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Title: Temporal dynamics of CO 2 and CH 4 loss potentials in response to rapid hydrological shifts in tidal freshwater wetland soils

Abstract

Earth System Models predict climate extremes that will impact regional and global hydrology. Aquatic-terrestrial transition zones like wetlands are subjected to the immediate consequence of climate change with shifts in the magnitude and dynamics of hydrologic flow. Such fluctuating hydrology can alter the nature and rate of biogeochemical transformations and significantly impact the carbon balance of the ecosystem. We tested the impacts of fluctuating hydrology and, specifically, the role of antecedent moisture conditions in determining the dominant carbon loss mechanisms in soils sampled from a tidal freshwater wetland system in the lower Columbia River, WA, USA. The objective was to understand shifts in biogeochemical processes in response to changing soil moisture, based on soil respiration and methane production rates, and to elucidate such responses based on the observed electron acceptor and metabolite profiles under laboratory conditions. Metabolomics and biogeochemical process rates provided evidence that soil redox was the principal factor driving metabolic function. Fluctuating redox conditions altered terminal electron acceptor and donor availability and recovery strengths of their concentrations in soil such that a disproportionate release of carbon dioxide stemmed from alternative anaerobic degradation processes like sulfate and iron reduction compared to carbon loss due to methanogenesis. These results showmore » that extended and short-term saturation created conditions conducive to increasing metabolite availability for anaerobic decomposition processes, with a significant lag in methanogenesis. In contrast, extended drying caused a cellular-level stress response and rapid recycling of alternate electron acceptors.« less

Authors:
 [1];  [2];  [1];  [1];  [1];  [1];  [3];  [1];  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Earth and Biological Sciences Directorate
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). National Security Directorate
  3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy and Environment Directorate
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1390570
Grant/Contract Number:
AC05-76RL01830; 1619948
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Ecological Engineering
Additional Journal Information:
Journal Volume: 114; Journal ID: ISSN 0925-8574
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Anaerobic respiration; Tidal wetlands; Methane production; Sulfate reduction; Iron reduction; Soil metabolites

Citation Formats

RoyChowdhury, Taniya, Bramer, Lisa, Hoyt, David W., Kim, Young-Mo, Metz, Thomas O., McCue, Lee Ann, Diefenderfer, Heida L., Jansson, Janet K., and Bailey, Vanessa. Temporal dynamics of CO 2 and CH 4 loss potentials in response to rapid hydrological shifts in tidal freshwater wetland soils. United States: N. p., 2017. Web. doi:10.1016/j.ecoleng.2017.06.041.
RoyChowdhury, Taniya, Bramer, Lisa, Hoyt, David W., Kim, Young-Mo, Metz, Thomas O., McCue, Lee Ann, Diefenderfer, Heida L., Jansson, Janet K., & Bailey, Vanessa. Temporal dynamics of CO 2 and CH 4 loss potentials in response to rapid hydrological shifts in tidal freshwater wetland soils. United States. doi:10.1016/j.ecoleng.2017.06.041.
RoyChowdhury, Taniya, Bramer, Lisa, Hoyt, David W., Kim, Young-Mo, Metz, Thomas O., McCue, Lee Ann, Diefenderfer, Heida L., Jansson, Janet K., and Bailey, Vanessa. Tue . "Temporal dynamics of CO 2 and CH 4 loss potentials in response to rapid hydrological shifts in tidal freshwater wetland soils". United States. doi:10.1016/j.ecoleng.2017.06.041.
@article{osti_1390570,
title = {Temporal dynamics of CO 2 and CH 4 loss potentials in response to rapid hydrological shifts in tidal freshwater wetland soils},
author = {RoyChowdhury, Taniya and Bramer, Lisa and Hoyt, David W. and Kim, Young-Mo and Metz, Thomas O. and McCue, Lee Ann and Diefenderfer, Heida L. and Jansson, Janet K. and Bailey, Vanessa},
abstractNote = {Earth System Models predict climate extremes that will impact regional and global hydrology. Aquatic-terrestrial transition zones like wetlands are subjected to the immediate consequence of climate change with shifts in the magnitude and dynamics of hydrologic flow. Such fluctuating hydrology can alter the nature and rate of biogeochemical transformations and significantly impact the carbon balance of the ecosystem. We tested the impacts of fluctuating hydrology and, specifically, the role of antecedent moisture conditions in determining the dominant carbon loss mechanisms in soils sampled from a tidal freshwater wetland system in the lower Columbia River, WA, USA. The objective was to understand shifts in biogeochemical processes in response to changing soil moisture, based on soil respiration and methane production rates, and to elucidate such responses based on the observed electron acceptor and metabolite profiles under laboratory conditions. Metabolomics and biogeochemical process rates provided evidence that soil redox was the principal factor driving metabolic function. Fluctuating redox conditions altered terminal electron acceptor and donor availability and recovery strengths of their concentrations in soil such that a disproportionate release of carbon dioxide stemmed from alternative anaerobic degradation processes like sulfate and iron reduction compared to carbon loss due to methanogenesis. These results show that extended and short-term saturation created conditions conducive to increasing metabolite availability for anaerobic decomposition processes, with a significant lag in methanogenesis. In contrast, extended drying caused a cellular-level stress response and rapid recycling of alternate electron acceptors.},
doi = {10.1016/j.ecoleng.2017.06.041},
journal = {Ecological Engineering},
number = ,
volume = 114,
place = {United States},
year = {Tue Jun 27 00:00:00 EDT 2017},
month = {Tue Jun 27 00:00:00 EDT 2017}
}

