Biodiversity and ecophysiology of bacteria associated with Antarctic sea ice

1997 ◽  
Vol 9 (2) ◽  
pp. 134-142 ◽  
Author(s):  
John P. Bowman ◽  
Mark V. Brown ◽  
David S. Nichols
Keyword(s):  
Sea Ice ◽  
Halophilic Bacteria ◽  
Ice Algae ◽  
Bacterial Strains ◽  
Dna Base Composition ◽  
Algae Biomass ◽  
Antarctic Sea Ice ◽  
Dna Base ◽  
Vestfold Hills ◽  
Reference Strains

A total of 135 bacterial strains were isolated from congelation (land fast) sea ice samples and ice algae biomass samples obtained from the coastal areas of the Vestfold Hills in East Antarctica (68°S, 78°E) during the summers of 1992–95. The sea ice isolates, along with reference strains. were analysed by numerical taxonomy and for DNA base composition in order to determine the biodiversity of sea ice bacteria. From these analyses 22 clusters of strains (phena) were obtained with most phena apparently representing novel bacterial taxa. The sea ice isolates could be categorized into three groups based on their ecophysiology: 1) slightly halophilic, psychrophilic bacteria often possessing fastidious growth requirements and which were predominantly isolated from sea ice algae biomass or from algae-rich ice samples; 2) halotolerant and psychrotolerant bacteria; and 3) non-halophilic bacteria isolated primarily from upper sections of congelation ice and other ice samples with low levcls of algal biomass.

scholarly journals Brief Communication: Capturing scales of spatial heterogeneity of Antarctic sea ice algae communities

2016 ◽  
Author(s):  
Alexander L. Forrest ◽  
Lars C. Lund-Hansen ◽  
Brian K. Sorrell ◽  
Isak Bowden-Floyd ◽  
Vanessa Lucieer ◽  
...  
Keyword(s):  
Sea Ice ◽  
Spatial Heterogeneity ◽  
First Year ◽  
Ice Algae ◽  
Ecosystem Response ◽  
Algae Biomass ◽  
Sea Ice Algae ◽  
Antarctic Sea Ice ◽  
Spectral Bands ◽  
Antarctic Waters

Abstract. Identifying spatial heterogeneity of sea ice algae communities is critical to predicting ecosystem response under future climate scenarios. Using an autonomous robotic sampling platform beneath sea ice in McMurdo Sound, Antarctica, we measured irradiance in spectral bands expected to describe the spatial heterogeneity. Derived estimates of ice algae biomass identified patchiness at length scales varying from 50–70 m under first-year sea ice. These results demonstrate that a step-change in how these communities can be assessed and monitored. The developed methodologies could be subsequently refined to further categorize different ice algae communities and their associated productivity in both Arctic and Antarctic waters.

scholarly journals Towards improved estimates of sea-ice algal biomass: experimental assessment of hyperspectral imaging cameras for under-ice studies

2017 ◽  
Vol 58 (75pt1) ◽  
pp. 68-77 ◽  
Author(s):  
Emiliano Cimoli ◽  
Arko Lucieer ◽  
Klaus M. Meiners ◽  
Lars Chresten Lund-Hansen ◽  
Fraser Kennedy ◽  
...  
Keyword(s):  
Sea Ice ◽  
Hyperspectral Imaging ◽  
Algal Biomass ◽  
Large Scale ◽  
Polar Regions ◽  
Ice Algae ◽  
Water Interface ◽  
Algae Biomass ◽  
Distribution Matching ◽  
Ice Water

ABSTRACTIce algae are a key component in polar marine food webs and have an active role in large-scale biogeochemical cycles. They remain extremely under-sampled due to the coarse nature of traditional point sampling methods compounded by the general logistical limitations of surveying in polar regions. This study provides a first assessment of hyperspectral imaging as an under-ice remote-sensing method to capture sea-ice algae biomass spatial variability at the ice/water interface. Ice-algal cultures were inoculated in a unique inverted sea-ice simulation tank at increasing concentrations over designated cylinder enclosures and sparsely across the ice/water interface. Hyperspectral images of the sea ice were acquired with a pushbroom sensor attaining 0.9 mm square pixel spatial resolution for three different spectral resolutions (1.7, 3.4, 6.7 nm). Image analysis revealed biomass distribution matching the inoculated chlorophyll a concentrations within each cylinder. While spectral resolutions >6 nm hindered biomass differentiation, 1.7 and 3.4 nm were able to resolve spatial variation in ice algal biomass implying a coherent sensor selection. The inverted ice tank provided a suitable sea-ice analogue platform for testing key parameters of the methodology. The results highlight the potential of hyperspectral imaging to capture sea-ice algal biomass variability at unprecedented scales in a non-invasive way.

