Article
Multidisciplinary Sciences
P. A. Reid, R. A. Massom
Summary: Loss of protective sea-ice buffer in Antarctica has led to increased exposure of the coastal environment to open ocean and waves, which has significant effects on ice-shelf stability, coastal erosion, ice-ocean-atmosphere interactions, and shallow benthic ecosystems. Researchers have introduced a climate and environmental metric called Coastal Exposure Length, which measures the daily changes and variability in the length and occurrence of unprotected coastline in Antarctica. The study found that around 50% of Antarctica's 17,850-km coastline had no sea ice offshore each summer, with variations in exposure levels across regions and seasons. From 1979 to 2020, the annual maximum length of coastal exposure decreased by approximately 30 km per year.
NATURE COMMUNICATIONS
(2022)
Article
Environmental Sciences
Yue Cao, Xiawei Yu, Feng Ju, Haicong Zhan, Bei Jiang, Hui Kang, Zhouqing Xie
Summary: The bacterial community in Antarctic bioaerosols is dominated by Proteobacteria, showing low alpha-diversity but significant spatial and temporal variabilities. These bacteria are potentially transported from terrestrial, marine, and Antarctic polar sources through long-range transport and sea-air exchange pathways. The composition of bacterial community is significantly influenced by factors such as wind speed, temperature, and organic carbon, while bacterial richness and diversity do not differ significantly under different weather conditions.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Environmental Sciences
Claire L. Parkinson, Nicolo E. DiGirolamo
Summary: The satellite dataset spanning 42 years from 1979 to 2020 reveals recent losses in sea ice coverage in both the Arctic and Antarctic, with the Arctic experiencing record low sea ice extents while the Antarctic has seen record lows since 2015. The data also shows that globally, every calendar month has recorded a new monthly record low within the past 5 years, indicating a rapid decline in global sea ice coverage.
REMOTE SENSING OF ENVIRONMENT
(2021)
Review
Geochemistry & Geophysics
A. D. Fraser, P. Wongpan, P. J. Langhorne, A. R. Klekociuk, K. Kusahara, D. Lannuzel, R. A. Massom, K. M. Meiners, K. M. Swadling, D. P. Atwater, G. M. Brett, M. Corkill, L. A. Dalman, S. Fiddes, A. Granata, L. Guglielmo, P. Heil, G. H. Leonard, A. R. Mahoney, A. McMinn, P. van der Merwe, C. K. Weldrick, B. Wienecke
Summary: Antarctic landfast sea ice, also known as fast ice, is stationary sea ice that is attached to the coast, grounded icebergs, ice shelves, or other protrusions on the continental shelf. Despite its limited extent, fast ice plays a crucial role in various physical, biological, and biogeochemical processes, with both local and far-reaching consequences for the Earth system.
REVIEWS OF GEOPHYSICS
(2023)
Article
Environmental Sciences
Kazuya Kusahara
Summary: Recent observations have shown changes in the Antarctic sea ice and ice shelf over the years. Analysis from an ocean-sea ice-ice shelf model reveals a clear anti-correlation between Antarctic sea ice extent and ice shelf basal melting, indicating that the summer sea ice extent can act as a proxy for predicting Antarctic coastal water masses and ice shelf melting.
ENVIRONMENTAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Li-Juan Li, Chenshuo Lin, Xin-Rong Huang, Xin-Li An, Wen-Jing Li, Jian-Qiang Su, Yong-Guan Zhu
Summary: Protists play important roles in water environments and are known to host bacteria. However, their potential as reservoirs for human pathogens in wastewater treatment plants (WWTPs) has not been adequately examined. In this study, fluorescence-activated cell sorting and Illumina sequencing were used to investigate the dynamics of internalized bacterial communities in enriched protists from influents and effluents of five WWTPs. The results showed that Proteobacteria, especially Betaproteobacteria, dominated the intracellular bacterial communities of protists in both influents and effluents, accounting for 72.6% of the total bacterial communities. The most frequently detected genus differed between influents and effluents, with Sulfuricurvum prevalent in influent samples and Chryseobacterium and Pseudomonas in effluent samples. The effluents exhibited a more diverse and abundant intracellular bacterial community compared to the influents. Additionally, the potential intracellular bacterial pathogens were 26 times higher in effluents, with Pseudomonas fluorescens and Pseudomonas putida significantly enriched. This study provides insights into bacterial communities and potential pathogens harbored by protists in WWTPs, contributing to improved biosafety evaluation.
