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See detailDraft Genome of the Axenic Strain Phormidesmis priestleyi ULC007, a Cyanobacterium Isolated from Lake Bruehwiler (Larsemann Hills, Antarctica)
Lara, Yannick ULg; Durieu, Benoit ULg; Cornet, Luc ULg et al

in Genome Announcements (2017)

Phormidesmis priestleyi ULC007 is an Antarctic freshwater cyanobacte- rium. Its draft genome is 5,684,389 bp long. It contains a total of 5,604 protein- encoding genes, of which 22.2% have no clear ... [more ▼]

Phormidesmis priestleyi ULC007 is an Antarctic freshwater cyanobacte- rium. Its draft genome is 5,684,389 bp long. It contains a total of 5,604 protein- encoding genes, of which 22.2% have no clear homologues in known genomes. To date, this draft genome is the first one ever determined for an axenic cyanobacterium from Antarctica. [less ▲]

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See detailCyanobacterial Contribution to Travertine Deposition in the Hoyoux River System, Belgium
Kleinteich, Julia; Golubic, Stjepko; Pessi, Igor S. et al

in Microbial Ecology (2017)

Travertine deposition is a landscape-forming process, usually building a series of calcareous barriers differentiating the river flow into a series of cascades and ponds. The process of carbonate ... [more ▼]

Travertine deposition is a landscape-forming process, usually building a series of calcareous barriers differentiating the river flow into a series of cascades and ponds. The process of carbonate precipitation is a complex relationship between biogenic and abiotic causative agents, involving adapted microbial assemblages but also requiring high levels of carbonate saturation, spontaneous degassing of carbon dioxide and slightly alkaline pH. We have analysed calcareous crusts and water chemistry from four sampling sites along the Hoyoux River and its Triffoy tributary (Belgium) in winter, spring, summer and autumn 2014. Different surface textures of travertine deposits correlated with particular microenvironments and were influenced by the local water flow. In all microenvironments, we have identified the cyanobacterium Phormidium incrustatum (Nägeli) Gomont as the organism primarily responsible for carbonate precipitation and travertine fabric by combining morphological analysis with molecular sequencing (16S rRNA gene and ITS, the Internal Transcribed Spacer fragments), targeting both field populations and cultures to exclude opportunistic microorganisms responding favourably to culture conditions. Several closely related cyanobacterial strains were cultured; however, only one proved identical with the sequences obtained from the field population by direct PCR. This strain was the dominant primary producer in the calcareous deposits under study and in similar streams in Europe. The dominance of one organism that had a demonstrated association with carbonate precipitation presented a valuable opportunity to study its function in construction, preservation and fossilisation potential of ambient temperature travertine deposits. These relationships were examined using scanning electron microscopy and Raman microspectroscopy. [less ▲]

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See detailMolecular Tools for the Detection and Quantification of Toxigenic Cyanobacteria
Kurmayer, Rainer; Sivonen, Kaarina; Wilmotte, Annick ULg et al

Book published by Wiley (2017)

A guide to state-of-the-art molecular tools for monitoring and managing the toxigenicity of cyanobacteria Runaway climate change has made the monitoring and management of toxigenic organisms in the ... [more ▼]

A guide to state-of-the-art molecular tools for monitoring and managing the toxigenicity of cyanobacteria Runaway climate change has made the monitoring and management of toxigenic organisms in the world’s bodies of water more urgent than ever. In order to influence public policy regarding the detection and quantification of those organisms, it is incumbent upon scientists to clearly demonstrate to policy makers the increase of toxigenic cyanobacteria and the threats they pose. As molecular methods can handle many samples in short time, they are the most reliable, cost-effective tools currently available for tracking cyanotoxicity worldwide. This volume arms scientists with the tools they need to track toxigenicity in surface waters and food supplies and, hopefully, to develop new techniques for managing the spread of toxic cyanobacteria. This book offers the first comprehensive treatment of molecular tools for monitoring cyanotoxicity. Growing out of the findings of the landmark European Cooperation in Science and Technology Cyanobacteria project (CYANOCOST), it provides detailed, practical coverage of the full array of available molecular tools and protocols, from water sampling, nucleic acid extraction, and downstream analysis—including PCR and qPCR based methods—to genotyping (DGGE), diagnostic microarrays, and community characterization using next-gen sequencing techniques. [less ▲]

