Kelp rafts in the Southern Ocean: intercontinental travel for sessile and semi-sessile organisms 2010

Metadata record for data from ASAC Project 2914 See the link below for public details on this project. Can animals raft between countries on floating seaweed? We aim to answer that question using powerful genetic tools. We can tell whether gene flow is strong between populations of animals by comparing their mitochondrial DNA; this could show us whether animals from one species in New Zealand are isolated from individuals of the same species in Chile. If they are not isolated, how are they managing to maintain gene flow? We know there are many millions of clumps of floating seaweed in the Southern Ocean, and these might provide a means of intercontinental travel for a range of small invertebrates. Project objectives: The primary objective of the project is to determine the effectiveness of rafting as a dispersal mechanism for sessile and semi-sessile organisms around the Southern Ocean using genetic tools. The secondary objectives, by which the primary objective will be addressed, are: - to examine the biogeography of bull kelp (Durvillaea antarctica) and its holdfast fauna around the Southern Ocean - to undertake genetic analysis of a wide range of macroalgal (seaweed) species throughout the Southern Ocean to assess 1) whether sea ice indeed extended further north than previously believed, and 2) the ecological and evolutionary impacts of historic ice scour on Southern Ocean islands. - to determine which holdfast invertebrates are the most common and ubiquitous in holdfasts of Durvillaea antarctica around the Southern Ocean - to compare the genetic structure of populations of both the kelp itself, and select invertebrate taxa* from its holdfasts, on a number of spatial scales: --- genetic variation at HOLDFAST level: are members of a single species, e.g., the isopod Limnoria stephenseni, closely related within a single holdfast? --- genetic variation at SITE level: are members of a single species, e.g., Durvillaea antarctica itself, closely related at one site? In this case, a 'site' means a single intertidal rock platform. --- genetic variation at NATIONAL level: are there distinct biogeographic separations of species, or does a single species show distinct genetic disjunction, along the Chilean coastline and around the south island of New Zealand? --- genetic variation at OCEAN level: are species clearly connected (by gene flow) between Southern Ocean landmasses? The landmasses of interest are: Chile, New Zealand, and the subantarctic islands on which Durvillaea antarctica grows. * The proposed taxa that this project will focus on are: the isopod genus Limnoria; the amphipod Parawaldeckia kidderi; the chiton genus Onithochiton; the polychaete worm families Terebellidae and Syllidae; a topshell; a bivalve; barnacles. Progress against objectives: Considerable progress has been made against the primary objective since the start of the project in 2006. We have collected (/ been sent) and analysed samples of bull-kelp (Durvillaea antarctica) and its associated invertebrate holdfast fauna from numerous sites around the Southern Ocean (subantarctic islands including