Laatokan laineilla, Äänisen aalloilla

Kirjallisuusarvostelu

An inter-regional assessment of concentrations and δ13C values of methane and dissolved inorganic carbon in small European lakes

Methane (CH4) and carbon dioxide emissions from lakes are relevant for assessing the greenhouse gas output of wetlands. However, only few standardized datasets describe concentrations of these gases in lakes across different geographical regions. We studied concentrations and stable carbon isotopic composition (δ13C) of CH4 and dissolved inorganic carbon (DIC) in 32 small lakes from Finland, Sweden, Germany, the Netherlands, and Switzerland in late summer. Higher concentrations and δ13C values of DIC were observed in calcareous lakes than in lakes on non-calcareous areas. In stratified lakes, δ13C values of DIC were generally lower in the hypolimnion due to the degradation of organic matter (OM). Unexpectedly, increased δ13C values of DIC were registered above the sediment in several lakes. This may reflect carbonate dissolution in calcareous lakes or methanogenesis in deepwater layers or in the sediments. Surface water CH4 concentrations were generally higher in western and central European lakes than in Fennoscandian lakes, possibly due to higher CH4 production in the littoral sediments and lateral transport, whereas CH4 concentrations in the hypolimnion did not differ significantly between the regions. The δ13C values of CH4 in the sediment suggest that δ13C values of biogenic CH4 are not necessarily linked to δ13C values of sedimentary OM but may be strongly influenced by OM quality and methanogenic pathway. Our study suggests that CH4 and DIC cycling in small lakes differ between geographical regions and that this should be taken into account when regional studies on greenhouse gas emissions are upscaled to inter-regional scales.

The last decade of European history and the great war,

Cover title.

Bohemia under Hapsburg misrule; a study of the ideals and aspirations of the Bohemian and Slovak peoples, as they relate to and are affected by the great European war,

Have the Bohemians a place in the sun? By T. Čapek.--The Slovak of Hungary, by T. Čapek.--Why Bohemia deserves freedom, by B. Šimek.--The Bohemian character, by H. A. Miller.--Place of Bohemia in the creative arts, by W. S. Monroe.--The Bohemians and the Slavic regeneration, by L. Wiener.--The Bohemians as immigrants, by Emil G. Balch.

History of the discovery and settlement of the valley of the Mississippi, by the three great European powers, Spain, France, and Great Britain, and the subsequent occupation, settlement, and extension of civil government by the United States until the year 1846 /

References: Howes, U.S.IANA, no. M.722.

Non-indigenous species in the North and Baltic Seas and the Great Lakes-St. Lawrence River region

List of non-indigenous species (NIS) established in the Great Lakes-St. Lawrence River region and the North and Baltic Seas region, their geographic origin, and taxonomic assignment. Asterisks mark the NIS that occur in both the North and Baltic Seas and the Great Lakes-St. Lawrence River regions. GL, SL, NW, NE, SW and SE denote the Great Lakes, St. Lawrence River, north-west, north-east, south-west, and south-east, respectively. Eurasia represents inland freshwaters except Yangtze River, Indo-Pacific represents Indian Ocean and the archipelago of Indonesia, Malaysia, and Pilipinas, North America (N America) represents inland freshwaters except the Laurentian Great Lakes, St. Lawrence and Mississippi Rivers, while Australia, New Zealand, Africa and South America (S America) cover all inland freshwaters in these areas.

Postglacial paleoecology and effects of European settlement on the environment of Lake Hunger and Lake Lisgar, Southwestern Ontario /

