Diatom data for transects at 4 locations in the Windmill Islands

Sediment samples were collected from four locations within the Windmill Islands (Cloyd Island, Odbert Island, Shannon Bay and Brown Bay). Within each location three parallel transects were created, with samples taken at set depths along each transect. At the time of collection, both surface and benthic irradiance levels were measured, and the % of surface irradiance that reached the sediment-water interface was calculated. Samples were analysed for benthic diatom abundances (expressed as relative abundances), and grain-size (expressed as % of total weight).The diatom spreadsheet (diatom_data)lists the relative abundance of benthic species. The abbreviation used to identify species are explained in the separate file called sp_list. Samples are identified XTYZ where X is the first letter of the location, Y indicates the sampling position along the transect and z indicates the transect (a, b or c). The benthic sheet is the relative abundances of benthic species. The greater than 2% sheet lists all the species that reach abundances greater than2% in at least 1 sample. The table sheet has the same info as greater than 2% but arranged by the individual locations. In this sheet (tables), measurements in m represent the depth of the water column overlying the position where the sediment samples were collected. (ie it was at different locations, not different water depths in the one spot).Sampling positions reflect increasing depth. At Brown Bay and Odbert Island, sediment samples were collected below water columns/water depths of 1, 2, 4, 8 and 12 m. At Cloyd Island, samples were collected from 4,6,8 and 12 m water depths. At Shannon Bay samples were collected from 2, 4, 8, and 12 m water depths.Details of the environmental parameters examined (grainsize and light) are given in the file labelled 'env_data'This work was completed as part of ASAC project 1130 (ASAC_1130).Public summary from project 1130:Algal mats grow on sea floor in most shallow marine environments. They are thought to contribute more than half of the total primary production in many of these areas, making them a critical food source for invertebrates and some fish. We will establish how important they are in Antarctic marine environments and determine the effects of local sewerage and tip site pollution. We will also investigate the impact on the algal mats of the additional UV radiation which results from the ozone hole.The fields in this dataset are:Diatom SpreadsheetSpeciesSiteLocationTransectDepth (m)Environmental Data SpreadsheetLocationTransectDepth (m)Grain sizeGravelSandMudLight

本研究的沉积物样品采集自风车群岛（Windmill Islands）内的4处采样站位，分别为克洛依岛（Cloyd Island）、奥伯特岛（Odbert Island）、香农湾（Shannon Bay）与布朗湾（Brown Bay）。每个采样站位均设置3条平行样带，沿每条样带按预设深度采集沉积物样品。采样期间同步测定表层海水与底栖辐照度，并计算抵达沉积物-水界面的表层辐照度占比。

对所有样品开展两项分析：一是底栖硅藻（benthic diatom）丰度（以相对丰度表示），二是沉积物粒度（以各组分占总样品重量的百分比表示）。硅藻数据表（diatom_data）收录了底栖物种的相对丰度数据，物种标识所用的缩写代码的详细说明，详见独立文件sp_list。

样品命名规则为XTYZ格式：其中X为对应采样地点名称的首字母，Y代表样带上的采样位置序号，z代表样带编号（a、b或c）。“底栖生物”工作表存储底栖物种的相对丰度数据；“丰度>2%”工作表汇总了至少在1个样品中丰度超过2%的所有物种。“汇总表”工作表与“丰度>2%”工作表内容一致，但按单个采样站位进行整理排布。本工作表（tables）中以米为单位的数值，代表沉积物采样点上方的水柱水深——即该水深数值对应不同采样站位，而非同一点位的不同水深梯度。采样站位的排布遵循水深递增的梯度。

布朗湾与奥伯特岛的沉积物样品采集自水深1、2、4、8、12 m的站位；克洛依岛的采样站位水深为4、6、8、12 m；香农湾的采样站位水深为2、4、8、12 m。本次分析涉及的环境参数（沉积物粒度与光照）的详细数据，详见文件env_data。

本研究为ASAC 1130项目（ASAC_1130）的研究内容之一。项目1130的公开研究概要如下：藻垫（algal mats）广泛定植于多数浅海海底生境，据测算其贡献了上述生境总初级生产力的一半以上，是无脊椎动物与部分鱼类的关键食物来源。本研究旨在明确藻垫在南极海洋生境中的重要性，评估当地生活污水与垃圾填埋场污染对其造成的影响，同时探究臭氧空洞引发的额外紫外辐射对藻垫的干扰效应。

本数据集包含以下字段：
硅藻数据表
物种
采样站位
地点
样带
水深（m）
环境数据表
地点
样带
水深（m）
粒度
砾石
砂
泥
光照