氨氮和亚硝酸盐对斜带石斑鱼苗的急性毒性效应

研究了水温(25±0.5)℃,盐度30~31,pH值7.9~8.1,溶解氧4.5~5.5 mg/L条件下氨氮和亚硝酸盐对不同规格斜带石斑鱼(Epinephelus coioides)苗的急性毒性效应。试验结果表明,氨氮对平均全长4.4cm的斜带石斑鱼苗的24、48、72、96 h LC50及安全质量浓度分别为5.62、3.50、2.93、2.68及0.27 mg/L,对应的非离子氨及安全质量浓度分别为0.23、0.14、0.12、0.11及0.011 mg/L;氨氮对平均全长10.5 cm斜带石斑鱼苗的24、48、72、96 h LC50及安全质量浓度分别为58.6、56.2、53.3、51.4及5.13 mg/L,对应的非离子氨及安全质量浓度分别为2.41、2.32、2.20、2.12及0.21 mg/L;亚硝酸盐对全长4.4 cm的斜带石斑鱼苗的24、48、72、96 h LC50及安全质量浓度分别为288.4、281.8、270.4、267.3及26.7 mg/L;亚硝酸盐对全长10.5 cm的斜带石斑鱼苗的24、48、72、96 h LC50及安全质量浓度分别为354.8、346.7、280.5、208.4及20.8 mg/L。     

缢蛏(Sinonovacula constricta)GST和HSP90基因克隆及其在氨氮胁迫下的表达特征分析

克隆获得缢蛏(Sinonovacula constricta)谷胱甘肽S-转移酶(Sc-GSTσ)和热休克蛋白90(ScHSP90)基因的cDNA全长,分析了它们的组织表达差异及其在氨氮胁迫下的表达特征。结果表明,Sc-GSTσ的全长cDNA为1 414 bp,含有639 bp的开放阅读框(Open Reading Frame,ORF),编码212个氨基酸,Sc-GSTσ氨基酸序列与其他物种的GST氨基酸序列同源性为31.88%～43.40%;而Sc-HSP90的全长cDNA为2 752 bp,ORF为2 181 bp,编码726个氨基酸,其氨基酸序列与其他物种HSP90的氨基酸序列同源性为76.77%～87.05%。荧光定量PCR分析发现,Sc-GSTσ和Sc-HSP90在缢蛏各组织中均有表达,两者均在肝胰腺中表达量最高。氨氮胁迫后,Sc-GSTσ和Sc-HSP90 mRNA在肝胰腺中表达均显著上调(p<0.05),表明氨氮胁迫引起机体的应激反应,2个基因可能参与机体解毒或防御过程。但胁迫后期表达量下降推测是机体的防御能力有限,不足以完全保护宿主免受应激诱导的细胞损伤。     

Optimization of the indophenol blue method for the automated determination of ammonia in estuarine waters

Existing automated methods for the determination of ammonia in natural waters suffer from serious ‘salt error’ in estuaries because of changes in pH, ionic strength and optical properties with salinity. A modified automated indophenol blue method is described which minimizes the ‘salt error’ to less than 8% over the entire salinity of estuaries.     

Effects of Temperature and Salinity on Oxygen Consumption and Ammonium Excretion Rate of ♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus Juveniles

