Peat deformation and biogenic gas bubbles control seasonal variations in peat hydraulic conductivity

Research output: Contribution to journalArticle

Standard

Peat deformation and biogenic gas bubbles control seasonal variations in peat hydraulic conductivity. / Kettridge, Nicholas; Kellner, Erik; Price, Jon; Waddington, James Michael.

In: Hydrological Processes, Vol. 27, No. 22, 30.10.2013, p. 3208-3216.

Research output: Contribution to journalArticle

Harvard

APA

Vancouver

Author

Kettridge, Nicholas ; Kellner, Erik ; Price, Jon ; Waddington, James Michael. / Peat deformation and biogenic gas bubbles control seasonal variations in peat hydraulic conductivity. In: Hydrological Processes. 2013 ; Vol. 27, No. 22. pp. 3208-3216.

Bibtex

@article{041e49f7460843528549437b99c17bae,
title = "Peat deformation and biogenic gas bubbles control seasonal variations in peat hydraulic conductivity",
abstract = "The hydraulic conductivity (K) of peat beneath the water table varies over short (annual) periods. Biogenic gas bubbles block pores and reduce K, and seasonal changes in the water table position cause peat deformation, altering peat pore size distribution. Although it has been hypothesized that both processes reduce K during warm dry summer conditions, temporal variations in K under field conditions have been explained previously by peat volume changes (strain) alone. We determine the effect of both controls on K by monitoring changes in gas content (Δγ), strain and K within a poor fen. Over the growing season, K decreased by an order of magnitude. In the near-surface peat (0.3-0.7m), this reduction is more strongly correlated with Δγ, providing the first field-based evidence that biogenic gas bubbles reduce K. In the deeper peat (0.7-1.3m), K is correlated principally with strain. However, causality is uncertain because of multicollinearity between strain and Δγ. To mitigate for multicollinearity, we took advantage of a peatland drainage experiment where the water table was artificially dropped at the beginning of the growing season, reducing correlations between strain and Δγ. Δγ remained the primary cause of K variations just beneath the water table at a depth of 0.5-0.7m, although further down through the peat profile (0.7-1.2m) changes in K were controlled by strain. We suggest that the larger pore structure of the poorly decomposed peat just below the water table is impacted less by volume changes than that of the more decomposed peat at depth. However, within this poorly decomposed peat, K is reduced by the high gas contents that result from higher rates of methane production.",
keywords = "Deformation, Gas bubbles, Hydraulic conductivity, Methane, Peat",
author = "Nicholas Kettridge and Erik Kellner and Jon Price and Waddington, {James Michael}",
year = "2013",
month = oct,
day = "30",
doi = "10.1002/hyp.9369",
language = "English",
volume = "27",
pages = "3208--3216",
journal = "Hydrological Processes",
issn = "0885-6087",
publisher = "Wiley",
number = "22",

}

RIS

TY - JOUR

T1 - Peat deformation and biogenic gas bubbles control seasonal variations in peat hydraulic conductivity

AU - Kettridge, Nicholas

AU - Kellner, Erik

AU - Price, Jon

AU - Waddington, James Michael

PY - 2013/10/30

Y1 - 2013/10/30

N2 - The hydraulic conductivity (K) of peat beneath the water table varies over short (annual) periods. Biogenic gas bubbles block pores and reduce K, and seasonal changes in the water table position cause peat deformation, altering peat pore size distribution. Although it has been hypothesized that both processes reduce K during warm dry summer conditions, temporal variations in K under field conditions have been explained previously by peat volume changes (strain) alone. We determine the effect of both controls on K by monitoring changes in gas content (Δγ), strain and K within a poor fen. Over the growing season, K decreased by an order of magnitude. In the near-surface peat (0.3-0.7m), this reduction is more strongly correlated with Δγ, providing the first field-based evidence that biogenic gas bubbles reduce K. In the deeper peat (0.7-1.3m), K is correlated principally with strain. However, causality is uncertain because of multicollinearity between strain and Δγ. To mitigate for multicollinearity, we took advantage of a peatland drainage experiment where the water table was artificially dropped at the beginning of the growing season, reducing correlations between strain and Δγ. Δγ remained the primary cause of K variations just beneath the water table at a depth of 0.5-0.7m, although further down through the peat profile (0.7-1.2m) changes in K were controlled by strain. We suggest that the larger pore structure of the poorly decomposed peat just below the water table is impacted less by volume changes than that of the more decomposed peat at depth. However, within this poorly decomposed peat, K is reduced by the high gas contents that result from higher rates of methane production.

AB - The hydraulic conductivity (K) of peat beneath the water table varies over short (annual) periods. Biogenic gas bubbles block pores and reduce K, and seasonal changes in the water table position cause peat deformation, altering peat pore size distribution. Although it has been hypothesized that both processes reduce K during warm dry summer conditions, temporal variations in K under field conditions have been explained previously by peat volume changes (strain) alone. We determine the effect of both controls on K by monitoring changes in gas content (Δγ), strain and K within a poor fen. Over the growing season, K decreased by an order of magnitude. In the near-surface peat (0.3-0.7m), this reduction is more strongly correlated with Δγ, providing the first field-based evidence that biogenic gas bubbles reduce K. In the deeper peat (0.7-1.3m), K is correlated principally with strain. However, causality is uncertain because of multicollinearity between strain and Δγ. To mitigate for multicollinearity, we took advantage of a peatland drainage experiment where the water table was artificially dropped at the beginning of the growing season, reducing correlations between strain and Δγ. Δγ remained the primary cause of K variations just beneath the water table at a depth of 0.5-0.7m, although further down through the peat profile (0.7-1.2m) changes in K were controlled by strain. We suggest that the larger pore structure of the poorly decomposed peat just below the water table is impacted less by volume changes than that of the more decomposed peat at depth. However, within this poorly decomposed peat, K is reduced by the high gas contents that result from higher rates of methane production.

KW - Deformation

KW - Gas bubbles

KW - Hydraulic conductivity

KW - Methane

KW - Peat

UR - http://www.scopus.com/inward/record.url?scp=84884988310&partnerID=8YFLogxK

U2 - 10.1002/hyp.9369

DO - 10.1002/hyp.9369

M3 - Article

AN - SCOPUS:84884988310

VL - 27

SP - 3208

EP - 3216

JO - Hydrological Processes

JF - Hydrological Processes

SN - 0885-6087

IS - 22

ER -