Palatine torus in the Greenlandic Norse.

Physical anthropologists have long been intrigued by the distinctive oral tori expressed by the medieval Norse populations of Iceland and Greenland. To assess the temporal and spatial variation of one form of oral tori, palatine torus, observations were made on all available Greenlandic Norse skeletons, as well as on samples of medieval Icelanders and Norwegians. In terms of temporal variation, 12th to 14th century (medieval) Greenlanders from the Eastern and Western settlements exhibited higher frequencies and more pronounced expressions of palatine torus compared with early 11th century Greenlanders. The early Greenlandic sample closely approximated the medieval Icelandic and Norwegian samples for total torus frequency, although the Norwegians exhibited the trait to a less pronounced degree. As degree of expression is the most distinctive aspect of torus variation among the Norse, some combination of environmental factors, including increased masticatory stress and chronic undernutrition, probably accounts for most of the difference between settlement period and medieval Greenlanders. Although palatine torus may be hereditary in part, environmental factors play a significant role in the expression of this trait.     

Winter North Atlantic oscillation effects on the tree rings of the Italian beech (Fagus sylvatica L.)

Climatic signals in beech tree-ring width series from Central Italy have been studied over different periods of time. Prewhitened tree-ring chronologies respond mainly to summer precipitation and they do not correlate in a significant manner with the winter North Atlantic oscillation (NAO) index. In this high-frequency pattern the NAO signs are only found on a small number of rings characterized by being very narrow or wide. By contrast, tree-ring width chronologies in which all the frequency components are conserved were significantly related to the NAO. The significant inverse correlation between actual measurements of ring width and NAO is a consequence of the availability of water in the soil at the beginning of the growing season. In fact, in the Mediterranean area the recharging of soil moisture depends on the amount of winter precipitation, which is inversely correlated with the NAO. Strong signals of winter precipitation and NAO are found in the low-frequency components of tree-ring growth. Received: 18 March 1999 / Revised: 29 February 2000 / Accepted: 1 March 2000     

Alnus Pollen Incidence in the Stockholm Area, 1973-1976

Alder (Alnus) pollen in Stockholm, central Sweden, was sampled by means of a Burkard Volumetric Spore Trap and analysed during four consecutive years, 1973 to 1976. The start of the season and the main pollen season occurred in March during the first three years and much later in 1976. The difference between any two years seems to be related to differences in temperature, pollen incidence being initiated by a steady increase. A mild decade followed by a marked temperature increase seems to favour the initiation of the main pollen season. More than 50% of the total pollen amount was found between 10 a.m. and 6 p.m. Differences in the amounts of pollen over the years could not be explained by contemporary climatic changes.     

Large-scale climatic phenomena and timing of breeding in a local population of the Osprey Pandion haliaetus in southern Finland

The effects of large-scale climatic phenomena on the timing of breeding in the Osprey Pandion haliaetus were studied during 1981–2006 in a small local population of about 20 pairs near the southern coast of Finland. The timing of breeding was estimated on the basis of the wing length of the largest young within the brood. The wing lengths were plotted against the date of the measurement to get a linear regression model characterizing the average developmental stage of broods in relation to date. This model was used when converting the measurements to correspond to the median date of all the measurements. Large-scale climatic phenomena were characterized by the winter and monthly indices of the North Atlantic oscillation (NAO). A significant positive relationship between the winter NAO index and timing of breeding in the Osprey, as indicated by the wing length of the largest young in the brood, was found. The relationship was even stronger when only the monthly value of January was considered. These relationships seemed to be linked with consequent earlier ice melting after mild winters. The results indicate prominent effects of large-scale climatic phenomena and that they can be monitored with relatively modest effort.     

Bioluminescent monitoring of turbulent bioconvection.

