23 results match your criteria Biogeosciences[Journal]

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Tale of Two Storms: Impact of Extreme Rain Events on the Biogeochemistry of Lake Superior.

J Geophys Res Biogeosci 2018 ;123(5):1719-1731

Large Lakes Observatory and Department of Chemistry and Biochemistry University of Minnesota, 2205 East 5 St. Duluth, MN 55812.

Climate change is expected to profoundly affect the Great Lakes region of North America. An increase in intensity and frequency of rain events is anticipated to deliver more runoff and to increase riverine inputs to Lake Superior's ecosystem. The effects of these changes on key biogeochemical parameters were analyzed by coupling satellite data, water column sensor profiles, and discrete surface-water sampling after two "500-year" flood events in the Lake Superior basin. Read More

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http://dx.doi.org/10.1029/2017JG004216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6381994PMC
January 2018
1 Read

Soil Carbon Dynamics in Soybean Cropland and Forests in Mato Grosso, Brazil.

J Geophys Res Biogeosci 2018 Jan 5;123(1):18-31. Epub 2018 Jan 5.

Max Planck Institute for Biogeochemistry Jena Germany.

Climate and land use models predict that tropical deforestation and conversion to cropland will produce a large flux of soil carbon (C) to the atmosphere from accelerated decomposition of soil organic matter (SOM). However, the C flux from the deep tropical soils on which most intensive crop agriculture is now expanding remains poorly constrained. To quantify the effect of intensive agriculture on tropical soil C, we compared C stocks, radiocarbon, and stable C isotopes to 2 m depth from forests and soybean cropland created from former pasture in Mato Grosso, Brazil. Read More

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http://dx.doi.org/10.1002/2017JG004269DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5993338PMC
January 2018
1 Read

Water, Energy, and Carbon with Artificial Neural Networks (WECANN): A statistically-based estimate of global surface turbulent fluxes and gross primary productivity using solar-induced fluorescence.

Biogeosciences 2017 20;14(18):4101-4124. Epub 2017 Sep 20.

Department of Earth and Environmental Engineering, Columbia University, New York, 10027, USA.

A new global estimate of surface turbulent fluxes, latent heat flux (LE) and sensible heat flux (H), and gross primary production (GPP) is developed using a machine learning approach informed by novel remotely sensed Solar-Induced Fluorescence (SIF) and other radiative and meteorological variables. This is the first study to jointly retrieve LE, H and GPP using SIF observations. The approach uses an artificial neural network (ANN) with a target dataset generated from three independent data sources, weighted based on triple collocation (TC) algorithm. Read More

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http://dx.doi.org/10.5194/bg-14-4101-2017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5744880PMC
September 2017
2 Reads

Quantifying biomass consumption and carbon release from the California Rim fire by integrating airborne LiDAR and Landsat OLI data.

J Geophys Res Biogeosci 2017 Feb 18;122(2):340-353. Epub 2017 Feb 18.

Centre for Landscape and Climate ResearchUniversity of LeicesterLeicesterUK; National Centre for Earth ObservationUniversity of LeicesterLeicesterUK.

Quantifying biomass consumption and carbon release is critical to understanding the role of fires in the carbon cycle and air quality. We present a methodology to estimate the biomass consumed and the carbon released by the California Rim fire by integrating postfire airborne LiDAR and multitemporal Landsat Operational Land Imager (OLI) imagery. First, a support vector regression (SVR) model was trained to estimate the aboveground biomass (AGB) from LiDAR-derived metrics over the unburned area. Read More

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http://dx.doi.org/10.1002/2015JG003315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5367322PMC
February 2017
10 Reads

Short-term favorable weather conditions are an important control of interannual variability in carbon and water fluxes.

J Geophys Res Biogeosci 2016 Aug 25;121(8):2186-2198. Epub 2016 Aug 25.

Institute for Atmospheric and Climate Science ETH Zurich Zurich Switzerland.

