Papers by Ioanna Bouloubassi
HAL (Le Centre pour la Communication Scientifique Directe), Dec 15, 2014
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), Apr 27, 2014
water column distribution and carbon isotopic composition of bulk particulate organic carbon,
30th International Meeting on Organic Geochemistry (IMOG 2021), 2021
Summary Brazilian Nordeste is a semi-arid region that is a key area for future South American cli... more Summary Brazilian Nordeste is a semi-arid region that is a key area for future South American climate. Climatic conditions of Nordeste strongly depends on nearby western Atlantic parameters (Temperature, Salinity, etc.). This work aims to improve the understanding of the Nordeste response to hydroclimate and vegetation changes over past interglacial periods (known as odd Marine Isotope Stage, MIS) based on a 17 m long marine sedimentary core (GL1180) collected on the eastern Brazilian continental margin. A multi-proxy approach will be developed by analyzing sedimentary organic matter (OM) at the bulk and molecular levels. Here we present the first results of bulk OM analysis for 135 selected depths with a higher temporal resolution during interglacial periods. Bulk elemental and isotope analyses of OM in sediments from the GL1180 core revealed that the Brazilian Nordeste area experienced notable changes in humidity conditions over the last 300 kyr BP. Complementary lipid biomarker analyses of these samples are in progress to help in the reconstruction of past vegetation and hydroclimate conditions in northeastern Brazil.
Paleoceanography and Paleoclimatology, 2019
The Messinian Salinity Crisis (MSC; 5.97–5.33 Ma) is an enigmatic episode of paleoceanographic ch... more The Messinian Salinity Crisis (MSC; 5.97–5.33 Ma) is an enigmatic episode of paleoceanographic change, when kilometer‐thick evaporite units were deposited in the Mediterranean basin. Here we use geochemical (biomarker and isotope) data to reconstruct sea surface temperature, salinity, and productivity‐preservation changes in the Mediterranean basin just before the MSC. The proxy data indicate that the Mediterranean Sea was significantly saltier and colder between 6.415 and 6.151 Ma, than between 6.151 and 5.971 Ma. Salinity decrease at 6.151 Ma seems to be a relatively fast event just preceding the inception of a warming phase that lasted almost uninterrupted until the MSC onset. The water exchange with the Paratethys could have caused, along with the African rivers, an increased freshwater supply, resulting in normal marine Mediterranean waters between 6.151 and 5.971 Ma, despite the severe restriction of marine connections with the Atlantic at that time. Sea surface temperature ch...
Bulletin of the Geological Society of Greece, 2016
The paleoenviromental conditions during the depositional interval of sapropel S1 in the northeast... more The paleoenviromental conditions during the depositional interval of sapropel S1 in the northeastern Aegean (gravity core M-4, length 2.53 m; south Limnos basin) are studied based on quantitative micropaleontological (benthic and planktonic foraminifera) and geochemical (OC, δ13Corg) analyses. Special feature of core M-4 is the thickness of S1 layer (96 cm). Our study points that sapropelic layer S1a has been deposited in more dysoxic and warmer conditions in respect to S1b. Both primary productivity and preservation of organic material are more intense during the lower part of S1. An interruption of the sapropelic conditions at 8.0 Ka BP which is mainly characterized by the increase of agglutinated foraminiferal forms confirms both higher oxygen bottom conditions and freshwater input.
Biogeosciences Discussions, 2015
Surface sediments collected from deep slopes and basins (1018–4087 m depth) of the oligotrophic E... more Surface sediments collected from deep slopes and basins (1018–4087 m depth) of the oligotrophic Eastern Mediterranean Sea have been analysed for bulk elemental and isotopic composition of organic carbon, total nitrogen and selected lipid biomarkers, jointly with grain size distribution and other geochemical proxies. The distribution and sources of sedimentary organic matter (OM) have been subsequently assessed and general environmental variables, such as water depth and currents, have been examined as causative factors of deep-sea sediment characteristics. Lithogenic and biogenic carbonates are the dominant sedimentary fractions, while both bulk and molecular organic tracers reflect a mixed contribution from autochthonous and allochthonous sources for the sedimentary OM, as indicated by relatively degraded marine OM, terrestrial plant waxes and anthropogenic OM including degraded petroleum by-products, respectively. Wide regional variations have been observed amongst the studied pro...
