scholarly journals Acrylic acid and related dimethylated sulfur compounds in the Bohai and Yellow Seas during summer and winter

2019 ◽  
Author(s):  
Xi Wu ◽  
Pei-Feng Li ◽  
Hong-Hai Zhang ◽  
Mao-Xu Zhu ◽  
Chun-Ying Liu ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Bohai Sea ◽  
Average Concentration ◽  
Sulfur Compounds ◽  
The Yellow Sea ◽  
Bacterial Metabolism ◽  
The North ◽  
Terrestrial Inputs ◽  
Spatio Temporal ◽  
Microbial Consumption

Abstract. Spatio-temporal distributions of acrylic acid (AA) and related biogenic sulfur compounds including dimethylsulfide (DMS) and dissolved and total dimethylsulfoniopropionate (DMSPd and DMSPt) were investigated in the Bohai Sea (BS) and the Yellow Sea (YS) during summer and winter. AA and DMS production from DMSPd degradation and AA degradation were studied. Significant seasonal variations of AA and DMS(P) were observed. AA presented similar distributions during summer and winter, that is, relatively high values of AA emerged in the BS and the north YS and concentrations decreased from inshore to offshore areas in the south YS. Due to strong biological production from DMSP and abundant terrestrial inputs from rivers in summer, AA concentrations at surface were higher during summer (30.01 nmol L−1) than during winter (14.98 nmol L−1). The average concentration sequence AA>DMSPt>DMS>DMSPd at transects during summer illustrated particulate DMSP (DMSPp) as a DMS producer and terrestrial sources of AA, whereas the sequence in winter was AA>DMSPt>DMSPd>DMS. High values of AA and DMS(P) were mostly observed in the upper layers with occasional high values at bottom. High AA concentrations in porewater which could be transported into the bottom water might result from the cleavage of intracellular DMSP and reduce bacterial metabolism in sediments. In addition, the degradation/production rates of biogenic sulfur compounds were obviously higher in summer than in winter and the removal of AA was mainly attributed to the microbial consumption. Other sources of AA besides the production from DMSPd was also proved.

scholarly journals Acrylic acid and related dimethylated sulfur compounds in the Bohai and Yellow seas during summer and winter

2020 ◽  
Vol 17 (7) ◽  
pp. 1991-2008 ◽  
Author(s):  
Xi Wu ◽  
Pei-Feng Li ◽  
Hong-Hai Zhang ◽  
Mao-Xu Zhu ◽  
Chun-Ying Liu ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Bottom Water ◽  
Bohai Sea ◽  
Average Concentration ◽  
Sulfur Compounds ◽  
Bacterial Metabolism ◽  
Surface Seawater ◽  
Degradation Rates ◽  
Terrestrial Inputs ◽  
Microbial Consumption

Abstract. Spatiotemporal distributions of dissolved acrylic acid (AAd) and related biogenic sulfur compounds including dimethylsulfide (DMS) and dissolved and total dimethylsulfoniopropionate (DMSPd and DMSPt) were investigated in the Bohai Sea (BS) and Yellow Sea (YS) during summer and winter. AAd and DMS production from DMSPd degradation and AAd degradation were analyzed. Significant seasonal variations in AAd and DMS(P) were observed. AAd exhibited similar distributions during summer and winter; i.e., relatively high values of AAd occurred in the BS and the northern YS, and the concentrations decreased from inshore to offshore areas in the southern YS. Due to strong biological production from DMSP and abundant terrestrial inputs from rivers in summer, the AAd concentrations in the surface seawater during summer (30.01 nmol L−1) were significantly higher than those during winter (14.98 nmol L−1). The average concentration sequence along the transects during summer (AAd > DMSPt > DMS > DMSPd) showed that particulate DMSP (DMSPp) acted as a DMS producer and that terrestrial sources of AAd were present; in contrast, the sequence in winter was AAd > DMSPt > DMSPd > DMS. High values of AAd and DMS(P) were mostly observed in the upper layers, with occasional high values at the bottom. High AAd concentrations in the porewater, which could be transported to the bottom water, might result from the cleavage of intracellular DMSP and reduce bacterial metabolism in sediments. In addition, the production and degradation rates of biogenic sulfur compounds were significantly higher in summer than in winter, and the removal of AAd was primarily attributed to microbial consumption. Other sources of AAd existed aside from the production from DMSPd.

