Interseasonal variability of benthic diatoms communities within the Windmill Islands, Antarctica

Sediment samples were collected with an Eckamn grab from four locations within the Windmill Islands (Herring Island, O'Connor Island, Shannon Bay and Brown Bay). A weekly sampling program was performed over a 10 week period, however not all locations could be accessed each time due to sea-ice conditions. All samples were collected at an 8 m water depth. Preliminary analysis of fortnightly samples are presented here. Diatom data are given as relative abundances of benthic diatom species. The abbreviations used to identify species are explained in the accompanying file sp_list.

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 impacts.

The 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:

Species
Site
Abundance
Benthic
Date
Location

研究人员使用埃克曼采泥器（Eckamn grab）从风车群岛（Windmill Islands）内的四个地点（鲱鱼岛Herring Island、奥康纳岛O'Connor Island、香农湾Shannon Bay和布朗湾Brown Bay）采集沉积物样本。采样计划为期10周，每周进行一次，但受海冰状况影响，并非每次都能到达所有地点。所有样本均在8米水深处采集。本文呈现的是每两周一次样本的初步分析结果。硅藻数据以底栖硅藻物种的相对丰度表示，物种识别所用的缩写在附带文件sp_list中说明。

本研究为澳大利亚南极科学咨询委员会（ASAC）项目1130（ASAC_1130）和项目2201（ASAC_2201）的部分成果。

ASAC项目1130公开摘要：
藻垫（algal mats）广泛分布于多数浅海环境的海底，被认为贡献了这些区域超半数的总初级生产力，是无脊椎动物和部分鱼类的关键食物来源。本项目旨在明确藻垫在南极海洋环境中的重要性，测定当地污水及垃圾场污染对其的影响，并探究臭氧空洞导致的额外紫外线辐射对藻垫的作用。

ASAC项目2201公开摘要：
作为《南极条约环境保护议定书》（Protocol on Environmental Protection to the Antarctic Treaty）的签署国，澳大利亚承诺全面保护南极环境。该议定书要求，南极地区的活动需基于充足信息进行规划与实施，以预先评估并就其对南极环境的潜在影响作出知情判断（informed judgements）。澳大利亚在南极的多数活动集中于临海的狭窄无冰岩石带，其中多项活动可能对海洋生物造成环境危害。南极海域支撑着该区域最复杂且生物多样性最丰富的动植物群落，然而目前对其了解甚少，远不足以就潜在环境影响作出知情判断。

海底动植物被广泛认为是指示本地污染源所致扰动的最适宜海洋生态系统组分。固着型海底生物与特定地点存在固定空间关系，因此必须耐受环境条件或死亡。一旦从某地点消失，重新定殖需耗费一定时间，故海底群落结构不仅反映当前环境条件，还能整合历史条件。相比之下，鱼类和浮游生物可自由移动，其捕获地点无法表明在该区域的长期停留时间。由于海底群落多样性极高，包含具有不同生活策略的物种，不同物种的压力耐受度差异显著；这导致群落结构对逐渐增强的扰动产生一系列细微变化，而非全有或全无的反应。

本项目将调查考察站附近的海底群落，以确定其受人类活动影响的严重程度。所得信息将用于设定优先级改进操作流程，降低进一步环境损害的风险。

本数据集包含以下字段：物种（Species）、采样点（Site）、丰度（Abundance）、底栖性（Benthic）、日期（Date）、位置（Location）