The impact of water temperature(24, 27, 30 and 33℃) and salinity(15, 20, 25, 30 and 33) on oxygen consumption(OCR) and ammonium excretion rate(AER) of ♀ Epinephelus fuscoguttatus ×♂ E. lanceolatus hybrid grouper juveniles(9.39 ± 0.07 g) were investigated under the fed and un-fed conditions. The results showed that the OCR and AER were significantly(P < 0.05) affected by temperature and salinity under both fed and un-fed conditions. When temperature was 24–33℃, the OCR and AER of fed hybrid grouper juveniles were 85.68%–129.52% and 125.78%–287.63%, respectively, higher than those of un-fed hybrid grouper juveniles. The O/N ratio, protein use(P_u), Q₁₀(respiration) and Q₁₀(excretion) of fed hybrid grouper juveniles were 14.43–24.01, 28.35% – 48.48%, 1.69 and 3.01, respectively. The O/N ratio, P_u, Q₁₀(respiration), Q₁₀(excretion) of un-fed hybrid grouper juveniles were 20.39 – 31.79, 22.16% – 34.34%, 1.23 and 1.17, respectively. When salinity was 15–33, the OCR and AER of fed hybrid grouper juveniles increased by 87.42% – 116.85% and 215.38% – 353.57%, respectively, over those of un-fed hybrid grouper juveniles. The O/N ratio and P_u of fed hybrid grouper juveniles were 14.48 – 17.78, 39.36% – 49.43%, respectively. The O/N ratio and Pu of un-fed hybrid grouper juveniles were 20.39 – 31.79 and 22.16% – 34.34%, respectively. The specific dynamic action(SDA) of hybrid grouper juveniles was mainly related to protein metabolism. The results had a guiding significance to the large-scale intensive aquaculture of hybrid grouper juveniles.     

污染河水中氨氮对浅层地下水的影响

氨氮是目前地表水和地下水的一个重要污染源.室内试验选用3种天然砂土作为渗透介质, 以生活污水模拟污染河水, 经过近1 0个月的土柱试验, 发现氨氮在粗砂中第1 7天达吸附饱和, 第1 8— 1 4 0天去除率小于1 0 %, 在中砂中第1 30—1 4 0天吸附饱和, 以后均发生解吸出水浓度大于进水浓度.野外实验凉水河的氨氮浓度为4 6.86mg/L和2 6.95mg/L时, 地下水的氨氮浓度均小于1.1 0mg/L, 表明凉水河对地下水的实际影响不如室内大, 原因是底泥、河床下部渗透介质的厚度和岩性以及河水渗漏量的影响.排污河还清试验表明, 排污河清淤、灌入清水后, 会很明显地把排污河下部渗透介质中的氨氮带到地下水中, 造成地下水的二次污染.      

Sediment quality of the lower St. Johns River, Florida: an integrative assessment of benthic fauna, sediment-associated stressors, and general habitat characteristics

Sediment quality of the lower St. Johns River (LSJR) estuary, Florida was evaluated using synoptic data on benthic community structure, levels of potential stressors (chemical contaminants, ammonia and sulfide), and other basic habitat characteristics (depth, dissolved oxygen, salinity, temperature) collected at seven stations, three times a year from July 2000-July 2002. Un-ionized ammonia and hydrogen sulfide were detected at toxic levels on at least one sampling occasion at four stations. Chemical contamination of sediment at probable bioeffect levels also was observed at four stations. Concentrations of pesticides or other chemical substances typically associated with human activities (e.g., PCBs) were detectable at all stations, though not always present at concentrations likely of causing significant bioeffects. A total of 251 taxa and 9783 individuals were identified and enumerated from the benthic infaunal samples. Polychaete worms and molluscs dominated the benthic fauna at all seven stations. The opportunistic and pollution-tolerant polychaete Streblospio benedicti was the most abundant species overall (from all samples combined), appearing as a dominant at five of the seven stations. Overall, the sites sampled as part of this study indicate a highly stressed benthos resulting from multiple anthropogenic impacts.     

