Monitoring a large Sargassum bloom subject to a major volcanic eruption (MONISARG)

卫星观测显示，2021年4月初，大型藻类马尾藻大量繁殖，集中在小安的列斯群岛，与4月9日开始的圣文森特岛的一次重大火山喷发不谋而合。自2011年以来，马尾藻在夏季的几个月里在热带大西洋激增，在海滩上积累和分解，对该区域的沿海人口造成了后果，对健康和生计造成了损害。水华每年变化很大，通常随着盛行的风和洋流向西漂流穿过热带大西洋。尽管对马尾藻的研究迅速增长，但关于主要马尾藻水华事件的性质、范围、寿命、时间和驱动过程仍存在重大不确定性。这些马尾藻的流入没有受到持续的地面和远程联合监测运动的影响。第一次，英国研究人员与该地区的同事合作，准备实时监测大量涌入的马尾藻，这恰好是一次重大火山喷发的影响--这是一种出人意料的自然事件组合。根据一个典型的季节性预报系统，我们预计在2021年6月至8月期间，大量马尾藻将在整个加勒比海海岸线上海滩，这将促使我们开展运动，监测海上和沿海的水华，目标是巴巴多斯和牙买加周围的水域和海滩。我们特别计划开发和使用高分辨率卫星图像，以揭示马尾藻的范围，甚至到单个垫子的细节。为了在初夏确定这些马尾藻席子盛行的地方，我们将在巴巴多斯周围近海水域和牙买加以东部署GPS跟踪器，以跟踪它们在加勒比海和牙买加附近的移动情况。我们追踪器的轨迹数据将与全球漂流者方案的数据相辅相成，确定目前在该地区或正在接近该地区的几名漂流者。在巴巴多斯和牙买加东海岸已知有马尾藻聚集的选定海滩，我们的项目伙伴将利用无人机调查来补充现场采样，系统地监测马尾藻的范围和登陆情况。虽然我们不知道持续喷发的时间，也不知道马尾藻的生长或死亡可能会受到什么影响，但这是一个偶然的机会，可以在同时发生的极端事件期间监测海洋和沿海环境。

Satellite observations reveal development in early April 2021 of a substantial bloom of the macroalgae Sargassum, centred on the Lesser Antilles, coincident with a major volcanic eruption on the island of St Vincent, which began on 9 April. Since 2011, Sargassum has proliferated across the tropical Atlantic in summer months, of consequence for coastal populations through the region as it accumulates and decomposes on beaches, causing damage to health and livelihoods. Blooms are highly variable from year to year, generally drifting westward across the tropical Atlantic with prevailing winds and currents. Despite rapid growth in research on Sargassum, there remains significant uncertainty with regard to the nature, extent, longevity, timing, and driving processes of major Sargassum bloom events. These Sargassum influxes have not been subject to a continuous combined ground-based and remote monitoring campaign. For the first time, UK researchers working with colleagues in the region are ready to monitor in real time a large Sargassum influx that is coincidentally subject to a major volcanic eruption - an unexpected and remarkable combination of natural events. Based on a prototype seasonal forecast system, we anticipate that substantial quantities of the Sargassum will beach along coastlines throughout the Caribbean during June-August of 2021, motivating our campaign to monitor the bloom at sea and along coasts, targeting waters and beaches around Barbados and Jamaica. We specifically plan to develop and use high-resolution satellite images that can reveal the extent of Sargassum, down to the detail of individual mats. Identifying where these Sargassum mats are prevalent in early summer, we will then deploy GPS trackers in offshore waters around Barbados and to the east of Jamaica, to track their movement through the Caribbean and in the vicinity of Jamaica specifically. Trajectory data from our trackers will be complemented with data from the Global Drifter Programme, identifying several drifters that are currently in, or approaching, the region. At selected beaches on the east coasts of Barbados and Jamaica, where Sargassum is known to accumulate, our Project Partners will systematically monitor the extent and landing of Sargassum, using drone surveys to complement in situ sampling. While we do not know the duration of the ongoing eruption, and how the growth or mortality of Sargassum may be affected, this is a serendipitous opportunity to monitor marine and coastal environments during simultaneous extreme events.