Characteristics of Hypoxic Water Mass Occurrence in the Northwestern Gamak Bay, Korea, 2017

Jeong, Huiho; Choi, Sang Duk; Cho, Hyeon-Seo

doi:10.7837/kosomes.2021.27.6.708

Cited by 4 publications

(20 citation statements)

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“…Organic matter produced through a series of blooms settles at the surface sediments [9,10], and oxygen consumption is required for bacterial activity to decompose the organic matter [8,[11][12][13]. Concomitantly, the strong stratification in the water column causes the bottom hypoxia by inhibiting the oxygen supply to the bottom water [14,15].…”

Section: Introductionmentioning

confidence: 99%

“…Concomitantly, the strong stratification in the water column causes the bottom hypoxia by inhibiting the oxygen supply to the bottom water [14,15]. Prolonged oxygen consumption gives rise to anoxic waters with less than 1.0 mg/L of dissolved oxygen [9,15]. The definition of hypoxia differs among studies, primarily due to different responses of ecosystem function [16].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, phosphorus is also released into the overlying seawater from the surface sediments, and eutrophication is exacerbated [11,29]. Thus, the hypoxic conditions encourage the re-occurrence of phytoplankton blooms, and the resulting organic matter further consumes dissolved oxygen accelerating coastal eutrophication [9].…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies have investigated eutrophication status and the formation of bottom hypoxia in Gamak Bay [10,12,36,37]. However, recent patterns of hypoxia or anoxia demonstrating the earlier formation and longer duration in the bay have not been considered [9,13].…”

Section: Introductionmentioning

confidence: 99%

“…The researchers have also emphasized that hypoxia and nutrient elution from sediments are the primary factors of eutrophication in this bay [9,10,12,13]. Nevertheless, C, N, and P mass balances under reducing environments in the bottom water-surface sediment interface were rarely determined for Gamak Bay.…”

Section: Introductionmentioning

confidence: 99%

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C, N, and P Mass Balances in the Bottom Seawater–Surface Sediment Interface in the Reducing Environment due to Anoxic Water of Gamak Bay, Korea

Jeong

Kang

Cho

2022

Water

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Current mass balances of C, N, and P were estimated using a model (Fluxin = Fluxout + ΔFlux) from Gamak Bay, Korea, in August 2017, where eutrophication and reducing conditions are prevalent. To examine the current fluxes of particulate organic carbon (POC), nitrogen (PON), and phosphorus (POP), sinking and re-floating sediment traps were deployed, a sediment oxygen demand (SOD) chamber experiment and ex-situ nutrient incubation experiment were conducted, and Fick’s first law of diffusion was applied. The principal component analysis and cluster analysis were performed to identify the three groups of water masses based on the characteristics of the bay, including the effects of the reducing environment due to the anoxic water mass using 14 bottom water quality parameters. In the reducing environment (sampling point GA4), the SOD20 flux was 3047.2 mg O2/m2/d. Additionally, the net sinking POC flux was 861.0 mg C/m2/d, while 131.8% of the net sinking POC flux (1134.5 mg C/m2/d) was removed toward the overlying water. This indicates that the organic matter that had been deposited was decomposed as a flux of 273.6 mg C/m2/d. The net sinking PON flux was 187.9 mg N/m2/d, whereas 15.8% of the net sinking PON flux was eluted, and 84.2% remained in the surface sediments. The dissolved inorganic nitrogen (DIN) elution flux from the surface sediments consisted of NH4+ elution (33.7 mg N/m2/d) and NOx− elution (−4.1 mg N/m2/d) fluxes. Despite the net sinking POP flux being 26.0 mg P/m2/d, the 47.7 mg P/m2/d of DIP elution flux (179.5% of the net sinking POP flux) was eluted to the overlying water. Similar to C mass balance, the additional elution flux occurred. Therefore, severe eutrophication (16.5 of the Okaichi eutrophication index) with the lowest N:P ratio (2.6) in GA4 was noted. This indicates that not only the freshly exported organic matter to the surface sediments but also the biochemical processes under anoxic conditions played an essential role as a remarkable nutrient source–particularly P–for eutrophication in Gamak Bay, Korea.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

C, N, and P Mass Balances in the Bottom Seawater–Surface Sediment Interface in the Reducing Environment due to Anoxic Water of Gamak Bay, Korea

Jeong

Kang

Cho

2022

Water

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Study on the Selection of Fishing Ground by Fishing Vessel Fishery in Gamak Bay, South Sea of Korea

KOO,

KIM,

KANG

et al. 2024

JFMSE

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Microplastic Distribution Characteristics Considering the Marine Environment Based on Surface Seawater Quality Parameters in Southern Sea of Korea, 2019

Kim,

Jeong,

Kim

et al. 2024

Sustainability

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The present study determined the microplastic distributions in the surface water of the Southern Sea of Korea (SS01–SS09) in September 2019, depending on three groups (Groups A, B, and C) categorized via the principal component analysis and cluster analysis using the water quality parameters (water temperature, salinity, pH, dissolved oxygen, suspended particulate matter, and chlorophyll-a). The microplastic samples in the surface water were collected using a 300 μm-mesh neuston net. The microplastic abundance ranged from 0.10 to 5.08 (average 0.71 ± 1.64) particles/m3 in the entire sampling area. Median values in Groups A (SS01, SS02, and SS07), B (SS05, SS08, and SS09), and C (SS03, SS04, and SS06) were 0.14 ± 0.02, 0.12 ± 0.14, and 0.17 ± 2.85 particles/m3, respectively, and there were no statistically significant differences (p < 0.050). However, it was highlighted that the most considerably numerous microplastic abundance in SS04 (5.08 particles/m3) revealed relatively high water temperatures distinguished from other sampling areas. Polystyrene, consisting mainly of expanded polystyrene, was the predominant polymer type, accounting for 81.5% in Groups A, 84.4% in B, and 97.0% in C. The particle size in Group C (average 3.11 ± 1.08 mm) was statistically larger (p < 0.001) than those of Groups A (average 0.71 ± 1.06 mm) and B (average 0.98 ± 1.22 mm). Only fragment and sheet shapes were found in all the sampling points and the former, which consisted of the secondary microplastics regardless of the groups, was the dominant type. The fragment composition gradually increased from 77.3% in Group A, 96.7% in B, to 99.1% in C. However, the strategy studies should be investigated in the foreseeable future to supplement the current study limitations, such as verifying the effect of the Yangtze River and the Tsushima warm current, and seasonal fluctuation.

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Characteristics of Hypoxic Water Mass Occurrence in the Northwestern Gamak Bay, Korea, 2017

Cited by 4 publications

References 0 publications

C, N, and P Mass Balances in the Bottom Seawater–Surface Sediment Interface in the Reducing Environment due to Anoxic Water of Gamak Bay, Korea

C, N, and P Mass Balances in the Bottom Seawater–Surface Sediment Interface in the Reducing Environment due to Anoxic Water of Gamak Bay, Korea

Study on the Selection of Fishing Ground by Fishing Vessel Fishery in Gamak Bay, South Sea of Korea

Microplastic Distribution Characteristics Considering the Marine Environment Based on Surface Seawater Quality Parameters in Southern Sea of Korea, 2019

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