Description: Perfluoroalkyl acids (PFAAs) have been determined in the environment globally. However, studies on the occurrence of PFAAs in marine sediment remain limited. In this study, 16 PFAAs are investigated in surface sediments from the German Bight, which provided a good overview of the spatial distribution. The concentrations of Sum PFAAs ranged from 0.056 to 7.4 ng/g dry weight. The highest concentration was found at the estuary of the River Ems, which might be the result of local discharge source. Perfluorooctane sulfonic acid (PFOS) was the dominant compound and the enrichment of PFOS in sediment might be strongly related to the compound structure itself. The geographical condition of the German Bight influenced the movement of water and sediment, resulting in complex distribution. Following normalization according to total organic carbon (TOC) content, PFAA distributions showed a different picture. Significant linear relationships were found between total PFAA concentrations and TOC (R**2 = 0.50, p b 0.01). Compared with a previous study conducted in the same area, a declining trend was presented for the concentrations of PFOS and perfluorooctanoic acid (PFOA). Compound structure, geographical condition, and organic carbon in the sediment influence the distribution of PFAAs in the German Bight. Environmental risk assessment indicated that the risk from PFOA is negligible, whereas PFOS in marine sediment may present a risk for benthic organisms in the German Bight.

Description: Lipid compositions of sediments recovered during Ocean Drilling Program Leg 184 in the South China Sea have been identified and quantified. The identified lipids can be ascribed to terrigenous and marine sources. Terrigenous lipids are mainly C27, C29, C31 n-alkanes, C26, C28, C30 n-fatty acids, and n-alcohols, which were derived from leaf waxes of higher land plants and transported to the sea by airborne dust or fresh water. Marine lipids, mainly C37 and C38 alkenones, C30 diol, and C30 and C32 keto-ols, were from microalgae, notably haptophytes and eustigmatophytes. Elevated concentrations and accumulation rates of both terrigenous and marine lipids in the interval 202-245 meters composite depth (mcd) and 0-166 mcd were postulated to be related to the development of the East Asian monsoon at 6-8 Ma and enhanced variations of the developed East Asian monsoon after 3.2 Ma, respectively. The pronounced late Oligocene input of terrigenous lipids reflects the paleoenvironment of a newly opened, narrow basin, with restricted ocean waters and the proximity of continental runoff.

Description: The Journal of Physical Chemistry B DOI: 10.1021/jp409021q

Description: Environmental Science & Technology DOI: 10.1021/es302037t

Description: Background: Banana and plantain (Musa spp.) comprise an important part of diets for millions of people around the globe. Low temperature is one of the key environmental stresses which greatly affects the global banana production. To understand the molecular mechanism of the cold-tolerance in plantain we used RNA-Seq based comparative transcriptomics analyses for both cold-sensitive banana and cold-tolerant plantain subjected to the cold stress for 0, 3 and 6 h. Results: The cold-response genes at early stage are identified and grouped in both species by GO analysis. The results show that 10 and 68 differentially expressed genes (DEGs) are identified for 3 and 6 h of cold stress respectively in plantain, while 40 and 238 DEGs are identified respectively in banana. GO classification analyses show that the majority of DEGs identified in both banana and plantain belong to 11 categories including regulation of transcription, response to stress signal transduction, etc. A similar profile for 28 DEGs was found in both banana and plantain for 6 h of cold stress, suggesting both share some common adaptation processes in response to cold stress. There are 17 DEGs found uniquely in cold-tolerance plantain, which were involved in signal transduction, abiotic stress, copper ion equilibrium, photosynthesis and photorespiration, sugar stimulation, protein modifications etc. Twelve early responsive genes including ICE1 and MYBS3 were selected and further assessed and confirmed by qPCR in the extended time course experiments (0, 3, 6, 24 and 48 h), which revealed significant expression difference of key genes in response to cold stress, especially ICE1 and MYBS3 between cold-sensitive banana and cold-tolerant plantain. Conclusions: We found that the cold-tolerance pathway appears selectively activated by regulation of ICE1 and MYBS3 expression in plantain under different stages of cold stress. We conclude that the rapid activation and selective induction of ICE1 and MYBS3 cold tolerance pathways in plantain, along with expression of other cold-specific genes, may be one of the main reasons that plantain has higher cold resistance than banana.

Description: Author(s): Ziyang Chen, Yichen Zhang, Gan Wang, Zhengyu Li, and Hong Guo Measurement-device-independent quantum key distribution protocol, whose security analysis does not rely on any assumption on the detection system, can immune the attacking against detectors. We give a first composable security analysis for continuous-variable measurement-device-independent quantum k... [Phys. Rev. A 98, 012314] Published Fri Jul 13, 2018