The polar lichens Caloplaca darbishirei and C. soropelta highlight the direction of bipolar migration

A proper phytogeographic affiliation of Antarctic lichen species has become feasible using molecular phylogeographic methods. Caloplaca citrina is a heterogeneous taxon including several species which occurs in polar regions and is common in Antarctica. Collections of C. citrina from the Antarctic were revised using morphological, anatomical and molecular characters (ITS). They were found to belong to two species: Caloplaca darbishirei (C.W. Dodge & G.E. Baker) Cretz. and C. soropelta (E.S. Hansen, Poelt & S?chting) S?chting. The molecular phylogeny showed them to be sister species, but well separated. Morphological and chemical characters, ecology and distribution of the species are discussed. C. darbishirei is the most common species in the Antarctic, and it is so far known only from Antarctica and Southern South America. C. soropelta, reported here as new to South America, is a bipolar species with all close relatives in the Southern Hemisphere; it is therefore most likely that the species colonized the Arctic from the south. C. citrina s. str. is not confirmed to occur in Antarctica. The study emphasizes the suitability of genotyping for understanding the taxonomy and phylogeography of bipolar lichens.     

The genus Stauroneis (Bacillariophyceae) in the Antarctic region

Aim To provide a detailed biogeography of the diatom genus Stauroneis in the Antarctic and sub‐Antarctic regions and to establish the biogeographical relationships between the different constituent locations to test the application of a precise and refined taxonomy in generating accurate polar biogeographies. Location The Antarctic and sub‐Antarctic region comprising the islands South Georgia, Crozet, Kerguelen, Marion, Heard and the Antarctic Peninsula. Methods Diatom samples from different habitats in a large part of the sub‐Antarctic and Antarctic region were investigated for their Stauroneis content. Presence/absence data were investigated using Sørensen's similarity index. An additional 500 samples from Arctic locations were used to provide a bipolar comparison. Using reliable literature data, gaps in the distribution of the Stauroneis taxa were filled. Results The Stauroneis flora of the Antarctic and sub‐Antarctic regions is quite distinct from its Arctic equivalent, with only five species (out of 60) common to both areas. Within the (sub‐)Antarctic group, the islands of the Indian Ocean have the most diverse Stauroneis composition, which is clearly separated from the rest of the region. The South Georgia Stauroneis composition has some affinities with the Antarctic Peninsula but the latter has far fewer species. These results are in clear contrast to older data showing no biogeographical difference between the Arctic and Antarctic regions. Main conclusions Using only a single genus, a clear biogeography of the (sub‐)Antarctic region can be produced that separates the Indian Ocean islands from other sampling locations. When based on a precise taxonomy, biogeographical relationships between locations in the region become much more reliable. Contrary to previous work, there is almost no similarity in the diatom floras of the Arctic and Antarctic regions.     

THE GENUSFULGENSIAA. MASSAL. & De NOT., A DIVERSE GROUP IN THE TELOSCHISTACEAE

The morphology and the anatomy of the 13 species presently included in the genusFulgensiawere surveyed.Caloplaca aureaandC. paulii, two species regarded as closely related toFulgensiaby earlier authors, were also included in the study.Fulgensiawas found to exhibit a great variation in both morphology and anatomy. The differences in size, shape and septation of the spores, in the anatomy of cortex and exciple, and in the gross morphology, will presumably motivate a different taxonomic treatment in the future. A tentative separation of the species into four different groups is proposed here. Group A comprisesF. australisandF. chanousiae, which appear close to species inCaloplacasect.Gasparrinia.Groups B and C, each comprises one species,F. schistidiiandF. canariensisrespectively and group D comprises the remaining nine species, including the type speciesF. fulgens. The last group may be further split by a more detailed investigation. The present separation ofFulgensiainto two subgenera cannot be regarded as taxonomically sound. The genus is probably polyphyletic and the different groups are probably related to different groups within the large genusCaloplaca.     

