Sedimentary Response to Climate Change in the Central Bay of Bengal since the Last Glacial Maximum

AbstractAs the largest submarine fan, the Bay of Bengal (BoB) captures the abundant environment and climate fingerprints on different time scales. To investigate the sedimentary response to climate change since the Last Glacial Maximum (LGM), an integrated survey was performed to study grain size, major, and trace elements (Al2O3, CaO, K2O, Na2O, TiO2, Sr, and Rb) of core BoB-24 sediments from the central BoB. The (K/Al)-TiO2 (%) relationship of the sediments was taken for the discrimination of provenance, which indicated that sediments from core BoB-24 in 24~6.5 cal ka BP were primarily from terrigenous material input from the Himalayas. In contrast, the material contribution from the Indian subcontinent increased distinctly since 6.5 cal ka BP. The rising sea level severed direct material supply, thus causing the evolution of sediment provenance of the central BoB. Meanwhile, the strengthened Indian summer monsoon (ISM) in the Holocene affected detrital material transport from offshore to the central BoB. After understanding the sediment provenance in the study, we choose the sensitive grain-size fraction to show the evolution of hydrodynamic conditions. The chemical index of alteration (CIA) and Ti/Ca and Rb/Sr ratios are calculated to indicate the change in terrigenous input and weathering intensity. The contents of sediment fraction from 11.05 to 15.63 μm, CIA, and ratios of Ti/Ca and Rb/Sr in core BoB-24 showed the same trends, which were low during the last deglaciation and late Holocene but high in the Early Holocene. The trends were strongly correlated with the variation of the Indian summer monsoon, indicating the possible impact of Indian monsoon on sediment transport in the Bay of Bengal. Alternative indicators such as the contents of ratios of Ti/Ca and Rb/Sr, CIA, and sensitive grain-size content in sediments of core BoB-24 jointly record the evolution history of ISM since 24 ka BP in the Bay of Bengal. Although the sensitivity and response of each indicator to the paleoenvironment and paleoclimate change are slightly different, on the whole, the change trend is the same. Specifically, four warm-cold alternating periods (Heinrich Event 1, Bølling/Allerød, Younger Dryas, and Early Holocene Climatic Optimum) had a strong signal in these proxies that indicated that the millennial-scale climate controls the terrigenous input to the Bay of Bengal, where a high value occurs in warm events and low value in cold events. The sedimentary pattern of the northeastern Indian Ocean provides scientific evidence for an insight into the regional response to global climate change and the long-term climate change trend of the human environment across the monsoon region

The complete chloroplast genome sequence of Trollius macropetalus

The complete chloroplast genome of Trollius macropetalus was sequenced in this study. It has a cyclic tetrad structure typical of angiosperms. The total length is 160,094 bp, including a large single copy region (LSC) with a length of 88,555 bp, a small single copy region (SSC) with a length of 18,291 bp and two equal-length inverted repeat regions (IRA/IRB) with a length of 26,624 bp. It encodes a total of 137 genes, including 87 protein-coding genes, 42 tRNA genes, and 8 rRNA genes, with a CG content of 38.03%

Grain size records reveal variability of the East Asian Winter Monsoon since the Middle Holocene in the Central Yellow Sea mud area, China

Three cores (ZY-1, ZY-2 and ZY-3) retrieved from the Central Yellow Sea mud (CYSM) were analyzed in sensitive grain size and AMS 14C dating to reconstruct the history of the East Asian Winter Monsoon (EAWM) since the Middle Holocene in the study area. The results show that these data provide a continuous history of the EAWM over the past 7. 2 ka and that the EAWM can be divided into three periods: strong and highly fluctuating during 7. 2-4. 2 ka BP; moderate and relatively stable during 4. 2-1. 8 ka BP; and weakened during 1. 8-0 ka BP. Compared with the East Asian Summer Monsoon (EASM) recorded in the previous studies, the evolutionary history of the EAWM broadly follows the orbital-derived winter insolation with a similar long-term step-decreased trend as the EASM. At the centennial scale, however, the EAWM intensified events correlate well with the EASM weakened events and the North Atlantic climatic variations (Bond events 0 to 5) within the dating error, most likely forced by the reduction of solar irradiance through changes in the oceanic-atmospheric circulation patterns.</p

Sedimentation and lateral transport of Pb-210 over the East China Sea Shelf

Chinese COMRA program [DY125-13-E-01]; Chinese National Science Foundation [41076043, 41125020]Pb-210 is an effective tracer of constraining particle transport and sedimentation in shelf regions. To reveal the spatial pattern of Pb-210 over the East China Sea (i.e. ECS) Shelf, Pb-210 in the surface sediments were examined at 11 stations, as well as Th-234 and Pb-210 in the water column at four stations. Overall, the plume zone of the Yangtze River along the coastline is a source area of Pb-210 for the outer shelf, exporting 0.46 dpm cm(-2) year(-1) at least, which accounts for about 25 % of Pb-210 input into this region. In the southern ECS Shelf to the north of the Taiwan Strait, the focusing factor (f) values are higher than unity, indicating a sink area of Pb-210. Boundary scavenging of Pb-210 contributes 0.36 dpm cm(-2) year(-1) to this sink area on the basis of a mass balance model evaluation. Lateral transport of Pb-210 to this region, quantified by Th-234 and Pb-210 in the water column, varied from 3.34 to 6.39 dpm cm(-2) year(-1) with an average of 4.83 dpm cm(-2) year(-1), also supporting its sink characteristic. To the southwest of the Cheju Island, the f values were less than unity, revealing a source region of Pb-210. The average export flux of Pb-210 from this region was 1.64 dpm cm(-2) year(-1). Therefore, Pb-210 sedimentation/settling showed significantly heterogeneous sedimentation of particulate matter over the ECS Shelf

Development of an ELISA Assay for the Determination of SARS-CoV-2 Protein Subunit Vaccine Antigen Content

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) protein subunit vaccine is one of the mainstream technology platforms for the development of COVID-19 vaccines, and most R&D units use the receptor-binding domain (RBD) or spike (S) protein as the main target antigen. The complexity of vaccine design, sequence, and expression systems makes it urgent to establish common antigen assays to facilitate vaccine development. In this study, we report the development of a double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) to determine the antigen content of SARS-CoV-2 protein subunit vaccines based on the United States Pharmacopeia and ICH (international conference on harmonization) Q14 and Q2 (R2) requirements. A monoclonal antibody (mAb), 20D8, was identified as the detection antibody based on its high RBD binding activity (EC50 = 8.4 ng/mL), broad-spectrum anti-variant neutralizing activity (EC50: 2.7–9.8 ng/mL for pseudovirus and EC50: 9.6–127 ng/mL for authentic virus), good in vivo protection, and a recognized linear RBD epitope (369–379 aa). A porcine anti-RBD polyclonal antibody was selected as the coating antibody. Assay performance met the requirements of the analytical target profile with an accuracy and precision of ≥90% and adequate specificity. Within the specification range of 70–143%, the method capability index was >0.96; the misjudgment probability was <0.39%. The method successfully detected SARS-CoV-2 protein subunit vaccine antigens (RBD or S protein sequences in Alpha, Beta, Gamma, or Delta variants) obtained from five different manufacturers. Thus, we present a new robust, reliable, and general method for measuring the antigenic content of SARS-CoV-2 protein subunit vaccines. In addition to currently marketed and emergency vaccines, it is suitable for vaccines in development containing antigens derived from pre-Omicron mutant strains