 10587 Berlin, Germany Andreas Pacholski, Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries, Bundesallee 50, 38116 Braunschweig, Germany Katia Heiduk, Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries, Bundesallee 50, 38116 Braunschweig, Germany Anette Giesemann, Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries, Bundesallee 50, 38116 Braunschweig, Germany Ulrike Schulte, Institute of Geology, Mineralogy and Geophysics, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany René Dechow, Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries, Bundesallee 50, 38116 Braunschweig, Germany Martin Kaupenjohann, Department of Soil Science, Technische Universität Berlin, Salzufer 12, 10587 Berlin, Germany Hans-Joachim Weigel, Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries, Bundesallee 50, 38116 Braunschweig, Germany Journal Biogeochemistry Online ISSN 1573-515X Print ISSN 0168-2563

Description:    Stream discharge–concentration relationships are indicators of terrestrial ecosystem function. Throughout the Amazon and Cerrado regions of Brazil rapid changes in land use and land cover may be altering these hydrochemical relationships. The current analysis focuses on factors controlling the discharge–calcium (Ca) concentration relationship since previous research in these regions has demonstrated both positive and negative slopes in linear log 10 discharge–log 10 Ca concentration regressions. The objective of the current study was to evaluate factors controlling stream discharge–Ca concentration relationships including year, season, stream order, vegetation cover, land use, and soil classification. It was hypothesized that land use and soil class are the most critical attributes controlling discharge–Ca concentration relationships. A multilevel, linear regression approach was utilized with data from 28 streams throughout Brazil. These streams come from three distinct regions and varied broadly in watershed size (〈1 to 〉10 6  ha) and discharge (10 −5.7 –10 3.2  m 3  s −1 ). Linear regressions of log 10 Ca versus log 10 discharge in 13 streams have a preponderance of negative slopes with only two streams having significant positive slopes. An ANOVA decomposition suggests the effect of discharge on Ca concentration is large but variable. Vegetation cover, which incorporates aspects of land use, explains the largest proportion of the variance in the effect of discharge on Ca followed by season and year. In contrast, stream order, land use, and soil class explain most of the variation in stream Ca concentration. In the current data set, soil class, which is related to lithology, has an important effect on Ca concentration but land use, likely through its effect on runoff concentration and hydrology, has a greater effect on discharge–concentration relationships. Content Type Journal Article Pages 1-17 DOI 10.1007/s10533-011-9574-2 Authors Daniel Markewitz, Warnell School of Forestry and Natural Resources, The University of Georgia, Athens, GA 30602, USA E. Conrad Lamon, Statistical Ecology Associates LLC, Canyon Lake, TX 78133, USA Mercedes C. Bustamante, Department of Ecology, University of Brasilia, Brasilia, DF 70910, Brazil Joaquin Chaves, Marine Biological Laboratory, Ecosystems Center, Woods Hole, MA 02543, USA Ricardo O. Figueiredo, EMBRAPA Amazônia Oriental, Belém, PA 66095, Brazil Mark S. Johnson, Department of Earth and Ocean Sciences, Institiute for Resources, Environment and Sustainability, University of British Columbia, Vancouver, BC V6T 1Z4, Canada Alex Krusche, Laboratório de Ecologia Isotópica, Centro de Energia Nuclear na Agricultura, University of São Paulo, Piracicaba, SP 13416, Brazil Christopher Neill, Marine Biological Laboratory, Ecosystems Center, Woods Hole, MA 02543, USA José S. O. Silva, Department of Ecology, University of Brasilia, Brasilia, DF 70910, Brazil Journal Biogeochemistry Online ISSN 1573-515X Print ISSN 0168-2563

