The effects of cyclone Winifred and bioturbation on sediments and sediment fauna of coral reef lagoons on the Great Barrier Reef

Tropical cyclone Winifred (Category 3) crossed the Great Barrier Reef north of Townsville on the 1st February 1986. Sediment samples were collected from the lagoons of reefs close to the track of cyclone Winifred and at reefs at a range of distances from the cyclone track.Three reefs in the path of the cyclone (Gilby Reef, Feather Reef and Potter Reef) were sampled within six days of the cyclone. Potter Reef had been sampled for another project prior to the cyclone and was sampled a third time 6 weeks after the cyclone. Rib Reef, the most distant of the reefs from the track of the cyclone had been sampled prior to the cyclone and was sampled again 14 days and 6 weeks after the cyclone. Noggin Reef and Otter Reef were sampled only once, 6 weeks after the cyclone.Observations on topography, sediment type and surface detritus of the lagoon sediments of each reef were made at 15 second intervals from a manta board towed at 2 knots. Sediment samples were collected for faunal analysis using a corer with a internal diameter of 5.5 cm. Cores were collected at a representative site within each reef lagoon at a depth of about 10m. Four groups of five, 20 cm long cores were collected at each site. Groups of cores were collected within an area of 1m² and groups were separated by approximately 4 m.Three surface sediments samples were collected from each reef lagoon for organic carbon and organic nitrogen analyses and analysis of grain size distribution.
This research was undertaken to determine whether:1. cyclones impact on the sediment and sediment fauna of reef lagoons2. the impacts of cyclones on the sediment and sediment fauna are long lasting

1986年2月1日，三级（Category 3）热带气旋温妮弗雷德（Winifred）穿过汤斯维尔（Townsville）以北的大堡礁（Great Barrier Reef）。研究人员从靠近温妮弗雷德气旋路径的珊瑚礁潟湖，以及距离气旋路径不同距离的珊瑚礁中采集了沉积物样本。气旋路径上的三座珊瑚礁（Gilby Reef、Feather Reef、Potter Reef）在气旋过后六天内完成采样。波特礁（Potter Reef）此前因另一项研究已在气旋前完成采样，气旋过后六周又进行了第三次采样。里布礁（Rib Reef）是距离气旋路径最远的珊瑚礁，其在气旋前已完成采样，并在气旋过后14天及6周分别进行了再次采样。诺金礁（Noggin Reef）和水獭礁（Otter Reef）仅在气旋过后六周进行过一次采样。研究人员通过以2节航速拖曳的蝠鲼板（manta board），以15秒为间隔对各珊瑚礁潟湖沉积物的地形、沉积物类型及表层碎屑进行观测。用于动物群分析的沉积物样本通过内径5.5厘米的岩心取样器（corer）采集。每个珊瑚礁潟湖内具有代表性的位点（水深约10米）采集了四组样本，每组包含5根长度为20厘米的岩心。每组岩心采集于1平方米范围内，组间间距约4米。每个珊瑚礁潟湖采集3份表层沉积物样本，用于有机碳、有机氮含量分析及粒度分布分析。本研究旨在探究以下问题：1. 气旋是否会对珊瑚礁潟湖的沉积物及底栖动物群产生影响；2. 气旋对沉积物及底栖动物群的影响是否具有持久性。