210Pb and 137Cs measurements in the Circum Bohai Sea coastal region: sedimentation rates and implications

Abstract

The representative 210 Pb and 137 Cs age-depth profiles were selected from more than 100 sites in the Circum Bohai Sea (CBS) coastal region to examine the sedimentation rates and associated environmental changes. There are three unique 210 Pb exc distribution patterns: 1) ideal-decaying type, representing relatively constant sediment supply and quieter environmental setting; 2) wiggling type, but with approximately equivalent amplitude, representing coarser sediments and associated stronger flow current environment; and 3) episodic-eventinfluencing type, each representing typhoon storm-influenced depositional environment. Our results also show that there is a lower sedimentation rate (ca. 0.1 cm/a) in the coastal lowlands, a higher sedimentation rate (ca. 0.5-3 cm/a) in the intertidal flat and an intermediate rate of ca. 0.58 cm/a in the subtidal zone near the Huanghua Harbor. The interbedded silt layer occurring in the core sediment reveals lower 210 Pb activities, indicating a discontinuous sedimentation mostly due to typhoon events which dwarfs against 210 Pb and 137 Cs applicability. Overall, the 210 Pb and 137 Cs measurements of the present study provide physical insight into the evaluation of the coastal-marine ecological environment and associated management.

Mercury Inputs to Chinese Marginal Seas: Impact of Industrialization and Development of China

“…The constant rate of 210 Pb supply (CRS) model was used to calculate the sedimentation rates. The CRS model, which is suitable for a system where the transfer of 210 Pb to sediments is very efficient (e.g., large water bodies with long hydraulic retention times) (Appleby et al, ), has been widely used by previous studies in Chinese marginal seas (Guo et al, ; Ip et al, ; Li et al, ; Wang et al, ). The sediment fluxes were calculated using the outputs of the CRS model and the dry weight test (Ip et al, ; Li et al, ).…”

Unraveling Environmental Forces Shaping Surface Sediment Geochemical “Isodrapes” in the East Asian Marginal Seas

“…Region I in the north is a small enclosed shallow marginal sea that encompasses the Bohai Sea, with a mean water depth of 18 m. Sedimentation rates in this region are highest offshore the Yellow River (Huanghe) (Hu et al., 2011) given its high sediment discharge, with a sediment yield of 150 Mt yr −1 (Milliman & Farnsworth, 2011) (Figure 1), and decrease with distance from the river mouth to 0.15 cm yr −1 (Wang et al., 2008) (Table 1). Weakening of tidal currents in the center of this region promotes the formation of mud deposits enriched in OC (Zhao et al., 2021; Zhu & Chang, 2000).…”