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| Titel |
Regional variation of natural peatland pool biogeochemistry and carbon concentrations |
| VerfasserIn |
Ed Turner, Mike Billett, Pippa Chapman, Andy Baird, Kerry Dinsmore, Joseph Holden |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250112518
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| Publikation (Nr.) |
 EGU/EGU2015-12677.pdf |
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| Zusammenfassung |
| Natural open-water pools are a common feature of northern peatlands. They are characterised
by low primary production, low pH, and often high concentrations of dissolved organic
carbon (DOC). Peatland pools are also sources of atmospheric CH4, and thus have the
potential to play an important role in global radiative forcing. Pool environmental variables,
particularly water chemistry, vegetation community and physical characteristics, have the
potential to exert strong controls on C cycling in pools; however, to our knowledge, no
existing studies have addressed the potential variation in pool biogeochemistry and physical
characteristics on a regional basis.
A total of 66 peatland pools were studied across three regions of the UK (northern
Scotland, south-west Scotland, and Northern Ireland) over the period September –
October 2013. Vegetation communities, mean depth and basic water chemistry
(pH, electrical conductivity and dissolved oxygen) were measured in situ. Water
samples were taken for analysis of DOC, POC, DIC, CH4diss, CO2diss(dissolved CO2
and CH4),total N and P, and Cl-, SO42- and NO3-. To evaluate the composition
of DOC, UV absorption was measured at 665, 470, 465, 436, 400, 360, 265, 254
nm.
We show that many pool variables are significantly different between regions, including
DOC, POC and CH4diss. The higher ratio of absorbance at 465 to absorbance at 665nm
(E4/E6) for pools in Northern Ireland indicates DOC was sourced from less humified peat,
which has implications for the bioavailability and mineralisation of organic carbon. Anion
concentrations were significantly higher in the pools in northern Scotland than elsewhere,
most likely due to a marine influence. SO42- is a CH4 electron acceptor and thus
concentrations may influence methanogenesis. Hierarchical cluster analysis shows
clear grouping of the individual pools within each region. PCA analysis showed
that pools in SW Scotland were strongly associated with greater vegetative cover
(Sphagnum, Eriophorum, algae) and shallower water depth, whereas pools in N
Scotland were more open and deeper, with Menyanthes trifoliata occurring more
frequently.
We discuss the implications of these results in the context of the role that pools play in
peatland carbon cycling. |
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