Pascale Lherminier

Institut Français de Recherche pour l'Exploitation de la Mer | Ifremer · Department of Oceanography and Ecosystem Dynamics

The horizontal circulation of the subpolar gyre and the Meridional Overturning Circulation (MOC) are investigated here by comparing two snapshots of the North Atlantic as delivered by two hydrographic sections between Greenland and Portugal. The corresponding cruises were carried out in June–July 2002 and June–July 2004 on R/V Thalassa within the f...

To understand isobaric float measurements of vertical velocity during oceanic deep convective events, we compare experimental results obtained in the Greenland Sea with time series from an ensemble of modeled isobaric drifters embedded in a Large Eddy Simulation (LES), carried out with realistic initial conditions and time-dependent surface forcing...

The circulation and related transports at the south east tip of Greenland are determined from direct current observations from a moored current meter array. The measurements covered a time span from June 2004 to June 2006. From these measurements the net mean total southwestward transport from the mid-shelf (20 km off the coast at 60oN) to the 2070...

The decadal mean circulation in the northern North Atlantic was assessed for the early 21st century from repeated ship-based measurements along the Greenland-Portugal OVIDE line, from satellite altimetry and from earlier reported transports across 59.5°N and at the Greenland-Scotland sills. The remarkable quantitative agreement between all data set...

This study proposes new insights for the interpretation of GEOVIDE particle measurements. Potential resuspension sites due to internal tides (ITs) have been identified along the western Iberian shelf slope using a tidal regional model. Iberian shelf is mainly a source of lithogenic material whereas Galicia Bank is a source of biogenic matter. The p...

The characteristics of the CISE-LOCEAN seawater isotope dataset (δ18O, δ2H, referred to as δD) are presented (https://doi.org/10.17882/71186; Waterisotopes-CISE-LOCEAN, 2021). This dataset covers the time period from 1998 to 2021 and currently includes close to 8000 data entries, all with δ18O, three-quarters of them also with δD, associated with a...

Plain Language Summary The North Atlantic Deep Water is one of the most voluminous water masses of the global ocean. Its deepest constituent—the Lower North Atlantic Deep Water (LNADW)—forms in the Nordic Seas before cascading into the North Atlantic at the Greenland‐Iceland‐Scotland sills and progressing south toward the Southern Ocean. The temper...

Iceland-Scotland Overflow Water (ISOW) and Labrador Seawater (LSW) are major water masses of the lower Atlantic Meridional Overturning Circulation (AMOC). Therefore, the investigation of their transport pathways is important to understand the structure of the AMOC and how climate properties are exported from the North Atlantic to lower latitudes. T...

The characteristics of the CISE-LOCEAN sea water isotope data set (δ18O, δ2H, later designed as δD) are presented. This data set covers the time period from 1998 to 2021 and currently includes close to 8000 data entries, all with δ18O, three quarters of them also with δD, associated with a time and space stamp and usually a salinity measurement. Un...

In May 2018, an unprecedented long and intense seismic-volcanic crisis broke out off the island ofMayotte (Indian Ocean) and was associated with the birth of an underwater volcano. Since then, anintegrated observation network has been created (REVOSIMA), with the given objective of monitoringand better understanding underwater volcanic phenomena. R...

The North Atlantic Basin is a major sink for atmospheric carbon dioxide (CO2) due in part to the extensive plankton blooms which form there supported by nutrients supplied by the three-dimensional ocean circulation. Hence, changes in ocean circulation and/or stratification may influence primary production and biological carbon export. In this study...

Changes in the Atlantic Meridional Overturning Circulation, which have the potential to drive societally-important climate impacts, have traditionally been linked to the strength of deep water formation in the subpolar North Atlantic. Yet there is neither clear observational evidence nor agreement among models about how changes in deep water format...