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See detailThe BCCM/ULC collection to conserve the biodiversity and study the secondary metabolites of Polar cyanobacteria
Lara, Yannick ULg; Durieu, Benoit ULg; Renard, Marine ULg et al

Poster (2016, November 16)

In the Polar Regions, Cyanobacteria are the key primary producers and main drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build benthic microbial mats in ... [more ▼]

In the Polar Regions, Cyanobacteria are the key primary producers and main drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build benthic microbial mats in lakes and soil crusts. Their success in these harsh cold conditions can probably be explained by particular adaptations to survive freeze/thaw cycles, seasonally contrasted light intensities, high UV radiations, dessication and other environmental stresses. The BCCM/ULC public collection is funded by the Belgian Science Policy Office since 2011. It has obtained the ISO9001 certification for deposition and distribution of strains, as part of the multi-site certification for the BCCM consortium. This collection aims to gather a representative portion of the polar cyanobacterial diversity with different ecological origins (limnetic mats, soil crusts, cryoconites, endoliths,….) and make it available for researchers to study the taxonomy, evolution, adaptations to harsh environmental conditions, pigments, and genomic make-up. It presently includes 226 cyanobacterial strains, of which 119 are of Antarctic origin (catalogue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). As shown by morphological identification, the strains belong to five orders (Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales). The 16S rRNA and ITS sequences of the strains are being characterized. The first 85 Antarctic strains already studied are distributed into 25 Operational Taxonomic Units (OTUs = groups of sequences with > 97,5% 16S rRNA similarity), and thus, represent a quite large diversity. Moreover, strains identified as members of the genera Leptolyngbya or Phormidium appear in several lineages. This supports the idea that there is a need to revise the taxonomy of these polyphyletic genera with a simple filamentous morphology. To better understand the functioning, metabolism and adaptative strategies of cyanobacteria in the extreme Antarctic environment, the genome sequencing of 11 strains has been started. Pair-read data from illumina MiSeq runs were obtained and submitted to a bioinformatic pipeline dedicated to the assembly of genomes and search of sequences involved in the biosynthesis of secondary metabolites. Gene cluster prediction analysis allowed to characterize 20 clusters of NRPS, PKS and hybrid NRPS-PKS from 2 to 66kb. Surprisingly, none of the characterized operons had previously been described in the literature. [less ▲]

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See detailThe ‘cyanobiome’ of Svalbard, High Arctic
Stelmach Pessi, Igor ULg; Laughinghouse, H Dail; Velazquez, David et al

Poster (2016, October 28)

Over the last decades, the Arctic has experienced a warming trend that is nearly twice as high as the global average, a phenomenon known as ‘Arctic amplification’. The impact of warmer temperatures on ... [more ▼]

Over the last decades, the Arctic has experienced a warming trend that is nearly twice as high as the global average, a phenomenon known as ‘Arctic amplification’. The impact of warmer temperatures on Arctic ecosystems is still unclear. Cyanobacteria are the key primary producers in freshwater and terrestrial Arctic ecosystems, where they are the driver for numerous ecological functions. For a better understanding of the impacts of climate change on Arctic ecosystems, baseline knowledge on cyanobacterial diversity and distribution is crucial. Here we investigate, for the first time, the biogeographic patterns of cyanobacterial communities across Svalbard, using 454 pyrosequencing of partial 16S rRNA gene sequences. Samples were taken from distinct ecosystems and biogeographic zones. We also compare the studied communities with similar Antarctic communities. [less ▲]

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See detailThe BCCM/ULC collection to conserve the biodiversity and explore the applied potential of Polar cyanobacteria
Becker, Pierre; SZTERNFELD, P; ANDJELKOVIC, M et al

Poster (2016, October 28)

In the Polar Regions, Cyanobacteria represent key primary producers and are the main drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build benthic microbial ... [more ▼]

