Origin, Variability, and Pathways of East Sea Intermediate Water in a High‐Resolution Ocean Reanalysis

Kim, Sangjin; Park, Young-Gyu; Kim, Young Ho; Seo, Seongbong; Jin, Hyunkeun; Pak, Gyundo; Lee, Ho Jin

doi:10.1029/2020jc017158

Cited by 14 publications

(12 citation statements)

References 45 publications

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“…The phytoplankton community of the EJS is characterized by the abundance and diversity of diatoms, dinoflagellates, and cyanobacteria (Choi et al, 2016). Diatoms are abundant in most of the regions, whereas the cyanobacteria abundance is comparatively high in the open waters (Kim S. Y. et al, 2021). Cyanobacteria occurs mainly in the surface mixed layer, whereas diatoms are dominant in the stratified zone at depths below 20 m (Kwak et al, 2017).…”

Section: Plankton Communitymentioning

confidence: 99%

“…Climate change affects hydrographic properties, water circulation, and, consequently, the biological and biogeochemical properties of the EJS (Chiba et al, 2008;Kim S. Y. et al, 2021). Joo et al (2016) Mass accumulation rate (colored circles; mg cm −2 yr −1 ) and SOC accumulation rate (values in brackets; molC cm −2 yr −1 ) in the EJS.…”

Section: Temporal Trendsmentioning

confidence: 99%

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Carbon cycling in the East Sea (Japan Sea): A review

Kim

Hwang²,

Kim³

et al. 2022

Front. Mar. Sci.

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The East Sea (also known as the Japan Sea; hereafter, EJS) is a semi-enclosed marginal sea surrounded by the Korean Peninsula, Russia, and the Japanese Islands. The EJS is connected to the Pacific through shallow straits. Thus, the EJS has its own thermohaline circulation and the characteristic biogeochemistry. The deep overturning circulation plays a critical role in carbon cycling including absorption of atmospheric CO2 and its sequestration into the interior of the sea. The turnover time of the deep EJS (>1000 m) is ~ hundred years and probably varies depending on physical climate forcing. Thus, the effect of climate change on oceanic processes may be more easily detected in the EJS. In this paper, we summarize the current understanding of carbon cycling in the EJS. We focus especially on the Ulleung Basin in the southwestern EJS, from which more extensive data are available. Notable features of carbon cycling in the EJS include the following: primary productivity and the export/production ratio are higher than in the adjacent Pacific; the EJS is a net sink of atmospheric CO2 and anthropogenic CO2 content is ~1% of the dissolved inorganic carbon inventory; dissolved inorganic carbon in the sea interior is mostly supplied by organic matter decomposition rather than CaCO3 dissolution and thus, the deep waters are vulnerable to acidification; N:P molar ratio of the deep waters is ~13, lower than the Redfield ratio; concentration of dissolved organic carbon is significantly higher than in the oceans; and sediment resuspension and lateral transport is an important component of sinking particulate organic carbon (POC) flux. Another important feature is the temporal trends observed for the last few decades. For example, pH, calcium carbonate saturation status, and dissolved oxygen concentration in the sea interior have decreased, whereas dissolved inorganic carbon and likely, the inventory of anthropogenic CO2 have increased. These temporal trends have an implication on better understanding of the processes occurring more slowly in the oceans. Brief suggestions for future research that will improve our understanding of carbon cycling and its variability are provided at the end of the paper.

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Section: Plankton Communitymentioning

confidence: 99%

Section: Temporal Trendsmentioning

confidence: 99%

Carbon cycling in the East Sea (Japan Sea): A review

Kim

Hwang²,

Kim³

et al. 2022

Front. Mar. Sci.

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“…Ocean analysis data of water temperature (SST), salinity (SSS), and sea surface currents for June and July 2019 were provided by the Korea Institute of Ocean Science and Technology (KIOST) [9]. Since March 2017, KIOST has been operating the "Ocean Predictability Experiment for Marine environment (OPEM)", a real-time ocean circulation prediction system in order to detect oceanographic phenomena such as cold water zones and high temperatures occurring in the waters surrounding the Korean Peninsula.…”

Section: Remote Sensing Analysesmentioning

confidence: 99%

“…Data assimilation on the vertical structure of water temperature and salinity was performed once every 7 days with input data from Argo (https://data-argo.ifremer.fr/latest_data/, accessed on 5 June 2019) and in-situ data for temperature and salinity profiles provided by Global Temperature and Salinity Profile Programme (https://www.ncei.noaa.gov/data/oceans/gtspp/realtime/meds_ascii/, accessed on 5 June 2019). A previous study [9] presented the main information of the OPEM system and verification results such as water temperature and salinity in the waters surrounding the Korean Peninsula. Satellite-based Chl a observation data used daily Himawari-8 Level 3, and a geostationary orbit satellite operated by the Japanese Meteorological Agency, and the spatial resolution of the data is 1/20 • [14].…”