Macquarie, Gough, Marion, Kerguelen, Crozet, Auckland, Antipodes, Campbell, Falkland Islands; along the coasts of New Zealand and Chile). Our results thus far have allowed us to determine not only that rafting facilitates long-distance dispersal of these otherwise sedentary taxa, but also that sea ice during the last ice ice likely had significant impacts on subantarctic intertidal ecosystems. Our conclusions have been published in several papers in high-impact journals. The secondary objectives, by which the primary objective will be addressed, are: - to examine the biogeography of bull kelp (Durvillaea antarctica) and its holdfast fauna - these objectives have now largely been achieved, and results published. - to undertake genetic analysis of a wide range of macroalgal (seaweed) species throughout the Southern Ocean - this part of the project is ongoing, and will make use of samples collected over the austral summer from Macquarie Island (and other locations around the southern hemisphere). all samples have now been collected and are being processed in the laboratory. - to determine which holdfast invertebrates are the most common and ubiquitous - this objective has been partially achieved (see Nikula et al. 2010), but research is ongoing. - to compare the genetic structure of populations of both the kelp itself, and select invertebrate taxa from its holdfasts, on a number of spatial scales - this objective has been partially achieved (see Nikula et al. 2010 for results of Limnoria and Parawaldeckia genetic research) but additional research on these and other taxa continues. The download file contains an excel spreadsheet detailing collection locations and accession numbers for the samples collected on Macquarie Island. A text document providing accession numbers for non-Antarctic related samples used in this project is also part of the download file. Quality: The figures provided in temporal and spatial coverage are approximate only. Taken from the 2009-2010 progress report: Field work: During the 2009/2010 season, Dr James Doube and other AAD personnel based at Macquarie Island were able to collect the macroalgal samples we requested. Field work was undertaken at two sites close to the Base: one on the east coast (Garden Cove, 57F 0496283 3960990) and one on the west coast (Cosray Rocks, 57F 0495752 3960973). Fieldwork involved collection of small samples of intertidal seaweeds (macroalgae) from rock platforms at Macquarie Islands. Samples were preserved in ethanol, and couriered to our department at the University of Otago. These samples were received on 14 May 2010, and are now being processed in the laboratory. Field work for the broader project is ongoing - however, during the 2009 / 2010 summer, we collected (or were sent) samples from: - the Falkland Islands - central Chile - southern Chile (fiordland) - the New Zealand subantarctic (Campbell, Auckland, Snares, Antipodes and Bounty Islands) - Kerguelen Island - Marion Island - Gough Island - Tasmania, Australia Difficulties affecting project: Not all target species of seaweed were obtained from all collection sites (both at Macquarie Is and elsewhere) - however, on the whole we have obtained most of