In the Polar Regions, Cyanobacteria represent key primary producers and are the main drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build benthic microbial mats in lakes and soil crusts in terrestrial biotopes. They may present interesting features to survive freeze/thaw cycles, seasonally contrasted light intensities, high UV radiations, dessication and other stresses. The BCCM/ULC public collection funded by the Belgian Science Policy Office since 2011 aims to gather a representative portion of the polar cyanobacterial diversity with different ecological origins (limnetic mats, soil crusts, cryoconites, endoliths…). It makes it available for researchers to study the taxonomy, evolution, adaptations to harsh environmental conditions, and genomic make-up. It presently includes 226 cyanobacterial strains, with 119 being of Antarctic origin (catalogue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). An ISO 9001 certificate was obtained for the public deposition and distribution of strains, as part of the multi-site certification for the BCCM consortium. The morphological identification shows that the strains belong to the orders Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales. The 16S rRNA and ITS sequences of the strains are being characterized. Our results show that the Antarctic strains are positioned into 25 OTUs (sequences with > 97,5% 16S rRNA similarity), and thus, represent a quite large diversity. In addition, cyanobacteria are known to produce a wide range of secondary metabolites (e.g. alkaloids, cyclic and linear peptides, polyketides) with bioactive potential. Among these bioactive metabolites, some display antibiotic, anticancer or antifungal effects. In collaboration with the BCCM/IHEM collection of biomedical fungi, a screening of cyanobacterial strains from BCCM/ULC was performed in order to discover potential new antifungal drugs. The analysis of a first set of methanol extracts from 15 different strains put in evidence the antifungal activity of a Phormidium priestleyi isolate. The latter remains active up to 0.5% (v/v) of fungal culture and was able to inhibit the growth of various fungal species among Candida, Cryptococcus, Aspergillus, and Penicillium. The raw extract was subjected to HPLC and a fraction containing the active molecule was obtained. This molecule appeared to be a thermostable hydrophobic compound. Moreover, in vitro toxicological analyses suggest that the compound has a general cytotoxic effect that could be inhibited by the mammalian metabolism. Further analyses are needed to identify the molecule and to determine if it could be a candidate for a new antifungal drug. In summary, the BCCM/ULC public collection serves as a Biological Resource Centre to conserve ex situ and document the biodiversity of polar cyanobacteria, as well as a repository for discovery of novel bioactive compounds. [less ▲]

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See detailWhy a culture collection of Cyanobacteria?
Wilmotte, Annick ULg; Renard, Marine ULg; Simons, Véronique

Poster (2016, September 08)

The BCCM/ULC public collection is funded by the Belgian Science Policy Office since 2011 and an ISO9001 certificate was obtained for the public deposition and distribution of strains, as part of the multi ... [more ▼]

The BCCM/ULC public collection is funded by the Belgian Science Policy Office since 2011 and an ISO9001 certificate was obtained for the public deposition and distribution of strains, as part of the multi-site certification for the BCCM consortium. The collection aims to gather a representative portion of the polar cyanobacterial diversity with different ecological origins (limnetic mats, soil crusts, cryoconites, endoliths…) and make it available for researchers to study the taxonomy, evolution, adaptations to harsh environmental conditions, and genomic make-up. It presently includes 226 cyanobacterial strains, with 120 being of (Sub) Antarctic origin (http://bccm.belspo.be/catalogues/ulc-catalogue-search). The morphological identification shows that the strains belong to the orders of Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales. Continuous maintenance of living cultures, some of which are also cryopreserved, ensure the preservation and the possibility to rapidly deliver strains to clients for fundamental and applied research. [less ▲]

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See detailCyanobacterial Diversity In Antarctic Aquatic Microbial Mats
Stelmach Pessi, Igor ULg; Lara, Yannick ULg; Durieu, Benoit ULg et al

Poster (2016, September 08)

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See detailSuccessional trajectories of cyanobacterial communities following glacier retreat in Svalbard (High Arctic)
Stelmach Pessi, Igor ULg; Pushkareva, Ekaterina; Borderie, Fabien ULg et al

Conference (2016, September 01)

The effects of global warming are pronounced at high northern latitudes, where the warming trend observed for the past decades is almost twice as the global average. Most glaciers in Svalbard (High Arctic ... [more ▼]

