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  • 1
    Language: English
    In: Holocene (Sevenoaks), 2016-02, Vol.26 (2), p.205-221
    Description: The sediment of Lake Çubuk in NW Anatolia, which is situated very close to the climate boundary between the dry Central Anatolia and the wet Marmara region, is regarded as a suitable climate archive to test inward and outward movements of this boundary in accordance with past climate variations. Herein, we study the stratigraphic record of the last 2800 years of this landslide-dammed lake at 1030 m elevation, using multi-proxy tools (sedimentology, major and trace element geochemistry, stable isotopes, pollen, diatoms and ostracods) and compare the results with other contemporaneous Anatolian climatic records. Our findings indicate that Lake Çubuk recorded seven distinct climatic periods in the last 2800 years that have been previously revealed elsewhere in Anatolia. The most arid period occurred at the end of the Near-East Aridification Phase at approximately 200 BC when the δ18O shifted to very negative values, and the planktonic diatom ratio considerably decreased. The Dark Ages and the late Byzantine periods between AD 670 and 1070 are characterized by more positive δ18O values, increasingly higher lake levels and the most extensive arboreal cover of the entire record. The ‘Little Ice Age’ appeared suddenly, within 40 years, at AD 1350 and is reflected in all of the proxies, including a positive shift in δ18O, a sharp decrease in pollen of shrub and herb to the benefit of pine trees and a rapid increase in benthic diatom abundance indicating a lake level shallowing. In many parts of the record, a close match between the stable isotopes and the pollen assemblage zones in the last 2800 years demonstrates that climate rather than human activity was the primary driver of vegetation cover in this mid-altitude mountain of NW Anatolia.
    ISSN: 0959-6836
    E-ISSN: 1477-0911
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
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  • 2
    Language: English
    In: Journal of biogeography, 2007-12-01, Vol.34 (12), p.2115-2128
    Description: Aim To generate maps of potential refugia for summer-green trees during the Last Glacial Maximum (LGM). Locations Southern Europe and south-western Asia. Methods Time-slice simulations of the atmospheric climate with the ECHAM3 model are used for the LGM. Limiting factors beyond which cool and warm groups of deciduous trees cannot grow (such as temperature in growing degree days, minimum monthly temperature and precipitation in summer) are chosen. A limited validation by fossil pollen and charcoal records from LGM sites was done. Results Two sets of maps extending from Europe to the Caspian region for cool and warm summer-green trees are presented. Three criteria are combined using contour lines to indicate confidence levels. Small areas within the three southern peninsulas of Europe (Spain, Italy and Greece) are highlighted as possible refugia for summer-green trees. Further, areas that have remained poorly known are now proposed as refugia, including the Sakarya-Kerempe region in northern Turkey, the east coast of the Black Sea and the area south of the Caspian Sea. Main conclusions The maps produced in this study could be used to facilitate better long-term management for the protection of European and south-western Asian biodiversity.
    Subject(s): Trees ; Simulations ; Precipitation ; Paleoclimatology ; Tree growth ; Seas ; Refuge habitats ; Deciduous trees ; Climate models ; Pollen ; Refugia Revealed ; glacial refugia ; palynology ; climatic model ; Europe ; summer‐green trees ; LGM climate ; Biodiversity ; Fundamental and applied biological sciences. Psychology ; Biological and medical sciences ; General aspects ; Synecology ; Animal and plant ecology ; Animal, plant and microbial ecology
    ISSN: 0305-0270
    E-ISSN: 1365-2699
    Source: Alma/SFX Local Collection
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  • 3
    Language: English
    In: The Journal of eukaryotic microbiology, 2017-11, Vol.64 (6), p.829-842
    Description: We investigate the cyst‐theca relationship of Impagidinium caspienense. Through an incubation experiment, we succeeded in examining the motile stage. Additional molecular analysis of single‐cyst PCR (LSU and SSU rDNA) reveal that the cyst is related to the species Gonyaulax baltica Ellegaard et al. (). The ability of this species to belong to two types of cyst‐based genera (spiniferate and impagidinioid) suggests that environmental (particularly salinity) and not genetic factors explain the formation of both morphotypes by G. baltica, which provides evidence for heterospory in this species. The affiliation to G. baltica demonstrates that I. caspienense is not endemic to the Caspian Sea. The phylogenetic position of several other gonyaulacoid species is also documented: Impagidinium pallidum, Ataxiodinium choane, Pyxidinopsis psilata, Spiniferites belerius, and Spiniferites ramosus. The LSU and SSU rDNA based phylogenies suggest that the genera Impagidinium and Spiniferites are not monophyletic, and that P. psilata and A. choane are close to Gonyaulax verior and Gonyaulax polygramma, respectively. In addition, this study accentuates the importance of cyst morphology in the classification of the Gonyaulacales.
