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On this page considered biochemistry journals:
Biogeochemistry - published by
Springer -
... publishes original papers and occasional reviews dealing with biotic controls on the chemistry of the environment, or with the geochemical control of the structure and function of ecosystems
Current research articles of the mentioned
journals:
Abstract Human alteration of the nitrogen cycle has stimulated research on nitrogen cycling in many aquatic and terrestrial ecosystems,
where analyses of nitrate (NO3−) by standard laboratory methods are common. A recent study by Colman et al. (Biogeochemistry 84:161–169, 2007) identified
a potential analytical interference of soluble iron (Fe) with NO3− quantification by standard flow-injection analysis of soil extracts, and suggested that this interference may have led Dail
et al. (Biogeochemistry 54:131–146, 2001) to make an erroneous assessment of abiotic nitrate immobilization in prior 15N pool dilution studies of Harvard Forest soils. In this paper, we reproduce the Fe interference problem systematically and
show that it is likely related to dissolved, complexed-Fe interfering with the colorimetric analysis of NO2−. We also show how standard additions of NO3− and NO2− to soil extracts at native dissolved Fe concentrations reveal when the Fe interference problem occurs, and permit the assessment
of its significance for past, present, and future analyses. We demonstrate low soluble Fe concentrations and good recovery
of standard additions of NO3− and NO2− in extracts of sterilized Harvard Forest soils. Hence, we maintain that rapid NO3− immobilization occurred in sterilized samples of the Harvard Forest O horizon in the study by Dail et al. (2001). Furthermore,
additional evidence is accumulating in the literature for rapid disappearance of NO3− added to soils, suggesting that our observations were not the result of an isolated analytical artifact. The conditions for
NO3− reduction are likely to be highly dependent on microsite properties, both in situ and in the laboratory. The so-called “ferrous
wheel hypothesis” (Davidson et al., Glob Chang Biol 9:228–236, 2003) remains an unproven, viable explanation for published
observations.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9231-6
Authors
Eric A. Davidson, The Woods Hole Research Center 149 Woods Hole Road Falmouth MA 02540-1644 USA
D. Bryan Dail, University of Maine Department of Plant, Soil, and Environmental Sciences Orono ME 04469 USA
Jon Chorover, University of Arizona Department of Soil, Water and Environmental Science Tucson AZ 85721-0038 USA
Abstract Rapid exchange of stream water and groundwater in streambeds creates hotspots of biogeochemical cycling of redox-sensitive
solutes. Although stream–groundwater interaction can be increased through stream restoration, there are few detailed studies
of the increased heterogeneity of water and solute fluxes through the streambed and associated patterns of biogeochemical
processes around stream restoration structures. In this study, we examined the seasonal patterns of water and solute fluxes
through the streambed around a stream restoration structure to relate patterns of water flux through the streambed to morphology
of the channel and biogeochemical processes occurring in the bed. We characterized different biogeochemical zones in the streambed
using principal component analysis (PCA) and examined the change in spatial patterns of these zones during different seasons.
The PCA results show that two principal components summarized 83% of the variance in the original data set. Streambed pore
water was characterized as oxic (indicating production of nitrate), anoxic (indicating sulfate, iron and manganese reduction),
or stream-like (indicating there was minimal change in the stream water chemistry in the bed). Regardless of season of the
year, anoxic zones were predominantly located upstream of the structure, in a low-velocity pool, and oxic zones were predominantly
located downstream of the structure, in a turbulent riffle. We expect structures that span the full channel, are impermeable,
and permanent, such as those installed in natural channel design restoration will similarly impact biogeochemical processing
in the streambed. The installation of these types of restoration structures may be a way to increase the degree of biogeochemical
cycling in stream ecosystems.
Content Type Journal Article
Category Synthesis and Emerging Ideas
DOI 10.1007/s10533-008-9235-2
Authors
L. K. Lautz, SUNY College of Environmental Science and Forestry Department of Forest and Natural Resources Management 1 Forestry Drive Syracuse NY 13224 USA
R. M. Fanelli, SUNY College of Environmental Science and Forestry Department of Forest and Natural Resources Management 1 Forestry Drive Syracuse NY 13224 USA
Abstract Phosphorus (P) dynamics in the agriculturally-dominated Minnesota River (USA) were examined in the lower 40 mile reach in
relation to hydrology, loading sources, suspended sediment, and chlorophyll to identify potential biotic and abiotic controls
over concentrations of soluble P and the recycling potential of particulate P during transport to the Upper Mississippi River.
