Fatima F Abrantes

Fatima F Abrantes
Instituto Português do Mar e da Atmosfera | IPMA · Marine Geology

PhD in Geological Oceanography

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251
Publications
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Publications

Publications (251)
Technical Report
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International Ocean Discovery Program (IODP) Expedition 397 will take place off the Iberia Peninsula where rapidly accumulating sediments contain a high-fidelity record of past climate change. Most sediment in the deep sea accumulates at rates of 1–2 cm every thousand years, whereas sediments in the targeted area accumulate ten times faster (10–20...
Article
Long-chain unsaturated alkenones produced by haptophyte algae are widely used as paleotemperature indicators. The unsaturation relationship to temperature is linear at mid-latitudes, however, non-linear responses detected in subpolar regions of both hemispheres have suggested complicating factors in these environments. To assess the influence of bi...
Article
Full-text available
Marine microcharcoal records provide invaluable information to understand changes in biomass burning and its drivers over multiple glacial and interglacial cycles and to evaluate fire models under warmer climates than today. However, quantitative reconstructions of burnt area, fire intensity and frequency from these records need calibration studies...
Article
Full-text available
Physical and biogeochemical processes in the Southern Ocean are fundamental for modulating global climate. In this context, a process-based understanding of how Antarctic diatoms control primary production and carbon export, and hence global-ocean carbon sequestration, has been identified as a scientific priority. Here we use novel sediment trap ob...
Article
Marine Isotope Stage (MIS) 13,~533e478 ka, has received particular attention due to the unexpected enhancement of monsoon systems under a cool climate characterized by lower atmospheric CO 2 and larger ice volume than many other interglacials. Key questions remain about its regional expression (intensity, climate variability, length), and underlyin...
Article
O vulcão de lama serpentinizada Yinazao, localizado no antepaís das Marianas, foi amostrado durante a Expedição 366 do Programa IODP. Verificou-se a ocorrência de aragonite e calcite, predominantemente nos primeiros metros da coluna sedimentar, onde a oxidação e a circulação de água do mar mais se fazem sentir. Os resultados deste trabalho demonstr...
Article
The Sines Contourite Drift (SCD), located in the Alentejo margin, southwest Iberian continental margin, has been through many depositional phases in result of climatic variations and bottom current oscillations, which determined a variable depositional pattern and an irregular sedimentary evolution since the Late Pleistocene. The SCD, being in the...
Article
Full-text available
The Southern Ocean is warming faster than the average global ocean and is particularly vulnerable to ocean acidification due to its low temperatures and moderate alkalinity. Coccolithophores are the most productive calcifying phytoplankton and an important component of Southern Ocean ecosystems. Laboratory observations on the most abundant coccolit...
Article
Full-text available
Ocean acidification is expected to have detrimental consequences for the most abundant calcifying phytoplankton species Emiliania huxleyi. However, this assumption is mainly based on laboratory manipulations that are unable to reproduce the complexity of natural ecosystems. Here, E. huxleyi coccolith assemblages collected over a year by an autonomo...
Article
Full-text available
Planktonic foraminifera δ18O and Mg/Ca ratios are widely considered as a powerful proxy to reconstruct past seawater‐column temperature. Due to the complex interpretation of planktonic foraminifera δ18O data in regard to past seawater temperatures, temperature determination based on the foraminifera shell Mg/Ca ratio is believed to be more accurate...
Article
Full-text available
Southern Ocean waters are projected to undergo profound changes in their physical and chemical properties in the coming decades. Coccolithophore blooms in the Southern Ocean are thought to account for a major fraction of the global marine calcium carbonate (CaCO3) production and export to the deep sea. Therefore, changes in the composition and abun...
Article
Full-text available
Proboscia barboi and Proboscia curvirostris are two important diatom biostratigraphic markers from the high latitudes of the North Pacific and North Atlantic Oceans, dating back to the Pliocene-Pleistocene time. This study analyzes the biostratigraphic events and describes the morphology of P. barboi and P. curvirostris, particularly the morphologi...
