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，对礁栖浮游动物（reef-associated zooplankton）开展采样工作。每次采样均采用三种技术对浮游动物群落进行采集，样本分析核心聚焦于桡足类（copepod）群落。研究使用长150 cm、直径50 cm、网孔孔径64 µm的浮游生物网（plankton net），分别在全水柱及表层6米水深范围内完成三次重复垂直拖网采样；采样时段覆盖24小时（含2个潮汐周期），分别对应低潮（low tide）、涨潮中期（mid-tide (rising)）、高潮（high tide）及落潮中期（mid-tide (falling)）四个时刻。每完成一组网具拖采后，研究人员在3 m、6 m、9 m水深及近底位置开展尼斯金采水器（Niskin sampler）采样。采集的海水子样本经35 µm滤膜过滤后，用于计数无节幼体（nauplii）数量；同时额外采集子样本用于叶绿素分析（chlorophyll analysis）。针对浮游生物网采样效果欠佳的群集性桡足类物种，研究人员通过水肺潜水（SCUBA）开展观测，并在群集丰度较高时采集样本进行物种鉴定。实验室环节中，研究人员对保存的网采样本进行分样：对成年桡足类开展计数，在条件允许时鉴定至物种及性别水平；幼体则鉴定至尽可能低的分类学层级（taxonomic level）。

本研究旨在阐明戴维斯礁潟湖内水柱中礁栖桡足类群落的昼夜、潮汐及季节变化规律。