Holocene salinity fluctuations of the East Korean lagoon related to sea level and precipitation changes

Abstract

Detailed diatom records within core sediments from Maeho Lagoon along the Eastern coast of South Korea revealed that the ecological dynamics of the lagoon during the Holocene were associated with relative sea level and regional precipitation. Accelerator mass spectrometry (AMS) 14C dating indicates that sediment accumulation began prior to 8300 cal. year BP, and that the lagoon formed around 8000 cal. year BP. The salinity level of the lagoon increased until 5000 cal. year BP, and then decreased. Long‐term trends in salinity were dependent upon changes in sea level: periods of high salinity in the lagoon were generally coincident with periods of high sea levels along the east coasts of Korea and Japan. On the other hand, multicentennial‐scale fluctuations in diatom assemblages and magnetic susceptibility (MS) suggest that a 400 year fluctuation in salinity was regulated by changes in precipitation in the area of this lagoon. Changes in the westerly jet stream, controlled by variation in solar irradiance, had an important influence on precipitation volume in South Korea, suggesting that the patterns of the westerly jet stream fluctuate on a 400 year cycle.

Mid- to late Holocene cooling events in the Korean Peninsula and their possible impact on ancient societies

“…Here, we present a multiproxy record using pollen, magnetic susceptibility (MS), carbon isotopic composition (δ 13 C), carbon/nitrogen ratio (C/N), and particle size of mid- to late Holocene environmental changes based on a sediment core from the Pomaeho lagoon on the east coast of Korea. Recently, diatom records have been produced from the same site to explore changes in relative sea level and local precipitation (Katsuki et al, 2017). In this study, we investigate abrupt cooling events during the mid- to late Holocene and their possible impacts on ancient human societies.…”

Evolution of the paleo-Daesan Bay (Nakdong River, South Korea) as a result of Holocene sea level change

“…From the regional viewpoint of sea level rise in spatial and temporal terms, changes should have simultaneously influenced coastal areas and inland paleo-bay areas. This process involves shifts from freshwater-dominant to marine-dominant environments due to Holocene sea level rise (Stanley and Warne, 1994; Hori et al, 2004; Kim et al, 2012; Tanigawa et al, 2013; Lambeck et al, 2014, and references therein; Cho et al, 2017; Katsuki et al, 2017; Xiong et al, 2020). To trace specific geomorphological-geochemical settings (e.g., intertidal, estuary, and inner bay) that formed in response to sea level changes, information about sea level in previous times and paleo-water depth in the study area is essential (e.g., Lim et al, 2015, 2019).…”

“…Long-term environmental changes in Daesan Basin and possible links to Holocene regional sea level changes From the perspective of Holocene coastal evolution, marine transgression is an important feature of present coastal areas in East Asia, resulting in remarkable shifts from freshwater-dominant to marine-dominant environments due to Holocene sea level rise (Hori et al, 2004;Kim et al, 2012;Tanigawa et al, 2013;Cho et al, 2017;Katsuki et al, 2017;Xiong et al, 2020). Efforts to reconstruct regional sea level changes in East and South Asian coastal areas have been made.…”

“…In recent decades, many studies have focused on reconstruction of past sea level changes and their influences on geomorphological changes. Some studies have successfully redrawn past coastlines and geomorphological changes based on reconstructed sea level changes (Stanley and Warne, 1994; Nguyen et al, 1998; Kato et al, 2003; Nahm et al, 2008; Yang et al, 2008; Ishihara et al, 2012; Tanigawa et al, 2013; Lambeck et al, 2014, and references therein; Katsuki et al, 2017; Xiong et al, 2020). Regarding Neolithic cultures, Holocene sea level transgression and climate changes were clearly linked to various early Neolithic settlements in East Asia (Zong et al, 2011; Li et al, 2018; Innes et al, 2019; Sun et al, 2019; Huang et al, 2021).…”

Fossil diatom assemblage changes due to paleoenvironment change, tsunami, and typhoon in southern Japan

“…Concurrent peaks in S counts and the brackish and halophilic planktonic species, C. atomus var. gracilis (salinity of 15-20 ‰; Katsuki, Nakanishi, et al, 2017;Genkal & Kiss, 1993) just above the C.E. 1281 layer also suggest a potential inlet breach, either due to marine flooding associated with the event or subsequent inlet formation due to the draining of excess freshwater infilling the lake (Figures 2 and 4a).…”