Within this reach, wastewater treatment plant (WWTP) contributions as soluble reactive P (SRP) were greatest during very low
discharge and declined with increasing discharge and nonpoint source P loading. Concentrations of SRP declined during low
discharge in conjunction with increases in chlorophyll, suggesting biotic transformation to particulate P via phytoplankton
uptake. During higher discharge periods, SRP was constant at ~0.115 mg l−1 and coincided with an independently measured equilibrium P concentration (EPC) for suspended sediment in the river, suggesting
abiotic control over SRP via phosphate buffering. Particulate P (PP) accounted for 66% of the annual total P load. Redox-sensitive
PP, estimated using extraction procedures, represented 43% of the PP. Recycling potential of this load via diffusive sediment
P flux under anoxic conditions was conservatively estimated as ~17 mg m−2 d−1 using published regression equations. The reactive nature and high P recycling potential of suspended sediment loads in the
Minnesota River has important consequences for eutrophication of the Upper Mississippi River.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9232-5
Authors
William F. James, Eau Galle Aquatic Ecology Laboratory Engineer Research and Development Center W. 500 Eau Galle Dam Rd. Spring Valley WI 54767 USA
Catherine E. Larson, Metropolitan Council Environmental Services 390 Robert St. North St. Paul MN 55101-1805 USA
Abstract Variation in dissolved organic carbon (DOC) concentrations of surface waters is a consequence of process changes in the surrounding
terrestrial environment, both within annual cycles and over the longer term. Long-term records (1987–2006) of DOC concentrations
at six catchments (0.44–10.0 km2) across a climatic transect in Scotland were investigated for intra-annual relationships to evaluate potential long-term
seasonal patterns. The intra-annual mode of DOC export contrasted markedly between catchments and appeared dependent on their
hydrological characteristics. Catchments in wetter Central Scotland with high rainfall–runoff ratios, short transit times
and well-connected responsive soils show a distinct annual periodicity in DOC concentrations throughout the long-term datasets.
Increased DOC concentrations occurred between June and November with correspondingly lower DOC concentrations from December
to May. This appears unrelated to discharge, and is dependent mainly on higher temperatures driving biological activity, increasing
decomposition of available organic matter and solubility of DOC. The drier eastern catchments have lower rainfall–runoff ratios,
longer transit times and annual drying–wetting regimes linked to changing connectivity of soils. These are characterised by
seasonal DOC concentration–discharge relationships with an autumnal flush of DOC. Temperature influences the availability
of organic matter for DOC transport producing a high DOC concentration–discharge relationship in summer/autumn and low DOC
concentration–discharge relationship in winter/spring. These two distinct modes of seasonal DOC transport have important implications
for understanding changes in DOC concentrations and export brought about by climate change (temperature and precipitation)
and modelling of aquatic carbon losses from soil-types under different hydrological regimes.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9234-3
Authors
J. J. C. Dawson, University of Aberdeen School of Geosciences St Mary’s Building, Elphinstone Road Aberdeen AB24 3UF UK
C. Soulsby, University of Aberdeen School of Geosciences St Mary’s Building, Elphinstone Road Aberdeen AB24 3UF UK
D. Tetzlaff, University of Aberdeen School of Geosciences St Mary’s Building, Elphinstone Road Aberdeen AB24 3UF UK
M. Hrachowitz, University of Aberdeen School of Geosciences St Mary’s Building, Elphinstone Road Aberdeen AB24 3UF UK
S. M. Dunn, The Macaulay Institute Craigiebuckler Aberdeen AB15 8QH UK
I. A. Malcolm, Fisheries Research Services The Freshwater Laboratory Faskally Pitlochry Perthshire PH16 5LB UK
Abstract The effect of land use on the biogeochemistry of small tropical rivers and their estuaries was studied using the Kallada River
and Ashtamudi estuary located in the State of Kerala, India, as a model system. Water, suspended matter and sediments collected
during the monsoon and intermonsoon periods in 2002 and 2003 were analyzed for dissolved nutrients (nitrate, nitrite, phosphate,
silicate) and for phytoplankton abundance and composition, amino acid contents and stable carbon (C)) and nitrogen (N) isotope
ratios. Seasonal and spatial variations of dissolved nutrients and suspended matter along the course of the river point to
distinct differences in the C and N sources that are controlled by hydrology, geology and land use. Unusually low concentrations
of dissolved silicate and suspended matter suggest low erosion rates of the Precambrian basement rocks and the firm lateritic
soils in non-agricultural areas. Most dissolved nutrients and suspended particulate organic matter originated from fertilized
agricultural soils. The biogeochemistry of sedimentary organic matter indicates that most of the Kallada River load is deposited
in the upper Ashtamudi estuary, while the middle and lower parts have a stronger marine influence. The spatio-temporal variation
of dissolved and particulate river fluxes clearly indicates an effect of land use and land cover on the biogeochemistry of
the Kallada River. While the phosphate yield was high (6 × 103 mol km−2 year−1 or 185 kg km−2 year−1), the N yield was relatively low (10 × 103 mol km−2 year−1 or 141 kg km−2 year−1), which is unlike the situation in many other densely populated regions of tropical Asia.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9228-1
Authors
T. C. Jennerjahn, Leibniz Zentrum für Marine Tropenökologie Fahrenheitstrasse 6 28359 Bremen Germany
K. Soman, Centre for Earth Science Studies Akkulam, Thiruvananthapuram India
V. Ittekkot, Leibniz Zentrum für Marine Tropenökologie Fahrenheitstrasse 6 28359 Bremen Germany
I. Nordhaus, Leibniz Zentrum für Marine Tropenökologie Fahrenheitstrasse 6 28359 Bremen Germany
S. Sooraj, Centre for Earth Science Studies Akkulam, Thiruvananthapuram India
R. S. Priya, Centre for Earth Science Studies Akkulam, Thiruvananthapuram India
N. Lahajnar, Universität Hamburg Institut für Biogeochemie und Meereschemie Bundesstrasse 55 20146 Hamburg Germany
Abstract To help evaluate effects of Mississippi River inputs to sustainability of coastal Louisiana ecosystems, we compared porewater
and substrate quality of organic-rich Panicum hemitomon freshwater marshes inundated by river water annually for more than 30 years (Penchant basin, PB) or not during the same time
(Barataria basin, BB). In the marshes receiving river water the soil environment was more reduced, the organic substrate was
more decomposed and accumulated more sulfur. The porewater dissolved ammonium and orthophosphate concentrations were an order
of magnitude higher and sulfide and alkalinity concentrations were more than twice as high in PB compared with BB marshes.
