A further contribution on the biology of the Antarctic flea,Glaciopsyllus antarcticus (Siphonaptera: Ceratophyllidae)

Summary Experiments showed that adult Antarctic Fleas Gladopsyllus antarcticus preferred dark over light conditions, dry over wet conditions, and fine substrate over coarse substrate. Examination of seabird chicks and collections of nest material indicated that the Southern Fulmar Fulmarus glacialoides, is the major host species of the Antarctic Flea, while Snow Petrels Pagodroma nivea, Cape Petrels Daption capense, Antarctic Petrels Thalassoica antarctica, and Wilson's Storm-Petrels Oceanites oceanicus are minor hosts. This is the first report of Antarctic Fleas occuring on either Antarctic Petrels or Wilson's Storm-Petrels. No fleas were found associated with Southern Giant Petrels Macronectes giganteus, Antarctic Skuas Catharacta maccormicki, or Adelie Penguins Pygoscelis adeliae. No live fleas were found in Southern Fulmar nest material during their period of dispersal over the winter months, supporting the hypothesis that Antarctic Fleas survive the winter period by remaining on their seabird host.     

Diversity of the cyanobacterial microflora of the northern part of James Ross Island,NW Weddell Sea,Antarctica

The diversity and ecological distribution of cyanobacteria in the northern, deglaciated part of James Ross Island were studied during the Antarctic summer season 2005–2006. Seventy-five cyanobacterial morphotypes were observed in various habitats of this area. The identified cyanobacterial taxa belong to the characteristic and dominant types of coastal Antarctica, and majority of them appeared connected to special habitats and formed distinct populations and ecologically delimited communities. The results are compared and discussed with respect to phenotypically characterised cyanobacterial microflora of maritime Antarctica and to recent molecular analyses of cyanobacterial strains from different Antarctic regions. The existence of a specificity and characteristic composition of Antarctic cyanobacterial communities was demonstrated.     

Red Shift,Blue Shift: Investigating Doppler Shifts,Blubber Thickness,and Migration as Explanations of Seasonal Variation in the Tonality of Antarctic Blue Whale Song

The song of Antarctic blue whales (Balaenoptera musculus intermedia) comprises repeated, stereotyped, low-frequency calls. Measurements of these calls from recordings spanning many years have revealed a long-term linear decline as well as an intra-annual pattern in tonal frequency. While a number of hypotheses for this long-term decline have been investigated, including changes in population structure, changes in the physical environment, and changes in the behaviour of the whales, there have been relatively few attempts to explain the intra-annual pattern. An additional hypothesis that has not yet been investigated is that differences in the observed frequency from each call are due to the Doppler effect. The assumptions and implications of the Doppler effect on whale song are investigated using 1) vessel-based acoustic recordings of Antarctic blue whales with simultaneous observation of whale movement and 2) long-term acoustic recordings from both the subtropics and Antarctic. Results from vessel-based recordings of Antarctic blue whales indicate that variation in peak-frequency between calls produced by an individual whale was greater than would be expected by the movement of the whale alone. Furthermore, analysis of intra-annual frequency shift at Antarctic recording stations indicates that the Doppler effect is unlikely to fully explain the observations of intra-annual pattern in the frequency of Antarctic blue whale song. However, data do show cyclical changes in frequency in conjunction with season, thus suggesting that there might be a relationship among tonal frequency, body condition, and migration to and from Antarctic feeding grounds.     

Taxonomy and richness of yeasts associated with angiosperms,bryophytes, and meltwater biofilms collected in the Antarctic Peninsula

Extremophiles - The interest in the diversity of yeasts in the Antarctic environment has increased in recent years, mainly because Antarctic microbiology is a recent science, and little is known...     

The morphology and anatomy of the Antarctic gastropod Bathyberthella antarctica (Opisthobranchia, Notaspidea, Pleurobranchidae)

The external morphology, anatomy and histology of the Antarctic notaspidean Bathyberthella antarctica Willan & Bertsch, 1987 is described and the intraspecific variability presented. The species is compared with the only other known pleurobranch from the high Antarctic zone, Tomthompsonia antarctica (Thiele, 1912).     

