Multiple crises before the big crisis: Early Messinian Eastern Mediterranean paleoclimate reconstruction inferred from biomarkers and stable isotopes (Crete, Greece)

Author(s):  
Geanina-Adriana Butiseaca ◽  
Marcel T. J. van der Meer ◽  
Giorgos Kontakiotis ◽  
Konstantina Agiadi ◽  
Assimina Antonarakou ◽  
...  

<p>Messinian Mediterranean (7.24‒5.33 Ma) was a highly dynamic environment governed by global climatic and regional tectonic activity. The impact of these two environmental factors is highly distinguishable especially during the latest Messinian (5.97–5.33 Ma), when the famous Messinian salinity crisis (MSC) affected the Mediterranean realm. However, the interplay between climate and tectonics is less studied for the earliest Messinian. Here we use biomarker analysis, coupled with compound-specific hydrogen (δ<sup>2</sup>H) and carbon isotopes (δ<sup>13</sup>C), to track changes in the hydrological budget, mean annual air temperature (MAAT), vegetation and reconstruct the sea-land climate conditions in Eastern Mediterranean between 7.2‒6.5 Ma. Our data from Agios Myron section on Crete (Greece) confirms a series of drastic environmental changes in the Eastern Mediterranean during the mentioned time interval. δ<sup>2</sup>H values of alkenones indicate highly evaporitic events accompanied by shifts in vegetation, from dominant >C<sub>3</sub> plants to marked increasing dominance of C<sub>4</sub>, with recurrence of C<sub>3</sub> vegetation at ~6.99 and 6.78 Ma respectively. The MAAT data indicate average values of 14⁰C and the overall trend suggests an orbitally paced continental climate, with maximum temperatures registered during eccentricity maxima. The reconstructed paleo-soil pH record follows a stepwise increasing trend towards slightly-alkaline soils, supporting an enhanced open vegetation contribution resulting from the ongoing continentalisation. These results provide new insights into the Messinian environmental conditions of the Mediterranean Sea, suggesting an ongoing restriction after 7 Ma, with multiple restrictive phases marked by increasing intensity until the final MSC event.</p>

2021 ◽  
pp. 1-8
Author(s):  
Thaísa Araújo ◽  
Helena Machado ◽  
Dimila Mothé ◽  
Leonardo dos Santos Avilla

Abstract Climatic and environmental changes, as well as human action, have been cited as potential causes for the extinction of megafauna in South America at the end of the Pleistocene. Among megamammals lineages with Holarctic origin, only horses and proboscideans went extinct in South America during this period. This study aims to understand how the spatial extent of habitats suitable for Equus neogeus and Notiomastodon platensis changed between the last glacial maximum (LGM) and the middle Holocene in order to determine the impact that climatic and environmental changes had on these taxa. We used species distribution modeling to estimate their potential extent on the continent and found that both species occupied arid and semiarid open lands during the LGM, mainly in the Pampean region of Argentina, southern and northeastern Brazil, and parts of the Andes. However, when climate conditions changed from dry and cold during the LGM to humid and warm during the middle Holocene, the areas suitable for these taxa were reduced dramatically. These results support the hypothesis that climatic changes were a driving cause of extinction of these megamammals in South America, although we cannot rule out the impact of human actions or other potential causes for their extinction.


2018 ◽  
Author(s):  
Abir Fersi ◽  
Nawfel Mosbahi ◽  
Ali Bakalem ◽  
Jean-Philippe Pezy ◽  
Alexandrine Baffreau ◽  
...  