Ecosystem models often perform poorly in reproducing interannual variability in carbon and water fluxes, resulting in considerable uncertainty when estimating the land-carbon sink. While many aggregated variables (growing season length, seasonal precipitation, or temperature) have been suggested as predictors for interannual variability in carbon fluxes, their explanatory power is limited and uncertainties remain as to their relative contributions. Recent results show that the annual count of hours where evapotranspiration (ET) is larger than its 95th percentile is strongly correlated with the annual variability of ET and gross primary production (GPP) in an ecosystem model. Read More

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http://dx.doi.org/10.1002/2016JG003503DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5054815PMC
August 2016
17 Reads

Chesapeake Bay nitrogen fluxes derived from a land-estuarine ocean biogeochemical modeling system: Model description, evaluation, and nitrogen budgets.

J Geophys Res Biogeosci 2015 Aug 28;120(8):1666-1695. Epub 2015 Aug 28.

Horn Point Laboratory University of Maryland Center for Environmental Science Cambridge Maryland USA.

The Chesapeake Bay plays an important role in transforming riverine nutrients before they are exported to the adjacent continental shelf. Although the mean nitrogen budget of the Chesapeake Bay has been previously estimated from observations, uncertainties associated with interannually varying hydrological conditions remain. In this study, a land-estuarine-ocean biogeochemical modeling system is developed to quantify Chesapeake riverine nitrogen inputs, within-estuary nitrogen transformation processes and the ultimate export of nitrogen to the coastal ocean. Read More

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http://dx.doi.org/10.1002/2015JG002931DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5014239PMC
August 2015
11 Reads

Effects of different N sources on riverine DIN export and retention in a subtropical high-standing island, Taiwan.

Biogeosciences 2016;13(6):1787-1800. Epub 2016 Mar 23.

Department of Atmospheric Sciences, National Central University, Taoyuan, Taiwan.

Increases in nitrogen (N) availability and mobility resulting from anthropogenic activities have substantially altered the N cycle, both locally and globally. Taiwan characterized by the subtropical montane landscape with abundant rainfall, downwind of the most rapidly industrializing eastern coast of China, can be a demonstration site for extremely high N input and riverine DIN (dissolved inorganic N) export. We used 49 watersheds with similar climatic and landscape settings but classified into low, moderate, and highly disturbed categories based on population density to illustrate their differences in nitrogen inputs (through atmospheric N deposition, synthetic fertilizers, and human emission) and DIN export ratios. Read More

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http://dx.doi.org/10.5194/bg-13-1787-2016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4871224PMC
March 2016
3 Reads

Dissolved organic carbon fluxes in the Middle Atlantic Bight: An integrated approach based on satellite data and ocean model products.

J Geophys Res Biogeosci 2016 Feb 4;121(2):312-336. Epub 2016 Feb 4.

Department of Meteorology, Pennsylvania State University, University Park, Pennsylvania, USA.

Continental margins play an important role in global carbon cycle, accounting for 15-21% of the global marine primary production. Since carbon fluxes across continental margins from land to the open ocean are not well constrained, we undertook a study to develop satellite algorithms to retrieve dissolved organic carbon (DOC) and combined these satellite data with physical circulation model products to quantify the shelf boundary fluxes of DOC for the U.S. Read More

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http://dx.doi.org/10.1002/2015JG003031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5706124PMC
February 2016
10 Reads

Fossilized bioelectric wire - the trace fossil .

Biogeosciences 2015 Apr;12(8):2301-2309

Institut für Paläontologie, Universität Wien, Geozentrum, Althanstrasse 14, 1090 Vienna, Austria ; Faculty of Science, Department of Petroleum Geoscience, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410, Brunei.

The trace fossil is proposed as an indicator of fossil bioelectric bacterial activity at the oxic-anoxic interface zone of marine sediments. This fulfils the idea that such processes, commonly found in the modern realm, should be also present in the geological past. is an exceptional trace fossil due to its very thin diameter (mostly less than 1 mm) and common pyritic filling. Read More

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http://dx.doi.org/10.5194/bg-12-2301-2015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4538864PMC

Large increase in dissolved inorganic carbon flux from the Mississippi River to Gulf of Mexico due to climatic and anthropogenic changes over the 21st century.

J Geophys Res Biogeosci 2015 Apr 24;120(4):724-736. Epub 2015 Apr 24.

