Temporal variation in riverine organic carbon concentrations and fluxes in two contrasting estuary systems: Geum and Seomjin, South Korea

Kang, Sujin; Kim, Jung-Hyun; Kim, Daun; Song, Hyeongseok; Ryu, Jong-Sik; Ock, Giyoung; Shin, Kyung-Hoon

doi:10.1016/j.envint.2019.105126

Cited by 29 publications

(18 citation statements)

References 81 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Those facts give us some added confidence about the robustness of our conclusion. Our conclusion may also be supported by the results of Kang et al [36], who found that DOC fluxes were, in general, controlled by the water discharge in estuary systems. 5:00 9:00 13:00 17:00 .…”

Section: Resultssupporting

confidence: 90%

Dissolved and Particulate Organic Matter Dynamics Relative to Sediment Resuspension Induced by the Tidal Cycle in Macrotidal Estuaries, Kyushu, Japan

Takasu

Uchino

Mori

2020

Water

View full text Add to dashboard Cite

The tide-induced resuspension of sediments plays important roles in the efflux of particulate organic carbon (POC) from rivers to the coastal sea. Although dissolved organic carbon (DOC) comprises more than half of the riverine flux of organic carbon to the ocean, the influence of sediment resuspension induced by the tidal cycle on DOC dynamics is largely unknown. This study examined the dynamics of POC, particulate organic nitrogen (PON), DOC, humic-like and protein-like fluorescent dissolved organic matter (DOM) in relation to the tidal cycle in the Chikugo and Hayatsue River Estuaries, Kyushu, Japan. This study is the first to show both the particulate organic matter (POM) and DOM dynamics in relation to the tidal cycle in the macrotidal estuaries. We found that the turbidity changed with the tidal cycle and that there were significant positive correlations of turbidity with POC and PON in the Chikugo River mouth, suggesting that tide-induced sediment resuspension supplied POM to the water column. The DOC concentration, humic-like and protein-like fluorescent DOM were not correlated with turbidity but were negatively correlated with salinity. These results suggest that POM efflux, but not DOM efflux, can be accelerated by tide-induced sediment resuspension in the macrotidal estuaries.

show abstract

Section: Resultssupporting

confidence: 90%

Dissolved and Particulate Organic Matter Dynamics Relative to Sediment Resuspension Induced by the Tidal Cycle in Macrotidal Estuaries, Kyushu, Japan

Takasu

Uchino

Mori

2020

Water

View full text Add to dashboard Cite

show abstract

“…The observed δ 13 C values in riverine and estuarine-channel POM may be indicative of a considerable contribution of riverine algae to the estuarine POM pool. Previous studies, in the lowest reach of the Seomjin River, reported freshwater δ 13 C POM values (−26.5 ± 1.4 ) very close to our estuarine δ 13 C POM values and very low SPM concentrations (mean: 1.9-4.3 mg L −1 ) with restricted load delivery (28 ± 40 g C s −1 POC flux in the Seomjin River compared with 1122 ± 1007 g C s −1 in the adjacent Geum River with a diked estuary) (Yang and Choi, 2003;Kang et al, 2019). Based on the C:N (7.4-17.1) and POC:Chla (195 ± 156) ratios, and the positive correlations of both POM proxies with water discharge, those authors described an increased proportion of allochthonous (terrestrial) POC to the river-water POC pool and hydrological influence over POM concentrations in the Seomjin River.…”

Section: Dominance Of Phytoplankton-derived Pomsupporting

confidence: 79%

Dominance of Autochthonous Phytoplankton-Derived Particulate Organic Matter in a Low-Turbidity Temperate Estuarine Embayment, Gwangyang Bay, Korea

