Fabien Roquet

Fabien Roquet
University of Gothenburg | GU · Department of Marine Sciences

Professor
Use Animal borne ocean sensors, observe the Southern Ocean, study the global overturning circulation

About

101
Publications
30,736
Reads
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3,397
Citations
Introduction
I am a physical oceanographer interested in the observation and study of the global ocean circulation, with a specific focus on the Southern Ocean circulation. My main research interests : 1) Southern Ocean circulation 2) Observation with instrumented marine animals (MEOP) 3) Ocean modelling (NEMO, ECCO) 4) Ocean energetics and thermodynamics (TEOS-10)
Additional affiliations
August 2018 - present
University of Gothenburg
Position
  • Professor
February 2012 - July 2018
Stockholm University
Position
  • Research Associate
December 2009 - December 2011
Massachusetts Institute of Technology
Position
  • PostDoc Position
Education
September 2006 - December 2009
LOCEAN
Field of study
  • Physical Oceanography

Publications

Publications (101)
Article
Full-text available
Animal-Borne Ocean Sensors—AniBOS—is an emerging network of the Global Ocean Observing System (GOOS). AniBOS makes freely available oceanographic measurements across the hard-to-observe world's polar and tropical oceans from miniaturized sensors attached to marine animals. These data complement conventional approaches by providing both physical and...
Article
Southern Ocean bathymetry constrains the path of the Antarctic Circumpolar Current (ACC), but the bathymetric influence on the coupled ocean-atmosphere system is poorly understood. Here, we investigate this impact by respectively flattening large topographic barriers around the Kerguelen Plateau, Campbell Plateau, Mid-Atlantic Ridge, and Drake Pass...
Preprint
Full-text available
Despite the ever-growing amount of ocean’s data, the interior of the ocean remains under sampled in regions of high variability such as the Gulf Stream. In this context, neural networks have been shown to be effective for interpolating properties and understanding ocean processes. We introduce OSnet (Ocean Stratification network), a new ocean recon...
Article
Full-text available
We provide a detailed description of the spatial distribution, seasonality and transformation of the main water masses within MacKenzie Polynya (MP) in Prydz Bay, East Antarctica, using data from instrumented southern elephant seals. Dense Shelf Water (DSW) formation in MP shows large spatial variability that is related to the (i) local bathymetry,...
Article
Full-text available
Marine animals equipped with biological and physical electronic sensors have produced long-term data streams on key marine environmental variables, hydrography, animal behavior and ecology. These data are an essential component of the Global Ocean Observing System (GOOS). The Animal Borne Ocean Sensors (AniBOS) network aims to coordinate the long-t...
Article
Full-text available
The Southern Ocean is responsible for the majority of the global oceanic heat uptake that contributes to global sea level rise. At the same time, ocean temperatures do not change at the same rate in all regions and sea level variability is also affected by changes in salinity. This study investigates ten years of steric height variability (2008 to...
Article
Full-text available
Understanding the physical mechanisms behind the transport and accumulation of floating objects in the ocean is crucial to efficiently tackle the issue of marine pollution. The main sinks of marine plastic are the coast and the bottom sediment. This study focuses on the former, investigating the timescales of dispersal from the ocean surface and on...
Article
Full-text available
Rapid and regionally contrasting climate changes have been observed around Antarctica. However, our understanding of the impact of these changes on ecosystems remains limited, and there is an urgent need to better identify habitats of Antarctic species. The Weddell seal ( Leptonychotes weddellii ) is a circumpolar mesopredator and an indicative spe...
Preprint
Full-text available
The Southern Ocean is responsible for the majority of the global oceanic heat uptake that contributes to global sea level rise. At the same time, ocean temperatures do not change at the same rate in all regions and sea level variability is also affected by changes in salinity. This study investigates ten years of steric height variability (2008 to...
Article
Full-text available
Plain Language Summary When tidal ocean currents flow over bumpy seafloor, they generate internal tidal waves. Internal waves are the subsurface analog of surface waves that break on beaches. Like surface waves, internal tidal waves often become unstable and break into turbulence. This turbulence is a primary cause of mixing between stacked ocean l...
Article
Full-text available
The first 2000 m of the global thermohaline structure of the ocean are statistically decomposed into vertical thermohaline modes, using a multivariate Functional Principal Component Analysis (FPCA). This method is applied on the Monthly Isopycnal & Mixed-layer Ocean Climatology (MIMOC). The first three modes account for 92% of the joint temperature...
Article
Full-text available
Animal telemetry is a powerful tool for observing marine animals and the physical environments that they inhabit, from coastal and continental shelf ecosystems to polar seas and open oceans. Satellite-linked biologgers and networks of acoustic receivers allow animals to be reliably monitored over scales of tens of meters to thousands of kilometers,...
Article
Full-text available
Temperature and salinity measurements obtained from sensors deployed on Weddell seals (Leptonychotes weddellii) between late austral summer and the following spring for 2010–2012 were used to describe the temporal and spatial variability of hydrographic conditions in the western Ross Sea, with particular emphasis on the inner-shelf region off Victo...
Article
Full-text available
Internal tides power much of the observed small-scale turbulence in the ocean interior. To represent mixing induced by this turbulence in ocean climate models, the cascade of internal tide energy to dissipation scales must be understood and mapped. Here, we present a framework for estimating the geography of internal tide energy sinks. The mapping...
Article