Department of Marine Sciences University of Georgia Athens Georgia USA.

It is recognized that anthropogenic factors have had a major impact on carbon fluxes from land to the ocean during the past two centuries. However, little is known about how future changes in climate, atmospheric CO, and land use may affect riverine carbon fluxes over the 21st century. Using a coupled hydrological-biogeochemical model, the Dynamic Land Ecosystem Model, this study examines potential changes in dissolved inorganic carbon (DIC) export from the Mississippi River basin to the Gulf of Mexico during 2010-2099 attributable to climate-related conditions (temperature and precipitation), atmospheric CO, and land use change. Read More

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http://dx.doi.org/10.1002/2014JG002761DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5032896PMC
April 2015
6 Reads

Methane and nitrous oxide exchange over a managed hay meadow.

Biogeosciences 2014 Dec;11(24):7219-7236

Institute of Ecology, University of Innsbruck, Austria ; European Academy of Bolzano, Bolzano, Italy.

The methane (CH) and nitrous oxide (NO) exchange of a temperate mountain grassland near Neustift, Austria, was measured during 2010-2012 over a time period of 22 months using the eddy covariance method. Exchange rates of both compounds at the site were low, with 97% of all half-hourly CH and NO fluxes ranging between ±200 and ±50 ng m s, respectively. The meadow acted as a sink for both compounds during certain time periods, but was a clear source of CH and NO on an annual timescale. Read More

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http://dx.doi.org/10.5194/bg-11-7219-2014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4373549PMC
December 2014
1 Read

Importance of nondiffusive transport for soil CO efflux in a temperate mountain grassland.

J Geophys Res Biogeosci 2015 Mar 24;120(3):502-512. Epub 2015 Mar 24.

Department of Biology University of Antwerp Wilrijk Belgium.

Soil respiration and its biotic and abiotic drivers have been an important research topic in recent years. While the bulk of these efforts has focused on the emission of CO from soils, the production and subsequent transport of CO from soil to atmosphere received far less attention. However, to understand processes underlying emissions of CO from terrestrial ecosystems, both processes need to be fully evaluated. Read More

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http://dx.doi.org/10.1002/2014JG002788DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4950304PMC
March 2015
5 Reads

Models of fluorescence and photosynthesis for interpreting measurements of solar-induced chlorophyll fluorescence.

J Geophys Res Biogeosci 2014 Dec 26;119(12):2312-2327. Epub 2014 Dec 26.

Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH Jülich, Germany.

We have extended a conventional photosynthesis model to simulate field and laboratory measurements of chlorophyll fluorescence at the leaf scale. The fluorescence paramaterization is based on a close nonlinear relationship between the relative light saturation of photosynthesis and nonradiative energy dissipation in plants of different species. This relationship diverged only among examined data sets under stressed (strongly light saturated) conditions, possibly caused by differences in xanthophyll pigment concentrations. Read More

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http://dx.doi.org/10.1002/2014JG002713DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4852699PMC
December 2014

Management and climate contributions to satellite-derived active fire trends in the contiguous United States.

J Geophys Res Biogeosci 2014 Apr 28;119(4):645-660. Epub 2014 Apr 28.

Department of Earth System Science, University of California Irvine, California, USA.

Fires in croplands, plantations, and rangelands contribute significantly to fire emissions in the United States, yet are often overshadowed by wildland fires in efforts to develop inventories or estimate responses to climate change. Here we quantified decadal trends, interannual variability, and seasonality of Terra Moderate Resolution Imaging Spectroradiometer (MODIS) observations of active fires (thermal anomalies) as a function of management type in the contiguous U.S. Read More

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http://dx.doi.org/10.1002/2013JG002382DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4508926PMC
April 2014
4 Reads

A model-based insight into the coupling of nitrogen and sulfur cycles in a coastal upwelling system.

J Geophys Res Biogeosci 2014 Mar 19;119(3):264-285. Epub 2014 Mar 19.

Nordic Center for Earth Evolution (NordCEE) and Department of Geosciences and Natural Resource Management, University of Copenhagen København K, Denmark.

