Kelp holobiont responses to run-off in Billefjorden, Svalbard in August 2022

Kelps act as ecosystem engineers and foundation species, providing the food web basis for Arctic coastal, rocky shore ecosystems. Arctic fjords are undergoing large climatic changes, with the consequences of glacial and terrestrial run-off on kelp holobionts largely being unknown. We compared areas being influenced by either glacial or terrestrial run-off with a control area in Billefjorden, Svalbard in August 2022. Kelps were collected from three sampling stations (A-I) per area, with a plant rake (Plant rake 19.000, acc. to Sigurd Olsen, KC Denmark, Silkeborg, Denmark) on 5±2 m water depth. Silica-dried meristematic tissue was used for biochemical (pigment, antioxidant activity) analyses. The tissue above the meristem was rinsed with ultrapure water and freeze-dried, before elements were measured of homogenized, digested material with a triple quadrupole ICP-MS/MS system (Agilent 8800, Agilent Technologies; Tokyo, Japan). For microbial analyses, an area of 10×10 cm above the meristem was swabbed with a sterile cotton swab. The V4-V5 regions (515F: 5'-GTGCCAGCMGCCGCGGTAA-3' and 907R: 5'-CCGTCAATTCMTTTRAGTTT-3') of the bacterial 16S rRNA gene from DNA extracts were amplified and sequenced using the Illumina Nova platform (Shanghai Hanyu Biotech lab, Shanghai, China).

大型褐藻（Kelp）作为生态系统工程师与基础物种，为北极沿岸岩岸生态系统提供了食物网基础支撑。北极峡湾正经历剧烈的气候变化，目前冰川与陆地径流对褐藻共生体（holobiont）的影响尚属未知。本研究于2022年8月在斯瓦尔巴群岛比尔峡湾（Billefjorden）开展，对比了受冰川径流、陆地径流影响的区域与对照区域。每个区域设置3个采样站位（A至I），使用植物耙具（Plant rake 19.000，产自丹麦锡尔克堡Sigurd Olsen公司，KC Denmark）在水深5±2米处采集褐藻样本。取硅胶干燥的分生组织进行生化分析，涵盖色素含量与抗氧化活性检测。将分生组织上方的藻体组织用超纯水冲洗后冷冻干燥，对均质化且经消解的样品采用三重四极杆电感耦合等离子体质谱联用系统（triple quadrupole ICP-MS/MS，安捷伦8800型，安捷伦科技，日本东京）进行元素含量测定。微生物分析环节中，使用无菌棉拭子擦拭分生组织上方10×10 cm的藻体区域；从DNA提取物中扩增细菌16S rRNA基因的V4-V5高变区，所用引物序列为515F：5'-GTGCCAGCMGCCGCGGTAA-3'与907R：5'-CCGTCAATTCMTTTRAGTTT-3'，随后通过Illumina Nova测序平台（中国上海汉禹生物科技实验室）完成测序。