Review of manuscript: „Distinctive effects of allochthonous and autochthonous organic matter on CDOM spectra in a tropical lake “ by Luciana Pena Mello Brandão, Ludmila Silva Brighenti, Peter Anton Staehr, Eero Asmala, Philippe Massicotte, Denise To

Abstract. Despite the increasing understanding about differences in carbon cycling between temperate and tropical freshwater systems, our knowledge on the importance of organic matter (OM) pools on light absorption properties in tropical lakes is very scarce. We performed a factorial mesocosm experiment in a tropical lake (Minas Gerais, Brazil) to evaluate the effects of increased concentrations of allochthonous and autochthonous OM on the light absorption characteristics of colored dissolved organic matter (CDOM), in addition to differences in light availability. We added inorganic nutrients (to stimulate OM autochthonous production by phytoplankton growth) and allochthonous OM, and also introduced shading. Dissolved organic carbon (DOC), Chl-a, nutrients, total suspended solid concentrations (TSM) and spectral CDOM absorption were measured every three days to evaluate how they responded to these treatments. CDOM quality was characterized by spectral indices (S250–450, S275–295, S350–450, SR and SUVA254). The effect of carbon sources on the spectral CDOM absorption was investigated through principal component (PCA) and redundancy (RDA) analyses. The two different OM sources affected CDOM quality differently. Spectral indices (S250–450 and SR) were mostly affected by allochthonous OM addition. The PCA showed that enrichment by allochthonous carbon had a strong effect on the CDOM spectra in the range between 300 and 400 nm, while the increase of autochthonous carbon increased absorption at wavelengths below 350 nm. Our results show that small inputs of allochthonous OM have much larger effects on the spectral characteristics on the lake CDOM, compared to large production of autochthonous OM.

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Distinctive effects of allochthonous and autochthonous organic matter on CDOM spectra in a tropical lake

Biogeosciences ◽

10.5194/bg-15-2931-2018 ◽

2018 ◽

Vol 15 (9) ◽

pp. 2931-2943 ◽

Cited By ~ 12

Author(s):

Luciana Pena Mello Brandão ◽

Ludmila Silva Brighenti ◽

Peter Anton Staehr ◽

Eero Asmala ◽

Philippe Massicotte ◽

...

Keyword(s):

Organic Matter ◽

Carbon Cycling ◽

Light Absorption ◽

Light Availability ◽

Principal Component ◽

Tropical Lake ◽

Tropical Lakes ◽

Spectral Indices ◽

Chl A ◽

Autochthonous Organic Matter

Abstract. Despite the increasing understanding about differences in carbon cycling between temperate and tropical freshwater systems, our knowledge on the importance of organic matter (OM) pools on light absorption properties in tropical lakes is very scarce. We performed a factorial mesocosm experiment in a tropical lake (Minas Gerais, Brazil) to evaluate the effects of increased concentrations of allochthonous and autochthonous OM, and differences in light availability on the light absorption characteristics of chromophoric dissolved organic matter (CDOM). Autochthonous OM deriving from phytoplankton ( ∼  Chl a) was stimulated by addition of nutrients, while OM from degradation of terrestrial leaves increased allochthonous OM, and neutral shading was used to manipulate light availability. Effects of the additions and shading on DOC, Chl a, nutrients, total suspended solid concentrations (TSM) and spectral CDOM absorption were monitored every 3 days. CDOM quality was characterized by spectral indices (S250–450, S275–295, S350–450, SR and SUVA254). Effects of carbon sources and shading on the spectral CDOM absorption was investigated through principal component (PCA) and redundancy (RDA) analyses. The two different OM sources affected CDOM quality very differently and shading had minor effects on OM levels, but significant effects on OM quality, especially in combination with nutrient additions. Spectral indices (S250–450 and SR) were mostly affected by allochthonous OM addition. The PCA showed that enrichment by allochthonous carbon had a strong effect on the CDOM spectra in the range between 300 and 400 nm, while the increase in autochthonous carbon increased absorption at wavelengths below 350 nm. Our study shows that small inputs of allochthonous OM can have large effects on the spectral light absorption compared to large production of autochthonous OM, with important implications for carbon cycling in tropical lakes.

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Organo-Mineral Interactions Are More Important for Organic Matter Retention in Subsoil Than Topsoil

Soil Systems ◽

10.3390/soilsystems4010004 ◽

2020 ◽

Vol 4 (1) ◽

pp. 4 ◽

Cited By ~ 2

Author(s):

Vincent Poirier ◽

Isabelle Basile-Doelsch ◽

Jérôme Balesdent ◽

Daniel Borschneck ◽

Joann K. Whalen ◽

...

