Diatom, and associated data from grid samples collected in Brown Bay

Sediment samples were collected from nine points along 3 parallel transects within the contaminated Brown Bay. The diatom spreadsheet (diatom_data) contains both initial diatom counts and the relative abundance of benthic species. The abbreviation used to identify species are explained in the separate file called sp_list. Metal, Total Purgeable Hydrocarbons (TPH), and grain-size data are all presented as separate files.This work was completed as part of ASAC project 1130 (ASAC_1130) and project 2201 (ASAC_2201).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.Public summary from project 2201:As a signatory to the Protocol on Environmental Protection to the Antarctic Treaty Australia is committed to comprehensive protection of the Antarctic environment. This protocol requires that activities in the Antarctic shall be planned and conducted on the basis of information sufficient to make prior assessments of, and informed judgements about, their possible impacts on the Antarctic environment. Most of our activities in the Antarctic occur along the narrow fringe of ice-free rock adjacent to the sea and many of our activities have the potential to cause environmental harm to marine life. The Antarctic seas support the most complex and biologically diverse plant and animal communities of the region. However, very little is known about them and there is certainly not sufficient known to make informed judgements about possible environmental impactsThe animals and plants of the sea-bed are widely accepted as being the most appropriate part of the marine ecosystem for indicating disturbance caused by local sources. Attached sea-bed organisms have a fixed spatial relationship with a given place so they must either endure conditions or die. Once lost from a site recolonisation takes some time, as a consequence the structure of sea-bed communities reflect not only present conditions but they can also integrate conditions in the past. In contrast, fish and planktonic organisms can move freely so their site of capture does not indicate a long residence time at that location. Because sea-bed communities are particularly diverse they contain species with widely differing life strategies, as a result different species can have very different levels of tolerance to stress; this leads to a range of subtle changes in community structure as a response to gradually increasing disturbance, rather than an all or nothing response.This project will examine sea-bed communities near our stations to determine how seriously they are affected by human activities. This information will be used to set priorities for improving operational procedures to reduce the risk of further environmental damage.The fields in this dataset are:bbg_lat spreadsheetSiteLatitudeLongitudeEastingNorthingDiatoms spreadsheetSpeciesSiteAbundanceTransectMetals SpreadsheetSampleAntimonyArsenicCadmiumChromiumCopperIronLeadManganeseMercuryNickelSilverTinZincTotal Organic CarbonEastingNorthingTPH SpreadsheetSiteTotal Purgeable HydrocarbonsFraction of Purgeable Hydrocarbons

沉积物样本采自受污染的布朗湾（Brown Bay）内3条平行测线沿线的9个采样点位。硅藻数据表（diatom_data）包含初始硅藻计数及底栖物种相对丰度数据，物种识别所用的缩写释义详见独立文件sp_list。金属、总可吹扫烃类（Total Purgeable Hydrocarbons, TPH）及沉积物粒度数据均以独立文件形式提供。

本项研究由ASAC项目1130（ASAC_1130）与项目2201（ASAC_2201）资助完成。

### 项目1130公开摘要
藻垫广泛分布于多数浅海海底环境中，据估算其在多数区域的总初级生产力占比超过一半，是无脊椎动物与部分鱼类的关键食物来源。本项目将明确藻垫在南极海洋环境中的生态重要性，并解析当地排污与倾废点污染对其造成的影响；同时还将探究臭氧空洞引发的额外紫外辐射对藻垫的生态效应。

### 项目2201公开摘要
作为《南极条约环境保护议定书》缔约方，澳大利亚致力于全面保护南极环境。该议定书要求，南极地区的所有活动均需基于充足信息开展规划与实施，以便对其可能给南极环境带来的影响进行预先评估与审慎判断。澳大利亚在南极的多数科考活动均集中于毗邻海洋的狭长无冰岩带区域，且诸多活动存在对海洋生物造成环境损害的潜在风险。

南极海域孕育了该区域最为复杂、生物多样性最丰富的动植物群落，但目前对这些群落的了解极为有限，尚不足以对潜在环境影响作出审慎判断。海底动植物被广泛认为是海洋生态系统中最适宜用于指示本地源干扰的组成部分：附着型海底生物与特定区域存在固定的空间关联，因此它们要么耐受当地环境条件，要么死亡。一旦某区域的附着生物消失，其重新定殖需要耗费较长时间，因此海底群落结构不仅能反映当前环境状况，还可整合记录历史时期的环境条件。与之相反，鱼类与浮游生物可自由移动，因此其捕获位点无法反映它们在该区域的长期停留情况。

由于海底群落具有极高的多样性，其中包含生活策略差异极大的物种，因此不同物种对胁迫的耐受水平存在显著差异；这使得群落结构会随干扰程度的逐步增加出现一系列细微变化，而非全有或全无的响应模式。本项目将对科考站附近的海底群落开展调查，以明确其受人类活动影响的严重程度，相关调查结果将用于制定优化作业流程的优先级，以降低进一步造成环境损害的风险。

本数据集包含以下数据表及对应字段：
1. bbg_lat 数据表：采样点、纬度、经度、东向坐标、北向坐标
2. 硅藻数据表：物种、采样点、丰度、断面编号
3. 金属数据表：采样样品、锑、砷、镉、铬、铜、铁、铅、锰、汞、镍、银、锡、锌含量及总有机碳
4. 坐标字段：东向坐标、北向坐标
5. 总可吹扫烃类（TPH）数据表：采样点、总可吹扫烃类含量、可吹扫烃类组分占比