WATER AND WASTEWATER QUALITY MONITORING, MCMURDO STATION, ANTARCTICA

McMurdo Station is the largest research station in Antarctica and has a population that ranges from 250 to 1200 people. Wastewater from the Station is macerated, was sometimes mixed with waste brine from the desalinization plant and is discharged to McMurdo Sound. Effluent water quality has been routinely monitored since 1989, and a special ambient water quality study was conducted by Idaho National Engineering Laboratory (INEL) personnel in 1992. Results of the effluent monitoring efforts show that low concentrations of a few organic contaminants have been detected, while concentrations of metals, particularly copper, are considerably higher. Ambient water quality and sea ice monitoring detected very few contaminants, all at very low levels. Only minor and variable dissolved oxygen depression was detected near the outfall. Diatom communities near the outfall differ in relative abundance, cell counts, and chlorophyll a content compared to control sites. For the purpose of evaluating the impact of McMurdo`s effluent on ambient water quality, improved effluent monitoring and sediment quality monitoring are recommended instead of frequent monitoring of ambient water quality.     

Organic contamination in the Great Wall bay,Antarctica in austral summer

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西南极南设得兰群岛纳尔逊岛冰雪的氢氧同位素组成

作者采集了西南极南设得兰群岛纳尔逊岛冰盖的冰雪样,并测得其δD和δO~(18)值分别为-67.8～-75.0‰和-8.72～-8.93‰,进而拟合出δD和δ~(18)O关系大致为δD=8δ~(18)O-1.5。本文从“大陆效应”、“温度效应”、“纬度效应”及降雪过程的同位素动力分馏等方面对所获资料作了讨论。     

菲尔德斯半岛火山构造及其时空演化

菲尔德斯半岛火山活动有两个高峰期,相应分为两个亚族回.火山机构有二类,一类以火山颈相岩柱为标志,另一类发育着火口相、近火口相集块岩、集块熔岩.据形成时间又可分为早期和晚期火山机构.火山活动明显受区域构造控制,为典型的裂隙中心式喷发,形成本区NW向、间距约为2km的火山喷发带.早期活动遍及全区,具有自SW向NE迁移的总体演化趋势;晚期沿火山喷发带自NW向SE局部性迁移.     

Peroxyacetyl nitrate (PAN) concentrations in the Antarctic troposphere measured during the photochemical experiment at Neumayer (PEAN'99)

Because investigations of PAN at higher southern latitudes are very scarce, we measured surface PAN concentrations for the first time in Antarctica. During the Photochemical Experiment at Neumayer (PEAN'99) campaign mean surface PAN mixing ratios of 13±7 pptv and maximum values of 48 pptv were found. When these PAN mixing ratios were compared to the sum of NO_x and inorganic nitrate they were found to be equal or higher. Low ambient air temperatures and low PAN concentrations caused a slow homogeneous PAN decomposition rate of approximately 5×10⁻² pptv h⁻¹. These slow decay rates were not sufficient to firmly establish the simultaneously observed NO_x concentrations. In addition, low concentration ratios of [HNO₃]/[NO_x] imply that the photochemical production of NO_x within the snow pack can influence surface NO_x mixing ratios in Antarctica. Alternate measurements of PAN mixing ratios at two different heights above the snow surface were performed to derive fluxes between the lower troposphere and the underlying snow pack using calculated friction velocities. Most of the concentration differences were below the precision of the measurements. Therefore, only an upper limit for the PAN flux of ±1×10¹³ molecules m⁻² s⁻¹ without a predominant direction can be estimated. However, PAN fluxes below this limit can still influence both the transfer of nitrogen compounds between atmosphere and ice, and the PAN budget in higher southern latitudes.     

高分辨气相色谱/高分辨质谱法测定南极样品中有机氯农药

建立了同位素稀释-高分辨气相色谱/高分辨质谱法(HRGC/HRMS)测定南极土壤、苔藓和地衣样品中23种有机氯农药的分析方法.样品经冷冻干燥、研磨处理后用正己烷∶二氯甲烷(1∶1,V∶V)混合溶剂进行加速溶剂萃取(ASE),萃取液经硅胶-氧化铝层析柱和C18小柱净化后,进HRGC/HRMS检测分析.样品中目标物定量采用平均相对响应因子法,6点标准曲线响应因子的相对标准偏差(RSD)≤20%,方法的线性范围为0.4—800μg·L-1,回收率在62%—101%之间.实际样品分析结果表明,23种OCPs的加标回收率为40%—100%,在土壤、苔藓和地衣样品中的检出限(LODs)分别为0.024—5.01、0.2—12.2、0.020—13.7 pg·g-1,可以满足南极环境样品中有机氯农药的检测分析.     

南极菲尔德斯半岛植被微区CO2浓度的监测

在南极苔藓植被的微环境区内,CO₂的浓度在473.5mg·m^-3以上,大大高于全球CO2的平均浓度(356 mg·m^-3),可见苔藓等植被区可能是大气CO₂的源之一.这与特殊的南极条件下植被的生理生态特性有关.在苔藓分布区,CO₂浓度日变化的主要影响因素是光照和温度.菲尔德斯半岛变化无常的天气状况使得CO₂浓度昼夜变化规律出现局部波动,不同的天气状况也使CO₂浓度发生变化.研究表明:光照条件是CO₂浓度变化的主导影响因素,从CO₂浓度的季节变化中可以看出,CO₂浓度变化与大气温度呈负相关;与降水量和空气相对湿度呈正相关.本文首次给出了极地环境下植被微区的CO₂浓度变化及其影响因素,为极地温室气体的研究提供了新的材料.     

太平洋上空硫酸盐的分布和来源

我国首次南极考察(1984年11月—1985年3月)在太平洋和南极半岛周围海域收集了31个海洋气溶胶样品。采用离子色谱法分析气溶胶中硫酸盐、火焰原子吸收法分析钠离子,结果表明,太平洋海洋气溶胶中非海盐源硫酸盐含量自北纬向南纬明显降低。在北太平洋主要是由于陆源污染源的硫酸盐在风系作用下经长距离传输而进入海洋上空;而在南太平洋,特别是南极半岛海域大气中非海盐源硫酸盐,可能主要来自海洋生物活动的产物。利用通量计算模式,估算了南极半岛海域生物源输入大气的硫通量为0.065gS/m~2·a。