Biogeochemistry of dimethylsulfoniopropionate, dimethylsulfide and acrylic acid in the Yellow Sea and the Bohai Sea during autumn

2016 ◽  
Vol 13 (1) ◽  
pp. 127 ◽  
Author(s):  
Yue Liu ◽  
Chun-Ying Liu ◽  
Gui-Peng Yang ◽  
Hong-Hai Zhang ◽  
Sheng-hui Zhang
Keyword(s):  
Acrylic Acid ◽  
Chlorophyll A ◽  
Yellow Sea ◽  
Bohai Sea ◽  
Sulfur Cycle ◽  
The Yellow Sea ◽  
Trace Gas ◽  
The Bohai Sea ◽  
Marginal Seas ◽  
High Concentrations

Environmental context Dimethylsulfide (DMS) is a climatically important biogenic trace gas that is emitted from oceans. This research focuses on the spatiotemporal distributions of DMS and its related compounds, i.e. dimethylsulfoniopropionate (DMSP) and acrylic acid (AA), and the influencing factors in the Yellow Sea and the Bohai Sea during autumn. In addition, the sea-to-air flux of DMS, kinetic responses of DMSP consumption as well as DMS and AA production are also investigated. This study is helpful in understanding the marine sulfur cycle in marginal seas in China. Abstract The biogeochemistry of dimethylsulfoniopropionate (DMSP), dimethylsulfide (DMS) and acrylic acid (AA) in the Yellow Sea (YS) and the Bohai Sea (BS) was investigated in November 2013. The concentrations (and ranges) of total DMSP (DMSPt), dissolved DMSP (DMSPd), DMS and AA in surface waters were 30.71 (1.07–122.50), 6.60 (0.85–35.67), 1.48 (0.53–5.32) and 42.2 (13.8–352.8) nmol L–1 respectively. The concentrations of DMSPd and AA were positively correlated with chlorophyll-a levels, which suggests that phytoplankton biomass has an important function in controlling DMSPd and AA distributions. Furthermore, DMS and AA concentrations revealed significant positive relationships with DMSPd concentrations. The average ratios of AA/(DMSP+AA) and DMS/AA were 53.98 and 7.62% respectively. The vertical profiles of DMSP, DMS and AA were characterised by high concentrations that mostly occur near the surface. Even under highly variable hydrographic conditions, a positive relationship was observed between DMSPt and chlorophyll-a concentrations. The rates of DMSPd consumption, as well as DMS and AA production, significantly varied with marine environments. The sea-to-air fluxes of DMS from the YS and the BS to the atmosphere were estimated to be in the range of 3.01 to 6.91μmol m–2day–1.

Distribution, Occurrence, and Fate of Biogenic Dimethylated Sulfur Compounds in the Yellow Sea and Bohai Sea During Spring

2019 ◽  
Vol 124 (8) ◽  
pp. 5787-5800
Author(s):  
Feng Xu ◽  
Na Jin ◽  
Zhun Ma ◽  
Hong‐Hai Zhang ◽  
Gui‐Peng Yang
Keyword(s):  
Yellow Sea ◽  
Bohai Sea ◽  
Sulfur Compounds ◽  
The Yellow Sea

scholarly journals Modelling local patterns of child mortality risk: a Bayesian Spatio-temporal analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Alejandro Lome-Hurtado ◽  
Jacques Lartigue-Mendoza ◽  
Juan C. Trujillo
Keyword(s):  
High Risk ◽  
Mexico City ◽  
Child Mortality ◽  
Mortality Risk ◽  
Temporal Analysis ◽  
Health Concern ◽  
The North ◽  
Greater Mexico ◽  
Spatio Temporal ◽  
Child Mortality Rate

Abstract Background Globally, child mortality rate has remained high over the years, but the figure can be reduced through proper implementation of spatially-targeted public health policies. Due to its alarming rate in comparison to North American standards, child mortality is particularly a health concern in Mexico. Despite this fact, there remains a dearth of studies that address its spatio-temporal identification in the country. The aims of this study are i) to model the evolution of child mortality risk at the municipality level in Greater Mexico City, (ii) to identify municipalities with high, medium, and low risk over time, and (iii) using municipality trends, to ascertain potential high-risk municipalities. Methods In order to control for the space-time patterns of data, the study performs a Bayesian spatio-temporal analysis. This methodology permits the modelling of the geographical variation of child mortality risk across municipalities, within the studied time span. Results The analysis shows that most of the high-risk municipalities were in the east, along with a few in the north and west areas of Greater Mexico City. In some of them, it is possible to distinguish an increasing trend in child mortality risk. The outcomes highlight municipalities currently presenting a medium risk but liable to become high risk, given their trend, after the studied period. Finally, the likelihood of child mortality risk illustrates an overall decreasing tendency throughout the 7-year studied period. Conclusions The identification of high-risk municipalities and risk trends may provide a useful input for policymakers seeking to reduce the incidence of child mortality. The results provide evidence that supports the use of geographical targeting in policy interventions.

