The Relationship of Bog Stratigraphy to Climatic Change and Archaeology

1946 ◽  
Vol 12 ◽  
pp. 1-11 ◽  
Author(s):  
H. Godwin
Keyword(s):  
Climatic Change ◽  
Plant Communities ◽  
Aquatic Plant ◽  
Plant Remains ◽  
Relationship Of ◽  
Lake Deposits ◽  
The Relationship ◽  
Peat Stratigraphy

As a botanical field investigator for many years past interested in bogs and fens I have often had occasion to notice that these areas appeal very differently to different persons: to some I fear they do not appeal at all, and I fancy that many an archaeologist at heart prefers the dry chalk trench to the soaking black peat face. There are, however, such great advantages to be gained from the study of peat and lake-deposits in relation to archaeology that archaeologists increasingly realise the need for much fuller knowledge of the inherent character and properties of these deposits. Since such deposits are formed by the accumulation of plant-remains under water-logged conditions, and thus incorporate the remains of past generations of aquatic plant communities, it is evident that we shall need to consider the peat beds from the standpoint of the plant-ecologist already familiar with corresponding communities as they grow and form peat at the present day. It is therefore chiefly as an ecologist that I have sought to understand the problems offered by peat stratigraphy, and it is as such that I hope to convey something of the problems they concern.

scholarly journals A phytosociological survey of aquatic vegetation in the main freshwater lakes of Greece

2020 ◽  
Vol 1 ◽  
pp. 53-75
Author(s):  
Dimitrios Zervas ◽  
Ioannis Tsiripidis ◽  
Erwin Bergmeier ◽  
Vasiliki Tsiaoussi
Keyword(s):  
Plant Communities ◽  
Aquatic Plant ◽  
Aquatic Vegetation ◽  
Environmental Parameters ◽  
Hierarchical Cluster ◽  
Freshwater Lake ◽  
Vegetation Types ◽  
Freshwater Lakes ◽  
Lake Ecosystems ◽  
The Relationship

Aims: This study aims to contribute to the knowledge of European freshwater lake ecosystems with updated and new information on aquatic plant communities, by conducting national-scale phytosociological research of freshwater lake vegetation in Greece. Moreover, it investigates the relationship between aquatic plant communities and lake environmental parameters, including eutrophication levels and hydro-morphological conditions. Study area: Lakes in Greece, SE Europe. Methods: 5,690 phytosociological relevés of aquatic vegetation were sampled in 18 freshwater lake ecosystems during 2013–2016. The relevés were subjected to hierarchical cluster and indicator species analyses in order to identify associations and communities of aquatic vegetation, as well as to describe their syntaxonomy. Multiple regression analysis was applied to investigate the relationship between vegetation syntaxa and environmental parameters of lakes, i.e. physico-chemical parameters and water level fluctuation. Results: Ninety-nine plant taxa belonging to 30 different families were recorded. Forty-six vegetation types were identified and described by their ecological characteristics, diagnostic taxa and syntaxonomical status. Thirteen vegetation types, the largest number belonging to the vegetation class Charetea, are considered to be new records for Greece. The distribution of the vegetation types recorded in the 18 freshwater lakes was found to depend on environmental parameters and levels of eutrophication. Conclusions: An updated aquatic vegetation inventory was produced for Greek lakes, and primary results showed that the presence/absence of aquatic plant communities and the community composition in freshwater lakes can be utilized to assess the pressure of eutrophication on lake ecosystems. Taxonomic reference: Euro+Med (2006–). Abbreviations: MNT = Mean number of taxa; WFD = Water Framework Directive.

