Collaborative Research: Hydrothermal Processes on the Gakkel Ridge

合作研究：Gakkel 海脊的热液过程

• 批准号: 0425565
• 负责人: Henrietta Edmonds
• 金额: $ 10.01万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-15 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0425565&HistoricalAwards=false
• 关键词: Collaborative; Research; Hydrothermal; Processes; Gakkel

This is a collaborative proposal from Principal Investigators from Woods Hole Oceanographic Institution (WHOI) and the University of Texas-Austin. They will study hydrothermal processes on the Gakkel Ridge in the Eastern Arctic Basin. The Gakkel Ridge is a key target for hydrothermal studies because it has distinctive geological characteristics as a result of ultra-slow spreading and it is hydrographically isolated from the world's ocean basins, which have important implications for vent field biological communities. Although thermal and particulate signatures indicative of hydrothermal fluids were found in nearly 80% of the CTD casts from the recent U.S./German Arctic Mid-Ocean Ridge Expedition (AMORE) in 2001, no vent fields have been sampled because the ice cover precludes the use of ROVs and submersibles. The Principal Investigators will solve the technical challenges imposed by the ice pack by utilizing nested surveys with autonomous underwater vehicles (AUVs) to map water column plumes, locate buoyant plume stems, conduct fine-scale micro-bathymetric surveys, and to generate photomosaics of the biological communities. They will use the AUV survey data to identify geological and biological sampling targets, and then use a combination of wireline and semi-autonomous methods to obtain the samples. They will complement and guide the AUV and sampling efforts with a more traditional, comprehensive CTD/hydrocast program to measure key parameters such as methane, hydrogen, and manganese in the overlying hydrothermal plumes. These chemical measurements will provide a first indication of important vent fluid characteristics such as the redox environment and the involvement of ultramafic rocks. Based on the CTD, dredging, and mapping results from the AMORE expedition, the Principal Investigators identified two target areas with contrasting geological characteristics. They have leveraged the funds requested from NSF with a NASA Astrobiology grant recently awarded to WHOI and the University of Maryland's Space Systems Laboratory. NASA's interests lie in technology development for autonomous extra-terrestrial sample return, and the grant provides more than $3M to support the AUV component for the field program as an analogue for future missions to Europa. In this current project, they request funds solely for water column CTD work, wireline sampler development, and sample analyses. Broader Impacts: Hydrothermal circulation is a fundamental physical process within the Earth that gives rise to spectacular deep-sea vent fields hosting exotic, chemosynthetic biological communities. Deep-sea vent fields have provided an exciting, multi-disciplinary field of research since their initial discovery in 1977, and the potential for organic compounds to be abiotically synthesized in deep-sea hydrothermal systems may prove to have profound implications for the origin of life on our planet. This research will extend our knowledge of these systems by characterizing hydrothermal processes on a geologically and hydrographically unique mid-ocean ridge. These topics have broad societal interest, and will bring appropriately packaged aspects of the research to the public through a formal education and outreach component already funded in the NASA Astrobiology grant. These activities will include the development of educational modules by a teacher for the highly acclaimed Dive and Discover website (http://www.divediscover.whoi.edu), followed by their participation in the Gakkel expedition and will bring the cruise activities to middle and high school classrooms and to the general public in near real-time. WHOI and the University of Maryland's Space Systems Lab have obtained a grant from NASA's Astrobiology Science and Technology Experiment +Program (ASTEP) that has provided more than $3M to merge robotics technologies with AUVs to enable autonomous sample collection for future missions to Europa, and to demonstrate the system by performing remote sampling of hydrothermal vents in the Arctic Ocean. The NASA grant will support the AUV component of Arctic Ocean field program.One of the proposed options in the ANS proposal for sample recovery is to use a simple, towed system with real-time data return and shipboard control for triggered sampling. This sampling platform has no thrusters, so it cannot be maneuvered except by moving the ship, but it can operate independently and provides a relatively inexpensive system for high quality imaging and sampling at Arctic deepsea vent fields. The Drop Camera System (DCS) consists of a metal frame that includes a digital camera, lights, a depth sensor, a CTD, and a mechanical sampling device capable of multiple samples. The conceptual idea is to use a combination of a claw-style dredge and a slurp gun that can be lowered for sampling with a set of rotating sampling containers. The entire frame would be connected to the icebreaker using standard 0.68" EMO cable. The DCS will be navigated using a relay transponder near the end of the wire and a long-baseline transponder network that will be deployed on the seafloor at each target site (these transponders will also be used to help navigate the AUV surveys). The software interface will be derived from software that runs the National Deep Submergence Facility towed vehicle Argo and associated platforms. All data is converted to ethernet via ethernet-to-RS232 interface converters and analog controlled circuitry. The camera imagery is available in digital format and will be packeted for telemetry. The ethernet data will be piped up the fiber to the surface via a ethernet fibre converter, where it will be logged, displayed in real-time, and also used to allow for individual sensor parameter control. A similar software and control system has already been developed at WHOI and deployed on the shallow water "Habcam" towed system for biological habitat characterization. After seafloor vent field targets have been identified through a combination of CTD and AUV surveys, the Principal Investigators will use the icebreaker to clear a lead for the DCS deployment. They will plan the deployment so that the icebreaker will drift with the ice pack over the target area. In a typical deployment scenario, the DCS will be towed 5-10 meters above the seabed at slow speeds. High dynamic range imagery will be telemetered in real-time to the icebreaker allowing them to make linear photomosaics of the seafloor, and will have command-control capability to deploy the sampler based on the real time digital imagery.

