Jerzy Smykla

Tardigrada of the Revdalen (Spitsbergen) with the descriptions of two new species: Bryodelphax parvuspolaris (Heterotardigrada) and Isohypsibius coulsoni (Eutardigrada)

Despite a century long history of research, tardigrade fauna of the Svalbard Archipelago remains poorly known. In order to deepen our knowledge of tardigrade biodiversity in the Arctic, we collected forty-one moss and lichen samples from the Revdalen and on the south-east slopes of the Rotjesfjellet (Spitsbergen, Svalbard Archipelago) in June 2010. In these samples, twenty-five tardigrade species were found, including two new for science: Bryodelphax parvuspolaris sp. nov. and Isohypsibius coulsoni sp. nov. B. parvuspolaris sp. nov. belongs to the weglarskae group but differs from all other species of the group by a unique configuration of ventral plates. I. coulsoni sp. nov. differs from the most similar species I. ceciliae Pilato and Binda, 1987 mainly by the absence of ventral sculpture. Two additional species, Milnesium asiaticum Tumanov, 2006 and Diphascon (Adropion) prorsirostre Thulin, 1928, are recorded from the Svalbard Archipelago for the first time.

Low-temperature limitation of primary photosynthetic processes in Antarctic lichens Umbilicaria antarctica and Xanthoria elegans

Temperature response curves of chlorophyll a fluorescence parameters were used to assess minimum sub-zero temperature assuring functioning of photosynthetic photochemical processes in photosystem II (PS II) of Antarctic lichens. Umbilicaria Antarctica and Xanthoria elegans were measured within the temperature range from −20 to +10°C by a fluorometric imaging system. For potential (FV/FM) and actual (ΦII) quantum yields of photochemical processes the minimum temperature was found to be between −10 and −20°C. Non-photochemical quenching (NPQ) of absorbed excitation energy increased with temperature drop reaching maximum NPQ at −15°C. Image analysis revealed intrathalline heterogeneity of chlorophyll a fluorescence parameters with temperature drop. Temperature response of ΦII exhibited an S-curve with pronounced intrathalline differences in X. elegans. The same relation was linear with only limited intrathalline difference in U. antarctica. The results showed that Antarctic lichen species were well adapted to sub-zero temperatures and capable of performing primary photosynthesis at −15°C.

Diversity and distribution of tardigrades in soils of Edmonson Point (Northern Victoria Land, continental Antarctica)

This work contributes to the knowledge on distribution, diversity and ecology of the Antarctic soil biota. Different soil habitats from several ice-free coastal sites were sampled along the Victoria Land across 7° of latitude from 71° to 78°S during five austral summer seasons between 2003/04 and 2011/12. In this paper we report preliminary data on soil tardigrades (water bears) from Edmondson Point, Northern Victoria Land. Tardigrades were found to be present in 23 of the 41 examined soil samples (56%). Their presence was associated exclusively with soil samples collected from bryophytes communities and under cyanobacterial mats, whereas they were completely absent in fellfield and ornithogenic soils. Tardigrades were least numerous among all soil micrometazoans, their abundance in the positive samples was very variable and ranged from 3 to 1824 individuals per 100 g of soil DW. High water content seemed to be the major factor determining occurrence of tardigrades in the soils investigated. On the other hand low water content and toxic compounds from penguin guano seemed to act as a strong constraint on their existence in the Antarctic soils. Taxonomic evaluation of the extracted tardigrades revealed presence of only two species belonging to class Eutardigrada: Acutuncus antarcticus (Richters, 1904) and Milnesium antarcticum Tumanov, 2006. While A. antarcticus has already been reported previously as the most widespread and abundant tardigrade across the Victoria Land, the information on M. antarcticum is novel, both for Victoria Land and the continental Antarctica.

The lichen genus Umbilicaria 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.

Distribution and diversity of Tardigrada along altitudinal gradients in the Hornsund, Spitsbergen (Arctic)

Two transects were established and sampled along altitudinal gradients on the slopes of Ariekammen (77°01′N; 15°31′E) and Rotjesfjellet (77°00′N; 15°22′E) in Hornsund, Spitsbergen. In total 59 moss, lichen, liverwort and mixed moss–lichen samples were collected and 33 tardigrade species of Hetero- and Eutardigrada were found. The α diversity ranged from 1 to 8 per sample; the estimated number of species based on all analysed samples was 52±17 for the Chao 2 estimator and 41 for the incidence-based coverage estimator. According to the results of detrended canonical correspondence analysis, altitude and type of substratum were the most important factors influencing tardigrade communities in the investigated area. Macrobiotus crenulatus, M. hufelandi hufelandi and Hypsibius pallidus dominated in the lower elevations, whereas Echiniscus wendti and E. merokensis merokensis prevailed in samples from higher plots. Macrobiotus islandicus islandicus was collected most often from mosses collected from rock whereas Isohypsibius coulsoni from mosses collected from soil. Analyses of covariance were employed to test for differences in species richness between the transects in relation to altitude. Contrary to expectations, there were significant differences in species richness between the transects, but richness was not significantly related to altitude. Interestingly, significant effects of colonies of seabirds, little auk (Alle alle), on the tardigrades communities were detected. Additionally, in one of the samples first ever males of Milnesium asiaticum were found. Their measurements and microphotographs are provided herein.

