https://repository.kopri.re.kr/handle/201206/5297 2026-03-10T16:40:33Z 2026-03-10T16:40:33Z Choi, Seon-Bin Rhee, Sung-Keun Lee, Sang H. Park, Jisoo Hwang, Chung Yeon Park, Soo-Je Si, Ok-Ja Min, Ui-Gi Kim, So-Jeong Jung, Man-Young Kim, Jong-Geol https://repository.kopri.re.kr/handle/201206/6005 2022-03-24T07:11:22Z 2016-01-01T00:00:00Z

Title: Cultivation and biochemical characterization of heterotrophic bacteria associated with phytoplankton bloom in the Amundsen sea polynya, Antarctica Authors: Choi, Seon-Bin; Rhee, Sung-Keun; Lee, Sang H.; Park, Jisoo; Hwang, Chung Yeon; Park, Soo-Je; Si, Ok-Ja; Min, Ui-Gi; Kim, So-Jeong; Jung, Man-Young; Kim, Jong-Geol Abstract: Polynyas are a key ecosystem for carbon cycling in the Antarctic Ocean due to the intensive primary production. Most of the knowledge regarding the bacterioplankton community in the Antarctic Ocean that is responsible for re-mineralization of fixed carbon comes from metagenomic analyses. Here, the extinction-dilution method was used to obtain representative heterotrophs from a polynya in the Amundsen Sea, Antarctica, and their biochemical potential for carbon re-mineralization were assessed. All 23 strains have close relatives belonging to type strains within the following genera (number of strains;% 16S rRNA gene sequence similarity): Bizionia (4;497.8%), Leeuwenhoekiella (1;96.2%), Pseudoalteromonas (14;498.5%), Pseudomonas (1;99.4%) and Sulfitobacter (3;100%), which were also observed in 454 pyrosequencing-based analysis of 16S rRNA gene sequences of the polynya. Although sequence reads related to Polaribacter were the most common, Polaribacter strains could only be obtained from colonies cultured on agar plates. The strain of Leeuwenhoekiella showed a prominent ability in hydrolyzing diverse esters, amides, and glycosides while the strains of Pseudoalteromonas, Polaribacter, and Bizionia showed extracellular enzyme activities only on a narrow range of amides. The strains of Leeuwenhoekiella, Pseudoalteromonas, and Sulfitobacter utilized various labile carbon sources: carbohydrates, organic acids, amino acids, and peptides. The most frequent isolates, strains of Pseudoaltermonas, showed marked differences in terms of their potential to utilize different types of labile carbon sources, which may reflect high genomic diversity. The strains of Bizionia and Pseudomonas did not utilize carbohydrates. Unique biochemical properties associated with extracellular hydrolase activities and labile carbon utilization were revealed for dominant culturable heterotrophs which gives insights into their roles in active re-mineralization of fixed carbons in polynya.

2016-01-01T00:00:00Z Lee, Yung Mi Hong, Soon Gyu Lee, Hong Kum Kim, Eun Hye https://repository.kopri.re.kr/handle/201206/7297 2022-03-24T07:12:52Z 2014-01-01T00:00:00Z

Title: Biodiversity and physiological characteristics of Antarcticand Arctic lichens-associated bacteria Authors: Lee, Yung Mi; Hong, Soon Gyu; Lee, Hong Kum; Kim, Eun Hye Abstract: The diversity and physiological characteristics of culturable bacteria associated with lichens from different habitats of the Arctic and Antarctica were investigated. The 68 retrieved isolates could be grouped on the basis of their 16S rRNA gene sequences into 26 phylotypes affiliated with the phyla Actinobacteria, Bacteroidetes, Deinococcus- Thermus, and Firmicutes and with the classes Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. Isolates belonging to the Alphaproteobacteria were the most abundant, followed by those belonging to Actinobacteria, Betaproteobacteria, Gammaproteobacteria, Bacteroidetes, Firmicutes, and Deinococcus-Thermus. Phylogenetic analysis showed that approximately 21 % of the total isolates represented a potentially novel species or genus (B97 % sequence similarity). Strains belonging to the genera Sphingomonas, Frondihabitans, Hymenobacter, and Burkholderia were recovered from lichen samples from both geographic locations, implying common and important bacterial functions within lichens. Extracellular protease activities were detected in six isolates, affiliated with Burkholderia, Frondihabitans, Hymenobacter, Pseudomonas, and Rhodanobacter. Extracellular lipase activities were detected in 37 isolates of the genera Burkholderia, Deinococcus, Frondihabitans, Pseudomonas, Rhodanobacter, Sphingomonas, and Subtercola. This is the first report on the culturable bacterial diversity present within lichens from Arctic and Antarctica and the isolates described herein are valuable resources to decode the functional and ecological roles of bacteria within lichens. In addition, the low similarity (B97 %) of the recovered isolates to known species and their production of cold-active enzymes together suggest that lichens are noteworthy sources of novel bacterial strains for use in biotechnological applications.

