Hidden Diversity in Arctic Kelp Beds

• Main Author: Dankworth, Marie
• Format: Thesis
• Language: unknown
• Published: 2016
• Subjects: Arctic; Arctic Ocean; Sea ice; Spitsbergen
• Online Access: https://epic.awi.de/id/eprint/43195/; https://hdl.handle.net/10013/epic.49679

Marine macroalgae are important marine costal primary producers and play an important in roll in the Arctic ecosystem. The Arctic Ocean is going through an unprecedented change and the region has been getting warmer over the past few decades. Temperatures are forecast to increase at double the global rate during the 21stcentury. Increasing temperatures and de-creasing sea ice might have a large impact on the Arctic ecosystem. Besides the common Arctic kelp Laminaria digitata, recent studies recorded the occurrence of Saccharina nigripes around Spitsbergen. The type species Laminaria digitata is involved in taxonomic confusion based on the great morphological plasticity varying with its environment. Mucilage duct channels are a taxonomic feature for the differentiation between the species. In this study, a combination of molecular and morpho-anatomical tools determines whether mucilage duct channels are a useful taxonomic character for species differentiation in the genera Saccharina and Laminaria. Microscopic examination and DNA-Barcoding determine the presence of Saccharina nigripes at Hansneset and the use of mucilage duct channels in the stipe are useful for species distinc-tion. Only kelps with present mucilage duct channels in the stipe could be taxonomically de-termined as Saccharina nigripes. Laminaria digitata and Saccharina latissima lacked mucilage duct channels in the stipe, also Saccharina nigripes individuals located in upper layers were lacking mucilage duct channels in the stipe. Saccharina nigripes are mostly abundant at in the deeper layers, whereas Laminaria digitata in 2.5 m depth at Hansneset. Below water level, Saccharina nigripes (n=4) individuals were genetically identified. Furthermore, the proportion of mucilage duct channels in stipe of Saccharina nigripes increases significantly with depth.