Accumulation of vanadium, manganese, and nickel in Antarctic tunicates

The vanadium, manganese, and nickel contents of nine species of Antarctic tunicates were determined by atomic absorption spectroscopy. The Antarctic species Distaplia cylindrica contained significantly more vanadium (1,445 ppm dry weight) than the other Antarctic tunicates investigated. Antarctic Ascidia sp. was also shown to accumulate considerable amounts of vanadium (567 ppm). Low levels of bioaccumulated manganese (<50 ppm) and nickel (<15 ppm) were observed in all tunicates examined.     

Testing for endemism, genotypic diversity and species concepts in Antarctic terrestrial microalgae of the Tribonemataceae (Stramenopiles, Xanthophyceae)

The genetic diversity of all available culture strains of the Tribonemataceae ( Stramenopiles , Xanthophyceae ) from Antarctica was assessed using the chloroplast-encoded psbA /rbcL spacer region sequences, a highly variable molecular marker, to test for endemism when compared with their closest temperate relatives. There was no species endemic for Antarctica, and no phylogenetic clade corresponded to a limited geographical region. However, species of the Tribonemataceae may have Antarctic populations that are distinct from those of other regions because the Antarctic strain spacer sequences were not identical to sequences from temperate regions. Spacer sequences from five new Antarctic isolates were identical to one or more previously available Antarctic strains, indicating that the Tribonemataceae diversity in Antarctic may be rather limited. Direct comparisons of the spacer sequences and phylogenetic analyses of the more conserved rbcL gene revealed that current morphospecies were inadequate to describe the actual biodiversity of the group. For example, the genus Xanthonema , as currently circumscribed, was paraphyletic. Fortunately, the presence of distinctive sequence regions within the psbA/rbcL spacer, together with differences in the rbcL phylogeny, provided significant autoapomorphic criteria to re-define the Tribonemataceae species.     

Feeding habits of three seal species at the Danco Coast, Antarctica: a re-assessment

The analysis of prey overlap among Weddell, Antarctic fur and leopard seals was conducted using fecal samples collected at the Danco Coast, Antarctic Peninsula, in 1998 and 2000. The re-occurrence of prey species was moderate in samples collected in 1998, and low in 2000, and reflects resource partitioning among seal species. Prey species that mostly co-occurred in seals’ diet were the Antarctic krill Euphausia superba, bivalves, and the myctophids Gymnoscopelus nicholsi and Electrona antarctica. A dietary similarity index of prey overlap has been calculated and demonstrates evident fluctuations in pairwise comparisons between the seal species. The highest and lowest values of prey overlap were observed between Antarctic fur seals and leopard seals, and between Weddell seals and leopard seals, respectively. Prey overlap between Antarctic fur seals and Weddell seals was moderate in both seasons.     

Mixoscyphus antarcticus gen. nov., sp. nov. (Cnidaria, Hydrozoa, Sertulariidae), the first truly endemic genus of Antarctic benthic hydroids

A genus and species of Antarctic benthic hydroids new to science, Mixoscyphus antarcticus gen. nov., sp. nov., is described and figured. Its systematic position amongst allied genera of the family Sertulariidae is discussed. The studied material originates from the South Shetland Islands area (West Antarctica), which was collected by several Spanish and US Antarctic expeditions. Mixoscyphus gen. nov. currently represents the only complete endemic genus of Antarctic benthic hydrozoans. A discussion of other genera of benthic hydroids that are largely endemic to the Antarctic is also provided.     

Diversity of the lichenized fungi in King George Island, Antarctica, revealed by phylogenetic analysis of partial large subunit rDNA sequences

Lichens are predominant and important components of flora in the terrestrial ecosystem of Antarctica. However, relatively few researches on the phylogenetic position of Antarctic lichen-forming fungi have been accomplished. In this study, partial sequences of nuclear large subunit rDNAs from 50 Antarctic specimens were obtained and the phylogeny was reconstructed. Antarctic lichen species were distributed among 4 orders, including the monophyletic order Agyrales, paraphyletic orders Pertusariales and Teloschistales, and polyphyletic order Lecanorales. Species diversity was highest in the order Lecanorales, followed by Teloschistales and Pertusariales. Based on the phylogeny and sequence similarity analyses, it is proposed that the taxonomy of Stereocaulon alpinum, Physcia caesia, Usnea aurantiacoatra, and Cladonia species should be revised by careful examination of their phenotypic and molecular characteristics. Six species known to be endemic to Antarctica, Catillaria corymbosa, Himantormia lugubris, Leptogium puberulum, Pertusaria pertusa, Rhizoplaca aspidophora, and Umbilicaria antarctica, formed unique lineages, implying independent origins in the Antarctic area.     