This investigation has three purposes I to make a comparative chemical study on sediment cores collected for Lake Lisgar (man-made lake in an urban center) and Lake Hunger (natural basin in a rural community) encompassing the time since European settlement I to determine the postglacial chemical history of Lake Hunger, and to determine the vegetational history of the Lake Hunger area from postglacial time to the present. The minus 80 mesh fraction of 108 soil samples and 18 stream sediment samples collected in the vicinity of Lakes' Lisgar and Hunger were analyzed for cold hydrochloric acid soluble lead, zinc, nickel, cobalt, copper, aluminum, sodium, potassium, calcium, magnesium, iron and manganese. Lacustrine sediments from 5 boreholes in the Lake Lisgar basin were collected. Boreholes 1, 2, 3, and 4 were analyzed for palynological and chemical information and Borehole 5 was subjected to pollen and ostracode analysis. Lacustrine sediments from 6 boreholes in the Lake Hunger basin were collected. Palyno- -logical and chemical analysis were performed on Boreholes 1, 2, 3, 4, and 6 and Borehole 5 was analyzed for pollen. In addition, radiocarbon dates were obtained on sediment samples from Boreholes 4 and 5. A total of 8 surface samples were collected from the margins of the Lake Hunger basin and these were chemically analyzed in the laboratory. All of the lacustrine sediments were ashed and analyzed for cold hydrochloric acid soluble lead, zinc, nickel, cobalt, copper, aluminum, sodium, potassium, calcium, magnesium, iron and manganese using a Perkin Elmer 40) Atomic Absorption spectrophotometer. The results . obtained for the 12 elements were expressed as parts per million in dry sediments. It was found that man's influence on the element distribution patterns in the sediments of Lake Lisgar appeared to be related to his urbanizing developments within the lake vicinity, whereas, the rural developments in the vicinity of lake Hunger appeared to have had little effect on the element distribution patterns in the lake sediments. The distribution patterns of lead, zinc, nickel, cobalt, aluminum, magnesium, sodium and potassium are similar to the % ash curve throughout postglacial time indicating that the rate of erosion in the drainage basin is the main factor which controls the concentration of these elements in the sediments of Lake Hunger. The vegetational history, from palynological analysis, of Lake Hunger from postglacial time to the present includes the following stages: tundra, open spruce forest, closed boreal forest, deciduous forest and the trend towards the re-establishment of pine following the clearing of land and the subsequent settlement of the Lake Hunger area by European settlers. The concentrations of some elements (cobalt, nickel, iron, manganese, calcium, magnesium, sodium and potassium) in the sediments of Lake Hunger appears to be higher during pre-cultural compared to post-cultural times. At least one complete postglacial record of the chemical history within a lake basin is necessary in order to accurately assess man's effects on his environment.

Researching and designing GREAT; the extremely condensed hybrid urban block

The fact that the hybrid building is an extremely condensed urban block which increases the city’s density and contributes to the public realm of the city – horizontally as well vertically - forms one of the key interests of this documentation, research and master studio work. The “ground scraper” is not only public because of the character of its plinth facing surrounding streets, but also in regard to its interior space that is partly accessible to public. As such the European hybrid building potentially extends the city’s public domain horizontally and vertically into the building’s interior and links the public domain inside and outside. Notwithstanding, the hybrid building due to its specific and unconventional character represents a truly urban architecture that was unfortunately often rejected in the name of ‘purity’ of form and function during the twentieth century. Or with other words, its rejection demonstrates the domination of the building’s plan opposed to the section. Today, new frameworks for the city, like the “compact city,” ask for innovative interpretations and designs of building types, worthy to be investigated and proposed. The architectural type of the hybrid building, (re)defines and expresses the relation between architecture and the city in a specific manner. To begin with, the city of Rotterdam forms the first test-case of the Hybrid’s project to document and discuss statements, such as “the hybrid building has a long- standing tradition within this ‘modern city”, “it is a machine for urbanity,” “it enlarges the city,” “it innovates because of its ambitiousness but also because of necessity,” “it combines to activate,” “it asks for extraordinary design intelligence and craftsmanship.” A special way of drawing is developed to document, analyse and compare historical and contemporary representatives of the species. The method includes panoply of scales ranging from the morphological arrangement on the scale of the city, the typologies of stacking diverse programs to the architectural features that establish the mutual relationship between the public space of the city and the interior of the building. Basically the features analysed within the series of drawings are also constitutional for (the success of) every future hybrid building.