The Gulf of Gabès on the southern coasts of Tunisia in the central part of the Mediterranean is a very shallow basin, characterized by semidiurnal tides, attaining a range of 2.3 m during spring tides. The intertidal zone was covered by extended Zostera (Zosterella) noltei Hornemann, 1832 beds mainly developed around the Kneiss Islands while tidal channels ensured the water circulation in this sub-tropical environment with very low freshwater input and high summer temperature. In spite of protected conventions, the area remained under high human pressures: overfishing, and the impact of the pollution of the phosphate industry. Intensive sampling in both intertidal and shallow subtidal zones during annual cycles permitted to identify a rich macrofauna which increase considerably the species known in this eastern part of the Mediterranean Sea. More than 50 species are added for the Tunisian fauna. Moreover, patterns of diversity are analysed with the sediment types, presence or absence of Zostera noltei seagrass bed, and human pressures. The list of the collected species are compared with those of surrounding areas in both Western and Eastern Mediterranean Sea.


2012 ◽  
Vol 77 (1) ◽  
pp. 182-191 ◽  
Author(s):  
Bruno Malaizé ◽  
Elsa Jullien ◽  
Amandine Tisserand ◽  
Charlotte Skonieczny ◽  
E. Francis Grousset ◽  
...  

A high resolution analysis of benthic foraminifera as well as of aeolian terrigenous proxies extracted from a 37 m-long marine core located off the Mauritanian margin spanning the last ~ 1.2 Ma, documents the possible link between major continental environmental changes with a shift in the isotopic signature of deep waters around 1.0–0.9 Ma, within the so-called Mid-Pleistocene Transition (MPT) time period. The increase in the oxygen isotopic composition of deep waters, as seen through the benthic foraminifera δ18O values, is consistent with the growth of larger ice sheets known to have occurred during this transition. Deep-water mass δ13C changes, also estimated from benthic foraminifera, show a strong depletion for the same time interval. This drastic change in δ13C values is concomitant with a worldwide 0.3‰ decrease observed in the major deep oceanic waters for the MPT time period. The phase relationship between aeolian terrigeneous signal increase and this δ13C decrease in our record, as well as in other paleorecords, supports the hypothesis of a global aridification amongst others processes to explain the deep-water masses isotopic signature changes during the MPT. In any case, the isotopic shifts imply major changes in the end-member δ18O and δ13C values of deep waters.


2020 ◽  
Author(s):  
Hussam Hag Mohamed Husein ◽  
Wahib Sahwan ◽  
Bernhard Lucke ◽  
Rupert Bäumler

<p><strong>A</strong><strong>bstract</strong></p><p>Knowledge about the genesis and evolution of black soils in the Eastern Mediterranean is vital for sustainable land management as well as for revealing the current and past climate conditions that were decisive for their evolution and development. Hence, it is important to study this type of soil as it only occurs very rarely in the semi-arid region. Answers on the conditions of formation and type of paleoclimate that prevailed during its development can be found in the surrounding environment. In this study, the black soils that currently occur in the Eastern Mediterranean were analyzed in different bioclimatic zones and were found to genetically belong to two soil types: 1-Calcareous black soil (ProperRendzina-Typic Rendolls), 2-Hydromorphic black soil (Haploxerolls). The impact of the relief was obvious on both thickness of the solum and the mollic horizon. Proper Rendzina (Typic Rendolls) occurs on toe slopes and feet slopes, Para-Rendzina (Lithic Rendolls) on shoulders and Chernozems on a flat plain. Regarding the Rendzina, the color reflects the origin of the prevailing parent material from which they are derived: Proper Rendzina forms on limestone, chalk, sandstone, conglomerates, and claystone; Reddish Rendzina on Dolomite and hard limestone, and Grayish Rendzina on Serpentine. It was also found that the Hydromorphic black soils (Haploxerolls, Calcic Chernozems) only occur on calcic marl and lacustrine deposits under saturation conditions and bad drainage in the depressions that formed by the Dead Sea faults. The soil has a thick dark mollic horizon with a high content of organic matter.</p><p><strong>Keywords</strong>: semi-arid, black soil, Rendzina, Chernozems, eastern Mediterranean.</p><p> </p>


2019 ◽  
Vol 62 (2) ◽  
pp. 7-45 ◽  
Author(s):  
Andreas Vött ◽  
Hendrik J. Bruins ◽  
Matthijs Gawehn ◽  
Beverly N. Goodman-Tchernov ◽  
Paolo Marco De Martini ◽  
...  

