Global rise of symbiotic plankton - an international network to investigate a growing threat to marine fisheries

地球上的生命严重依赖生活在海洋中的微小浮游生物。这些微小的浮游生物可以分为三种类型：(1)浮游植物：通过光合作用利用二氧化碳和太阳能量制造食物和氧气的微小“植物”；(2)原生浮游动物：以浮游植物为食的微小“动物”，反过来又是小鱼的食物；(3)混合浮游生物；结合“植物+动物”，进行光合作用（制造食物和释放氧气）以及捕食猎物的微生物。在这个项目中，我们将探索浮游生物夜luca的“生活方式”，通常被称为“海闪”，因为它们可以形成生物发光的花朵。夜光虫是单细胞的，直径1毫米。作为一种全球分布的世界性微生物，它们出现在所有大陆（南极洲除外）的海岸上，它们作为一种“动物”（原生浮游动物）存在，因其颜色而被称为红色夜luca。然而，另一种形式正在亚洲水域占据主导地位；这是一种“植物+动物”（混合浮游生物）的形式，被称为绿色夜luca，因为它含有数百个绿色浮游植物的细胞。绿夜luca仍然吃东西，但通过捕获和“寄主”浮游植物群落（这一过程被称为共生），它们也进行光合作用。绿夜luca通常只生活在温暖的热带水域。但随着气候变化，绿色夜莺正在蔓延。在过去的20年里，阿拉伯海和东南亚海域经常出现绿色夜莺的大量繁殖。红色夜莺会因食物耗尽而饿死，而绿色夜莺则会持续开花。由于它们不容易被食用，它们在海洋中的存在阻碍了鱼类的正常食物链。鱼类数量的减少和水母数量的增加，已经影响了1.4亿多依赖以前高产渔业的人的社会经济。水华还会阻塞海水淡化设施和炼油厂的取水口。人们担心的是，随着气候变化，在其他地区，绿色夜莺将开始与红色夜莺一起出现；随着气候变化，它可能会蔓延到欧洲水域、美国水域和中国东海——所有重要的渔业地区。这两种夜莺在热带水域开花的原因尚不清楚。同样，不知道是什么因素导致绿色夜莺比红色夜莺更流行，反之亦然。我们认为这种转变的关键在于夜luca捕获并维持共生的类植物浮游植物（原绿藻）。然而，人们对这些原绿藻知之甚少——它们发生在哪里，温度和光照如何影响它们的生长，因此，气候变化将如何影响它们在全球海洋中的传播。在这个项目中，我们将探索影响原绿藻细胞在自由生活和与绿色夜光藻共生时生长的因素。我们将采用在英国、美国和泰国开发的最先进的研究方法，汇集一支具有独特而互补技能的专家团队。除了科学出版物外，该项目的产出将包括任何人都可以自由获取和下载的关于夜光鱼的信息卡、解释夜光鱼生理的视频、沿海水域监测和政策管理人员的报告。然而，作为一个种子玉米项目，最重要的成果将是建立一个国际科学家小组，以应对真正的国际问题。在这个联合国海洋十年中，该项目及时地了解了影响夜luca传播的因素，从而开发了预测未来水华的工具和方法，并努力实现更健康和可持续的海洋。

Life on Earth is heavily dependent on microscopic plankton that live in our oceans. These microscopic plankton can be divided between 3 types:(1) phytoplankton: microscopic "plants" that make food and oxygen through photosynthesis by using carbon dioxide and energy from the sun(2) protozooplankton: microscopic "animals" that eat the phytoplankton and are in turn food for small fish(3) mixoplankton: microbes that combine "plant+animal", photosynthesising (making food and releasing oxygen) as well as eating preyIn this project we are going to explore the "lifestyle" of the plankton Noctiluca, commonly called "sea sparkle" as they can form bioluminescent blooms. Noctiluca are single-celled and 1 mm in diameter. As a globally distributed cosmopolitan microbe occurring along the coasts of all the continents (except Antarctica) they exist as an "animal" (protozooplankton), called red-Noctiluca because of their colouration. However, another form is becoming dominant in Asian waters; this is a "plant+animal" (mixoplankton) form, referred to as green-Noctiluca because it harbours hundreds of cells of a green phytoplankton. Green-Noctiluca still eats but, by capturing and "hosting" colonies of phytoplankton (a process termed symbiosis), they also photosynthesise. Green-Noctiluca is usually found only in the warm tropical waters. But with climate change the green-Noctiluca are spreading. Over the last 20 years there have been regular blooms of green-Noctiluca in the Arabian Sea and also off SE Asia. Unlike red Noctiluca, which starves to death on exhaustion of its food, green Noctiluca blooms persist. As they are not readily eaten, their presence in the oceans blocks the normal food chain to fish. The decline in fish populations and increase in jellyfish, has affected the socio-economics of over 140 million humans who depend on previously highly productive fisheries. Blooms can also block desalination facilities as well as oil refinery water intakes. The concern is that with climate change the green-Noctiluca will start appearing alongside the red-Noctiluca in other areas; it could potentially spread with climate change into European waters, US waters and East China Sea - all areas with important fisheries. The reason why both types of Noctiluca bloom in tropical waters is unknown. Also, not known are the factors that lead to the prevalence of the green-Noctiluca over the red-Noctiluca or vice versa. We propose that the key to this transition must lay with the plant-like phytoplankton (Protoeuglena) which the Noctiluca capture and maintain as symbionts. However, very little is known about these Protoeuglena - where they occur, how do temperature and light affect their growth and, therefore, how will climate change effect their spread in global oceans. In this project we will explore factors affecting the growth of the Protoeuglena cells when they are free-living versus when they are in symbiosis with the green-Noctiluca. We will use state-of-the-art research methodologies developed in the UK, USA and Thailand, bringing together a team of experts with unique but complimentary skills.Outputs from this project, in addition to scientific publications, will include information cards about the fascinating Noctiluca for anyone to freely access and download, videos explaining the physiology of Noctiluca, reports for coastal water monitoring and policy managers. As a seedcorn project, the most important output, however, will be the establishment of an international team of scientists to confront what is a truly international problem. In this UN Decade of the Ocean, this project is a timely effort to understand the factors that govern the spread of Noctiluca and therefore, to develop tools and methodologies to predict future blooms and strive towards healthier and sustainable oceans.