Seasonal acoustic occurrence,diel-vocalizing patterns and bioduck call-type composition of Antarctic minke whales off the west coast of South Africa and the Maud Rise,Antarctica

Seasonal occurrence, diel-vocalizing patterns, and call-types of Antarctic minke whales are described using bio-acoustic recordings from the west coast of South Africa and the Maud Rise, Antarctica. In Antarctica, minke whale bioduck calls were detected in seven of nine months of hydrophone deployment (peaking in May and September) while downsweeps were only detected in June. Bioduck calls were sporadically detected in South African waters with peak calling in September/October, and no bioducks were detected from March through August. Bioduck call occurrence was high during daytime in Antarctica but there was no diel-vocalizing pattern in South African waters. We split bioduck B call-type into two subtypes: B1 with 13 ± 1 pulses (Dominello & Širović, 2016) and B2 with 9 ± 1 pulses (this study). Bioduck B2 was detected both in Antarctic and South African waters, with harmonics up to 2 kHz. Similar bioduck call-types were detected in Antarctic and South African waters, with bioduck A2 being the most common. Month of the year was the most important predictor of bioduck occurrence both in Antarctic and South African waters. This is the first study to describe the seasonal occurrence, diel-vocalizing behavior and call-types of Antarctic minke whales off the South African west coast and eastern Weddell Sea.     

Aspects of the biology of the midge,Eretmoptera murphyi Schaeffer (Diptera: Chironomidae), introduced to Signy Island,maritime Antarctic

Summary The biology of a population of the subantarctic chironomid midge Eretmoptera murphyi Schaeffer, introduced to Signy Island in the maritime Antarctic more than 20 years ago, is described. Investment in reproduction by the parthenogenetic adult females is high, with individuals producing single egg batches containing ca. 85 eggs and having a dry weight of more than twice that of the spent female. In culture, egg development rates to hatching are increased significantly by increasing temperature from 2° to 12°C (a range covering mean summer temperatures found in the species' maritime Antarctic habitat, and natural habitat in the subantarctic). The gelatinous matrix of the egg batch forms a skin on drying, which may reduce further water loss, and allow the eggs or pre-emergence larvae to survive the short periods of desiccating conditions likely to occur in their natural habitat. The biology of E. murphyi is compared with that of the endemic maritime Antarctic species Belgica antarctica, showing much similarity. E. murphyi possesses several preadaptations which allow it to survive the harsher conditions of the maritime Antarctic.     

The morphology and taxonomy of the Antarctic species of Tritonia Cuvier, 1797 (Nudibranchia: Dendronotoidea)

The external morphology and anatomy of the Antarctic nudibranchs Tritonia vorax Odhner, 1926, and Tritonia antarctica Pfeffer in Martens & Pfeffer, 1886, is redescribed in detail and compared with other nominal tritoniids from the Antarctic and Subantarctic waters. Tritonia appendiculata Eliot, 1905, T. challengeriana Eliot, 1907a, non Bergh, 1884, T. chalkngeriana Odhner 1926, non Bergh, 1884, and Marionia cmullata Vicente & Arnaud 1974, non (Couthouy, in Gould 1852), are shown to be synonymous with T. antarctica. Only Tritonia antarctica is a true High Antarctic species, with a distribution around the continental shelf, Antarctic Peninsula and South Georgia. T. vorax is confined to South Georgia and Subantarctic waters.     

