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11	Paleoenvironmentální rekonstrukce mladšího dryasu na základě subfosilních perlooček / Palaeoenvironmental reconstruction of the Younger Dryas based on subfubfossil cladocera Bubenková, Anna January 2020 (has links) 5 ABSTRACT Long-term paleoenvironmental reconstructions provides essential interpretation of environmental changes. Multiproxy analysis of lake sediments can be used for tracking the historical evolution of lakes and significant processes which formed them over time. Subfossil Cladocera play a key ecological role in freshwater ecosystems. Sedimentary cladoceran assemblages reflect environmental changes and exhibit great potential in past environmental reconstructions. The purpose of this diploma thesis is to identify climatic changes of the time interval between the Late Glacial and the early Holocene in Černé Lake. Based on the analysis of geochemical and biological proxies, determined climatic conditions of Younger Dryas (YD). The YD oscillation in Central Europe has only been briefly described. The Czech Republic is positioned between oceanic and continental climate. The results of the multiproxy analyses suggests that climate conditions of the region during YD were similar to Western Europe with moderate wet climate conditions during the first half and drier conditions during the second half of the period. In the middle of YD there was an interesting event. Observed, probably due to high precipitation and floods. These results are based on P/L ratio, geochemical proxies, pollen analyses and record of...
12	Kvartérní paleoekologická analýza NPR Soos / The Quaternary Paleoecological Analysis of the Soos National Nature Reserve Rajdlová, Hana January 2011 (has links) The Quaternary Paleoecological Analysis of the Soos National Nature Reserve The aim of this proposed diploma thesis is to describe the structure of diatom communities in the diatomite deposits of the Soos National Nature Reserve and compare the finding of this thesis with those of older publications. Another aim was to reconstruct the history of the basin trough with the outputs of diatom analysis accomplished in the 3,4 m long sediment profile. The similarity of diatom communites in individual diatomite types was also tested. Key words: subfossil diatoms, Soos National Nature Reserve, paleolimnology, Late Glacial, Holocene
13	Tree Rings as Sensitive Proxies of Past Climate Change Grudd, Håkan January 2006 (has links) <p>In the boreal forests of the Northern Hemisphere, time series of tree-ring width (TRW) and maximum density in the latewood (MXD) are highly correlated to local instrumental summer-temperature data and are thus widely used as proxies in high-resolution climate reconstructions. Hence, much of our present knowledge about climatic variability in the last millennium is based on tree-rings. However, many tree-ring records have a lack of data in the most recent decades, which severely hampers our ability to place the recent temperature increase in a longer-timescale perspective of natural variability.</p><p>The main objective of this thesis is to update and extend the Torneträsk TRW and MXD records in northern Sweden. Local instrumental climate-data is used to calibrate the new tree-ring records. The results show that TRW is mainly forced by temperature in the early growing season (June/July) while MXD has a wider response window (June – August) and has a higher correlation to temperature. Two reconstructions of summer temperature are made for (i) the last 7,400 years based on TRW, and (ii) the last 1,500 years based on a combination of TRW and MXD. The reconstructions show natural variability on timescales from years to several centuries. The 20th century does not stand out as a notably warm period in the long timescale perspective. A medieval period from AD 900 – 1100 is markedly warmer than the 20th century.</p><p>The environmental impact from a large explosive volcanic eruption in 1628/1627 BC is analysed in the tree rings of 14C-dated bog pines in south-central Sweden and in absolutely-dated subfossil pines from Torneträsk. The results show evidence of an impact in the southern site at approximately this time but no detectable impact in the North. </p><p>Subfossil trees of Fitzroya cupressoides in southern Chile were 14C-dated to approx. 50,000 years BP and amalgamated into a 1,229-year TRW chronology. This tree-ring record is the oldest in the world. The variability in this Last-glacial chronology is similar to the variability in present-day living trees of the same species. These results suggest that the growth–forcing mechanisms 50,000 years ago were similar to those at present.</p> Tree ring width density climate temperature change variability sensitivity Torneträsk Tornetrask Sweden Fennoscandia explosive volcanic eruption Santorini Thera subfossil Fitzroya Chile Physical geography Naturgeografi
