References of "Polar Biology"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailThe cosmopolitan moss Bryum argenteum in Antarctica : back-colonization from extra-regional Pleistocene refugia or in-situ survival
Pisa, S.; Biersma, E.M.; Convey, P. et al

in Polar Biology (2014), 37

Detailed reference viewed: 15 (1 ULg)
Full Text
Peer Reviewed
See detailEffect of melting Antarctic sea ice on the fate of microbial communities studied in microcosms
Lannuzel, D.; Schoenmann, V.; Dumont, I. et al

in Polar Biology (2013), 36(10), 1483-1497

Although algal growth in the iron-deficient Southern Ocean surface waters is generally low, there is considerable evidence that winter sea ice contains high amounts of iron and organic matter leading to ... [more ▼]

Although algal growth in the iron-deficient Southern Ocean surface waters is generally low, there is considerable evidence that winter sea ice contains high amounts of iron and organic matter leading to ice-edge blooms during austral spring. We used field observations and ship-based microcosm experiments to study the effect of the seeding by sea ice microorganisms, and the fertilization by organic matter and iron on the planktonic community at the onset of spring/summer in the Weddell Sea. Pack ice was a major source of autotrophs resulting in a ninefold to 27-fold increase in the sea ice-fertilized seawater microcosm compared to the ice-free seawater microcosm. However, heterotrophs were released in lower numbers (only a 2- to 6-fold increase). Pack ice was also an important source of dissolved organic matter for the planktonic community. Small algae (<10 μm) and bacteria released from melting sea ice were able to thrive in seawater. Field observations show that the supply of iron from melting sea ice had occurred well before our arrival onsite, and the supply of iron to the microcosms was therefore low. We finally ran a “sequential melting” experiment to monitor the release of ice constituents in seawater. Brine drainage occurred first and was associated with the release of dissolved elements (salts, dissolved organic carbon and dissolved iron). Particulate organic carbon and particulate iron were released with low-salinity waters at a later stage. [less ▲]

Detailed reference viewed: 12 (0 ULg)
Full Text
Peer Reviewed
See detailPlectolyngbya hodgsonii: a novel filamentous cyanobacterium from Antarctic lakes
Taton, Arnaud; Wilmotte, Annick ULg; Smarda, Jan et al

in Polar Biology (2011), 34

A special cluster of filamentous, false-branched cyanobacteria, isolated from littoral mat samples in coastal lakes of the Larsemann Hills region (coll. by D. Hodgson) was studied by a polyphasic approach ... [more ▼]

A special cluster of filamentous, false-branched cyanobacteria, isolated from littoral mat samples in coastal lakes of the Larsemann Hills region (coll. by D. Hodgson) was studied by a polyphasic approach. This morphotype has several characters corresponding to the traditional genera Leptolyngbya (morphology of trichomes), Pseudophormidium (type of false branching) or Schizothrix (occasional multiple arrangement of trichomes in the sheaths). However, this cluster of strains is distinctly isolated according to its phylogenetic position (based on 16S rRNA gene sequences), and thus, a separate generic classification is justified. The cytomorphology of this generic entity is also characteristic. Therefore, a new genus (Plectolyngbya with the type species P. hodgsonii) was described. [less ▲]

Detailed reference viewed: 16 (0 ULg)
Full Text
Peer Reviewed
See detailA study of the diatom-dominated microplankton summer assemblages in coastal waters from Terre Adélie to the Mertz Glacier, East Antarctica (139°E–145°E)
Beans, Cristina; Hecq, Jean-Henri ULg; Koubbi, Philippe et al

in Polar Biology (2008), 31(9), 1101-1117

In January 2004 the microplankton community from the coastal waters of Terre Adélie and Georges V Land (139°E - 145°E) was studied. Results showed a diatom-dominated bloom with chlorophyll a levels ... [more ▼]