The effects of global warming are pronounced at high northern latitudes, where the warming trend observed for the past decades is almost twice as the global average. Most glaciers in Svalbard (High Arctic) have been retreating and thinning since the end of the Little Ice Age in the late 19th century, and retreat rates have increased substantially in the last decades. As a glacier retreats, it systematically exposes new terrestrial habitats for the colonization by pioneering (micro)organisms. Distance from the glacier terminus can be used as a proxy for time since deglaciation, which makes glacier forefields well suited for the study of primary succession. In the present study, we investigated the successional trajectories of cyanobacterial communities along a 100-year deglaciation gradient in the forefield of two Svalbard glaciers (Ebba- and Hørbyebreen). Cyanobacterial abundance was assessed by epifluorescence microscopy and cyanobacterial diversity was investigated by pyrosequencing of partial 16S rRNA gene sequences. Filamentous cyanobacteria were more abundant than unicellular and heterocystous cyanobacteria in both forefields, and an increase in the abundance of cyanobacteria was observed along the deglaciation gradients. Pseudanabaenales was the most OTU-rich order, followed by Chroococcales, Oscillatoriales, Synechococcales, Nostocales and Gloeobacterales. At the genus level, classified phylotypes were assigned to Leptolyngbya, Phormidium, Nostoc, Pseudanabaena, Chroococcidiopsis and Microcoleus. Interestingly, OTU richness increased along the deglaciation gradient in Ebbabreen, but an inverse correlation was observed in Hørbyebreen. Beta diversity estimations indicated contrasting cyanobacterial phylogenetic structures along the temporal gradient, with a clear separation of initial (10-20 years), intermediate (30-50) and advanced (80-100) communities. Time since deglaciation accounted for around 25% of the phylogenetic variability in both forefields, with organic carbon content also explaining a significant proportion of community turnover along the deglaciation gradients. Taxonomic composition was somewhat constant along the deglaciation gradient, but OTUs associated with initial communities were related to sequences predominantely restricted to polar biotopes, while advanced communities included phylotypes related to cosmopolitan taxa. [less ▲]

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See detailThe BCCM/ULC collection to conserve and study the biodiversity of Polar cyanobacteria
Wilmotte, Annick ULg; Renard, Marine ULg; Lara, Yannick ULg et al

Poster (2016, September)

The BCCM/ULC public collection of Cyanobacteria has been funded since 2011 by the Belgian Science Policy Office. BCCM/ULC is currently holding 226 cyanobacterial strains, with 119 being of Antarctic ... [more ▼]

The BCCM/ULC public collection of Cyanobacteria has been funded since 2011 by the Belgian Science Policy Office. BCCM/ULC is currently holding 226 cyanobacterial strains, with 119 being of Antarctic origin (including 3 from the sub-Antarctic). The cyanobacteria constitute the bacterial phylum with the largest morphological diversity and their taxonomy is still a work in progress. In Polar Regions, Cyanobacteria represent key primary producers and are important drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build extensive benthic microbial mats in lakes and soil crusts in terrestrial biotopes. They have adapted to their environment, and may present interesting features to survive freeze/thaw cycles, seasonally contrasted light intensities, high UV radiations, dessication and other stresses. In this poster, we present the results of the 16S rRNA phylogenetic analysis for 76 Antarctic strains. This allows us to illustrate the diversity present in the collection, to detect lineages for which no genome has yet been sequenced, and to pinpoint taxonomic problems that should be addressed in a more comprehensive study. [less ▲]

Detailed reference viewed: 26 (3 ULg)
See detail) Inviolate areas to protect reference sites for future microbiology research in Antarctica
Wilmotte, Annick ULg; Willems, Anne; Verleyen, Elie et al

Conference (2016, August 22)

Antarctica is a continent dominated by microbes. A surprisingly large biodiversity of well-adapted microorganisms live permanently in a variety of habitats, ranging from ice-free to permanently frozen ... [more ▼]

