Early Cretaceous mammals of Western Siberia: 2. Tegotheriidae

New specimens of the tegotheriid docodont Sibirotherium rossicum Maschenko et al., 2003, including a maxillary fragment with two posterior teeth, an isolated upper molar, and mandibular fragments with teeth from the Early Cretaceous Shestakovo locality are described. The dental formula of Sibirotherium is I_{1 + ?}C1P₆M_6?. The upper molars of Sibirotherium, with two main labial and three lingual cusps, are convergently similar to the molars of tribosphenic mammals. In the dentary, the symphysis is short and Meckel’s groove is reduced. Sibirotherium is similar in the structure of lower teeth to Tegotherium from the Upper Jurassic of Mongolia; it is the latest known representative of Docodonta.     

Simulating the development of peat bogs

Summary A dynamic model is developed which simulates changes in peat bogs on different kinds of slopes. The relationships between the elements of the model which include bog plants, fen plants, water, peat and nutrients, are defined based on data from an earlier study of vegetation in the Rothenthurm area in Switzerland, and from published sources.The model is tested for its performance on three types of slope, starting development at a hypothetical state with low amounts of all variables. The development of bogs is traced until a stable state is reached at equilibrium.It is evident from the results that the establishment of a mature stable system takes longest on the flat slope. On all three slopes the peat layer reaches its maximum value before the equilibrium is reached at a slightly reduced peat level. As were observed in the fied, most slope types do not allow a peat bog to persist long under the local climatical conditions, but changes are forced in the vegetation toward a fen type with higher nutrient supply. It was however possible to simulate a stable peat bog when the slope was flat enough (type C in main text). The results of simulation reproduced with reasonable accuracy the shape of the bogs investigated in the field, the abundance of bog and fen plant species, the ground water table, the thickness of peat and the state of nutrient concentrations in the site. The model is rendered to have minimum complexity by assumptions, described in the main text, to reproduce only those properties of peat bogs that were considered primary in importance in the field. The extent to which the model can help to better understand the natural system is discussed.A version of the model described in this paper was developed by the author at the Institute of Geobotany, Swiss Federal School of Technology, Zürich, in 1975–1976. The author expresses his thanks to Prof. Dr. E. Landolt, Director of the Department.     

Methane emissions from fen,bog and swamp peatlands in Quebec

A static chamber technique was used weekly from spring thaw to winter freezing to measure methane emissions from 10 sites representing subarctic fens and temperate swamps and bogs. Rates of < 200 mg CH₄ m^–2 d^–1 were recorded in subarctic fens: within-site emissions were primarily controlled by the evolution of the peat thermal regime, though significant releases during spring thaw were recorded at some sites. Between subarctic fens, topography and water table elevation were important controls on methane emissions, with the general sequence: pool = horizontal fen> string. Emission rates from the 2 swamp sites were lower (< 20 mg CH₄ m^–2 d^–1 ), except during the spring thaw and when the sites were saturated. The low water table ( < 80 cm depth) in abnormally dry years reduced emission rates; rates were also low from a swamp site which had been drained and cleared of vegetation for horticulture. Methane emission rates were also low (< 5 mg CH₄ m^–2 d^–1) from 2 ombrotrophic bog sites. Laboratory measurements of rates of methane production under anaerobic conditions and methane consumption under aerobic conditions revealed that production rates were generally highest in the surface layers (0 to 2.5 cm depth); production was high in the fens and very low in the bogs. The swamp samples were able to produce methane under anaerobic conditions, but were also able to consume methane under aerobic conditions. Annual methane emission rates are estimated to be 1 to 10 g CH₄ m^–2 from the fens, 1 to 4 g CH4 m^–2 from the swamps and <0.2 g CH₄ m^–2 from the bogs and drained swamp.     