The pH was higher and dissolved iron concentrations were more than an order of magnitude lower in PB marshes than in BB marshes.
The influx of nutrient-rich river water did not enhance end-of-year above-ground standing biomass or vertical accretion rates
of the shallow substrate. The differences in porewater chemistry and substrate quality are reasonably linked to the long-term
influx of river water through biogeochemical processes and transformations involving alkalinity, nitrate and sulfate. The
key factor is the continual replenishment of alkalinity, nitrate and sulfate via overland flow during high river stage each
year for several weeks to more than 6 months. This leads to a reducing soil environment, pooling of the phytotoxin sulfide
and inorganic nutrients in porewater, and internally generated alkalinity. Organic matter decomposition is enhanced under
these conditions and root mats degraded. The more decomposed root mat makes these marshes more susceptible to erosion during
infrequent high-energy events (for example hurricanes) and regular low-energy events, such as tides and the passage of weather
fronts. Our findings were unexpected and, if generally applicable, suggest that river diversions may not be the beneficial
mitigating agent of wetland restoration and conservation that they are anticipated to be.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9230-7
Authors
Christopher M. Swarzenski, USGS Louisiana Water Science Center 3535 S. Sherwood Forest Blvd. Baton Rouge LA 70816 USA
Thomas W. Doyle, USGS National Wetland Research Center 700 Cajun Dome Blvd. Lafayette LA 70508 USA
Brian Fry, Louisiana State University Coastal Ecology Institute Baton Rouge LA 70803 USA
Thomas G. Hargis, IAP World Services, National Wetland Research Center 700 Cajun Dome Blvd. Lafayette LA 70508 USA
Abstract Nitrogen from atmospheric deposition serves as the dominant source of new nitrogen to forested ecosystems in the northeastern
U.S. By combining isotopic data obtained using the denitrifier method, with chemical and hydrologic measurements we determined
the relative importance of sources and control mechanisms on nitrate (NO3−) export from five forested watersheds in the Connecticut River watershed. Microbially produced NO3− was the dominant source (82–100%) of NO3− to the sampled streams as indicated by the δ15N and δ18O of NO3−. Seasonal variations in the δ18O–NO3− in streamwater are controlled by shifting hydrologic and temperature affects on biotic processing, resulting in a relative
increase in unprocessed NO3− export during winter months. Mass balance estimates find that the unprocessed atmospherically derived NO3− stream flux represents less than 3% of the atmospherically delivered wet NO3− flux to the region. This suggests that despite chronically elevated nitrogen deposition these forests are not nitrogen saturated
and are retaining, removing, and reprocessing the vast majority of NO3− delivered to them throughout the year. These results confirm previous work within Northeastern U.S. forests and extend observations
to watersheds not dominated by a snow-melt driven hydrology. In contrast to previous work, unprocessed atmospherically derived
NO3− export is associated with the period of high recharge and low biotic activity as opposed to spring snowmelt and other large
runoff events.
Content Type Journal Article
DOI 10.1007/s10533-008-9227-2
Authors
Rebecca T. Barnes, Yale School of Forestry & Environmental Studies 21 Sachem Street New Haven CT 06511 USA
Peter A. Raymond, Yale School of Forestry & Environmental Studies 21 Sachem Street New Haven CT 06511 USA
Karen L. Casciotti, Woods Hole Oceanographic Institution Department of Marine Chemistry & Geochemistry 360 Woods Hole Road, Mail Stop 52 Woods Hole MA 02543 USA
Abstract The objective of this study was to evaluate the effect of N fertilization and the presence of N2 fixing leguminous trees on soil fluxes of greenhouse gases. For a one year period, we measured soil fluxes of nitrous oxide
(N2O), carbon dioxide (CO2) and methane (CH4), related soil parameters (temperature, water-filled pore space, mineral nitrogen content, N mineralization potential) and