Antarctica is a continent dominated by microbes. A surprisingly large biodiversity of well-adapted microorganisms live permanently in a variety of habitats, ranging from ice-free to permanently frozen areas. Recent studies revealed that some microbial groups exhibit biogeographic patterns, include endemic taxa and have survived in refugia since the formation of the continental ice sheet. Microbial habitats are under constant pressure due to anthropogenic activities which may introduce non-indigenous microorganisms, via bodies, clothing, cargo and food. New ‘entry points‘ for microbial contamination are a consequence of the increase and diversification of tourism and research stations. Climatic changes might furthermore increase the probability of the successful establishment of populations of non-native taxa. The impacts of such introductions are still unknown, and might lead to a loss of the native microbial biodiversity, or its modification, which in turn might affect ecosystem functioning. The recent technical progress in molecular methodologies have generated very sensitive high-throughput analyses and have the potential to describe microbial communities with unprecedented detail. However, we may be losing the pristine Antarctic areas that would enable scientists to study the native microbial flora, its functions and properties. The Protocol on Environmental Protection of the Antarctic Treaty foresees the designation of Antarctic Specially Protected Areas (ASPA) to protect “outstanding environmental, scientific, historic, aesthetic, or wilderness values, any combination of those values, or on-going or planned scientific research” (http://www.ats.aq/e/ep_protected.htm). However, the designation of ASPAs has not followed a systematic planning, and often focused on the conservation of large mammals, birds and/or vegetation and other iconic species. Microorganisms have the handicap of generally being invisible without a microscope and relevant expertise, and require molecular methods for species delineation. Terrestrial habitats are protected in 55 out of the 72 existing ASPAs (in total less than 700 km2). Microalgae are protected in 16 ASPAs, cyanobacteria in 7 and snow microalgae in 3. Only 8 ASPAs mention ‘Microbial habitats’, ‘microbial communities’ or ‘soil and lake microflora’. One tool of the Protocol that could be specifically used to protect microbial habitats is the creation of inviolate areas where a special entry permit is required (inside ASPAs, for example), and quarantine equipment should be worn. These zones could be set aside for future research and after a few decades, they would be unique examples of truly pristine habitats, and representative of the native microbial diversity. Examples of this are ASPA 126, Byers Peninsula, and ASPA 172, Lower Taylor Glacier and Blood Falls. Such an option would require discussions and a consensus among scientists of other disciplines than microbiology to select these regions, and develop careful management protocols of the sites and their vicinity. In addition, gaps in our knowledge should be addressed, like the extent of transportation of microorganisms by natural means (winds, birds...), and the probability of subsequent colonization of new areas by microorganisms coming from other Antarctic regions or from outside Antarctica. Let’s hope that the dialogue between scientists and policy makers will improve the conservation of Antarctic microbial diversity and safeguard the possibility to study these unique communities in the future by the next generation of scientists, with the most advanced techniques of the time. [less ▲]

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See detailThe BCCM/ULC collection: a Biological Ressource Center to give access to the Antarctic cyanobacterial diversity
Wilmotte, Annick ULg; Renard, Marine ULg; Lara, Yannick ULg et al

Poster (2016, August)

On the Antarctic continent, Cyanobacteria represent the key primary producers and the main drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build benthic ... [more ▼]

On the Antarctic continent, Cyanobacteria represent the key primary producers and the main drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build benthic microbial mats in lakes and soil crusts in terrestrial biotopes. They may present interesting features to survive freeze/thaw cycles, sea-sonally contrasted light intensities, high UV radiations, dessication and other stresses. The BCCM/ULC public collection funded by the Belgian Science Policy Office since 2011 aims to gather a representative portion of the polar cyanobacterial diversity with different ecological origins (limnetic microbial mats, soil crusts, cryoconites, endoliths, etc.). It makes it available for researchers to study the taxonomy, evolu-tion, adaptations to harsh environmental conditions, and genomic make-up. It pres-ently includes 226 cyanobacterial strains, with 119 being of Antarctic origin (cata-logue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). The morphological identification shows that the strains belong to the orders Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales. We present here the molecular datasets showing the diversity of the BCCM/ULC strains, studied on the basis of the 16S rRNA gene. A selection of strains was also characterized by sequencing of rpoC1, recA, and gyrA genes after amplification with newly designed primers. Our results mainly show that 25 OTUs included strains of Antarctic origin. Moreo-ver, strains identified as members of the genera Leptolyngbya or Phormidium ap-pear in several lineages. This supports the need to revise these polyphyletic genera with a simple filamentous morphology. A certain divergence of some Antarctic strains from related strains isolated from other regions can also be observed. It suggests that a portion of the Antarctic cyanobacterial flora may have evolved in-dependently from the cyanobacteria in other continents. [less ▲]

