Sequestration of a Biologically Labile Organic Carbon in Soils by Humified Organic Matter

The "priming effect", in which addition of labile substances changes the remineralization rate of recalcitrant organic matter, has been intensively studied in soils, but is less well-documented in aquatic systems. We investigated the extent to which additions of nutrients or labile organic carbon could influence remineralization rates of 14C-labeled, microbially-degraded, phytoplankton-derived organic matter (OM) in microcosms inoculated with microbial communities drawn from Groves Creek Estuary in coastal Georgia, USA. We found that amendment with labile protein plus phosphorus increased remineralization rates of degraded, phytoplankton-derived OM by up to 100%, whereas acetate slightly decreased remineralization rates relative to an unamended control. Addition of ammonium and phosphate induced a smaller effect, whereas addition of ammonium alone had no effect. Counterintuitively, alkaline phosphatase activities increased in response to the addition of protein under P-replete conditions, indicating that production of enzymes unrelated to the labile priming compound may be a mechanism for the priming effect. The observed priming effect was transient: after 36 days of incubation roughly the same quantity of organic carbon had been mineralized in all treatments including no-addition controls. This timescale is on the order of the typical hydrologic residence times of well-flushed estuaries suggesting that priming in estuaries has the potential to influence whether OC is remineralized in situ or exported to the coastal ocean.

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Influence of Different Acid Treatments on the Radiocarbon Content Spectrum of Sedimentary Organic Matter Determined by RPO/Accelerator Mass Spectrometry

Radiocarbon ◽

10.1017/rdc.2018.125 ◽

2018 ◽

Vol 61 (2) ◽

pp. 395-413 ◽

Cited By ~ 9

Author(s):

Rui Bao ◽

Ann P McNichol ◽

Jordon D Hemingway ◽

Mary C Lardie Gaylord ◽

Timothy I Eglinton

Keyword(s):

Mass Spectrometry ◽

Organic Matter ◽

Organic Carbon ◽

Acid Treatment ◽

Inorganic Carbon ◽

River Sediments ◽

Labile Organic Carbon ◽

Underlying Causes ◽

High Carbonate ◽

Acid Treatments

ABSTRACTIn practice, obtaining radiocarbon (14C) composition of organic matter (OM) in sediments requires first removing inorganic carbon (IC) by acid-treatment. Two common treatments are acid rinsing and fumigation. Resulting14C content obtained by different methods can differ, but underlying causes of these differences remain elusive. To assess the influence of different acid-treatments on14C content of sedimentary OM, we examine the variability in14C content for a range of marine and river sediments. By comparing results for unacidified and acidified sediments [HCl rinsing (RinseHCl) and HCl fumigation (FumeHCl)], we demonstrate that the two acid-treatments can affect14C content differentially. Our findings suggest that, for low-carbonate samples, RinseHClaffects the Fm values due to loss of young labile organic carbon (OC). FumeHClmakes the Fm values for labile OC decrease, leaving the residual OC older. High-carbonate samples can lose relatively old organic components during RinseHCl, causing the Fm values of remaining OC to increase. FumeHClcan remove thermally labile, usually young, OC and reduce the Fm values. We suggest three factors should be taken into account when using acid to remove carbonate from sediments: IC abundance, proportions of labile and refractory OC, and environmental matrix.

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Organic matter mineralization in modern and ancient ferruginous sediments

Nature Communications ◽

10.1038/s41467-021-22453-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

André Friese ◽

Kohen Bauer ◽

Clemens Glombitza ◽

Luis Ordoñez ◽

Daniel Ariztegui ◽

...

