30 June 2020, Volume 31 Issue 2

    

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Foreword
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  Foreword for Special Issue (Vol 31 No 2): Emerging polar science and its global links

  Azizan Abu Samah, Yunus Shukor, Claudio Gómez-Fuentes, Ian Allison

  Advances in Polar Science. 2020, 31(2): 0-1.

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  This special issue of Advances in Polar Science contains seven selected papers that were presented at MISA8 and the two SCAR related workshops, Tropic Antarctic Tele-connection (TATE) and State of the Antarctic Ecosystem (AntEco), which were held at the Universiti Putra Malaysia from 18th to 20th of June 2019. It also includes an Editorial Opinion “Arctic Environmental Change Research and Antarctic Studies Have Mutual Benefits” that is related to the main theme of MISA8—Polar Regions in the Global Climate System.
  The seven MISA8 articles cover the fields of atmospheric and environmental sciences, and research on Antarctic micro-organisms. One article presents observations of surface ozone variations at the Great Wall Station, Antarctica during austral summer while another evaluates tropical-Antarctic connections of an explosive cyclone in southern Brazil based on rainfall isotope ratios and synoptic analysis. Two papers consider the effects of a changing environment on polar microalgae: the toxic impacts on microalgae of oxybenzone, an ultraviolet filter introduced into Antarctica in sunscreens; and the impact of warming temperatures on the physiological and photosynthetic performance of two polar Chlorella sp. The three remaining contributions cover further aspects of research on Antarctic microorganisms. These are on the efficacy of the bacterium Rhodococcus sp. for bioremediation of fuel spills that are also contaminated with heavy metals; the structure and function of the cold shock domain (CSD)-containing protein from a psychrophilic yeast, Glaciozyma antarctica; and the genome of an Antarctic thermophilic bacterium, Geobacillus sp.
Contents
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  Contents Vol. 31 No. 2 June 2020

  Assistant Editor

  Advances in Polar Science. 2020, 31(2): 0-0.

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  Contents Vol. 31 No. 2 June 2020
  Special Issue: Emerging polar science and its global links
  
  Foreword
  Opinion Editorial
  Arctic environmental change research and Antarctic studies have mutual benefits
  Outi MEINANDER
  
  Articles
  Surface ozone variations at the Great Wall Station, Antarctica during austral summer
  Justin SENTIAN, Franky HERMAN, Mohd Sharul MOHD NADZIR & Vivian Kong WAN YEE
  
  Tropical–Antarctic connections of an explosive cyclone in southern Brazil: rainfall stable isotope ratios and atmospheric analysis
  Pedro Amaral REIS, Francisco Eliseu AQUINO, Venisse SCHOSSLER, Ronaldo Torma BERNARDO & Jefferson Cardia SIMÕES
  
  Effects of the sunscreen ultraviolet filter, oxybenzone, on green microalgae
  Ming-Li TEOH, Nur Suhaida SANUSI, Ching-Yee WONG & John BEARDALL
  
  Effects of elevated temperatures on growth and photosynthetic performance of polar Chlorella
  Syazana ANUWAR, Ming-Li TEOH, Wei-Hsum YAP, Fong-Lee NG & Siew-Moi PHANG
  
  The growth of the Rhodococcus sp. on diesel fuel under the effect of heavy metals and different concentrations of zinc
  Eg Xiang KAI, Wan Lutfi WAN JOHARI, Syahir HABIB, Nur Adeela YASID, Siti Aqlima AHMAD & Mohd Yunus SHUKOR
  
  Structure and function of a novel cold regulated cold shock domain containing protein from an obligate psychrophilic yeast, Glaciozyma antarctica
  Jennifer CHARLES, Makdi MASNODDIN, Farhan NAZAIE & Nur Athirah YUSOF
  
  Genome of a thermophilic bacterium Geobacillus sp. TFV3 from Deception Island, Antarctica
  
  Xin Jie CHING, Chui Peng TEOH, Dexter J. H. LEE, Marcelo GONZÁLEZ-ARAVENA, Nazalan NAJIMUDIN, Yoke Kqueen CHEAH, Paris LAVIN & Clemente Michael Vui Ling WONG
  
  Cover picture : Great Wall Station where the surface ozone measurements were carried out (paper by Justin Sentian et al., page 92)
Opinion Editorial
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  Arctic environmental change research and Antarctic studies have mutual benefits

  Outi MEINANDER

  Advances in Polar Science. 2020, 31(2): 89-91. https://doi.org/10.13679/j.advps.2020.0003

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  Arctic environmental change research and Antarctic studies have mutual benefits for increasing understanding of climate and environmental change in the polar regions. Two examples of bipolar environmental research questions with mutual benefit are presented here. First, climate change and climatically significant cryospheric changes are introduced, and then the roles of albedo feedback mechanism and light absorbing impurities are discussed. Second, the challenge of polar stratospheric ozone depletion is discussed in connection with the increase in the harmful ultraviolet solar irradiance reaching the Earth.
  