Article
p>The South Asian Monsoon (SAM) drives seasonal changes in the atmospheric and ocean circulation of the tropical Indian Ocean, affecting precipitation on land and oceanic primary productivity. This work examined sediments from the International Ocean Discover Program (IODP) Site U1467 (IODP Expedition 359) located in the Maldives Inner Sea (Norther...
Poster
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The aims of the present work are to understand the Yinazao features which provide authigenic carbonate precipitation and infer the major Carbon source in this system. We also propose a formation model of Yinazao authigenic carbonates by comparing them to authigenic carbonates from sedimentary mud volcanoes and pockmarks of the Gulf of Cadiz (GOC).
Article
Full-text available
Southern Ocean waters are projected to undergo profound changes in their physical and chemical properties in the coming decades. Coccolithophore blooms in the Southern Ocean are thought to account for a major fraction of the global marine calcium carbonate (CaCO3) production and export to the deep sea. Therefore, changes in the composition and abun...
Article
Full-text available
The ocean is the most important subsystem of the Earth’s climate system and functions as its heart, regulating the energy distribution of the planet [...]
Preprint
Paleoclimate reconstructions suggest that the complex variability within the Greenland stadial 1 (GS-1) over western Europe was governed by coupled ocean and atmospheric changes. However, few works from the North Atlantic mid-latitudes document both the GS-1 onset and its termination, which are often considered as single abrupt transition events. H...
Article
Full-text available
The southwestern Iberian margin is highly sensitive to changes in the distribution of North Atlantic currents and to the position of oceanic fronts. In this work, the evolution of oceanographic parameters from 812 to 530ka (MIS20–MIS14) is studied based on the analysis of planktonic foraminifer assemblages from site IODP-U1385 (37°34.285′N, 10°7.56...
Article
Full-text available
The suitability of MIS 11c and MIS 19c as analogues of our present interglacial and its natural evolution is still debated. Here we examine the regional expression of the Holocene and its orbital analogues over SW Iberia using a model–data comparison approach. Regional tree fraction and climate based on snapshot and transient experiments using the...
Article
The Antarctic Zone, the southernmost belt of the Antarctic Circumpolar Current, plays an important role in the control of atmospheric carbon dioxide concentrations. In the last decade, a number of studies have highlighted the importance of diatom assemblage composition in influencing the magnitude of the organic carbon and biogenic silica fluxes ex...
Article
Full-text available
The southwestern Iberian margin is highly sensitive to changes in the distribution of North Atlantic currents, and to the position of oceanic fronts. In this work, the evolution of oceanographic parameters from 812 to 530 ka (MIS20-MIS14) is reconstructed, based on the analysis of planktonic foraminifer assemblages from site IODP-U1385 (37°34.285&a...
Article
Full-text available
A systematic investigation of the spatial and temporal variability in coccolithophore abundance and distribution through the water column of the NW Iberian coastal upwelling system was performed. From July 2011 to June 2012, monthly sampling at various water depths was conducted at two parallel stations located at 42� N. Total coccosphere abundance...
Article
Full-text available
The Mediterranean region is a climate hot spot, sensitive not only to global warming but also to water availability. In this work we document major temperature and precipitation changes in the Iberian Peninsula and margin during the last 2000 years and propose an interplay of the North Atlantic internal variability with the three atmospheric circul...
Article
The Iberian Margin is a sensitive area to track high and low latitude processes, and is a key location to understand major past climatic and oceanographic changes. Here we present new biomarker data from IODP Site U1385 (“Shackleton site”) (1017–336 ka) that, when combined with existing data from Cores MD01-2443/4 (last 335 ka), allows us to assess...
Article
Coral mounds formed by framework-forming scleractinian cold-water corals (CWC; mainly Lophelia pertusa) are a common seabed feature along the Atlantic continental margins. While coral mound areas in the NE Atlantic reveal a climate-dependent temporal pattern of CWC occurrence and mound aggradation that is related to distinct environmental condition...