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See detailMicroalgae diversity along an Antarctic glacier forefield
Stelmach Pessi, Igor ULg; Rybalka, Natalia; Friedl, Thomas et al

Poster (2016, August)

Glacier retreat due to global warming has been observed in all the cryosphere [1], systematically exposing new terrestrial ecosystems that had previously been covered by ice. Primary succession, i.e. the ... [more ▼]

Glacier retreat due to global warming has been observed in all the cryosphere [1], systematically exposing new terrestrial ecosystems that had previously been covered by ice. Primary succession, i.e. the assembly of biological communities on newly exposed habitats and their change over time, can be studied along glacier forefields, where distance from the glacier terminus is used as a proxy for time since deglaciation [2]. The study of microbial succession is still at its infancy, but understanding the relationships between microbial communities and soil development will provide us with crucial knowledge on how they influence and respond to changes in environmental conditions. Here, we investigated the structure of microalgal communities along a deglaciation gradient in the forefield of Collins Glacier (Fildes Peninsula, King George Island, Maritime Antarctica). [less ▲]

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See detailDiversity and distribution of microorganisms in microbial mats of Antarctic lakes
Lara, Yannick ULg; Durieu, Benoit ULg; Stelmach Pessi, Igor ULg et al

Conference (2016, August)

The BelSPO project CCAMBIO aims to study the biogeographical distribution of microorganisms in lacustrine microbial mats using a combination of techniques including microscopic observations, strain ... [more ▼]

The BelSPO project CCAMBIO aims to study the biogeographical distribution of microorganisms in lacustrine microbial mats using a combination of techniques including microscopic observations, strain isolation and genetic characterisation, and molecular diversity assessments using Next Generation Sequencing of environmental DNA. The samples were collected in different Antarctic and sub-Antarctic biogeographical regions. Preliminary multivariate analysis of >130 samples revealed strong bioregionalisation patterns in microbial eukaryotes, which are in agreement with the classical subdivision of the Antarctic Realm into Maritime Antarctica, Continental Antarctica and the Sub-Antarctic Islands generally observed in plants and animals. The biogeographic structuring was less strong between the continent and Maritime Antarctica in prokaryotes suggesting more regular dispersal events between these two regions. The Sub-Antarctic assemblages harboured more complex foodwebs, with arthropods, nematods, rotifers, flatworms and annelids as main metazoan groups. Lakes on the continent, however, were characterised by fewer metazoan groups and a greater importance of microbial herbivores and secondary consumers, including a relative high diversity of ciliates and tardigrades. In a first analysis of microbial mats from five Antarctic lakes and an aquatic biofilm from the Sub-Antarctic, the majority of the cyanobacterial OTUs retrieved were related to filamentous taxa such as Leptolyngbya and Phormidium, which are common genera in Antarctic lacustrine microbial mats. However, other phylotypes related to different taxa such as Geitlerinema, Pseudanabaena, Synechococcus, Chamaesiphon, Calothrix and Coleodesmium were also found. Results revealed a much higher diversity than what had been reported using traditional methods and also highlighted remarkable differences between the cyanobacterial communities of the studied lakes. In the coming months, the molecular diversity data will be deposited into the “Microbial Antarctic Resource System (MARS)” presently developed into the webportal ‘biodiversity.aq’. Better knowledge of the diversity and distribution of microorganisms will contribute to a better assessment of their resilience and local/regional responses to global change [less ▲]

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See detailCyanobacterial diversity in soil crusts in the Sör Rondane Mountains
Namsaraev, Zorigto; Mano, Marie-José; Wilmotte, Annick ULg

Poster (2016, August)

Antarctica is the only continent that is dominated by microbial (cyanobacteria and algae) and lower plant (predominantly mosses and lichens) communities. Cyanobacteria are photosynthetic bacteria that ... [more ▼]