    Subject(s): salinity ; Pyxidinopsis psilata ; Impagidinium pallidum ; Ataxiodinium choane ; Spiniferites belerius ; Baltic Sea ; Spiniferites ramosus ; Oceans and Seas ; RNA, Ribosomal, 18S - genetics ; Phylogeny ; DNA, Ribosomal - chemistry ; RNA, Ribosomal - genetics ; Sequence Analysis, DNA ; Locomotion ; Dinoflagellida - genetics ; Microscopy ; Dinoflagellida - isolation & purification ; Polymerase Chain Reaction ; DNA, Protozoan - genetics ; Geologic Sediments - parasitology ; DNA, Protozoan - chemistry ; Dinoflagellida - physiology ; Dinoflagellida - classification ; Cluster Analysis ; DNA, Ribosomal - genetics ; Analysis ; Sediments (Geology) ; Salinity ; Index Medicus
    ISSN: 1066-5234
    E-ISSN: 1550-7408
    Source: Alma/SFX Local Collection
    Source: © ProQuest LLC All rights reserved〈img src="https://exlibris-pub.s3.amazonaws.com/PQ_Logo.jpg" style="vertical-align:middle;margin-left:7px"〉
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  • 4
    Language: English
    In: Holocene (Sevenoaks), 2016-01, Vol.26 (1), p.3-16
    Description: Caspian Sea level has undergone significant changes through time with major impacts not only on the surrounding coasts but also on offshore. This study reports a brackish water invasion on the southern coast of the Caspian Sea constructed from a multi-proxy analysis of sediment retrieved from the Langarud wetland. The ground surface level of wetland is 〉6 m higher than the current Caspian Sea level (at −27.41 m in 2014) and located 〉11 km far from the coast. A sequence covering the last millennium was dated by three radiocarbon dates. The results from this new study suggest that Caspian Sea level rose up to at least −21.44 m (i.e. 〉6 m above the present water level) during the early ‘Little Ice Age’. Although previous studies in the southern coast of the Caspian Sea have detected a high-stand during the Little Ice Age period, this study presents the first evidence that this high-stand reached so far inland and at such a high altitude. Moreover, it confirms one of the very few earlier estimates of a high-stand at −21 m for the second half of the 14th century. The effects of this large-scale brackish water invasion on soil properties would have caused severe disruption to regional agriculture, thereby destabilising local dynasties and facilitating a rapid Turko-Mongol expansion of Tamerlane’s armies from the east.
    ISSN: 0959-6836
    E-ISSN: 1477-0911
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
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  • 5
    Language: English
    In: Holocene (Sevenoaks), 2014-10-01, Vol.24 (10), p.1226-1252
    Description: New palynological and ostracod data are presented from the Holocene Volga delta, obtained from short cores and surface samples collected in the Damchik region, near Astrakhan, Russian Federation in the northern Caspian Sea. Four phases of delta deposition are recognized and constrained by accelerated mass spectrometry (AMS) radiocarbon ages. Palynological records show that erosive channels, dunes (Baer hills) and inter-dune lakes were present during the period 11,500–8900 cal. BP at the time of the Mangyshlak Caspian lowstand. The period 8900–3770 cal. BP was characterized regionally by extensive steppe vegetation, with forest present at times with warmer, more humid climates, and with halophytic and xerophytic vegetation present at times of drought. The period 3770–2080 cal. BP was a time of active delta deposition, with forest or woodland close to the delta, indicating relatively warm and humid climates and variable Caspian Sea levels. From 2080 cal. BP to the present-day, aquatic pollen is frequent in highstand intervals and herbaceous pollen and fungal hyphae frequent in lowstand intervals. Soils and incised valley sediments are associated with the regional Derbent regression and may be time-equivalent with the ‘Medieval Warm Period’. Fungal spores are an indicator of erosional or aeolian processes, whereas fungal hyphae are associated with soil formation. Freshwater algae, ostracods and dinocysts indicate mainly freshwater conditions during the Holocene with minor brackish influences. Dinocysts present include Spiniferites cruciformis, Caspidinium rugosum, Impagidinium caspienense and Pterocysta cruciformis, the latter a new record for the Caspian Sea. The Holocene Volga delta is a partial analogue for the much larger oil and gas bearing Mio-Pliocene palaeo-Volga delta.