scholarly journals Asaia krungthepensis sp. nov., an acetic acid bacterium in the α-Proteobacteria

2004 ◽  
Vol 54 (2) ◽  
pp. 313-316 ◽  
Author(s):  
Pattaraporn Yukphan ◽  
Wanchern Potacharoen ◽  
Somboon Tanasupawat ◽  
Morakot Tanticharoen ◽  
Yuzo Yamada
Keyword(s):  
Acetic Acid ◽  
Enrichment Culture ◽  
Acetic Acid Bacteria ◽  
Acetic Acid Bacterium ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
16S Rrna Gene Sequences ◽  
Dna Base Composition ◽  
Dna Base ◽  
Type Strains

Three bacterial strains were isolated from flowers collected in Bangkok, Thailand, by an enrichment-culture approach for acetic acid bacteria. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolates were located in the lineage of the genus Asaia but constituted a cluster separate from the type strains of Asaia bogorensis and Asaia siamensis. The DNA base composition of the isolates was 60·2–60·5 mol% G+C, with a range of 0·3 mol%. The isolates constituted a taxon separate from Asaia bogorensis and Asaia siamensis on the basis of DNA–DNA relatedness. The isolates had morphological, physiological, biochemical and chemotaxonomic characteristics similar to those of the type strains of Asaia bogorensis and Asaia siamensis, but the isolates grew on maltose. The major ubiquinone was Q10. On the basis of the results obtained, the name Asaia krungthepensis sp. nov. is proposed for the isolates. The type strain is isolate AA08T (=BCC 12978T=TISTR 1524T=NBRC 100057T=NRIC 0535T), which had a DNA G+C content of 60·3 mol% and was isolated from a heliconia flower (‘paksaasawan’ in Thai; Heliconia sp.) collected in Bangkok, Thailand.

scholarly journals An Under-Ice Hyperspectral and RGB Imaging System to Capture Fine-Scale Biophysical Properties of Sea Ice

2019 ◽  
Vol 11 (23) ◽  
pp. 2860 ◽  
Author(s):  
Emiliano Cimoli ◽  
Klaus M. Meiners ◽  
Arko Lucieer ◽  
Vanessa Lucieer
Keyword(s):  
Sea Ice ◽  
Algal Biomass ◽  
Bottom Topography ◽  
Environmental Drivers ◽  
Future Research ◽  
Ice Algae ◽  
Digital Photogrammetry ◽  
Biophysical Properties ◽  
Algae Biomass ◽  
Non Invasive

Sea-ice biophysical properties are characterized by high spatio-temporal variability ranging from the meso- to the millimeter scale. Ice coring is a common yet coarse point sampling technique that struggles to capture such variability in a non-invasive manner. This hinders quantification and understanding of ice algae biomass patchiness and its complex interaction with some of its sea ice physical drivers. In response to these limitations, a novel under-ice sled system was designed to capture proxies of biomass together with 3D models of bottom topography of land-fast sea-ice. This system couples a pushbroom hyperspectral imaging (HI) sensor with a standard digital RGB camera and was trialed at Cape Evans, Antarctica. HI aims to quantify per-pixel chlorophyll-a content and other ice algae biological properties at the ice-water interface based on light transmitted through the ice. RGB imagery processed with digital photogrammetry aims to capture under-ice structure and topography. Results from a 20 m transect capturing a 0.61 m wide swath at sub-mm spatial resolution are presented. We outline the technical and logistical approach taken and provide recommendations for future deployments and developments of similar systems. A preliminary transect subsample was processed using both established and novel under-ice bio-optical indices (e.g., normalized difference indexes and the area normalized by the maximal band depth) and explorative analyses (e.g., principal component analyses) to establish proxies of algal biomass. This first deployment of HI and digital photogrammetry under-ice provides a proof-of-concept of a novel methodology capable of delivering non-invasive and highly resolved estimates of ice algal biomass in-situ, together with some of its environmental drivers. Nonetheless, various challenges and limitations remain before our method can be adopted across a range of sea-ice conditions. Our work concludes with suggested solutions to these challenges and proposes further method and system developments for future research.

