雪卡毒素由小型底栖甲藻冈比亚藻产生，因常富集于珊瑚礁鱼类体内引发人类中毒事件而备受关注。明确不同海域冈比亚藻的种类组成、产毒规律及其食物链传递特征，是保障珊瑚礁海域水产品安全的关键。本项目拟以雪卡毒素问题突出的热带北缘典型珊瑚礁海域——北海涠洲岛为研究对象，构建分类单位明确的冈比亚藻纯培养品系，运用细胞毒性法和HPLC-MS/MS，研究冈比亚藻产毒特点和该海域无脊椎动物与珊瑚礁鱼类的雪卡毒素染毒特征，明确两者的生物地理分布关系，进而遴选有毒冈比亚藻和易染毒珊瑚礁生物，实验室模拟有毒冈比亚藻→无脊椎动物和草食性鱼类→肉食性鱼类食物链染毒途径，通过分析各营养级生物体内雪卡毒素动态含量和组成及转录组基因差异表达特点，阐明雪卡毒素食物链传递与代谢特征。结果有望拓展我们对雪卡毒素食物链研究的认识，并为我国南海海域水产品食用安全管理提供重要科学依据。

Benthic dinoflagellates in the genus Gambierdiscus spp. produce the ciguatoxin precursors responsible for the occurrence of ciguatera, a serious poisoning syndrome prevalent in coral reef ecosystems. In the management of ciguatera intoxication associated with consumption of reef organisms, it is essential to clarify the species composition and toxin variability of co-occurring Gambierdiscus, and to understand how the ciguatoxins transfer and accumulate in the food chain. Weizhou Island, located in the northern margin of the tropical waters of China, has a typical reef ecosystem that can support Gambierdiscus growth. Previous studies have shown that reef fish in the region contain ciguatoxins far beyond the seafood safety threshold. Here, we will collect benthic Gambierdiscus cells, the most common invertebrates and reef fishes from Weizhou Island, establish Gambierdiscus cultures and characterize their taxonomic affinities at the species level through a combination of scanning electron microscopy and phylogenetic analysis. Using cell bioassay and HPLC-MS/MS, we will determine the toxicity of the individual isolates of Gambierdiscus as well as the invertebrates and reef fishes. Using laboratory experiments, the transfer of ciguatoxins from Gambierdiscus to invertebrate and herbivores, and further to carnivores will be simulated; ciguatoxin profiles, their overall toxin content, and differentially expressed genes by transcriptomics will also be analyzed in this process. This research is assumed to provide fundamental insights into the mechanisms of ciguatoxin transfer through the food chain in the northern margin of the tropical seawater of China. This is critical to understanding the origin, transfer, and fate of ciguatoxins in the region and necessaruy for the management of human ciguatera poisoning incidents in the South China Sea.