Antarctica is the only continent that is dominated by microbial (cyanobacteria and algae) and lower plant (predominantly mosses and lichens) communities. Cyanobacteria are photosynthetic bacteria that require solar light, liquid water, air and some mineral nutrients for growth. They serve as primary producers of organic matter in Antarctic ecosystems providing energy to other physiological groups of microorganisms and invertebrates. Cyanobacteria form macroscopically visible crusts or thin biofilms on the surface of soils and rocks, or occupy endolithic niches in Antarctic mountains. Mountains exposed above the ice sheet could have remained ice-free during glaciation maxima in Antarctica. They could serve as a refuge for terrestrial biodiversity and potential source for recolonization of surrounding habitats during glacier retreat. Cyanobacterial diversity in habitats located above 1 km a.s.l. was studied in several Antarctic locations. These include: the Vinson Massif in Ellsworth Mountains (2000-2500 m a.s.l.), Beacon (1176 m a.s.l.) and University Valleys (1700 m a.s.l.) in the "stable upland zone" of the McMurdo Dry Valleys (Southern Victoria Land) and the Sör Rondane Mountains (1370-1700 m a.s.l.) (Yergeau et al., 2007; Wood et al., 2008; Fernandez-Carazo et al., 2012). The goal of our work was to study cyanobacterial diversity of cyanobacteria in the Sör Rondane Mountains in the vicinity of Belgian Princess Elisabeth Station. Previous estimates of the diversity showed the presence of 10 morphotypes and 13 OTUs of cyanobacteria in 10 samples of biofilms and microbial crusts (Fernandez-Carazo et al., 2012). We performed a broader sampling and studied cyanobacterial diversity using DGGE with cyanospecific primers and microscopy. In 126 samples, we observed 15 morphotypes of cyanobacteria. 28 representative samples were selected for molecular analyses that revealed the presence of 28 OTUs (groups of 16S rRNA sequences sharing at least 97,5% sequence similarity). Comparison with other mountainous areas of Antarctica showed that the Sör Rondane Mountains harbor a significantly higher cyanobacterial diversity. Molecular analysis of the cyanobacterial diversity in Beacon Valley didn't show the presence of cyanobacteria (Wood et al., 2008), though a strain of Chroococcidiopsis sp. (CCMEE 134) was isolated from a sample collected there (Billi et al., 2011). A strain of Chroococcidiopsis sp. (CCMEE 171-A789-2) was also isolated from samples collected in University Valley (Cumbers & Rothschild, 2014). 5 OTUs of cyanobacteria were detected in samples collected in Ellsworth Mountains despite of the presumably harsher climate (78°31′S latitude compared to 77°49′S for Beacon Valley) and higher altitude (Yergeau et al., 2007). No reliable climate data are available for the discussed areas, except for the Sor Rondane Mountains. We propose that the higher diversity of cyanobacteria detected near the Princess Elisabeth Station could be explained by a more intensive sampling or by a more northern location of the area (72°0′S). [less ▲]

Detailed reference viewed: 20 (2 ULg)
Peer Reviewed
See detailCharacterization of Leptolyngbya and Phormidium diversity in Antarctic biotopes
Lara, Yannick ULg; Durieu, Benoit ULg; Borderie, Fabien et al

Poster (2016, August)

Detailed reference viewed: 15 (6 ULg)
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See detailNarrowing the science/policy gap for environmental management
Hughes, Kevin A; Liggett, Daniela; Roldan, Gabriela et al

in Antarctic Science (2016), 28(5), 325

Antarctic terrestrial and marine environments are under increasing pressure from national operator activities, tourism and climate change. The Protocol on Environmental Protection to the Antarctic Treaty ... [more ▼]

Antarctic terrestrial and marine environments are under increasing pressure from national operator activities, tourism and climate change. The Protocol on Environmental Protection to the Antarctic Treaty provides overarching legislation concerning the environmental management of the Treaty area, with 2016 marking the Protocol’s 25th anniversary. The Protocol also established the Committee for Environmental Protection (CEP) to provide advice to the Antarctic Treaty Consultative Meeting (ATCM) on environmental matters. Today, the CEP’s Five-Year Work Plan and Climate Change Response Work Programme lists and prioritises issues that need to be addressed to ensure impacts in Antarctica by human activities are both recognized andminimised.Despite all of this, recent evaluations have suggested that a slow pace of environmental policy development presents a significant threat to effective Antarctic conservation. Progress on many environmental issues, including wildlife disturbance, the conservation status of Antarctic species, area protection and pollution management, is glacial or has stalled completely. Whilst in some cases capacity issues concerning those responsible for Antarctic environmental policy work may be a contributing factor, the level of interaction between researchers and those responsible for environmental management and decision-making is also of importance. Without quality science - and effective interpretation of research results - policymakers have little evidence on which to base their decisions. But researchers need to know policymakers’ needs. Two-way communication is essential: policymakers could ask the research community to answer specific environmental questions, and, in turn, researchers could present evidence-based recommendations and highlight emerging threats. But how is this to be funded? Ultimately, effective communication is needed between national government departments responsible for funding Antarctic research and those dealing with Antarctic environmental protection. Hopefully, this will ensure essential research informing environmental policy decisions is adequately resourced. In reality, the cost is likely to be trivial compared with the resources spent by Parties on Antarctic logistics. [less ▲]