Description:    Boreal peatlands have significant emissions of non-methane biogenic volatile organic compounds (BVOCs). Climate warming is expected to affect these ecosystems both directly, with increasing temperature, and indirectly, through water table drawdown following increased evapotranspiration. We assessed the combined effect of warming and water table drawdown on the BVOC emissions from boreal peatland microcosms. We also assessed the treatment effects on the BVOC emissions from the peat soil after the 7-week long experiment. Emissions of isoprene, monoterpenes, sesquiterpenes, other reactive VOCs and other VOCs were sampled using a conventional chamber technique, collected on adsorbent and analyzed by GC–MS. Carbon emitted as BVOCs was less than 1% of the CO 2 uptake and up to 3% of CH 4 emission. Water table drawdown surpassed the direct warming effect and significantly decreased the emissions of all BVOC groups. Only isoprene emission was significantly increased by warming, parallel to the increased leaf number of the dominant sedge Eriophorum vaginatum . BVOC emissions from peat soil were higher under the control and warming treatments than water table drawdown, suggesting an increased activity of anaerobic microbial community. Our results suggest that boreal peatlands could have concomitant negative and positive radiative forcing effects on climate warming following the effect of water table drawdown. The observed decrease in CH 4 emission causes a negative radiative forcing while the increase in CO 2 emission and decrease in reactive BVOC emissions, which could reduce the cooling effect induced by the lower formation rate of secondary organic aerosols, both contribute to increased radiative forcing. Content Type Journal Article Pages 1-14 DOI 10.1007/s10533-011-9578-y Authors Patrick Faubert, Department of Environmental Science, University of Eastern Finland, PO Box 1627, 70211 Kuopio, Finland Päivi Tiiva, Department of Environmental Science, University of Eastern Finland, PO Box 1627, 70211 Kuopio, Finland Tchamga Achille Nakam, Department of Environmental Science, University of Eastern Finland, PO Box 1627, 70211 Kuopio, Finland Jarmo K. Holopainen, Department of Environmental Science, University of Eastern Finland, PO Box 1627, 70211 Kuopio, Finland Toini Holopainen, Department of Environmental Science, University of Eastern Finland, PO Box 1627, 70211 Kuopio, Finland Riikka Rinnan, Department of Environmental Science, University of Eastern Finland, PO Box 1627, 70211 Kuopio, Finland Journal Biogeochemistry Online ISSN 1573-515X Print ISSN 0168-2563

Description:    The DyDOC model was used to simulate the soil carbon cycle of a deciduous forest at the Oak Ridge Reservation (Tennessee, USA). The model application relied on extensive data from the Enriched Background Isotope Study (EBIS), which exploited a short-term local atmospheric enrichment of radiocarbon to establish a large-scale manipulation experiment with different inputs of 14 C from both above-ground and below-ground litter. The model was first fitted to hydrological data, then observed pools and fluxes of carbon and 14 C data were used to fit parameters describing metabolic transformations of soil organic matter (SOM) components and the transport and sorption of dissolved organic matter (DOM). This produced a detailed quantitative description of soil C cycling in the three horizons (O, A, B) of the soil profile. According to the parameterised model, SOM turnover within the thin O-horizon rapidly produces DOM (46 gC m −2  a −1 ), which is predominantly hydrophobic. This DOM is nearly all adsorbed in the A- and B-horizons, and while most is mineralised relatively quickly, 11 gC m −2  a −1 undergoes a “maturing” reaction, producing mineral-associated stable SOM pools with mean residence times of 100–200 years. Only a small flux (~1 gC m −2  a −1 ) of hydrophilic DOM leaves the B-horizon. The SOM not associated with mineral matter is assumed to be derived from root litter, and turns over quite quickly (mean residence time 20–30 years). Although DyDOC was successfully fitted to C pools, annual fluxes and 14 C data, it accounted less well for short-term variations in DOC concentrations. Content Type Journal Article Pages 1-17 DOI 10.1007/s10533-011-9575-1 Authors