Keyword(s):

Organic Matter ◽

Crop Residue ◽

Crop Residues ◽

Clay Content ◽

X Ray Diffraction ◽

Density Fractions ◽

Organic Matter Concentration ◽

Fractionation Procedure ◽

Autochthonous Organic Matter ◽

C And N

Decomposing crop residues contribute to soil organic matter (SOM) accrual; however, the factors driving the fate of carbon (C) and nitrogen (N) in soil fractions are still largely unknown, especially the influence of soil mineralogy and autochthonous organic matter concentration. The objectives of this work were (1) to evaluate the retention of C and N from crop residue in the form of occluded and mineral-associated SOM in topsoil (0–20 cm) and subsoil (30–70 cm) previously incubated for 51 days with 13C-15N-labelled corn residues, and (2) to explore if specific minerals preferentially control the retention of residue-derived C and N in topsoil and subsoil. We used topsoil and subsoil having similar texture and mineralogy as proxies for soils being rich (i.e., topsoil) and poor (i.e., subsoil) in autochthonous organic matter. We performed a sequential density fractionation procedure and measured residue-derived C and N in occluded and mineral-associated SOM fractions, and used X-ray diffraction analysis of soil density fractions to investigate their mineralogy. In accordance with our hypothesis, the retention of C and N from crop residue through organo-mineral interactions was greater in subsoil than topsoil. The same minerals were involved in the retention of residue-derived organic matter in topsoil and subsoil, but the residue-derived organic matter was associated with a denser fraction in the subsoil (i.e., 2.5–2.6 g cm−3) than in the topsoil (i.e., 2.3–2.5 g cm−3). In soils and soil horizons with high clay content and reactive minerals, we find that a low SOM concentration leads to the rapid stabilization of C and N from newly added crop residues.

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Distinguishing between terrestrial and autochthonous organic matter sources in marine environments using fluorescence spectroscopy

Marine Chemistry ◽

10.1016/j.marchem.2007.10.003 ◽

2008 ◽

Vol 108 (1-2) ◽

pp. 40-58 ◽

Cited By ~ 425

Author(s):

Kathleen R. Murphy ◽

Colin A. Stedmon ◽

T. David Waite ◽

Gregory M. Ruiz

Keyword(s):

Organic Matter ◽

Fluorescence Spectroscopy ◽

Marine Environments ◽

Organic Matter Sources ◽

Autochthonous Organic Matter

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Allochthonous and autochthonous organic matter in natural waters: Kinetic and thermodynamic patterns of transformation and quantitative and qualitative compositions

Doklady Earth Sciences ◽

10.1134/s1028334x17120273 ◽

2017 ◽

Vol 477 (2) ◽

pp. 1510-1514 ◽

Cited By ~ 1

Author(s):

P. A. Lozovik ◽

M. V. Zobkova ◽

A. V. Ryzhakov ◽

M. B. Zobkov ◽

T. A. Efremova ◽

...

Keyword(s):

Organic Matter ◽

Natural Waters ◽

Autochthonous Organic Matter

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An isotopic model for the origin of autochthonous organic matter contained in the bottom sediments of a reservoir

International Journal of Sediment Research ◽

10.1016/j.ijsrc.2017.10.002 ◽

2018 ◽

Vol 33 (3) ◽

pp. 285-293 ◽

Cited By ~ 6

Author(s):

Piotr Koszelnik ◽

Renata Gruca-Rokosz ◽

Lilianna Bartoszek

Keyword(s):

Organic Matter ◽

Bottom Sediments ◽

Autochthonous Organic Matter ◽

Isotopic Model

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Bacterial processes and biogeochemical changes in the water body of kettle holes - mainly driven by autochthonous organic matter?

Aquatic Sciences ◽

10.1007/s00027-017-0528-1 ◽

2017 ◽

Vol 79 (3) ◽

pp. 675-687 ◽

Cited By ~ 2

Author(s):

Katrin Attermeyer ◽

Hans-Peter Grossart ◽

Sabine Flury ◽

Katrin Premke

Keyword(s):

Organic Matter ◽

Water Body ◽

Autochthonous Organic Matter

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Оптические свойства растворенного органического вещества поверхностного слоя воды моря Лаптевых

Журнал технической физики ◽

10.21883/os.2019.03.47382.309-18 ◽

2019 ◽

Vol 126 (3) ◽

pp. 383

Author(s):

А.Н. Дроздова

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Continental Slope ◽

Riverine Water ◽

Lena River ◽

Humic Compounds ◽

Fluorescence Maximum ◽

Autochthonous Organic Matter ◽

Main Component ◽

Lena River Delta

AbstractFeatures of fluorescence of humic compounds transported by the Lena River runoff in September 2015 are considered. The change in optical properties of dissolved organic matter, namely, fluorescence spectra and absorption coefficients at a wavelength of 350 nm, on the transect from the Lena River delta to the continental slope is demonstrated. For humic compounds of terrigenous origin, the position of the fluorescence maximum has been determined at excitation wavelengths of 270, 310, and 355 nm. It has been shown that fresh riverine waters of Lena River propagate throughout the entire shelf and humic compounds are the main component of the colored fraction of dissolved organic matter. In samples collected near the continental slope, the presence of labile autochthonous organic matter has been revealed. The content of dissolved organic matter in riverine water in 2015 is comparable with results of previous investigations and amounts to 548 μM/L.

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