  Citation: Meinander O. Arctic environmental change research and Antarctic studies have mutual benefits. Adv Polar Sci, 2020, 31 (2): 89-91, doi: 10.13679/j.advps.2020.0003
  
  Note: Queries and discussions on this article should be made by E-mail directly with the corresponding author.
Articles
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  Surface ozone variations at the Great Wall Station, Antarctica during austral summer

  Justin SENTIAN, Franky HERMAN, Mohd Sharul MOHD NADZIR, Vivian Kong WAN YEE

  Advances in Polar Science. 2020, 31(2): 92-102. https://doi.org/10.13679/j.advps.2020.0007

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  Surface ozone (O₃) is a secondary pollutant harmful to human health and a greenhouse gas which is one of the prime climate forcers. Due to the clean atmospheric environment of the Antarctic region and given the complexity of O₃ chemistry, the observation of surface O₃ variability in this region is necessary in the quest to better understand the potential sources and sink of polar surface O₃. In this paper, we highlighted our observations on O₃ variability at the Great Wall Station (GWS) during austral summer in December 2018 and January 2019. The continuous surface O₃ measurement at the GWS, Antarctica was carried out using the Ecotech Ozone analyzer. To understand the roles of the meteorological conditions on the temporal variations of O₃, meteorological data was obtained from the conventional auto-observational station at the GWS. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model was employed to investigate the air mass transport over the region. The observed austral summer surface O₃ concentrations at the GWS exhibited variability and were significantly lower than those previously observed at other permanent coastal stations in Antarctica. The surface ozone variability at the GWS was strongly influenced by the synoptic change of air mass origin although the roles of photochemistry production and destruction were still uncertain. Marine characteristics and stable surface O₃ characterized the air masses that reached the GWS. The unique characteristic of surface O₃ at the coastal site of GWS was emphasized by its synoptic air mass characteristics, which displayed a significant influence on surface O₃ variability. Air mass that traveled over the ocean with relatively shorter distance was linked to the lower O₃ level, whereby the marine transport of reactive bromine (Br) species was thought to play a significant role in the tropospheric chemistry that leads to O₃ destruction. Meanwhile, the diurnal variation indicated that the O₃ background concentration levels were not strongly associated with the local atmospheric conditions.
  
  
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  Tropical–Antarctic connections of an explosive cyclone in southern Brazil: rainfall stable isotope ratios and atmospheric analysis

  Pedro Amaral REIS, Francisco Eliseu AQUINO, Venisse SCHOSSLER, Ronaldo Torma BERNARDO, Jefferson Cardia SIMÕES

  Advances in Polar Science. 2020, 31(2): 103-111. https://doi.org/10.13679/j.advps.2019.0039

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  This study analyzes the stable isotopic ratio (δ¹⁸O) and the synoptic characteristics of a precipitation event that occurred in the southernmost state of Brazil, Rio Grande do Sul, a region sensitive to explosive cyclogenesis in years with enhanced tropic-pole interactions. The main objective was to evaluate the influence of tropical and Antarctic climate systems on the event. Cavity ring-down spectroscopy was used for the water isotopic analysis, and NCEP CFSv2 data were employed for the synoptic analysis of rainfall over a 48-h period. An Amazonian isotopic signature on precipitated water was identified. A strong, low-level meridional flow from the Amazon Basin, combined with the development of a frontal system, resulted in intense cyclogenesis that generated an explosive cyclone.
  