our target taxa from a broad range of subantarctic locations. Note from AADC, 2018-08-03: The original datasheet was reformatted to fit OBIS/GBFI/IPT Biodiversity.AQ standardS. The new datasheet \"KelpRafts.csv\" provides the dataset from Macquarie Island samples. Contains datasetID, occurrenceID, event date, decimal latitude, decimal longitude. The lowest taxonomical rank of the species identified that could be determined is provided, after matched in WoRMS (World Register of Marine Species). As the data is genetics identification the associatedSequence and associatedReferences are provided.ASAC项目2914数据集元数据记录 请点击下方链接查看该项目的公开详情。 动物是否可借助漂浮海藻在各国间进行浮运扩散？本研究旨在借助先进的遗传分析手段解答这一问题。我们可通过比对动物种群的线粒体DNA（mitochondrial DNA），判断其种群间基因流（gene flow）强度，以此揭示新西兰某一物种的个体是否与智利同种个体存在生殖隔离。若二者不存在隔离，它们又是如何维持种群间的基因交流的？已知南大洋中存在数以百万计的漂浮海藻团块，这类海藻或可为多种小型无脊椎动物提供跨洲际移动的载体。 ### 项目目标 本项目的首要目标为：借助遗传分析手段，明确浮运扩散作为南大洋周边固着及半固着生物扩散机制的有效性。 为达成首要目标，本项目设定如下次要目标： - 研究南大洋周边牛海带（bull kelp, *Durvillaea antarctica*）及其固着器附生动物群落的生物地理学特征 - 对南大洋范围内多种大型藻类（海藻）开展遗传分析，以评估：① 南大洋海冰的实际分布北界是否较此前认知更靠北；② 历史冰蚀作用对南大洋岛屿的生态与进化影响 - 明确南大洋周边南极牛海带（*Durvillaea antarctica*）固着器中最常见且分布最广泛的无脊椎动物类群 - 在多个空间尺度下，对比该海带本身及其固着器中选定的无脊椎动物类群的种群遗传结构： --- **固着器尺度**：同一固着器内的同种个体（如等足类*Limnoria stephenseni*）是否具有较高的亲缘关系？ --- **样点尺度**：同一潮间带岩台（本研究中“样点”指单个潮间带岩台）内的同种个体（如南极牛海带本身）是否具有较高的亲缘关系？ --- **国家尺度**：沿智利海岸及新西兰南岛周边海域，是否存在显著的物种生物地理分隔，或是单一物种在该区域出现明显的遗传分化？ --- **大洋尺度**：南大洋各陆块（即智利、新西兰以及南极牛海带的生存亚南极岛屿）间的物种是否存在明确的基因流关联？ *本项目重点关注的类群包括：等足类（Isopoda）*Limnoria*属、端足类（Amphipoda）*Parawaldeckia kidderi*、石鳖（Chiton）*Onithochiton*属、多毛类（Polychaeta）蛰龙介虫科（Terebellidae）和裂虫科（Syllidae）、一种马蹄螺（topshell）、一种双壳类（bivalve）以及蔓足类（barnacles，即藤壶）。 ### 项目目标完成进展 自2006年项目启动以来，首要目标已取得显著进展。我们已从南大洋周边多个采样点（包括麦夸里岛、戈夫岛、马里恩岛、凯尔盖朗岛、克罗泽岛、奥克兰群岛、安蒂波德斯群岛、坎贝尔岛、福克兰群岛等亚南极岛屿，以及新西兰与智利沿岸）采集/接收并分析了南极牛海带（*Durvillaea antarctica*）及其固着器附生无脊椎动物群落的样本。截至目前，我们的研究结果不仅证实浮运扩散可促进这类固着类群的长距离扩散，还揭示末次冰期的海冰可能对亚南极潮间带生态系统造成了显著影响。相关研究结论已发表于多份高影响力期刊。 针对前述次要目标的完成进展如下： - 研究南极牛海带及其固着器附生动物群落生物地理学特征的目标：已基本完成，相关研究成果已发表。 - 对南大洋多种大型藻类开展遗传分析的目标：本部分研究仍在进行中，将使用南半球夏季期间从麦夸里岛（及南半球其他地点）采集的样本。目前所有样本均已采集完毕，正在实验室中进行处理。 - 明确南极牛海带固着器中最常见且分布最广泛的无脊椎动物类群的目标：已部分完成（详见Nikula等人2010年的研究），相关研究仍在继续。 - 在多个空间尺度下对比该海带及其固着器无脊椎动物类群的种群遗传结构的目标：已部分完成（有关等足类*Limnoria*和端足类*Parawaldeckia*的遗传研究结果详见Nikula等人2010年的研究），针对这些类群及其他类群的补充研究仍在进行。 ### 数据集说明 下载文件包含一份Excel表格，详细记录了麦夸里岛采集样本的采样地点及登录号（accession number）。下载文件中还包含一份文本文件，列出了本项目使用的非南极相关样本的登录号。 数据质量说明：本次提供的时空覆盖范围数据仅为近似值。 本内容取自2009-2010年度项目进展报告： #### 野外工作 在2009/2010年度野外季期间，驻麦夸里岛的James Doube博士及澳大利亚南极署（AAD）其他工作人员成功采集了我们所需的大型藻类样本。野外采样工作在基地附近的两个点位开展：一处位于东海岸的花园湾（Garden Cove，坐标：57F 0496283 3960990），另一处位于西海岸的科斯雷岩（Cosray Rocks，坐标：57F 0495752 3960990）。本次野外工作从麦夸里岛的潮间带岩台采集了小型潮间带海藻（大型藻类）样本。样本用乙醇保存，并通过快递寄送至奥塔哥大学（University of Otago）本课题组。这批样本于2010年5月14日送达，目前正在实验室中进行处理。 本项目整体的野外工作仍在持续，但在2009/2010年夏季期间，我们采集/接收了来自以下地点的样本： - 福克兰群岛 - 智利中部 - 智利南部（峡湾地区） - 新西兰亚南极群岛（坎贝尔岛、奥克兰群岛、斯奈尔斯群岛、安蒂波德斯群岛以及邦蒂群岛） - 凯尔盖朗岛 - 马里恩岛 - 戈夫岛 - 澳大利亚塔斯马尼亚州 #### 项目面临的困难 并非所有目标海藻物种都能从所有采样点（包括麦夸里岛及其他地点）采集获得，但总体而言，我们已从广泛的亚南极采样区域获取了大部分目标类群。 #### 澳大利亚南极数据中心（AADC）2018年8月3日备注 原始数据表已重新格式化，以符合OBIS/GBFI/IPT Biodiversity.AQ标准。新数据表"KelpRafts.csv"包含麦夸里岛样本的数据集，该数据集包含数据集ID、发生记录ID、事件日期、十进制纬度、十进制经度信息。经与世界海洋物种登记册（World Register of Marine Species）匹配后，本数据集提供了可鉴定到的最低分类阶元物种信息。由于本数据集基于遗传鉴定，因此附带了相关序列及参考文献信息。