Data from a 3 m sediment core collected west of Pidgeon Island in the Windmill Islands, Antarctica

A sediment core was collected from the western side of Pidgeon Island, (66.3216 S, 110.445 E) at a water depth of 82.0 m. This sediment core (PG 1411-2) was recovered using a release-controlled piston corer, with a length of 3 m, using the coring technique described in Melles et al., (1994). The total core length was 240 cm. This core was stored in the dark, at 0 degrees C until required. Samples were taken for diatom analyses and radiocarbon (14C) dating. Prior to sub-sampling the core was split in half, along its length. One half was used for sampling, the other kept intact and stored at IASOS (University of Tasmania). To reduce potential contamination, resulting from the disturbance of sediments during the core-splitting procedure, a thin layer of sediment was removed from the exposed surface immediately prior to sampling.

In order to obtain samples for diatom analysis, a toothpick was inserted into the core segment, and used to gouge a small amount of sediment from the middle of the core. Samples for diatom analyses were initially collected every 5 mm, however, sampling frequency progressively decreased down the core. Samples for radiocarbon data consisted of at least 1 cm 3 of sediment, collected from the middle of the core. These samples were collected from between 0-1 cm, 12-13 cm, 59-60 cm, 77-78 cm, 117-118 cm, and 229-230 cm depth.

Diatom data are presented as raw counts, benthic abundances, the ratio of benthic to plankton species, and as the benthic index. Calculated ages (in years) are also given for all samples. The sedimentological core log is given as a powerpoint presentation.

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
Benthic %
Planktonic %
Depth (cm)
Age (years)
Radiocarbon Age
Corrected Age
Benthic Index

沉积物岩芯采集于鸽子岛（Pidgeon Island）西侧（南纬66.3216°，东经110.445°），水深82.0米。该沉积物岩芯（PG 1411-2）采用释放控制式活塞取芯器（长度3米）获取，取芯技术参考Melles等人（1994）所述方法。岩芯总长度为240厘米，避光储存在0℃环境中直至使用。采集样品用于硅藻（diatom）分析和放射性碳（14C）测年。分样前，岩芯沿长度方向一分为二：一半用于取样，另一半保持完整并储存在塔斯马尼亚大学的IASOS。为减少岩芯分割过程中沉积物扰动可能带来的污染，取样前立即去除暴露表面的薄层沉积物。

为获取硅藻分析样品，将牙签插入岩芯段，从岩芯中部挖取少量沉积物。硅藻分析样品初始每5毫米采集一次，但沿岩芯深度方向取样频率逐渐降低。放射性碳测年样品取自岩芯深度0-1厘米、12-13厘米、59-60厘米、77-78厘米、117-118厘米及229-230厘米处，每个样品至少含1立方厘米沉积物。

硅藻数据以原始计数、底栖丰度、底栖与浮游物种比值及底栖指数呈现。所有样品均提供计算年龄（单位：年）。沉积岩芯记录以PowerPoint演示文稿形式呈现。

本研究作为ASAC项目1130（ASAC_1130）及项目2201（ASAC_2201）的部分内容完成。

项目1130公共摘要：

藻席（algal mats）生长于大多数浅海环境的海床。在许多此类区域，藻席被认为贡献了超过一半的总初级生产力，是无脊椎动物及部分鱼类的关键食物来源。本项目将明确藻席在南极海洋环境中的重要性，确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席的作用。

项目2201公共摘要：

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，澳大利亚致力于全面保护南极环境。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，以便事先评估其对南极环境的潜在影响并做出知情判断。我国在南极的大部分活动集中于毗邻海洋的狭窄无冰岩石带，许多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高的动植物群落，但我们对其了解甚少，远不足以就潜在环境影响做出知情判断。

海床动植物被广泛认为是海洋生态系统中指示本地源扰动的最适部分。附着海床生物与特定地点存在固定空间关系，因此它们要么适应环境要么死亡。一旦从某地点消失，重新定殖需一定时间，因此海床群落结构不仅反映当前环境，还能整合过去的环境状况。相比之下，鱼类和浮游生物可自由移动，因此其捕获地点无法表明它们在该位置长期栖息。由于海床群落多样性极高，包含具有不同生活策略的物种，因此不同物种对压力的耐受程度差异显著；这导致群落结构对逐渐增加的扰动产生一系列细微变化，而非全有或全无的响应。

本项目将调查我方考察站附近的海床群落，以确定人类活动对其影响的严重程度。这些信息将用于确定优先事项，改进操作程序，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）、站点（Site）、底栖百分比（Benthic %）、浮游百分比（Planktonic %）、深度（单位：厘米，Depth (cm)）、年龄（单位：年，Age (years)）、放射性碳年龄（Radiocarbon Age）、校正年龄（Corrected Age）、底栖指数（Benthic Index）