Under adjusted experimental conditions, open-to-air cultures of lux gene-engineered Ralstonia eutropha (wholecell biosensors of copper) exhibit bioconvection, which accounts for fluctuating bioluminescence. The power spectrum of bioluminescence intensity fluctuations recorded from a cylindrical sample 9 mm in diameter and approximately 10 mm in height is characterized by a dominant low-frequency oscillation (with a characteristic period of approximately 8-12 min), which is occasionally accompanied by a few weaker oscillations. The corresponding spectral peaks emerge on a high-noise background. The spectra of bioluminescence intensity fluctuations qualitatively resemble the spectra of temperature or fluid velocity fluctuations in an appropriate turbulent thermal convection system. It has been suggested that in a bioconvective system, like in thermal convection systems, the emergence of oscillation reflects the large-scale convective circulation that spans the height of the cylindrical cell. The velocity of large-scale bioconvective circulation was estimated to be 37-48 microm/s. The occasional emergence of weaker-than-dominant oscillations was explained through the coexistence and interaction of the large-scale circulation with, presumably, a gene-expression-related cyclic process (with a characteristic period of approximately 25-50 min).     

西藏扎布耶盐湖地区现代花粉雨的初步研究

从扎布耶盐湖和藏南地区采集的２１块表土花粉分析结果,提供了花粉与植被,花粉与亚环境之间的定性关系,在扎耶盐湖,ａ泉水沼泽,以莎草科花粉占优势。ｂ．盐盘,藜科和麻黄属花粉含量高。ｃ．山坡,分布变色锦鸡儿灌丛,表土花粉以蒿属和藜科为优势。ｄ．河流沙滩,以蒿属和禾本科花粉为主,ｅ．常年盐湖,以蒿属占优势,松属、云杉属、冷杉属、铁杉属、桦属和桤木属等乔木植物花表土中普遍存在。以松粉百分含量最高（平均２６．     

Species richness and endemism in the Western Australian flora

Aim Estimates of endemic and non‐endemic native vascular plant species in each of the three Western Australian Botanical Provinces were made by East in 1912 and Beard in 1969. The present paper contains an updated assessment of species endemism in the State. Location Western Australia comprises one third of the continental Australian land mass. It extends from 13° to 35° S and 113° to 129° W. Methods Western Australia is recognized as having three Botanical Provinces (Northern, Eremaean and South‐West) each divided into a number of Botanical Districts. Updated statistics for number of species and species endemism in each Province are based on the Census of Western Australian Plants data base at the Western Australian Herbarium ( Western Australian Herbarium, 1998 onwards). Results The number of known species in Western Australia has risen steadily over the years but reputed endemism has declined in the Northern and Eremaean Provinces where cross‐continental floras are common. Only the isolated South‐West Province retains high rates of endemism (79%). Main conclusions With 5710 native species, the South‐West Province contains about the same number as the California Floristic Province which has a similar area. The Italian mediterranean zone also contains about this number but in a smaller area, while the much smaller Cape Floristic Region has almost twice as many native species. The percentage of endemic species is highest at the Cape, somewhat less in south‐western Australia and less again in California. Italy, at 12.5%, has the lowest value. Apart from Italy, it is usual for endemism to reach high values in the largest plant families. In Western Australia, these mainly include woody sclerophyll shrubs and herbaceous perennials with special adaptations to environmental conditions. While those life forms are prominent in the Cape, that region differs in the great importance of herbaceous families and succulents, both of which are virtually absent from Western Australia. In California and Italy, most endemics are in families of annual, herbaceous perennial and soft shrub plants. It is suggested that the dominant factor shaping the South‐West Province flora is the extreme poverty of the area’s soils, a feature that emphasizes sclerophylly, favours habitat specialization and ensures relatively many local endemic species.     

