Seasonal controls on shelf-edge nutrient fluxes at the Malin Shelf

营养物是海洋中浮游植物生长所必需的。浮游植物从周围的水中吸收养分，它们的生长程度在很大程度上取决于养分的可用性。硝酸盐和磷酸盐是至关重要的营养物质，它们在富光的地表水中的存在可以维持藻华。浮游植物从大气中吸收二氧化碳，在陆架海洋中可以将这些碳锁在沉积物中。在这个项目中，我们将研究大陆架海洋营养物质的季节性供应是由大陆架边缘的物理混合过程控制的。这项工作将使用能够原位测定硝酸盐和磷酸盐的新型传感器进行，这些传感器将被部署在水下滑翔机上，每次最多可使用3周。水下滑翔机是一种自动驾驶的交通工具，从靠近海岸的地方发射后，可以“飞”到采样点，并通过卫星链路发回数据。我们将在一个季节性的时间范围内（2013年6月和9月，2014年1月和4月）使用四次滑翔机任务，以获得对马林大陆架周围高产大陆架海洋每年营养供应的基本洞察。除了营养传感器外，滑翔机上还将安装另外三个传感器，一个是电导率和温度传感器，一个是氧气传感器，一个是可以测定叶绿素a的传感器，叶绿素a被用作水中浮游植物生物量的代表。对于每个任务，我们将使用两个滑翔机同时表征在货架上和在货架上的浓度梯度。这些滑翔机任务将被整合到一个由nerc资助的大型联盟FASTNEt中，该联盟旨在确定促进西北欧大陆架边缘水交换的物理过程，并了解它们如何在季节中演变。FASTNEt将在同一位置部署长期的大陆架边缘流计系泊装置和另一种水下自主航行器Autosub Long Range （ALR）。使用部署在滑翔机上的传感器，我们可以增加数据的空间和时间覆盖范围，这是传统船上测量无法实现的，在暴风雨条件下无法进行。结合对马林陆架发生的物理过程的深入了解，以及来自传感器的准确的高分辨率营养数据，意味着我们将能够研究控制光带营养供应的因素，以及这对浮游植物生长的影响。此外，我们将为这些水下滑翔机试验新的部署方法——使用快速的日间船将它们从沿海基地带到离岸尽可能远的地方。我们的数据将免费提供，我们将在整个项目中与最终用户（如负责渔业的英国政府环境、食品和农村事务部以及英国气象局）分享我们的发现。

Nutrients are essential for phytoplankton growth in the sea. Phytoplankton take up nutrients from the surrounding water and the extent of their growth is largely dependent on nutrient availability. Nitrate and phosphate are vital nutrients and their presence in light-rich surface waters can sustain algal blooms. Phytoplankton draw down carbon dioxide from the atmosphere and in shelf seas can lock this carbon up in the sediments. In this project we will investigate the idea that the seasonal supply of nutrients to shelf seas is controlled by physical mixing processes at the shelf edge. This will be carried out using new sensors capable of determining nitrate and phosphate in-situ which will be deployed on underwater gliders for up to 3 weeks at a time. Underwater gliders are autonomous vehicles that, after launching from close to the coast, can "fly" to a sampling site and send back data via a satellite link. We will use four glider missions over a seasonal timescale (June & Sept 2013, Jan & April 2014) in order to gain a fundamental insight into the annual supply of nutrients to the highly productive shelf seas around the Malin Shelf. Alongside the nutrient sensors on the gliders will be three other sensors, a conductivity and temperature sensor, an oxygen sensor and a sensor which can determine chlorophyll a which is used as a proxy for phytoplankton biomass in the water. For each mission we will use two gliders to simultaneously characterise both the on- and off-shelf concentration gradients. These glider missions will be integrated into a large NERC-funded consortium, FASTNEt, which aims to identify the physical processes that facilitate the exchange of water across the edge of the north-west European shelf and understand how they evolve across the seasons. FASTNEt will be deploying long-term, shelf-edge current meter moorings and another underwater autonomous vehicle, the Autosub Long Range (ALR) in the same location. The use of sensors deployed on gliders allow us to increase the spatial and temporal coverage of data that would not be possible from traditional shipboard measurements, that cannot be carried out in stormy conditions. The combination of in-depth knowledge of the physical processes occurring at the Malin Shelf along with accurate high resolution nutrient data from the sensors means that we will be able to investigate what controls nutrient supply to the photic zone and how this impacts on the phytoplankton growth.Additionally, we will be trialling new deployment methodologies for these underwater gliders - using fast day-boats to take them as far offshore as possible from a coastal base.Our data will be freely available and we will share our findings with end-users (such as the UK government's Department for Environment, Food and Rural Affairs who are responsible for fisheries, and the UK Met Office) throughout the project.