Lake ice phenology from AVHRR data for European lakes: An automated two-step extraction method

Several lake ice phenology studies from satellite data have been undertaken. However, the availability of long-term lake freeze-thaw-cycles, required to understand this proxy for climate variability and change, is scarce for European lakes. Long time series from space observations are limited to few satellite sensors. Data of the Advanced Very High Resolution Radiometer (AVHRR) are used in account of their unique potential as they offer each day global coverage from the early 1980s expectedly until 2022. An automatic two-step extraction was developed, which makes use of near-infrared reflectance values and thermal infrared derived lake surface water temperatures to extract lake ice phenology dates. In contrast to other studies utilizing thermal infrared, the thresholds are derived from the data itself, making it unnecessary to define arbitrary or lake specific thresholds. Two lakes in the Baltic region and a steppe lake on the Austrian–Hungarian border were selected. The later one was used to test the applicability of the approach to another climatic region for the time period 1990 to 2012. A comparison of the extracted event dates with in situ data provided good agreements of about 10 d mean absolute error. The two-step extraction was found to be applicable for European lakes in different climate regions and could fill existing data gaps in future applications. The extension of the time series to the full AVHRR record length (early 1980 until today) with adequate length for trend estimations would be of interest to assess climate variability and change. Furthermore, the two-step extraction itself is not sensor-specific and could be applied to other sensors with equivalent near- and thermal infrared spectral bands.

Abundance and sizes of European oak species (Quercus petraea (Matt.) Liebl., Quercus robur L.) in dependence of neighborhood and environmental factors

Quercus robur L. (pedunculate oak) and Quercus petraea (Matt.) Liebl. (sessile oak) are two European oak species of great economic and ecological importance. Even though both oaks have wide ecological amplitudes of suitable growing conditions, forests dominated by oaks often fail to regenerate naturally. The regeneration performance of both oak species is assumed to be subject to a variety of variables that interact with one another in complex ways. The novel approach of this research was to study the effect of many ecological variables on the regeneration performance of both oak species together and identify key variables and interactions for different development stages of the oak regeneration on a large scale in the field. For this purpose, overstory and regeneration inventories were conducted in oak dominated forests throughout southern Germany and paired with data on browsing, soil, and light availability. The study was able to verify the assumption that the occurrence of oak regeneration depends on a set of variables and their interactions. Specifically, combinations of site and stand specific variables such as light availability, soil pH and iron content on the one hand, and basal area and species composition of the overstory on the other hand. Also browsing pressure was related to oak abundance. The results also show that the importance of variables and their combinations differs among the development stages of the regeneration. Light availability becomes more important during later development stages, whereas the number of oaks in the overstory is important during early development stages. We conclude that successful natural oak regeneration is more likely to be achieved on sites with lower fertility and requires constantly controlling overstory density. Initially sufficient mature oaks in the overstory should be ensured. In later stages, overstory density should be reduced continuously to meet the increasing light demand of oak seedlings and saplings.

Measurements of gastropods shell sizes from 23 fossil and extant long-lived lakes

Aim: To investigate shell size variation among gastropod faunas of fossil and recent long-lived European lakes and discuss potential underlying processes. Location: 23 long-lived lakes of the Miocene to Recent of Europe. Methods: Based on a dataset of 1412 species of both fossil and extant lacustrine gastropods, we assessed differences in shell size in terms of characteristics of the faunas (species richness, degree of endemism, differences in family composition) and the lakes (surface area, latitude and longitude of lake centroid, distance to closest neighbouring lake) using multiple and linear regression models. Because of a strong species-area relationship, we used resampling to determine whether any observed correlation is driven by that relationship. Results: The regression models indicated size range expansion rather than unidirectional increase or decrease as the dominant pattern of size evolution. The multiple regression models for size range and maximum and minimum size were statistically significant, while the model with mean size was not. Individual contributions and linear regressions indicated species richness and lake surface area as best predictors for size changes. Resampling analysis revealed no significant effects of species richness on the observed patterns. The correlations are comparable across families of different size classes, suggesting a general pattern. Main conclusions: Among the chosen variables, species richness and lake surface area are the most robust predictors of shell size in long-lived lake gastropods. Although the most outstanding and attractive examples for size evolution in lacustrine gastropods derive from lakes with extensive durations, shell size appears to be independent of the duration of the lake as well as longevity of a species. The analogue of long-lived lakes as 'evolutionary islands' does not hold for developments of shell size because different sets of parameters predict size changes.

Between the lines on the American front: a boys' story of the great European war,

Mode of access: Internet.