North American approach to the restoration of Sphagnum dominated peatlands

Sphagnum dominated peatlands do not rehabilitate well after being cutover (mined) for peat and some action needs to be taken in order to restore these sites within a human generation. Peatland restoration is recent and has seen significant advances in the 1990s. A new approach addressing the North American context has been developed and is presentedin this paper. The short-term goal of this approach is to establish a plant cover composed of peat bog species and to restore a water regime characteristic of peatland ecosystems. The long-term objective is to return the cutover areas to functional peat accumulating ecosystems. The approach developed for peatland restoration in North America involves the following steps: 1)field preparation, 2) diaspore collection, 3) diaspore introduction, 4) diaspore protection, and 5) fertilization. Field preparation aims at providing suitable hydrological conditions for diaspores through creation of microtopography and water retention basins, re-shaping cutover fields and blocking ditches. It is site specific because it depends largely onlocal conditions. The second step is the collection of the top 10 centimetres of the living vegetation in a natural bog as a source of diaspores. It is recommended to use a ratio of surface collected to surface restored between 1: 10 and 1: 15 in order to minimize the impact on natural bogs and to insure rapid plant establishment in less than four years. Diaspores are then spread as a thin layer on the bare peat surfaces to be restored. It has been demonstrated that too scant or too thick a layer decreases plant establishment success. Diaspores are then covered by a straw mulch applied at a rate of 3 000 kg ha^-1 which provides improved water availabilityand temperature conditions. Finally, phosphorus fertilization favours more rapid substrate colonization by vascular plants, which have been shown to help stabilize the bare peat surface and act as nurse plants to the Sphagnum mosses.     

Diversity and morphological disparity of desmid assemblages in Central European peatlands

Morphological disparity has increasingly been used as an alternative measure of biological diversity based on the shape features of organisms. In this study, we investigated the species diversity and morphological disparity of benthic Desmidiales in Central European peatland pools. The shape features of cells were determined using the 3-D elliptical Fourier analysis of their frontal and lateral views. The resulting morphospace was used to calculate the contributions of localities and species to the morphological variation. In addition, the disparity of samples and their average cell complexity (indicating intricacy of cell shapes) was evaluated. These data were related to species diversity data and to the abiotic factors. Species diversity was positively correlated with pH and conductivity. The low-pH localities generally supported a more variable species composition than did slightly acidic to neutral localities. Conversely, the total nitrogen concentrations of these areas negatively correlated with species diversity. Interestingly, partial morphological disparity (measuring the contribution of a sample to the overall morphological variation) did not correlate with species diversity. On the contrary, several mountain peat bog localities had high disparity values, irrespective of their rather low species diversity. In addition, several samples from minerotrophic fens with high diversity had average or low values of partial morphological disparity. These results indicate the relative importance of mountain peat bogs for the total morphological diversity of Desmidiales within the region that could not be ascertained solely from species diversity data. The inner morphological disparity of samples was highly correlated with their species diversity. Species of the genus Micrasterias, Hyalotheca dissiliens and Desmidium species had the highest partial morphological disparity, thus indicating their marginal position within the morphospace. Micrasterias and Euastrum species had the highest complexity values. The average cell complexity of individual samples did not correlate with their diversity or disparity; however, it was positively correlated with the levels of total nitrogen and phosphorus, and illustrates a pattern different from that arrived at by species diversity data. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Handling editor: J. Padisak     

Representatives of the genus Ammosiphonia He, 1977 (Foraminifera) from the Jurassic and Carboniferous of Western Siberia

The wide distribution of the genus Ammosiphonia in the Upper Jurassic and Carboniferous of Western Siberia is established for the first time. Six haplophragmoidid species of Western Siberia are assigned to this genus. The diagnosis of the genus is emended; the taxonomic positions and scopes of the species Ammosiphonia nonioninoides (Reuss), A. beresoviensis (Bulatova), and A. sibirica (Zaspelova) are revised; two new species, A. suprajurassica sp. nov. and A. valanginica sp. nov., are described.     

Influence of Ni, Co, Fe, and Na additions on methane production in Sphagnum-dominated Northern American peatlands

Although Sphagnum (moss)-dominated, northern peatlandecosystems harbor methane (CH₄)-producing microorganisms(methanogens) and are a significant source of atmosphericCH₄, rates of CH₄ production vary widely amongdifferent systems. Very little work has been done to examine whetherconcentrations of cations and metal elements may account for thevariability. We examined rates of CH₄ production in peat fromfive geographically and functionally disparateSphagnum-dominated peatlands by incubating peat samples invitro with and without additions of trace metals (Fe, Ni, Co) andbase cations (Ca, Li, Na). In peat from the most mineral poor sites, theaddition of metals and Na enhanced CH₄ production beyond thatobserved in controls. The same treatments in mineral rich sites yieldedno effect or an inhibition of CH₄ production. None of thetreatments affected anaerobic respiration, measured as CO₂production, in the in vitro incubations of peat, except addedcitrate, suggesting that methanogens, and not the entire anaerobiccommunity, can be limited by the availability of metal elements andcations.     