Article
The Mid-Pleistocene transition and the response of sea ice in the subarctic North Pacific are examined using a diatom record from the north eastern Bering Sea slope (IODP core U1344A). High percentages of diatom sea ice species in the assemblage foster the development of groupings specific to differing ice conditions. Thalassiosira antarctica var....
Article
Marine Isotope Stage 31 (MIS 31) is an important analogue for ongoing and projected global warming, yet key questions remain about the regional signature of its extreme orbital forcing and intra-interglacial variability. Based on a new direct land-sea comparison in SW Iberian margin IODP Site U1385 we examine the climatic variability between 1100 a...
Article
Full-text available
The objective of the current work is to improve our understanding of how water column diatom's abundance and assemblage composition is seasonally transferred from the photic zone to seafloor sediments. To address this, we used a dataset derived from water column, sediment trap and surface sediment samples recovered in the NW Iberian coastal upwelli...
Article
Full-text available
Climatic variability of Marine Isotope Stage (MIS) 11 is examined using a new high-resolution direct land–sea comparison from the SW Iberian margin Site U1385. This study, based on pollen and biomarker analyses, documents regional vegetation, terrestrial climate and sea surface temperature (SST) variability. Suborbital climate variability is reveal...
Article
Full-text available
Coastal upwelling systems account for approxi- mately half of global ocean primary production and contribute disproportionately to biologically driven carbon se- questration. Diatoms, silica-precipitating microalgae, consti- tute the dominant phytoplankton in these productive regions, and their abundance and assemblage composition in the sed- iment...
Article
Full-text available
TThe objective of the current work is to improve our understanding of how water column diatom's abundance and assemblage composition is seasonally transferred from the photic zone to seafloor sediments. To address this, we used a dataset derived from water column, sediment trap and surface sediment samples recovered in the NW Iberian coastal upwell...
Article
To better understand sources and transport of particulate material in the NW Iberian coastal upwelling system, a mooring line dotted with an automated PPS 4/3 sediment trap was deployed off Cape Silleiro at the base of the photic zone. The samples were collected from November 2008 through June 2012 over sampling periods of 4–12 days. Our study repr...
Article
Full-text available
Coastal upwelling systems account for approximately half of global ocean primary production and contribute disproportionately to biologically driven carbon sequestration. Diatoms, silica–precipitating microalgae, constitute the dominant phytoplankton in these productive regions, and their abundance and assemblage composition in the sedimentary reco...
Article
We present the first multi-site study of dinoflagellate cyst records spanning ca. AD 1860–2000 from the west Iberian coast. Our aim was to reconstruct environmental changes in the Western Iberia Upwelling Ecosystem, one of the most biologically productive areas in the world, and an active fishery region. A major shift in cyst assemblages was record...
Data
Coastal upwelling systems account for approximately half of global ocean primary production and contribute disproportionately to biologically driven carbon sequestration. Diatoms, silica-precipitating microalgae, constitute the dominant phytoplankton in these productive regions, and their abundance and assemblage composition in the sedimentary reco...
Data
The distribution and microhabitat of living benthic fora- minifera (15 calcareous and 6 agglutinated) have been studied in two box cores from the Tagus Prodelta. Stable oxygen and carbon isotopes were analysed for eight different species from six surface samples from the Tagus Prodelta and Estuary. At the two box core stations, most of the living f...
Article
Climatic and oceanographic changes, as occurring at a glacial–interglacial scale, may alter the environmental conditions needed for the development of prolific cold-water coral reefs and mounds. Studies constraining the temporal distribution of cold-water corals in the NE Atlantic suggested the cyclic changes of the Atlantic Meridional Overturning...
Article
Climatic and oceanographic changes, as occurring at a glacial–interglacial scale, may alter the environmental conditions needed for the development of prolific cold-water coral reefs and mounds. Studies constraining the temporal distribution of cold-water corals in the NE Atlantic suggested the cyclic changes of the Atlantic Meridional Overturning...
