Relating Ocean Optics to Photochemical Transformations of Dissolved Organic Carbon in Coastal Waters

2001 ◽  
Author(s):  
William L. Miller
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Coastal Waters ◽  
Ocean Optics ◽  
Photochemical Transformations

scholarly journals Tracing terrestrial versus marine sources of dissolved organic carbon in a coastal bay using stable carbon isotopes

2020 ◽  
Vol 17 (1) ◽  
pp. 135-144 ◽  
Author(s):  
Shin-Ah Lee ◽  
Tae-Hoon Kim ◽  
Guebuem Kim
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Dissolved Organic Carbon ◽  
Coastal Waters ◽  
High Salinity ◽  
Carbon Isotopic Composition ◽  
C3 Plants ◽  
Stable Carbon ◽  
Coastal Bay

Abstract. The sources of dissolved organic matter (DOM) in coastal waters are diverse, and they play different roles in the biogeochemistry and ecosystems of the ocean. In this study, we measured dissolved organic carbon (DOC) and nitrogen (DON), the stable carbon isotopic composition of dissolved organic carbon (δ13C-DOC), and fluorescent dissolved organic matter (FDOM) in coastal bay waters surrounded by large cities (Masan Bay, Republic of Korea) to determine the different DOM sources in this region. The surface seawater samples were collected in two sampling campaigns (August 2011 and August 2016). The salinities were in the range of 10–21 in 2011 and 25–32 in 2016. In 2011, excess DOC was observed in high-salinity (16–21) waters; the excess DOC source was found to be mainly from marine autochthonous production according to the δ13C-DOC values (−23.7 ‰ to −20.6 ‰), the higher concentrations of protein-like FDOM, and the lower DOC∕DON (C∕N) ratios (8–15). In contrast, excess DOC observed in high-salinity waters in 2016 was characterized by low FDOM, more depleted δ13C values (−28.8 ‰ to −21.1 ‰), and high C∕N ratios (13–45), suggesting that the source of excess DOC is terrestrial C3 plants by direct land–seawater interactions. Our results show that multiple DOM tracers such as δ13C-DOC, FDOM, and C∕N ratios are powerful for determining different sources of DOM occurring in coastal waters.

Nutrient-Replete Benthic Microalgae as a Source of Dissolved Organic Carbon to Coastal Waters

2008 ◽  
Vol 31 (5) ◽  
pp. 860-876 ◽  
Author(s):  
William P. Porubsky ◽  
Liliana E. Velasquez ◽  
Samantha B. Joye
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Coastal Waters ◽  
Benthic Microalgae

Climatology and trends of Dissolved Organic Carbon in coastal waters off Sarawak, Borneo

2020 ◽  
Author(s):  
Nivedita Sanwlani ◽  
Patrick Martin ◽  
Nagur Cherukuru ◽  
Moritz Muller ◽  
Christopher Evans
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Coastal Waters ◽  
Distribution Patterns ◽  
Northeast Monsoon ◽  
Study Region ◽  
South West Monsoon ◽  
Ocean Carbon ◽  
Carbon Store

<p>South-East Asian peatlands are a globally significant carbon store. Rivers draining these peatlands have some of the highest dissolved organic carbon (DOC) concentrations in the world and account for up to 10% of the global land-to-ocean carbon flux, thus representing an important input to the marine carbon cycle. The release of DOC from peatlands is a natural process, yet the rapid and extensive transformation of these peatlands for agriculture over the past two decades is thought to have increased fluvial carbon losses significantly. However, not only do we lack a firm understanding of the fate of this terrigenous DOC in tropical seas, the distribution and long-term variability in DOC have never been studied at large scales in SE Asia. We will present the seasonal climatology (2002-2018) of spatial distribution patterns of DOC concentrations and optical properties (absorption coefficients, spectral slope) of colored dissolved organic matter (CDOM) for coastal waters of Sarawak, Malaysian Borneo derived using a regionally tailored semi-analytical inversion model from MODIS Aqua. Our results reveal substantial inputs of DOC from Sarawak rivers DOC close to shore exceeds 125 µM, and CDOM across the study region shows predominantly terrigenous spectral signatures. DOC concentrations were higher during the rainier northeast monsoon than during the drier south-west monsoon. Our data suggest that long-term increases in DOC concentration have occurred across parts of our study region from 2002–2018, which has implications for the aquatic light regime and coastal biogeochemistry[PM5]. These results will be discussed in the context of past anthropogenic disturbance to coastal peatlands.</p>