In situ monitoring of microclimate and metabolic activity in lichens from Antarctic extremes: a comparison between South Shetland Islands and the McMurdo Dry Valleys

Lichens are the dominant organisms in terrestrial Antarctic ecosystems and show a decline in species number, coverage, and growth rate from the maritime Antarctic (62°S) to the McMurdo Dry Valleys (78°S). While Livingston Island (maritime Antarctica) is a hot spot for lichen biodiversity, the McMurdo Dry Valleys (continental Antarctica) are known as one of the most extreme environments for life. Previous studies suggest the biodiversity gradient to be linked to water availability acting through length of active period, but no activity data are available for the Dry Valleys. The work presented here compares metabolic activity of lichens at Livingston Island and the Dry Valleys for 4½ months from continuous monitoring that involves concurrent measurements of chlorophyll fluorescence and microclimate. The latitudinal comparison involves two contrasting habitats for plant physiological activity and microclimate. Two species of the foliose genus Umbilicaria were monitored in both regions plus one sample of the crustose Caloplaca in the Dry Valleys. The results showed a very large difference in the duration of activity over the monitoring period, and this supports the different coverage, species abundance, and growth rates already reported for lichens between both regions. Despite this large difference in activity, and in habitat conditions, analysis of the activity behaviour of the two Umbilicaria species shows interesting common features, while the crustose Caloplaca had additional strategies to improve hydration. This offers one explanation for the abundance of crustose lichens inside the Valleys, indicating better adaptation strategies to a polar desert.     

Genetic differentiation between Arctic and Antarctic monothalamous foraminiferans

Monothalamous (single-chambered) foraminifers are a major component of the benthic meiofauna in high latitude regions. Several morphologically similar species are common in the Arctic and Antarctic. However, it is uncertain whether these morphospecies are genetically identical, or whether their accurate identification is compromised by a lack of distinctive morphological features. To determine the relationship between Arctic and Antarctic species, we have compared SSU rDNA sequences of specimens belonging to four morphotaxa: Micrometula, Psammophaga, Gloiogullmia, and one morphospecies Hippocrepinella hirudinea from western Svalbard (Arctic) and McMurdo Sound (Antarctic). Wherever possible, we include in our analyses representatives of these taxa from the deep Arctic and Southern Oceans, as well as from Northern European fjords. We found that in all cases, the bipolar populations were clearly distinct genetically. As expected, Arctic specimens were usually more closely related to those from Northern Europe than to their Antarctic representatives. The deep-sea specimens from Weddell Sea branched as a sister to the McMurdo Sound population, while those from the Arctic Ocean clustered with ones from Norwegian fjords. Our study has revealed a high number of cryptic species within each of the examined genera, and demonstrates the unexplored potential of monothalamous foraminifers for use as a tool to evaluate the origin and biogeography of polar meiofauna.     

Caloplaca sect.Xanthoriella,sect. nov.: Untersuchungen über die „Xanthoria lobulata-Gruppe“ (Lichenes,Teloschistaceae)

Reexamination ofXanthoria persica, X. polycarpoides, X. lobulata gave evidence, that the thalli of these species are devoid of a lower cortex and rhizinae. Therefore, they do not fit the definition of the genusXanthoria and are transferred toCaloplaca (under the new sectionXanthoriella) asCaloplaca persica, C. polycarpoides, andC. boulyi, respectively. — Details on development, anatomical structure, ecology and distribution are presented.

     

CALOPLACA MARITIMA,A MISUNDERSTOOD SPECIES IN WESTERN EUROPE

Caloplaca maritimaB. de Lesd. is a marine to maritime species occurring in western Europe. It was first described as a variety ofC. citrina(Hoffm.) Th. Fr., but in 1953 was transferred to specific level. Since thenC. maritimahas been more or less forgotten and/or misunderstood, mainly due to confusion withC. ruderum(Malbr.) J. R. Laundon,C. interfulgens(Nyl.) J. Steiner, andC. marina(Wedd.) Zahlbr. The present paper reports on the existence ofC. maritimaand clarifies its status in relation toC. marinaand to other related species. A map of the presently known distribution is presented and the species is depicted. Lectotypes forCaloplaca citrinavar.maritimaC. citrinavar.maritimaf.laevigataare selected.     