天然海水硝酸盐氮同位素组成的蒸馏法测定

建立了测定天然海水中硝酸盐氮同位素组成的蒸馏法,该方法主要是在碱性条件下利用戴氏合金将海水中的硝酸盐还原为氨,后利用稀盐酸吸收生产的氨,将得到的氨吸收液浓缩后干燥结晶,利用同位素比值质谱仪测定所得晶体的氮同位素组成。研究中开展了戴氏合金添加量及氨吸收溶液在不同条件下干燥结晶对氮同位素测值的影响研究。结果表明,戴氏合金添加量为3.0 g及60 ℃下直接干燥结晶为最佳的实验条件。所建立的氨蒸馏法氮空白值仅为(0.90±0.19) μmol,低于此前文献报道的氮空白值;氮同位素组成(δ15N)空白值为(-14.7±4.1)×10-3。运用所建立的氨蒸馏法实测得到的硝酸盐δ15N值与氨扩散法、硝酸盐直接测定法得到的数值非常吻合,进一步证明所建立氨蒸馏法的可靠性。改进后的氨蒸馏法适用于硝酸盐浓度在2~50 μmol/dm3内的天然海水硝酸盐氮同位素组成的测定,方法的标准偏差为±0.3×10-3。     

光纤光化学氨传感器的研究及应用

氨是导致海洋水体富营养化的重要因素之一，基于光纤光化学检测的氨传感器特别适于氨的原位或在线分析。文章介绍了光纤光化学氨传感器的基本原理，光纤敏感膜的制备方法及其一些应用管况。发展小型、实用的光纤光化学传感器是未来海水中氨的原位、在线检测的发展趋势之一。     

Statistical analysis of estuarine profiles: II application to arsenic in the Tamar estuary (S.W. England)

By combining field observations with a statistical approach and a simple but effective estuarine analogue, the main features of the cycling of arsenic in the Tamar estuary have been elucidated. As(III) and As(V) enrichment in the water column is due to a combination of localized inputs and effective recycling of sediment interstitial waters. The profiles of As(V) are similar to those of NH₄⁺ and are dominated by an estuarine maximum resulting from an input from the sediments. As(III) profiles are correlated with those of dissolved manganese and exhibit both fresh water and estuarine maxima. As(III) appears to be effectively removed at the freshwater/brackish water interface by a combination of heterogenous oxidation, catalysed by hydrous manganese dioxide, and adsorption on to iron oxyhydroxide. The estuarine distribution of As(III) within the water column is consistent with the published rates of oxidation of As(III) to As(V) by both inorganic and microbiological processes. The reduction of As(V) to As(III) in the sediments is incomplete. On the basis of our observations a tentative estuarine arsenic cycle is presented.     

日本囊对虾(Marsupenaeus japonicus)秋繁仔虾形态表型对氨氮耐受性能的影响效应

以体长7.643±0.639mm的日本囊对虾秋繁同生群仔虾为实验对象,以氨氮为胁迫因子,在水温18.0±1.0oC、盐度20、p H 8.1±0.2的条件下,经确认其96h成活率略低于5%的氨氮攻毒质量浓度为52.37mg/L后,以此为氨氮急性攻毒实验质量浓度,借助显微扫描像素测量技术和多元分析方法定量研究了A、B、C、D、E实验群体(依次为氨氮攻毒0—24h、24—48h、48—72h、72—96 h时段内的死亡群体和氨氮攻毒96 h时的存活群体)间形态表型特征的差异。结果表明:(1)在所涉15项形态性状中,各实验群体间均无显著差异(P0.05)的性状仅为总长和第四腹节长;(2)在所涉17项形态比例指标中,各实验群体间均无显著差异(P0.05)的指标共计3项,依次为第五腹节长/总长、额剑长/头胸甲长和尾节高/尾节长,各实验群体间的欧氏距离均达到显著水平(P0.01),且均有随耐氨氮性能差异的增大而呈显著增大的趋势;(3)经主成分分析,提取到的5个特征值均大于1的主成分,累计贡献率达85.940%,其中第1主成分的贡献率高达46.121%,其载荷绝对值大于0.5的主要影响变量占形态比例指标总数的64.706%;(4)将氨氮急性攻毒处理所获E实验群体定义为选留群,其余实验群体统归为淘汰群,经判别分析,所建的Fisher分类函数方程组可较清晰地区分淘汰群和选留群个体,其中选留群和淘汰群个体的判别准确率P1分别为99%和86.75%,P2分别为88.20%和98.86%,两者综合判别准确率为92.88%。