Sedimentation of 13C-rich organic matter from Antarctic sea-ice algae: A potential indicator of past sea-ice extent

Geology ◽  
1999 ◽  
Vol 27 (4) ◽  
pp. 331 ◽  
Author(s):  
John A E. Gibson ◽  
Tom Trull ◽  
Peter D. Nichols ◽  
Roger E. Summons ◽  
Andrew McMinn
Keyword(s):  
Organic Matter ◽  
Sea Ice ◽  
Ice Algae ◽  
Sea Ice Extent ◽  
Sea Ice Algae ◽  
Antarctic Sea Ice ◽  
Potential Indicator

scholarly journals Exploring Spatial Heterogeneity of Antarctic Sea Ice Algae Using an Autonomous Underwater Vehicle Mounted Irradiance Sensor

2019 ◽  
Vol 7 ◽  
Author(s):  
Alexander L. Forrest ◽  
Lars C. Lund-Hansen ◽  
Brian K. Sorrell ◽  
Isak Bowden-Floyd ◽  
Vanessa Lucieer ◽  
...  
Keyword(s):  
Sea Ice ◽  
Spatial Heterogeneity ◽  
Autonomous Underwater Vehicle ◽  
Underwater Vehicle ◽  
Ice Algae ◽  
Sea Ice Algae ◽  
Antarctic Sea Ice

scholarly journals Spatial and seasonal distribution of dissolved and particulate bioactive metals in Antarctic sea ice

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Luis Duprat ◽  
Ashley T. Townsend ◽  
Pier van der Merwe ◽  
Klaus M. Meiners ◽  
Delphine Lannuzel
Keyword(s):  
Sea Ice ◽  
Ice Cores ◽  
Marine Phytoplankton ◽  
Metal Availability ◽  
Ice Algae ◽  
Potential Toxicity ◽  
Phytoplankton Productivity ◽  
Sea Ice Algae ◽  
Antarctic Sea Ice ◽  
Particulate Metal

Iron (Fe) has been shown to limit growth of marine phytoplankton in the Southern Ocean, regulating phytoplankton productivity and species composition, yet does not seem to limit primary productivity in Antarctic sea ice. Little is known, however, about the potential impact of other metals in controlling sea-ice algae growth. Here, we report on the distribution of dissolved and particulate cadmium (Cd), cobalt (Co), copper (Cu), manganese (Mn), nickel (Ni), and zinc (Zn) concentrations in sea-ice cores collected during 3 Antarctic expeditions off East Antarctica spanning the winter, spring, and summer seasons. Bulk sea ice was generally enriched in particulate metals but dissolved concentrations were similar to the underlying seawater. These results point toward an environment controlled by a subtle balance between thermodynamic and biological processes, where metal availability does not appear to limit sea-ice algal growth. Yet the high concentrations of dissolved Cu and Zn found in our sea-ice samples raise concern about their potential toxicity if unchelated by organic ligands. Finally, the particulate metal-to-phosphorus (P) ratios of Cu, Mn, Ni, and Zn calculated from our pack ice samples are higher than values previously reported for pelagic marine particles. However, these values were all consistently lower than the sea-ice Fe:P ratios calculated from the available literature, indicating a large accumulation of Fe relative to other metals in sea ice. We report for the first time a P-normalized sea-ice particulate metal abundance ranking of Fe >> Zn ≈ Ni ≈ Cu ≈ Mn > Co ≈ Cd. We encourage future sea-ice work to assess cellular metal quotas through existing and new approaches. Such work, together with a better understanding of the nature of ligand complexation to different metals in the sea-ice environment, would improve the evaluation of metal bioavailability, limitation, and potential toxicity to sea-ice algae.

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