Hydroécologie Appliquée, 1992
ABSTRACT This study presents the first sub-decadal scale sea-surface temperature (SSTs) time-seri... more ABSTRACT This study presents the first sub-decadal scale sea-surface temperature (SSTs) time-series derived from alkenone paleothermometry, covering the last 2000-year ocean temperature history of the the Labrador Sea region. The records obtained from two sites off Newfoundland document SST variations in a climatically crucial component of the Western North Atlantic circulation system, the southernmost Labrador Current (LC). This boundary current is a major conduit of cold and ice loaded fresh waters originating from the Arctic, which has a major impact on climate in the entire North Atlantic region. Our results demonstrate a clear link between the LC strength and the Northern Annular Mode (NAM), supporting the idea of a more persistent +NAM system and stronger LC during the Medieval Climate Anomaly (MCA). They also suggest enhanced LC activity under future warming with major implications for global thermohaline circulation.
We conducted high-resolution studies of two box-cores collected 300 km apart in the central Peruv... more We conducted high-resolution studies of two box-cores collected 300 km apart in the central Peruvian margin at 300 m and at 184 m depth off Pisco and Callao, respectively. While the Callao site is located closer to the upper boundary of the Oxygen Minimum Zone (OMZ) and to episodical continental sources, the Pisco site is located in the center of
Earth and Planetary Science Letters, 2014
AGU Fall Meeting …, 2008
... Authors: Bouloubassi, I.; Sicre, M.; Ezat, U.; Gondry, G.; Jacob, J.; Azzoug, M. Affiliation:... more ... Authors: Bouloubassi, I.; Sicre, M.; Ezat, U.; Gondry, G.; Jacob, J.; Azzoug, M. Affiliation: AA(LOCEAN, CNRS/UPMC/IPSL, 4 place Jussieu, Paris, 75005, France ; ), AB(LSCE, CNRS/CEA/UVSQ/IPSL, Domaine du CNRS, Ave de la Terrasse Bat.12, Gif-sur-Yvette, 91198, ...
Science of The Total Environment, 1990
ABSTRACT
Quaternary Science Reviews, 2013
ABSTRACT The recent rapid decline in Arctic sea ice cover has increased the need to improve the a... more ABSTRACT The recent rapid decline in Arctic sea ice cover has increased the need to improve the accuracy of the sea ice component in climate models and to provide detailed long-term sea ice concentration records, which are only available via proxy data. Recently, the highly branched isoprenoid IP25, identified in marine sediments underlying seasonal sea ice, has emerged as a potential sea ice specific proxy for past sea ice cover. We tested the reliability of this biomarker as a sea ice proxy against observational sea ice data (sea ice concentrations from the global HadISST1 database) and against a more established sea ice proxy (sea ice diatom abundance in sediments) in the South-West (SW) Labrador Sea. Furthermore, our study location at the southern margin of Arctic sea ice drift provided a new environmental setting in which to further test the novel PIP25 index. Our two study sites are located North-East (NE) and South-East (SE) of Newfoundland where box cores covering the last ca 100-150 years were collected. IP25 concentrations are nearly an order of magnitude higher and sea ice diatoms more abundant in sediments from NE of Newfoundland, where sea ice prevails 2-4 months per year compared to the sediments SE of Newfoundland, where conditions are generally ice-free year round. The IP25 fluxes NE of Newfoundland agree well with multi-decadal North Atlantic Oscillation (NAO) trends in the study area, which in previous studies have been shown to affect the climatic and sea ice conditions in the region. When assessed against observational sea ice data, IP25 appears to be a more sensitive indicator of sea ice variability in this setting compared to sea ice diatoms and proved to be a robust and reliable proxy for reconstructing low-frequency variability in past sea ice concentrations. The PIP25 index results clearly differ from the observed sea ice data underlining that caution needs to be exercised when using the index in different environmental settings.
Progress in Oceanography, 2011
Palaeogeography, Palaeoclimatology, Palaeoecology, 2014
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Papers by Ioanna Bouloubassi