scholarly journals Carbon Inputs From Riparian Vegetation Limit Oxidation of Physically Bound Organic Carbon Via Biochemical and Thermodynamic Processes

2017 ◽  
Vol 122 (12) ◽  
pp. 3188-3205 ◽  
Author(s):  
Emily B. Graham ◽  
Malak M. Tfaily ◽  
Alex R. Crump ◽  
Amy E. Goldman ◽  
Lisa M. Bramer ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Riparian Vegetation ◽  
Thermodynamic Processes

scholarly journals Carbon inputs from riparian vegetation limit oxidation of physically-bound organic carbon via biochemical and thermodynamic processes

2017 ◽  
Author(s):  
Emily B. Graham ◽  
Malak Tfaily ◽  
Alex R. Crump ◽  
Amy E. Goldman ◽  
Lisa Bramer ◽  
...  
Keyword(s):  
High Resolution ◽  
Organic Carbon ◽  
Land Cover ◽  
Metabolic Pathways ◽  
Riparian Vegetation ◽  
Columbia River ◽  
Water Soluble ◽  
Future Climate ◽  
River Corridor ◽  
Thermodynamic Processes

In light of increasing terrestrial carbon (C) transport across aquatic boundaries, the mechanisms governing organic carbon (OC) oxidation along terrestrial-aquatic interfaces are crucial to future climate predictions. Here, we investigate the biochemistry, metabolic pathways, and thermodynamics corresponding to OC oxidation in the Columbia River corridor using ultra-high resolution C characterization. We leverage natural vegetative differences to encompass variation in terrestrial C inputs. Our results suggest that decreases in terrestrial C deposition associated with diminished riparian vegetation induce oxidation of physically-bound OC. We also find that contrasting metabolic pathways oxidize OC in the presence and absence of vegetation and -- in direct conflict with the priming concept -- that inputs of water-soluble and thermodynamically favorable terrestrial OC protects bound-OC from oxidation. In both environments, the most thermodynamically favorable compounds appear to be preferentially oxidized regardless of which OC pool microbiomes metabolize. In turn, we suggest that the extent of riparian vegetation causes sediment microbiomes to locally adapt to oxidize a particular pool of OC, but that common thermodynamic principles govern the oxidation of each pool (i.e., water-soluble or physically-bound). Finally, we propose a mechanistic conceptualization of OC oxidation along terrestrial-aquatic interfaces that can be used to model heterogeneous patterns of OC loss under changing land cover distributions.

Impact of Riparian and Stream Restoration on Denitrification in Geomorphic Features of Agricultural Streams

2020 ◽  
Vol 63 (5) ◽  
pp. 1157-1167
Author(s):  
Molly K. Welsh ◽  
Sara K. McMillan ◽  
Philippe G. Vidon
Keyword(s):  
Organic Matter ◽  
Enzyme Activity ◽  
Organic Carbon ◽  
Riparian Vegetation ◽  
Dry Mass ◽  
Residence Times ◽  
Sediment Texture ◽  
Agricultural Streams ◽  
Geomorphic Features ◽  
Restoration Strategies