litterfall in two highly fertilized (250 kg N ha−1 year−1) coffee cultivation: a monoculture (CM) and a culture shaded by the N2 fixing legume species Inga densiflora (CIn). Nitrogen fertilizer addition significantly influenced N2O emissions with 84% of the annual N2O emitted during the post fertilization periods, and temporarily increased soil respiration and decreased CH4 uptakes. The higher annual N2O emissions from the shaded plantation (5.8 ± 0.3 kg N ha−1 year−1) when compared to that from the monoculture (4.3 ± 0.1 kg N ha−1 year−1) was related to the higher N input through litterfall (246 ± 16 kg N ha−1 year−1) and higher potential soil N mineralization rate (3.7 ± 0.2 mg N kg−1 d.w. d−1) in the shaded cultivation when compared to the monoculture (153 ± 6.8 kg N ha−1 year−1 and 2.2 ± 0.2 mg N kg−1 d.w. d−1). This confirms that the presence of N2 fixing shade trees can increase N2O emissions. Annual CO2 and CH4 fluxes of both systems were similar (8.4 ± 2.6 and 7.5 ± 2.3 t C-CO2 ha−1 year−1, −1.1 ± 1.5 and 3.3 ± 1.1 kg C-CH4 ha−1 year−1, respectively in the CIn and CM plantations) but, unexpectedly increased during the dry season.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9222-7
Authors
Kristell Hergoualc’h, Centre de coopération International en Recherche Agronomique pour le Développement (CIRAD). UR Ecosystèmes de Plantations, s/c UR SeqBio-IRD (SupAgro) 2 place Viala, Bât. 12 34060 Montpellier Cedex 01 France
Ute Skiba, Center of Ecology and Hydrology (CEH) Bush Estate Penicuik EH26 0QB Scotland, UK
Jean-Michel Harmand, Centre de coopération International en Recherche Agronomique pour le Développement (CIRAD). UR Ecosystèmes de Plantations, s/c UR SeqBio-IRD (SupAgro) 2 place Viala, Bât. 12 34060 Montpellier Cedex 01 France
Catherine Hénault, Institut National de Recherche en Agronomie (INRA), UMR Microbiologie et Géochimie des Sols 17 rue de Sully BP 86510 21065 Dijon Cedex France
Abstract Today’s questions concerning the role of soil organic matter (SOM) in soil fertility, ecosystem functioning and global change
can only be addressed through knowledge of the controls on SOM stabilization and their interactions. Pyrolysis molecular beam
mass spectrometry (py-MBMS) provides a powerful and rapid means of assessing the biochemical composition of SOM. However,
characterization of SOM composition alone is insufficient to predict its dynamic behavior. Chemical fractionation is frequently
used to isolate more homogeneous SOM components, but the composition of fractions is frequently unknown. We characterized
biochemical SOM composition in two previously studied soils from the USA, under contrasting land uses: cultivated agriculture
and native vegetation. Bulk soils, as well as chemically isolated SOM fractions (humic acid, humin and non-acid hydrolysable),
were analyzed using py-MBMS. Principal components analysis (PCA) showed distinct differences in the SOM composition of isolated
fractions. Py-MBMS spectra and PCA loadings were dominated by low molecular weight fragments associated with peptides and
other N-containing compounds. The py-MBMS spectra were similar for native whole-soil samples under different vegetation, while
cultivation increased heterogeneity. An approach based on previously published data on marker signals also suggests the importance
of peptides in distinguishing samples. While the approach described here represents significant progress in the characterization
of changing SOM composition, a truly quantitative analysis will only be achieved using multiple internal standards and by
correcting for inorganic interference during py-MBMS analysis. Overall, we have provided proof of principle that py-MBMS can
be a powerful tool to understand the controls on SOM dynamics, and further method development is underway.
Content Type Journal Article
Category Synthesis and Emerging Ideas
DOI 10.1007/s10533-008-9218-3
Authors
Alain F. Plante, University of Pennsylvania Department of Earth & Environmental Science Hayden Hall, 240 South 33rd Street Philadelphia PA 19104-6316 USA
Kim Magrini-Bair, National Renewable Energy Laboratory Golden CO 80401 USA
Merle Vigil, USDA-ARS Akron CO 80720 USA
Eldor A. Paul, Colorado State University Natural Resource Ecology Laboratory Fort Collins CO 80521-1499 USA
Abstract Glacier surfaces are known to harbour abundant and active microbial communities. Phosphorus has been shown to be deficient
in glacial environments, and thus is one of the limits on microbial growth and activity. We quantified the phosphorus pool
in cryoconite debris and the concentration of dissolved phosphorus in supraglacial water on Werenskioldbreen, a Svalbard glacier.
