A Multinational Green Supply Chain Model Suffered to Import Tariff

This paper considers a multinational green supply chain (MGSC), composed of a manufacturer and a foreign retailer affected by import tariff. The main theme of this paper is to explore supply chain decisions and coordination contract. Four decision models were investigated: (1) the centralized decision supply chain model (model CS), (2) the decentralized decision supply chain model (model DS), (3) the R&D cost sharing contract model (model RD) with the retailer sharing a portion of green R&D cost, and (4) the quantity discount-cost sharing contract model (model QD), which combined a quantity discount contract with a cost sharing contract. The equilibrium decisions of these models were derived. The R&D cost sharing contract was found to improve greenness and performance of the supply chain but cannot reach the optimal performance compared to the centralized decision model. While the quantity discount-cost sharing contract can achieve a perfect coordination of MGSC. Furthermore, import tariff has an adverse effect on the performance of MGSC. The increase in tariff shrinks the threshold of the highest wholesale price and quantity discount coefficient offered by the manufacturer, which will hamper the cooperation of supply chain. However, the enhancement of consumers’ green preference is conducive to encourage the retailer to participate in cooperation and smoothen the adverse effects of tariff fluctuation. In the same model, the adverse effect of tariff on product greenness and the retail price does not change with the increase in its value. However, the adverse effect on the green performance price ratio and the profits from all parties in the supply chain are slow

Holocene Paleoclimate Records in Equatorial West Africa: Insights Based on the Characterization of Glycerol Dialkyl Glycerol Tetraethers

One gravity core retrieved from the Niger Delta was used to explore the origin of deposited organic matter (OM) and the paleo-climatic and environmental conditions over the Holocene in equatorial West Africa. The geochemical properties of sediments including glycerol dialkyl glycerol tetraethers (GDGTs) and elemental (%OC, %N, C/N) and isotopic (δ13Corg, δ15N) signatures were determined. The determination constrained the age of the column and revealed that the sediment OM was mainly derived from a marine source. The isoprenoid (iso)GDGTs were the dominant GDGTs, with a small amount of branched (br)GDGTs, which led to a low-branched and isoprenoid tetraether index (BIT, 0.02–0.21) and represented a low terrestrial input. Most isoGDGTs and OH-GDGTs were produced in situ by Marine Group I (MG-I) Thaumarchaeota, while the brGDGTs were mainly transported from land. A two-endmember model quantified the contribution of terrestrial OM, as 0.9–19.9% by BIT and 1.1–32.6% by δ13C. Accordingly, the millennium-scale sea surface temperatures (SSTs) were reconstructed based on the cyclopentane ring distribution (TEX86H) and the ring index of OH-GDGTs (RI-OH). The top core SSTs were lower than the modern mean annual SST due to the growth season and habitat depth of Thaumarchaeota. The reconstructed SSTs clearly revealed the four stages of paleoclimate change, in particular, the drought episode of 8.2 kyr and the following humid period. The above research has enhanced our understanding of the paleoclimate change in river outflow during the Holocene at the millennium scale

Variability of Microbial Community Structure Distribution in Marine Shallow Surface Sediments in Shenhu Area

Due to the frequent exchange of matter and energy between living and non-living matter in seawater, the surface layer, particularly the distribution of microorganisms in centimeter-scale and element concentrations in surface sediments, demonstrates the important message of the local biogeochemical environment. This work probed the differences in microbial communities between two sampling cores obtained from the same area and the possible environmental factors, e.g., in situ component and concentration in porewater. Here, high-throughput sequencing (16S rRNA, Illumina sequencing) and quantitative PCR analysis were used to investigate the diversity of microorganisms in sediments of two push cores of L1 and S8 from Shenhu Area, South China Sea. Porewater concentration of components and isotopic fractionation were also obtained to explore the possible correlation between the microbial community and the chemical compositions of porewater. Q-PCR revealed bacteria play an important role in the geochemical cycle in the surface sediments, and archaea may be the main community in response to environmental changes and maintain the local marine ecosystem. The total gene copies of microorganisms in the study area were lower than nearby marine sediments. Microbial community compositions showed the dominant microbial phyla were similar on Phylum level in L1 and S8, with only different abundances. Firmicutes and Proteobacter were the main bacterial phyla, while Thaumarchaeota, Lokiarchaeota and Bathyarchaeota dominated the archaeal community. The abundance of the dominant class varied significantly between L1 and S8. Bacilli in Firmicutes and Gammaproteobacteria in Proteobacter were prevalent bacterial class, MGI in Thaumarchaeota was the predominant archaeal class in L1, while Thermoplasmata and Group-C3 dominated in S8. PCoA results showed a clear diversity of bacterial and archaeal communities between these two sites, as well as significant geographic variation in microbial communities. RDA results revealed that a complex combination of environmental factors might correlate to microbial communities in a marine dynamic environment. Here, delta C-13(DIC), DIC and SO42- were strongly correlated to the bacterial communities, whereas delta C-13(DIC), Fe2+ and SO42- concentration linked to archaeal communities. Microbial communities and RDA results suggested carbon may be the main factor related to the microbial community in L1, while Fe2+ correlated with microbial community composition in S8. SO42- concentration and the distribution of Gammaproteobacteria indicated that the sulfur cycle is probably active in this area