ENVIRONMENT INTERNATIONAL
(2023)
Article
Geosciences, Multidisciplinary
Wilton Aguiar, Sang-Ki Lee, Hosmay Lopez, Shenfu Dong, Helene Seroussi, Dani C. Jones, Adele K. Morrison
Summary: Melting of the ice sheet in the Southern Ocean has implications for the formation and properties of the Antarctic Bottom Water (AABW). Models have been used to examine the effects of different spatial distributions and magnitudes of meltwater fluxes on AABW. The study finds that a realistic and spatially varying meltwater flux can sustain AABW with higher salinities compared to uniform meltwater flux simulations. Furthermore, the increasing meltwater discharge from the Antarctic ice sheet can contribute to the observed freshening of AABW.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Meteorology & Atmospheric Sciences
Kazuya Kusahara, Hiroaki Tatebe, Tomohiro Hajima, Fuyuki Saito, Michio Kawamiya
Summary: Future atmospheric warming can result in enhanced basal melting of Antarctic ice shelves, caused by a combination of warm deep water intrusions and warm surface water formation. This melting will lead to irreversible changes in the Antarctic ice shelves and Southern Ocean climate.
JOURNAL OF CLIMATE
(2023)
Article
Biology
William S. Y. Wong, Lukas Hauer, Paul A. Cziko, Konrad Meister
Summary: The research finds that the Antarctic scallop Adamussium colbecki possesses a unique micro-ridge structure that allows it to control underwater ice formation, preventing dangerous accumulation and firm attachment of ice. This special structure helps protect the scallops from anchor ice and may be a key trait for their survival in anchor ice zones.
COMMUNICATIONS BIOLOGY
(2022)
Article
Oceanography
Daniel N. Goldberg, Andrew G. Twelves, Paul R. Holland, Martin G. Wearing
Summary: Little is known about Antarctic subglacial hydrology, but it is believed that subglacial runoff enhances submarine melt locally through buoyancy effects. This study examines the effects of runoff on sea ice and oceanography on the Continental Shelf, and finds that runoff enhances localized melt and reduces summer sea ice volume. Runoff-driven melt and circulation may be an important missing process in regional Antarctic ocean models.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Multidisciplinary Sciences
Chiara Leo, Francesco Nardi, Claudio Cucini, Francesco Frati, Peter Convey, James T. Weedon, Dick Roelofs, Antonio Carapelli
Summary: Collembola in Antarctica play a key role in soil biota globally, and their microbiomes can contribute to important metabolic functions. The diversity and richness of springtail microbiomes in Antarctica are lower compared to temperate regions, and the microbiome composition is predominantly species-specific with limited core microbiome shared across different species. Geographic origin is the prevalent driver in shaping the microbiomes of Antarctic springtails, with closer similarity between individuals from the same bioregion rather than those belonging to the same genus.
SCIENTIFIC REPORTS
(2021)
Article
Geosciences, Multidisciplinary
John Turner, Caroline Holmes, Thomas Caton Harrison, Tony Phillips, Babula Jena, Tylei Reeves-Francois, Ryan Fogt, Elizabeth R. Thomas, C. C. Bajish
Summary: On February 25, 2022, Antarctic sea ice extent reached a satellite-era record low level, and sea ice anomalies were observed in all sectors of the Southern Ocean, with the largest anomalies in the Ross and Weddell Seas.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Tian R. Tian, Alexander D. Fraser, Thomas Lavergne, Sonya L. Fiddes, Chen Zhao, Petra Heil
Summary: Sea ice kinematics has significant impacts on the global ocean-atmosphere system, affecting albedo, ice cover, heat transmission, and ice thickness distribution. A new ice motion product called S2S shows promise in representing ice drift trajectories, but its application in ice kinematics research is yet to be explored. This study investigates Antarctic sea ice differential kinematic parameters using the S2S ice motion product and compares them with parameters derived from daily maps. The results indicate a strong correlation between S2S-derived parameters and time scale, as well as a relationship with ice thickness, suggesting the potential for proxy measurements of ice thickness.
REMOTE SENSING OF ENVIRONMENT
(2023)
Article
Engineering, Marine
Felix Paul, Tommy Mielke, Carina Schwarz, Joerg Schroeder, Tokoloho Rampai, Sebastian Skatulla, Riesna R. Audh, Ehlke Hepworth, Marcello Vichi, Doru C. Lupascu
Summary: Frazil ice, the first ice forming in the annual cycle in the Marginal Ice Zone (MIZ) of the Antarctic, consists of loose disc-shaped ice crystals and plays a fundamental role in the freezing processes by forming the surface grease ice layer. The rheological properties of frazil ice, including shear thinning flow behavior, have a crucial influence on the growth of sea ice in the MIZ, and real-data-founded measurements enable modeling of the annual ice cycle.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Multidisciplinary Sciences
Lei Liang, Huadong Guo, Shuang Liang, Xichen Li, John C. Moore, Xinwu Li, Xiao Cheng, Wenjin Wu, Yan Liu, Annette Rinke, Gensuo Jia, Feifei Pan, Chen Gong
Summary: Antarctica's response to climate change varies greatly in location and time. Using a 43-year record, we found that both the start and end of the snowmelt season in Antarctica are being delayed. The delay in the melt season is caused by increased heat flux from the ocean to the atmosphere and is influenced by sea-ice variability. This delay in snowmelt season results in a decrease in surface solar radiation absorption.