This article is a response to the publication by Nick Marriner, David Kaniewski, Christophe Morhange, Clément Flaux, Matthieu Giaime, Matteo Vacchi and James Goff entitled "Tsunamis in the geological record: Making waves with a cautionary tale from the Mediterranean", published in October 2017 in Science Advances. Making use of radiometric data sets published in the context of selected palaeotsunami studies by independent research groups from different countries, Marriner et al. (2017) carried out statistical and time series analyses. They compared their results with an assessment of Mediterranean storminess since the mid-Holocene that was previously published by Kaniewski et al. (2016) based on a single-core study from coastal Croatia. Marriner et al. (2017) now present "previously unrecognized" 1500-year "tsunami megacycles" which they suggest correlating with Mediterranean climate deterioration. They conclude that up to 90% of all the 'tsunamis' identified in original tsunami papers used for their study are "better ascribed to periods of heightened storminess". In this response, we show that (i) the comparison of statistical data describing storm and tsunami events presented by Marriner et al. (2017) is incorrect both from a geographical and a statistical point of view, (ii) the assumed periods of central Mediterranean storminess published by Kaniewski et al. (2016) are missing convincing geological and geochronological evidence and are statistically incorrect, (iii) the palaeotsunami data that was originally collected by different groups of authors were manipulated by Marriner et al. (2017) in a way that the resulting data set – used as a benchmark for the entire study of these authors – is wrong and inaccurate, and that (iv) Marriner et al. (2017) did not address or even negate the original sedimentological studies' presentation of comparative tsunami versus storm deposits for the selected individual localities. Based on a thorough and detailed evaluation of the geoscientific background and the methodological approach of the studies by Kaniewski et al. (2016) and Marriner et al. (2017), we conclude that there is no serious and reliable geoscientific evidence for increased storminess in the (central) Mediterranean Sea between 3400 – 2550, 2000 –1800, 1650 –1450, 1300 – 900 and 400 –100 cal BP. The impact of those storms in the Mediterranean, producing geological traces somewhat comparable to those caused by tsunamis, is insignificantly small. For the period 1902 – 2017, Mediterranean tsunamis make up 73 – 98 % of all combined extreme wave events (EWE) leading to coastal flooding and appeared up to 181 times deadlier than comparable storm effects. This is the reason why coastal Mediterranean research has focused on Holocene records of the tsunami hazard, while research on comparable storm effects is of lower significance. The validity of geological evidence for Mediterranean EWE and their interpretation as caused by palaeotsunami impacts thus remains untouched. Tsunamis, in most cases directly and indirectly induced by seismo-tectonics, have always been a much greater threat to Mediterranean coastal regions than comparable storm effects. ' Tsunami megacycles' as expressions of a 1500-year periodicity centered on the Little Ice Age, 1600 and 3100 cal BP that were correlated with questionable storm data do not exist. Cause and effect relationships work the other way round: Major tsunami events, testified by historical accounts, such as those that occurred in 1908 AD, 1755 AD, 1693 AD and 365 AD, induced numerous studies along Mediterranean coasts. These investigations resulted in a large number of publications that specifically focus on those time periods, suspected by Marriner et al. (2017) to bear signs of increased storminess, namely 200 – 300 BP and 1600 BP. The Mediterranean tsunami record cannot be ascribed to periods of increased storminess. On the contrary, the tsunami record as interpreted by the authors of the original papers cited by Marriner et al. (2017), is due to the outstandingly high seismo-tectonic activity of the region. Mediterranean tsunamis are mostly triggered by earthquakes or by earthquake-related secondary effects such as underwater mass movements. The study by Marriner et al. (2017) is also problematic because it includes simple basic statistical mistakes and major methodological inconsistencies. The geomorphological and sedimentary back-ground of EWE deposits was not taken into account. The 'broad brush' approach used by Marriner et al. (2017) to sweep sedimentary deposits from tsunami origin into the storm bag origin, just on the basis of (false) statistics coupled with very broad and unreliable palaeoclimatic indicators and time frames, is misleading. The distortion of original data collected and interpreted by other research groups by Marriner et al. (2017) is particularly disturbing. Their publication is also bound to question in this case the effectiveness of scientific quality assurance in modern publishing commerce. Marriner et al. (2017: 7) talk down the considerable risk to human settlements and infrastructure along Mediterranean coasts in relation to tsunami and earthquake hazards. Their conclusion is not only wrong as a result of their incorrect data mining and analyses, it is also irresponsible with regard to national and international efforts of tsunami and earthquake risk mitigation.


