Planktonic protist communities in semi-enclosed mariculture waters: temporal dynamics of functional groups and their responses to environmental conditions

The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao,Shandong Province,China,during a six-month study period (a complete shrimp-culture cycle) from May to October 2002.The results reveal that: (1) the protist communities represented five trophic and functional groups of the species identified,about 60% were photoautotrophs,20% algivores,12% bacterivores,5% raptors and about 3% non-selectives;(2) the photoautotrophs,algivores and bacterivores were the primary contributors to the changes in the protist communities in short temporal scales,the succession of dominance typically being bacterivores→photoautotrophs→algivores,with the raptors dominating the protist communities in a single sample (early June);(3) the photoautotrophs and non-selectives were the primary contributors to the peak of protist abundance in early October whereas the photoautotrophs,bacterivores,raptors and non-selectives mainly gave rise to two bimodal peaks of biomass in July and October respectively;(4) five functional groups of protist communities represented significant correlations with water nutrients (i.e.,NH 3-N,NO 3-N,and PO 4 ),either alone or in combination with temperature,of which algivores and raptors were strongly correlated with phosphate and the concentration of Chl a,while bacterivores were strongly related to nitrogen and the concentration of bacteria.These findings confirm that planktonic protists are potentially useful bioindicators of water quality in the semi-enclosed mariculture system.     

成都市6座湿地公园中昆虫群落的结构与多样性

2020年5月至9月,采用随机取样和系统取样相结合的方法,对成都市的白鹤滩国家湿地公园、白鹭湾湿地公园、香城湿地生态公园、青龙湖湿地公园和南湖湿地公园中的昆虫群落组成、结构和生物多样性进行了调查和分析。研究结果表明,在6座湿地公园中,共采集昆虫样本9993号,记录了16目141科486种昆虫,半翅目、鞘翅目、鳞翅目、双翅目、蜻蜓目、直翅目和膜翅目昆虫为优势类群;桤木河湿地公园和白鹤滩国家湿地公园中昆虫群落的多样性水平较高,昆虫群落结构复杂;在6座湿地公园中,植食性昆虫的科、物种和个体数量都远大于捕食性昆虫、中性昆虫、寄生性昆虫;只有少数湿地公园中的植食性昆虫与捕食性昆虫的个体数量之间、植食性昆虫与寄生性昆虫物种数量之间和个体数量之间存在显著的正相关关系。     

抑制型电导-离子色谱法测定地下水中碘化物

在无外来碘食物的环境下,水中碘含量是衡量人体碘摄入量的重要指标,因此准确测定饮用水中碘化物的含量对人类健康有着至关重要的作用。具有烷醇基季铵功能团的IonPac AS23色谱柱,具有较强亲水性,可在很宽的pH范围内(0～14)保持高容量,适于氢氧根淋洗液体系和碳酸根淋洗液体系,基于此,本文建立了一种抑制型电导-离子色谱法检测地下水中碘化物的方法。采用IonPac AS23型阴离子分析柱和IonPac AS23阴离子保护柱,50mmol/L的KOH淋洗液,其流速为1.2mL/min,抑制型电导检测器电流为125mA,对地下水中碘化物进行检测。该方法在8.980min出峰,方法检测限为0.5μg/L,方法标准曲线的相关性r=0.9998,线性范围较广(0.01～2mg/L)。该方法检测限更低、出峰时间更短,且不受水中7种无机阴离子的测定干扰,提高了氢氧根淋洗液体系下,烷醇基季铵功能团色谱柱AS23测定地下水中碘化物的准确度。