Relationship between oxygen concentration,respiration and filtration rate in blue mussel Mytilus edulis

The large water-pumping and particle-capturing gills of the filter-feeding blue mussel Mytilus edulis are oversized for respiratory purposes. Consequently, the oxygen uptake rate of the mussel has been suggested to be rather insensitive to decreasing oxygen concentrations in the ambient water, since the diff usion rate of oxygen from water flowing through the mussel determines oxygen uptake. We tested this hypothesis by measuring the oxygen uptake in mussels exposed to various oxygen concentrations. These concentrations were established via N2-bubbling of the water in a respiration chamber with mussels fed algal cells to stimulate fully opening of the valves. It was found that mussels exposed to oxygen concentrations decreasing from 9 to 2 mg O_2/L resulted in a slow but significant reduction in the respiration rate, while the filtration rate remained high and constant. Thus, a decrease of oxygen concentration by 78% only resulted in a 25% decrease in respiration rate. However, at oxygen concentrations below 2 mg O_2/L M. edulis responded by gradually closing its valves, resulting in a rapid decrease of filtration rate, concurrent with a rapid reduction of respiration rate. These observations indicated that M.edulis is no longer able to maintain its normal aerobic metabolism at oxygen concentration below 2 mg O 2/L, and there seems to be an energy-saving mechanism in bivalve molluscs to strongly reduce their activity when exposed to low oxygen conditions.     

Spectroscopic and photometric studies of a candidate pulsating star in an eclipsing binary:V948 Her

Eclipsing binary stars with a pulsating component are powerful tools that allow us to probe the stellar interior structure and the evolutionary statuses with a good accuracy. Therefore, in this study,spectroscopic and photometric examinations of an eclipsing binary system V948 Her are presented. The primary component of the system is classified to be a candidate δ Scuti variable in the literature. The fundamental stellar, atmospheric and orbital parameters, and the surface abundance of the star were determined and the pulsation behaviour was investigated in this study. The orbital parameters were derived by the analysis of radial velocity and Super WASP light curves. The spectral classification was found to be F2V. The initial atmospheric parameters of the primary component were derived by analysis of the spectral energy distribution and hydrogen lines. The final atmospheric parameters and chemical abundances of the primary component were obtained by using the method of spectrum synthesis. As a result, the final atmospheric parameters were determined as T_(eff)= 7100±200 K, log g= 4.3±0.1 cgs and ξ = 2.2 ± 0.2 km s~(-1). The surface abundance was found to be similar to solar. The fundamental stellar parameters of both components were also obtained to be M = 1.722 ± 0.123, 0.762 ± 0.020 M⊙, R =1.655 ± 0.034, 0.689 ± 0.016 R⊙for primary and secondary components, respectively. The pulsation characteristic of the primary component was examined using Super WASP data and the pulsation period was found to be ~0.038 d. The position of the primary pulsating component was also obtained inside the instability strip of δ Sct stars. The primary component of V948 Her was defined to be a δ Sct variable.     

Defining a mountain landscape characterized by grazing using actor perception,governmental strategy,and environmental monitoring data

In multi-functional mountainous landscapes worldwide, conservation of natural values is a major task. Here, pro-active policies can be a way forward. National Environmental Quality Objectives(EQO) to solve environmental problems for future generations, however, often wrestle with being too visionary and lacking specificity, which complicates their implementation. The EQO "A Magnificent Mountain Landscape" that has been adopted by the Swedish Parliament in 1999 to preserve the pristine mountain environment in Sweden, experiences all these flaws. To aid its implementation, we studied the conditions and processes needed to define, to evaluate, and to preserve its goals across the Swedish mountain chain, using one of its milestone targets(a landscape characterized by grazing) as a study system. Applying qualitative and quantitative methods, we analyzed three types of data: 1) referral responses to the governmental strategy document, 2) interviews with relevant actors, and 3) environmental monitoring data(reindeer position data). Nationally,our results suggest a need for geographical differentiation to match regional/local conditions. Regionally, difference in both perception and definition of the milestone target among the actors hinders the formulation, monitoring, and evaluation of a common goal. Next to a culture-nature divide, we found that a "within as a user" and "from the outside as an observer" perspective influenced suggested definitions. Moreover, we found a need for better defining whether the goal is maintaining current conditions or restoring previous ones. Our result supports the use of animal position data as a decision support tool to monitor and to aid evaluation of the target. Given the number of actors involved and conflicts of interests present, we suggest the application of a structured decision process to accomplish agreements on a common goal. Here, environmental monitoring data can aid a "landscape assessment step" as a natural part in the decision process to target landscape management actions resourcefully and effectively.     

