scholarly journals Behavior of Dissolved Organic Matter in Coral Reef Waters in Relation with Biological Processes

2011 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohamed Farook Mohamed Fairoz ◽  
Beatriz E. Casareto ◽  
Yoshimi Suzuki
Keyword(s):  
Organic Matter ◽  
Coral Reef ◽  
Dissolved Organic Matter ◽  
Biological Processes

scholarly journals Rhizobactin B is the preferred siderophore by a novel Pseudomonas isolate to obtain iron from dissolved organic matter in peatlands

BioMetals ◽  
2020 ◽  
Vol 33 (6) ◽  
pp. 415-433
Author(s):  
Stefan Kügler ◽  
Rebecca E. Cooper ◽  
Johanna Boessneck ◽  
Kirsten Küsel ◽  
Thomas Wichard
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Ligand Exchange ◽  
High Resolution Mass Spectrometry ◽  
Iron Acquisition ◽  
Water Extract ◽  
Resonance Spectroscopy ◽  
Biological Processes ◽  
Polycarboxylic Acid ◽  
Chelating Compounds

AbstractBacteria often release diverse iron-chelating compounds called siderophores to scavenge iron from the environment for many essential biological processes. In peatlands, where the biogeochemical cycle of iron and dissolved organic matter (DOM) are coupled, bacterial iron acquisition can be challenging even at high total iron concentrations. We found that the bacterium Pseudomonas sp. FEN, isolated from an Fe-rich peatland in the Northern Bavarian Fichtelgebirge (Germany), released an unprecedented siderophore for its genus. High-resolution mass spectrometry (HR-MS) using metal isotope-coded profiling (MICP), MS/MS experiments, and nuclear magnetic resonance spectroscopy (NMR) identified the amino polycarboxylic acid rhizobactin and a novel derivative at even higher amounts, which was named rhizobactin B. Interestingly, pyoverdine-like siderophores, typical for this genus, were not detected. With peat water extract (PWE), studies revealed that rhizobactin B could acquire Fe complexed by DOM, potentially through a TonB-dependent transporter, implying a higher Fe binding constant of rhizobactin B than DOM. The further uptake of Fe-rhizobactin B by Pseudomonas sp. FEN suggested its role as a siderophore. Rhizobactin B can complex several other metals, including Al, Cu, Mo, and Zn. The study demonstrates that the utilization of rhizobactin B can increase the Fe availability for Pseudomonas sp. FEN through ligand exchange with Fe-DOM, which has implications for the biogeochemical cycling of Fe in this peatland.

scholarly journals Dissolved organic matter concentration changes in river waters of Latvia

2011 ◽  
Vol 65 (1-2) ◽  
pp. 40-47
Author(s):  
Māris Kļaviņš ◽  
Ilga Kokorīte ◽  
Valērijs Rodinovs
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Water Bodies ◽  
Biological Processes ◽  
River Waters ◽  
Organic Matter Concentration ◽  
Concentration Changes ◽  
The Impact ◽  
Matter Concentration

Dissolved organic matter concentration changes in river waters of Latvia Amounts of natural organic matter in surface waters reflect the character and intensity of biological processes in water bodies, human impact and depend on the physico-geographical environment and land-use in the catchments. Thus, analysis of the concentrations and loadings of organic substances to adjacent water bodies can be used to indicate environmental change and human impacts. This study revealed significant increasing trends of total organic carbon (TOC) and water colour in most of the studied Latvian rivers during the last decade. However, over longer time periods, there have been pronounced oscillations of TOC concentrations, stressing the importance of long-term changes of river discharge. On a yearly basis, there was a positive correlation between parameters of organic matter concentration and discharge in all selected rivers. The impact of discharge on concentrations of organic matter can be masked by other factors, such as changes in precipitation, biological processes, soil types and land-use.

Observations on particulate and dissolved organic matter in coral reef areas

1975 ◽  
Vol 60 (3) ◽  
pp. 335-345 ◽  
Author(s):  
Nelson Marshall ◽  
Ann G. Durbin ◽  
Ray Gerber ◽  
Gregory Telek
Keyword(s):  
Organic Matter ◽  
Coral Reef ◽  
Dissolved Organic Matter

scholarly journals Remote Sensing of Coral Reefs: Uncertainty in the Detection of Benthic Cover, Depth, and Water Constituents Imposed by Sensor Noise

2018 ◽  
Vol 8 (12) ◽  
pp. 2691 ◽  
Author(s):  
Steven Ackleson ◽  
Wesley Moses ◽  
Marcos Montes
Keyword(s):  
Remote Sensing ◽  
Organic Matter ◽  
Coral Reef ◽  
Coral Reefs ◽  
Dissolved Organic Matter ◽  
Parameter Uncertainty ◽  
Sensor Noise ◽  
Water Constituents ◽  
Bottom Depth ◽  
The Impact

Coral reefs are biologically diverse and economically important ecosystems that are on the decline worldwide in response to direct human impacts and climate change. Ocean color remote sensing has proven to be an important tool in coral reef research and monitoring. Remote sensing data quality is driven by factors related to sensor design and environmental variability. This work explored the impact of sensor noise, defined as the signal to noise ratio (SNR), on the detection uncertainty of key coral reef ecological properties (bottom depth, benthic cover, and water quality) in the absence of environmental uncertainties. A radiative transfer model for a shallow reef environment was developed and Monte Carlo methods were employed to identify the range in environmental conditions that are spectrally indistinguishable from true conditions as a function of SNR. The spectrally averaged difference between remotely sensed radiance relative to sensor noise, ε, was used to quantify uncertainty in bottom depth, the fraction of benthic cover by coral, algae, and uncolonized sand, and the concentration of water constituents defined as chlorophyll, dissolved organic matter, and suspended calcite particles. Parameter uncertainty was found to increase with sensor noise (decreasing SNR) but the impact was non-linear. The rate of change in uncertainty per incremental change in SNR was greatest for SNR < 500 and increasing SNR further to 1000 resulted in only modest improvements. Parameter uncertainty was complicated by the bottom depth and benthic cover. Benthic cover uncertainty increased with bottom depth, but water constituent uncertainty changed inversely with bottom depth. Furthermore, water constituent uncertainty was impacted by the type of constituent material in relation to the type of benthic cover. Uncertainty associated with chlorophyll concentration and dissolved organic matter increased when the benthic cover was coral and/or benthic algae while uncertainty in the concentration of suspended calcite increased when the benthic cover was uncolonized sand. While the definition of an optimal SNR is subject to user needs, we propose that SNR of approximately 500 (relative to 5% Earth surface reflectance and a clear maritime atmosphere) is a reasonable engineering goal for a future satellite sensor to support research and management activities directed at coral reef ecology and, more generally, shallow aquatic ecosystems.

Production and bacterial decomposition of dissolved organic matter in a fringing coral reef

2011 ◽  
Vol 67 (4) ◽  
pp. 427-437 ◽  
Author(s):  
Yasuaki Tanaka ◽  
Hiroshi Ogawa ◽  
Toshihiro Miyajima
Keyword(s):  
Organic Matter ◽  
Coral Reef ◽  
Dissolved Organic Matter ◽  
Bacterial Decomposition
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