  
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  Effects of the sunscreen ultraviolet filter, oxybenzone, on green microalgae

  Ming-Li TEOH, Nur Suhaida SANUSI, Ching-Yee WONG​, John BEARDALL

  Advances in Polar Science. 2020, 31(2): 112-123. https://doi.org/10.13679/j.advps.2019.0041

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  Ultraviolet (UV) filters are widely used in sunscreen and personal care products due to their ability to give protection to our skin from UV radiation. Oxybenzone, commonly known as benzophenone-3, is one type of UV filter found as the active ingredient in many pharmaceutical products. Although oxybenzone has been extensively studied as an environmental toxicant in the ecosystem, little is known about its toxicity effects on microalgae. The effects of oxybenzone on growth (measured as OD620 nm, chl ɑ and carotenoids) and macromolecular composition of polar microalgae (Chlorella UMACC 400 and Chlorella UMACC 401) and temperate microalgae (Chlorella sp., Chlamydomonas reinhardtii, Scenedesmus quadricauda) were investigated. These microalgae were cultured in triplicate and exposed to different oxybenzone concentrations (0, 100, 200, 300 and 400 mg·L⁻¹), at 4 ℃ and 18 ℃ for polar and temperate species respectively, for 96 h. The oxybenzone concentrations used represent a range from environmental to extreme concentrations to understand the impact of this toxicant on microalgae. The results showed that the highest concentration of oxybenzone (300 and 400 mg·L⁻¹) had adverse effects on growth rate and biomass of these microalgae. However, exposure to oxybenzone concentrations ranging from 200 mg·L⁻¹ to 400 mg·L⁻¹ did not have significant effects on S. quadricauda growth. The exposure to oxybenzone at higher concentrations also led to changes in cell structure after 96 h. Generally, protein and carbohydrate content of all microalgae except S. quadricauda increased with increasing oxybenzone concentrations. Protein content increased significantly when cells were exposed to oxybenzone, though effects were greater in the polar species, suggesting that it could be one of the adaptive strategies that enabled these microalgae to tolerate oxybenzone. Further investigation is required to determine the effects of oxybenzone on other features of microalgal performance at relevant environmental concentrations.
  
  
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  Effects of elevated temperatures on growth and photosynthetic performance of polar Chlorella

  Syazana ANUWAR, Ming-Li TEOH, Wei-Hsum YAP, Fong-Lee NG, Siew-Moi PHANG

  Advances in Polar Science. 2020, 31(2): 124-131. https://doi.org/10.13679/j.advps.2019.0040

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  Global warming has been the subject of concern in today’s world with elevating temperature causing the melting of polar ice and increasing sea level. The aim of this study was to investigate the physiological and photosynthetic performance of two polar Chlorella, namely Chlorella UMACC 250 and Chlorella UMACC 234 to elevating temperatures as might be experienced under future warming scenarios. The cultures were exposed to three different temperatures of 4 ℃, 8 ℃ and 12 ℃. The growth and photosynthetic activity were determined every 2 d for a period of 10 d. At the end of the experiment, the cultures were harvested and analysed for biochemical composition. Both Chlorella strains were able to tolerate higher temperatures than their ambient temperature. The final pigments content showed an increasing trend with increased temperatures for both strains. The photosynthetic activities were measured using pulse-amplitude modulation (PAM) fluorometer. The photosynthetic parameters including maximum quantum efficiency (Fv/Fm), maximum relative electron transport rate (rETRmax), light harvesting efficiency and photoadaptive index (Ek) were derived from the rapid light curves (RLCs). Both Chlorella strains showed a slight decline in growth and photosynthetic activities at the initial part of the experiment. However, they showed the ability to recuperate with Chlorella UMACC 250 recovers better compared to Chlorella UMACC 234. Both Chlorella strains showed similar trend in their carbohydrate content at 12 ℃, while the protein content of Chlorella UMACC 234 decreased when exposed to increasing temperatures. The results indicated that polar Chlorella are able to survive at increased temperatures throughout the experiment.
  
  
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  The growth of the Rhodococcus sp. on diesel fuel under the effect of heavy metals and different concentrations of zinc

  Eg Xiang KAI, Wan Lutfi WAN JOHARI, Syahir HABIB, Nur Adeela YASID, Siti Aqlima AHMAD, Mohd Yunus SHUKOR

  Advances in Polar Science. 2020, 31(2): 132-136. https://doi.org/10.13679/j.advps.2019.0043