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Methane Oxidation ◽

Methane Production ◽

Ferric Iron ◽

Biogeochemical Cycling ◽

Low Oxygen ◽

Labile Organic Carbon ◽

Organic Matter Mineralization ◽

Lake Towuti

AbstractDeposition of ferruginous sediment was widespread during the Archaean and Proterozoic Eons, playing an important role in global biogeochemical cycling. Knowledge of organic matter mineralization in such sediment, however, remains mostly conceptual, as modern ferruginous analogs are largely unstudied. Here we show that in sediment of ferruginous Lake Towuti, Indonesia, methanogenesis dominates organic matter mineralization despite highly abundant reactive ferric iron phases like goethite that persist throughout the sediment. Ferric iron can thus be buried over geologic timescales even in the presence of labile organic carbon. Coexistence of ferric iron with millimolar concentrations of methane further demonstrates lack of iron-dependent methane oxidation. With negligible methane oxidation, methane diffuses from the sediment into overlying waters where it can be oxidized with oxygen or escape to the atmosphere. In low-oxygen ferruginous Archaean and Proterozoic oceans, therefore, sedimentary methane production was likely favored with strong potential to influence Earth’s early climate.

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Effect of Municipal Sewage Sludge under Salix Plantations on Dissolved Soil Organic Carbon Pools / Wpływ Osadów Ściekowych Na Plantacjach Salix Na Zawartość Węgla Rozpuszczonego W Glebie

Archives of Environmental Protection ◽

10.2478/v10265-012-0030-8 ◽

2012 ◽

Vol 38 (4) ◽

pp. 87-97 ◽

Cited By ~ 3

Author(s):

Barbara Kalisz ◽

Andrzej Lachacz ◽

Roman Glazewski ◽

Andrzej Klasa

Keyword(s):

Organic Matter ◽

Sewage Sludge ◽

Organic Carbon ◽

Municipal Sewage ◽

Municipal Sewage Sludge ◽

Carbon Fractions ◽

Labile Organic Carbon ◽

Organic Carbon Fractions ◽

Soil Organic Carbon Pools ◽

One Year

Abstract Labile fractions of organic matter can rapidly respond to changes in soil and they have been suggested as sensitive indicators of soil organic matter. Two labile fractions of organic carbon in the soils amended with fresh municipal sewage sludge in two rates (equivalent of 60 kg P ha-1 and 120 kg P ha-1) were studied. Soils under studies were overgrown with Salix in Germany, Estonia and Poland. In Polish soils application of sewage sludge increased the content of both labile organic carbon fractions (KMnO4-C and HWC) for a period of one year. Estonian soils were stable and no distinct changes in labile organic carbon fractions occurred.

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Earth’s Middle Ages: What Came after the GOE

10.23943/princeton/9780691145020.003.0009 ◽

2017 ◽

Author(s):

Donald Eugene Canfield

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Middle Ages ◽

Atmospheric Oxygen ◽

Iron Formation ◽

Banded Iron Formation ◽

Dissolved Iron ◽

Great Oxidation Event ◽

Low Levels ◽

Substantial Rise

This chapter considers the aftermath of the great oxidation event (GOE). It suggests that there was a substantial rise in oxygen defining the GOE, which may, in turn have led to the Lomagundi isotope excursion, which was associated with high rates of organic matter burial and perhaps even higher concentrations of oxygen. This excursion was soon followed by a crash in oxygen to very low levels and a return to banded iron formation deposition. When the massive amounts of organic carbon buried during the excursion were brought into the weathering environment, they would have represented a huge oxygen sink, drawing down levels of atmospheric oxygen. There appeared to be a veritable seesaw in oxygen concentrations, apparently triggered initially by the GOE. The GOE did not produce enough oxygen to oxygenate the oceans. Dissolved iron was removed from the oceans not by reaction with oxygen but rather by reaction with sulfide. Thus, the deep oceans remained anoxic and became rich in sulfide, instead of becoming well oxygenated.

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Content and seasonal change in soil labile organic carbon under different forest covers

CHINESE JOURNAL OF ECO-AGRICULTURE ◽

10.3724/sp.j.1011.2009.00041 ◽

2009 ◽

Vol 17 (1) ◽

pp. 41-47 ◽

Cited By ~ 6

Author(s):

Jian ZHANG ◽

Si-Long WANG ◽

Qing-Kui WANG ◽

Yan-Xin LIU

Keyword(s):

Organic Carbon ◽

Seasonal Change ◽

Labile Organic Carbon ◽

Soil Labile Organic Carbon

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Impact of aquaculture on distribution of dissolved organic matter in coastal Jeju Island, Korea, based on absorption and fluorescence spectroscopy

Environmental Science and Pollution Research ◽

10.1007/s11356-021-15553-3 ◽

2021 ◽

Author(s):

Jeonghyun Kim ◽

Yeseul Kim ◽

Sung Eun Park ◽

Tae-Hoon Kim ◽

Bong-Guk Kim ◽

...