Plant diversity and storage at Mandalo, Macedonia, Greece: archaeobotanical evidence from the Final Neolithic and Early Bronze Age

2003 ◽  
Vol 98 ◽  
pp. 1-35 ◽  
Author(s):  
Soultana M. Valamoti ◽  
Glynis Jones
Keyword(s):  
Bronze Age ◽  
Wild Plant ◽  
Early Bronze Age ◽  
Crop Failure ◽  
Plant Resources ◽  
Animal Dung ◽  
Bitter Vetch ◽  
Plant Remains ◽  
Relationship Of ◽  
The Relationship

The charred plant remains from Final Neolithic and Early Bronze Age levels at Mandalo, Macedonia, Greece provide evidence for a broad range of crops and wild plant resources. There is clear evidence for the storage of some of these, in particular emmer, lentils and bitter vetch, but also barley, einkorn, Celtic bean, grass pea and acorns. There is also evidence for the possible storage and use of animal dung fuel, which has not previously been reported for Greece, and for the cultivation of flax dating back to the 5th millennium BC. The diversity of plant resources will have provided a ‘buffering mechanism’ against occasional crop failure, and the relationship of this to the proposed ‘marginal colonization’ of Greece is discussed. On the basis of the species found in animal dung, it is suggested that the arable and pastoral sectors were integrated, with relatively small numbers of animals grazed locally on stubble or fallow fields.

scholarly journals Алелопатичні зв’язки спірохет Leptospira Interrogans у фітоценозах болотистих лук

2013 ◽  
pp. 43-44
Author(s):  
В. В. Гулай
Keyword(s):  
Plant Communities ◽  
Higher Plants ◽  
Steppe Zone ◽  
Water Soluble ◽  
Forest Steppe ◽  
Leptospira Interrogans ◽  
Vegetation Types ◽  
Negative Effect ◽  
Relationship Of ◽  
The Relationship

Наводяться відомості щодо особливостей екологічних взаємозв’язків вищих рослин та патогенних лептоспір в умовах фітоценозів болотистих лукЛісосотепу України. Основою екологічного впливу представників рослинності зазначених біотопів на спірохет є топічний тип біотичних зв’язків, щопроявляється у виділенні водорозчинних алелопатичноактивних речовин, як живими рослинами, так і з їх залишків. У цілому фонові види рослинності проявляють негативну дію на збудника лептоспірозу, що зменшує час перебування цих спірохет у фітоценозах болотистих лук. There is information on the environmental characteristics of the relationship of higher plants and pathogenic leptospirs in plant communities marshy meadows Forest-Steppe zone of Ukraine. The basis of the environmental impact of these representatives vegetation habitats for spirochetes are topical type of biotic linkages, resulting in the allocation of water-soluble substances allelopathy activity as living plants and their residues. In general, background vegetation types show a negative effect on the pathogen leptospirosis, which reduces the time spent in these spirochetes phytocenoses marshy meadows.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

The relationship of IGE receptor topography to signaling activity in RBL-2H3 mast cells

1991 ◽  
Vol 49 ◽  
pp. 236-237
Author(s):  
J.R. Pfeiffer ◽  
J.C. Seagrave ◽  
C. Wofsy ◽  
J.M. Oliver
Keyword(s):  
Mast Cells ◽  
Protein A ◽  
Scattered Electron ◽  
Ige Receptor ◽  
Receptor Complexes ◽  
Ige Binding ◽  
Electron Imaging ◽  
Small Clusters ◽  
Relationship Of ◽  
The Relationship

In RBL-2H3 rat leukemic mast cells, crosslinking IgE-receptor complexes with anti-IgE antibody leads to degranulation. Receptor crosslinking also stimulates the redistribution of receptors on the cell surface, a process that can be observed by labeling the anti-IgE with 15 nm protein A-gold particles as described in Stump et al. (1989), followed by back-scattered electron imaging (BEI) in the scanning electron microscope. We report that anti-IgE binding stimulates the redistribution of IgE-receptor complexes at 37“C from a dispersed topography (singlets and doublets; S/D) to distributions dominated sequentially by short chains, small clusters and large aggregates of crosslinked receptors. These patterns can be observed (Figure 1), quantified (Figure 2) and analyzed statistically. Cells incubated with 1 μg/ml anti-IgE, a concentration that stimulates maximum net secretion, redistribute receptors as far as chains and small clusters during a 15 min incubation period. At 3 and 10 μg/ml anti-IgE, net secretion is reduced and the majority of receptors redistribute rapidly into clusters and large aggregates.

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