Poles Apart: The “Bipolar” Pteropod Species Limacina helicina Is Genetically Distinct Between the Arctic and Antarctic Oceans

The shelled pteropod (sea butterfly) Limacina helicina is currently recognised as a species complex comprising two sub-species and at least five “forma”. However, at the species level it is considered to be bipolar, occurring in both the Arctic and Antarctic oceans. Due to its aragonite shell and polar distribution L. helicina is particularly vulnerable to ocean acidification. As a key indicator of the acidification process, and a major component of polar ecosystems, L. helicina has become a focus for acidification research. New observations that taxonomic groups may respond quite differently to acidification prompted us to reassess the taxonomic status of this important species. We found a 33.56% (±0.09) difference in cytochrome c oxidase subunit I (COI) gene sequences between L. helicina collected from the Arctic and Antarctic oceans. This degree of separation is sufficient for ordinal level taxonomic separation in other organisms and provides strong evidence for the Arctic and Antarctic populations of L. helicina differing at least at the species level. Recent research has highlighted substantial physiological differences between the poles for another supposedly bipolar pteropod species, Clione limacina. Given the large genetic divergence between Arctic and Antarctic L. helicina populations shown here, similarly large physiological differences may exist between the poles for the L. helicina species group. Therefore, in addition to indicating that L. helicina is in fact not bipolar, our study demonstrates the need for acidification research to take into account the possibility that the L. helicina species group may not respond in the same way to ocean acidification in Arctic and Antarctic ecosystems.     

Heterolobosean amoebae from Arctic and Antarctic extremes: 18 novel strains of Allovahlkampfia,Vahlkampfia and Naegleria

The diversity of heterolobosean amoebae, important members of soil, marine and freshwater microeukaryote communities in the temperate zones, is greatly under-explored in high latitudes. To address this imbalance, we studied the diversity of this group of free-living amoebae in the Arctic and the Antarctic using culture dependent methods. Eighteen strain representatives of three heterolobosean genera, Allovahlkampfia Walochnik et Mulec, 2009 (1 strain), Vahlkampfia Chatton et Lalung-Bonnaier, 1912 (2) and Naegleria Alexeieff, 1912 (15) were isolated from 179 samples of wet soil and fresh water with sediments collected in 6 localities. The Allovahkampfia strain is the first representative of the genus from the Antarctic; 14 strains (7 from the Arctic, 7 from the Antarctic) of the highly represented genus Naegleria complete the ‘polar’ cluster of five Naegleria species previously known from the Arctic and Sub-Antarctic regions, whereas one strain enriches the ‘dobsoni’ cluster of Naegleria strains of diverse origin. Present isolations of Naegleria polaris De Jonckheere, 2006 from Svalbard, in the Arctic and Vega Island, in the Antarctic and N. neopolaris De Jonckheere, 2006 from Svalbard and Greenland in the Arctic, and James Ross Island, the Antarctic demonstrate their bipolar distribution, which in free-living amoebae has so far only been known for Vermistella Morand et Anderson, 2007.     

