scholarly journals Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems

10.3791/54704 ◽  
2016 ◽  
Author(s):  
Adam S. Wymore ◽  
Bianca Rodríguez-Cardona ◽  
William H. McDowell
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Stream Ecosystems

scholarly journals Functional and Structural Responses of Hyporheic Biofilms to Varying Sources of Dissolved Organic Matter

2014 ◽  
Vol 80 (19) ◽  
pp. 6004-6012 ◽  
Author(s):  
Karoline Wagner ◽  
Mia M. Bengtsson ◽  
Katharina Besemer ◽  
Anna Sieczko ◽  
Nancy R. Burns ◽  
...  
Keyword(s):  
Organic Matter ◽  
16S Rrna ◽  
Dissolved Organic Matter ◽  
Community Composition ◽  
Hyporheic Zone ◽  
Priority Effects ◽  
Stream Ecosystems ◽  
Rrna Gene ◽  
Structural Responses

ABSTRACTHeadwater streams are tightly connected with the terrestrial milieu from which they receive deliveries of organic matter, often through the hyporheic zone, the transition between groundwater and streamwater. Dissolved organic matter (DOM) from terrestrial sources (that is, allochthonous) enters the hyporheic zone, where it may mix with DOM fromin situproduction (that is, autochthonous) and where most of the microbial activity takes place. Allochthonous DOM is typically considered resistant to microbial metabolism compared to autochthonous DOM. The composition and functioning of microbial biofilm communities in the hyporheic zone may therefore be controlled by the relative availability of allochthonous and autochthonous DOM, which can have implications for organic matter processing in stream ecosystems. Experimenting with hyporheic biofilms exposed to model allochthonous and autochthonous DOM and using 454 pyrosequencing of the 16S rRNA (targeting the “active” community composition) and of the 16S rRNA gene (targeting the “bulk” community composition), we found that allochthonous DOM may drive shifts in community composition whereas autochthonous DOM seems to affect community composition only transiently. Our results suggest that priority effects based on resource-driven stochasticity shape the community composition in the hyporheic zone. Furthermore, measurements of extracellular enzymatic activities suggest that the additions of allochthonous and autochthonous DOM had no clear effect on the function of the hyporheic biofilms, indicative of functional redundancy. Our findings unravel possible microbial mechanisms that underlie the buffering capacity of the hyporheic zone and that may confer stability to stream ecosystems.

Dissolved Organic Matter in Stream Ecosystems

2016 ◽  
pp. 241-320 ◽  
Author(s):  
L.A. Kaplan ◽  
R.M. Cory
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Stream Ecosystems

scholarly journals Use of optical absorption indices to assess seasonal variability of dissolved organic matter in Amazon floodplain lakes

2020 ◽  
Vol 17 (21) ◽  
pp. 5355-5364
Author(s):  
Maria Paula da Silva ◽  
Lino A. Sander de Carvalho ◽  
Evlyn Novo ◽  
Daniel S. F. Jorge ◽  
Claudio C. F. Barbosa
Keyword(s):  
Remote Sensing ◽  
Organic Matter ◽  
Optical Absorption ◽  
Dissolved Organic Matter ◽  
Seasonal Variability ◽  
Large Scale ◽  
Remote Sensing Data ◽  
Floodplain Lakes ◽  
Sentinel 2

Abstract. Given the importance of dissolved organic matter (DOM) in the carbon cycling of aquatic ecosystems, information on its seasonal variability is crucial. In this study we assess the use of optical absorption indices available in the literature based on in situ data to both characterize the seasonal variability of DOM in a highly complex environment and for application in large-scale studies using remote sensing data. The study area comprises four lakes located in the Mamirauá Sustainable Development Reserve (MSDR). Samples for the determination of colored dissolved organic matter (CDOM) and measurements of remote sensing reflectance (Rrs) were acquired in situ. The Rrs was used to simulate the response of the visible bands of the Sentinel-2 MultiSpectral Instrument (MSI), which was used in the proposed models. Differences between lakes were tested using the CDOM indices. The results highlight the role of the flood pulse in the DOM dynamics at the floodplain lakes. The validation results show that the use of the absorption coefficient of CDOM (aCDOM) as a proxy of the spectral slope between 275 and 295 nm (S275–295) during rising water is worthwhile, demonstrating its potential application to Sentinel-2 MSI imagery data for studying DOM dynamics on the large scale.

scholarly journals Use of absorption optical indices to assess seasonal variability of dissolved organic matter in amazon floodplain lakes

2019 ◽  
Author(s):  
Maria Paula da Silva ◽  
Lino A. Sander de Carvalho ◽  
Evlyn Novo ◽  
Daniel S. F. Jorge ◽  
Claudio C. F. Barbosa
Keyword(s):  
Remote Sensing ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Seasonal Variability ◽  
Large Scale ◽  
River Bank ◽  
In Situ Data ◽  
Amazon Floodplain ◽  
Significant Difference

