Isabelle M. Gil

Instituto Português do Mar e da Atmosfera | IPMA · Divisão de Geologia e Georecursos Marinhos

Millennial scale events marked by the contribution of detrital sand are recorded in North Atlantic sediments during the Last Glacial Maximum (LGM), between Heinrich events (HE) 1 and 2, and left their imprint on Laurentian Fan (LF – 43°N) sediments off eastern Canada. The LF counterpart of the well-known detrital events consist of glacial red-brick...

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...

Diatoms are unicellular photosynthetic organisms (algae) that synthesize an opaline silica cell wall comprised of two separate valves/frustules that are potentially preservable.Diatoms live wherever there is water, in marine and terrestrial environments. In the world's oceans, these primary producers constitute the base of the food chain and are ab...

High-resolution diatom species counts describe major deglacial and Holocene oceanographic changes over the Laurentian Fan. Diatoms provide direct evidences for temperature and salinity changes and attest the presence of ice. No diatom paleoceanographic reconstruction is available for this location yet, although the parameters they trace are known t...

Heinrich event 1 (H1) is a climate event resulting from the release into the North Atlantic of a huge volume of sea ice and icebergs from the northern hemisphere ice sheets. We present here high-resolution diatom records from the Bermuda Rise (Sargasso Sea) and the Laurentian Fan (South of Newfoundland) to assess its impacts on North Atlantic surfa...

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 24 (2009): PA4101, doi:10.1029/2008PA001729. Diatom assemblages document surface hydrographic changes over the Bermuda Rise. Be...

High-resolution proxy data analyzed on two high-sedimentation shallow water sedimentary sequences (PO287-26B and PO287-28B) recovered off Lisbon (Portugal) provide the means for comparison to long-term instrumental time series of marine and atmospheric parameters (sea surface temperature (SST), precipitation, total river flow, and upwelling intensi...

High-resolution proxy data analyzed on two high-sedimentation shallow water sedimentary sequences (PO287-26B and PO287-28B) recovered off Lisbon (Portugal) provide the means for comparison to long-term instrumental time series of marine and atmospheric parameters (sea surface temperature (SST), precipitation, total river flow, and upwelling intensi...

Diatom assemblages document the surface hydrographic changes over the Bermuda Rise between 19.2 and 14.5 ka BP. Subtropical warm water diatom species and Chaetoceros resting spores dominate the assemblages, as would be expected from more productive regions in the North Atlantic. Beginning 16.9 ka BP and lasting until 14.6 ka BP, brackish diatoms ar...

High-resolution diatom and phytolith quantitative and assemblage analyses have been conducted on two box-cores from the Tagus pro-delta (SW Portuguese Margin) in order to compare these common palaeoceanographic proxies to instrumental data describing the upwelling regime and the freshwater input of the Tagus River. The western Portuguese margin is...

We present a high-resolution palaeoenvironmental reconstruction covering the late Holocene from the Skagerrak and other sites in the North Sea area. The data, which are based on the analyses of marine sediment cores, reveal a marked environmental shift that took place between AD 700 and AD 1100, with the most pronounced changes occurring at AD 900....

The Tagus Prodelta (W Portugal) and the Muros Ría (NW Spain) are areas of high deposition rates registering high-resolution palaeoclimatic records for western Iberia. We compare the climatic conditions of the two areas over the last two millennia based on proxies of temperature (sea surface temperatures and oxygen isotopes), continental input (grai...

The Tagus pro-delta (Portuguese Margin) and the Skagerrak (NE of the North Sea) are two marine systems controlled by atmospheric changes, which at present are mainly determined by fluctuations of the North Atlantic Oscillation (NAO). On the basis of diatom records from marine sediment cores, environmental changes (primary productivity and salinity)...

Several locations along the North Atlantic margins are investigated to provide high-resolution paleoceanographic reconstructions based on diatom records for the last 2000 yrs: the Tagus pro-delta (SW Portuguese margin), the Skagerrak (NE North Sea) and the Laurentian fan (South of Newfoundland). The North Atlantic Oscillation (NAO) is considered as...

Sea Surface Temperature (SST), river discharge and biological productivity have been reconstructed from a multi-proxy study of a high-temporal-resolution sedimentary sequence recovered from the Tagus deposition center off Lisbon (Portugal) for the last 2000 years. SST shows 2 °C variability on a century scale that allows the identification of the M...

From west to east, the Fluminense coastline, composed of two series of lagoons, presents an aridity gradient induced by a local upwelling that is controlled by trade winds coming from the south Atlantic. The physico-chemical conditions of the lagoons are controlled by the duration of the dry season. They are characterized by hypersaline conditions...

Laboratory techniques employed for cleaning marine sediments for quantitative diatom analyses are time consuming and expensive. In an attempt to reduce preparation time, the method in use in our laboratory, has been compared to six other different methods, which derive from Barron's procedure for rapid sample preparation at sea.Based on the statist...

Sea Surface Temperature (SST), river discharge and biological productivity have been reconstructed from a multi-proxy study of a high-temporal-resolution sedimentary sequence recovered from the Tagus deposition center off Lisbon (Portugal) for the last 2000 years. SST shows 2 °C variability on a century scale that allows the identification of the M...

This work is part of the EU-HOLSMEER project which aim is to assess climatic variability, through the study of high sedimentary sequences from shallow environments of Europe for the last 2000 years. The Tagus pro-delta (38ºN, D13902-Portuguese margin) and the Skagerrak (58ºN, GeoB6003-2-NE North Sea) are characterized by sedimentation rates in the...

The North Atlantic Oscillation (NAO) is known to have a major influence on the wintertime climate of the Atlantic basin and surrounding countries, determining precipitation and wind conditions at mid-latitudes. A comparison of Hurrel’s NAO index to the mean winter (January-March) discharge of the Iberian Tagus River reveals a good negative correlat...