SS2004/04 - Testing, refinement and application of methodology for optimised seabed mapping : Sediment samples

This voyage provides an opportunity to test and refine optimal techniques to map and assess seabed habitat developed in a previous CMR project (NOO OP2000-SE02). Importantly, this voyage will use the National Facility's high-resolution EM300 swath mapper for its first program of biological and physical habitat mapping. The sampling locations are a number of submarine canyons and their immediately adjacent flanks on the west coast of Tasmania and east of Bass Strait. These are prime targets for our methods development because each canyon area is characterised by a great variety of seabed topography and benthic communities concentrated in a relatively small area (< 300 sq km). This voyage is also an opportunity to apply the data collected to marine resource management planning in the South East Region. Submarine canyons represent a type of habitat unit ("Level 3 biogeomorphic units") having a strong influence on the location of offshore Marine Protected Areas on the continental slope and rise, and many are likely to be biodiversity "hotspots". Several canyons are also the locations of the largest known aggregations of feeding and spawning fishes in the South-East Fishery region, and these support a range of intense, increasing and, in places, conflicting fishing activities. Given the immediate and increasing relevance of submarine canyons to conservation and fishery managers, it is then surprising to realize that virtually all those in the SE region remain unsampled by scientists, and are named only by commercial fishers. For these reasons, sampling on this voyage will focus on the "Big Horseshoe Canyon" mapped previously with the EM1002 and EM12 swath instruments (to enable comparison of data types, and to investigate temporal persistence of features), and several "new" areas. Sediment samples were taken for analysis by Geoscience Australia.

本次航次为测试并优化此前CMR项目（NOO OP2000-SE02）中开发的海底栖息地测绘与评估最优技术提供了契机。尤为重要的是，本次航次将首次依托国家设施的高分辨率EM300条带测绘仪（EM300 swath mapper）开展生物与物理栖息地测绘项目。本次采样的点位涵盖塔斯马尼亚西海岸与巴斯海峡东侧的多处海底峡谷及其紧邻侧翼。这些区域是方法开发的理想靶区，因为每处峡谷区域均具备多样的海底地形特征，且底栖生物群落集中于相对狭小的范围（<300平方千米）。本次航次还可将采集的数据应用于东南海域的海洋资源管理规划。海底峡谷属于一类栖息地单元——“三级生物地貌单元（Level 3 biogeomorphic units）”，对大陆坡与陆隆区域的近海海洋保护区（Marine Protected Areas）选址具有显著影响，且多数区域极有可能为生物多样性“热点”。多处峡谷同时是东南海域渔业中已知规模最大的索饵与产卵鱼类集群所在地，这些区域支撑了一系列高强度、持续增长且在部分区域存在冲突的捕捞活动。鉴于海底峡谷与资源保护及渔业管理的相关性日益凸显且迫在眉睫，令人意外的是，东南海域几乎所有海底峡谷均未经过科学家系统采样，仅由商业渔民命名。基于上述原因，本次航次的采样将聚焦于此前利用EM1002与EM12条带测绘仪（EM1002 and EM12 swath instruments）测绘的“大马蹄形峡谷（Big Horseshoe Canyon）”（以实现不同数据类型的对比，并探究地貌特征的时间持续性），以及多处“新”区域。澳大利亚地质调查局（Geoscience Australia）将对本次采集的沉积物样品开展分析。