DOI: 10.5061/dryad.xd2547dq8
title: Long-distance electron transfer along redox gradients in the subsurface

description: Electron transfer (ET) is the fundamental process of life and element
 cycling. In the subsurface, the distance of ET determines its influencing
 area, normally as short as nanometers or micrometers. Here we provide
 direct evidence from column experiments that ET can last over 10 cm along
 the redox gradient in sediment columns, through a long-distance ET chain
 constituted by a series of short-distance electron hopping reactions
 involving with microbes and redox-active species like iron ions (and/or
 minerals) and natural organic matters. Microbial processes contribute
 largely under biologically active conditions, while chemical processes are
 important under extremely acidic/alkaline and cold conditions. Microbial
 and chemical processes synergistically mediate the long-distance ET
 process, with an estimated electron flux of 6.73 μmol e-/cm2 per day. This
 long-distance ET represents an overlooked but important background process
 influencing subsurface biogeochemical processes and remediation
 activities.
description: The data in this dataset were obtained through
 experimental testing, and the calculations and processing are documented
 within the dataset. For detailed information about the dataset, please
 refer to the "README" file.
description: # Long-distance electron transfer along redox gradients in the subsurface
 This dataset corresponds
 to the experimental source data associated with the research paper titled
 "Long-distance electron transfer along redox gradients in the
 subsurface." The data, obtained through experimental testing, include
 comprehensive insights into empirical foundations and results presented in
 the paper. The dataset is structured within a compressed archive
 containing 2 folders and 6 Excel tables. ## Description of the data and
 file structure FOLDER & FILE OVERVIEW 1\. Folder List: A)
 Sediment_EDCandFeII Including the following six lists: a)    
 Initial_EDCandFeII.xlsx b)     DifferentTextures_EDC.xlsx c)    
 DifferentTextures_Fe(II).xlsx d)     DifferentSterilized_EDC.xlsx e)    
 DifferentSterilized_FeII.xlsx f)      DifferentPerturbated_EDC.xlsx B)
 SedimentPoreWater_DissolvedSpecies Including the following three lists:
 a)     Sterilized_Pertuated_DissolvedSpecies.xlsx b)    
 SedimentPoreWater_EDCandEAC.xlsx c)     Gamma_DissolvedSpecies.xlsx   2\.
 Individual File List: A) XRD.xlsx B) EDC_Feasibility.xlsx C) RNA_based_16S
 rRNA_genes.xlsx D) AmpliconSequenceAnalysis_MicrobialCommunity.xlsx E)
 PerturbatedColumns_pH.xlsx F) ETflux_CalculationData.xlsx 3\. Relationship
 between files, if important: None 4\. Additional related data collected
 that was not included in the current data package: None 5\. Are there
 multiple versions of the dataset? No
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: Initial_EDCandFeII.xlsx 1\. Number of data
 titles: 20 2\. Number of sheets: 2 3\. Experimental systems： \* sand
 column (treated by HgCl2 + NaN3): the sand loams in the column were
 immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling. \* silt
 column (treated by HgCl2 + NaN3): the silt loams in the column were
 immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling. \* clay
 loam-1 column (treated by HgCl2 + NaN3): the clay loam-1 sediments in the
 column were immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling.
 \* clay loam-1 column (inclusion of sand): the clay loam-1 column (treated
 by HgCl2 + NaN3) was filled with inclusion of sand at the interface. \*
 clay loam-1 column (inclusion of 1-cm sterilized): the clay loam-1 column
 (treated by HgCl2 + NaN3) was with inclusion of a 1-cm thick clay loam-1
 interlayer treated by concentrated HgCl2 + NaN3 above or below the
 interface \* untreated clay loam-1 columns: the clay loam-1 column with no
 treatment. \* autoclaved clay loam-1 columns: the clay loam-1 sediments in
 the column were autoclaved prior to filling. \* O2-perturbated clay loam-1
 columns: the clay loam-1 column was treated by O2-perturbation. \* high
 initial △Eh of clay loam-2 + clay loam-1 columns (treated by HgCl2 +
 NaN3): this column refers to the bottom half filled with reduced clay
 loam-1 and the upper half filled with oxidized clay loam-2. Both clay
 loam-1 and clay loam-2 sediments in the column were immersed in 250 mg/L
 HgCl2 and 500 mg/L NaN3 prior to filling. \* untreated clay loam-2
 columns: the clay loam-2 column with no treatment. *“Low temperature” clay
 loam-2 columns: the clay loam-2 column was treated by low temperature.