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See detailCryopreservation of cyanobacteria in the BCCM/ULC collection: experimental set-up of protocols
Crahay, Charlotte ULg; Renard, Marine ULg; Day, John G et al

Conference (2016, June 21)

Detailed reference viewed: 24 (2 ULg)
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See detailDevelopment of improved preservation techniques for cyanobacterial and diatom strains in the BCCM collections
Crahay, Charlotte ULg; Chepurnova, Olga; Day, John G et al

Poster (2016, June)

Detailed reference viewed: 24 (1 ULg)
See detailThe CCAMBIO project to characterize the biodiversity and distribution of microorganisms in microbial mats of Antarctic lakes
Durieu, Benoit ULg; Lara, Yannick ULg; Obbels, Dagmar et al

Poster (2016, April 29)

The BelSPO project CCAMBIO aims to study the biogeographical distribution of microorganisms in lacustrine microbial mats using a combination of techniques including microscopical observations (light and ... [more ▼]

The BelSPO project CCAMBIO aims to study the biogeographical distribution of microorganisms in lacustrine microbial mats using a combination of techniques including microscopical observations (light and electronic microscopy), strain isolation, and molecular diversity assessment using Next Generation Sequencing. The samples were collected in different Antarctic and sub-Antarctic biogeographical regions. A detailed microscopic study of the Antarctic diatom diversity allowed to revise a number of taxa and discover new ones. A multivariate analysis of diatoms showed that these regions hosted different diatom flora. Endemic diatom taxa were also observed, and a multigene molecular phylogeny of Pinnularia borealis showed a high genetic diversity. Pilot studies were conducted for the microeukaryotes and cyanobacteria to select NGS protocols and bioinformatic pipelines. Preliminary multivariate analysis of over 100 samples revealed that distinct biogeographic zones could be recognized in both the prokaryote and eukaryote data, which is in agreement with the classical subdivision of the Antarctic Realm into Maritime Antarctica, Continental Antarctica and the Sub-Antarctic Islands generally observed in plants and animals. Moreover, Sub-Antarctic assemblages harboured more complex foodwebs, with quite diverse metazoan groups. Lakes on the continent, however, were characterised by fewer metazoan groups and a greater importance of microbial herbivores and secondary consumers, including a relative high diversity of ciliates and tardigrades. Variation partitioning analysis revealed that spatial variables that approximated large-scale regional contrasts in historical (e.g. deglaciation history, geological origin) and climatic factors (e.g. mean annual air temperature) significantly explained the largest portion of the observed variation in community structure for eukaryotes, while in the prokaryote data environmental gradients related to conductivity were more important. In a first analysis of microbial mats from five Antarctic lakes and an aquatic biofilm from the Sub-Antarctic, the majority of the cyanobacterial OTUs retrieved were related to filamentous taxa such as Leptolyngbya and Phormidium, which are common genera in Antarctic lacustrine microbial mats. However, other phylotypes related to different taxa such as Geitlerinema, Pseudanabaena, Synechococcus, Chamaesiphon, Calothrix and Coleodesmium were also found. Results revealed a higher diversity than what had been reported using traditional methods based on microscopic observations and cultivation and also highlighted remarkable differences between the cyanobacterial communities of the studied lakes. In the next months, the molecular diversity data will be deposited into the “Microbial Antarctic Resource System (MARS)” presently developed into the webportal ‘biodiversity.aq’. The better knowledge of the diversity and distribution of microorganisms will contribute to a better assessment of their resilience and local/regional responses to global change. [less ▲]

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