The mean total P content of the cryoconite debris was ~2.2 mg g−1, which is significantly more than would be expected in rock debris from local sources. 57% of this P was present in the fraction
defined as organic P. It may account for the P in excess of the rock debris, and could be explained by allochthonous input
of organic matter. The concentration of total dissolved P in supraglacial water was very low (5.2–8.5 μg l−1), which was probably caused by efficient flushing and re-adsorption onto mineral surfaces. Dissolved organic P (DOP) was
a very important component of the dissolved phosphorus pool on Werenskioldbreen, as concentrations of DOP typically exceeded
those of dissolved inorganic P (or SRP) by more than four times in all the glacial water types. It is very difficult to assess
whether P was limiting in this environment solely on the basis of the N:P ratios in the debris or biomass. There may be some
degree of biological control over the C:N:P ratios in the debris, but the phosphorus cycling in the supraglacial environment
on this glacier seems to be mainly controlled by physical and geochemical processes.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9226-3
Authors
Marek Stibal, University of Bristol Bristol Glaciology Centre, School of Geographical Sciences University Road Bristol BS8 1SS UK
Martyn Tranter, University of Bristol Bristol Glaciology Centre, School of Geographical Sciences University Road Bristol BS8 1SS UK
Jon Telling, University of Bristol Bristol Glaciology Centre, School of Geographical Sciences University Road Bristol BS8 1SS UK
Liane G. Benning, University of Leeds Earth and Biosphere Institute, School of Earth and Environment Leeds LS2 9JT UK
Abstract Rates of ebullition and composition of bubbles were measured along a nutrient-enriched segment of the South Platte River below
Denver, Colorado. Ebullition was widespread in the South Platte up to 81 km downstream from Denver. Ebullitive fluxes of 0.44
and 0.29 g N m−2 d−1 were recorded at two sites downstream of Denver and represented 6–16% of the diffusive N2 efflux from this region. These data indicate that not accounting for ebullitive N2 losses can, at some locations, lead to a considerable underestimation of dentrification rates using the open-channel (gas
exchange) method. Gas bubbles often were >98% N2; methane dominated in a few organic-rich areas. Rates of ebullition related significantly to variations in temperature and
dissolved organic carbon. Ebullition was not observed in four tributaries of the South Platte River, despite their moderate
to high concentrations of nitrate and dissolved organic carbon. The data demonstrate that ebullition can contribute significantly
to N2 effluxes in running waters exhibiting high rates of denitrification.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9225-4
Authors
Tara M. Higgins, University of Colorado Center for Limnology, Cooperative Institute for Research in Environmental Sciences Boulder CO 80309-0216 USA
James H. McCutchan, University of Colorado Center for Limnology, Cooperative Institute for Research in Environmental Sciences Boulder CO 80309-0216 USA
William M. Lewis, University of Colorado Center for Limnology, Cooperative Institute for Research in Environmental Sciences Boulder CO 80309-0216 USA
Abstract Wetlands play an important role in determining the water quality of streams and are generally considered to act as a sink
for many reactive species. However, retention of chemical constituents varies seasonally and is affected by hydrologic and
biogeochemical processes including water source, mineral weathering, DOC and SPM cycling, redox status, precipitation/dissolution/adsorption,
and seasonal events. Relatively little is known about the influence of these factors on trace element cycling in wetland-influenced
streams. To explore the role of wetlands with respect to the retention/release of trace elements to streams, we examined temporal
and spatial patterns of concentrations of a large suite of trace elements (via ICP-MS) and geochemical drivers in five streams
and wetland rivulets draining natural wetlands in a northern Wisconsin watershed as well as in their groundwater sources (terrestrial
recharge, lake recharge, and older lake recharge). We performed principal components analyses of the concentrations of elements
and their geochemical drivers in both the streams and rivulets to assist in the identification of factors regulating trace
element concentrations. Variation in trace and major element concentrations among the streams was strongly related to the
proportion of terrestrial recharge contributing to the stream. A dominant influence of water source on rivulet chemistry was
supported by association of groundwater-sourced elements (Ba, Ca, Cs, Mg, Na, Si, Sr) with the primary statistical factor.
DOC appeared in the first principal component factor for the streams and in the second factor for the rivulets. Strong correlations
of Al, Cd, Ce, Cu, La, Pb, Ti, and Zn with DOC supported the important influence of DOC on trace metal cycling. A number of
elements in the rivulets (Al, La, Pb, Ti) and streams (Al, Ce, Cr, Cu, La, Pb, Ti, Zn) had a significant particulate cycle.
Redox cycling and precipitation/dissolution reactions involving Fe and Mn likely impacted Cu and Mo as evidenced by the low
levels in the rivulets. Variance in Fe, Mn and the metal oxy-anions was associated with factors related to redox cycling and
adsorption reactions in the wetland sediments. In streams, DOC and metals with a high affinity for DOC were associated with
a factor which also included negative loadings for groundwater-sourced elements, reflecting the importance of seasonal hydrologic
events which flush DOC and metals from wetland sediments and dilute groundwater sourced metals. Redox processes were of secondary
importance in the streams but of primary significance in the rivulets, documenting the importance of anoxic conditions in
wetland sediments on groundwater en route to the stream.
Content Type Journal Article
Category original article
DOI 10.1007/s10533-008-9219-2
Authors
Sara C. Kerr, University of Wisconsin-Madison Environmental Chemistry and Technology Program 660 N. Park St. Madison WI 53706 USA
Martin M. Shafer, University of Wisconsin-Madison Environmental Chemistry and Technology Program 660 N. Park St. Madison WI 53706 USA
Joel Overdier, University of Wisconsin-Madison Environmental Chemistry and Technology Program 660 N. Park St. Madison WI 53706 USA
David E. Armstrong, University of Wisconsin-Madison Environmental Chemistry and Technology Program 660 N. Park St. Madison WI 53706 USA
Abstract For soil carbon to be effectively sequestered beyond a timescale of a few decades, this carbon must become incorporated into
passive reservoirs or greater depths, yet the actual mechanisms by which this occurs is at best poorly known. In this study,
we quantified the magnitude of dissolved organic carbon (DOC) leaching and subsequent retention in soils of a coniferous forest
and a coastal prairie ecosystem. Despite small annual losses of DOC relative to respiratory losses, DOC leaching plays a significant
role in transporting C from surface horizons and stabilizing it within the mineral soil. We found that DOC movement into the
mineral soil constitutes 22% of the annual C inputs below 40 cm in a coniferous forest, whereas only 2% of the C inputs below
20 cm in a prairie soil could be accounted for by this process. In line with these C input estimates, we calculated advective
transport velocities of 1.05 and 0.45 mm year−1 for the forested and prairie sites, respectively. Radiocarbon measurements of field-collected DOC interpreted with a basic
transport-turnover model indicated that DOC which was transported and subsequently absorbed had a mean residence time of 90–150 years.