Temporal changes and fluxes of sulphur and calcium in wet and dry deposition, internal circulation as well as in run-off and soil in a forest at Gårdsjön, Sweden

Sulphur dioxide in air as well as dry deposition of sulphur dioxide to a forest has decreased by a factor of 20 during the last two decades. It was earlier found that the internal circulation of calcium in Norway spruce follows the dry deposition of sulphur dioxide. The sulphur and calcium fluxes from 1992 were calculated from wet deposition, throughfall and a surrogate surface. Earlier fluxes from 1981 to 1991 were calculated using assumptions of the dry deposition of non-marine sulphate and calcium. The new estimates confirm the earlier studies that the internal circulation of calcium in a coniferous forest is directly related to the dry deposition of sulphur dioxide to the canopies and that the internal circulation of calcium decreases at the same rate as the deposition of sulphur decreased during the last two decades. The deposition fluxes were also compared to run-off and uptake of calcium in the forest as well as on modelled weathering rates from severely acidified forested catchments near the coast and inland and the soil pool. A reconstruction of changes in the soil pool of calcium over the last 100 years indicate that the soil pool has decreased by ca. 70% in catchments with complete harvest of the forest and ca. 40% if branches and needles are left on the ground. In a natural forest without acid deposition the soil pool of calcium would have increased by 6%. Estimates for the 21st century show that harvesting of stems+branches and needles may almost empty the soil pool of calcium in the next 100 years. Increased nitrogen deposition has increased forest growth, which indirectly increased uptake of calcium by the trees and indirectly caused a further decrease of the soil pool of calcium.     

Reconstruction of pollutant lead invasion into the tropical North Atlantic during the twentieth century

In this study we reconstruct pollutant lead transport and input into the Caribbean basin in relation to the meteorological changes and past industrial activities. These reconstructions are based on the geochemical data obtained from massive corals collected in 1998 in Mona Island. Lead concentration profile mimics the general atmospheric lead trend obtained from the previous investigations on ice cores, carbonate skeletons and in sediments from the North Atlantic. This similarity corroborates the significance of anthropogenic impact on all reservoirs of the North Atlantic as associated with the proliferation of the automobile and use of leaded gasoline during the twentieth century. Our high-resolution record reveals a 2–4 years shift between the maximum pollutant lead input to Mona Island and leaded gasoline consumption peaks in North America, suggesting a possible longer secondary oceanic transport of US lead within the Subtropical North Atlantic Gyre system. A striking relationship is found between lead isotopic imprints and the winter North Atlantic oscillation (NAO) index for two specific periods (1914–1929 and 1965–1997). These periods are characterized by distinct isotopic signatures from the main pollutant lead emitter to the North Atlantic troposphere, North America and Western Europe. This involves a noteworthy influence of the NAO on pollutant input and distribution in the North Atlantic that strengthens the usefulness of lead isotopes as tracers of paleo-atmospheric circulation and changes in marine circulation pathways.     

Distribution of dimethylsulfide and dimethylsulfoniopropionate and its relation with phytoneuston in the surface microlayer of the western North Atlantic during summer

One of the key steps towards predicting dimethylsulfide (DMS) emission to the atmosphere is to understand the distribution and cycling of biogenic sulfur in the microlayer. In this study, we examined the distribution of DMS and dissolved and particulate fractions of dimethylsulfoniopropionate (DMSPd and DMSPp) in the surface microlayer and bulk water of the western North Atlantic during July 2003. DMS concentrations in the bulk water varied from 0.71 to 7.65 nM. In contrast, DMS concentrations in the surface microlayer were fairly low (0.17–1.33 nM). Average concentrations of DMSPd and DMSPp in the bulk water were 2.09 (1.87–6.25) and 44.1 (8.06–119.8) nM, respectively, and those in the surface microlayer were 15.4 (4.06–54.3) and 29.9 (7.32–97.0) nM. In general, DMS was depleted in the microlayer (mean concentration: 0.60 nM) relative to the bulk water (mean concentration: 2.38 nM) with enrichment factors (the ratio of the microlayer concentration to bulk water concentration) ranging from 0.13 to 0.54. There was no consistent enrichment of DMSPp and chlorophyll a in the microlayer. On the contrary, DMSPd appeared to be highly enriched in the microlayer with an average EF of 4.89. The concentration of phaeopigments was also generally greater in the microlayer than in the bulk water, presumably due to enhanced photo-oxidation of chlorophyll a under high surface light intensities in the microlayer. In the study area, the concentration of DMSPp was significantly correlated with the abundance of dinoflagellates in the microlayer. Moreover, a significant correlation between the distributions of DMS, DMSPp, chlorophyll a and phaeopigment concentrations in the microlayer and the bulk water demonstrated that the biogenic materials in the microlayer come primarily from the bulk water below.     