NATIONAL SCIENCE REVIEW
(2023)
Article
Limnology
Anders Torstensson, Andrew R. Margolin, Gordon M. Showalter, Walker O. Smith, Elizabeth H. Shadwick, Shelly D. Carpenter, Francesco Bolinesi, Jody W. Deming
Summary: The study found that sea-ice microbial communities in the central Arctic Ocean are largely insensitive to elevated pCO(2) levels, with algae and bacteria growth unaffected. Concentrations of dissolved organic carbon (DOC) and extracellular polymeric substances (EPS) were also not impacted by shifts in the inorganic C/N balance resulting from CO2 enrichment.
LIMNOLOGY AND OCEANOGRAPHY
(2021)
Article
Biology
Ulrike Braeckman, Francesca Pasotti, Ralf Hoffmann, Susana Vazquez, Angela Wulff, Irene R. Schloss, Ulrike Falk, Dolores Deregibus, Nene Lefaible, Anders Torstensson, Adil Al-Handal, Frank Wenzhoefer, Ann Vanreusel
Summary: This study demonstrates how climate-related glacial melt disturbance shifts benthic communities from net autotrophy to heterotrophy. It sheds light on the potential impact of future glacial melt and run-off on the metabolic balance of Antarctic benthic communities.
COMMUNICATIONS BIOLOGY
(2021)
Article
Multidisciplinary Sciences
Subhendu Chakraborty, Ken H. Andersen, Andre W. Visser, Keisuke Inomura, Michael J. Follows, Lasse Riemann
Summary: The research developed a mathematical model for N2 fixation on sinking marine particles, showing that the fixation rate is determined by various factors inside the particles. The study suggests that heterotrophic N2 fixation plays a significant role in oceanic nitrogen cycling.
NATURE COMMUNICATIONS
(2021)
Article
Limnology
Soren Hallstrom, Mar Benavides, Ellen R. Salamon, Clayton W. Evans, Lindsey J. Potts, Julie Granger, Craig R. Tobias, Pia H. Moisander, Lasse Riemann
Summary: The composition of diazotrophic communities in Narragansett Bay is significantly correlated with the rates of pelagic N-2 fixation, which range from 0.02 to 9.41 nmol N L-1 d(-1). Factors such as temperature, salinity, and mean sea level also influence the fluctuations in diazotroph community composition.
LIMNOLOGY AND OCEANOGRAPHY
(2022)
Article
Environmental Sciences
Soren Hallstrom, Mar Benavides, Ellen R. Salamon, Javier Aristegui, Lasse Riemann
Summary: This study investigated the distribution of nitrogen fixation activity and diazotroph community across the Cape Verde Frontal Zone. The results showed variations in nitrogen fixation rates and community composition, with cyanobacteria dominating in both surface and aphotic waters. The findings also suggested the potential downward flux of metabolically active cyanobacteria and cross-frontal advection of cyanobacterial diazotrophs.
Article
Plant Sciences
Adil Y. Al-Handal, Anders Torstensson, Angela Wulff
Summary: Continuous observations of Antarctic benthic diatoms are essential for detecting changes in species composition and biodiversity due to environmental changes. This study provided a systematic list of benthic diatoms from Potter Cove in summer 2015, comparing new findings with observations from 2003. The dominant species remained the same over the 12-year period, but significant changes were observed in the presence of certain species.
Review
Microbiology
Lasse Riemann, Eyal Rahav, Uta Passow, Hans-Peter Grossart, Dirk de Beer, Isabell Klawonn, Meri Eichner, Mar Benavides, Edo Bar-Zeev
Summary: Diverse non-cyanobacterial diazotrophs (NCDs) are found in various aquatic ecosystems, primarily inhabiting aggregates and playing a significant role in nitrogen cycling.
FRONTIERS IN MICROBIOLOGY
(2022)
Article
Ecology
Soren Hallstrom, Jean-Baptiste Raina, Martin Ostrowski, Donovan H. Parks, Gene W. Tyson, Philip Hugenholtz, Roman Stocker, Justin R. Seymour, Lasse Riemann
Summary: Heterotrophic bacterial diazotrophs (HBDs) in the pelagic ocean can use chemotaxis to locate low-oxygen microenvironments suitable for nitrogen fixation, and their activity can influence marine nitrogen and carbon biogeochemistry.
