南极沿海伯尔顿盐湖双刺镰状水蚤种群生态及其与盐湖环境的关系

对南极沿海伯尔顿盐湖浮游桡足类双刺镰状水蚤(Drepanopus bispinosus)种群生态进行了全年连续观察和研究,结果表明,该水蚤为一年一代,其个体发育周期,雄性约为10～12个月,雌性约为12～18个月。种群密度随季节不同而差异较大,其成体高密度期约在6～9月份,幼体高密度期大约在11～12月份,主要为无节幼体,桡足幼体Ⅰ期的高密度期出现在1月份。该水蚤繁殖期大约从6月至翌年1月,期间出现两次生殖高峰,7～8月为前一高峰期,所出现的无节幼体受环境因子主要是湖中食物和含氧量不足的影响而不能继续发育至桡足幼体Ⅰ期以上的阶段,后一高峰大约在10～12月,所出期的无节幼体能继续发育至桡足幼体各期直至成体。伯尔顿湖双刺镰状水蚤种群生态特征及其出现两次生殖高峰的现象,可能与该湖环境的季节变化有关。

THE ECOLOGY OF DREPANOPUS BISPINOSUS (GOPEPODA: CALANOIDA) AND THE EFFECTS OF ENVIRONMENTAL FACTORS ON IT IN A MEROMICTIG LAGOON, ANTARCTICA

The ecology of D bispinosus (Copepoda: Calanoida) was studied through the year of December 1983-January 1985. The animal had one generation for one year. Their individual life cycle of male could be in 10-12 months, and female could be in 12-18 months. The population density had marked seasonal variations. The higher density of adult appeared in June- September, and higher density of larva (mainly are nauplii) appeared in November and higher copepodites in January. Reproductive activities of animal went through from June to next January. There were two reproductive peaks in this period. The first peak arised in July to August. Although, a few of stage I copepodite would be found in the lake, mostly the nauplii presented in this peak time would not be able to grow into copepodites by restraining factors, such as food lack and low dissolved oxygen. The second peak arised about in October-December. Many of nauplii presented in these months could develop to copepodites and further to adults. The ecological characteristics of population as above, are related with seasonal changes of the environmental condition of the meromictic lake. The copepods were in progress of life activities following seasonal conditions of the lake, for obtaining best existence. They mated and laid eggs in winter to spring, in which it was more stability in temperature and salinity in the lake. And numbers of larva presented and grew in summer to autumn, being in conditions of abundant food and rich dissolved oxygen.