| 33586 |
Creator |
9afccdbe975e25965953e777bb4d6a5f |
| 33586 |
Creator |
a83b960ddf2843a8567430721dcd0f08 |
| 33586 |
Creator |
ext-c6b96429afd8bdb9a48beba68d34e94c |
| 33586 |
Date |
2003-04 |
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Is Part Of |
repository |
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abstract |
It is well known that volcanic gases can pollute the atmosphere. Certain volcanic
gases can produce biogeochemical effects that lead to an indirect volcanic effect
on the atmosphere. Microbially mediated emission of CH<sub>4</sub> from wetlands can
be reduced as a result of SO<sub>4</sub>-- deposition by stimulating competitive exclusion
of methanogens by sulfate reducing microorganisms. Hence, a large emission of volcanic
SO<sub>2</sub> could lead to a fall in atmospheric CH<sub>4</sub>. We have developed
a simple mathematical model to explore the effects of the Icelandic Laki eruption
that occurred in 1783 and compare the results with ice-core records of late 18th century
atmospheric methane. Field experiments have shown that methane emission rates are
suppressed for at least 2 years after a short episode of S deposition which is likely
due to reoxidation of reduced sulfur compounds back to SO<sub>4</sub>-- at steep redox
gradients that exist within wetlands. Using Stevenson et al.'s (2003) model, we estimate
a reduction in methane emission from northern wetlands of ca. 10 Tg/year (a 6 percent
reduction). Our model predicts a decrease in the mean global atmospheric methane concentration
of up to 5 ppbv (0.7 percent) and a c. 15 year period of lowered methane. Ice-core
data (Etheridge et al., 1998) show a possible dip in atmospheric methane growth rate
at the correct time, but a fuller comparison is compromised by the coarseness of the
record. Our study suggests that basaltic eruptions that are at least the size and
duration of Laki can induce a measurable reduction in atmospheric methane. |
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authorList |
authors |
| 33586 |
presentedAt |
ext-083caf7f96a70cc1ed678d3503213ebe |
| 33586 |
status |
peerReviewed |
| 33586 |
type |
AcademicArticle |
| 33586 |
type |
Article |
| 33586 |
label |
Gauci, V. ; Blake, S. and Stevenson, D. (2003). Volcanic influences on the atmospheric
methane budget. In: EGS - AGU - EUG Joint Assembly, 6-11 Apr 2003, Nice, France.
|
| 33586 |
label |
Gauci, V. ; Blake, S. and Stevenson, D. (2003). Volcanic influences on the atmospheric
methane budget. In: EGS - AGU - EUG Joint Assembly, 6-11 Apr 2003, Nice, France. |
| 33586 |
Title |
Volcanic influences on the atmospheric methane budget |
| 33586 |
in dataset |
oro |