Spectral Properties of the Green Alga Trebouxia,a Phycobiont of Cryptoendolithic Lichens in the Antarctic Dry Valley

An algologically pure culture of the green alga Trebouxia, a phycobiont of cryptoendolithic lichens, was isolated from sandstone samples collected in the high-altitude polar regions of Antarctica. The absorption and second-derivative absorption spectra of acetone extract of the Antarctic phycobiont cells were studied in comparison with those of a Trebouxia phycobiont isolated recently from a Parmeliaceae lichen in the Mid-European climatic zone. The cells of the Antarctic phycobiont were characterized by a lower content of chlorophyll a and a higher ratio of chlorophyll b and carotenoids to chlorophyll a as compared to the Mid-European phycobiont. Furthermore, the carotenoids of the Antarctic phycobiont were more diverse. The low-temperature fluorescence spectra of the Antarctic phycobiont were characterized by an increased intensity of the short-wavelength fluorescence peak of chlorophyll aand a diminished intensity of fluorescence in the long-wavelength spectral region.     

Extinction and recolonization of maritime Antarctica in the limpet Nacella concinna (Strebel, 1908) during the last glacial cycle: toward a model of Quaternary biogeography in shallow Antarctic invertebrates

Quaternary glaciations in Antarctica drastically modified geographical ranges and population sizes of marine benthic invertebrates and thus affected the amount and distribution of intraspecific genetic variation. Here, we present new genetic information in the Antarctic limpet Nacella concinna, a dominant Antarctic benthic species along shallow ice‐free rocky ecosystems. We examined the patterns of genetic diversity and structure in this broadcast spawner along maritime Antarctica and from the peri‐Antarctic island of South Georgia. Genetic analyses showed that N. concinna represents a single panmictic unit in maritime Antarctic. Low levels of genetic diversity characterized this population; its median‐joining haplotype network revealed a typical star‐like topology with a short genealogy and a dominant haplotype broadly distributed. As previously reported with nuclear markers, we detected significant genetic differentiation between South Georgia Island and maritime Antarctica populations. Higher levels of genetic diversity, a more expanded genealogy and the presence of more private haplotypes support the hypothesis of glacial persistence in this peri‐Antarctic island. Bayesian Skyline plot and mismatch distribution analyses recognized an older demographic history in South Georgia. Approximate Bayesian computations did not support the persistence of N. concinna along maritime Antarctica during the last glacial period, but indicated the resilience of the species in peri‐Antarctic refugia (South Georgia Island). We proposed a model of Quaternary Biogeography for Antarctic marine benthic invertebrates with shallow and narrow bathymetric ranges including (i) extinction of maritime Antarctic populations during glacial periods; (ii) persistence of populations in peri‐Antarctic refugia; and (iii) recolonization of maritime Antarctica following the deglaciation process.     

Protoperidiniacean dinoflagellate cyst taxa from the Upper Miocene of ODP Leg 178, Antarctic Peninsula

Protoperidiniacean dinoflagellate cysts have been recovered from Upper Miocene sediments of Hole 1095, ODP Leg 178, drilled to the west of the Antarctic Peninsula. These cysts make up virtually the entire dinoflagellate cyst assemblages, and three new species are formally described herein as Selenopemphix bothrion sp. nov., Selenopemphix kepion sp. nov. and Selenopemphix minys sp. nov., together with one informal taxon and two species attributed to published taxa. The occurrence of Late Miocene protoperidiniacean-dominated assemblages in the vicinity of the Antarctic continent is of special interest. Their presence may indicate the initiation of the Antarctic Circumpolar Current and increased nutrient supply within the Southern Ocean as the Antarctic Divergence became established. A comparison with several other protoperidiniacean dinoflagellate assemblages of similar age in other parts of the world provides some preliminary evidence for possible concomitant oceanographic change at this time.     

Barcoding Antarctic Biodiversity: current status and the CAML initiative,a case study of marine invertebrates

