Phosphorus dynamics associated with partitioning of organic carbon oxidation pathways in the surface sediments of the deep Ulleung Basin, East Sea

As sediments play an important role as either a sink or a source of phosphorus (P) for water column, it is important to elucidate the major P fractions and behaviors (i.e., mobilization and immobilization) in the sediments to better understand P cycles in local and global scale. We investigated major P speciation associated with the partitioning of organic carbon (Corg) oxidation in the sediments to elucidate the P dynamics at two contrasting sediments in the continental shelf (EB1) and rise (EC1) in the Ulleung Basin (UB), East Sea. Sulfate reduction (SR) pre-dominated Corg oxidation at shelf site (EB 1), comprising % of Corg oxidation, whereas Mn- and Fe-reduction combined accounted for >80% of Corg oxidation in Mn-oxide and Fe-oxide-rich basin site (EC 1). Under SR-dominated condition (EB 1), H2S oxidation coupled to reductive dissolution of FeOOH to form precipitation of FeS induced the accumulation of dissolved iron and phosphate in the pore water. On the other hand, phosphate in the Mn- and Fe-oxide-rich basin sediments (EC 1) was depleted because the P released through organic matter decomposition or reductive dissolution of Fe oxide/Mn oxide was effectively adsorbed to the metal-oxides in the surface sediments. Sequential extraction of P phases revealed that Fe bound P (52-65% of total P) was the major phase in the surface sediments of both sites. Interestingly, the organic P (Porg) fraction was 2.4-times higher at the basin site (12 &#956;mol g-1) than at the shelf site (5 &#956;mol g-1). Corg : Porg ratios presented as redox proxies in sediments were 644 and 191 for EB1 and EC1, respectively,. The results indicate that Porg has an effective preservation relative to Corg under sub-oxic conditions (EC1), whereas Porg was preferentially regenerated under anoxic conditions (EB1). Overall, the dynamics of P in the UB sediments were largely regulated by the partitioning of Corg oxidation pathways (i.e., sulfate reduction vs. metal reduction) and resultant interaction between Fe/Mn-S-P.

Download Full-text

Manganese and iron reduction dominate organic carbon oxidation in surface sediments of the deep Ulleung Basin, East Sea

Biogeosciences ◽

10.5194/bg-14-941-2017 ◽

2017 ◽

Vol 14 (4) ◽

pp. 941-958 ◽

Cited By ~ 18

Author(s):

Jung-Ho Hyun ◽

Sung-Han Kim ◽

Jin-Sook Mok ◽

Hyeyoun Cho ◽

Tongsup Lee ◽

...

Keyword(s):

Organic Carbon ◽

Iron Reduction ◽

Surface Sediments ◽

Ulleung Basin ◽

Oxide Content ◽

Nutrient Regeneration ◽

Relative Significance ◽

Oxidation Pathway ◽

Mn Oxide ◽

Geochemical Analyses

Abstract. Rates and pathways of benthic organic carbon (Corg) oxidation were investigated in surface sediments of the Ulleung Basin (UB) characterized by high Corg contents ( >  2.5 %, dry wt.) and very high contents of Mn oxides ( >  200 µmol cm−3) and Fe oxides (up to 100 µmol cm−3). The combination of geochemical analyses and independently executed metabolic rate measurements revealed that Mn and Fe reduction were the dominant Corg oxidation pathways in the center of the UB, comprising 45 and 20 % of total Corg oxidation, respectively. By contrast, sulfate reduction was the dominant Corg oxidation pathway, accounting for 50 % of total Corg mineralization in sediments of the continental slope. The relative significance of each Corg oxidation pathway matched the depth distribution of the respective electron acceptors. The relative importance of Mn reduction for Corg oxidation displays saturation kinetics with respect to Mn oxide content with a low half-saturation value of 8.6 µmol cm−3, which further implies that Mn reduction can be a dominant Corg oxidation process even in sediments with lower MnO2 content as known from several other locations. This is the first report of a high contribution of manganese reduction to Corg oxidation in offshore sediments on the Asian margin. The high manganese oxide content in the surface sediment in the central UB was maintained by an extreme degree of recycling, with each Mn atom on average being reoxidized ∼ 3800 times before permanent burial. This is the highest degree of recycling so far reported for Mn-rich sediments, and it appears linked to the high benthic mineralization rates resulting from the high Corg content that indicate the UB as a biogeochemical hotspot for turnover of organic matter and nutrient regeneration.