Journal Article:
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  • tEarth System Models predict climate extremes that will impact regional and global hydrology. Aquatic-terrestrial transition zones like wetlands are subjected to the immediate consequence of climate change with shifts in the magnitude and dynamics of hydrologic flow. Such fluctuating hydrology can alterthe nature and rate of biogeochemical transformations and significantly impact the carbon balance ofthe ecosystem. We tested the impacts of fluctuating hydrology and, specifically, the role of antecedentmoisture conditions in determining the dominant carbon loss mechanisms in soils sampled from a tidalfreshwater wetland system in the lower Columbia River, WA, USA. Our objective was to understand shiftsin biogeochemical processesmore » in response to changing soil moisture, based on soil respiration and methaneproduction rates, and to elucidate such responses based on the observed electron acceptor and metaboliteprofiles under laboratory conditions. Metabolomics and biogeochemical process rates provided evidencethat soil redox was the principal factor driving metabolic function. Fluctuating redox conditions alteredterminal electron acceptor and donor availability and recovery strengths of their concentrations in soilsuch that a disproportionate release of carbon dioxide stemmed from alternative anaerobic degradationprocesses like sulfate and iron reduction compared to carbon loss due to methanogenesis. Our resultsshow that extended and short-term saturation created conditions conducive to increasing metaboliteavailability for anaerobic decomposition processes, with a significant lag in methanogenesis. In contrast,extended drying caused a cellular-level stress response and rapid recycling of alternate electron acceptors.« less
  • We tested the hypothesis that carbon dioxide fertilization of plants will increase methane emissions from flooded soils because of increased rates of root exudation and root turnover. We grew an emergent aquatic macrophyte, Orontium aquatica, under ambient and twice-ambient levels of CO{sub 2} in continuously flooded pots for a period of six months. Soil methane flux increased from roughly 10 to 115 mg CH{sub 4} m{sup {minus}1} d{sup {minus}1} during the first three months with no significant difference between treatments. Thus, CO{sup 2}-fertilization did not stimulate CH{sub 4} emissions in the short-term. After six months, however, CH{sub 4} emissions weremore » significantly greater under elevated CO{sub 2} than ambient CO{sub 2} (423 {plus_minus}44 versus 131 {plus_minus} 28 mg CH{sub 4} m {sup {minus}1} d{sup {minus}1}, mean {plus_minus} se). While harvesting the plants, we found evidence that relatively high rates of transpiration under ambient CO{sub 2} had caused the soils to dry-out despite frequent watering. Our results suggest that in a future atmosphere with elevated CO{sup 2}, lower rates of transpiration may stimulate CH{sup 4} emissions by increasing the depth and duration of the anaerobic zone in soils.« less