 *“Acid perturbation” clay loam-2 columns: the initial pH of clay loam-2
 sediments in the column was acidified to ~4. *“Base perturbation” clay
 loam-2 columns: the initial pH of clay loam-2 sediments in the column was
 alkalized to ~12. *“Gamma-rays” clay loam-3 columns: the clay loam-3
 column was treated by gamma radiation. 4\. Reaction time point：0 d 5\.
 Variables description: \* EDC: refers to electron donating capacity.     *
 Fe(II): refers to iron(II). 6\. Specialized formats or other abbreviations
 used: None
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: DifferentTextures_EDC.xlsx 1\. Number of
 data titles: 11 2\. Number of sheets: 4 3\. Experimental systems： \* sand
 column (treated by HgCl2 + NaN3): the sand loams in the column were
 immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling. \* silt
 column (treated by HgCl2 + NaN3): the silt loams in the column were
 immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling. \* clay
 loam-1 column (treated by HgCl2 + NaN3): the clay loam-1 sediments in the
 column were immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling.
 \* clay loam-1 column (inclusion of sand): the clay loam-1 column (treated
 by HgCl2 + NaN3) was filled with inclusion of sand at the interface. 4\.
 Reaction time point：0 d, 8 d, 14 d, 24 d 5\. Variables description: \*
 EDC: refers to electron donating capacity. \* DEDC: refers to variation of
 electron donating capacity (EDC). 6\. Specialized formats or other
 abbreviations used: None
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: DifferentTextures_Fe(II).xlsx 1\. Number of
 data titles: 6 2\. Number of sheets: 3 3\. Experimental systems： \* silt
 column (treated by HgCl2 + NaN3): the silt loams in the column were
 immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling. \* clay
 loam-1 column (treated by HgCl2 + NaN3): the clay loam-1 sediments in the
 column were immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling.
 \* clay loam-1 column (inclusion of sand): the clay loam-1 column (treated
 by HgCl2 + NaN3) was filled with inclusion of sand at the interface. 4\.
 Reaction time point：0 d, 8 d, 14 d, 24 d 5\. Variables description: \*
 Fe(II): refers to iron(II). \* DFe(II): refers to variation of iron(II).
 6\. Specialized formats or other abbreviations used: None
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: DifferentSterilized_EDC.xlsx 1\. Number of
 data titles: 10 2\. Number of sheets: 4 3\. Experimental systems： \*
 untreated clay loam-1 columns: the clay loam-1 column with no treatment.
 \* autoclaved clay loam-1 columns: the clay loam-1 sediments in the column
 were autoclaved prior to filling. *“Gamma-rays” clay loam-3 columns: the
 clay loam-3 column was treated by gamma radiation. \* clay loam-1 column
 (inclusion of 1-cm sterilized): the clay loam-1 column (treated by HgCl2 +
 NaN3) was with inclusion of a 1-cm thick clay loam-1 interlayer treated by
 concentrated HgCl2 + NaN3 above or below the interface 4\. Reaction time
 point：0 d, 8 d, 14 d, 24 d 5\. Variables description: \* EDC: refers to
 electron donating capacity. \* DEDC: refers to variation of electron
 donating capacity (EDC). 6\. Specialized formats or other abbreviations
 used: None
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: DifferentSterilized_FeII.xlsx 1\. Number of
 data titles: 8 2\. Number of sheets: 4 3\. Experimental systems： \*
 untreated clay loam-1 columns: the clay loam-1 column with no treatment.
 \* autoclaved clay loam-1 columns: the clay loam-1 sediments in the column
 were autoclaved prior to filling. *“Gamma-rays” clay loam-3 columns: the
 clay loam-3 column was treated by gamma radiation. \* clay loam-1 column
 (inclusion of 1-cm sterilized): the clay loam-1 column (treated by HgCl2 +
 NaN3) was with inclusion of a 1-cm thick clay loam-1 interlayer treated by
 concentrated HgCl2 + NaN3 above or below the interface 4\. Reaction time
 point：0 d, 8 d, 14 d, 24 d 5\. Variables description: \* Fe(II): refers to
 iron(II). \* DFe(II): refers to variation of iron(II). 6\. Specialized
 formats or other abbreviations used: None
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: DifferentPerturbated_EDC.xlsx 1\. Number of
 data titles: 11 2\. Number of sheets: 5 3\. Experimental systems： \*
 untreated clay loam-2 columns: the clay loam-2 column with no treatment.
