Fisheries trawling effects on the structure and functioning of marine sediment microorganisms

欧盟海洋战略框架指令（MSFD）要求成员国必须建立一个实现良好环境状态（GES）的措施计划。GES的一个关键描述是海底完整性得到一定程度的保护，确保海底的结构和功能不受不利影响。海底拖网捕捞被公认为是人类对海洋环境最广泛的物理干扰。它可以改变底栖生物[海底]栖息地的物理特性，并损害居住的动物。拖网捕捞如何影响栖息在海洋沉积物中的微生物群落的结构，以及它们从这种影响中恢复所需的时间，人们所知甚少。这些生物主要负责驱动海底碳和氮循环的速率和途径。对拖网再悬浮事件的少量经验观察表明，底栖生物碳和营养物质外流受到影响，尽管研究之间的比较产生了相互矛盾的结果。这些不一致影响了我们有效管理渔业对提供生态系统服务（如碳固存和养分再生）的环境影响的能力。该项目将朝着缩小捕捞渔业对生态系统功能的广泛影响的知识差距迈出重要一步，以及它如何影响英国满足GES关键描述符的能力。它将研究不同程度的扰动强度如何影响1)海底的物理性质；2)居住微生物群落结构；3)它们将有机物再循环为二氧化碳和溶解营养物的能力；4)从生理干扰中恢复所需的时间。在从厘米到公里的空间尺度上，对不同沉积物类型进行了观测和实验，这将使我们更好地理解中小型实验室研究得出的数据与现实世界的影响之间的关系。该项目涉及最先进的稳定同位素指纹识别技术和脉冲追踪实验。监督团队汇集了海洋工程、渔具、岩土技术和生物地球化学方面的专业知识，以及稳定同位素技术和统计建模。案例合作伙伴，苏格兰海洋科学（MSS），为苏格兰政府提供海洋渔业和水生环境方面的专家科学、经济和技术咨询。它们还与渔业密切合作，发展可持续渔业，拟订和发展与商业渔具的设计、操作和部署有关的国家政府政策，以及确定海洋保护区。与科学-政策部门的同事合作，将确保我们的成果直接有助于实现MSFD和其他欧盟指令的目标，包括水框架指令（WFD）和共同渔业政策（CFP）。我们的项目合作伙伴普利茅斯海洋实验室（PML）负责重新开发欧洲区域海洋生态系统模型（ERSEM），其中包括底栖生物过程。这个学生项目产生的数据将有助于对ERSEM进行概念化和参数化，提高国家预测拖网捕捞更广泛的生物地球化学影响的能力。这个多学科的学生将提供实地、实验和实验室技术方面的培训，以及解决问题、沟通技巧和时间管理等通用技能方面的培训。成功的候选人将被整合到南安普敦国家海洋学中心（GSNOCS）研究生院的NERC资助的英国最大的生物科学学生群体之一。

The EUs Marine Strategic Framework Directive (MSFD) mandates that member states must establish a programme of measures for achieving good environmental status (GES). A key descriptor of GES is that seafloor integrity is safeguarded to a level that ensures that the structure and functions of the seafloor are not adversely affected.Fisheries trawling of the seafloor is widely acknowledged as mankinds most widespread physical disturbance in the marine environment. It can alter the physical properties of the benthic [seabed] habitat and impair the resident animals. Very little is known about how trawling affects the structure of the communities of microorganisms that inhabit marine sediments and the time they require to recover from such impacts. These organisms are primarily responsible for driving the rates and pathways of carbon and nitrogen cycling at the seafloor. The few empirical observations of trawl resuspension events suggest that benthic carbon and nutrient effluxes are affected, although comparison between studies yields contradictory results. These inconsistencies confound our ability to effectively manage the environmental impacts of fisheries on the provisioning of ecosystem services such as carbon sequestration and nutrient regeneration.This project will take a major step towards closing the knowledge gap on the broader impacts of capture fisheries on ecosystem functioning, and how it affects the UK's ability to meet key descriptors of GES. It will investigate how different levels of disturbance intensity affect 1) the physical properties of the seafloor; 2) the structure of the resident microbial communities; 3) their capacity to recycle organic material back to carbon dioxide and dissolved nutrients; 4) the time they require to recover from physical disturbance. The proposed work is underpinned by observations and experiments made across different sediment types at spatial scales that range from the cm to the km. This will enable us to better understand how data derived from small- and medium scale laboratory studies relate to real-world effects. The project involves state-of-the-art stable isotope fingerprinting techniques and pulse-chase experiments.The supervisory team brings together expertise in marine engineering, fishing gears, geotechnics and biogeochemistry, along with stable isotope techniques and statistical modelling. The CASE Partner, Marine Scotland Science (MSS), provides expert scientific, economic and technical advice on marine fisheries and the aquatic environment to the Scottish Government. They also work closely with the fishing industry in the development of sustainable fisheries, the formulation and development of national governmental policy in relation to the design, operation and deployment of commercial fishing gears and the identification of Marine Protected Areas (MPAs). Working with colleagues at the science-policy interface will ensure that our results directly contribute towards achieving the objectives of the MSFD and other EU directives, including the Water Framework Directive (WFD) and the Common Fisheries Policy (CFP). Our Project Partner, Plymouth Marine Laboratory (PML) is responsible for redeveloping the European Regional Seas Ecosystem Model (ERSEM), which includes benthic processes. Data generated by this studentship will help conceptualise and parameterise ERSEM, increasing national capability to predict the wider biogeochemical effects of trawling.This multidisciplinary studentship will provide training in field, experimental and laboratory techniques, alongside tuition in generic skills such as problem solving, communication techniques and time management. The successful candidate will be integrated within one of the UK's largest biosciences cohorts of NERC funded students within the Graduate School at the National Oceanography Centre, Southampton (GSNOCS).