Article
Ecology
Mar Benavides, Sophie Bonnet, Frederic A. C. Le Moigne, Gabrielle Armin, Keisuke Inomura, Soren Hallstrom, Lasse Riemann, Ilana Berman-Frank, Emilie Poletti, Marc Garel, Olivier Grosso, Karine Leblanc, Catherine Guigue, Marc Tedetti, Cecile Dupouy
Summary: The cyanobacteria Trichodesmium is capable of fixing N2 in the meso- and bathypelagic layers of the ocean. This activity contributes to the nutrient supply for organisms in the mesopelagic zone. The fixation rates of Trichodesmium are affected by hydrostatic pressure and temperature changes.
Article
Environmental Sciences
Alba Filella, Lasse Riemann, France Van Wambeke, Elvira Pulido-Villena, Angela Vogts, Sophie Bonnet, Olivier Grosso, Julia M. Diaz, Solange Duhamel, Mar Benavides
Summary: This study investigates the effect of P-anhydrides on diazotrophs in the ocean and finds that P-anhydrides can stimulate N-2 fixation in certain cyanobacteria under low phosphate concentrations. Moreover, the study also reveals that P-anhydrides can be used as an energy source by certain bacteria.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Marine & Freshwater Biology
Tina Liesirova, Tobias Aarenstrup-Launbjerg, Soren Hallstrom, Meriel J. Bittner, Lasse Riemann, Maren Voss
Summary: Nitrogen fixation by heterotrophic non-cyanobacterial diazotrophs is observed in marine deep-sea sediments. In this study, the researchers found that sediment-associated nitrogen fixation during resuspension is influenced by small-grained sediments, organic carbon content, and nutrient concentrations in pore waters. Sulfate reducing bacteria, such as Desulfo-bacterales and Desulfovibrionales, play a significant role in heterotrophic nitrogen fixation during resuspension.
ESTUARINE COASTAL AND SHELF SCIENCE
(2023)
Article
Ecology
A. Torstensson, G. M. Showalter, A. R. Margolin, E. H. Shadwick, J. W. Deming, W. O. Smith
Summary: We examined the distribution of biota and carbonate chemistry variables in Arctic sea ice during late summer and early autumn 2018. The sea ice sampled was thick and had low bulk salinities, with most variables increasing with depth. Our measurements indicated that detrital carbon was the main organic pool in the ice cores. Near the ice-water interface, autotrophic material comprised around 50% of the total particulate organic carbon. Nutrient availability in the under-ice water was limited, suggesting limited activity and biomass of sea-ice biota when autumn sea ice is thicker than 1 m.
MARINE ECOLOGY PROGRESS SERIES
(2023)
Article
Microbiology
Lisa W. von Friesen, Maria L. Paulsen, Oliver Muller, Friederike Grundger, Lasse Riemann
Summary: The Arctic Ocean is being significantly impacted by climate change, and the effect on primary productivity remains uncertain. Diazotrophs, which are capable of converting atmospheric nitrogen to ammonia, have been detected in the nitrogen-limited Arctic Ocean, but their distribution and community composition dynamics are not well understood. This study sequenced the diazotroph marker gene nifH from various regions in the Arctic Ocean and identified distinct regional communities. The study found that proteobacterial diazotrophs dominated all seasons and depths, while Cyanobacteria were only sporadically present in coastal and freshwaters. The composition and diversity of diazotrophs in the Arctic are influenced by glacial meltwater, seasonal activity, and the dominance of noncyanobacterial diazotrophs.
FEMS MICROBIOLOGY ECOLOGY
(2023)
Article
Biotechnology & Applied Microbiology
Victor Fernandez-Juarez, Soren Hallstrom, Cesar O. Pacherres, Jiaqi Wang, Guillem Coll-Garcia, Michael Kuhl, Lasse Riemann
Summary: This study examined the factors that regulate nitrogen fixation in an anoxygenic phototrophic bacterium and found that light and anoxia stimulated nitrogen fixation. The study also revealed the importance of biofilm formation for nitrogen fixation under oxic conditions. These findings highlight the physiological adaptations and the role of light in marine non-cyanobacterial diazotrophs.
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
(2023)
Article
Ecology
Celine Ridame, Julie Dinasquet, Soren Hallstrom, Estelle Bigeard, Lasse Riemann, France Van Wambeke, Matthieu Bressac, Elvira Pulido-Villena, Vincent Taillandier, Frederic Gazeau, Antonio Tover-Sanchez, Anne-Claire Baudoux, Cecile Guieu
Summary: This study found that nitrogen fixation rates in the Mediterranean Sea were related to nutrient conditions, even in the nanomolar range. The impact of Saharan dust deposition on nitrogen fixation and diazotrophic communities was also observed.
