Kim Dahae, Kim Jung-Hyun, Ahn Youngkyu, Jang Kwangchul, Jung Ji Young, Bae Minji, Nam Seung-Il
Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, South Korea.
Department of Marine Science and Convergence Technology, Hanyang University ERICA Campus, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan-si, Gyeonggi-do, 15588, South Korea.
Sci Rep. 2023 Oct 20;13(1):17935. doi: 10.1038/s41598-023-45141-z.
Svalbard fjords are recognized as hotspots for organic carbon (OC) burial and storage due to their high sedimentation rates, which effectively trap terrestrial sediments and inhibit extensive OC remineralization. In this study, we investigated surface sediments (n = 48) from eight Svalbard fjords, along with bedrock (n = 17), soil (n = 28), and plant (n = 12) samples, to identify the sources of sedimentary OC in these fjords using geochemical parameters. All examined surface sediments from the fjords showed a depletion in C (- 666.9 ± 240.3‰), indicating that recently fixed terrestrial and marine biomass alone cannot account for the entire sedimentary OC pool. Conventional bulk indicators such as N/TOC ratio and δC were insufficient for fully determining the sources of sedimentary OC. Therefore, we employed a four-end-member approach, using ΔC, δC, and lignin phenols to assess the relative contributions of petrogenic, soil-derived, plant-derived, and marine OC to the sedimentary OC pool. The analyzed fjord sediments consisted, on average, of 59.0 ± 28.1% petrogenic OC, 16.8 ± 12.1% soil-derived OC, 2.5 ± 2.2% plant-derived OC, and 21.8 ± 18.5% marine OC. This approach highlights the substantial contributions of petrogenic and aged soil-derived OC to present-day sedimentary OC in Svalbard fjords. Considering predicted global warming, accelerated inputs of petrogenic and soil-derived OC into fjords due to rapid glacier retreat may significantly impact the active carbon cycle and potentially contribute to CO emissions to the atmosphere, depending on burial efficiency.
斯瓦尔巴德群岛的峡湾因其高沉积速率而被认为是有机碳（OC）埋藏和储存的热点地区，高沉积速率有效地捕获了陆地沉积物并抑制了大量OC的再矿化。在本研究中，我们调查了斯瓦尔巴德群岛八个峡湾的表层沉积物（n = 48），以及基岩（n = 17）、土壤（n = 28）和植物（n = 12）样本，以利用地球化学参数确定这些峡湾中沉积OC的来源。所有检查的峡湾表层沉积物均显示出碳含量的亏损（-666.9±240.3‰），这表明仅近期固定的陆地和海洋生物量无法解释整个沉积OC库。诸如N/TOC比和δC等传统的总量指标不足以完全确定沉积OC的来源。因此，我们采用了一种四端元方法，利用ΔC、δC和木质素酚来评估成岩、土壤源、植物源和海洋OC对沉积OC库的相对贡献。分析的峡湾沉积物平均由59.0±28.1%的成岩OC、16.8±12.1%的土壤源OC、2.5±2.2%的植物源OC和21.8±18.5%的海洋OC组成。这种方法突出了成岩和老化土壤源OC对斯瓦尔巴德群岛峡湾当今沉积OC的重大贡献。考虑到预测的全球变暖，由于冰川快速退缩，成岩和土壤源OC向峡湾的加速输入可能会显著影响活跃的碳循环，并可能根据埋藏效率向大气中排放CO。
