Characterisation and reactivity continuum of dissolved organic matter in forested headwater catchments of Andean Patagonia

2018 ◽  
Vol 63 (9) ◽  
pp. 1049-1062 ◽  
Author(s):  
Roberto Daniel Garcia ◽  
María del Carmen Diéguez ◽  
Marina Gerea ◽  
Patricia Elizabeth Garcia ◽  
Mariana Reissig
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Headwater Catchments ◽  
Reactivity Continuum

scholarly journals Seasonal hydrology and permafrost disturbance impacts on dissolved organic matter composition in High Arctic headwater catchments

2017 ◽  
Vol 3 (2) ◽  
pp. 378-405 ◽  
Author(s):  
J. Fouché ◽  
M. J. Lafrenière ◽  
K. Rutherford ◽  
S. Lamoureux
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Active Layer ◽  
Climate Change Impacts ◽  
High Arctic ◽  
Low Molecular Weight ◽  
Headwater Catchments ◽  
Precipitation Regimes ◽  
Spring Freshet

Arctic landscapes are experiencing intense warming and modification of precipitation regimes with climate change. Permafrost disturbances and climate change impacts on hydrology of Arctic watersheds are likely to modify the quantity and composition of exported dissolved organic matter (DOM). In July 2007, intense rainfall and active layer thickening caused widespread active layer detachments at Cape Bounty, Melville Island (Canada). This study investigates the impacts of seasonal hydrology and permafrost disturbance on DOM composition exported from High Arctic headwater catchments. In 2012, streams were sampled from three disturbed catchments and one undisturbed catchment. The composition of DOM was characterized using absorbance and fluorescence spectroscopy. DOM was mostly exported during the spring freshet. Throughout this period, the undisturbed catchment exported humified DOM with high humic-like fluorescence that likely originated from runoff through shallow organic rich soil. In contrast, DOM exported from disturbed catchments was fresher, less humified with a high proportion of low molecular weight humic acid. We demonstrate that disturbed catchments delivered likely more labile DOM derived from either thawed permafrost or enhanced microbial activity. If this labile DOM comes from an ancient pool, as indicated by other studies at this site, disturbances may strengthen the permafrost carbon feedback on climate change.

scholarly journals Effects of compositional changes on reactivity continuum and decomposition kinetics of lake dissolved organic matter

2016 ◽  
Vol 121 (7) ◽  
pp. 1733-1746 ◽  
Author(s):  
Alina Mostovaya ◽  
Birgit Koehler ◽  
François Guillemette ◽  
Anna-Kristina Brunberg ◽  
Lars J. Tranvik
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Decomposition Kinetics ◽  
Compositional Changes ◽  
Kinetics Of ◽  
Reactivity Continuum
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