The Census of Antarctic Marine Life (CAML) aims to collate DNA barcode data for Antarctic marine species. DNA barcoding is a technique that uses a short gene sequence from a standardised region of the genome as a diagnostic ‘biomarker’ for species. This study aimed to quantify genetic data currently available in GenBank in order to establish whether a representative cross-section of Antarctic marine taxa and bio-geographic areas has been sequenced and to propose priorities for barcoding, with a particular emphasis on marine invertebrate species. It was found that, amongst marine invertebrate fauna, sequence information covers a limited range of taxa and areas—mainly Crustacea, Annelida and Mollusca from the Weddell Sea and the Antarctic Peninsula. Only 15% of genes sequenced in Antarctic marine invertebrates were the standard barcode gene cytochrome c oxidase subunit 1 (CO1), the majority were other nuclear and mitochondrial genes. There is an urgent need for more in-depth genetic barcoding and species identification studies in Antarctic science, from a range of taxa and areas, given the rate of climate-driven habitat changes that might lead to extinctions in the region. CAML hopes to redress the balance, by collecting and sequencing over the circum-Antarctic area, using material from voyages that occurred during 2008 and 2009, within the framework of the International Polar Year (IPY).     

Aspects of the foraging behaviour of the Antarctic Tern Sterna vittata gaini at Harmony Point, South Shetland Islands

During January and February of 2002 and 2003, we studied the diet of the Antarctic Tern Sterna vittata gaini at two colonies in Nelson Island, South Shetland Islands, by identifying the prey fed to chicks by breeders. The fish Notothenia coriiceps was the main prey in both seasons, followed by the myctophid Electrona antarctica, Antarctic krill Euphausia superba and gammarid amphipods. The contribution of fish to the diet increased as chicks grew older. Fish and amphipods were brought to chicks during the day, whereas adults brought Antarctic krill at sunrise and sunset. Both the duration of the feeding trips and the number of trips per foraging bout varied according to the type of prey caught. Preliminary information suggests that, among other causes, the foraging strategy is strongly influenced by the predation pressure of skuas on chicks. Results are compared with the only two previous study on the diet of the Antarctic Tern at the South Shetland Islands.     

Biophysical Characterisation of Neuroglobin of the Icefish, a Natural Knockout for Hemoglobin and Myoglobin. Comparison with Human Neuroglobin

The Antarctic icefish Chaenocephalus aceratus lacks the globins common to most vertebrates, hemoglobin and myoglobin, but has retained neuroglobin in the brain. This conserved globin has been cloned, over-expressed and purified. To highlight similarities and differences, the structural features of the neuroglobin of this colourless-blooded fish were compared with those of the well characterised human neuroglobin as well as with the neuroglobin from the retina of the red blooded, hemoglobin and myoglobin-containing, closely related Antarctic notothenioid Dissostichus mawsoni. A detailed structural and functional analysis of the two Antarctic fish neuroglobins was carried out by UV-visible and Resonance Raman spectroscopies, molecular dynamics simulations and laser-flash photolysis. Similar to the human protein, Antarctic fish neuroglobins can reversibly bind oxygen and CO in the Fe²⁺ form, and show six-coordination by distal His in the absence of exogenous ligands. A very large and structured internal cavity, with discrete docking sites, was identified in the modelled three-dimensional structures of the Antarctic neuroglobins. Estimate of the free-energy barriers from laser-flash photolysis and Implicit Ligand Sampling showed that the cavities are accessible from the solvent in both proteins.Comparison of structural and functional properties suggests that the two Antarctic fish neuroglobins most likely preserved and possibly improved the function recently proposed for human neuroglobin in ligand multichemistry. Despite subtle differences, the adaptation of Antarctic fish neuroglobins does not seem to parallel the dramatic adaptation of the oxygen carrying globins, hemoglobin and myoglobin, in the same organisms.     

Benthic hydroids (Cnidaria: Hydrozoa) from the Bransfield Strait area (Antarctica) collected by Brazilian expeditions,with the description of a new species

A total of 36 species of benthic hydroids, belonging to nine families and 16 genera, were found in the hydroid collection gathered during the Brazilian Antarctic expeditions PROANTAR III and IV. Seven of the species were identified only to generic level. There is a clear dominance of the subclass Leptothecatae with 33 species. By far the most diversified family was the Sertulariidae, with 16 species (44%). Symplectoscyphus with eight species, including Symplectoscyphus magnificus sp. nov., is the most diversified genus. Almost 70% of the species diversity is restricted to just six genera (38%). Sixty-eight percent of the species is Antarctic endemics and 86% is restricted to Antarctic or Antarctic/sub-Antarctic waters. Eudendrium antarcticum and Amphisbetia operculata are recorded for the first time from Antarctic waters.