• Issue

    Journal of Geophysical Research: Biogeosciences: Volume 122, Issue 1

    1-278
    January 2017
Previous Issue|Next Issue
Export Citation(s)

Issue Information

Free Access

Issue Information

  • Pages: 1
  • First Published: 09 February 2017

Research Articles

Free Access

Nitrate source apportionment using a combined dual isotope, chemical and bacterial property, and Bayesian model approach in river systems

Yongqiu Xia,  Yuefei Li,  Xinyu Zhang,  Xiaoyuan Yan, 
  • Pages: 2-14
  • First Published: 18 November 2016
Key Points

  • We outlined a combined procedure for improving the determination of NO3− sources in a paddy agriculture-urban gradient watershed
  • Denitrification was first incorporated into the Bayesian model
  • The variation and uncertainty of different NO3− sources were quantified via SIAR

Free Access

High terrestrial carbon load via groundwater to a boreal lake dominated by surface water inflow

Karolina Einarsdottir,  Marcus B. Wallin,  Sebastian Sobek, 
  • Pages: 15-29
  • First Published: 09 December 2016
Key Points

  • Significant terrestrial load of DOC, DIC, and CH4 via groundwater to a boreal lake, even though most water enters via streams
  • Terrestrial DIC load accounted for less than 12% of lake CO2 emission
  • Terrestrial DOC was more prone to mineralization and flocculation than lake DOC

Free Access

Spatiotemporal variability of lake pCO2 and CO2 fluxes in a hemiboreal catchment

Sivakiruthika Natchimuthu,  Ingrid Sundgren,  Magnus Gålfalk,  Leif Klemedtsson,  David Bastviken, 
  • Pages: 30-49
  • First Published: 14 December 2016
Key Points

  • Large spatial variability in lake pCO2aq observed especially during the thermally stratified period
  • Variability in pCO2aq influenced CO2 flux more than k both spatially and temporally
  • Measurements from ≥8 days scattered throughout the year at ≥5 points were required for representative fluxes

Free Access

Improving the accuracy of the gradient method for determining soil carbon dioxide efflux

Enrique P. Sánchez-Cañete,  Russell L. Scott,  Joost van Haren,  Greg A. Barron-Gafford, 
  • Pages: 50-64
  • First Published: 28 November 2016
Key Points

  • Published diffusion models produced soil efflux underestimations from 55% to 361%
  • Determining in situ diffusion estimates using conservative tracer injections did not produce favorable results
  • Calibrating a gas transfer model using automated chambers produced accurate long-term soil effluxes

Free Access

GIS-based prediction of stream chemistry using landscape composition, wet areas, and hydrological flow pathways

Tejshree Tiwari,  Fredrik Lidman,  Hjalmar Laudon,  William Lidberg,  Anneli M. Ågren, 
  • Pages: 65-79
  • First Published: 19 December 2016
Key Points

  • Patches in the landscape explain much of the spatial variability of stream chemistry
  • Landscape descriptors show a general distinction between more conservative and more nonconservative elements
  • Conservative elements are dependent on spatial scale of the landscape patch, while nonconservative elements are dependent on hydrologically active areas

Free Access

Quantitative, nondestructive estimates of coarse root biomass in a temperate pine forest using 3-D ground-penetrating radar (GPR)

Michelle Molon,  Joseph I. Boyce,  M. Altaf Arain, 
  • Pages: 80-102
  • First Published: 18 November 2016
Key Points

  • Roots as small as 1.4 cm diameter are detected with GPR
  • Large line spacing caused underestimation of root biomass
  • Detection of roots is highly dependent on soil moisture

Free Access

Seasonal divergence in the sensitivity of evapotranspiration to climate and vegetation growth in the Yellow River Basin, China

Tingting Pei,  Xiuchen Wu,  Xiaoyan Li,  Yu Zhang,  Fangzhong Shi,  Yujun Ma,  Pei Wang,  Cicheng Zhang, 
  • Pages: 103-118
  • First Published: 19 December 2016
Key Points