scholarly journals A Semi-Analytical Optical Remote Sensing Model to Estimate Suspended Sediment and Dissolved Organic Carbon in Tropical Coastal Waters Influenced by Peatland-Draining River Discharges off Sarawak, Borneo

2020 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Nagur Cherukuru ◽  
Patrick Martin ◽  
Nivedita Sanwlani ◽  
Aazani Mujahid ◽  
Moritz Müller
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Suspended Sediment ◽  
Coastal Water ◽  
Coastal Waters ◽  
Suspended Sediments ◽  
Optical Remote Sensing ◽  
Coastal Water Quality

Coastal water quality degradation is a global challenge. Marine pollution due to suspended sediments and dissolved matter impacts water colour, biogeochemistry, benthic habitats and eventually human populations that depend on marine resources. In Sarawak (Malaysian Borneo), peatland-draining river discharges containing suspended sediments and dissolved organic carbon influence coastal water quality at multiple locations along the coast. Optical remote sensing is an effective tool to monitor coastal waters over large areas and across remote geographic locations. However, the lack of regional optical measurements and inversion models limits the use of remote sensing observations for water quality monitoring in Sarawak. To overcome this limitation, we have (1) compiled a regional spectral optical library for Sarawak coastal waters, (2) developed a new semi-analytical remote sensing model to estimate suspended sediment and dissolved organic carbon in coastal waters, and (3) demonstrated the application of our remote sensing inversion model on satellite data over Sarawak. Bio-optical data analysis revealed that there is a clear spatial variability in the inherent optical properties of particulate and dissolved matter in Sarawak. Our optical inversion model coupled with the Sarawak spectral optical library performed well in retrieving suspended sediment (bias = 3% and MAE = 5%) and dissolved organic carbon (bias = 3% and MAE = 8%) concentrations. Demonstration products using MODIS Aqua data clearly showed the influence of large rivers such as the Rajang and Lupar in discharging suspended sediments and dissolved organic carbon into coastal waters. The bio-optical parameterisation, optical model, and remote sensing inversion approach detailed here can now help improve monitoring and management of coastal water quality in Sarawak.

Relationship between dissolved organic carbon and bacterial community in the coastal waters of Incheon, Korea

2017 ◽  
Vol 46 (1) ◽  
Author(s):  
Pengbin Wang ◽  
Jae-Hyoung Joo ◽  
Bum Soo Park ◽  
Joo-Hwan Kim ◽  
Jin Ho Kim ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Bacterial Community ◽  
Dissolved Organic Carbon ◽  
Coastal Waters ◽  
Abiotic Factors ◽  
Trophic Levels ◽  
Limiting Factor ◽  
Dissolved Inorganic Nutrients ◽  
Fluctuation Pattern ◽  
The Relationship

AbstractBacteria constitute a large domain of prokaryotic microorganisms present in marine ecosystems and play a significant role in energy flow and nutrient cycling. Bacterial community changes may affect organisms of higher trophic levels. We conducted field monitoring to study the relationship between dissolved organic carbon (DOC) and the bacterial community in the coastal waters of Incheon, Korea. Results showed that abiotic factors, such as temperature, salinity, dissolved oxygen (DO), pH, and dissolved inorganic nutrients, were not significantly different among the sampling sites during the study period. On the other hand, nutrient conditions were significantly different among the sites between 2012-2013 and 2014. Nitrogen was the limiting factor from 2012 to 2013, and phosphate in 2014. Biotic data showed that DOC affected both bacterial abundance and bacterial composition. A similar fluctuation pattern was observed for phytoplankton and Chlorophyll

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