MAC-EXP: Development of a pressurised sampling, experimentation and cultivation system for deep-sea sediments

MAC-EXP：开发深海沉积物加压采样、实验和培养系统

• 批准号: NE/I023465/1
• 负责人: Ursula Witte
• 金额: $ 54.84万
• 依托单位: University of Aberdeen
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FI023465%2F1
• 关键词: MAC; EXP; Development; pressurised; sampling

Most deep-sea organisms live under high pressure in the so-called piezosphere (the volume of the deep-sea at > 1000 m of water depth or > 10MPa pressure) and depend on organic particles sinking down from the surface waters for food. The most abundant organisms by far in marine sediments are prokaryotes (bacteria and archaea), and the biomass of the bacteria and archaea is so great that they are thought to be the main agents of the remineralisation of organic matter, a process which releases nutrients back into the water column and is thus very important for ocean productivity and, for example, fisheries. But our knowledge of deep-sea prokaryote diversity and ecosystem function is scarce. With fishing, mining, oil and gas exploration increasingly taking place in deeper waters, we urgently need to improve our understanding of the functioning of deep-sea ecosystems in order to assess appropriately the societal and economic implications of such activities and impacts and to ensure adequate management of deep-sea biodiversity and natural resources for future generations.Unfortunately, this is not easy: the main reasons for our limited knowledge of deep-sea biodiversity and ecosystem functioning lies in the combination of its inaccessibility with the sensitivity to depressurization of deep-sea organisms and deep-sea biogeochemical processes. Pressure has significant effects on, for example, bacterial physiology or growth rates, as well as many biogeochemical processes that microorganisms are involved in. In consequence, meaningful experimentation has to be carried out under in situ pressure, which results in major financial and technical constraints. Remotely Operated Vehicles allow us to conduct experimental research at the deep-sea floor, but although now possible, this is still very risky and resource-intensive, requiring sophisticated deep-sea ROVs, operated by large crews from large vessels (e.g. 11 technical staff accompany a deployment of the French deep-sea ROV VICTOR 6000; and a large research ship is needed to accommodate and deploy it), and to-date very few such systems are available. In addition, samples in most cases suffer depressurization upon retrieval. As many deep-sea microorgansims may only be culturable without depressurization, this may explain why less than 1 % of deep-sea prokaryotes can currently be cultured. Here we propose to develop a flexible, cost-effective alternative to in situ experimentation: a pressure-coring, experimentation and cultivation system that enables studies of deep-sea prokaryote biodiversity and ecosystem functioning, under ambient or manipulated pressure, temperature and oxygen conditions from any medium sized ocean going research ship with coring capability. In addition, the constant high pressure chain from sampling to culture overcomes limitations of in situ experiments related to depressurisation.This Multiple-Autoclave-Coring and Experimentation system (MAC-EXP) will provide the possibility to systematically test the influence of environmental parameters, such as pressure, oxygen availability or pH on deep-sea organisms and their biochemistry, as well as on rates and pathways of biogeochemical and geomicrobial processes. The system will also allow pioneering work in the field of marine biodiscovery: secondary metabolites from marine microorganisms are a rich source of chemical diversity and several marine-microbe derived compounds are now in clinical trials. Recent evidence shows that pressure-adapted bacteria from deep-sea sediments produce biologically active and unusual secondary metabolites. But no pressure-adapted bacterial species have ever been investigated for their secondary metabolites and the proposed pressurised sampling system provides the possibility to conduct such studies.

大多数深海生物生活在高压下的所谓的压气圈（水深超过1 000米或压力超过10兆帕的深海体积）中，依靠从表面沃茨下沉的有机颗粒为食。迄今为止，海洋沉积物中最丰富的生物是原核生物（细菌和古生菌），细菌和古生菌的生物量如此之大，以至于它们被认为是有机物再矿化的主要媒介，这一过程将营养物质释放回水体，因此对海洋生产力和渔业等非常重要。但我们对深海原核生物多样性和生态系统功能的了解却很少。随着捕鱼、采矿、石油和天然气勘探越来越多地在更深的沃茨进行，我们迫切需要提高对深海生态系统运作的认识，以便适当评估这些活动和影响的社会和经济影响，并确保为子孙后代充分管理深海生物多样性和自然资源。我们对深海生物多样性和生态系统功能的了解有限，主要原因在于无法进入深海生物多样性和深海生物地球化学过程对减压的敏感性。压力对例如细菌生理学或生长速率以及微生物参与的许多生物地球化学过程具有显著影响。因此，必须在原地压力下进行有意义的实验，这造成了重大的财政和技术限制。遥控潜水器使我们能够在深海海底进行实验性研究，但尽管现在已经成为可能，但这仍然非常危险和资源密集，需要由大型船只上的大型船员操作的复杂深海遥控潜水器（例如，11名技术人员陪同部署法国深海探测器VICTOR 6000;并且需要大型研究船来容纳和部署它），并且迄今为止很少有这样的系统可用。此外，在大多数情况下，样品在取回时会减压。由于许多深海微生物可能只能在没有减压的情况下培养，这可以解释为什么目前只有不到1%的深海原核生物可以培养。在这里，我们建议开发一个灵活的，具有成本效益的替代原位实验：压力取芯，实验和培养系统，使深海原核生物多样性和生态系统功能的研究，在环境或操纵压力，温度和氧气条件下，从任何中型远洋研究船取芯能力。此外，从采样到培养的恒定高压链克服了与减压相关的原位实验的局限性。这种多重高压灭菌器取心和实验系统（MAC-EXP）将提供系统测试环境参数的影响的可能性，例如压力、氧气可用性或pH值对深海生物及其生物化学的影响，以及地球化学和地质微生物过程的速率和途径。该系统还将使海洋生物发现领域的开拓性工作成为可能：海洋微生物的次级代谢产物是化学多样性的丰富来源，若干海洋微生物衍生化合物目前正在进行临床试验。最近的证据表明，深海沉积物中适应压力的细菌产生具有生物活性和不寻常的次级代谢产物。但尚未对压力适应性细菌物种的次级代谢产物进行过研究，而拟议的加压采样系统为进行此类研究提供了可能性。

项目成果

A System for Retrieval and Incubation of Benthic Sediment Cores at In Situ Ambient Pressure and under Controlled or Manipulated Environmental Conditions

一种在原位环境压力和受控或操纵的环境条件下回收和孵化底栖沉积物核心的系统

• DOI: 10.1175/jtech-d-16-0248.1
• 发表时间: 2017
• 期刊: Journal of Atmospheric and Oceanic Technology
• 影响因子: 2.2
• 作者: Jackson K

Living benthic foraminiferal assemblages of a transect in the Rockall Trough (NE Atlantic)

• DOI: 10.1016/j.dsr.2021.103509
• 发表时间: 2021-05
• 作者: Bianca Lintner;M. Lintner;P. Bukenberger;U. Witte;P. Heinz