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Fluorescence Spectroscopy ◽

Dissolved Organic Matter ◽

Coastal Water ◽

Coastal Region ◽

Principal Component ◽

Distribution Patterns ◽

Organic Pollution ◽

Jeju Island

AbstractIn Jeju Island, multiple land-based aquafarms were fully operational along most coastal region. However, the effect of effluent on distribution and behaviours of dissolved organic matter (DOM) in the coastal water are still unknown. To decipher characteristics of organic pollution, we compared physicochemical parameters with spectral optical properties near the coastal aquafarms in Jeju Island. Absorption spectra were measured to calculate the absorption coefficient, spectral slope coefficient, and specific UV absorbance. Fluorescent DOM was analysed using fluorescence spectroscopy coupled with parallel factor analysis. Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were measured using high-temperature catalytic oxidation. The DOC concentration near the discharge outlet was twice higher than that in natural groundwater, and the TDN concentration exponentially increased close to the outlet. These distribution patterns indicate that aquafarms are a significant source of DOM. Herein, principal component analysis was applied to categorise the DOM origins. There were two distinct groups, namely, aquaculture activity for TDN with humic-like and high molecular weights DOM (PC1: 48.1%) and natural biological activity in the coastal water for DOC enrichment and protein-like DOM (PC2: 18.8%). We conclude that the aquafarms significantly discharge organic nitrogen pollutants and provoke in situ production of organic carbon. Furthermore, these findings indicate the potential of optical techniques for the efficient monitoring of anthropogenic organic pollutants from aquafarms worldwide.

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Traces of sunlight in the organic matter biogeochemistry of two shallow subarctic lakes

Biogeochemistry ◽

10.1007/s10533-021-00820-9 ◽

2021 ◽

Author(s):

Marttiina V. Rantala ◽

Carsten Meyer-Jacob ◽

E. Henriikka Kivilä ◽

Tomi P. Luoto ◽

Antti. E. K. Ojala ◽

...

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Lake Sediments ◽

Lake Water ◽

Human Impacts ◽

Global Environmental Change ◽

Carbon Export ◽

Subarctic Lakes ◽

Carbon Regulation ◽

In Situ Experiments

AbstractGlobal environmental change alters the production, terrestrial export, and photodegradation of organic carbon in northern lakes. Sedimentary biogeochemical records can provide a unique means to understand the nature of these changes over long time scales, where observational data fall short. We deployed in situ experiments on two shallow subarctic lakes with contrasting light regimes; a clear tundra lake and a dark woodland lake, to first investigate the photochemical transformation of carbon and nitrogen elemental (C/N ratio) and isotope (δ13C, δ15N) composition in lake water particulate organic matter (POM) for downcore inferences. We then explored elemental, isotopic, and spectral (inferred lake water total organic carbon [TOC] and sediment chlorophyll a [CHLa]) fingerprints in the lake sediments to trace changes in aquatic production, terrestrial inputs and photodegradation before and after profound human impacts on the global carbon cycle prompted by industrialization. POM pool in both lakes displayed tentative evidence of UV photoreactivity, reflected as increasing δ13C and decreasing C/N values. Through time, the tundra lake sediments traced subtle shifts in primary production, while the woodland lake carried signals of changing terrestrial contributions, indicating shifts in terrestrial carbon export but possibly also photodegradation rates. Under global human impact, both lakes irrespective of their distinct carbon regimes displayed evidence of increased productivity but no conspicuous signs of increased terrestrial influence. Overall, sediment biogeochemistry can integrate a wealth of information on carbon regulation in northern lakes, while our results also point to the importance of considering the entire spectrum of photobiogeochemical fingerprints in sedimentary studies.

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