The Saprotrophic Bacterial Complex in the Raised Peat Bogs of Western Siberia

The population density of bacteria in peat deposits along the landscape profile of the Vasyugan Marsh has been found to be as high as tens of millions of CFU/g peat. The abundance and diversity of bacteria increased with depth within the peat deposit, correlating with an increasing level of peat degradation. Variations in these parameters with depth and season were greater in peat deposits located in transaccumulative and transitional positions than in the sedge-sphagnum bogs located at the eluvial region of the profile. In the upper 1-m-thick layer of the peat deposits studied, bacilli, represented by five species, dominated, whereas, in the deeper layers, spirilla and myxobacteria prevailed. These bacteria are major degraders of plant polymers. Unlike the bacterial communities found in the peat deposits of European Russia, the dominant taxa in the studied peat deposits of western Siberia are represented by bacteria resistant to extreme conditions.__________Translated from Mikrobiologiya, Vol. 74, No. 4, 2005, pp. 545–551.Original Russian Text Copyright © 2005 by Golovchenko, Sannikova, Dobrovol’skaya, Zvyagintsev.     

Prokaryotic diversity in one of the largest hypersaline coastal lagoons in the world

Araruama Lagoon is an environment characterized by high salt concentrations. The low raining and high evaporation rates in this region favored the development of many salty ponds around the lagoon. In order to reveal the microbial composition of this system, we performed a 16S rRNA gene survey. Among archaea, most clones were related to uncultured environmental Euryarchaeota. In lagoon water, we found some clones related to Methanomicrobia and Methanothermococcus groups, while in the saline pond water members related to the genus Haloarcula were detected. Bacterial community was dominated by clones related to Gamma-proteobacteria, Actinobacteria, and Synechococcus in lagoon water, while Salinibacter ruber relatives dominated in saline pond. We also detected the presence of Alpha-proteobacteria, Pseudomonas-like bacteria and Verrucomicrobia. Only representatives of the genus Ralstonia were cosmopolitan, being observed in both systems. The detection of a substantial number of clones related to uncultured archaea and bacteria suggest that the hypersaline waters of Araruama harbor a pool of novel prokaryotic phylotypes, distinct from those observed in other similar systems. We also observed clones related to halophilic genera of cyanobacteria that are specific for each habitat studied. Additionally, two bacterioplankton molecular markers with ecological relevance were analyzed, one is linked to nitrogen fixation (nifH) and the other is linked to carbon fixation by bacterial photosynthesis, the protochlorophyllide genes, revealing a specific genetic distribution in this ecosystem. This is the first study of the biogeography and community structure of microbial assemblages in Brazilian tropical hypersaline environments. This work is directed towards a better understanding of the free-living prokaryotic diversity adapted to life in hypersaline waters.     

Effects of hydrologic changes on aboveground production and surface water chemistry in two boreal peatlands in Alberta: Implications for global warming

Aboveground net primary production (NPP) and surface water chemistryvariables were monitored in a lacustrine sedge fen and a bog for four years.There were no significant differences in precipitation, mean growing seasonannual temperature, and number of growing degree days from 1991 to 1994. Themean annual water levels in the lacustrine sedge fen differed significantly,whereas they were similar in the bog during these four years. We measured 15surface water variables in the lacustrine sedge fen and the bog, and foundthat only two correlated significantly with water level fluctuations. In thelacustrine sedge fen, calcium correlated positively (r²= 0.56) and nitrate correlated negatively (r² =0.20) with water levels. In the bog, potassium correlated positively(r² = 0.88) and total dissolved phosphorus correlatednegatively (r² = 0.62) with water levels. The remainingchemical variables showed no significant correlations with water levelfluctuations. Net primary production of the different vegetation strataappeared to respond to different environmental variables. In the lacustrinesedge fen, graminoid production was explained to a significant degree bywater levels (r² = 0.53), whereas shrub production wasexplained to a significant degree by surface water chemistry variables, suchas nitrate (r² = 0.74) and total phosphorus(r² = 0.22). In the bog, temperature was the onlyvariable that explained moss production to a significant degree(r² = 0.71), whereas ammonium explained graminoidproduction (r² = 0.66) and soluble reactive phosphorusexplained shrub production to significant degrees (r² =0.71). There are few direct data on the impact of climatic warming in borealwetlands, although paleoecological and 2×CO₂ model datahave provided some indications of past and possibly future changes invegetation composition, respectively. Our results suggest that thelacustrine sedge fen may succeed to a bog dominated by Sphagnum spp. andPicea mariana, whereas the bog may succeed to an upland-type forestecosystem. This revised version was published online in July 2006 with corrections to the Cover Date.     