Given these residence times, the process of DOC movement and retention is responsible for 20% of the total mineral soil C
stock to 1 m in the forest soil and 9% in the prairie soil. These results provide quantitative data confirming differences
in C cycles in forests and grasslands, and suggest the need for incorporating a better mechanistic understanding of soil C
transport, storage and turnover processes into both local and regional C cycle models.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9221-8
Authors
Jonathan Sanderman, University of California Division of Ecosystem Sciences Berkeley CA USA
Ronald Amundson, University of California Division of Ecosystem Sciences Berkeley CA USA
Abstract Methane (CH4) is the second most important greenhouse gas after carbon dioxide (CO2). To understand CH4 cycling, quantitative information about microbial CH4 oxidation in soils is essential. Field methods such as the gas push-pull test (GPPT) to quantify CH4 oxidation are often used in combination with specific inhibitors, such as acetylene (C2H2). Acetylene irreversibly binds to the enzyme methane monooxygenase, but little is known about recovery of CH4 oxidation activity after C2H2 inhibition in situ, which is important when performing several experiments at the same location. To assess recovery of CH4 oxidation activity following C2H2 inhibition, we performed a series of GPPTs over 8 weeks at two different locations in the vadose zone above a petroleum hydrocarbon-contaminated
aquifer in Studen, Switzerland. After 4 weeks a maximum recovery of 30% and 50% of the respective initial activity was reached,
with a subsequent slight drop in activity at both locations. Likely, CH4 oxidation activity and CH4 concentrations were too low to allow for rapid recovery following C2H2 inhibition at the studied locations. Therefore, alternative competitive inhibitors have to be evaluated for application in
conjunction with GPPTs, especially for sites with low activity.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9223-6
Authors
Karina Urmann, ETH Zurich Institute of Biogeochemistry and Pollutant Dynamics Universitätsstrasse 16 8092 Zurich Switzerland
Martin H. Schroth, ETH Zurich Institute of Biogeochemistry and Pollutant Dynamics Universitätsstrasse 16 8092 Zurich Switzerland
Josef Zeyer, ETH Zurich Institute of Biogeochemistry and Pollutant Dynamics Universitätsstrasse 16 8092 Zurich Switzerland
Abstract This study examined changes in dissolved organic nitrogen (DON) and dissolved inorganic nitrogen (DIN) in coastal seawater
after exposure to sand along a high energy beach face over an annual cycle between April 2004 and July 2005. Dissolved organic
nitrogen, NO3−, and NH4+ were released from sand to seawater in laboratory incubation experiments clearly demonstrating that they are a potential
source of N to underlying groundwater or coastal seawater. DON increases in seawater, after exposure to surface sands in laboratory
experiments, were positively correlated with in situ water column DON concentrations measured at the same time as sand collection.
Increase in NO3− and NH4+ were not correlated with their in situ concentrations. This suggests that DON released from beach sands is relatively more
recalcitrant while NO3− and NH4+ are utilized rapidly in the coastal ocean. The release of N was seasonal with carbon to nitrogen ratios indicating that
recent primary productivity was responsible for the largest fluxes in summer while more degraded humic material contributed
to lower fluxes in winter. Fluxes of total dissolved nitrogen (DON and DIN) from surface sand (2.1 × 10−4 mol m−2 h−1) were similar to that of groundwater and more than an order of magnitude larger than rain deposition indicating the potential
importance of surface sand derived nitrogen to the coastal zone with a corresponding impact on primary productivity.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9224-5
Authors
G. Brooks Avery, University of North Carolina Wilmington Department of Chemistry and Biochemistry 601 South College Road Wilmington NC 28403-5932 USA
Robert J. Kieber, University of North Carolina Wilmington Department of Chemistry and Biochemistry 601 South College Road Wilmington NC 28403-5932 USA
Kelly J. Taylor, University of North Carolina Wilmington Department of Chemistry and Biochemistry 601 South College Road Wilmington NC 28403-5932 USA
Abstract The effect of phytodetritus derived from Phaeocystis sp. bloom on benthic mineralization processes has been determined at four intertidal stations along the French coast of the
eastern English Channel. Sites were chosen to offer a diversity of sediment types, from permeable sandy beach to estuarine
mudflats. Sediment Oxygen Demand (SOD) as well as total fluxes of Dissolved Inorganic Nitrogen (DIN) at the sediment–water
interface were determined by using whole core incubation technique and diffusive fluxes were predicted from interstitial water
concentrations. In the absence of phytodetritus deposits, a marked gradient of granulometric characteristics and organic matter
contents were observed, and resulted in more intensive mineralization processes in muddy sediments. Highly significant correlations
(P < 0.05) were evidenced between SOD and porosity, bacterial biomass, Organic Carbon and Organic Nitrogen, evidencing the direct
link between sediment texture, organic matter accumulation and microbial activity. The spring bloom led to a massive input
of organic matter in surficial sediments and mineralization rates significantly increased while higher DIN release towards
the water column was observed. A modification of the mineralization pathways was evidenced but clearly depended on the sediment