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  Co-contamination of diesel fuel and heavy metals can be challenging for microbial remediation due to the complex composition of the fuel and the inhibitory effect of heavy metals. There is an urgent need to study this interaction to improve the pollutant removal efficiency in the Polar Regions. The growth of an Antarctic bacterium, Rhodococcus sp. was studied by comparing the growth at the logarithmic phase under the effect of selected heavy metals (Pb, Cr, As, Cd, Cu, Zn, Ni, Hg and Co). The selected heavy metals inhibited the growth of the Rhodococcus sp. on diesel fuel in an order from highest to lowest of: Hg > Zn > Cd > Cu > Co > Ni > As > Pb > Cr. Growth on diesel fuel co-contaminated with Hg and Zn were 2.95% and 5.71%, respectively compared to the no-metal control. A further experiment with various Zn concentrations was conducted. The specific growth rate of Rhodococcus sp. co-contaminated with different concentrations of Zn showed a correlation coefficient (r) of 0.916, and was modelled with an exponential decay model. Additional investigation is needed to determine the effect of low concentration of Zn on hydrocarbon degradation. It is important to understand the relationships between microbes, hydrocarbons and heavy metals, especially in the Polar Regions because this interaction might be promising in treating hydrocarbon-polluted sites containing heavy metals. The data and results also provide baseline tools of bioremediation processes at low temperatures and the knowledge of the ecological roles of Rhodococcus sp. in Antarctica.
  
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  Structure and function of a novel cold regulated cold shock domain containing protein from an obligate psychrophilic yeast, Glaciozyma antarctica

  Jennifer CHARLES, Makdi MASNODDIN, Farhan NAZAIE, Nur Athirah YUSOF

  Advances in Polar Science. 2020, 31(2): 137-145. https://doi.org/10.13679/j.advps.2019.0030

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  Cold shock domain (CSD)-containing proteins are one of the groups of the evolutionarily conserved nucleic acid-binding proteins in all three domains of life consisting of an ancient beta-barrel fold that serves to bind nucleic acids. The cDNA of a novel protein-coding gene containing CSD was cloned from Glaciozyma antarctica designated as Ga16676. The full length of Ga16676 gene with the size of 1335 bp encodes for an N-terminal CSD with conserved nucleic acids binding motif RNP1 and RNP2. The Ga16676 gene was cloned in pET30 Ek/LIC, sequenced, expressed and its resistance towards cold was characterized. Recombinant protein expression of Ga16676 showed overexpressed soluble expression in both supernatant and pellet forms at 20 ℃. The effects of recombinant CSD protein overexpression on colony formation shows that E. coli cells were able to grow at 37 ℃ and 20 ℃ but not at 4 ℃ while E. coli_Ga16676 cells were able to grow at all temperatures tested. In addition, E. coli_Ga16676 cells showed higher growth rate compared to empty E. coli cells at 10 ℃. Structural analysis of Ga16676 reveals some interesting findings such as more aromatic interactions for efficient binding in low energy environment, a longer loop that may contribute to structural flexibility and clustering of charged amino acids on the protein surface that is important for protein stability and flexibility.
  
  
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  Genome of a thermophilic bacterium Geobacillus sp. TFV3 from Deception Island, Antarctica

  Xin Jie CHING, Chui Peng TEOH, Dexter J. H. LEE, Marcelo GONZÁLEZ-ARAVENA, Nazalan NAJIMUDIN, Yoke Kqueen CHEAH, Paris LAVIN, Clemente Michael Vui Ling WONG

  Advances in Polar Science. 2020, 31(2): 146-152. https://doi.org/10.13679/j.advps.2019.0033

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  Thermophilic microorganisms have always been an important part of the ecosystem, particularly in a hot environment, as they play a key role in nutrient recycling at high temperatures where most microorganisms cannot cope. While most of the thermophiles are archaea, thermophiles can also be found among some species of bacteria. These bacteria are very useful in the fundamental study of heat adaptation, and they are also important as potential sources of thermostable enzymes and metabolites. Recently, we have isolated a Gram-positive thermophilic bacterium, Geobacillus sp. TFV3 from a volcanic soil sample from Deception Island, Antarctica. This project was undertaken to analyze the genes of this thermophilic Antarctic bacterium and to determine the presence of thermal-stress adaptation proteins in its genome. The genome of Geobacillus sp. TFV3 was first purified, sequenced, assembled, and annotated. The complete genome was found to harbor genes encoding for useful thermal-stress adaptation proteins. The majority of these proteins were categorized under the family of molecular chaperone and heat shock protein. This genomic information could eventually provide insights on how the bacterium adapts itself towards high growth temperatures.