Invited review: climate change impacts in polar regions: lessons from Antarctic moss bank archives

Mosses are the dominant plants in polar and boreal regions, areas which are experiencing rapid impacts of regional warming. Long‐term monitoring programmes provide some records of the rate of recent climate change, but moss peat banks contain an unrivalled temporal record of past climate change on terrestrial plant Antarctic systems. We summarise the current understanding of climatic proxies and determinants of moss growth for contrasting continental and maritime Antarctic regions, as informed by 13C and 18O signals in organic material. Rates of moss accumulation are more than three times higher in the maritime Antarctic than continental Antarctica with growing season length being a critical determinant of growth rate, and high carbon isotope discrimination values reflecting optimal hydration conditions. Correlation plots of 13C and 18O values show that species (Chorisodontium aciphyllum / Polytrichum strictum) and growth form (hummock / bank) are the major determinants of measured isotope ratios. The interplay between moss growth form, photosynthetic physiology, water status and isotope composition are compared with developments of secondary proxies, such as chlorophyll fluorescence. These approaches provide a framework to consider the potential impact of climate change on terrestrial Antarctic habitats as well as having implications for future studies of temperate, boreal and Arctic peatlands. There are many urgent ecological and environmental problems in the Arctic related to mosses in a changing climate, but the geographical ranges of species and life‐forms are difficult to track individually. Our goal was to translate what we have learned from the more simple systems in Antarctica, for application to Arctic habitats.     

Colonization by lichens and the development of lichen-dominated communities in the maritime Antarctic

Three long-term studies of lichen growth and colonization have been undertaken at Signy Island, South Orkney Islands, in the maritime Antarctic. Small individual thalli of several crustose species and uncolonized plots on 12 fresh rock surfaces were photographically monitored at intervals of 3–4 years over a period of up to 20 years. The development of Ochrolechia frigida colonies on a regenerating moss bank, recently uncovered by a receding glacier, was similarly monitored. The results indicate that many lichens growing in sites enriched by nitrogenous compounds derived from populations of sea birds, have relatively rapid colonization and growth rates. Mean percentage increase in thallus area can be as high as 15–32% per annum in some nitrophilous saxicolous species (e.g. Acarospora macrocyclos, Xanthoria elegans and species of Buellia and Caloplaca), but as low as 0·4–4% in nitrophobous species (Lecanora physciella, Lecidea sp., Rhizocarpon geographicum). Umbilicaria antarctica and Usnea antarctica also yielded data indicating high growth rates, with colonist plants reaching several centimetres after 20 years. Colonization by mixed assemblages of lichens of new rock surfaces can attain 40→90% cover after 20 years in nutrient-enriched sites, and even 20–25% in non-biotically influenced sites. Colonization by or increase in extant O. frigida on the regenerating moribund moss bank was also quite rapid. It is suggested that the ~exceptionally large thalli of several lichen species and the locally extensive dense lichen fellfield communities in the maritime Antarctic may be much younger than previously supposed.     

Mycorrhizas and dark septate root endophytes in polar regions

We review the distributions and functions of mycorrhizas and dark septate root endophytes in polar regions. Arbuscular mycorrhizas (AM) are present in the Arctic and Antarctic to 82 °N and 63 °S, respectively, with fine endophyte being the dominant form of AM in roots at higher latitudes. Ecto- (ECM) and ericoid (ERM) mycorrhizas both occur in the Arctic to 79 °N, owing to the presence of species of Salix, Dryas, Vaccinium and Cassiope to this latitude. ECM and ERM are not present in Antarctic ecosystems, owing to an absence of suitable hosts. Arbutoid and orchid mycorrhizas are infrequent in the Arctic, whilst the latter are present at one location in the sub-Antarctic. Data from studies of AM, ECM and ERM colonisation along a latitudinal transect through the Arctic indicate that the frequency of plant species not colonised by mycorrhizas increases at higher latitudes, largely owing to an increase in non-mycorrhizal and a decrease in obligately mycorrhizal plant families at more northerly locations. A separate group of root- and rhizoid-associated fungi, the dark septate root endophytes (DSE), are widespread to 82 °N and 77 °S, and are apparently more frequent than mycorrhizal fungi in polar regions. The functions of DSE are largely unclear, but studies suggest beneficial effects on plant growth under defined conditions. We advocate further research into the effects of DSE on their host plants in polar regions.     