E. Tipping, Centre for Ecology and Hydrology, Lancaster Environment Centre, Lancaster, LA1 4AP UK P. M. Chamberlain, Centre for Ecology and Hydrology, Lancaster Environment Centre, Lancaster, LA1 4AP UK M. Fröberg, Department of Soil and Environment, SLU – Sveriges Lantbruksuniversitet, 7001, 750 07 Uppsala, Sweden P. J. Hanson, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422, USA P. M. Jardine, Biosystems Engineering and Soil Science Department, Institute for a Secure and Sustainable Environment, University of Tennessee, Knoxville, TN 37996-4531, USA Journal Biogeochemistry Online ISSN 1573-515X Print ISSN 0168-2563

Description:    Understanding the quantity and quality of dissolved organic matter (DOM) in potential watershed sources is critical for explaining and quantifying the exports of DOM in stream runoff. Here, we examined the concentration and quality of DOM for ten watershed sources in a 12 ha forested catchment over a two-year period. DOM composition was evaluated for: throughfall, litter leachate, soil water (zero and tension), shallow and deep groundwater, stream water, hyporheic zone, and groundwater seeps. DOM quality was measured using a suite of optical indices including UV–visible absorbance and PARAFAC modeling of fluorescence excitation-emission matrices (EEMs). DOM concentrations and quality displayed a pronounced trend across watershed sources. Surficial watershed sources had higher DOM concentrations and more humic-like DOM with higher molecular weight whereas deeper groundwater sources were rich in % protein-like fluorescence. The greater % contribution of protein-like fluorescence in groundwater suggested that a larger fraction of groundwater DOM may be bioavailable. DOM for wetland groundwater was more aromatic and humic-like than that at the well-drained riparian location. Principal component analyses (PCA) revealed that the differences in surficial watershed compartments were dictated by humic-like components while groundwater sources separated out by % protein-like fluorescence. Observations from optical indices did not provide any conclusive evidence for preferential association of dissolved organic carbon (DOC) or dissolved organic nitrogen (DON) with any particular DOM quality pools. Content Type Journal Article Pages 1-22 DOI 10.1007/s10533-011-9572-4 Authors Shreeram Inamdar, Bioresources Engineering, University of Delaware, 264 Townsend Hall, 531 S College Avenue, Newark, DE 19716, USA Nina Finger, Bioresources Engineering, University of Delaware, 264 Townsend Hall, 531 S College Avenue, Newark, DE 19716, USA Shatrughan Singh, Bioresources Engineering, University of Delaware, 264 Townsend Hall, 531 S College Avenue, Newark, DE 19716, USA Myron Mitchell, SUNY-ESF, 1 Forestry Drive, Syracuse, NY 14210, USA Delphis Levia, Bioresources Engineering, University of Delaware, 264 Townsend Hall, 531 S College Avenue, Newark, DE 19716, USA Harsh Bais, Bioresources Engineering, University of Delaware, 264 Townsend Hall, 531 S College Avenue, Newark, DE 19716, USA Durelle Scott, Virginia Tech, Seitz Hall, Blacksburg, VA 24061, USA Patrick McHale, SUNY-ESF, 1 Forestry Drive, Syracuse, NY 14210, USA Journal Biogeochemistry Online ISSN 1573-515X Print ISSN 0168-2563

Description:    Climate change is predicted to lead to an increase in extreme rainfall and, in coastal areas, sea-salt deposition events. The impacts of these two climatic extremes on stream hydrochemistry were separately evaluated via a novel watering manipulation at the Gårdsjön experimental catchment, SW Sweden. In summer 2004, a 2000 m 2 hillslope draining to a defined stream reach was brought to a high-flow hydrological steady state for a 9 day period by sustained addition of ‘clean’ water using a distributed sprinkler system. Marine ions were then added, to generate a realistic ‘sea salt’ episode. A remarkably well constrained hydrological response was observed, such that a simple two-compartment mixing model could reasonably well reproduce observed conservative tracer (chloride, Cl) measurements, and 78% of added water was recovered in runoff. Stream base cation