https://repository.kopri.re.kr/handle/201206/11552 Wed, 11 Mar 2026 19:12:53 GMT 2026-03-11T19:12:53Z https://repository.kopri.re.kr/handle/201206/13713 Title: Seasonal Dietary Shifts of the Gammarid Amphipod Gondogeneia antarctica in a Rapidly Warming Fjord of the West Antarctic Peninsula Authors: Ahn, In-Young; Elias-Piera, Francyne; Ha, Sun-Yong; Rossi, Sergio; Kim, Dong-U Abstract: The amphipod Gondogeneia antarctica is among the most abundant benthic organisms, and a key food web species along the rapidly warming West Antarctic Peninsula (WAP). However, little is known about its trophic strategy for dealing with the extreme seasonality of Antarctic marine primary production. This study, using trophic markers, for the first time investigated seasonal dietary shifts of G. antarctica in a WAP fjord. We analyzed delta C-13 and delta N-15 in G. antarctica and its potential food sources. The isotopic signatures revealed a substantial contribution of red algae to the amphipod diet and also indicated a significant contribution of benthic diatoms. The isotope results were further supported by fatty acid (FA) analysis, which showed high similarities in FA composition (64% spring-summer, 58% fall-winter) between G. antarctica and the red algal species. G. antarctica delta C-13 showed a small shift seasonally (-18.9 to -21.4 & PTSTHOUSND;), suggesting that the main diets do not change much year-round. However, the relatively high delta N-15 values as for primary consumers indicated additional dietary sources such as animal parts. Interestingly, G. antarctica and its potential food sources were significantly enriched with delta N-15 during the fall-winter season, presumably through a degradation process, suggesting that G. antarctica consumes a substantial portion of its diets in the form of detritus. Overall, the results revealed that G. antarctica relies primarily on food sources derived from benthic primary producers throughout much of the year. Thus, G. antarctica is unlikely very affected by seasonal Antarctic primary production, and this strategy seems to have allowed them to adapt to shallow Antarctic nearshore waters. Wed, 01 Dec 2021 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/13713 2021-12-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/13037 Title: Patterns, drivers and implications of ascidian distributions in a rapidly deglaciating fjord, King George Island, West Antarctic Peninsula Authors: Kim, Dong-U; Khim, Jong Seong; Ahn, In-Young Abstract: We report strong evidence for the utility of ascidian communities as sentinel organisms for monitoring nearshore Antarctic marine ecosystem response to climate-induced warming and glacial melting. Ascidians are one of the most common Antarctic epibenthic megafauna, but information on their distribution and the determinants is still scarce. In this study we investigated spatial patterns of ascidians in Marian Cove (MC), a rapidly deglaciating fjord in the West Antarctic Peninsula, one of the most rapidly warming regions on earth. We also analyzed key drivers structuring the communities and assessed their relevance to glacial retreat and following processes. The first applied ROV survey in MC discovered that ascidians were the most diverse (14 out of 64 taxa) taxa with the greatest abundance (~264 inds·m-2). Ascidian abundance and diversity greatly varied in space, by distance from glacier and/or depths, explaining ~64% of total megafaunal variations. Notably, in deep seabed (50？90 m) they shifted distinctly from early colonization communities near glacier (0.2 km to glacier) with predominance of two opportunistic species, Molgula pedunculata and Cnemidocarpa verrucosa, to mature communities at the most remote site (3.5 km). A set of analyses revealed that such shifts were related mostly to changes in sediment properties that develop in association with glacial retreat and consequent processes. Sediment composition, grain size and sorting collectively explained outward increasing physical stability apparently with decreased influence of glacial retreat, supporting ascidian community maturing at the deep and distant site. BIOENV analysis indicated that “distance” to glacier is one key factor influencing ascidian community structure in the deep seabed. Overall, the results of the analyses strongly indicated that physical disturbances (mainly sedimentation and ice scouring) accompanying glacial retreat are an important force shaping ascidian assemblages in the cove, and that these forces are altered by the distance from the glacier and water depth. Notably, in