    Subject(s): Archaeology ; dinoflagellate cysts and ostracods ; Caspian Sea ; sea level change ; vegetation and climate ; Volga delta ; Global and Planetary Change ; Ecology ; Earth-Surface Processes ; pollen and spores ; Palaeontology
    ISSN: 0959-6836
    E-ISSN: 1477-0911
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
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  • 6
    Language: English
    In: Geological journal (Chichester, England), 2018-11, Vol.53 (6), p.2427-2436
    Description: Clay minerals are useful tools for reconstructing palaeoclimatic history. The clay mineral composition and total organic carbon (TOC) of the Pliocene Productive Series from the western South Caspian Basin was used to reconstruct palaeoclimate on the adjacent land, which still remains a data‐poor area. Variations of the smectite and illite contents in the Lower Division of the Productive Series suggest that two different climatic conditions alternated on the Russian Platform. High amount of illite combined with low amount of smectite and low amount of TOC indicate arid climatic condition. In contrast, high amount of smectite and TOC with low amount of illite suggest humid climatic condition on the Russian Platform. The Upper Division of the Productive Series in the Absheron Peninsula is characterized by high amount of illite, which indicates arid climatic conditions. Similarly, variable smectite and illite contents in the Upper Division of the Productive Series in the South Absheron Offshore Zone imply a climate alternating between aridity and humidity in the Greater Caucasus. This investigation contributes to the knowledge of the Pliocene at the boundary between Europe and Asia, in a continental setting and at a key period of climatic changes, such as the mid‐Pliocene warm period and the beginning of the Northern Hemisphere glacial–interglacial cycles.
    Subject(s): Caspian Sea ; Clay minerals ; TOC ; Pliocene Productive Series ; palaeoclimate ; Environmental Sciences
    ISSN: 0072-1050
    E-ISSN: 1099-1034
    Source: Alma/SFX Local Collection
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  • 7
    Language: English
    In: Geophysical research letters, 2019-04-16, Vol.46 (7), p.3944-3952
    Description: The responses of the Indian and East Asian summer monsoons (ISM and EASM) to warming since the last deglaciation are controversial. Pollen results from a subalpine lake in the ISM area show that the Tsuga dumosa forest zone migrated at least 650 m upward during 18.6–7.1 kyr BP, indicating a gradual rise in mean annual temperature exceeding 3.9 °C. In response, grasses and deciduous and evergreen broad‐leaved trees successively colonized the mountainous environment. By contrast, the area around a lake in the EASM area was gradually occupied by temperate deciduous trees. In both areas, the maximum monsoonal precipitation occurred during 7.1–6.4 kyr BP, coinciding with peak Holocene warmth, but lagging the peak in Northern Hemisphere summer insolation by 3.9–4.6 kyr, due to delayed ice melting in northern high latitudes. Our results indicate the synchronous strengthening of the ISM and EASM in response to warming‐induced northward shifts in the Intertropical Convergence Zone. Plain Language Summary The responses of the Indian summer monsoon (ISM) and East Asian summer monsoon to past global warming provide valuable insights into future climate scenarios. A paleovegetation reconstruction from the ISM area shows a gradual warming of over 3.9 °C in mean annual temperature from 18.6 to 7.1 kyr BP. The ISM and East Asian summer monsoon strengthened synchronously in response to warming‐induced shifts in the