Properties of dissolved and total organic matter in throughfall, stemflow and forest floor leachate of Central European forests

Abstract

Abstract. For the first time, we investigated the composition of dissolved organic matter (DOM) compared to total OM (TOM, consisting of DOM and particulate OM, POM) in throughfall, stemflow and forest floor leachate of beech and spruce forests using solid state 13C nuclear magnetic resonance spectroscopy. We hypothesized that the composition and properties of OM in forest ecosystem water samples differed between DOM and TOM and between the two tree species. Under beech, a contribution of phyllosphere-derived fresh POM was echoed in structural differences. Compared with DOM, TOM exhibited higher relative intensities for the alkyl C region, representing aliphatic C from less decomposed organic material, and lower relative intensities for lignin-derived and aromatic C of the aryl C region, resulting in lower aromaticity indices and reduced humification intensities. Since differences in the structural composition of DOM and TOM were less pronounced under spruce than under beech, we suspect a~tree species-related effect on the origin of OM composition and resulting properties (e.g. recalcitrance, allelopathic potential).

DOC Transport and Export in a Dynamic Tropical Catchment

“…DOC pools are denoted from S1 to S7. Although SOC (including litter leachate) near the riparian areas constitutes the main carbon pool in headwater tropical catchments, organic matter from throughfall (1‐61 mg/L) and stemflow (7‐482 mg/L; often stored and released from mosses, ferns, lichens, and bromeliads) may also contribute a significant DOC pulse during large rain events (Bischoff et al, ; da Costa et al, ; Van Stan & Stubbins, ) to the overall fluvial carbon budget.…”

A review and evaluation of forest canopy epiphyte roles in the partitioning and chemical alteration of precipitation

“…The authors are also unaware of any studies regarding POM flux or structure in epiphyte-derived net precipitation, although this can represent a large part of the C and N throughfall flux to soils (Lamersdorf and Blank, 1995). As measurement techniques to address this gap exist, we recommend that future research utilize existing OM quantification and characterization methods (e.g., UV-vis absorbance spectral metrics (Helms et al, 2008), Fluorescence EEMS-based PARAFAC models (Stedmon and Bro, 2008), Solid state 13C nuclear magnetic resonance spectroscopy (Bischoff et al, 2015), and FTICR mass spectrometry (Stubbins et al, 2014)), as the quantity and character of organic matter inputs to beneath canopies is of, arguably, equal criticality to biogeochemical cycling in forest litter and soils as ionic macro-and micro-nutrients.…”

Role of natural organic matter on iodine and 239,240Pu distribution and mobility in environmental samples from the northwestern Fukushima Prefecture, Japan

“…Not only did the quantity of rainwater DOC change after it intercepted with the canopy, but the chemical properties and compositions of the organic matter were also altered, driven by various abiotic and biotic processes. For example, the aromaticity and humification indices of both deciduous and coniferous throughfall and stemflow increased significantly compared to the bulk deposition, suggesting that organic matter in the forest throughfall and stemflow solutions contains more aromatics and refractory condensed aromatics (Bischoff et al, 2015;Lv et al, 2014). Aromatics likely then scavenged iodine through electrophilic substitution via abiotic and enzymatic pathways (Xu, C. et al, 2013;Xu et al, 2011b;Xu et al, 2012).…”