  • Precipitation and NDVI variations play a dominant role in controlling seasonal evapotranspiration changes in the Yellow River Basin
  • An approximate dipole pattern is discovered in the interannual ET sensitivity to NDVI variations in summer and autumn versus spring
  • Autumn vegetation growth plays a crucial role in controlling regional ET variations in the late growing season

Free Access

Coupled topographic and vegetation patterns in coastal dunes: Remote sensing observations and ecomorphodynamic implications

F. Yousefi Lalimi,  S. Silvestri,  L. J. Moore,  M. Marani, 
  • Pages: 119-130
  • First Published: 27 December 2016
Key Points

  • Lidar-derived LAI provides a quantitative characterization of vegetation biomass and topography in coastal dunes
  • Remote sensing can be used to quantify ecomorphodynamic patterns in dunes at the whole-system scale
  • Maximum vegetation productivity occurs on the landward side of the foredune crestline

Free Access

Biodegradation kinetics of dissolved organic matter chromatographic fractions in an intermittent river

N. Catalán,  J. P. Casas-Ruiz,  D. von Schiller,  L. Proia,  B. Obrador,  E. Zwirnmann,  R. Marcé, 
  • Pages: 131-144
  • First Published: 27 December 2016
Key Points

  • Low and high molecular weight DOM fractions' decay fitted the reactivity continuum while humic substances presented nonmonotonic patterns
  • Biodegradation patterns were consistent across sites, and the low molecular weight fraction drove the decay kinetics of bulk DOM
  • Variability in DOM composition across sites was induced by summer drought and determined the biodegradation kinetics

Free Access

Evaluation of a hierarchy of models reveals importance of substrate limitation for predicting carbon dioxide and methane exchange in restored wetlands

P. Y. Oikawa,  G. D. Jenerette,  S. H. Knox,  C. Sturtevant,  J. Verfaillie,  I. Dronova,  C. M. Poindexter,  E. Eichelmann,  D. D. Baldocchi, 
  • Pages: 145-167
  • First Published: 27 December 2016
Key Points

  • Using model-data fusion, we parameterized a hierarchy of biogeochemical models used to estimate CO2 and CH4 exchange in restored wetlands
  • In a validation exercise, the PEPRMT model was able to explain 70% and 50% of the variance in net exchange of CO2 and CH4, respectively
  • Simulation of soil carbon availability was critical for accurately predicting CO2 exchange in recently restored wetlands

Free Access

A simple hypothesis of how leaf and canopy-level transpiration and assimilation respond to elevated CO2 reveals distinct response patterns between disturbed and undisturbed vegetation

Randall J. Donohue,  Michael L. Roderick,  Tim R. McVicar,  Yuting Yang, 
  • Pages: 168-184
  • First Published: 27 December 2016
Key Points

  • A hypothesis to explain transpiration, assimilation, and LAI responses to elevated CO2
  • Hypothesized responses matched observed responses for undisturbed vegetation only
  • Transpiration responses of disturbed vegetation follow a fundamentally different pattern

Free Access
Highlight

Evaluation of oxygen isotope and Mg/Ca ratios in high-magnesium calcite from benthic foraminifera as a proxy for water temperature

Ayumi Maeda,  Kazuhiko Fujita,  Keiji Horikawa,  Atsushi Suzuki,  Toshihiro Yoshimura,  Yusuke Tamenori,  Hodaka Kawahata, 
  • Pages: 185-199
  • First Published: 27 December 2016
Key Points

  • Two species of benthic foraminifera were cultivated to establish a proxy for water temperature
  • Calcarina gaudichaudii showed high temperature correlation of δ18O and Mg/Ca ratio
  • Mg/Ca ratio in Amphisorus kudakajimensis shells was highly correlated with temperature