2018 ◽  
Vol 99 (2) ◽  
pp. 361-380 ◽  
Author(s):  
Philippe Ricaud ◽  
Régina Zbinden ◽  
Valéry Catoire ◽  
Vanessa Brocchi ◽  
François Dulac ◽  
...  

Abstract The Gradient in Longitude of Atmospheric Constituents above the Mediterranean Basin (GLAM) airborne campaign was set up to investigate the summertime variability of gaseous pollutants, greenhouse gases, and aerosols between the western (∼3°E) and eastern (∼35°E) sections of the Mediterranean basin as well as how this connects with the impact of the Asian monsoon anticyclone on the eastern Mediterranean in the mid- to upper troposphere (∼5–10 km). GLAM falls within the framework of the Chemistry–Aerosol Mediterranean Experiment (ChArMEx) program. GLAM used the French Falcon-20 research aircraft to measure aerosols, humidity, and chemical compounds: ozone, carbon monoxide, methane, and carbon dioxide. GLAM took place between 6 and 10 August 2014, following a route from Toulouse (France) to Larnaca (Cyprus) and back again via Minorca (Spain), Lampedusa (Italy), and Heraklion (Crete, Greece). The aircraft flew at an altitude of 5 km on its outbound journey and 10 km on the return leg. GLAM also collected vertical profiles around the landing sites listed above. A combination of model outputs, chemical mapping analyses, and spaceborne and surface station measurements gathered prior to and during the campaign were used to interpret the in situ airborne measurements. The main outcome of this study is the impact of intercontinental transport on the longitudinal variability of pollutants, greenhouse gases, and aerosols at an altitude of 10 km. The eastern Mediterranean is affected by air masses from the Arabian Sea surface, and the western Mediterranean is impacted by air masses from North America (biomass burning) and West Africa (desert dust).


2020 ◽  
Vol 22 (Summer 2020) ◽  
pp. 237-255
Author(s):  
Ahmad Alshwawra ◽  
Ahmad Almuhtady

The Mediterranean region has witnessed a lot of turbulence in the last decade. On the one hand, the Arab uprising changed the shape of the regional relations towards more rivalry. On the other hand, the discovery of natural gas resources has opened up a valuable chance for cooperation and settling the long-standing disputes. Jordan is affected by what happens in the Mediterranean region in more than one aspect. The various economic difficulties including energy insecurity, resulting from multiple refugee crises and the interruption of Egyptian gas is one of the most critical challenges Jordan has ever faced. As a heavy energy importer, the Jordanian energy sector is very sensitive to the regional and International context. The recently discovered Eastern Mediterranean gas is an attractive energy resource for Jordan. Nonetheless, a fear of its influence on the Jordanian foreign policy in the Palestinian context has grown. This article discusses the impact of the recent turmoil in the Mediterranean region on Jordan energy security. It tracks the change of energy security in Jordan between 2010 and 2018 using a proposed energy security framework. The article also discusses the potential implications of Jordan’s decision to import the Mediterranean gas through Israel on Jordanian energy security using the proposed energy security framework. Moreover, the article utilizes semi-systematic literature review methodology to analyze international, regional and national contexts in order to investigate the potential ramifications of that decision on Jordanian foreign policy regarding the Palestinian cause.


