Wet and cold climate conditions recorded by coral geochemical proxies during the beginning of the first millennium CE in the northern South China Sea

Abstract

The past two millennia include some distinct climate intervals, such as the Medieval Warm Period (MWP) and the Little Ice Age (LIA), which were caused by natural forcing factors, as well as the Current Warm Period (CWP) that has been linked to anthropogenic factors. Therefore, this period has been of great interest to climate change researchers. However, most studies are based on terrestrial proxy records,

Episodic Reef Growth in the Northern South China Sea linked to Warm Climate During the Past 7,000 Years: Potential for Future Coral Refugia

“…The pink‐shaded bars and blue‐shaded bars represent warm periods and cold periods, respectively. (b) Sr/Ca‐SST (red dots: mean maximum SST, orange dots: mean annual SST, and green dots: mean minimum SST) and (c) Δδ 18 O of the SCS recorded by corals from Leizhou (Yu et al, ), Sanya (Guo et al, ; Wei et al, ), and Qionghai (Deng et al, ; Xiao et al, ). Note: SSTs of Leizhou and Qionghai were corrected for better comparison with those of Sanya using their modern SST differences; Δδ 18 O values were calculated from coral δ 18 O values after subtracting the effect of temperature, reflecting SSS variation.…”

“…To identify potential climatic and environmental drivers of switch‐on and switch‐off events, we compared coral age distributions to marine paleoenvironmental conditions in the region during the past 7,000 years. Sr/Ca ratios, Δδ 18 O values, and Δ R (localized marine reservoir correction) values of dated Porites from reefs within the northern SCS including Leizhou Peninsula, Qionghai, Sanya, and Yongshu reef (Deng et al, ; Guo et al, ; Wei et al, ; Xiao et al, ; Yu et al, ; Yu et al, ) were compiled as proxies for SST, SSS (or sea surface evaporation/transportation of moisture to higher latitude, Gagan et al, ), and upwelling intensity, respectively (Figures b–d). To identify the evolutionary history of Luhuitou reef, relative sea level (RSL) curves of the SCS were compiled from reconstructed fossil microatolls (Yu, ), in situ Porites (Nguyen, ), and oysters (Baker et al, ; Figure e).…”

Coral Paleoclimate Perspectives Support the Role of Low‐Latitude Forcing on the 4.2 ka BP Event

“…Wang et al, 2022) and (i) brGDGT records (M. Wang et al, 2017) from Shuizhuyang peat deposit, and (j) peat humification (light pink) and dry density (deep pink) from Daping Swamp (Zhong et al, 2015); northern SCS: (k) Δδ 18 O anomaly and (l) Sr/Ca-SSTA records from Porites corals (this study and Wei et al, 2004Wei et al, , 2007Yu et al, 2005;Y. Guo et al, 2016;Deng et al, 2017;Xiao et al, 2017Xiao et al, , 2021. The gray bar marks a likely prolonged period of the 4.2 ka BP event as suggested by coral records.…”

The CoralHydro2k Database: a global, actively curated compilation of coral δ18O and Sr / Ca proxy records of tropical ocean hydrology and temperature for the Common Era

“…Approximately 28% of records in the database cover time intervals earlier than the 1800s, with most of these records coming from corals that are dead when collected (often referred to as "fossil" corals), which provide short, discrete time series often spanning several decades. The oldest such record in the database is a coral from Hainan Island in the South China Sea that covers 167-309 CE (Xiao et al, 2017). A surge in coral-based proxy record generation began in the early 1990s and is reflected in the most common coretop ages occurring in the period from 1990 to 2015 CE (Fig.…”