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Title: Elemental composition and optical properties reveal changes in dissolved organic matter along a permafrost thaw chronosequence in a subarctic peatland

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1328531
Grant/Contract Number:
SC0004632; SC0010580
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Geochimica et Cosmochimica Acta
Additional Journal Information:
Journal Volume: 187; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-03 21:14:37; Journal ID: ISSN 0016-7037
Publisher:
Elsevier
Country of Publication:
United States
Language:
English

Citation Formats

Hodgkins, Suzanne B., Tfaily, Malak M., Podgorski, David C., McCalley, Carmody K., Saleska, Scott R., Crill, Patrick M., Rich, Virginia I., Chanton, Jeffrey P., and Cooper, William T. Elemental composition and optical properties reveal changes in dissolved organic matter along a permafrost thaw chronosequence in a subarctic peatland. United States: N. p., 2016. Web. doi:10.1016/j.gca.2016.05.015.
Hodgkins, Suzanne B., Tfaily, Malak M., Podgorski, David C., McCalley, Carmody K., Saleska, Scott R., Crill, Patrick M., Rich, Virginia I., Chanton, Jeffrey P., & Cooper, William T. Elemental composition and optical properties reveal changes in dissolved organic matter along a permafrost thaw chronosequence in a subarctic peatland. United States. doi:10.1016/j.gca.2016.05.015.
Hodgkins, Suzanne B., Tfaily, Malak M., Podgorski, David C., McCalley, Carmody K., Saleska, Scott R., Crill, Patrick M., Rich, Virginia I., Chanton, Jeffrey P., and Cooper, William T. 2016. "Elemental composition and optical properties reveal changes in dissolved organic matter along a permafrost thaw chronosequence in a subarctic peatland". United States. doi:10.1016/j.gca.2016.05.015.
@article{osti_1328531,
title = {Elemental composition and optical properties reveal changes in dissolved organic matter along a permafrost thaw chronosequence in a subarctic peatland},
author = {Hodgkins, Suzanne B. and Tfaily, Malak M. and Podgorski, David C. and McCalley, Carmody K. and Saleska, Scott R. and Crill, Patrick M. and Rich, Virginia I. and Chanton, Jeffrey P. and Cooper, William T.},
abstractNote = {},
doi = {10.1016/j.gca.2016.05.015},
journal = {Geochimica et Cosmochimica Acta},
number = C,
volume = 187,
place = {United States},
year = 2016,
month = 8
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.gca.2016.05.015

Citation Metrics:
Cited by: 1work
Citation information provided by
Web of Science

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  • The fate of carbon stored in permafrost-zone peatlands represents a significant uncertainty in global climate modeling. Given that the breakdown of dissolved organic matter (DOM) is often a major pathway for decomposition in peatlands, knowledge of DOM reactivity under different permafrost regimes is critical for determining future climate feedbacks. To explore the effects of permafrost thaw and resultant plant succession on DOM reactivity, we used a combination of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), UV/Vis absorbance, and excitation-emission matrix spectroscopy (EEMS) to examine the DOM elemental composition and optical properties of 27 pore water samples gathered frommore » various sites along a permafrost thaw sequence in Stordalen Mire, a thawing subarctic peatland in northern Sweden. The presence of dense Sphagnum moss, a feature that is dominant in the intermediate thaw stages, appeared to be the main driver of variation in DOM elemental composition and optical properties at Stordalen. Specifically, DOM from sites with Sphagnum had greater aromaticity, higher average molecular weights, and greater O/C, consistent with a higher abundance of phenolic compounds that likely inhibit decomposition. These compounds are released by Sphagnum and may accumulate due to inhibition of phenol oxidase activity by the acidic pH at these sites. In contrast, sites without Sphagnum, specifically fully-thawed rich fens, had more saturated, more reduced compounds, which were high in N and S. Optical properties at rich fens were indicated the presence of microbially-derived DOM, consistent with the higher decomposition rates previously measured at these sites. These results indicate that Sphagnum acts as an inhibitor of rapid decomposition and CH4 release in thawing subarctic peatlands, consistent with lower rates of CO2 and CH4 production previously observed at these sites. However, this inhibitory effect may disappear if Sphagnumdominated bogs transition to more waterlogged rich fens that contain very little to no living Sphagnum. Release of this inhibition allows for higher levels of microbial activity and potentially greater CH4 release, as has been observed in these fen sites.« less
  • Cited by 9
  • Permafrost stores approximately 50% of global soil carbon (C) in a frozen form; it is thawing rapidly under climate change, and little is known about viral communities in these soils or their roles in C cycling. In permafrost soils, microorganisms contribute significantly to C cycling, and characterizing them has recently been shown to improve prediction of ecosystem function. In other ecosystems, viruses have broad ecosystem and community impacts ranging from host cell mortality and organic matter cycling to horizontal gene transfer and reprogramming of core microbial metabolisms. Here we developed an optimized protocol to extract viruses from three types ofmore » high organic-matter peatland soils across a permafrost thaw gradient (palsa, moss-dominated bog, and sedge-dominated fen). Three separate experiments were used to evaluate the impact of chemical buffers, physical dispersion, storage conditions, and concentration and purification methods on viral yields. The most successful protocol, amended potassium citrate buffer with bead-beating or vortexing and BSA, yielded on average as much as 2-fold more virus-like particles (VLPs) g –1of soil than other methods tested. All method combinations yielded VLPs g –1of soil on the 10 8order of magnitude across all three soil types. The different storage and concentration methods did not yield significantly more VLPs g –1of soil among the soil types. In conclusion, this research provides much-needed guidelines for resuspending viruses from soils, specifically carbon-rich soils, paving the way for incorporating viruses into soil ecology studies.« less