Free Access
Highlight

Low photolability of yedoma permafrost dissolved organic carbon

Aron Stubbins,  Paul J. Mann,  Leanne Powers,  Thais B. Bittar,  Thorsten Dittmar,  Cameron P. McIntyre,  Timothy I. Eglinton,  Nikita Zimov,  Robert G. M. Spencer, 
  • Pages: 200-211
  • First Published: 27 December 2016
Key Points

  • Ancient DOC is released from thawing permafrost soils into arctic rivers
  • Sunlight preferentially photomineralizes modern arctic river DOC leaving behind ancient permafrost DOC
  • Undetectable photochemical losses of permafrost DOC were accompanied by notable photomodification of DOM optical and molecular signatures

Free Access

Contributions of physical and biogeochemical processes to phytoplankton biomass enhancement in the surface and subsurface layers during the passage of Typhoon Damrey

Shanshan Pan,  Jie Shi,  Huiwang Gao,  Xinyu Guo,  Xiaohong Yao,  Xiang Gong, 
  • Pages: 212-229
  • First Published: 09 January 2017
Key Points

  • Typhoon Damrey increased the phytoplankton biomass in both the surface and subsurface layers
  • Phytoplankton biomass experienced different changing processes in the two layers
  • Contributions of physical and biogeochemical processes were different in the two layers

Free Access

Dynamics of soil organic carbon and nitrogen following agricultural abandonment in a karst region

Dejun Li,  Li Wen,  Liqiong Yang,  Pan Luo,  Kongcao Xiao,  Hao Chen,  Wei Zhang,  Xunyang He,  Hongsong Chen,  Kelin Wang, 
  • Pages: 230-242
  • First Published: 18 January 2017
Key Points

  • Soil C and N contents are greater over limestone than over dolomite
  • Soil C and N contents increase after agricultural abandonment over dolomite but not over limestone
  • Exchangeable Ca is key in controlling soil C and N dynamics following agricultural abandonment

Free Access

Winter respiratory C losses provide explanatory power for net ecosystem productivity

M. Haeni,  R. Zweifel,  W. Eugster,  A. Gessler,  S. Zielis,  C. Bernhofer,  A. Carrara,  T. Grünwald,  K. Havránková,  B. Heinesch,  M. Herbst,  A. Ibrom,  A. Knohl,  F. Lagergren,  B. E. Law,  M. Marek,  G. Matteucci,  J. H. McCaughey,  S. Minerbi,  L. Montagnani,  E. Moors,  J. Olejnik,  M. Pavelka,  K. Pilegaard,  G. Pita,  A. Rodrigues,  M. J. Sanz Sánchez,  M.-J. Schelhaas,  M. Urbaniak,  R. Valentini,  A. Varlagin,  T. Vesala,  C. Vincke,  J. Wu,  N. Buchmann, 
  • Pages: 243-260
  • First Published: 27 December 2016
Key Points

  • Compensation day (cDOY) is the day of year when net C losses during winter are compensated by net C uptake in spring
  • cDOY largely explains annual net ecosystem productivity NEPc of forests when the site has a distinct winter respiratory loss period
  • cDOY and its explanatory power depends on the integration method for annual NEPc and on the forest type

Free Access

Decreasing net primary production due to drought and slight decreases in solar radiation in China from 2000 to 2012

J. Wang,  J. Dong,  Y. Yi,  G. Lu,  J. Oyler,  W. K. Smith,  M. Zhao,  J. Liu,  S. Running, 
  • Pages: 261-278
  • First Published: 09 January 2017
Key Points

  • The global MODIS NPP product can be improved by using local daily meteorology data sets and biome-specific parameters
  • An overall decreasing NPP was largely dominated by forests over southern China which offset smaller increases in Northern China ecosystems
  • Reductions in NPP were largely due to decreases in solar radiation (82%), rather than the commonly expected effects of drought (18%)