Article
The direct comparison between marine and terrestrial data from the NW Iberian margin, core MD03-2697, allows us to accurately evaluate, without chronological ambiguity, the vegetation response to North Atlantic climate events across the last deglaciation. Comparison of MD03-2697 data with other marine and terrestrial records from a vast area stretc...
Article
Twenty century time-resolved variability of riverine deposits of polychlorobiphenyls (PCBs), DDTs, hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) was studied in three (210)Pb dated sediment cores collected in a depositional shelf area adjacent to the Tagus estuary (the Tagus Prodelta). The geographic and temporal distribution patterns we...
Article
Full-text available
We produced a composite depth scale and chronology for Site U1385 on the SW Iberian Margin. Using log(Ca/Ti) measured by core scanning XRF at 1-cm resolution in all holes, a composite section was constructed to 166.5 meter composite depth (mcd) that corrects for stretching and squeezing in each core. Oxygen isotopes of benthic foraminifera were cor...
Article
A high-resolution sedimentary sequence recovered from the Tagus prodelta has been studied with the objective to reconstruct multi-decadal to centennial-scale climate variability on the western Iberian Margin and to discuss the observations in a wider oceanographic and climatic context. Between ca. 100 BC and AD 400 the foraminiferal fauna and high...
Data
A high-resolution diatom census coupled with other proxy data from Laurentian Fan (LF) provides a detailed description of the last deglaciation, bringing new insight to that period by revealing directly the timing of sea-ice formation and melting. Cold events Heinrich Event 1 (H1) and the Younger Dryas (YD) were multiphase events. H1 (~16.8-15.7 ca...
Data
A high-resolution sedimentary sequence recovered from the Tagus prodelta has been studied with the objective to reconstruct multi-decadal to centennial-scale climate variability on the western Iberian Margin and to discuss the observations in a wider oceanographic and climatic context. Between ca. 100 BC and AD 400 the foraminiferal fauna and high...
Article
Full-text available
The existence of a wide bed of the crinoid Leptometra celtica (M'Andrew and Barrett 1857), at approx-imately 500 m depth, off the Portuguese south coast is inferred from remotely operated vehicle (ROV) transects carried out as part of a research project (IMPACT) aimed at evaluating the impact of bottom trawling on the burrowing crustacean Norway lo...
Article
The existence of a wide bed of the crinoid Leptometra celtica (M’Andrew and Barrett 1857), at approximately 500 m depth, off the Portuguese south coast is inferred from remotely operated vehicle (ROV) transects carried out as part of a research project (IMPACT) aimed at evaluating the impact of bottom trawling on the burrowing crustacean Norway lob...
Article
Comparison between an archive dataset, collected during the 1970s (1974-1977), and samples taken during the PALEO1 cruise (2002) enabled evaluation of large-scale and long-term spatiotemporal changes in Al, Cr, Ni, Pb and Zn contents in bulk surface sediments in four areas of the Portuguese shelf. The so-called gradient method (GM) with normalisati...
Data
Fifteen Iberian margin sediment cores, distributed between 43°12'N and 35°53'N, have been used to reconstruct spatial and temporal (sub)surface circulation along the Iberian margin since the Last Glacial period. Time-slice maps of planktonic foraminiferal derived summer sea surface temperature (SST) and export productivity (Pexp) were established f...
Article
Full-text available
Nick Shackleton’s research on piston cores from the Iberian margin highlighted the importance of this region for providing high-fidelity records of millennial-scale climate variability, and for correlating climate events from the marine environment to polar ice cores and European terrestrial sequences. During the Integrated Ocean Drilling Program (...
Conference Paper
The direct correlation between terrestrial (pollen) and marine (planktonic δ18O) proxies from a slope core (KNR 178-2 JPC 32), retrieved in the Cape Hatteras (35°58.58'N, 74°42.77'W, 1006 m), provide substantial information on the Eastern North American vegetation response to the Holocene climate and oceanographic changes of the western North Atlan...