 \* O2-perturbated clay loam-1 columns: the clay loam-1 column was treated
 by O2-perturbation. *“Low temperature” clay loam-2 columns: the clay
 loam-2 column was treated by low temperature. *“Acid perturbation” clay
 loam-2 columns: the initial pH of clay loam-2 sediments in the column was
 acidified to ~4. *“Base perturbation” clay loam-2 columns: the initial pH
 of clay loam-2 sediments in the column was alkalized to ~12. 4\. Reaction
 time point：0 d, 8 d, 14 d, 24 d 5\. Variables description: \* EDC: refers
 to electron donating capacity. \* DEDC: refers to variation of electron
 donating capacity (EDC).
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: Sterilized_Pertuated_DissolvedSpecies.xlsx
 1\. Number of data titles: 3 2\. Number of sheets: 3 3\. Experimental
 systems： \* oxidized clay loam-2 suspensions (Untreated): 500 g/L of
 oxidized clay loam-2 suspensions with no treatment. \* oxidized clay
 loam-2 suspensions (“HgCl2 + NaN3”): the oxidized clay loam-2 sediments in
 the 500 g/L of suspension were treated by 250 mg/L HgCl2 and 500 mg/L
 NaN3. \* oxidized clay loam-2 suspensions (“Concentrated HgCl2 + NaN3”):
 the oxidized clay loam-2 sediments in the 500 g/L of suspension were
 treated by concentrated HgCl2 (1 g/L) and NaN3 (9.75 g/L). \* oxidized
 clay loam-2 suspensions (“Autoclaved”): the oxidized clay loam-2 sediments
 in the 500 g/L of suspension were treated by autoclavation. \* oxidized
 clay loam-2 suspensions (“Gamma-rays”): the oxidized clay loam-2 sediments
 in the 500 g/L of suspension were treated by gamma radiation. \* oxidized
 clay loam-2 suspensions (“Acid perturbation”): the oxidized clay loam-2
 sediments in the 500 g/L of suspension were treated by dilute H2SO4. \*
 oxidized clay loam-2 suspensions (“Base perturbation”): the oxidized clay
 loam-2 sediments in the 500 g/L of suspension were treated by dilute NaOH.
 \* oxidized clay loam-2 suspensions (“Low temperature”): the oxidized clay
 loam-2 sediments in the 500 g/L of suspension were treated by gamma
 radiation. 4\. Reaction time point：0 d, 8 d, 14 d, 24 d 5\. Variables
 description: \* DOC: refers to dissolved organic matter. \* dissolved
 total Fe: refers to total Fe in the aqueous phase of suspension.     *
 dissolved Fe(II): refers to Fe(II) in the aqueous phase of suspension. 6\.
 Specialized formats or other abbreviations used: None
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: SedimentPoreWater_EDCandEAC.xlsx 1\. Number
 of data titles: 12 2\. Number of sheets: 2 3\. Experimental systems： \*
 sand column (treated by HgCl2 + NaN3): the sand loams in the column were
 immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling. \* silt
 column (treated by HgCl2 + NaN3): the silt loams in the column were
 immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling. \* clay
 loam-1 column (treated by HgCl2 + NaN3): the clay loam-1 sediments in the
 column were immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling.
 4\. Reaction time point：0 d 5\. Variables description: \* water-extracted
 EDC value: the sediment samples in the column were mixed with water and
 then separated the water. The dissolved EDC value was measured as
 water-extracted EDC value. \* estimated EDC value: refers to the EDC value
 in the sediment pore which was calculated by converting the
 water-extracted EDC value based on the dilution factor and water content
 of sample. \* water-extracted EAC value: the sediment samples in the
 column were mixed with water and then separated the water. The dissolved
 EAC value was measured as water-extracted EDC value. \* estimated EAC
 value: refers to the EAC value in the sediment pore which was calculated
 by converting the water-extracted EAC value based on the dilution factor
 and water content of sample. 6\. Specialized formats or other
 abbreviations used: None
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: Gamma_DissolvedSpecies.xlsx 1\. Number of
 data titles: 8 2\. Number of sheets: 4 3\. Experimental systems：
 *“Gamma-rays” clay loam-3 columns: the clay loam-3 column was treated by
 gamma radiation. 4\. Reaction time point：0 d, 24 d 5\. Variables
 description: \* water-extracted DOC: the sediment samples in the column
 were mixed with water and then separated the water. The DOC value was
 measured as water-extracted DOC value. \* estimated DOC: refers to the DOC
 concentration in the sediment pore which was calculated by converting the
 water-extracted DOC concentration based on the dilution factor and water
 content of sample. \* water-extracted dissolved total Fe: the sediment
 samples in the column were mixed with water and then separated the water.