这是伍兹霍尔海洋研究所（WHOI）和德克萨斯大学奥斯汀分校首席研究员的合作提案。他们将研究北极东部盆地Gakkel Ridge的热液过程。Gakkel Ridge是热液研究的一个关键目标，因为它具有独特的地质特征，因为它的扩张速度极慢，并且在水文上与世界海洋盆地隔离，这对喷口场生物群落具有重要意义。尽管2001年美国/德国北极洋中脊考察队（AMORE）近80%的CTD样品中都发现了热液流体的热特征和颗粒特征，但由于冰层覆盖阻碍了rov和潜水器的使用，因此没有对喷口区进行采样。首席研究人员将利用自主水下航行器（auv）的嵌套调查来绘制水柱羽流图，定位浮力羽流系统，进行精细的微深度测量，并生成生物群落的显微图像，从而解决浮冰带来的技术挑战。他们将使用AUV调查数据来确定地质和生物采样目标，然后结合使用电缆和半自主方法来获取样本。他们将补充和指导AUV和采样工作，采用更传统、更全面的CTD/hydrocast程序来测量上覆热液羽流中的甲烷、氢和锰等关键参数。这些化学测量将提供重要的喷口流体特征的初步指示，如氧化还原环境和超镁质岩石的参与。根据AMORE考察的CTD、疏浚和测绘结果，主要研究人员确定了两个地质特征截然不同的目标区域。他们利用了美国国家科学基金会（NSF）申请的资金，以及最近授予WHOI和马里兰大学空间系统实验室的美国宇航局天体生物学补助金。NASA的兴趣在于自主地外样本返回的技术开发，这笔拨款提供了300多万美元，用于支持野外项目的AUV组件，作为未来木卫二任务的模拟。在目前的项目中，他们要求的资金仅用于水柱CTD工作、电缆取样器开发和样品分析。更广泛的影响：热液循环是地球内部一个基本的物理过程，它产生了壮观的深海喷口，孕育着奇异的化学合成生物群落。深海热泉自1977年首次被发现以来，提供了一个令人兴奋的、多学科的研究领域，深海热液系统中有机化合物非生物合成的潜力可能被证明对我们星球上生命的起源具有深远的意义。这项研究将通过在地质和水文上独特的洋中脊上表征热液过程来扩展我们对这些系统的认识。这些主题具有广泛的社会利益，并将通过NASA天体生物学拨款资助的正式教育和推广部分，将适当包装的研究方面带给公众。这些活动将包括由一名教师为广受好评的Dive and Discover网站（http://www.divediscover.whoi.edu）开发教育模块，随后他们将参与Gakkel探险，并将邮轮活动带到初中和高中的教室以及接近实时的公众。WHOI和马里兰大学空间系统实验室已获得美国宇航局天体生物学科学与技术实验+计划（ASTEP）的资助，该计划已提供300多万美元，用于将机器人技术与auv相结合，为未来的木卫二任务提供自主样本收集，并通过对北冰洋热液喷口进行远程采样来演示该系统。NASA的拨款将支持北冰洋野外项目的AUV组件。在ANS方案中，对于采样恢复的建议之一是使用一个简单的拖曳系统，该系统具有实时数据返回和船载控制，用于触发采样。该采样平台没有推进器，因此只能通过移动船舶来操纵，但它可以独立运行，并为北极深海喷口区域的高质量成像和采样提供相对便宜的系统。跌落相机系统（DCS）由一个金属框架组成，该框架包括数码相机、灯、深度传感器、CTD和能够进行多个采样的机械采样装置。概念上的想法是使用爪式挖泥船和吸音枪的组合，可以降低采样与一组旋转采样容器。整个框架将使用标准的0.68英寸EMO电缆连接到破冰船上。DCS将使用靠近电缆末端的中继应答器和将部署在海底每个目标站点的长基线应答器网络进行导航（这些应答器也将用于帮助导航AUV调查）。软件接口将来源于运行国家深潜设施拖曳车辆Argo和相关平台的软件。所有数据通过以太网到rs232接口转换器和模拟控制电路转换到以太网。相机图像以数字格式提供，并将打包用于遥测。以太网数据将通过以太网光纤转换器通过光纤管道传输到地面，在那里它将被记录，实时显示，也用于允许单个传感器参数控制。WHOI已经开发了一个类似的软件和控制系统，并将其部署在浅水“Habcam”拖曳系统上，用于生物栖息地特征描述。在通过CTD和AUV调查确定海底喷口区域目标后，首席调查员将使用破冰船为DCS部署扫清道路。他们将计划部署，以便破冰船随浮冰漂移到目标区域。在一个典型的部署场景中，DCS将以缓慢的速度被拖到海床以上5-10米的地方。高动态范围图像将实时遥测到破冰船，使他们能够制作海底的线性光学图像，并将具有基于实时数字图像部署采样器的命令控制能力。