concentrations and acidity responded predictably to clean water and sea-salt addition, with the former leading to an increase in pH and acid neutralising capacity, and the latter to episodic acidification through hydrogen ion and aluminium displacement from soil exchange sites by marine base cations. Anion responses were less predictable: water addition caused a flush of nitrate, but this was apparently independent of rainfall composition. Sulphate remained near-constant during clean water addition but declined sharply during sea-salt addition, indicative of a strong, pH-dependent solubility control on leaching, presumably adsorption/desorption in the mineral soil. Most strikingly, dissolved organic carbon (DOC) concentrations were stable during clean water addition but varied dramatically in response to sea-salt addition, exhibiting a strong negative correlation with Cl concentrations in water draining the organic soil. These observations provide a robust experimental verification of the hypothesis that deposition chemistry, through its influence on acidity and/or ionic strength, has a major influence on DOC leaching to surface waters. Content Type Journal Article Pages 1-15 DOI 10.1007/s10533-010-9567-6 Authors Filip Moldan, IVL Swedish Environmental Research Institute, P.O. Box 5302, 400 14 Göteborg, Sweden Jakub Hruška, Czech Geological Survey, Klárov 3, 118 21 Praha 1, Czech Republic Christopher D. Evans, Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, LL57 2UW UK Michael Hauhs, University of Bayreuth, Dr.-Hans-Frisch-Straße 1-3, 954 48 Bayreuth, Germany Journal Biogeochemistry Online ISSN 1573-515X Print ISSN 0168-2563

Description:    Concentrations of cations (Na + , Ca 2+ , Mg 2+ , K + , NH 4 + ), anions (HCO 3 − , Cl − , NO 3 − , SO 4 2− , PO 4 3− ) and suspended sediments in the Madeira River water were determined near the city of Porto Velho (RO), in order to assess variation in water chemistry from 2004 to 2007. Calcium and bicarbonate were the dominant cation and anion, respectively. Significant seasonal differences were found, with highest concentrations occurring during the dry season, as expected from the drainage of Andean carbonate-rich substratum. Interannual variations were also observed, but became significant only when annual average discharge was 25% less than normal. Under this atypical discharge condition, bicarbonate was replaced by sulfate, and higher suspended sediment concentrations and loads were also observed. Compared to previously published studies, it appears that no significant changes in water chemistry have occurred during the last 20–30 years, although differences in approaches and sampling designs among this and previous studies may not allow detection of modest changes. The calculated suspended sediment load reported here is close to the values presented elsewhere, reinforcing the relative importance of this river as a sediment supplier for the Amazon Basin. Seasonality has a significant control on the chemistry of Madeira River waters, and severe decrease in discharge due to anthropogenic changes, such as construction of reservoirs or the occurrence of drier years—a plausible consequence of global climate change—may lead to modification in the chemical composition as well in the sediment deliver to the Amazon River. Content Type Journal Article Pages 1-15 DOI 10.1007/s10533-010-9568-5 Authors Nei K. Leite, CENA, University of São Paulo, Av Centenario, 303—Sao Dimas, Box 96, Piracicaba, SP 13416-903, Brazil Alex V. Krusche, CENA, University of São Paulo, Av Centenario, 303—Sao Dimas, Box 96, Piracicaba, SP 13416-903, Brazil Maria V. R. Ballester, CENA, University of São Paulo, Av Centenario, 303—Sao Dimas, Box 96, Piracicaba, SP 13416-903, Brazil Reynaldo L. Victoria, CENA, University of São Paulo, Av Centenario, 303—Sao Dimas, Box 96, Piracicaba, SP 13416-903, Brazil Jeffrey E. Richey, University of Washington, School of Oceanography, Box 355351, Seattle, WA 98195-5351, USA Beatriz M. Gomes, UNIR, Estrada do Itapirema, Ji-Paraná, RO 78960-000, Brazil Journal Biogeochemistry Online ISSN 1573-515X Print ISSN 0168-2563