this fjord, the period of sea bed deglaciation was roughly proportional to the distance to glacier over the last six decades. This suggested that the ascidian shift identified in this study reflects a long-term successional process associated with glacial retreat in the past in MC, which in turn warrants to project future changes in this glacial fjord and possibly other similar environments. Tue, 01 Jun 2021 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/13037 2021-06-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/11787 Title: Large Plastic Debris Dumps: New Biodiversity Hot Spots Emerging on the Deep-Sea Floor Authors: Song, Xikun; Lyu, Mingxin; Zhang, Xiaodi; Ruthensteiner, Bernhard; Ahn, In-Young; Guido, Pastorino; Yunan, Wang; Gu, Yifan; Ta, Kaiwen; Sun, Jie; Liu, Xi; Han, Jian; Ke, Caihuan; Peng, Xiaotong Abstract: Macroplastic debris recorded in the Mariana Trench and accumulated on some deep-sea canyons worldwide arouses great public concerns. Large plastic debris dumps found in canyons of the Xisha Trough, South China Sea become hotspots for deep-sea pollution, with one order of magnitude higher abundance than in other canyons. Here we adopted an integrative specimen-based approach to examine macroplastic items from large debris dumps in the Xisha Trough, and comparative items from continental shelves with rare macroplastics. On the investigated items, we found an epibenthic ecosystem with relatively high species diversity, comprised of 49 millimeter-sized fungi and invertebrate species dominated by scyphozoan polyps and brachiopod juveniles according to inhabiting density. These large dumps are functioning as new biodiversity hotspots hosting endemic species like soft corals or aplacophoran molluscs, providing a spawning habitat for gastropods and even specialized parasitic flatworms, and can be inferred as potential scattered regional sources releasing deep-sea coronate jellyfish. We hypothesize that macroplastics can boost population extension of sessile and some free-living (Mollusca) invertebrates and affect the deep-sea benthic-pelagic coupling process. The baseline of associated organisms needs to be set up and monitored in more canyons, where debris is transported to and accumulated at the highest density. Mon, 01 Feb 2021 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/11787 2021-02-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/11972 Title: Molecular-Level Chemical Characterization of Dissolved Organic Matter in the Ice Shelf Systems of King George Island, Antarctica Authors: Jang, Jiyi; Park, Jiyeon; Ahn, Seo-Hee; Park, Ki-Tae; Ha, Sun-Yong; Park, Jongkwan; Cho, Kyung Hwa Abstract: The Antarctic shelf systems plays an important role in organic matter circulation on Earth; hence, identifying the characteristics of dissolved organic matter (DOM) can be a good indicator for understanding its origin, as well as climate change. In this study, to identify the characteristics of DOM in the Antarctic shelf systems, surface water was collected from the open sea (OS) and Marian cove (Fjord; FJ). Although there were no differences in DOM characteristics between sampling sites in quantitative analyses, the DOM in surface water of each region seemed to be more affected by terrestrial than marine biological sources in optical and molecular properties. This finding indicates that the terrestrial DOM related to mosses based on the molecular properties results; high levels of lipid-like (3539%) and unsaturated hydrocarbon-like (UH; 2734%) in both the OS and FJ regions, and significantly higher tannin-like substance and condensed aromatic structures (CAS) in the FJ than the OS region. When comparing the FJ transect samples, those nearest to a glacier (FJ1; 0.93 km from the glacier) showed relatively low salinity, high dissolved organic carbon (DOC), and high chromophoric DOM (CDOM), indicating that terrestrial DOM (possibly produced by moss) inflow occurred with the runoff from the freshly melting land ice and glacier. However, no significant differences in molecular composition were detected, suggesting that terrestrial DOM introduced into the Antarctic shelf systems by melting land ice and glacier runoff could be a major source of DOM-rich seawater during austral fall, when low marine biological activity occurs. This study has a great significance as background data for DOM characteristics in the Antarctic shelf systems due to the enhanced biological activity during the austral summer. Mon, 01 Jun 2020 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/11972 2020-06-01T00:00:00Z