Internal waves in the semi-diurnal and near-inertial bands are investigated using an array of seven moorings located over the Reykjanes Ridge in a cross-ridge direction (57.6-59.1 N, 28.5-33.3 W). Continuous measurements of horizontal velocity and temperature for more than two years allow us to estimate the kinetic energy density and the energy flu...

In the North Atlantic, there are two main western boundary currents related to the Atlantic Meridional Overturning Circulation (AMOC): the Gulf Stream flowing northward and the Deep Western Boundary Current (DWBC) flowing southward. Here we analyze data from the OVIDE section (GO-SHIP A25 Portugal-Greenland 40–60°N) that crosses the DWBC and the no...

Particulate concentrations of the 14 Rare Earth Elements (PREE), yttrium, and 232-thorium were measured in 200 samples collected in the epipelagic (ca. 0–200 m) and mesopelagic (ca. 200–1500 m) zones of the North Atlantic during the GEOVIDE cruise (May/June 2014, R/V Pourquoi Pas?, GEOTRACES GA01), providing the most detailed snapshot of the PREE d...

The oceanic uptake of atmospheric carbon dioxide (CO2) emitted by human activities alters the seawater carbonate system. Here, the chemical status of the Northeast Atlantic is examined by means of a high-quality database of carbon variables based on the GO-SHIP A25 section (1997-2018). The increase of atmospheric CO2 leads to an increase in ocean a...

The Atlantic Meridional Overturning Circulation (AMOC) is a key mechanism of heat, freshwater, and carbon redistribution in the climate system. The precept that the AMOC has changed abruptly in the past, notably during and at the end of the last ice age, and that it is ‘very likely’ to weaken in the coming century due to anthropogenic climate chang...

Dissolved Fe (DFe) samples from the GEOVIDE voyage (GEOTRACES GA01, May–June 2014) in the North Atlantic Ocean were analyzed using a seaFAST-pico™ coupled to an Element XR sector field inductively coupled plasma mass spectrometer (SF-ICP-MS) and provided interesting insights into the Fe sources in this area. Overall, DFe concentrations ranged from...

Particulate concentrations of the fourteen Rare Earth Elements (PREE), yttrium and 232-thorium have been measured in two hundred samples collected in the epipelagic (ca. 0–200 m) and the mesopelagic (ca. 200–1000 m) zones of the North Atlantic, during the GEOVIDE cruise (May/June 2014, R/V Pourquoi Pas ?, GEOTRACES GA01). Particulate cerium (PCe) c...

We investigate the origin of fresh water on the shelves near Cape Farewell (south Greenland) using sections of three hydrographic cruises in May (HUD2014007) and June 2014 (JR302 and Geovide). We partition the fresh water between meteoric water sources and sea ice melt or brine formation using the δ¹⁸O of sea water. The sections illustrate the pres...

The aim of the GEOVIDE cruise (May–June 2014, R/V Pourquoi Pas?) was to provide a better understanding of trace metal biogeochemical cycles in the North Atlantic Ocean. As marine particles play a key role in the global biogeochemical cycle of trace elements in the ocean, we discuss the distribution of particulate iron (PFe), in relation to the dist...

The GEOVIDE cruise, a collaborative project within the framework of the international GEOTRACES programme, was conducted along the French-led section in the North Atlantic Ocean (Section GA01), between 15 May and 30 June 2014. In this special issue (https://www.biogeosciences.net/special_issue900.html), results from GEOVIDE, including physical ocea...

Pathways and timescales of water mass transport in the subpolar North Atlantic Ocean (SPNA) have been investigated by many studies due to their importance for the meridional overturning circulation and thus for the global ocean. In this sense, observational data on geochemical tracers provide complementary information to improve the current underst...

The distribution of dissolved aluminium (dAl) in the water column of the North Atlantic and Labrador Sea was studied along GEOTRACES section GA01 to unravel the sources and sinks of this element. Surface water dAl concentrations were low (median of 2.5nM) due to low aerosol deposition and removal by biogenic particles (i.e. phytoplankton cells). Ho...

