PhytoMOPS: Phytoplankton Morphology and Optical Properties Sensor

藻类几乎存在于地球表面的每一处水体中。这些微生物产生了地球上大约一半的氧气，对地球上的生命至关重要。然而，当当地环境变化时，藻类也会对其生态系统、人类健康和水产养殖种群造成重大而昂贵的损害，并促进大量藻类的快速生长，即所谓的水华。营养物质的浓度、温度、光照条件以及人类或其他物种的有意或无意干预等因素都会影响藻类物种的动态，并导致有害藻华的形成。在水产养殖方面，赤潮对健康和经济构成重大危害。食用受产毒藻类大量繁殖影响的贝类可能会引起严重的人类健康问题。这些水华还通过水产养殖种群死亡以及由于当地藻类流行而暂时关闭场地和禁止捕捞，对水产养殖造成负面经济影响。据报道，世界各地都有养殖鱼类因藻类水华而大规模死亡的报道，每一次大事件的经济损失可能高达数千万英镑。几十年来，英国一直在以各种形式监测浮游植物及其产生的毒素，但人工采样和随后的非现场分析可能很难确定即将出现或迅速变化的问题所在的地区。显微镜是进行藻类计数的现行标准，它需要训练有素的采集人员，特别是分析人员，而且由于需要保存样本并将其运送到分析设施，这会造成必要的延误。该项目的总体目标是开发新技术，通过降低实时监测藻类生长的成本来减少赤潮造成的经济损失和健康风险。这项技术将通过提供低成本、高分辨率的独立数据来补充和解决现有监测技术的不足。PhytoMOPS技术是基于之前的实验室研究，证明可以使用精心设计的微流控通道和低成本的光学读取器来对藻细胞进行分类、计数和分类。这种被称为“惯性微流体”的分选技术依赖于精心设计的通道几何形状和流速，根据形状和大小对细胞进行分选。在本项目中，我们将在细胞分选区之后设计一个新的光学测量部分，在该部分中，根据微藻细胞的大小、形状和光吸收特性对其进行计数和分类。这项技术最初将在实验室建立和评估，结果将用于开发解释数据的分析方法。为了能够直接在水中进行测量，我们将采用国家海洋学中心(NOC)的水化学传感器平台，该平台已经用于在各种恶劣和难以进入的环境中进行长期自主测量。我们将把精心设计的NOC平台(包括微流控芯片、泵、阀门和控制/通信电子设备)与藻类分类技术相结合，生产出一个可部署的系统，能够作为独立的、低成本、低功耗的藻类物种动态监测器，用于赤潮形成的早期预警。最后，该项目包括系统的初步现场测试。部署将得到两个积极的HAB监测组织的推动，这两个组织也在整个项目中提供专家建议：苏格兰海洋科学协会和农业-食品生物科学研究所(北爱尔兰)。该系统将直接与人工采样和现有的藻类监测技术进行比较，并将评估其技术适用性、可用性和长期潜力。

Algae are present in nearly every body of water on the surface of the earth. These microscopic organisms produce roughly half of the oxygen on earth, and are vital to life on the planet. However, algae can also cause significant and expensive damage to their ecosystem, to human health, and to aquaculture stocks when the local environment changes and promotes the rapid growth of a large mass of algae, known as a bloom. Factors such as the concentration of nutrients, temperature, light conditions, and intentional or unintentional interventions by humans or other species all affect the dynamics of algae species and lead to the formation of harmful algal blooms (HABs). In the aquaculture context, HABs present a major health and economic hazard. Severe human health problems can arise from the consumption of shellfish which have been impacted by blooms of toxin-producing algae. These blooms also cause negative economic impacts on aquaculture through aquaculture stock mortality and through temporary site closures and bans on harvesting due to local algae prevalence. Large-scale mortalities of cultured fish due to algae blooms have been reported across the world and financial losses per large episode can range into the tens of millions of pounds. Monitoring of phytoplankton and of the toxins they produce has been undertaken in various forms in the UK for some decades but manual sampling and subsequent off-site analysis can be slow to identify areas with upcoming or rapidly-changing problems. Microscopy, the current standard for performing algae counts, requires trained personnel both in collection and particularly in analysis, and imposes a necessary delay as samples need to be preserved and transported to an analytical facility. The overall objective of this project is to develop new technology to decrease the economic losses and health risks caused by HABs by decreasing the costs of monitoring algae growth in real-time. This technology will complement and address shortcomings in existing monitoring techniques by providing low-cost, high resolution independent data. The PhytoMOPS technology is based on previous lab-based research demonstrating that algal cells could be sorted, counted, and classified using carefully-designed microfluidic channels combined with low-cost optical readouts. The sorting technique, known as "inertial microfluidics", relies on a carefully-designed channel geometry and flow rate to sort cells by shape and size. In this project, we will design a novel optical measurement section after the cell sorting region, in which the microalgal cells are counted and classfied according to their size, shape, and optical absorption properties. The technology will initially be built and evaluated in the lab where the results will be used to develop analytical methods for interpreting the data. In order to be able to make measurements directly in the water, we will adapt the National Oceanography Centre's (NOC's) water chemistry sensor platform which has already been used for long-term autonomous measurements in a wide range of harsh and inaccessible environments. We will combine the well-engineering NOC platform (including microfluidic chips, pumps, valves, and control/communication electronics) with the algae sorting technology to produce a deployable system capable of acting as a standalone, low-cost, low-power monitor of algal species dynamics for early warning of HABS formation. Lastly, this project involves initial field tests of the system. The deployments will be facilitated by two active HAB monitoring organisations who are also providing expert advice throughout the project: the Scottish Assocation for Marine Science and the Agri-Food Bioscience Institute (North Ireland). The system will will be compared directly against manual sampling and existing algal monitoring technology and will be be evaluated for its technical suitability, usability, and long-term potential.