In January 2004 the microplankton community from the coastal waters of Terre Adélie and Georges V Land (139°E - 145°E) was studied. Results showed a diatom-dominated bloom with chlorophyll a levels averaging 0.64 µg.l-1 at 5m depth (range 0.21 - 1.57 µg.l-1). Three geographic assemblages of diatoms were identified, based on principal diatom taxa abundances. The stratified waters near the Mertz Glacier presented highest phytoplankton biomasses (0.28 - 1.57 µg Chl a.l-1 at 5m) and diatom abundances (6 507 - 70 274 cells.l-1 at 5m), but low diversity, dominated by Fragilariopsis spp. Lower biomasses (0.38 – 0.94 µg Chl a.l-1 at 5m) and abundances (394 – 9 058 cells.l-1 at 5m) were observed in the mixed waters around the Astrolabe Glacier with a diverse diatom community characterised by larger species Corethron pennatum and Rhizosolenia spp. Finally an intermediate zone between them over the shallower shelf waters of the Adélie Bank represented by Chaetoceros criophilus, where biomasses (0.21 - 0.35 µg Chl a.l-1 at 5m) and abundances (1 190 - 5 431 cells.l-1 at 5m) were lowest, coinciding with the presence of abundant herbivorous zooplankton. [less ▲]

Detailed reference viewed: 66 (7 ULg)
Full Text
Peer Reviewed
See detailPotential impact of the main benthic amphipods on the eastern Weddell Sea shelf ecosystem (Antarctica)
Dauby, Patrick ULg; Scailteur, Yves; Chapelle, Gauthier et al

in Polar Biology (2001), 24

Detailed reference viewed: 8 (0 ULg)
Full Text
Peer Reviewed
See detailA stable isotope approach to the eastern Weddell Sea trophic web: focus on benthic amphipods
Nyssen, Fabienne ULg; Brey, Thomas; Lepoint, Gilles ULg et al

in Polar Biology (2001), 25(4),

isotope (C-13/C-12 and N-15/N-14) analyses were performed on 90 species belonging to different benthic communities sampled in the eastern Weddell Sea. The study focused on eight amphipod species whose ... [more ▼]

isotope (C-13/C-12 and N-15/N-14) analyses were performed on 90 species belonging to different benthic communities sampled in the eastern Weddell Sea. The study focused on eight amphipod species whose isotopic composition was compared to their previously described respective gut contents. Amphipod stable isotope ratios correspond fairly accurately to the trophic classification based on gut contents and attest to their wide spectrum of feeding types. Since the fundamental difference between the isotope and the gut content approaches to diet studies is the time scale each method addresses. this coincidence indicates that there would be no significant changes in feeding strategies over time. Three levels of the food web are covered by the eight species and, instead of belonging strictly to one trophic category, amphipods display a continuum of values from the suspension-feeder to scavengers. [less ▲]

Detailed reference viewed: 44 (6 ULg)
Full Text
Peer Reviewed
See detailSeasonal changes of pCO(2) over a subantarctic Macrocystis kelp bed
Delille, Bruno ULg; Delille, D.; Fiala, M. et al

in Polar Biology (2000), 23(10), 706-716

The partial pressure of carbon dioxide (pCO(2)), calculated from pH and total alkalinity measurements. was monitored together with chlorophyll a and bacterioplankton biomass in shallow coastal water ... [more ▼]

The partial pressure of carbon dioxide (pCO(2)), calculated from pH and total alkalinity measurements. was monitored together with chlorophyll a and bacterioplankton biomass in shallow coastal water located inside and outside a giant kelp bed (Macrocystis pyrifera) situated in the Kerguelen Archipelago, Southern Ocean. In spite of large changes over a short time-scale pCO(2) variations over the year are large and exhibit a seasonal pattern in which the different stages of the annual biological turnover are well marked. The overall pattern of pCO(2) variations is related to biological activity (development of both photosynthesis and respiration) during almost the whole year. However, physical and thermodynamical constraints exert a strong influence on pCO(2) at meso time-scale (10 days) and/or when biological activity is weak. Macrocystis acts to maintain pCO(2) below saturation almost the whole year and large undersaturations (pCO(2) as low as 20 mu atm) were observed within the kelp bed. Furthermore, primary production of Macrocystis covers a period of 8 similar to 9 months a year from winter to late summer and the kelp bed seems to favour the spring phytoplanktonic bloom. The buffer factor beta indicates that, outside the kelp bed, inorganic carbon dynamics are mainly influenced by air-sea exchange and photosynthesis without calcification. Inside the kelp bed. beta suggests calcification by the epiphytic community. [less ▲]

Detailed reference viewed: 18 (5 ULg)