The North Atlantic Ocean is a major sink region for atmospheric CO2 and contributes to the storage of anthropogenic carbon (Cant). While there is general agreement that the intensity of the meridional overturning circulation (MOC) modulates uptake, transport and storage of Cant in the North Atlantic Subpolar Ocean, processes controlling their recen...

The GEOVIDE cruise, a collaborative project within the framework of the international GEOTRACES programme, was conducted along the French-led section in the North Atlantic Ocean (Section GA01), between 15 May and 30 June 2014. In this Special Issue, results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are pr...

The GEOTRACES Intermediate Data Product 2017 (IDP2017) is the second publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2016. The IDP2017 includes data from the Atlantic, Pacific, Arctic, Southern and Indian oceans, with about twice the data volume of the pre...

The GEOTRACES Intermediate Data Product 2017 (IDP2017) is the second publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2016. The IDP2017 includes data from the Atlantic, Pacific, Arctic, Southern and Indian oceans, with about twice the data volume of the pre...

The GEOVIDE cruise (May–June 2014, R/V Pourquoi Pas?) aimed to provide a better understanding on trace metal biogeochemical cycles in the North Atlantic. As particles play a key role in the global biogeochemical cycle of trace elements in the ocean, we discuss the distribution of particulate iron (PFe), in light of particulate aluminium (PAl), mang...

The distribution of ¹²⁹I and ²³⁶U in 14 depth profiles and the sea surface along the GEOVIDE section (transect GEOTRACES GA01) the subpolar North Atlantic (SPNA) is presented for spring 2014. This work investigates the use of ¹²⁹I and ²³⁶U as circulation tracers of water masses involved in the North Atlantic Meridional Overturning Circulation. The...

We report here the results of total mercury (HgT) determinations along the 2014 Geotraces Geovide cruise (GA01 transect) in the North Atlantic Ocean (NA) from Lisbon (Portugal) to the coast of Labrador (Canada). HgT concentrations in unfiltered samples (HgTUNF) were log-normally distributed and ranged between 0.16 and 1.54 pmol L−1, with a geometri...

We present the distribution of water masses along the GEOTRACES-GA01 section during the GEOVIDE cruise, which crossed the subpolar North Atlantic Ocean and the Labrador Sea in the summer of 2014. The water mass structure resulting from an extended optimum multiparameter (eOMP) analysis provides the framework for interpreting the observed distributi...

Dissolved Fe (DFe) samples from the GEOVIDE voyage (GEOTRACES GA01, May–June 2014) in the North Atlantic Ocean were analysed using a SeaFAST-picoTM coupled to an Element XR HR-ICP-MS and provided interesting insights on the Fe sources in this area. Overall, DFe concentrations ranged from 0.09 ± 0.01 nmol L−1 to 7.8 ± 0.5 nmol L−1. Elevated DFe conc...

Since the Industrial Revolution, the North Atlantic Ocean has been accumulating anthropogenic carbon dioxide (CO2) and experiencing ocean acidification, that is, an increase in the concentration of hydrogen ions (a reduction in pH) and a reduction in the concentration of carbonate ions. The latter causes the 'aragonite saturation horizon'-below whi...

The distribution of dissolved aluminium (dAl) in the water column of the North Atlantic and Labrador Sea was studied along GEOTRACES section GA01 to unravel the sources and sinks of this element. Surface water dAl concentrations were low (median of 2.5 nM) due to low aerosol deposition and removal by phytoplankton. However, surface water dAl concen...

The GEOVIDE cruise was carried out in the subpolar North Atlantic (SPNA) along the OVIDE section and across the Labrador Sea in May–June 2014. It was planned to clarify the distribution of the trace elements and their isotopes in the SPNA as part of the GEOTRACES international program. This paper focuses on the state of the circulation and distribu...