Download Full-text

Organic Carbon Cycling in Ulleung Basin Sediments, East Sea

Ocean and Polar Research ◽

10.4217/opr.2010.32.2.145 ◽

2010 ◽

Vol 32 (2) ◽

pp. 145-156 ◽

Cited By ~ 7

Author(s):

Tae-Hee Lee ◽

Dong-Seon Kim ◽

Boo-Keun Khim ◽

Dong-Lim Choi

Keyword(s):

Organic Carbon ◽

Carbon Cycling ◽

East Sea ◽

Ulleung Basin ◽

Organic Carbon Cycling

Download Full-text

Comparison of Sulfate Reduction Rates Associated with Geochemical Characteristics at the Continental Slope and Basin Sediments in the Ulleung Basin, East Sea

Ocean and Polar Research ◽

10.4217/opr.2010.32.3.299 ◽

2010 ◽

Vol 32 (3) ◽

pp. 299-307 ◽

Cited By ~ 3

Author(s):

Ok-Rye You ◽

Jin-Sook Mok ◽

Sung-Han Kim ◽

Dong-Lim Choi ◽

Jung-Ho Hyun

Keyword(s):

Sulfate Reduction ◽

Continental Slope ◽

Geochemical Characteristics ◽

East Sea ◽

Ulleung Basin ◽

Sulfate Reduction Rates

Download Full-text

Variations and Controls of Sulfate Reduction in the Continental Slope and Rise of the Ulleung Basin off the Southeast Korean Upwelling System in the East Sea

Geomicrobiology Journal ◽

10.1080/01490450903456731 ◽

2010 ◽

Vol 27 (2) ◽

pp. 212-222 ◽

Cited By ~ 18

Author(s):

Jung-Ho Hyun ◽

Jin-Sook Mok ◽

Ok-Rye You ◽

Dongseon Kim ◽

Dong-Lim Choi

Keyword(s):

Sulfate Reduction ◽

Continental Slope ◽

East Sea ◽

Ulleung Basin ◽

Upwelling System

Download Full-text

Chirp (2–7 kHz) echo characters and geotechnical properties of surface sediments in the Ulleung Basin, the East Sea

Geosciences Journal ◽

10.1007/bf02910492 ◽

1999 ◽

Vol 3 (4) ◽

pp. 213-224 ◽

Cited By ~ 8

Author(s):

Gil Young Kim ◽

Dae Choul Kim ◽

Soo Chul Park ◽

Gwang Hoon Lee

Keyword(s):

Surface Sediments ◽

Geotechnical Properties ◽

East Sea ◽

Ulleung Basin

Download Full-text

Organic carbon accumulation and sulfate reduction rates in slope and basin sediments of the Ulleung Basin, East/Japan Sea

Geo-Marine Letters ◽

10.1007/s00367-007-0097-8 ◽

2007 ◽

Vol 28 (3) ◽

pp. 153-159 ◽

Cited By ~ 32

Author(s):

Taehee Lee ◽

Jung-Ho Hyun ◽

Jin Sook Mok ◽

Dongseon Kim

Keyword(s):

Organic Carbon ◽

Sulfate Reduction ◽

Japan Sea ◽

Carbon Accumulation ◽

Ulleung Basin ◽

Sulfate Reduction Rates

Download Full-text

The Carbon-Sulfur Link in the Remineralization of Organic Carbon in Surface Sediments

Frontiers in Earth Science ◽

10.3389/feart.2021.652960 ◽

2021 ◽

Vol 9 ◽

Author(s):

Harold J. Bradbury ◽

Alexandra V. Turchyn ◽

Adam Bateson ◽

Gilad Antler ◽

Angus Fotherby ◽

...

Keyword(s):

Organic Carbon ◽

Isotopic Composition ◽

Sulfate Reduction ◽

Carbon Isotopic Composition ◽

Anaerobic Oxidation Of Methane ◽

Carbon Oxidation ◽

Pore Fluids ◽

Sulfur Isotopic Composition ◽

Carbon Isotopic ◽

Organic Carbon Oxidation

Here we present the carbon isotopic composition of dissolved inorganic carbon (DIC) and the sulfur isotopic composition of sulfate, along with changes in sulfate concentrations, of the pore fluid collected from a series of sediment cores located along a depth transect on the Iberian Margin. We use these data to explore the coupling of microbial sulfate reduction (MSR) to organic carbon oxidation in the uppermost (up to nine meters) sediment. We argue that the combined use of the carbon and sulfur isotopic composition, of DIC and sulfate respectively, in sedimentary pore fluids, viewed through a δ13CDIC vs. δ34SSO4 cross plot, reveals significant insight into the nature of carbon-sulfur coupling in marine sedimentary pore fluids on continental margins. Our data show systemic changes in the carbon and sulfur isotopic composition of DIC and sulfate (respectively) where, at all sites, the carbon isotopic composition of the DIC decreases before the sulfur isotopic composition of sulfate increases. We compare our results to global data and show that this behavior persists over a range of sediment types, locations and water depths. We use a reactive-transport model to show how changes in the amount of DIC in seawater, the carbon isotopic composition of organic matter, the amount of organic carbon oxidation by early diagenetic reactions, and the presence and source of methane influence the carbon and sulfur isotopic composition of sedimentary pore fluids and the shape of the δ13CDIC vs. δ34SSO4 cross plot. The δ13C of the DIC released during sulfate reduction and sulfate-driven anaerobic oxidation of methane is a major control on the minimum δ13CDIC value in the δ13CDIC vs. δ34SSO4 cross plot, with the δ13C of the organic carbon being important during both MSR and combined sulfate reduction, sulfate-driven AOM and methanogenesis.

Download Full-text