HighlightsDenitrification enzyme activity (DEA) was measured in stream sediments of restored and unrestored agricultural streams.Nitrate, sediment characteristics, riparian vegetation, and geomorphology influenced DEA.Pools at restored sites had lower organic carbon, coarser sediment textures, and lower denitrification potential.Restoration strategies should increase organic carbon and residence times through complex flowpaths.Abstract. Agricultural land use, channel modifications, and riparian vegetation composition can affect instream denitrification by altering geomorphic features, such as sediment texture, organic matter, retention time, and hyporheic exchange. Stream and riparian restoration is widely implemented in agricultural watersheds to mitigate excess nutrient export to sensitive downstream waters; however, the cumulative impact of channel reconstruction and altered channel and near-stream morphology on nitrogen dynamics remains poorly understood. We measured denitrification enzyme activity (DEA) and environmental variables (e.g., water chemistry, sediment texture, and organic matter) in different geomorphic features in agriculturally influenced streams in North Carolina with varied channel and riparian zone characteristics. Our results indicate that denitrification is primarily influenced by increased transport of nitrate (NO3-) to the streams in wetter months. Secondarily, structural factors, including riparian vegetation and stream geomorphology, impact denitrification by controlling the distribution of sediment texture and organic carbon. In the newly restored stream, we observed coarser streambed sediments and low sediment organic carbon, especially in scour pools constructed downstream from cross-vanes. Lower DEA was observed in restored pools (39.1 ng N g-1 dry mass h-1) compared to naturally occurring pools (70.7 to 278.1 ng N g-1 dry mass h-1). These results highlight the need for restoration strategies to be directed at increasing organic carbon and residence times through complex flowpaths (e.g., meanders, root wads, artificial woody debris dams). Keywords: Denitrification, Freshwater, Nitrogen, Restoration, Riparian, Stream, Water quality.

Effects of riparian vegetation on soil organic carbon and total nitrogen distribution — a case study of Wenyu River, Beijing

2013 ◽  
Vol 20 (10) ◽  
pp. 1315-1321
Author(s):  
Er-Hui GUO ◽  
Ran-Hao SUN ◽  
Li-Ding CHEN ◽  
Zhao-Ming WANG ◽  
Jun XIAO ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Total Nitrogen ◽  
Riparian Vegetation ◽  
Nitrogen Distribution

Deployable Decentralized Biofilm System to Degrade Organic Carbon, Nutrients and Benzene from Wastewater

2009 ◽  
Author(s):  
Dong Chen ◽  
Che-Jen Lin ◽  
R. Gavin Jones ◽  
Sehul Patel ◽  
Rachelle Smith ◽  
...  
Keyword(s):  
Organic Carbon

Photocatalytic degradation of methylene blue from aqueous solutions using nanopillars-TiO2 thin films: Batch reactor studies

2018 ◽  
Vol 18 (3) ◽  
pp. 81-91 ◽  
Author(s):  
C. Lalhriatpuia
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Organic Carbon ◽  
Photocatalytic Degradation ◽  
Batch Reactor ◽  
Tio2 Thin Films ◽  
Initial Concentration ◽  
Bet Specific Surface Area ◽  
Interfering Ions

Nanopillars-TiO2 thin films was obtained on a borosilicate glass substrate with (S1) and without (S2) polyethylene glycol as template. The photocatalytic behaviour of S1 and S2 thin films was assessed inthe degradation of methylene blue (MB) dye from aqueous solution under batch reactor operations. The thin films were characterized by the SEM, XRD, FTIR and AFM analytical methods. BET specific surface area and pore sizes were also obtained. The XRD data confirmed that the TiO2 particles are in its anatase mineral phase. The SEM and AFM images indicated the catalyst is composed with nanosized pillars of TiO2, evenly distributed on the surface of the substrate. The BET specific surface area and pore sizes of S1 and S2 catalyst were found to be 5.217 and 1.420 m2/g and 7.77 and 4.16 nm respectively. The photocatalytic degradation of MB was well studied at wide range of physico-chemical parameters. The effect of solution pH (pH 4.0 to 10.0) and MB initial concentration (1.0 to 10.0 mg/L) was extensively studied and the effect of several interfering ions, i.e., cadmium nitrate, copper sulfate, zinc chloride, sodium chloride, sodium nitrate, sodium nitrite, glycine, oxalic acid and EDTA in the photocatalytic degradation of MB was demonstrated. The maximum percent removal of MB was observed at pH 8.0 beyond which it started decreasing and a low initial concentration of the pollutant highly favoured the photocatalytic degradation using thin films and the presence of several interfering ions diminished the photocatalytic activity of thin films to some extent. The overall photocatalytic activity was in the order: S2 > S1 > UV. The photocatalytic degradation of MB was followed the pseudo-first-order rate kinetics. The mineralization of MB was studied with total organic carbon measurement using the TOC (total organic carbon) analysis.

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