Why are fruit traits of Cistus ladanifer (Cistaceae) so variable: A multi-level study across the western Mediterranean region

Variation is the raw material for evolution. Differences among populations in the expression of traits related to plant fitness may result from natural selection, phenotypic plasticity (in response to local conditions), and developmental instability (manifested as high intra-individual variation in repeated patterns or characters). Cistus ladanifer is a highly polymorphic plant distributed in the Mediterranean and the only species in the family (Cistaceae, 180 species) with a variable number of valves per fruit. We herein analysed the variation in the number of valves (5–12) and seeds (318–1185) per fruit in 36 populations (607 individuals, 1821 fruits) at different levels: temporal, geographical, ecogeographical, taxonomic, and phylogeographical. In addition, we tested whether an increased number of fruit valves influences pre-dispersal seed predation. Large variation in the number of valves and seeds per fruit among populations, individuals, and years was reported. The number of ovules and seeds per valve increased with a higher number of fruit valves. Geographical and taxonomic variables did not significantly explained this fruit variation. On the contrary, we found a negative relationship between the number of fruit valves and altitude and a positive relationship with precipitation. We argue that ecogeographical factors, in addition to some phylogeographical and phylogenetic signals, are involved in the multiplication of carpels during the development of the ovary wall. This, coupled with the results of the evolutionary history of Cistus in previous studies, indicates active evolutionary processes in C. ladanifer populations.     

Broad-scale patterns of abundance of non-indigenous soft-bottom invertebrates in Denmark

Quantifying the broad-scale distribution and abundance of non-indigenous species (NIS) is necessary to provide accurate estimations on impacts of invasions, to prioritize research, and to guide national management. Sediment grab-sampling is a standardized method for monitoring marine benthos. In Denmark, ~45,000 grab-samples were collected from 1970 to 2005. Using these samples, we compared densities of NIS and native species among 27 broad spatio-temporal groupings. Eight known NIS and one ‘cryptogenic species’ (the polychaete Neanthes succinea) were found in the samples. Most were present in low abundance, but the bivalve Mya arenaria, likely introduced by the vikings from North America, was particularly abundant. M. arenaria was found in ca. 20% of all samples and was among the 10 most common species in all of Denmark. M. arenaria’s high abundance, high filtration capacity and importance in food-web interactions, suggest that this species has dramatically impacted shallow coastal ecosystems in Denmark. The polychaete Marenzelleria viridis, the gastropod Potamopyrgus antipodarum and N. succinea were also widespread and abundant, and they too are likely to have had broad-scale impacts. In conclusion, 28% of grab-samples collected in Denmark over 35 years were affected by some degree of NIS or cryptogenic species, suggesting that centuries of human-mediated transfer of organisms has had a profound impact on the ecology of soft-bottom systems in Denmark.     

Connections between climatic variables and the growth and needle dynamics of Scots pine (Pinus sylvestris L.) in Estonia and Lapland

