Spectral Characterization of Dissolved Organic Matter in Seawater and Sediment Pore Water from the Arctic Fjords (West Svalbard) in Summer
Fjords in the high Arctic, as aquatic critical zones at the interface of land-ocean continuum, are undergoing rapid changes due to glacier retreat and climate warming. Yet, little is known about the biogeochemical processes in the Arctic fjords. We measured the nutrients and the optical properties o...
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| Format: | Article |
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MDPI AG
2021-01-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/13/2/202 |
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| author | Meilian Chen Ji-Hoon Kim Sungwook Hong Yun Kyung Lee Moo Hee Kang Young Keun Jin Jin Hur |
| author_facet | Meilian Chen Ji-Hoon Kim Sungwook Hong Yun Kyung Lee Moo Hee Kang Young Keun Jin Jin Hur |
| author_sort | Meilian Chen |
| collection | DOAJ |
| description | Fjords in the high Arctic, as aquatic critical zones at the interface of land-ocean continuum, are undergoing rapid changes due to glacier retreat and climate warming. Yet, little is known about the biogeochemical processes in the Arctic fjords. We measured the nutrients and the optical properties of dissolved organic matter (DOM) in both seawater and sediment pore water, along with the remote sensing data of the ocean surface, from three West Svalbard fjords. A cross-fjord comparison of fluorescence fingerprints together with downcore trends of salinity, Cl<sup>−</sup>, and PO<sub>4</sub><sup>3−</sup> revealed higher impact of terrestrial inputs (fluorescence index: ~1.2–1.5 in seawaters) and glaciofluvial runoffs (salinity: ~31.4 ± 2.4 psu in pore waters) to the southern fjord of Hornsund as compared to the northern fjords of Isfjorden and Van Mijenfjorden, tallying with heavier annual runoff to the southern fjord of Hornsund. Extremely high levels of protein-like fluorescence (up to ~4.5 RU) were observed at the partially sea ice-covered fjords in summer, in line with near-ubiquity ice-edge blooms observed in the Arctic. The results reflect an ongoing or post-phytoplankton bloom, which is also supported by the higher levels of chlorophyll <i>a</i> fluorescence at the ocean surface, the very high apparent oxygen utilization through the water column, and the nutrient drawdown at the ocean surface. Meanwhile, a characteristic elongated fluorescence fingerprint was observed in the fjords, presumably produced by ice-edge blooms in the Arctic ecosystems. Furthermore, alkalinity and the humic-like peaks showed a general downcore accumulation trend, which implies the production of humic-like DOM via a biological pathway also in the glaciomarine sediments from the Arctic fjords. |
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| language | English |
| last_indexed | 2024-03-09T04:36:34Z |
| publishDate | 2021-01-01 |
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| series | Water |
| spelling | doaj.art-1a72655ef36a44e78cff9a661602f77a2023-12-03T13:27:29ZengMDPI AGWater2073-44412021-01-0113220210.3390/w13020202Spectral Characterization of Dissolved Organic Matter in Seawater and Sediment Pore Water from the Arctic Fjords (West Svalbard) in SummerMeilian Chen0Ji-Hoon Kim1Sungwook Hong2Yun Kyung Lee3Moo Hee Kang4Young Keun Jin5Jin Hur6Department of Environment & Energy, Sejong University, Seoul 05006, KoreaPetroleum and Marine Research Division, Korea Institute of Geoscience and Mineral Resources, 124 Gwahak-ro, Yuseong-gu, Daejeon 34132, KoreaDepartment of Environment & Energy, Sejong University, Seoul 05006, KoreaDepartment of Environment & Energy, Sejong University, Seoul 05006, KoreaClimate Change Mitigation and Sustainability Division, Korea Institute of Geoscience and Mineral Resources, 124 Gwahak-ro, Yuseong-gu, Daejeon 34132, KoreaKorea Polar Research Institute (KOPRI), Incheon 21990, KoreaDepartment of Environment & Energy, Sejong University, Seoul 05006, KoreaFjords in the high Arctic, as aquatic critical zones at the interface of land-ocean continuum, are undergoing rapid changes due to glacier retreat and climate warming. Yet, little is known about the biogeochemical processes in the Arctic fjords. We measured the nutrients and the optical properties of dissolved organic matter (DOM) in both seawater and sediment pore water, along with the remote sensing data of the ocean surface, from three West Svalbard fjords. A cross-fjord comparison of fluorescence fingerprints together with downcore trends of salinity, Cl<sup>−</sup>, and PO<sub>4</sub><sup>3−</sup> revealed higher impact of terrestrial inputs (fluorescence index: ~1.2–1.5 in seawaters) and glaciofluvial runoffs (salinity: ~31.4 ± 2.4 psu in pore waters) to the southern fjord of Hornsund as compared to the northern fjords of Isfjorden and Van Mijenfjorden, tallying with heavier annual runoff to the southern fjord of Hornsund. Extremely high levels of protein-like fluorescence (up to ~4.5 RU) were observed at the partially sea ice-covered fjords in summer, in line with near-ubiquity ice-edge blooms observed in the Arctic. The results reflect an ongoing or post-phytoplankton bloom, which is also supported by the higher levels of chlorophyll <i>a</i> fluorescence at the ocean surface, the very high apparent oxygen utilization through the water column, and the nutrient drawdown at the ocean surface. Meanwhile, a characteristic elongated fluorescence fingerprint was observed in the fjords, presumably produced by ice-edge blooms in the Arctic ecosystems. Furthermore, alkalinity and the humic-like peaks showed a general downcore accumulation trend, which implies the production of humic-like DOM via a biological pathway also in the glaciomarine sediments from the Arctic fjords.https://www.mdpi.com/2073-4441/13/2/202dissolved organic matterexcitation emission matrixglaciofluvial runoffice algal bloomArctic glaciomarine sediment |
| spellingShingle | Meilian Chen Ji-Hoon Kim Sungwook Hong Yun Kyung Lee Moo Hee Kang Young Keun Jin Jin Hur Spectral Characterization of Dissolved Organic Matter in Seawater and Sediment Pore Water from the Arctic Fjords (West Svalbard) in Summer Water dissolved organic matter excitation emission matrix glaciofluvial runoff ice algal bloom Arctic glaciomarine sediment |
| title | Spectral Characterization of Dissolved Organic Matter in Seawater and Sediment Pore Water from the Arctic Fjords (West Svalbard) in Summer |
| title_full | Spectral Characterization of Dissolved Organic Matter in Seawater and Sediment Pore Water from the Arctic Fjords (West Svalbard) in Summer |
| title_fullStr | Spectral Characterization of Dissolved Organic Matter in Seawater and Sediment Pore Water from the Arctic Fjords (West Svalbard) in Summer |
| title_full_unstemmed | Spectral Characterization of Dissolved Organic Matter in Seawater and Sediment Pore Water from the Arctic Fjords (West Svalbard) in Summer |
| title_short | Spectral Characterization of Dissolved Organic Matter in Seawater and Sediment Pore Water from the Arctic Fjords (West Svalbard) in Summer |
| title_sort | spectral characterization of dissolved organic matter in seawater and sediment pore water from the arctic fjords west svalbard in summer |
| topic | dissolved organic matter excitation emission matrix glaciofluvial runoff ice algal bloom Arctic glaciomarine sediment |
| url | https://www.mdpi.com/2073-4441/13/2/202 |
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