et al. 2020

View full text Add to dashboard Cite

In estuaries, the sources of organic matter, its composition, and its functional role in the coastal ecosystem food web are all influenced by dominant estuarine processes. We investigated seasonal variations in the quantity and composition of dissolved inorganic nutrients, suspended particulate matter (SPM), and phytoplankton across a low-turbidity estuarine-coastal continuum in Gwangyang Bay, South Korea. The narrow estuarine channel has a sharp salinity gradient (from 0 to around 30) and low SPM concentrations (<20 mg L −1). The channel carries river discharge, with a large quantity of nutrients (NO 3 and SiO 2), into the bay. The especially low SPM concentrations in the estuary (range: 2.0-29.1 mg L −1), and generous nutrient source, create an exceptionally low-turbidity condition in the water column and high primary productivity with no conspicuous spatial or seasonal trends. Gradually increasing δ 13 C values, low POC:Chla (<200), and low molar C:N (4-8) in the SPM, together with higher Chla concentrations at low SPM locations along the longitudinal transect, suggest that local production of phytoplankton has a strong influence on the distributional patterns of particulate organic matter. Short water-residence times, within the bay system, impede the accumulation of diverseorigin organic matter. The community composition of phytoplankton, distinguished by their size group, also plays a role in characterizing SPM quantity and composition. The results indicate that autochthonous pelagic production governs biogeochemical features in the low-turbidity estuarine embayment, contrasting with a prevalence of allochthonous organic matter, and its active processing, in highly turbid and/or longer residence-time systems.

show abstract

“…Previous studies have reported that particulate matter derived from erosion of soil may have low OC adsorption due to the low clay content of surface soils in the Jinsha River Basin (Wu et al, 2020), which agrees with the results of this study. Conversely, the POC/Chl-a threshold ratio of 300 indicates the dominance of phytoplankton in the POC pool (Suzuki et al, 2014;Kang et al, 2019;De Castro Bueno et al, 2020), and more than half of the samples in the surface water were classified with the origin of phytoplankton dominance (Figure S4), which is similar to the results of stable isotope mixing models.…”

Section: Particulate Organic Matter and Stable Isotopic Signaturessupporting

confidence: 71%

Methane accumulation affected by particulate organic carbon in upper Yangtze deep valley dammed cascade reservoirs, China

Zhang

et al. 2021

Preprint

View full text Add to dashboard Cite

Abstract. Methane (CH4) emissions from freshwaters to the atmosphere have a profound impact on global atmospheric greenhouse gas (GHG) concentrations. Anthropogenic footprints such as dam construction and reservoir operation significantly changed the fate and transport of CH4 in freshwaters. The type of particulate organic carbon (POC) in reservoirs is a critical factor controlling CH4 production and emissions. However, little is known of how reservoir operation mediates the distribution of POC and regulates CH4 accumulation in cascade hydroelectric reservoirs. Here, spatial and temporal variations in POC and CH4 were explored in the Xiluodu (XLD) and Xiangjiaba (XJB) reservoirs which are deep valley dammed cascade reservoirs located in the main channel of the upper Yangtze River. Based on the δ13C-POC and N / C mole ratios of particulate organic matter, the results of multi-endmember stable isotope mixing models by a Bayesian model show that terrestrial POC and autochthonous POC accounted for approximately 56 ± 19 % and 42 ± 19 % (SD, n = 181) of POC, respectively. CH4 concentrations and δ13C-CH4 in the cascade reservoirs were potentially influenced by CH4 oxidation. Together with other physicochemical parameters and structural equation model, these results suggested that the input of terrestrial POC was dominantly influenced by water level variations and flow regulation due to reservoir operation. The cumulative effect of POC caused by cascade reservoirs was not apparent at a bimonthly scale. Terrestrial POC was more likely to dominate CH4 accumulation in cascade reservoirs under reservoir operation.

show abstract

Temporal variation in riverine organic carbon concentrations and fluxes in two contrasting estuary systems: Geum and Seomjin, South Korea

Cited by 29 publications

References 81 publications

Dissolved and Particulate Organic Matter Dynamics Relative to Sediment Resuspension Induced by the Tidal Cycle in Macrotidal Estuaries, Kyushu, Japan

Dissolved and Particulate Organic Matter Dynamics Relative to Sediment Resuspension Induced by the Tidal Cycle in Macrotidal Estuaries, Kyushu, Japan

Dominance of Autochthonous Phytoplankton-Derived Particulate Organic Matter in a Low-Turbidity Temperate Estuarine Embayment, Gwangyang Bay, Korea

Methane accumulation affected by particulate organic carbon in upper Yangtze deep valley dammed cascade reservoirs, China

Contact Info

Product

Resources

About