scholarly journals Nitric oxide (NO) in the Bohai Sea and the Yellow Sea

2019 ◽  
Vol 16 (22) ◽  
pp. 4485-4496 ◽  
Author(s):  
Ye Tian ◽  
Chao Xue ◽  
Chun-Ying Liu ◽  
Gui-Peng Yang ◽  
Pei-Feng Li ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Surface Layer ◽  
Yellow Sea ◽  
Bohai Sea ◽  
Limit Of Detection ◽  
Bottom Layer ◽  
The Yellow Sea ◽  
The Bohai Sea ◽  
Significant Difference ◽  
Average Flux

Abstract. Nitric oxide (NO) is a short-lived compound of the marine nitrogen cycle; however, our knowledge about its oceanic distribution and turnover is rudimentary. Here we present the measurements of dissolved NO in the surface and bottom layers at 75 stations in the Bohai Sea (BS) and the Yellow Sea (YS) in June 2011. Moreover, NO photoproduction rates were determined at 27 stations in both seas. The NO concentrations in the surface and bottom layers were highly variable and ranged from below the limit of detection (i.e., 32 pmol L−1) to 616 pmol L−1 in the surface layer and 482 pmol L−1 in the bottom layer. There was no significant difference (p>0.05) between the mean NO concentrations in the surface (186±108 pmol L−1) and bottom (174±123 pmol L−1) layers. A decreasing trend of NO in bottom-layer concentrations with salinity indicates a NO input by submarine groundwater discharge. NO in the surface layer was supersaturated at all stations during both day and night and therefore the BS and YS were a persistent source of NO to the atmosphere at the time of our measurements. The average flux was about 4.5×10-16 mol cm−2 s−1 and the flux showed significant positive relationship with the wind speed. The accumulation of NO during daytime was a result of photochemical production, and photoproduction rates were correlated to illuminance. The persistent nighttime NO supersaturation pointed to an unidentified NO dark production. NO sea-to-air flux densities were much lower than the NO photoproduction rates. Therefore, we conclude that the bulk of the NO produced in the mixed layer was rapidly consumed before its release to the atmosphere.

scholarly journals Spatio-Temporal Characteristics and Obstacle Factors of the Urban-Rural Integration of China’s Shrinking Cities in the Context of Sustainable Development

2021 ◽  
Vol 13 (8) ◽  
pp. 4203
Author(s):  
Bin Du ◽  
Ying Wang ◽  
Jiaxin He ◽  
Wai Li ◽  
Xiaohong Chen
Keyword(s):  
Sustainable Development ◽  
Economic Efficiency ◽  
Formation Mechanisms ◽  
Shrinking Cities ◽  
The Sustainable Development ◽  
Factors Affecting ◽  
Temporal Characteristics ◽  
The North ◽  
Urban Rural ◽  
Spatio Temporal

Based on the fundamental concept of sustainable development, this study empirically analyzes the spatio-temporal characteristics, formation mechanisms and obstacle factors of the urban-rural integration of shrinking cities in China, from 2008 to 2018. The conclusions are as follows: the overall level of the urban-rural integration of shrinking cities in China is low; the internal differences of urban-rural integration are also small, and the changes are slow. Next, the space difference is high in the east and low in the west, high in the south and low in the north. Moreover, differences exist among different levels of urban agglomerations. Urban economic efficiency, urban resources and environment, urban social equity and rural economic efficiency are the main factors affecting the urban-rural integration of shrinking cities in China. Urban and rural economic efficiency are the two most prominent shortcomings that restrict the urban-rural integration of shrinking cities. The spatial resistance mode of each city is more than the two-system resistance; the main resistance of shrinking cities with a higher level of urban-rural integration also comes from the non-economic field. This study expands the research scope that up till now has ignored the discussion of urban-rural issues in the research of shrinking cities at home and abroad, and provides practical guidance for the sustainable development of shrinking cities in China.

Sign in / Sign up

Export Citation Format

Share Document