The relationships between climatic variables and Scots pine (Pinus sylvestris L.) growth and needle dynamics were studied in three stands in Estonia and in four stands located near the northern timberline in Lapland. The trees sampled in Estonia had low correlations with the analysed climatic variables (air temperature, precipitation and indices of atmospheric circulation). Moreover, the weak cross-correlation of the time-series of the Estonian sample trees indicated that Scots pine is affected mainly by local factors in that region. In Lapland, however, height increment and needle production correlated strongly among trees within a stand (mean r=0.45 and 0.46, respectively) and between stands (r=0.32 and 0.37). Radial increment also showed a high inter-correlation among the trees within a stand in Lapland (r=0.45). Both height increment and needle production were strongly influenced by the temperature regime of the previous summer in Lapland (mean r=0.64 and 0.64, respectively). Radial increment was correlated with the mean July temperature of the current year (mean r=0.29). The correlations between the indices of atmospheric circulation and tree attributes were weak, while the strongest correlation was between the Ponta Delgada NAO index (PD–NAO) and height increment and needle production in Lapland. Height increment, needle production and radial increment have increased since the 1990s in the trees growing in Lapland. This may indicate a positive effect of climate warming on tree growth in Lapland. In Estonia, where climatic conditions do not limit tree growth, the climate warming seems not to directly influence the growth and needle dynamics of Scots pine.     

Biotic regionalization and climatic controls in western North America

New methods of weather analysis accompanied by microhabitat ‘bioassays’ have been applied in several case studies to demonstrate effects of atmospheric processes on patterns of community composition and structure and potential species evolution. Average spatial and seasonal airmass dynamics which determine regional and elevational patterns of relative microhabitat favorability, were found to vary between a recent global warming trend (ca 1900 to 1940) and the subsequent global cooling trend (ca 1940 to 1970). These apparently systematic spatial and temporal shifts in weather were related to plant establishment patterns and community composition and structure. The proposed causal mechanisms function, in part, through regional shifts in microhabitat size. These effects are similar to larger scale, longer term shifts deduced from the late Quaternary fossil record. By modifying the spatial approach, month-to-month and year-to-year variability of weather has been examined for the last 130 years at individual points in southwestern North America. Three climatic regimes (the end of the Little Ice Age, the recent warming trend and the recent cooling trend) exhibited distinct year-to-year patterns of weather that can be related to the establishment of different kinds of plants (e.g., C₄ grasses versus C₃ shrubs). Oscillations between different temporal climatic regimes appear to promote the episodic establishment of different life forms, but not necessarily their local extinction. The two methods of weather analysis have been combined in a regional assessment of climatic controls of different biomes in space and time with a primary focus on the Chihuahuan desert. Natural ecotones between the Chihuahuan desert and neighboring biomes are clearly related to large scale airmass dynamics associated with seasonal oscillations in jetstream position. The weather patterns controlling ecotonal positions result from seasonal topographic influences on the general circulation of the atmosphere. The apparent stability of these patterns allows causal hypotheses of biogeographic dynamics and the evolution of physiological traits and life history characteristics.     

Predicting aquatic vertebrate assemblages from environmental variables at three multistate geographic extents of the western USA

Variables for predicting assemblage differences change as the geographic extent of studies change, hindering development of useful predictive models where study data are limited, or where the chief predictive variables available are fish zones, river size, physiographic regions, ecoregions, hydrologic units, and river basins. In addition, some studies have shown that site-scale predictor metrics have accounted for more of the variation in fish assemblage response metrics than catchment-scale metrics and other studies have shown the reverse. We used cluster analysis on a 780-site database to determine 12–15 aquatic vertebrate clusters at three geographic extents (all 12 conterminous western U.S. states, all western mountain ecoregions, Pacific Northwest mountain ecoregions). Next, we determined predictor variables for those assemblage clusters through use of stepwise discriminant function analysis. Site longitude, site latitude, and catchment dam count were the most significant predictors at the three geographic extents. Site-scale variables represented most of the significant predictors for all three geographic extents, but explained only slightly more aquatic vertebrate assemblage variance than catchment or pure spatial variables. Catchment- and site-scale classification variables accounted for less than half the mean within-cluster similarity demonstrated by the aquatic vertebrate assemblage clusters. We conclude that (a) the large geographic extent of the analysis did not result in catchment-scale predictor variables being more important than site-scale predictors, (b) both catchment- and site-scale variables are important predictors, and (c) existing river basin and ecoregion classifications are useful but insufficient predictors of aquatic vertebrate assemblages.