 The dissolved total Fe concentration was measured as water-extracted
 dissolved total Fe concentration. \* estimated dissolved total Fe: refers
 to the dissolved total Fe concentration in the sediment pore which was
 calculated by converting the water-extracted dissolved total Fe
 concentration based on the dilution factor and water content of sample. \*
 water-extracted dissolved Fe(II): the sediment samples in the column were
 mixed with water and then separated the water. The dissolved Fe(II)
 concentration was measured as water-extracted dissolved Fe(II)
 concentration. \* estimated dissolved Fe(II): refers to the dissolved
 Fe(II) concentration in the sediment pore which was calculated by
 converting the water-extracted dissolved Fe(II) concentration based on the
 dilution factor and water content of sample. \* water-extracted EDC value:
 the sediment samples in the column were mixed with water and then
 separated the water. The dissolved EDC value was measured as
 water-extracted EDC value. \* estimated EDC value: refers to the EDC value
 in the sediment pore which was calculated by converting the
 water-extracted EDC value based on the dilution factor and water content
 of sample. \* water-extracted EAC value: the sediment samples in the
 column were mixed with water and then separated the water. The dissolved
 EAC value was measured as water-extracted EDC value. \* estimated EAC
 value: refers to the EAC value in the sediment pore which was calculated
 by converting the water-extracted EAC value based on the dilution factor
 and water content of sample. 6\. Specialized formats or other
 abbreviations used: None
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: XRD.xlsx 1\. Number of data titles: 2 2\.
 Number of sheets: 2 3\. Samples： \* pristine reduced clay loam \* pristine
 reduced silt loam \* pristine reduced sand loam \* clay loam-1 samples
 near the oxidized/reduced interface (locations at 1.3 and -1.3 cm) in the
 clay loam-1 column treated by 250 mg/L HgCl2 and 500 mg/L NaN3. 4\.
 Reaction time point：0 d 5\. Specialized formats or other abbreviations
 used: None
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: EDC_Feasibility.xlsx 1\. Number of data
 titles: 10 2\. Number of sheets: 4 3\. Experimental systems： \* oxidized
 clay loam-1 suspension: the oxidized clay loam-1 suspensions at the dosage
 of 200, 400 and 600 g/L. \* reduced clay loam-1 suspension: the reduced
 clay loam-1 suspensions at the dosage of 200, 400 and 600 g/L. \* mixed
 clay loam-1 suspension: The mixture of oxidized and reduced clay loam-1 at
 the dosage of 200 g/L. \* oxidized clay loam-2 suspension: the oxidized
 clay loam-2 suspensions at the dosage of 200 g/L. \* high initial △Eh of
 clay loam-2 + clay loam-1 columns (treated by HgCl2 + NaN3): this column
 refers to the bottom half filled with reduced clay loam-1 and the upper
 half filled with oxidized clay loam-2. Both clay loam-1 and clay loam-2
 sediments in the column were immersed in 250 mg/L HgCl2 and 500 mg/L NaN3
 prior to filling. \* clay loam-2 + clay loam-1 columns with inclusion of
 quartz sand: this column refers to the bottom half filled with reduced
 clay loam-1 and the upper half filled with oxidized clay loam-2, with
 inclusion of 1-cm thick of quartz sand in the interface. Both clay loam-1
 and clay loam-2 sediments in the column were immersed in 250 mg/L HgCl2
 and 500 mg/L NaN3 prior to filling. 4\. Reaction time point：0 d, 4 d, 8 d,
 14 d, 24 d 5\. Variables description: \* EDC: refers to electron donating
 capacity. \* DEDC: refers to variation of electron donating capacity
 (EDC). 6\. Specialized formats or other abbreviations used: None
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: RNA_based_16S rRNA_genes.xlsx 1\. Number of
 data titles: 1 2\. Number of sheets: 1 3\. Experimental systems： \*
 oxidized clay loam-2 suspensions (Untreated): 500 g/L of oxidized clay
 loam-2 suspensions with no treatment. \* oxidized clay loam-2 suspensions
 (“HgCl2 + NaN3”): the oxidized clay loam-2 sediments in the 500 g/L of
 suspension were treated by 250 mg/L HgCl2 and 500 mg/L NaN3. \* oxidized