The biogeochemical cycling in oxygen-minimum zones (OMZs) is dominated by the interactions of microbial nitrogen transformations and, as recently observed in the Chilean upwelling system, also through the energetically less favorable remineralization of sulfate reduction. The latter process is masked, however, by rapid sulfide oxidation, most likely through nitrate reduction. Thus, the cryptic sulfur cycle links with the nitrogen cycle in OMZ settings. Read More

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http://dx.doi.org/10.1002/2012JG002271DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4508913PMC

Oxygen isotopes in tree rings record variation in precipitation O and amount effects in the south of Mexico.

J Geophys Res Biogeosci 2013 Dec 6;118(4):1604-1615. Epub 2013 Dec 6.

Earth and Global Change, School of Geography, University of Leeds Leeds, UK.

[1] Natural archives of oxygen isotopes in precipitation may be used to study changes in the hydrological cycle in the tropics, but their interpretation is not straightforward. We studied to which degree tree rings of from southern Mexico record variation in isotopic composition of precipitation and which climatic processes influence oxygen isotopes in tree rings (O). Interannual variation in O was highly synchronized between trees and closely related to isotopic composition of rain measured at San Salvador, 710 km to the southwest. Read More

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http://dx.doi.org/10.1002/2013JG002304DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4508921PMC
December 2013
3 Reads

Development of a regional-scale pollen emission and transport modeling framework for investigating the impact of climate change on allergic airway disease.

Biogeosciences 2013 Mar;10(3):3977-4023

Laboratory for Atmospheric Research, Department of Civil and Environmental Engineering, Washington State University, Pullman, WA, USA.

Exposure to bioaerosol allergens such as pollen can cause exacerbations of allergenic airway disease (AAD) in sensitive populations, and thus cause serious public health problems. Assessing these health impacts by linking the airborne pollen levels, concentrations of respirable allergenic material, and human allergenic response under current and future climate conditions is a key step toward developing preventive and adaptive actions. To that end, a regional-scale pollen emission and transport modeling framework was developed that treats allergenic pollens as non-reactive tracers within the WRF/CMAQ air-quality modeling system. Read More

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http://www.biogeosciences.net/11/1461/2014/bg-11-1461-2014.p
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https://www.cmascenter.org/conference/2012/abstracts/zhang_d
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http://www.biogeosciences-discuss.net/10/3977/2013/
Publisher Site
http://dx.doi.org/10.5194/bgd-10-3977-2013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4021721PMC
March 2013
7 Reads

Biotic, abiotic and management controls on methanol exchange above a temperate mountain grassland.

J Geophys Res Biogeosci 2011 Sep;116(G3)

Institute of Ecology, University of Innsbruck, Austria.

Methanol (CHOH) fluxes were quantified above a managed temperate mountain grassland in the Stubai Valley (Tyrol, Austria) during the growing seasons 2008 and 2009. Half-hourly methanol fluxes were calculated by means of the virtual disjunct eddy covariance (vDEC) method using 3-dimensional wind data from a sonic anemometer and methanol volume mixing ratios measured with a proton-transfer-reaction mass spectrometer (PTR-MS). During (undisturbed) mature and growing phases methanol fluxes exhibited a clear diurnal cycle with close-to-zero fluxes during nighttime and emissions, up to 10 nmol m s, which followed the diurnal course of radiation and air temperature. Read More

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http://dx.doi.org/10.1029/2011jg001641DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3859319PMC
September 2011
13 Reads

Land use affects the net ecosystem CO(2) exchange and its components in mountain grasslands.

Biogeosciences 2010 Aug;7(8):2297-2309

Institute of Ecology, University of Innsbruck, Sternwartestr. 15, 6020 Innsbruck, Austria.