2011 ◽  
Vol 11 (10) ◽  
pp. 2881-2888 ◽  
Author(s):  
M. Brunetti ◽  
H. Kutiel

Abstract. The impact of the upper level (500 hPa) teleconnection between the North-Sea and the Caspian (NCP) on the temperature and precipitation regimes in the Eastern Mediterranean (EM) have been studied and reported and an index (NCPI) that measures the normalized geopotential heights' differences between the two poles of this teleconnection has been defined. In the present study, the impact of the NCP on the temperature regime over the entire European continent is presented. In particular, the correlation between temperature and the NCPI has been evaluated, on a monthly basis, over the entire Euro-Mediterranean domain for the 1948–2007 period. The results highlight a significant positive correlation in the north-western area of the domain and a significant negative correlation in the south-eastern one. These two poles were also highlighted by comparing the temperature anomalies associated with both phases of NCP. The importance of this sort of NCP-induced temperature bi-pole in the context of temperature variability over Europe and the Mediterranean has been evaluated by applying a Principal Component Analysis to the temperature dataset. The results showed that the temperature bi-pole is associated with the second most important mode of temperature variability over the domain, but if the analysis is restricted to the months associated to NCP (+) and NCP (−), it becomes the first mode with 29.2 % of associated variance.


Inventions ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 33
Author(s):  
Liliana Rusu ◽  
Florin Onea ◽  
Eugen Rusu

A particularity of island areas is that they are subjected to strong sea state conditions that can have a severe impact on the beach stability, while on the other hand, they rely mainly on diesel combustion for electricity production which in the long run is not a sustainable solution. The aim of this work is to tackle these two issues, by assessing the impact of a hybrid marine energy farm that may operate near the north-western part of Giglio Island in the Mediterranean Sea. As a first step, the most relevant environmental conditions (wind and waves) over a 27-year time interval (January 1992–December 2018) were identified considering data coming from both ERA5 and the European Space Agency Climate Change Initiative for Sea State. An overview of the electricity production was made by considering some offshore wind turbines, the results showing that even during the summertime when there is a peak demand (but low wind resources), the demand can be fully covered by five wind turbines defined each by a rated power of 6 MW. The main objective of this work is to assess the coastal impact induced by a marine energy farm, and for this reason, various layouts obtained by varying the number of lines (one or two) and the distance between the devices were proposed. The modelling system considered has been already calibrated in the target area for this type of study while the selected device is defined by a relatively low absorption property. The dynamics of various wave parameters has been analysed, including significant wave height, but also parameters related to the breaking mechanics, and longshore currents. It was noticed that although the target area is naturally protected by the dominant waves that are coming from the south-western sector, it is possible to occur extreme waves coming from the north-west during the wintertime that can be efficiently attenuated by the presence of the marine energy farm.


2018 ◽  
Author(s):  
Abir Fersi ◽  
Nawfel Mosbahi ◽  
Ali Bakalem ◽  
Jean-Philippe Pezy ◽  
Alexandrine Baffreau ◽  
...  

The Gulf of Gabès on the southern coasts of Tunisia in the central part of the Mediterranean is a very shallow basin, characterized by semidiurnal tides, attaining a range of 2.3 m during spring tides. The intertidal zone was covered by extended Zostera (Zosterella) noltei Hornemann, 1832 beds mainly developed around the Kneiss Islands while tidal channels ensured the water circulation in this sub-tropical environment with very low freshwater input and high summer temperature. In spite of protected conventions, the area remained under high human pressures: overfishing, and the impact of the pollution of the phosphate industry. Intensive sampling in both intertidal and shallow subtidal zones during annual cycles permitted to identify a rich macrofauna which increase considerably the species known in this eastern part of the Mediterranean Sea. More than 50 species are added for the Tunisian fauna. Moreover, patterns of diversity are analysed with the sediment types, presence or absence of Zostera noltei seagrass bed, and human pressures. The list of the collected species are compared with those of surrounding areas in both Western and Eastern Mediterranean Sea.


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