 clay loam-2 suspensions (“Concentrated HgCl2 + NaN3”): the oxidized clay
 loam-2 sediments in the 500 g/L of suspension were treated by concentrated
 HgCl2 (1 g/L) and NaN3 (9.75 g/L). \* oxidized clay loam-2 suspensions
 (“Autoclaved”): the oxidized clay loam-2 sediments in the 500 g/L of
 suspension were treated by autoclavation. \* oxidized clay loam-2
 suspensions (“Gamma-rays”): the oxidized clay loam-2 sediments in the 500
 g/L of suspension were treated by gamma radiation. \* oxidized clay loam-2
 suspensions (“Acid perturbation”): the oxidized clay loam-2 sediments in
 the 500 g/L of suspension were treated by dilute H2SO4. \* oxidized clay
 loam-2 suspensions (“Base perturbation”): the oxidized clay loam-2
 sediments in the 500 g/L of suspension were treated by dilute NaOH. \*
 oxidized clay loam-2 suspensions (“Low temperature”): the oxidized clay
 loam-2 sediments in the 500 g/L of suspension were treated by gamma
 radiation. 4\. Reaction time point：0 d 5\. Variables description: \* EDC:
 refers to electron donating capacity.     * Fe(II): refers to iron(II).
 6\. Specialized formats or other abbreviations used: None
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR:
 AmpliconSequenceAnalysis_MicrobialCommunity.xlsx 1\. Number of data
 titles: 1 2\. Number of sheets: 1 3\. Experimental systems： \* clay loam-1
 column (treated by HgCl2 + NaN3): the clay loam-1 sediments in the column
 were immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling. \*
 clay loam-1 column (inclusion of 1-cm sterilized): the clay loam-1 column
 (treated by HgCl2 + NaN3) was with inclusion of a 1-cm thick clay loam-1
 interlayer treated by concentrated HgCl2 + NaN3 above or below the
 interface 4\. Reaction time point：0 d, 8 d, 24 d 5\. Variables
 description: \* distribution of microbial community at genus-level. 6\.
 Specialized statement: Sequence data are available in NCBI (BioProject
 PRJNA949398).
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: ETflux_CalculationData.xlsx 1\. Number of
 data titles: 7 2\. Number of sheets: 6 3\. Experimental systems： \* clay
 loam-1 column (treated by HgCl2 + NaN3): the clay loam-1 sediments in the
 column were immersed in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling.
 \* untreated clay loam-1 columns: the clay loam-1 column with no
 treatment. \* autoclaved clay loam-1 columns: the clay loam-1 sediments in
 the column were autoclaved prior to filling. \* O2-perturbated clay loam-1
 columns: the clay loam-1 column was treated by O2-perturbation. \*
 untreated clay loam-2 columns: the clay loam-2 column with no treatment.
 *“Low temperature” clay loam-2 columns: the clay loam-2 column was treated
 by low temperature. *“Acid perturbation” clay loam-2 columns: the initial
 pH of clay loam-2 sediments in the column was acidified to ~4. *“Base
 perturbation” clay loam-2 columns: the initial pH of clay loam-2 sediments
 in the column was alkalized to ~12. *“Gamma-rays” clay loam-3 columns: the
 clay loam-3 column was treated by gamma radiation. 4\. Reaction time
 point：0 d, 8 d, 14 d, 24 d 5\. Variables description: \* ET flux: refers
 to the sum of DEDC in the whole reduced half or oxidized half. 6\.
 Specialized formats or other abbreviations used: None
 \#########################################################################
 DATA-SPECIFIC INFORMATION FOR: PerturbatedColumns_pH.xlsx 1\. Number of
 data titles: 1 2\. Number of sheets: 1 3\. Experimental systems： *“Acid
 perturbation” clay loam-2 columns: the initial pH of clay loam-2 sediments
 in the column was acidified to ~4. *“Base perturbation” clay loam-2
 columns: the initial pH of clay loam-2 sediments in the column was
 alkalized to ~12. 4\. Reaction time point：0 d, 8 d, 14 d, 24 d 5\.
 Variables description: \* pH: refers to pH of sediment samples in the
 column. 6\. Specialized formats or other abbreviations used: None
 \#########################################################################
 Detailed Descriptions: For a comprehensive understanding of the
 experimental setup and procedures, refer to the associated research paper.
 Proper citation and acknowledgment details are available in the original
 paper.