2014-01-01T00:00:00Z Rhee, Tae Siek Kim, Young Nam Yang, Eun Jin Choi, Man Sik Kim, Meesun Kim, Sun Young Kwon, Young Shin https://repository.kopri.re.kr/handle/201206/7313 2022-03-24T07:11:35Z 2014-01-01T00:00:00Z

Title: Fragilariopsis kerguelensis response to iron enrichment regarding its growth, uptake of nutrients and trace metals, and changes in CO2, CH4, and N2O Authors: Rhee, Tae Siek; Kim, Young Nam; Yang, Eun Jin; Choi, Man Sik; Kim, Meesun; Kim, Sun Young; Kwon, Young Shin Abstract: We performed laboratory experiments to investigate the response of Fragilariopsis kerguelensis, a predominant diatom species in the Southern Ocean, to different concentrations of dissolved iron in the culture medium to assess changes in nutrients, trace metals, and greenhouse gases―CO2, CH4, and N2O―during growth. F. kerguelensis was cultured in standard f2+Si media contained in closed chambers at 2°C, which is a typical surface temperature of the Southern Ocean in summer, under continuous irradiation with ~44 ？mol photons m-2 s-1 for 8 days. The media contained 2.2 nM, 7.0 nM, and 10.6 nM of dissolved iron at inoculation. F. kerguelensis grew faster if the initial dissolved iron concentration was higher. Its production rate was ~40 cells mL-1 d-1 with an increase of 10-15 molar dissolved iron on a single cell basis. Fe and Mo were consumed faster than the growth rate at higher dissolved iron concentrations and Mn and Zn were consumed more slowly, although a clear trend was not evident due to large uncertainties. Nitrate consumption by single cells increased with an increase of dissolved iron in the media, but phosphate and silicate showed a tendency to decrease. Hence, dissolved iron enhanced uptake of nitrate, but not the other nutrients, on a single cell basis. The carbon uptake per cell decreased with an increase in dissolved iron, which is opposite to the growth rate, suggesting that carbon content in single cells could not keep up with the cell growth. The iron efficacy of carbon uptake by single cells, defined as the ratio of the carbon uptake to the iron uptake, also showed a significant reduction with an increase in dissolved iron. This implies the inefficient usage of iron to absorb carbon at a high dissolved iron concentration. CH4 uptake by F. kerguelensis occurred in our experiments, but it was trivial in relation to the overall impact. N2O was consumed at a lower concentration of dissolved iron, but was emitted at a higher dissolved iron concentration, suggesting a facultative response of F. kerguelensis to the available dissolved iron.

2014-01-01T00:00:00Z Hahm, Doshick Lee, Sang H. Shin, Hyoung Chul Kim, Young Nam Park, Jisoo Kim, Hae-Cheol Rhee, Tae Siek https://repository.kopri.re.kr/handle/201206/6001 2022-03-24T07:11:21Z 2014-01-01T00:00:00Z

Title: Spatial and temporal variation of net community production and its regulating factors in the Amundsen Sea, Antarctica Authors: Hahm, Doshick; Lee, Sang H.; Shin, Hyoung Chul; Kim, Young Nam; Park, Jisoo; Kim, Hae-Cheol; Rhee, Tae Siek Abstract: We observed DO2/Ar in the surface waters of the Amundsen Sea, Antarctica, during the austral summers in 2011 and 2012 to investigate the variability of net community production (NCP). Corresponding to the typical peak phytoplankton bloom period, the DO2/Ar of the Amundsen Sea Polynya (ASP) reached 30% in early January 2011 and had a strong positive correlation with the sea surface temperature (SST) and chlorophyll-a (Chl-a). In contrast, DO2/Ar decreased to 210% in the sea ice zone (SIZ), which was likely asso- ciated with either net O2 consumption in the unlit area or the entrainment of deep water containing low dissolved oxygen. Near the terminal stage of the phytoplankton bloom in late February 2012, we observed the same contrasting DO2/Ar features between the ASP and SIZ. However, the DO2/Ar in the ASP was not >10%, which corresponded with the overall reduction in Chl-a, solar radiation, and SST compared with the corresponding values in 2011. The average net community production in the ASP was 119 6 79 mmol O2 m22 d21 in January 2011, and 23 6 14 mmol O2 m22 d21 in February 2012. The strong correlations of NCP with SST and mixed layer depth (MLD) indicate that the ASP phytoplankton bloom is likely initiated by a combination of increased light availability and SST in early summer. Low SST and variable fluorescence to maximum florescence ratio (Fv/Fm) in February indicate that decreased solar radiation and Fe availability are likely responsible for the phytoplankton bloom demise.

2014-01-01T00:00:00Z