DSpace Collection:

The complete mitochondrial genome of the ice krillEuphausia crystallorophias Holt & Tattersall, 1906 (Euphausiacea, Euphausiidae), from the Ross Sea, Antarctica

Mon, 01 Apr 2024 00:00:00 GMT

Title: The complete mitochondrial genome of the ice krillEuphausia crystallorophias Holt & Tattersall, 1906 (Euphausiacea, Euphausiidae), from the Ross Sea, Antarctica Authors: Kim, Sung Hoon; Kim Taeho; Son, Wuju; Kim, Jeong-Hoon; La, Hyoung Sul Abstract: The mitogenome of Euphausia crystallorophias collected from the Ross Sea Region Marine Protected Area (RSR MPA) is described for the first time. The assembled mitogenome was 17,291 bp in length and consisted of two ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs), 13 protein-coding genes (PCGs), and noncoding regions, all of which were identical to those of other euphausiid species. The most common start codon for the 13 PCGs was ATG, and the most common termination codon was TAA. The overall G + C content was 33.2% in the heavy strand. Euphausia crystallorophias was sister to E. superba in the phylogenetic analysis. The mitogenome of E. crystallorophias provided significant DNA molecular data for further identification and phylogenetic analysis within the euphausiids.

Korea-Arctic Warming and Response of Ecosystem

Fri, 01 Dec 2023 00:00:00 GMT

Title: Korea-Arctic Warming and Response of Ecosystem Authors: Yang, Eun Jin

Measurement report: Summertime fluorescence characteristics of atmosphericwater-soluble organic carbon in the marine boundary layer of the westernArctic Ocean

Sun, 01 Jan 2023 00:00:00 GMT

Title: Measurement report: Summertime fluorescence characteristics of atmosphericwater-soluble organic carbon in the marine boundary layer of the westernArctic Ocean Authors: Jung, Jinyoung; Miyazaki Yuzo; Hur Jin; Lee Yun Kyung; 전미해; Lee, Youngju; Cho, Kyoung-Ho; Chung, Hyun Young; Kim, Kitae; Choi, Jung-Ok; Catherine Lalande; Kim, Joo-Hong; Choi, Taejin; Yoon, Young Jun; Yang, Eun Jin; Kang, Sung-Ho Abstract: Accelerated warming and a decline in sea ice coverage in the summertime Arctic Ocean can significantly affect the emissions of marine organic aerosols and biogenic volatile organic compounds. However, how these changes affect the characteristics of atmospheric water-soluble organic carbon (WSOC), which plays an important role in the climate system, remains unclear. Thus, to improve our understanding of WSOC characteristics in the rapidly changing Arctic Ocean, including its summertime fluorescence characteristics, we simultaneously measured atmospheric concentrations of ionic species and WSOC, a fluorescence excitation-emission matrix coupled with parallel factor (EEM-PARAFAC) analysis of WSOC, and marine biological parameters in surface seawaters of the western Arctic Ocean during the summer of 2016. WSOC was predominantly present as fine-mode aerosols (diameter <2.5 mu m, median = 92 %), with the mean concentration being higher in the coastal water areas (462 +/- 130 ngC m(-3)) than in the sea-ice-covered areas (242 +/- 88.4 ngCm(-3)). Moreover, the WSOC in the fine-mode aerosols was positively correlated with the methanesulfonic acid in the fine-mode aerosol samples collected over the sea-ice-covered areas (r = 0.88, p<0.01, n = 10), suggesting high rates of sea-air gas exchange and emissions of aerosol precursor gases due to sea ice retreat and increasingly available solar radiation during the Arctic summer. Two fluorescent components, humic-like C1 and protein-like C2, were identified by the PARAFAC modeling of fine-mode atmospheric WSOC. The two components varied regionally between coastal and sea-ice-covered areas, with low and high fluorescence intensities observed over the coastal areas and the sea-ice-covered areas, respectively. Further, the humification index of WSOC was correlated with the fluorescence intensity ratio of the humic-like C1 / protein-like C2 (r = 0.89, p<0.01) and the WSOC concentration in the fine-mode aerosols (r = 0.66, p<0.05), with the highest values observed in the coastal areas. Additionally, the WSOC concentration in the fine-mode aerosols was positively correlated with the fluorescence intensity ratio of the humic-like C1 = protein-like C2 (r = 0.77, p<0.01) but was negatively correlated with the biological index (r = -0.69, p<0.01). Overall, these results suggested that the WSOC in the fine-mode aerosols in the coastal areas showed a higher degree of polycondensation and higher aromaticity compared to that in the seaice-covered areas, where WSOC in the fine-mode aerosols was associated with relatively new, less oxygenated, and biologically derived secondary organic components. These findings can improve our understanding of the chemical and biological linkages of WSOC at the ocean-sea-ice-atmosphere interface.

Characterization and source of fluorescent dissolved organic matter in the Western Arctic Ocean: new insights from the 2019 summer study

Sun, 01 Jan 2023 00:00:00 GMT

Title: Characterization and source of fluorescent dissolved organic matter in the Western Arctic Ocean: new insights from the 2019 summer study Authors: 전미해; Jung, Jinyoung; Park Mi Ok; Cho, Kyoung-Ho; Lee, Youngju; Yang, Eun Jin; Kang, Sung-Ho Abstract: Increase in river discharge and seasonal primary production and decline in sea ice coverage in the Arctic Ocean in summer can significantly affect the distribution and composition of dissolved organic matter (DOM). This study aimed to enhance the current available knowledge about the impacts of environmental changes on the characteristics of DOM in the rapidly changing Arctic Ocean. Seawater samples were collected from the western Arctic Ocean during the summer of 2019 and analyzed for fluorescent DOM (FDOM), dissolved organic carbon (DOC), and stable oxygen isotope (& delta;O-18) content in conjunction with biophysical properties. We identified two humic-like (C1 and C2) and one protein-like (C3) components using fluorescence excitation-emission matrix coupled with parallel factor (EEM-PARAFAC) analysis. Remarkably high intensities of humic-like FDOM were found in the upper halocline layer (32 < salinity < 33.5 psu, at depths between 50-200 m) with high inorganic nutrient concentrations and low N* values, indicating that the humic-like FDOM was supplied from the shelf sediment. Furthermore, shoaling of the upper halocline layer brought high levels of humic-like FDOM to the euphotic zone, resulting in an increased probability of photodegradation of humic-like FDOM due to exposure to solar radiation in the surface layer. Tryptophan-like FDOM was positively correlated with river water fraction (f(river)) and riverine DOC but not with chlorophyll-a (Chl-a) and heterotrophic bacterial abundance, indicating river discharge as a potential additional source of tryptophan-like FDOM. The correlation coefficients between tryptophan-like FDOM and river water parameters (f(river) and riverine DOC) differed across the Chukchi Sea, Chukchi Borderland, and East Siberian Sea, implying that the influence of river discharge on tryptophan-like FDOM is region-dependent. An increase in river discharge in future might lead to a greater supply of tryptophan-like FDOM, impacting the dynamics of DOM cycling in the western Arctic Ocean.