Above- and below-ground phytomass and net primary production in boreal mire ecosystems of Western Siberia

We measured phytomass stock and production in Western Siberian mire ecosystems (palsa, ridge, oligotrophic and mesotrophic hollows, fen). To determine the contribution of different phytomass fractions into total production, we developed a method to estimate below-ground production (BNP). Standing crop of living above-ground phytomass on treeless plots varied from 300 to 660 g m⁻², reaching maximum on palsa, where 81% of phytomass consisted of Sphagnum mosses and lichens. In the hollows and the fen, Sphagnum percentage varied from 70 to 95%. Standing crop of living below-ground phytomass varied from 325 to 1,210 g m⁻². It consisted of woody stems, stem bases, rhizomes and roots, with the latter contributing from 30 to 60%. Total production of mire ecosystems in northern taiga of Western Siberia ranged from 350 to 960 g m⁻² year⁻¹ and depended on microtopography of the ecosystem (the presence of permafrost and water table depth). Production of treeless plant communities located on the elevated sites depended on the presence of permafrost: in comparison with the ridge, palsa production was lower. Production on the low sites increased with increase pH and reached maximum (960 g m⁻² year⁻¹) in poor fens. Bryophytes were the major producers above ground. Their production varied from 100 to 272 g m⁻² year⁻¹ and reached maximum on ridges. BNP contributed 37–66%, increasing due to increased contribution of sedges.     

Carbon budget of oligotrophic mire sites in the Southern Taiga of Western Siberia

The results of a long-term (1999–2007) investigation of vegetation productivity and carbon dioxide (CO₂) emission from the surface of an oligotrophic mire in southern taiga in Western Siberia are presented. The studied ecosystems include pine—shrub—sphagnum (PSS) community, a similar community with oppressed (low) tree stand (LPSS), and sedge—sphagnum fen (SSF). Net primary production for PSS, LPSS and SSF are equal to 552, 575, and 561 g m^?2 yr^?1. The mean respiration during the snow-free season determined by chamber method is 165.8, 105.6, 112.4 mgCO₂ m^?2 h^?1 for PSS, LPSS and SSF, respectively. Field measurements of NPP and CO₂ emission in combination with reference data on methane emission, winter CO₂ and CH₄ emissions and carbon export by river run–off were used to develop an overall carbon budget of the mire ecosystems. At present conditions the studied mire ecosystems are net sinks for atmospheric carbon and accumulate peat. Rates of the actual modern carbon accumulation are equal to 21, 112 and 102 g C m^?2 yr^?1 for PSS, LPSS and SSF communities.     

Opisthorchiasis in infant remains from the medieval Zeleniy Yar burial ground of XII-XIII centuries AD

We present a paleoparasitological analysis of the medieval Zeleniy Yar burial groundof the XII-XII centuries AD located in the northern part of Western Siberia. Parasiteeggs, identified as eggs of Opisthorchis felineus, were found in thesamples from the pelvic area of a one year old infant buried at the site. Presence ofthese eggs in the soil samples from the infant’s abdomen suggests that he/she wasinfected with opisthorchiasis and imply consumption of undercooked fish. Ethnographicrecords collected among the population of the northern part of Western Siberia revealnumerous cases of feeding raw fish to their children. Zeleniy Yar case ofopisthorchiasis suggests that this dietary custom has persisted from at leastmedieval times.     

The application of multivariate land classification to vegetation survey in the Wicklow Mountains,Ireland

Multivariate land classification and land cover mapping by aerial photographic interpretation were used to model spatial variation of land cover in the Wicklow Mountains, Ireland and to structure a stratified random sampling programme of upland blanket bog vegetation. The total area of blanket bog with gully-erosion features was estimated as 33% of the area studied. Vegetation with hand peat-cutting patterns was estimated at 5%, and there was 35% undissected (intact) vegetation. There were differences between land classes in the estimated area of land cover with gully-erosion features or hand peat-cutting patterns.Sample vegetation quadrats, stratified by land class and aerial photographic land cover type, were grouped by their plant species composition. The groups represented ombrotrophic mire, soligenous mire and shrub heath vegetation. There was significant association between vegetation group and land class, related to variation in regional landscape type, but no significant association between vegetation group and the aerial photographic land cover types, undissected (intact) and dissected (gullied and cut-over) peats. It is proposed that the similarity of vegetation between undissected and dissected blanket bog is related to vegetation regeneration. The need to consider differences in vegetation distribution, composition and dynamics in ecological management strategies is emphasised. The study demonstrated the value of stratified random field sampling for cost-efficient regional ecological assessment in upland blanket bog landscapes typified by the Wicklow mountains, Ireland.