14	Tree Rings as Sensitive Proxies of Past Climate Change Grudd, Håkan January 2006 (has links) In the boreal forests of the Northern Hemisphere, time series of tree-ring width (TRW) and maximum density in the latewood (MXD) are highly correlated to local instrumental summer-temperature data and are thus widely used as proxies in high-resolution climate reconstructions. Hence, much of our present knowledge about climatic variability in the last millennium is based on tree-rings. However, many tree-ring records have a lack of data in the most recent decades, which severely hampers our ability to place the recent temperature increase in a longer-timescale perspective of natural variability. The main objective of this thesis is to update and extend the Torneträsk TRW and MXD records in northern Sweden. Local instrumental climate-data is used to calibrate the new tree-ring records. The results show that TRW is mainly forced by temperature in the early growing season (June/July) while MXD has a wider response window (June – August) and has a higher correlation to temperature. Two reconstructions of summer temperature are made for (i) the last 7,400 years based on TRW, and (ii) the last 1,500 years based on a combination of TRW and MXD. The reconstructions show natural variability on timescales from years to several centuries. The 20th century does not stand out as a notably warm period in the long timescale perspective. A medieval period from AD 900 – 1100 is markedly warmer than the 20th century. The environmental impact from a large explosive volcanic eruption in 1628/1627 BC is analysed in the tree rings of 14C-dated bog pines in south-central Sweden and in absolutely-dated subfossil pines from Torneträsk. The results show evidence of an impact in the southern site at approximately this time but no detectable impact in the North. Subfossil trees of Fitzroya cupressoides in southern Chile were 14C-dated to approx. 50,000 years BP and amalgamated into a 1,229-year TRW chronology. This tree-ring record is the oldest in the world. The variability in this Last-glacial chronology is similar to the variability in present-day living trees of the same species. These results suggest that the growth–forcing mechanisms 50,000 years ago were similar to those at present. Tree ring width density climate temperature change variability sensitivity Torneträsk Tornetrask Sweden Fennoscandia explosive volcanic eruption Santorini Thera subfossil Fitzroya Chile Physical Geography Fysisk geografi
15	Tree Rings as Sensitive Proxies of Past Climate Change Grudd, Håkan January 2006 (has links) In the boreal forests of the Northern Hemisphere, time series of tree-ring width (TRW) and maximum density in the latewood (MXD) are highly correlated to local instrumental summer-temperature data and are thus widely used as proxies in high-resolution climate reconstructions. Hence, much of our present knowledge about climatic variability in the last millennium is based on tree-rings. However, many tree-ring records have a lack of data in the most recent decades, which severely hampers our ability to place the recent temperature increase in a longer-timescale perspective of natural variability. The main objective of this thesis is to update and extend the Torneträsk TRW and MXD records in northern Sweden. Local instrumental climate-data is used to calibrate the new tree-ring records. The results show that TRW is mainly forced by temperature in the early growing season (June/July) while MXD has a wider response window (June – August) and has a higher correlation to temperature. Two reconstructions of summer temperature are made for (i) the last 7,400 years based on TRW, and (ii) the last 1,500 years based on a combination of TRW and MXD. The reconstructions show natural variability on timescales from years to several centuries. The 20th century does not stand out as a notably warm period in the long timescale perspective. A medieval period from AD 900 – 1100 is markedly warmer than the 20th century. The environmental impact from a large explosive volcanic eruption in 1628/1627 BC is analysed in the tree rings of 14C-dated bog pines in south-central Sweden and in absolutely-dated subfossil pines from Torneträsk. The results show evidence of an impact in the southern site at approximately this time but no detectable impact in the North. Subfossil trees of Fitzroya cupressoides in southern Chile were 14C-dated to approx. 50,000 years BP and amalgamated into a 1,229-year TRW chronology. This tree-ring record is the oldest in the world. The variability in this Last-glacial chronology is similar to the variability in present-day living trees of the same species. These results suggest that the growth–forcing mechanisms 50,000 years ago were similar to those at present. Tree ring width density climate temperature change variability sensitivity Torneträsk Tornetrask Sweden Fennoscandia explosive volcanic eruption Santorini Thera subfossil Fitzroya Chile Physical geography Naturgeografi
16	Historický vývoj zooplanktonu Starolesnianskeho plesa (Vysoké Tatry, Slovensko) v kontextu globálních změn / Historical development of zooplankton of the Starolesnianske lake (the High Tatra Mountains, Slovakia) in the context of global changes Blechová, Magdalena January 2016 (has links) The aims of the thesis were to document the history of the Cladocera (Crustacea) community structure in the Starolesnianske Lake (the High Tatra Mountains, Slovakia) with regards to environmental changes (e. g., Medieval Warm Period, Little Ice Age, anthropogenic acidification, recovery from acidification), and to analyze in detail the development of zooplankton (Cladocera, Copepoda, Rotifera) during the peaking acidification and recovery from acidification (1978 - 2015). Based on results of both the approaches, the appropriateness of using historical data on zooplankton in Tatra lakes between 1909 - 1913 (Minkiewicz, 1914) as a reference condition for the evaluating biological recovery from acidification should have been assessed. The methods used were paleolimnological analyses of lake sediment (namely subfossil Cladocera), analysis of recent zooplankton, and analyses of lake water chemistry. It was found that in the historical record, relative abundances of Cladocera species significantly changed cca 150 years ago (at the end of the Little Ice Age and, in the main, in the period of anthropogenic acidification). The lake, though, has had a very stable species composition of Cladocera during the last cca 2,000 years, represented by four species: Alona quadrangularis, Alonella excisa, Ceriodaphnia...