type. With a global view, benthic mineralization processes in the intertidal zone provided significant a part of DIN inputs
in the coastal zone while water column was depleted in nutrients.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9191-x
Authors
Mathieu Rauch, FRE ELICO CNRS n°2816, Université des Sciences et Technologie de Lille-Lille 1 Station Marine de Wimereux, Laboratoire Ecosystèmes Littoraux et Côtiers 28 Avenue Foch, BP 80 62930 Wimereux France
Lionel Denis, FRE ELICO CNRS n°2816, Université des Sciences et Technologie de Lille-Lille 1 Station Marine de Wimereux, Laboratoire Ecosystèmes Littoraux et Côtiers 28 Avenue Foch, BP 80 62930 Wimereux France
Abstract Black carbon (BC) is a quantitatively important C pool in the global C cycle due to its relative recalcitrance compared with
other C pools. However, mechanisms of BC oxidation and accompanying molecular changes are largely unknown. In this study,
the long-term dynamics in quality and quantity of BC were investigated in cultivated soil using X-ray photoelectron spectroscopy
(XPS), Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) techniques. BC particles and changes in BC stocks
were obtained from soil collected in fields that were cleared from forest by fire at 8 different times in the past (2, 3,
5, 20, 30, 50, 80 and 100 years before sampling) in western Kenya. BC contents rapidly decreased from 12.7 to 3.8 mg C g−1 soil during the first 30 years following deposition, after which they slowly decreased to a steady state at 3.5 mg C g−1 soil. BC-derived C losses from the top 0.1 m over 100 years were estimated at 6,000 kg C ha−1. The initial rapid changes in BC stocks resulted in a mean residence time of only around 8.3 years, which was likely a function
of both decomposition as well as transport processes. The molecular properties of BC changed more rapidly on surfaces than
in the interior of BC particles and more rapidly during the first 30 years than during the following 70 years. The Oc/C ratios
(Oc is O bound to C) and carbonyl groups (C=O) increased over the first 10 and 30 years by 133 and 192%, respectively, indicating
oxidation was an important process controlling BC quality. Al, Si, polysaccharides, and to a lesser extent Fe were found on
BC particle surfaces within the first few years after BC deposition to soil. The protection by physical and chemical stabilization
was apparently sufficient to not only minimize decomposition below detection between 30 and 100 years after deposition, but
also physical export by erosion and vertical transport below 0.1 m.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9220-9
Authors
Binh Thanh Nguyen, Cornell University Department of Crop and Soil Sciences 909 Bradfield Hall Ithaca NY 14853 USA
Johannes Lehmann, Cornell University Department of Crop and Soil Sciences 909 Bradfield Hall Ithaca NY 14853 USA
James Kinyangi, Cornell University Department of Crop and Soil Sciences 909 Bradfield Hall Ithaca NY 14853 USA
Ron Smernik, The University of Adelaide Soil and Land Systems, School of Earth and Environmental Sciences Adelaide Australia
Susan J. Riha, Cornell University Department of Earth and Atmospheric Sciences Ithaca NY 14853 USA
Mark H. Engelhard, PNNL Environmental Molecular Sciences Laboratory Richland WA 99352 USA
Abstract In this study, we examined changes in isotopic (13C and 14C) and spectroscopic (UV and 13C NMR) properties of dissolved organic carbon (DOC) in relation to soil organic matter (SOM) to elucidate the sources and
sinks of DOC as water percolates through the soils of two contrasting upland coastal California ecosystems—a redwood forest
and a coastal prairie. Despite differences in the distribution of C stocks and litter chemistry at these two sites, we found
similar shifts in DOC chemistry with soil depth. DOC concentrations dropped rapidly with increasing depth, with an accompanying
decrease in the C:N ratio, an increase in the δ13C value and an decrease in specific UV adsorption. In the grassland soil, Δ14C values declined from current atmospheric values (+70‰) in the surface horizon to −75‰ at 100 cm. In the redwood soil, the
Δ14C value of 111‰ in O horizon leachates was indicative of OM with a residence time of 8–10 yrs, with a decrease in Δ14C values to −80‰ at 100 cm. Solid-state CP/MAS 13C NMR spectra were generally most similar to highly humified OM, with a general decrease in the relative abundance of aromatic
compounds and an increase in the alkyl C/O-alkyl C ratio with increasing depth. All of these trends are consistent with the
shifts in SOM properties with increasing depth, which are interpreted to mean a shift from fresh plant material to older,
highly altered OM. In this Mediterranean climate, we found distinct seasonal shifts in the quantity and composition of DOC
found in soil solution during the winter rainy period that was also consistent with a shift from recent labile substrates
to older, highly altered OM. These results fit in with a growing body of literature suggesting that the source of much of
the DOC within mineral soils is the local soil OM, and the 14C data, in particular, indicate that DOC at depth is not simply the fraction of surficial leachates that have not been adsorbed
or decomposed. Rather, exchange reactions with a portion of the more stabilized SOM pool exert the strongest control on both
the concentration and composition of DOC found in these soils.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9211-x
Authors
Jonathan Sanderman, University of California Division of Ecosystem Sciences 137 Mulford Hall – MC3114 Berkeley CA 94720 USA
Jeffrey A. Baldock, CSIRO Land and Water Glen Osmond SA Australia
Ronald Amundson, University of California Division of Ecosystem Sciences 137 Mulford Hall – MC3114 Berkeley CA 94720 USA