Intertropical Convergence Zone and reached their peak at 7.1–6.4 kyr BP, lagging the summer insolation maximum by 3.9–4.6 kyr, due to delayed ice melting in northern high latitudes. As future warming continues, the loss of habitat for Tsuga dumosa and other alpine species will accelerate in the ISM area, and the abundance of deciduous trees will increase in northern China. Key Points Pollen data show a minimum 650‐m upward migration of the Tsuga dumosa forest zone in the Hengduan Mountains from 18.6 to 7.1 kyr BP Our data and a synthesis of 37 additional paleovegetation records show the peak of the Holocene Climate Optimum occurring around 7 kyr BP The Indian and East Asian summer monsoons strengthened synchronously in response to past global warming
    Subject(s): Asian summer monsoon ; last deglaciation ; pollen records ; lake sediments ; Holocene ; Climatology ; Earth Sciences ; Sciences of the Universe ; Environmental Sciences ; Global Changes
    ISSN: 0094-8276
    E-ISSN: 1944-8007
    Source: Alma/SFX Local Collection
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  • 8
    Language: English
    In: Palaeobiodiversity and palaeoenvironments, 2018-12, Vol.98 (4), p.653-662
    Description: The early Pleistocene site at Bòvila Ordis (Banyoles-Besalú Basin in NE Iberia) delivered in the past a significant pollen succession which can be assigned to the upper Matuyama geomagnetic chron owing to the identification of the Cobb Mountain magnetic subchron (1.2 Ma ago). It has been previously shown by palynology that the succession of lakes recorded at Bòvila Ordis corresponds to a succession of late early Pleistocene glacial–interglacial phases, between 1.2 and 1 Ma, which can be correlated with MIS 35, 33 and 31. The present investigation focuses on lake 1 (borehole BOIV) and lake 3 (boreholes BOI, BOII and BOIII and outcrops) from this site, where both fossil pollen and rodent teeth were recovered together in the same sediment, and offers the potential to provide a vegetation and climatic context to sites that are dated by rodent teeth, such as some hominin sites in Western Europe. Here we analyse the rodent content and their biostratigraphical implications in the context of early hominin dispersal in Western Europe. In lake 1, pollen data had revealed in previous analysis a complete glacial–interglacial cycle and parts of a second one. The uppermost part of BOIV sequence yielded rodent remains that can be assigned to the arvicolid species Allophaiomys chalinei and Mimomys cf. savini. Previous palynological investigations from lake 3 had revealed a temperate deciduous forest, indicative of warm and humid conditions. At the top of the section of lake 3, a regression of the forest and the spread of open landscape elements indicated drier, more steppic conditions. The palaeobiological record of lake 3 includes pollen and large (Cervus philisi, Hippopotamus antiquus and Equus stenonis) and small mammal remains (Mimomys savini and Allophaiomys lavocati). The rodent material from lake 1 clearly indicates an early Pleistocene age somewhat older than that of lake 3. According to these new biostratigraphic data in the context of previous palynological and chronological data, it is clear that Allophaiomys chalinei entered Iberia before 1 Ma ago and A. lavocati remained until 1 Ma ago. The fact that Allophaiomys lavocati and Allophaiomys chalinei, two arvicolids currently associated with the earliest evidence of hominin presence in Western Europe, appear in Bòvila Ordis at a time of mild, temperate conditions reinforce the idea that the first hominin dispersal in this region was strongly dependent on favourable climatic conditions.