Comparative phylogeography of three trematomid fishes reveals contrasting genetic structure patterns in benthic and pelagic species

Population genetics patterns of marine fish in general and of Southern Ocean fish in particular range from virtual panmixia over ocean-wide scale to deeply fragmented populations. However the causes underlying these different patterns are not properly understood. In this paper, we tested the hypotheses that population connectivity is positively related to a combination of life history traits, namely duration of pelagic larval period and the tendency towards pelagic life style in the adulthood. To do so, we analysed the variability of six microsatellite and one mitochondrial marker (cytochrome b) in three Southern Ocean fish species (Trematomus newnesi, Trematomus hansoni and Trematomus bernacchii). They share a recent common ancestor but notably differ in their duration of pelagic larval period as well as pelagic versus benthic lifestyle. We sampled over a range of more than 5000 km for all three species and used a number of population genetics tools to investigate past and contemporary levels of connectivity. All species experienced population fluctuations, but coalescent simulations suggested that contemporary populations are in migration-drift equilibrium. Although global F(ST) values were rather low, a significant population structure separated the High-Antarctic from the Peninsular regions in all species. The level of genetic differentiation was much lower in the pelagic versus benthic species. Present data suggest that past and present genetic structuring in the Southern Ocean are indeed related with the ecological traits of Antarctic fish, however the relative importance of individual factors remains unclear.

Antarctic bdelloid rotifers: diversity, endemism and evolution

Antarctica is an isolated continent whose conditions challenge the survival of living organisms. High levels of endemism are now known in many Antarctic organisms, including algae, tardigrades, nematodes and microarthropods. Bdelloid rotifers are a key, widespread and abundant group of Antarctic microscopic invertebrates. However, their diversity, regional distribution and endemism have received little attention until recently. We provide the first authoritative review on Antarctic Bdelloidea, based on published data and new collections. Our analysis reveals the extreme levels of bdelloid endemism in Antarctica. Sixty-six bdelloid morphospecies are now confirmed from the continent, and 83–91 putative species are identified using molecular approaches (depending on the delimitation method used). Twelve previously unknown species are described based on both morphology and molecular analyses. Molecular analyses indicate that only two putative species found in Antarctica proved to be truly cosmopolitan. The level of endemism based on the available data set (95%) is higher than that in any other continent, with many bdelloid species occurring only in maritime or continental Antarctica. These findings are consistent with the long-term presence of Bdelloidea in Antarctica, with their considerable isolation facilitating intraregional radiation, providing further evidence that does not support the microbial global ubiquity hypothesis that “everything is everywhere.”

The first record of a rare marine tardigrade, Halobiotus crispae Kristensen, 1982 (Eutardigrada: Hypsibiidae), from the Svalbard Archipelago

A rare marine tardigrade Halobiotus crispae Kristensen, 1982 was found abundant in intertidal flats at Josephbukta, Bellsund fiord, West Spitsbergen. This is the first record of this species from the Svalbard Archipelago. So far, the species has been found only in seven other localities in the northern hemisphere (between 56° and 69°N). The present record greatly extends the known geographical range to the north and also indicates a much wider distribution of the species than formerly reported. Moreover, a potential indicative character of this species and of the study area in monitoring climatic changes is discussed.

Seabird guano boosts body size of water bears (Tardigrada) inhabiting the arctic tundra

Abstract(1) During the Arctic summer, little auks (Alle alle) deposit considerable amounts of guano on land. Ecosystems subsidised in nutrients are known to hold greater biodiversity and to produce grander biomass of plants and animals compared with areas where seabirds do not nest. (2) The aim of this study was to look into the relationship between guano fertilisation and body size of invertebrates inhabiting tundra. (3) The specimens of Macrobiotus islandicus islandicus Richters, 1904, a tardigrade dwelling in mosses and lichens of the Arctic, from six different populations from Spitsbergen (Hornsund fjord) were measured. Tardigrades were collected from areas different in terms of seabird guano effects on the tundra ecosystem. An overall body size index for tardigrades was calculated using a principal component analysis. (4) Here, we show that the body size of M. i. islandicus is larger in vicinities of the little auk colonies than in areas devoid of bird nesting sites. (5) Given that fitness of many invertebrates is positively correlated with their condition, our study underlines the ecological importance of a side effect of seabirds biology—the transfer of nutrients from the sea to the land.

Soil tardigrades from the Antarctic Peninsula with a description of a new species and some remarks on the genus Ramajendas (Eutardigrada: Isohypsibiidae)

In thirteen (mostly soil) mixed samples, collected from nine localities on the Antarctic continent and some of the neighbouring islands, 788 specimens and 32 eggs of tardigrades were found. In total, five species were identified: Acutuncus antarcticus, Echiniscus jenningsi , Diphascon ( D. ) victoriae , Hypsibius dujardini and Ramajendas dastychi sp. nov. A. antarcticus was the most abundant (nearly 90% of all specimens) and was the prevailing taxon found in the majority of locations. R. dastychi sp. nov. is the fourth species described in the exclusively Antarctic/sub-Antarctic genus. The new species differs from all other congeners by the presence of four gibbosities on the caudo-dorsal cuticle (configuration II:2–2) and also by some morphometric characters. In this paper we also briefly discuss the taxonomy and zoogeography of the genus Ramajendas .