Section: Remote Sensing Analysesmentioning

confidence: 99%

Summer Distributional Characteristics of Surface Phytoplankton Related with Multiple Environmental Variables in the Korean Coastal Waters

Yoon

Lee

Jin

et al. 2022

JMSE

Self Cite

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Multiple environmental variables related to ocean currents, freshwater runoff, and upwelling in a coastal area have complex effects on the phytoplankton community. To assess the influence of environmental variables on the phytoplankton community structure during the summer of 2019, we investigated the various abiotic and biotic factors in Korean coastal waters (KCWs), separated into five different zones. Summer environmental factors in KCWs were strongly influenced by Changjiang Diluted Water (CDW) in St. SO (Southern Offshore) 1 and 2, upwelling in St. SI (Southern Inshore) 2–4, and Nakdong River discharge in St. SI 12. In particular, low–salinity water masses (p < 0.05 for nearby locations) of CDW gradually expanded from the East China Sea to southwestern KCWs from June to July. In addition, there were high levels of nutrients following freshwater runoff from the Nakdong River in southeastern KCW, which led to the dominance of Cryptomonas spp. (81%), a freshwater and brackish water algae. On the other hand, upwelling areas in southwestern KCW were dominated by diatoms Skeletonema spp., and are characterized by high phosphate concentrations (p < 0.05) and low temperatures (p < 0.05) compared to nearby locations. Leptocylindrus danicus (20%) was dominant due to the effect of water temperature in the SE (Southeastern area) zone. Low nutrient concentrations were maintained in the East Sea (dissolved inorganic nitrogen (DIN) = 0.39 ± 0.40 μM; dissolved inorganic phosphate (DIP) = 0.09 ± 0.03 μM) and the Yellow Sea (DIN = 0.40 ± 0.07 μM; DIP = 0.04 ± 0.02 μM), which were characterized by low levels of chlorophyll a and dominated by unidentified small flagellates (35, 40%). Therefore, our results indicated that hydro–oceanographic events such as upwelling and freshwater run–off, but not ocean currents, provide nutrients to the euphotic layers of the coastal environment and play important roles in determining the phytoplankton community structure during summer in the KCWs.

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“…Modeling studies also estimated the ventilation time of the ESIW to be 6-10 years from the point of view of particle dispersion (Seung and Kim, 1997;Yoshikawa et al, 1999), and this may be related to the problem in which the low-resolution numerical models of the past underestimated the mean and eddy circulation at mid and deep layers (Park and Kim, 2013). The latest model results suggested that the ESIW arrived at the Ulleung Basin in a relatively short time of 1-2 years (Kim et al, 2021), which is comparable to the results of this study, although there is still a significant difference from the observed results in terms of the ESIW formation area. Because the ESIW ventilation timescale is important information, a study reconciling the chemical tracer-based, numerical model-based, and physical observation-based timescales is required.…”

Section: Remaining Studies and Implicationsmentioning

confidence: 99%

Long-Term Variability of the East Sea Intermediate Water Thickness: Regime Shift of Intermediate Layer in the Mid-1990s

Park

2022

Front. Mar. Sci.

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The shipboard measurements over approximately 55 years in the southwestern part of the East Sea (Sea of Japan) demonstrate a remarkable basin-wide, interannual-interdecadal variability in the temperature-based thickness of the East Sea Intermediate Water (ESIW) whose temporal variability shows strong correlation with the density-based thickness (r = 0.97). Relevant to the long-term variability of the ESIW thickness, clear changes in horizonal and vertical features have been observed at the intermediate layer in the mid-1990s, such as 1) increases in vertical temperature gradient in the thermocline by shoaling of 2°C–5°C isotherms, 2) relatively high correlations among isotherms in the interdecadal timescale, 3) appearance of zonal phase difference in the ESIW thickness variability after the mid-1990s, and 4) correlation phase change between the Arctic Oscillation Index and the ESIW thickness. The ESIW thickness could be smaller when its formation is weaker and when the formation of deep-water mass below it becomes stronger. Based on the features observed, we hypothesized on the regime shift concerning the East Sea meridional overturning circulation; before the mid-1990s, active deep-water formation mainly controlled the ESIW layer variability, but after the mid-1990s, the ESIW formation rate predominantly affected its own thickness variability.

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Origin, Variability, and Pathways of East Sea Intermediate Water in a High‐Resolution Ocean Reanalysis

Cited by 14 publications

References 45 publications

Carbon cycling in the East Sea (Japan Sea): A review

Carbon cycling in the East Sea (Japan Sea): A review

Summer Distributional Characteristics of Surface Phytoplankton Related with Multiple Environmental Variables in the Korean Coastal Waters

Long-Term Variability of the East Sea Intermediate Water Thickness: Regime Shift of Intermediate Layer in the Mid-1990s

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