    Subject(s): Earth Sciences ; Plant Systematics/Taxonomy/Biogeography ; Early Pleistocene ; Europe ; Freshwater & Marine Ecology ; Biodiversity ; Palaeoclimatology ; Rodent ; Paleontology ; Animal Systematics/Taxonomy/Biogeography ; Biostratigraphy ; Life Sciences
    ISSN: 1867-1594
    E-ISSN: 1867-1608
    Source: Alma/SFX Local Collection
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  • 9
    Language: English
    In: Quaternary science reviews, 2009, Vol.28 (25), p.2616-2632
    Description: High-resolution palynological analysis of a 38-cm long core collected from Lake Sapanca, northwest Turkey, reveals large earthquakes that occurred during the second half of the 20th century along the North Anatolian Fault Zone. Four events have disturbed the lacustrine sedimentary sequence. Three of the four events are historical earthquakes in 1999 in Izmit, 1967 in Mudurnu and 1957 in Abant. These events are recorded in the core by turbiditic deposits and reworked sediment and by low overall palynomorph concentrations but high values of thick-exined pollen, fern spores and fungal spores. Palynomorphs in the event beds have been grouped based on their associations in modern moss, river and lake samples. The inferred mechanisms of transport and sources for the palynomorphs are: 1- lake sediment displaced by slump, 2- collapsed shoreline sediment owing to seiche, waves and sudden lake level changes, 3- subsidence of deltas and 4- river-transported soil and sediment from upland areas. The 1999 Izmit earthquake is only weakly recorded by palynomorphs, probably due to recent engineering control on the rivers. The 1967 Mudurnu earthquake had the strongest effect on the lake, introducing successive packages of sediment to the centre of the lake from underwater slopes, the lakeshore and rivers.
    Subject(s): Deltas ; Rivers ; Earthquakes ; Seismology ; Microfossils ; Sediments (Geology)
    ISSN: 0277-3791
    E-ISSN: 1873-457X
    Source: Backfile Package - All of Back Files EBS [ALLOFBCKF]
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  • 10
    Language: English
    In: Theoretical and applied climatology, 2019-04-12, Vol.136 (1), p.475-488
    Description: With a fall of the Caspian Sea level (CSL), its size gets smaller and therefore the total evaporation over the sea is reduced. With a reduced evaporation from the sea, the fall of the CSL is weakened. This creates a negative feedback as less evaporation leads to less water losses of the Caspian Sea (CS). On the other hand, less evaporation reduces the water in the atmosphere, which may lead to less precipitation in the catchment area of the CS. The two opposite feedbacks are estimated by using an atmospheric climate model coupled with an ocean model only for the CS with different CS sizes while keeping all other forcings like oceanic sea surface temperatures (SSTs) and leaf area index the same from a global climate simulation. The investigation is concentrated on the medieval period because at that time the CSL changed dramatically from about − 30 to − 19 m below the mean ocean sea level, partly man-made. Models used for simulating the last millennium are not able to change the size of the CS dynamically so far. When results from such simulations are used to investigate the CSL variability and its causes, the present study should help to parameterize its feedbacks.A first assumption that the total evaporation from the CS will vary with the size of the CS (number of grid points representing the sea) is generally confirmed with the model simulations. The decrease of grid points from 15 to 14, 10, 8 or 7 leads to a decrease of evaporation to 96, 77, 70 and 54%. The lower decrease than initially expected from the number of grid points (93, 67, 53 and 47%) is probably due to the fact that there would also be some evaporation at grid points that run dry with a lower CSL but a cooling of the CS SST with increasing CS size in summer may be more important. The reduction of evaporation over the CS means more water for the budget of the whole catchment of the CS (an increase of the CSL) but from the gain through reduced evaporation over the CS, only 70% is found to remain in the water budget of the whole catchment area due to feedbacks with the precipitation. This suggests a high proportion of recycling of water within the CS catchment area.When using a model which does not have a correct CS size, the effect of a reduced CS area on the water budget for the whole CS catchment can be estimated by taking the evaporation over the sea multiplied by the proportional changed area. However, only 50% of that change is ending up in the water balance of the total catchment of the CS. A formula is provided. This method has been applied to estimate the CSL during the Last Glacial Maximum to be at − 30 to − 33 m.The experiments show as well that the CS has an impact on the large-scale atmospheric circulation with a widened Aleutian 500 hPa height field trough with increasing CS sizes. It is possible to validate this aspect with observational data.
    Subject(s): Climatology ; Earth Sciences ; Atmospheric Sciences ; Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution ; Atmospheric Protection/Air Quality Control/Air Pollution ; Water balance (Hydrology) ; Atmospheric circulation ; Climate ; Models ; Precipitation (Meteorology) ; Analysis ; Sciences of the Universe
    ISSN: 0177-798X
    E-ISSN: 1434-4483
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
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