Abstract This study addresses deep pore water chemistry in a permeable intertidal sand flat at the NW German coast. Sulphate, dissolved
organic carbon (DOC), nutrients, and several terminal metabolic products were studied down to 5 m sediment depth. By extending
the depth domain to several meters, insights into the functioning of deep sandy tidal flats were gained. Despite the dynamic
sedimentological conditions in the study area, the general depth profiles obtained in the relatively young intertidal flat
sediments of some metres depth are comparable to those determined in deep marine surface sediments. Besides diffusion and
lithology which control pore water profiles in most marine surface sediments, biogeochemical processes are influenced by advection
in the studied permeable intertidal flat sediments. This is supported by the model setup in which advection has to be implemented
to reproduce pore water profiles. Water exchange at the sediment surface and in deeper sediment layers converts these permeable
intertidal sediments into a “bio-reactor” where organic matter is recycled, and nutrients and DOC are released. At tidal flat
margins, a hydraulic gradient is generated, which leads to water flow towards the creekbank. Deep nutrient-rich pore waters
escaping at tidal flat margins during low tide presumably form a source of nutrients for the overlying water column in the
study area. Significant correlations between the inorganic products of terminal metabolism (NH4+ and PO43−) and sulphate depletion suggest sulphate reduction to be the dominant pathway of anaerobic carbon remineralisation. Pore
water concentrations of sulphate, ammonium, and phosphate were used to elucidate the composition of organic matter degraded
in the sediment. Calculated C:N and C:P ratios were supported by model results.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10533-008-9215-6
Authors
Melanie Beck, Carl von Ossietzky University Research Group Microbiogeochemistry, Institute for Chemistry and Biology of the Marine Environment (ICBM) PO Box 2503 26111 Oldenburg Germany
Olaf Dellwig, Carl von Ossietzky University Research Group Microbiogeochemistry, Institute for Chemistry and Biology of the Marine Environment (ICBM) PO Box 2503 26111 Oldenburg Germany
Jan M. Holstein, Carl von Ossietzky University Research Group Mathematical Modelling, Institute for Chemistry and Biology of the Marine Environment (ICBM) PO Box 2503 26111 Oldenburg Germany
Maik Grunwald, Carl von Ossietzky University Research Group Microbiogeochemistry, Institute for Chemistry and Biology of the Marine Environment (ICBM) PO Box 2503 26111 Oldenburg Germany
Bernhard Schnetger, Carl von Ossietzky University Research Group Microbiogeochemistry, Institute for Chemistry and Biology of the Marine Environment (ICBM) PO Box 2503 26111 Oldenburg Germany
Hans-Jürgen Brumsack, Carl von Ossietzky University Research Group Microbiogeochemistry, Institute for Chemistry and Biology of the Marine Environment (ICBM) PO Box 2503 26111 Oldenburg Germany
Abstract Unusually high SOC levels have been reported for sandy cropland soils in North-Western Europe. A potential link with their
general heathland land-use history was investigated by comparing two soil pairs of relict heathland and cultivated former
heathland in the Belgian sandy region. A sequential chemical fractionation yielded similar sizes in corresponding SOM fractions
between the heathland and cropland soils (i.e. NaOCl resistant: 12.3–15.0 g C kg−1 and NaOCl + HF resistant: 2.6–5.3 g C kg−1). Higher amounts of clay sized N in the cropland plots can be attributed to N additions from mineral fertilizers and animal
manure. Temperature resolved Pyrolysis Field Ionization Mass Spectroscopy analysis showed that the composition of both relict
heathland and cultivated soils was surprisingly similar, in spite of over 60 years of intense cropland management. The mass
spectra of SOM in both heathland-cropland soil pairs investigated was dominated by signals from lipids, alkylaromatics and
sterols. The accumulation of this SOM rich in aliphatics was logically linked to the high input of lipids, long-chain aliphatics
and sterols from heathland vegetation and the low soil pH and microbial activity. Based on the relatively high OC surface
loadings of HF-extractable OM (13–44 mg C m−2 Fe and 1.2–2.3 mg C m−2 clay), direct organo-mineral bonds between OM and Fe-oxides or clay minerals seem to be only partly involved as a stabilization
mechanism in these soils. The distinct bimodal shape of the thermograms indicates that OM-crosslinking could furthermore contribute
substantially to SOM stabilization in these soils. This study therefore corroborates the previously proposed view that lipids
may be bound in networks of alkylaromatics, the structural building blocks of OM macromolecules. We hypothesize that such
binding is able to explain the measured retention of these OM components, even under several decades of cropland management.
Content Type Journal Article
DOI 10.1007/s10533-008-9217-4
Authors
Steven Sleutel, Ghent University Department of Soil Management and Soil Care Coupure Links 653 9000 Gent Belgium
Peter Leinweber, University of Rostock Institute of Land Use Justus von Liebig Weg 6 18059 Rostock Germany
Shamim Ara Begum, Ghent University Department of Soil Management and Soil Care Coupure Links 653 9000 Gent Belgium
Mohammed Abdul Kader, Ghent University Department of Soil Management and Soil Care Coupure Links 653 9000 Gent Belgium
Patrick Van Oostveldt, Ghent University Department of Molecular Biotechnology Coupure Links 653 9000 Gent Belgium
Stefaan De Neve, Ghent University Department of Soil Management and Soil Care Coupure Links 653 9000 Gent Belgium