Abstract. Given the importance of DOM in the carbon cycling of aquatic ecosystems, information on its seasonal variability is crucial. This study assesses the use of available absorption optical indices based on in situ data to both characterize the seasonal variability of the DOM dynamics in a highly complex environment and their viability of being used for satellite remote sensing on large scale studies. The study area comprises four lakes located at the Mamirauá Sustainable Development Reserve (MSDR). Samples for the determination of coloured dissolved organic matter (CDOM) and remote sensing reflectance (Rrs) were acquired in situ. The Rrs was applied to simulate MSI visible bands and used in the proposed models. Differences between lakes were tested regarding CDOM indices. Significant difference in the average of aCDOM (440), aCDOM spectra and S275–295 were found between lakes located inside the flood forest and those near the river bank. The proposed model showed that aCDOM can be used as proxy of S275–295 during rising water with good validation results, demonstrating the potential of Sentinel/MSI imagery data in large scale studies on the dynamics of DOM.

scholarly journals Sedimentary supply of humic-like fluorescent dissolved organic matter and its implication for chemoautotrophic microbial activity in the Izu-Ogasawara Trench

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Shigemitsu ◽  
T. Yokokawa ◽  
H. Uchida ◽  
S. Kawagucci ◽  
A. Murata
Keyword(s):  
Organic Matter ◽  
Community Structure ◽  
Dissolved Organic Matter ◽  
Oxygen Utilization ◽  
Fluorescent Dissolved Organic Matter ◽  
Vertical Distributions ◽  
The Difference ◽  
The Relationship ◽  
Apparent Oxygen Utilization

AbstractMicrobial community structure in the hadal water is reported to be different from that in the upper abyssal water. However, the mechanism governing the difference has not been fully understood. In this study, we investigate the vertical distributions of humic-like fluorescent dissolved organic matter (FDOMH), chemoautotrophic production, apparent oxygen utilization (AOU), and N* in the Izu-Ogasawara Trench. In the upper abyssal waters (< 6000 m), FDOMH has a significantly positive correlation with AOU; FDOMH deviates from the relationship and increases with depth without involving the increment of AOU in the hadal waters. This suggests that FDOMH is transferred from the sediments to the hadal waters through pore water, while the FDOMH is produced in situ in the upper abyssal waters. Chemoautotrophic production and N* increases and decreases with depth in the hadal waters, respectively. This corroborates the effluxes of dissolved substances, including dissolved organic matter and electron donors from sediments, which fuels the heterotrophic/chemoautotrophic microbial communities in the hadal waters. A simple box model analysis reveals that the funnel-like trench topography facilitates the increase in dissolved substances with depth in the hadal waters, which might contribute to the unique microbiological community structure in these waters.

IN-SITU OPTICAL SENSORS REVEAL HOT MOMENTS OF DISSOLVED ORGANIC MATTER EXPORT IN SLEEPERS RIVER RESEARCH WATERSHED, VERMONT

2018 ◽  
Author(s):  
Kevin Ryan ◽  
◽  
James B. Shanley ◽  
Aron Stubbins ◽  
Julia Perdrial ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Optical Sensors

Composition of the dissolved organic matter produced during in situ burning of spilled oil

2019 ◽  
Vol 138 ◽  
pp. 103926 ◽  
Author(s):  
Aprami Jaggi ◽  
Jagoš R. Radović ◽  
Lloyd R. Snowdon ◽  
Stephen R. Larter ◽  
Thomas B.P. Oldenburg
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Spilled Oil

Using diffusive gradients in thin films to probe the kinetics of metal interaction with algal exudates

2011 ◽  
Vol 8 (5) ◽  
pp. 517 ◽  
Author(s):  
Jacqueline Levy ◽  
Hao Zhang ◽  
William Davison ◽  
Rene Groben
Keyword(s):  
Thin Films ◽  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Chlorella Vulgaris ◽  
Metal Speciation ◽  
The Relationship ◽  
Diffusive Gradients ◽  
Kinetics Of

Environmental context Interaction of metals with dissolved organic matter is one of the key processes defining metal bioavailability in water. The technique of diffusive gradients in thin films was used to investigate the kinetics of the interaction between metals and dissolved organic matter released by algae. For most metals the rate at which they were released from the organic matter was fast, but release of iron was kinetically limited. AbstractThe interaction of metals with organic matter is one of the key processes determining metal speciation and bioavailability in water. Fulvic acid tends to dominate dissolved organic carbon (DOC) in freshwaters, but organic carbon produced in situ, e.g. exudates released by algae and bacteria, is also significant. The technique of diffusive gradients in thin films (DGT) was used to investigate the lability of metal–exudate complexes using a kinetic signature approach. Exudates were harvested from three cultured freshwater alga (Chlorella vulgaris, Cryptomonas pyrenoidifera, Anabaena flos-aquae) and the filtered media supplemented with trace metals. DGT-labile metal concentrations and kinetic signatures were determined (24-h deployment). The relationship between Fe and DOC was a defining feature of the kinetic signatures. Iron was the most kinetically limited metal followed by Al and Cu, whereas Co, Ni and Pb were effectively completely labile. Exudates from Chlorella vulgaris produced the most DOC and the most marked kinetic limitation.

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