Changes in land use and management have been strongly affecting mountain grassland, however, their effects on the net ecosystem exchange of CO(2) (NEE) and its components have not yet been well documented. We analysed chamber-based estimates of NEE, gross primary productivity (GPP), ecosystem respiration (R) and light use efficiency (LUE) of six mountain grasslands differing in land use and management, and thus site fertility, for the growing seasons of 2002 to 2008. The main findings of the study are that: (1) land use and management affected seasonal NEE, GPP and R, which all decreased from managed to unmanaged grasslands; (2) these changes were explained by differences in leaf area index (LAI), biomass and leaf-area-independent changes that were likely related to photosynthetic physiology; (3) diurnal variations of NEE were primarily controlled by photosynthetically active photon flux density and soil and air temperature; seasonal variations were associated with changes in LAI; (4) parameters of light response curves were generally closely related to each other, and the ratio of R at a reference temperature/ maximum GPP was nearly constant across the sites; (5) similarly to our study, maximum GPP and R for other grasslands on the globe decreased with decreasing land use intensity, while their ratio remained remarkably constant. Read More

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http://dx.doi.org/10.5194/bg-7-2297-2010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3535888PMC

Soil respiration at mean annual temperature predicts annual total across vegetation types and biomes.

Biogeosciences 2010 Jul;7(7):2147-2157

Institute of Ecology, University of Innsbruck, Innsbruck, Austria.

Soil respiration (SR) constitutes the largest flux of CO(2) from terrestrial ecosystems to the atmosphere. However, there still exist considerable uncertainties as to its actual magnitude, as well as its spatial and interannual variability. Based on a reanalysis and synthesis of 80 site-years for 57 forests, plantations, savannas, shrublands and grasslands from boreal to tropical climates we present evidence that total annual SR is closely related to SR at mean annual soil temperature (SR(MAT)), irrespective of the type of ecosystem and biome. Read More

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http://dx.doi.org/10.5194/bg-7-2147-2010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3535887PMC

BVOC fluxes above mountain grassland.

Biogeosciences 2010 May;7(5)

Institute of Ion Physics and Applied Physics, University of Innsbruck, Austria.

Grasslands comprise natural tropical savannah over managed temperate fields to tundra and cover one quarter of the Earth's land surface. Plant growth, maintenance and decay result in volatile organic compound (VOCs) emissions to the atmosphere. Furthermore, biogenic VOCs (BVOCs) are emitted as a consequence of various environmental stresses including cutting and drying during harvesting. Read More

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http://www.biogeosciences.net/7/1413/2010/
Publisher Site
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3856874PMC
http://dx.doi.org/10.5194/bg-7-1413-2010DOI Listing
May 2010
2 Reads

Estimating carbon dioxide fluxes from temperate mountain grasslands using broad-band vegetation indices.

Biogeosciences 2010 Feb;7(2):683-694

Institute of Ecology, University of Innsbruck, Innsbruck, Austria.

The broad-band normalised difference vegetation index (NDVI) and the simple ratio (SR) were calculated from measurements of reflectance of photosynthetically active and short-wave radiation at two temperate mountain grasslands in Austria and related to the net ecosystem CO exchange (NEE) measured concurrently by means of the eddy covariance method. There was no significant statistical difference between the relationships of midday mean NEE with narrow- and broad-band NDVI and SR, measured during and calculated for that same time window, respectively. The skill of broad-band NDVI and SR in predicting CO fluxes was higher for metrics dominated by gross photosynthesis and lowest for ecosystem respiration, with NEE in between. Read More

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3856878PMC
February 2010

Leaf area controls on energy partitioning of a temperate mountain grassland.

Biogeosciences 2008 Mar;5(2)

Institut für Ökologie, Universität Innsbruck, Sternwartestr. 15, 6020 Innsbruck, Austria.

Using a six year data set of eddy covariance flux measurements of sensible and latent heat, soil heat flux, net radiation, above-ground phytomass and meteorological driving forces energy partitioning was investigated at a temperate mountain grassland managed as a hay meadow in the Stubai Valley (Austria). The main findings of the study were: (i) Energy partitioning was dominated by latent heat, followed by sensible heat and the soil heat flux; (ii) When compared to standard environmental forcings, the amount of green plant matter, which due to three cuts varied considerably during the vegetation period, explained similar, and partially larger, fractions of the variability in energy partitioning; (iii) There were little, if any, indications of water stress effects on energy partitioning, despite reductions in soil water availability in combination with high evaporative demand, e.g. Read More

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http://dx.doi.org/10.5194/bg-5-421-2008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3858997PMC
March 2008
26 Reads
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