Community composition of reef associated copepods in the lagoon of Davies Reef, Great Barrier Reef

Reef associated zooplankton were sampled at a fixed site in the north of the lagoon of Davies Reef in June, September and December 1989 and April 1990. Three sampling techniques were used to sample the zooplankton community on each occasion. Analysis of samples focussed on the copepod community. Triplicate vertical hauls of a 150 cm long, 50 cm diameter, 64 µm plankton net were made through the full water column and also for the top 6m only. Samples were taken over a 24 hour period (2 tidal cycles) at times corresponding to low tide, mid-tide (rising), high tide and mid-tide (falling). After each set of net hauls, Niskin casts were made at 3, 6 and 9 m depth and near the bottom. Subsamples of the water were filtered through a 35 µm filter for determination of the number of nauplii and additional subsamples were taken for chlorophyll analysis. Swarming copepod species, not well sampled using plankton nets, were observed using SCUBA and samples were collected and identified when swarms were abundant.In the laboratory, the preserved net samples were subsampled. Counts were made of adult copepods, identified to species and sex where possible, and juveniles identified to the lowest possible taxonomic level. This research was undertaken to describe diurnal, tidal and seasonal changes in the reef associated copepod community in the water column in the lagoon at Davies Reef.

1989年6月、9月、12月及1990年4月，研究人员于戴维斯礁（Davies Reef）潟湖北部的固定站位，采集了与珊瑚礁相关的浮游动物样本。每次采样均采用三种技术手段，本次样本分析的核心聚焦于桡足类（Copepoda）群落。研究使用网孔孔径64μm、长150cm、直径50cm的浮游生物网（plankton net），开展三次重复垂直拖网作业，分别覆盖全水柱及仅上层6米水深区域。采样周期覆盖24小时（包含2个潮汐周期），分别在低潮、涨潮中期、高潮及落潮中期四个时刻完成采样。每组网具拖网作业结束后，研究人员分别在3米、6米、9米水深及近底位置开展尼斯金采水器（Niskin）采样。取部分水样通过35μm滤膜过滤，以测定无节幼体（nauplii）的数量；另采集子样本用于叶绿素含量分析。对于浮游生物网难以高效采集的成群桡足类物种，研究人员借助水肺潜水（SCUBA）进行观测，并在集群丰度较高时采集样本完成物种鉴定。实验室阶段，研究人员对保存的网采样本进行分样处理：计数成年桡足类，尽可能鉴定至物种与性别水平，幼体则鉴定至尽可能低的分类阶元。本研究旨在描述戴维斯礁潟湖水柱内，与珊瑚礁相关的桡足类群落的昼夜、潮汐及季节变化特征。