The Labrador Sea links the Arctic and North Atlantic oceans and constitutes one of the main entrances of atmospheric inputs into the Ocean's interior. We report here the first high-resolution Hg distribution pattern along a transect from Greenland to Labrador coasts sampled after the 2014 winter convection. Total Hg concentrations in unfiltered (Hg...

We report here the results of total mercury (HgT) determinations along the 2014 GEOTRACES GEOVIDE cruise (GA01 transect) in the North Atlantic Ocean (NA) from Lisbon (Portugal) to the Labrador coast (Canada). Ninety-seven percent of the HgT concentrations of unfiltered samples (HgTUNF) ranged between 0.16 and 1.00 pmol L−1. The geometric mean was 0...

We present the distribution of water masses along the GEOTRACES-GA01 section during the GEOVIDE cruise, which crossed the subpolar North Atlantic Ocean and the Labrador Sea in the summer of 2014. The water mass structure resulting from an extended Optimum MultiParameter (eOMP) analysis provides the framework for interpreting the observed distributi...

We analyzed several natural radionuclides in both the dissolved and particulate phases collected along the GA01 section conducted in the North Atlantic (May-July 2014; Portugal-Greenland-Canada; GEOVIDE project) in the framework of the international GEOTRACES program. In this work, we studied the distribution of radium-226 (226 Ra, t1/2=1602 y) tha...

The GEOVIDE cruise was carried out in the subpolar North Atlantic (SPNA), along the OVIDE section and across the Labrador Sea, in May–June 2014. It was planned to clarify the distribution of the trace elements and their isotopes in the SPNA as part of the GEOTRACES international program. This paper focuses on the state of the circulation and distri...

The Labrador Current is an important conduit of freshwater from the Arctic to the interior North Atlantic subpolar gyre. Here we investigate the spatial variability of the freshwater sources over the southern Labrador shelf and slope during May?June 2014. Using measurements of seawater properties such as temperature, salinity, nutrients, and oxygen...

The North Atlantic Ocean is a major sink region for anthropogenic carbon (Cant) and a major contributor to its storage. While it is in general agreed that the intensity of the meridional overturning circulation (MOC) modulates uptake, transport and storage of Cant in the North Atlantic Subpolar Ocean, processes controlling their recent variability...

We investigate whether one can detect changes in the freshwater contributions to the North Atlantic subpolar gyre (SPG), in light of the observed recent decrease of salinity in the region. We focus on two important conduits of freshwater from the Arctic to the interior North Atlantic subpolar gyre: the Coastal Labrador Current and the southern Gree...

The variability of the turbulent kinetic energy dissipation due to internal waves is quantified using a finescale parameterization applied to the A25 Greenland-Portugal transect repeated every two years from 2002 to 2012. The internal wave velocity shear and strain are estimated for each cruise at 91 stations from full depth vertical profiles of de...

The subpolar North Atlantic (SPNA) is important in the global carbon cycle because of the deep water ventilation processes that lead to both high uptake of atmospheric CO2 and large inventories of anthropogenic CO2 (Cant). Thus, it is crucial to understand its response to increasing anthropogenic pressures. In this work, the budgets of dissolved in...

We will present results of the recent French-led GEOTRACES cruise GEOVIDE in the North Atlantic Ocean. Research vessel “Pourquoi pas?” sailed on 15. May from Lisbon to Greenland to arrive in Newfoundland on 30. June 2014. Total mercury was sampled using an ultra-trace clean rosette and determined on board in a class100 clean container following the...

We discuss the distributions and transports of the main water masses in the North Atlantic Subpolar Gyre (NASPG) for the mean of the period 2002–2010 (OVIDE sections 2002 to 2010 every other year), as well as the inter-annual variability of the water mass structure from 1997 (4x and METEOR sections) to 2010. The water mass structure of the NASPG, q...

http://cdiac.ornl.gov/ftp/oceans/CLIVAR/OVIDE_2012/. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, US Department of Energy, Oak Ridge, Tennessee