scholarly journals Estimation of Source Origins of Organic Matter Inducing Oxygen-Depleted Water in Coastal Seas Using Stable Isotope Ratios of Carbon

2018 ◽  
Vol 41 (1) ◽  
pp. 1-10
Author(s):  
Shiho KOBAYASHI ◽  
Tateki FUJIWARA ◽  
Yukio KOMAI ◽  
Shuhei TANAKA ◽  
Yuji SUZUKI
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Isotope Ratios ◽  
Stable Isotope Ratios

Determination of the Origin of Particulate Organic Matter at the Estuary of Youngsan River using Stable Isotope Ratios (δ13C, δ15N).

2013 ◽  
Vol 46 (2) ◽  
pp. 175-184 ◽  
Author(s):  
Yeon-Jung Lee ◽  
◽  
Byung-Kwan Jeong ◽  
Yong-Sik Shin ◽  
Sung-Hwan Kim ◽  
...  
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Particulate Organic Matter ◽  
Isotope Ratios ◽  
Stable Isotope Ratios

Novel insights into the origin of dissolved organic carbon in the Sunda Shelf Sea using stable isotope ratios of hydrogen (d2H) and carbon (d13C). 

2021 ◽  
Author(s):  
Nikita Kaushal ◽  
Cristian Gudasz ◽  
Yongli Zhou ◽  
Adriana Lopes dos Santos ◽  
Avneet Kaur ◽  
...  
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Isotope Ratios ◽  
Southwest Monsoon ◽  
Coastal Ocean ◽  
Stable Isotope Ratios ◽  
Sunda Shelf ◽  
Shelf Sea

<p>Rivers deliver ~0.25 Pg C year<sup>-1</sup> of terrigenous dissolved organic carbon (tDOC) from land to shelf seas. As tDOC moves along the river, coastal ocean and deep ocean continuum, it undergoes complex biogeochemical processing that results in both chemical alteration and remineralisation. Remineralisation of tDOC to CO<sub>2 </sub>can contribute significantly to coastal ocean acidification and CO<sub>2</sub> emissions to the atmosphere. Our understanding of tDOC processing in coastal seas is still limited, in part because it is challenging to distinguish between marine and terrigenous DOC. The stable carbon isotope ratios (d<sup>13</sup>C) of the dissolved inorganic and organic carbon pools are commonly used to quantify tDOC, because terrestrial vegetation is typically more isotopically depleted (-32 to -25 ‰) compared to marine organic carbon (-24 to -20 ‰). However, this relatively small difference between the marine and terrigenous end-members can introduce large uncertainties in d<sup>13</sup>C-based estimates, particularly if tDOC originates from both C3 and C4 vegetation. End-member isotope ratio values with larger separation could potentially help to better quantify tDOC. Recent studies in freshwater ecosystems have shown that the stable isotope ratios (d<sup>2</sup>H) of the carbon bound non-exchangeable hydrogen fraction of dissolved organic matter (DOM) typically differs by more than 50 ‰ between terrestrially derived and aquatically derived dissolved organic matter. However, d<sup>2</sup>H has not yet been used as a tracer for tDOC in marine environments.</p><p>Here, we present results from a one year-long monthly time series of δ<sup>13</sup>C and δ<sup>2</sup>H at a coastal location in Southeast Asia’s Sunda Shelf Sea, where the southwest monsoon delivers a seasonal input of tDOC from tropical peatlands on Sumatra. We found that δ<sup>2</sup>H of solid-phase extracted DOM, as measured after dual water steam equilibration, ranged between -130 to ­­-150 ‰ during the southwest monsoon, but between -160 to -167 ‰ during other months. Fresh tDOC from peatland-draining rivers had values close to -100‰, and decreased somewhat upon partial photodegradation, while DOM produced in plankton enrichment cultures had values around -174‰. Values of d<sup>13</sup>C of DOC ranged from -25.5 to -23.0 ‰ during the southwest monsoon, and between -23.0 to -21.0 ‰ at other times. We will present preliminary mass balance calculations to estimate tDOC concentrations based on δ<sup>13</sup>C and δ<sup>2</sup>H. Our results suggest that δ<sup>2</sup>H can be a sensitive tracer of tDOC in the marine environment.</p>

Sign in / Sign up

Export Citation Format

Share Document