Contributions to the Caloplaca flora of the western Antarctic region

Fourteen species of the lichen genus Caloplaca are recorded from the western Antarctic region and described morphologically and anatomically, viz.: C. ammiospila, C. approximata, C. athallina, C. cirrochrooides, C. citrina, C. isidioclada, C. lucens, C. millegrana, C. regalis, C. sublobulata, C. tenuis, C. aff. anchon-phoeniceon. Type specimens of critical species have been studied. A key is provided to the species. Caloplaca ammiospila and C. approximata are reported as new to the Antarctic region.     

Zwergstrauchige Arten der FlechtengattungCaloplaca

The frutescent species of the lichen genusCaloplaca are usually united in sect.Thamnoma, but they do not form a natural group. They are derived from different species groups within sect.Gasparrinia from different parts of the world, presumable from species having scleroplectenchymes in cortex and medulla. The algal cells are concentrated between the scleroplectenchymatic strands in large and dense groups, from where medullary plectenchyme extends to the cortex and forms characteristic pseudocyphellae there.—Most of the species seem to be ornithocoprophilous; they grow on rocks along marine coasts where much fog is induced by cold currents.—Caloplaca cribrosa is endemic in Tasmania and New Zealand,C. regalis and the doubtfulC. ambitiosa belong to the antarctic element.C. fragillima from central Chile seems to be propagated by thallus fragments.C. coralloides andC. thamnodes are endemic to California and Baja California respectively.C. cladodes from the Rocky Mountains deviates in many characteristics from the other species i.a. by it different ontogenetic development, reduced spore septum, and cementing amyloid polysaccharides within the scleroplectenchymatic strands. The African species are characterized by their distinctly dorsiventral lobes and usually possess oil cells in some of the paraphyses.Caloplaca bonae-spei, C. fragillima andC. thamnodes are new to science.

     

Molecular analysis of fungal diversity associated with three bryophyte species in the Fildes Region, King George Island, maritime Antarctica

The fungal communities associated with three bryophytes species (the liverwort Barbilophozia hatcheri, the mosses Chorisodontium aciphyllum and Sanionia uncinata) in the Fildes Region, King George Island, maritime Antarctica, were studied using clone library analysis. Fungal communities showed low diversity; the 680 clones belonged to 93 OTUs. Of these, 78 belonged to the phylum Ascomycota, 13 to the phylum Basidiomycota, 1 to the phylum Zygomycota, and 1 to an unknown phylum. Among the OTUs, the most common orders in the Ascomycota were Helotiales (42 OTUs) and Chaetothyriales (14 OTUs) and the most common orders in the Basidiomycota were Sebacinales (3 OTUs) and Platygloeales (3 OTUs). Most OTUs clustered within clades that contained phylotypes identified from samples in Antarctic or Arctic ecosystems or from bryophytes in other ecosystems. In addition, we found that host-related factor may shape the fungal communities associated with bryophytes in this region. This is the first systematic study of the fungal community in Antarctic bryophytes to be performed using culture-independent method and the results may improve understanding of the endophytic fungal evolution and ecology in the Antarctic ecosystem.     

The lichen genus <Emphasis Type="Italic">Umbilicaria</Emphasis> from the neighbourhood of Admiralty Bay (King George Island,maritime Antarctic), with a proposed new key to all Antarctic taxa

This paper documents the occurrence of the genus Umbilicaria in the neighbourhood of Admiralty Bay on King George Island in the maritime Antarctic. Nine species are reported from the area surveyed, with Umbilicaria kappeni being reported from King George Island for the first time. The occurrence of U. aprina, U. cristata and U. umbilicarioides on the island is confirmed and that of U. aprina is its first documented record from the maritime Antarctic. Fertile specimens of U. umbilicarioides are recorded for the first time from Antarctica. The area around Admiralty Bay seems to be one of the Antarctic regions with the highest diversity of Umbilicaria species. The diagnostic characters and distribution of each species are discussed. An updated key for identification of all the Antarctic species of the genus is provided.     