17	Environmental Change and Molluscan Death Assemblages: An Assessment of Ecological History Along a Carbonate Bank in Florida Bay Ferguson, Chad Allen 06 November 2009 (has links) No description available. Biology Earth Ecology Environmental Science Geology Paleoecology Paleontology molluscan death assemblages subfossil carbonate bank body size sea shell mollusk coastal monitoring seagrass bed environmental change anthropogenic nutrient enrichment coastal environment Thalassia Halodule Cerithium Florida Bay
18	Makrofossilanalys som ekologiskt verktyg : En metodutvärdering Pettersson, Siri January 2017 (has links) Approximately 50 percent of all endangered species in Scandinavia are associated with old agricultural landscapes. During the agricultural industrialization of the past century the traditional practices and methods that created these environments have been phased out. This has brought on a serious decline and fragmentation of biomes that many endangered species depend on. Knowledge of traditional agricultural landscapes and their species dynamics is needed to make well informed decisions regarding their care and restoration. One way to acquire such knowledge is to study fossil plant remnants from old agricultural contexts. In this study sub-fossil Cyperaceae achenes were analyzed in an attempt to identify them. The achenes had been preserved in three Iron Age wells (80-980 AD) at the Gilltuna settlement in central Sweden and were found during an archeological investigation in 2010. The purpose of this study was to identify the achenes to species level, make conclusions about the ecology of the surrounding landscape, and construct simple species identification key as well as evaluate archaeobotany as an ecological tool. The identification attempt resulted in 14 determined species, which were in consistency with previous landscape analyses made using ecological species distribution. The resulting identification key is a suggestion, to be expanded in the future. This method can undoubtedly provide further knowledge of prehistoric and historical biomes, but in order to draw useful conclusions the identification technique further as well as knowledge of present regional ecology must be developed, especially concerning different Cyperaceae species‟ response to different kinds of stress. macro fossil analysis cyperaceae sedge seed archaeobotanic paleo ecology sweden conservation makrofossilanalys arkeobotanik paleoekologi växtekologi ekologi historisk ekologi cyperaceae halvgräs makrofossil subfossil achen nöt frukt frö metodutvärdering artidentifiering identifiering järnålder vikingatid romersk järnålder Gilltuna västerås län naturvård äng ängsmark hage gräsmark Ecology Ekologi Botany Botanik Archaeology Arkeologi
19	The comparative biology of Fluttering shearwater and Hutton's shearwater and their relationship to other shearwater species Wragg, Graham January 1985 (has links) The discovery and taxonomic history of fluttering shearwater (Puffinus gavia (Forster) and Hutton's shearwater (Puffinus huttoni Mathews) are reviewed. Taxonomic theory, where appropriate to this thesis, is discussed. The external morphology of P. gavia and P. huttoni is compared. No single external measurement or plumage character separates more than 60% of birds examined. The best system of identification is to compare the ratio of different body parts within an individual bird. The distribution of P. gavia and P. huttoni is compared. Hutton's shearwater feeds further out to sea and it is believed to be a migrant species wintering in north west Australian waters. The fluttering shearwater is believed to be a semi-migrant species with only the juveniles spending time in south east Australia. The red cell enzymes of P. gavia, P. huttoni and P. griseus are compared. There are differences in two esterase loci between gavia and huttoni, while P. griseus is more distantly related. Nei's genetic identity values are calculated. The systematic value of electrophoretic data is discussed. The relationship of an undescribed subfossil shearwater to P. gavia and P. huttoni is discussed. An outgroup analysis to other shearwater species is carried out according to phylogenetic (cladistic) theory. The subfossil shearwater is most closely related to the fluttering shearwater, and these two form a sister group to Hutton's shearwater. These three species are a sister group of P. opisthomelas. The relationship between the many P. assimilis subspecies, the black-backed Manx shearwaters, and the gavia, huttoni and opisthomelas group was not resolved. Puffinus nativitatis is more closely related to the Manx and the little shearwaters than to the P. griseus, P. tenuirostris group. Procellariidae Puffinus phylogenetics Puffinus gavia Puffinus huttoni undescribed subfossil shearwater comparative biology comparative osteology red cell enzymes Nei's genetic identities Hutton's shearwater Fluttering shearwater

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