Gascoyne Marine Park Post-survey report, RV Falkor, FK200308 (GA4859)

The deep waters within the Gascoyne Marine Park have been largely unexplored for their seafloor biodiversity. Survey FK200308 on the RV Falkor targeted two canyons within the Gascoyne Marine Park to understand and map the distribution and diversity of marine habitats and biota within the Cape Range and Cloates Canyons. These canyons were targeted to better understand their ecological significance as a conduit between shelf environments adjacent to the Ningaloo Reef and the abyssal plain. They occur within the habitat protection and multiple use zones of the Gascoyne Marine Park off north-western Australia.Survey FK200308 was led by researchers at the Western Australian Museum, and included scientists from Geoscience Australia, Curtin University, Macquarie University and Scripps Institute of Oceanography. Multibeam sonar was used to map parts of the marine park, while a Remotely Operated Vehicle (ROV) was deployed to undertake a comprehensive taxon inventory of the North-West canyon fauna based on underwater imagery and sampling. Additional biological samples were collected via plankton sampling, as well as fish and crustacean traps on a lander, and stand-alone fish trap deployments. Autonomous Reef Monitoring Structures (ARMS) were deployed at select sites to capture cryptic benthic organisms over several years. DNA samples from the water column (eDNA) were collected to enable a broader understanding of the biodiversity of the region, and to provide a methodological comparison to the organisms present at the time of sampling.The key drivers for this survey were to collect Information to enhance our understanding of the Gascoyne Marine Park and deep-sea environments throughout Western Australia, and to facilitate comparisons between the north-west and eastern and southern Australian deep-sea waters. This information can be applied to inform management plans, scientific research and industry activities for the North-West. Specifically, this survey provided:•    A faunal inventory as a baseline information for monitoring deep water WA environments. A total of 2570 seafloor images were annotated from quantitative transects, more than 1000 specimens were collected and up to 30 new species discovered.•    High resolution mapping of the seafloor across an area of 11,250 km2 revealed a detailed understanding of seabed habitats and environments in the Gascoyne Marine Park, and a regional context in which to interpret the faunal inventory.•    Repeat multibeam mapping of the Cape Range and Cloates Canyons informed our understanding of seabed stability in the canyons of the Gascoyne Marine park, illustrating a rare case of true monitoring using multibeam in Australian waters.•    The use of a state-of-the-art ROV across 20 deployments helped inform a new ROV field manual (Monk et al. 2020), adding to the existing suite of standard operating procedures supported by Parks Australia (https://marine-sampling-field-manual.github.io/).This survey confirmed that canyons within the Gascoyne Marine Park are important ecological systems, supporting numerous deep-sea species, many of which were discovered to be new to science. The advanced capabilities of the ROV SuBastian to navigate and image complex near vertical walls and overhangs within the canyons revealed patterns in the distribution of the seafloor taxa consistent with small-scale environmental variability. Repeat multibeam mapping revealed a dynamic canyon system that continues to be shaped by turbidity events. The occurrence of reworked seagrass blades within the canyons provided new understanding of these canyon systems as an active conduit between shallow shelf and abyssal environments. The distribution of the seabed biota revealed through quantitative ROV transects emphasised the importance of disturbance patterns in shaping the canyon ecosystems.

加斯科因海洋保护区（Gascoyne Marine Park）内的深水海域，其海底生物多样性长期以来基本未被探索。搭载于Falkor号科考船（RV Falkor）的FK200308号科考航次，以该保护区内的两处峡谷——开普岭峡谷（Cape Range Canyon）与克洛茨峡谷（Cloates Canyon）为研究目标，旨在探明并绘制这两处峡谷内的海洋生境与生物群落的分布及多样性特征。选择这两处峡谷开展研究，是为了更深入理解其作为毗邻宁格罗礁（Ningaloo Reef）的陆架环境与深海平原之间的生态廊道的生态重要性。这两处峡谷位于澳大利亚西北海域的加斯科因海洋保护区内的生境保护与多用途区域中。

本次FK200308号科考航次由西澳大利亚博物馆（Western Australian Museum）的研究人员牵头，合作方包括澳大利亚地质调查局（Geoscience Australia）、科廷大学（Curtin University）、麦考瑞大学（Macquarie University）以及斯克里普斯海洋研究所（Scripps Institute of Oceanography）的科研人员。研究团队采用多波束声呐（Multibeam sonar）对保护区部分区域进行海底测绘，并部署遥控水下机器人（Remotely Operated Vehicle, ROV），依托水下影像与采样工作，对西北峡谷的动物群落开展全面的分类单元编目。此外，研究团队通过浮游生物采样、搭载于着陆器的鱼类与甲壳动物陷阱，以及独立部署的鱼类陷阱，采集了额外的生物样本。研究团队在选定站点部署了自主珊瑚礁监测结构（Autonomous Reef Monitoring Structures, ARMS），以在数年周期内采集隐秘底栖生物样本。采集水体环境DNA（eDNA）样本，以更全面地了解该区域的生物多样性，并为采样时获取的生物样本提供方法学层面的对比参照。

本次科考航次的核心目标为：采集相关数据，以加深对加斯科因海洋保护区及西澳大利亚全域深海环境的认知，并助力开展澳大利亚西北海域与东、南部深海海域的对比研究。这些数据可为西北海域的管理规划、科学研究及产业活动提供决策依据。具体而言，本次航次取得了以下成果：
• 构建动物群落编目，作为西澳大利亚深水环境监测的基准数据。本次航次共对定量样带中的2570张海底图像进行了标注，采集了超过1000份生物标本，发现了多达30个新物种。
• 对11250平方千米的海底区域开展高分辨率测绘，详细解析了加斯科因海洋保护区内的海底生境与环境特征，并为动物群落编目提供区域背景参照。
• 对开普岭峡谷与克洛茨峡谷开展重复多波束测绘，增进了对加斯科因海洋保护区内峡谷海底稳定性的认知，这也是澳大利亚海域内罕见的采用多波束声呐开展的长期监测案例。
• 本次航次共开展20次最先进遥控水下机器人部署作业，相关经验为新版《遥控水下机器人野外作业手册》（Monk等人，2020）提供了依据，进一步完善了由澳大利亚公园管理局（Parks Australia）支持的现有标准作业程序体系（https://marine-sampling-field-manual.github.io/）。

本次科考航次证实，加斯科因海洋保护区内的峡谷属于重要的生态系统，栖息着大量深海物种，其中诸多物种为科学新发现。SuBastian号遥控水下机器人具备优异的导航与成像能力，可在峡谷内的复杂近垂直壁与悬垂结构区域开展作业，其采集的数据揭示了海底分类群的分布模式与小尺度环境变异的一致性。重复多波束测绘结果显示，该峡谷系统处于动态变化中，仍受浊流事件持续塑造。峡谷内发现的再沉积海草叶片，为理解该峡谷系统作为浅海陆架与深海环境间的活跃生态廊道提供了新的认知依据。通过遥控水下机器人定量样带获取的海底生物分布数据，进一步凸显了干扰模式在塑造峡谷生态系统过程中的重要性。