Two species of swimming crabs of the genus Achelous (Crustacea,Brachyura): environmental requirements determining the niche

Some holoplanktonic species are cosmopolitan and have continuous distribution in the world’s oceans. For most of these species it is not clear whether there is unhampered gene flow between far distant populations or they represent a complex of cryptic species. In the present study we investigated genetic diversity of the cosmopolitan chaetognath Eukrohnia hamata in order to identify its spatial structure. DNA-barcode fragment of the mitochondrial COI gene was determined and analyzed for E. hamata specimens collected in the Arctic Ocean, Atlantic Ocean, and Atlantic sector of the Southern Ocean. Five lineages were determined by the phylogenetic analysis with robust statistical support. Three lineages: Antarctic (Eh-1), Subantarctic (Eh-2), and Arctic (Eh-3) had significant genetic differences and were geographically separated. Two other lineages: Eh-4 and Eh-5, that had the smallest genetic difference, were observed together in tropical waters, but they were geographically separated from the other lineages. We suppose that geographical distribution of most of the E. hamata lineages is shaped by the large-scale oceanic fronts, considered as biogeographic boundaries for numerous zooplankton species. Genetic homogeneity of Arctic, Subantarctic, and Antarctic lineages was also shown, each within its regions of inhabit.     

Ciliate biogeography in Antarctic and Arctic freshwater ecosystems: endemism or global distribution of species?

Ciliate diversity was investigated in situ in freshwater ecosystems of the maritime (South Shetland Islands, mainly Livingston Island, 63 degrees S) and continental Antarctic (Victoria Land, 75 degrees S), and the High Arctic (Svalbard, 79 degrees N). In total, 334 species from 117 genera were identified in both polar regions, i.e. 210 spp. (98 genera) in the Arctic, 120 spp. (73 genera) in the maritime and 59 spp. (41 genera) in the continental Antarctic. Forty-four species (13% of all species) were common to both Arctic and Antarctic freshwater bodies and 19 spp. to both Antarctic areas (12% of all species). Many taxa are cosmopolitans but some, e.g. Stentor and Metopus spp., are not, and over 20% of the taxa found in any one of the three areas are new to science. Cluster analysis revealed that species similarity between different biotopes (soil, moss) within a study area was higher than between similar biotopes in different regions. Distinct differences in the species composition of freshwater and terrestrial communities indicate that most limnetic ciliates are not ubiquitously distributed. These observations and the low congruence in species composition between both polar areas, within Antarctica and between high- and temperate-latitude water bodies, respectively, suggest that long-distance dispersal of limnetic ciliates is restricted and that some species have a limited geographical distribution.     

Changes in the lichen biota of the Lions Rump area,King George Island,Antarctica, over the last 20 years

Climate changes observed in recent years in the maritime Antarctic have affected the tundra vegetation, including plant communities in which lichens are a dominant component. The results of comparative studies (1988 and 1990 vs. 2007 and 2008) on the dynamics of the lichen biota within the Antarctic Specially Protected Area No. 151 (King George Island, Antarctica) minimally influenced by human impact, are presented. This long-term experiment is aimed at determining the trends and rate of changes on lichen biota induced by climate warming and rapid deglaciation. The most significant changes affecting the lichen biota have taken place in the forefield of a glacier and on the young moraines where in the second period of studies three species (Polyblastia gothica, Thelenella kerguelena, Thelocarpon cyaneum) were not refound. There was also a reduction in the number of other sites for some species (e.g. Leptogium puberulum, Staurothelle gelida) caused by substrate desiccation. On the other hand, there was an increase in the range of pioneering species (e.g. Bacidia chrysocolla, Caloplaca johnstonii, Candelariella aurella, Lecanora dispersa) on young moraines recently uncovered by the retreating glacier. The smallest changes were observed on the cliff rocks near penguin colonies.