  • The complexes (/sup +/-H)/sub 4/Ru/sub 4/(CO)/sub 10/(..mu..-)Ph/sub 2/P(CH/sub 2/)/sub n/PPh/sub 2/)) (n=1(1), 3 (3), 4 (4)), (..mu..-H)/sub 4/Ru/sub 4/(CO)/sub 10/(..mu..-)Ph/sub 2/PCH/sub 2/CH(CH/sub 3/)PPh/sub 2/)) (2a), (/sup +/-H)/sub 4/Ru/sub 4/(CO)/sub 10/)Ph/sub 2/PCH/sub 2/CH(CH/sub 3/)PPh/sub 2/) (2b), and ((..mu..-H)/sub 4/Ru/sub 4/(CO)/sub 11/)/sub 2/)Ph/sub 2/P(CH/sub 7/)/sub 5/PPh/sub 2/) (5a) have been characterized by IR, /sup 1/H NMR, and /sup 31/P NMR spectroscopy. The structures of compounds 1, 2a, 2b, 3, and 4 have been determined by single-crystal X-ray diffractometry. The diphosphine ligands are seen to bridge a Ru-Ru bond of the tetrahedral Ru/sub 4/ cluster in 1, 2a, 3, and 4, while themore » diphosphine ligand adopts a chelating mode of bonding in 2b. The hydride atoms in each of the structures were not located but were inferred from Ru-Ru bond lengths. They take up the same distribution of idealized C/sub s/ symmetry in all four structures. Where an asymmetric carbon atom is present (2a and 2b) only one of the two possible diastereoisomeric forms is found in the solid. Crystal data for the complexes are presented. 15 references, 4 figures, 8 tables.« less
  • The ..mu..-methylene cluster Ru/sub 3/(CO)/sub 7/(..mu..-CH)/..mu../sub 3/-eta/sup 3/-CH/sub 2/=C=C(i-Pr))/(..mu..-PPh/sub 2/) (2) synthesized from Ru/sub 3/-(CO)/sub 8//..mu..=eta/sup 3/-CH/sub 2/=C=C(i-Pr)/(..mu..-PPh/sub 2/) (1) via reaction with diazomethane, CH/sub 2/N/sub 2/, displays a remarkable reactivity associated with the ..mu..-CH/sub 2/ group under mild conditions. Slow isomerization of 2 to the 2-isopropyl-1,3-butadienediyl cluster (..mu..-H)Ru/sub 3/(CO)/sub 7//..mu../sub 3/-eta/sup 4/-CH=C(i-Pr)C=CH/sub 2//(..mu..-PPh/sub 2/) (3) (crystal data: triclinic, space group P anti 1, a = 9.333 (2) A, b = 10.200 (1) A, c = 16.297 (2) A, ..cap alpha.. = 87.25 (1)/sup 0/, ..beta.. = 83.26 (1)/sup 0/, ..gamma.. = 64.29 (1)/sup 0/, Z = 2, R =more » 0.25, R/sub w/ = 0.029 on 5899 observed reflections) occurs under nitrogen. Cluster 3 contains a triangular Ru/sub 3/ core with ..mu..-PPh/sub 2/ and ..mu..-H groups on one edge and a four-carbon hydrocarbyl ligand derived from a CH fragment of the ..mu..-methylene bride and the allenyl ligand of 2. Under an atmosphere of CO and in the presence of methanol complex 2 yields the open allenyl cluster Ru/sub 3/(CO)/sub 9//..mu../sub 3/-eta/sup 3/-CH/sub 2/=C=C(i-Pr)/(..mu..-PPh/sub 2/) (5) and methyl acetate, both of which were characterized spectroscopically.« less
  • New technetium(I) complexes of bidentate pseudoallyl ligands as triazenido, formamidinato, and acetamidinato have been synthesized and characterized. X-ray structure determinations of (Tc(PMe/sub 2/Ph)/sub 2/(CO)/sub 2/(p-CH/sub 3/C/sub 6/H/sub 4/N-N-NC/sub 6/H/sub 4/CH/sub 3/-p)) (1a) and (Tc(PMe/sub 2/Ph)/sub 2/(CO)/sub 2/(C/sub 6/H/sub 5/N-C(CH/sub 3/)-NC/sub 6/H/sub 5/)) (1c) show the technetium atom in a distorted octahedral coordination geometry with two axial PMe/sub 2/Ph and two cis-CO groups and the chelate ligands, which form a four-membered ring with the metal. Compound 1a crystallizes in space group Pbca of the orthorhombic system with a = 11.036 (2) A, b = 14.657 (4) A, c = 38.92 (1)more » A, and R = 0.045 for 3381 diffractometer data with I greater than or equal to 3sigma(I). Compound 1c crystallizes in the same space group, Pbca, with a = 8.954 (3) A, b = 16.727 (2) A, c = 41.435 (5) A, and R = 0.035 for 4108 diffractometer data with I greater than or equal to 3sigma(I). 31 references, 2 figures, 6 tables.« less