Paleoceanographic Changes in the Japan Sea

The Japan Sea, a semi-enclosed marginal basin between the Eurasian continent and the Japanese archipelago, has experienced pronounced paleoceanographic shifts in response to glacial–interglacial cycles, tectonic events and monsoon variability over the Quaternary. During glacial low-stands, reduced sea levels and uplift of the adjacent shelves restricted exchange through the Tsushima and northern straits, promoting low-salinity stratification, oxygen depletion and the accumulation of distinct dark–light laminated hemipelagic sediments. In contrast, interglacial high-stands reconnected the basin to the open Pacific, enabling renewed inflow of the warm Tsushima Warm Current, enhanced ventilation and biogenic carbonate deposition. These alternating regimes have been recorded in the size and concentration of terrestrial phytoclasts, stable isotope ratios of benthic foraminifera, and the distribution of microfossil assemblages. Stratigraphic frameworks built on tephrostratigraphy and correlation of sediment colour layers permit orbital-scale age models, while high-resolution physical property records reveal millennial-scale monsoon influences on nutrient flux and organic carbon export. Local tectonic evolution, notably the near-closure of the northern strait in the Late Pliocene, combined with eustatic sea-level changes, underpinned shifts from Pacific-dominated deep-water conditions to episodes of restricted ventilation and anoxic events. Together, these findings demonstrate the Japan Sea’s role as a sensitive recorder of regional climatic and oceanographic forcing, offering critical analogues for understanding marginal basin responses to future global change.

Research from Nature Portfolio

Recent studies have applied palynofacies analysis to cores recovered from the Eastern South Korea Plateau, revealing that the size and concentration of phytoclasts transported into the basin oscillate in anti-phase with global sea-level curves. Over the past 750 ka, high amplitudes during glacial maxima reflect shortened transport pathways as continental shelves became exposed, while interglacial minima correspond to deeper straits and enhanced dilution. These insights underscore the combined influence of glacial–interglacial sea-level change and geotectonic stability on terrestrial sediment delivery to the Japan Sea.

Paleoceanographic Changes in the Japan Sea publication trend

The graph below shows the total number of articles in paleoceanographic changes in the japan sea across all publications each year (not limited to Nature Index journals).

Technical terms

Palynofacies: Distribution of organic particles in sediment, used to infer terrestrial input and transport mechanisms.

Tephrostratigraphy: Correlation of volcanic ash layers by composition and morphology to establish age frameworks.

Hemipelagic sediments: Fine-grained deposits derived from both pelagic and terrigenous sources, characteristic of semi-enclosed basins.

Benthic foraminiferal δ18O: Oxygen isotope ratio in bottom-dwelling foraminifera reflecting combined temperature and salinity changes.

Glacial–interglacial cycles: Repeated global climate fluctuations driven by orbital forcing, affecting sea level and ocean circulation.

References

1. New findings on palynofacies characteristics of semi-enclosed deep-sea environments in the East Sea over 2 million years. Scientific Reports (2020).
2. Integrated tephrostratigraphy and stable isotope stratigraphy in the Japan Sea and East China Sea using IODP Sites U1426, U1427, and U1429, Expedition 346 Asian Monsoon. Progress in Earth and Planetary Science (2018).
3. Transitional changes in microfossil assemblages in the Japan Sea from the Late Pliocene to Early Pleistocene related to global climatic and local tectonic events. Progress in Earth and Planetary Science (2016).
4. High-resolution and high-precision correlation of dark and light layers in the Quaternary hemipelagic sediments of the Japan Sea recovered during IODP Expedition 346. Progress in Earth and Planetary Science (2018).
5. East Asian Monsoon History and Paleoceanography of the Japan Sea Over the Last 460,000 Years. Paleoceanography and Paleoclimatology (2018).
6. Construction of perfectly continuous records of physical properties for dark-light sediment sequences collected from the Japan Sea during Integrated Ocean Drilling Program Expedition 346 and their potential utilities as paleoceanographic studies. Progress in Earth and Planetary Science (2018).
7. The Pliocene to recent history of the Kuroshio and Tsushima Currents: a multi-proxy approach. Progress in Earth and Planetary Science (2015).
8. Palaeoceanography of the Japan Sea Across the Mid‐Pleistocene Transition: Insights From IODP Exp. 346, Site U1427. Paleoceanography and Paleoclimatology (2022).