2022 年初冬伊犁河谷一次极端暴雪过程诊断分析

为了更全面地伊犁河谷极端暴雪发生发展的机制,利用常规探空和地面观测资料、FY-2H长波辐射资料(Outgoing Long-wave Radiation,OLR)和NCEP/NCAR１°×１°再分析资料,采用天气动力学分析方法对2022年11月22日-24日出现在伊犁河谷极端暴雪过程的成因和动力结构演变特征进行分析,结果表明:(1)此次降雪为强锋区降雪,锋区内不断有短波东移,是暴雪发生的大尺度环流背景；300hPa极锋急流、500hPa强锋区、700hPa强偏西急流的流场配置起至关重要作用。(2)低层冷空气入侵,迫使暖湿空气抬升、气温下降,形成了下冷上暖的强逆温层结,而导致降水相态转变。降雪持续时间长,导致强降雪发生。(3)低层偏西急流把水汽输送到暴雪区,并在暴雪区上方产生强的水汽辐合中心,为本次暴雪提供了有利的水汽条件。散度场对大暴雪的发生有较好的先兆意义,双辐合-辐散结构的散度场特征可以作为预报降雪加大的指标。(4)暴雪过程发生时大气处于对流稳定状态,但存在对称不稳定能量的释放。(5)OLR特征分析表明OLR３ｈ平均值与３ｈ降雪量存在明显的负相关关系。     

北疆北部一次暖区暴雪天气过程的的综合分析

利用地面观测、高空探测常规资料、NCEP 1°×1°再分析以及FY-2G红外云图资料，综合分析了2016年11月10—13日北疆北部的暖区暴雪过程成因，结果表明，此次暴雪天气是在“单阻型”经向环流和有利的高低空天气系统配置下发生的，主要表现为500 hPa东欧阻塞高压脊稳定，西西伯利亚低涡和冷槽东南下至北疆境外的中亚地区，200～500 hPa低涡和冷槽系统深厚且呈前倾结构，低涡底部极锋锋区加强并压至北疆上空，700～850 hPa北疆北部有暖平流和暖脊发展，地面气压场呈“两高夹一低”形势，北疆在地面冷锋前部和暖锋后部的暖区内。中高层西北急流、低层偏西气流和偏东气流三支气流在暴雪区上空汇合，暴雪区位于高空低涡底部西北急流、低层暖平流和切变线、地面暖低压南部的高低空重叠区域内。500 hPa以下仅有一条西方水汽输送路径，最强水汽输送在600～700 hPa，最强水汽辐合位于850 hPa附近，最大暴雪中心（裕民）的水汽输送强度更强、厚度更厚、时间更长，其平均云顶黑体亮温TBB值较富蕴偏高10℃左右。     

Probing Metals in Hydrothermal Ore Fluids: In-situ Experiments and Molecular Simulations

Please refer to the attachment(s) for more details.     

Linking bacterial and archaeal community dynamics to related hydrological,geochemical and environmental characteristics between surface water and groundwater in a karstic estuary

Subterranean estuaries(STEs) are characterized by the mixing of terrestrial fresh groundwater and seawater in coastal aquifers. Although microorganisms are important components of coastal groundwater ecosystems and play critical roles in biogeochemical transformations in STEs, limited information is available about how their community dynamics interact with hydrological, geochemical and environmental characteristics in STEs. Here,we studied bacterial and archaeal diversities and distributions wi...     

乌鲁木齐一次重污染过程及其边界层特征量分析

针对2020年1月5—17日乌鲁木齐出现的重污染天气，利用乌鲁木齐的探空站资料和地面常规气象数据计算了最大混合层高度、平均风速、逆温特性、边界层通风量、能见度、相对湿度等，对最大混合层高度、能见度、相对湿度与PM_2.5质量浓度进行了相关性分析，并利用Hysplit后向气团轨迹模式分析污染形成源。结果表明：此次重污染天气过程大气层结较为稳定，主要表现为逆温层厚(平均577 m)、逆温强度大(平均1.7℃/100 m)、最大混合层高度低(平均400 m)；边界层通风量对局地空气质量影响显著；PM_2.5质量浓度与相对湿度呈弱的正相关，与能见度呈指数相关；Hysplit后向气团轨迹模式分析得出此次污染过程以局地排放为主要形成源。