Full-text available
Most available CTD–Satellite Relay Data Logger (CTD–SRDL) profiles are heavily compressed before satellite transmission. High-resolution profiles recorded at the sampling frequency of 0.5 Hz are however available upon physical retrieval of the logger. Between 2014 and 2018, several loggers deployed on elephant seals in the Southern Ocean have been...
Data
The dataset contains global estimates of barotropic-to-baroclinic tidal energy conversion at 1/30-degree resolution. Three types of estimates are available: 1. Non-modal conversion rates calculated by Falahat et al. (2014) following the method of Nycander (2005). A map for each of the eight most energetic tidal constituents (M2, S2, K1, O1, N2, K...
Data
The dataset consists of global two-dimensional maps of internal tide energy sources and sinks, at half-degree horizontal resolution. Estimated energy sources are provided for the three most energetic tidal constituents: M2, S2 and K1. They are decomposed into vertical normal modes. Units are Watts per square meter. Estimated energy sinks are prov...
Article
Full-text available
The location of the Antarctic Polar Front (PF) is mapped in the Southern Indian Ocean by decomposing the shape of temperature and salinity profiles into vertical modes using a functional Principal Component Analysis. We define the PF as the northernmost minimum of temperature at the subsurface, and represent it as a linear combination of the first...
Article
While the Atlantic Ocean is ventilated by high-latitude deep water formation and exhibits a pole-to-pole overturning circulation, the Pacific Ocean does not. This asymmetric global overturning pattern has persisted for the past 2–3 million years, with evidence for different ventilation modes in the deeper past. In the current climate, the Atlantic-...
Article
Full-text available
In the Amundsen Sea, warm saline Circumpolar Deep Water (CDW) crosses the con- tinental shelf toward the vulnerable West Antarctic ice shelves, contributing to their basal melting. Due to lack of observations, little is known about the spatial and temporal variability of CDW, particularly seasonally. A new dataset of 6704 seal-tag temperature and s...
Article
Full-text available
The effect of thermal mass on the salinity estimate from conductivity–temperature–depth (CTD) tags sensor mounted on marine mammals is documented, and a correction scheme is proposed to mitigate its impact. The algorithm developed here allows for a direct correction of the salinity data, rather than a correction of the sample’s conductivity and tem...
Article
Full-text available
Antarctic coastal polynyas are regions of persistent open water and are thought to be key bio-physical features within the sea-ice zone. However, their use by the upper trophic levels of ecosystems remains unclear. A unique bio-physical dataset recorded by southern elephant seals reveals that East Antarctic polynyas are a key winter foraging habita...
Article
Full-text available
High inputs of nutrients and organic matter make coastal seas places of intense air-sea CO2 exchange. Due to their complexity, the role of coastal seas in the global air-sea CO2 exchange is, however, still uncertain. Here we investigate the role of phytoplankton stoichiometric flexibility and extracellular DOC production for the seasonal nutrient a...
Data
This gridded product consists of a global (80°S-62°N) climatological estimate of radiocarbon content (∆14C) at half-degree horizontal resolution, provided both on neutral density and depth surfaces. It is based on the GLODAPv2 data compilation (Key et al. 2016, Olsen et al. 2016) and the neutral density (γn; Jackett and McDougall 1997) field of the...
Article
Full-text available
The abyssal ocean is broadly characterized by northward flow of the densest waters and southward flow of less-dense waters above them. Understanding what controls the strength and structure of these interhemispheric flows—referred to as the abyssal overturning circulation—is key to quantifying the ocean’s ability to store carbon and heat on timesca...
Article
Full-text available
The Stommel box model elegantly demonstrates that the oceanic response to mixed boundary conditions, combining a temperature relaxation with a fixed salt flux forcing, is non-linear owing to the so-called salt advection feedback. This non-linearity produces a parameter range of bi-stability associated with hysteresis effects characterised by a fast...
Poster
Full-text available
The Kerguelen Plateau obstructs the eastward flowing Antarctic Circumpolar Current (ACC) in the Indian sector of the Southern Ocean strongly interacting with the frontal structure. While the Subantarctic Front (SAF) lies north of the plateau and the Southern ACC Front (SACCF) is deflected southward by the Fawn Trough, the position and structure of...
Poster
Full-text available
Context: Although some associations between the leatherback turtle Dermochelys coriacea and the Gulf Stream current have been previously suggested, no study has to date demonstrated strong affinities between leatherback movements and this particular frontal system using thorough oceanographic data in both the horizontal and vertical dimensions. Obj...
Article
Full-text available
Ch 7. Regional Climates: f. Europe and the Middle East
Article
Full-text available
The Sea of Okhotsk is a challenging environment for obtaining in situ data and satellite observation in winter due to sea ice cover. In this study, we evaluated the validity of hydrographic observations by marine mammals (e.g., seals and sea lions) equipped with oceanographic conductivity-temperature-depth (CTD) sensors. During 4-yr operations from...
Article
Full-text available
“Biologging” through temporary attachment of miniaturized data loggers on marine animals is revolutionizing the science of marine ecology (Block et al., 2011; Hussey et al., 2015). It also o ers new capabilities to observe the ocean. In addition to collecting loca- tion and depth information useful for studying foraging behavior, these devices can...
Article
Full-text available
Polar oceans are poorly monitored despite the important role they play in regulating Earth’s climate system. Marine mammals equipped with biologging devices are now being used to fill the data gaps in these logistically difficult to sample regions. Since 2002, instrumented animals have been generating exceptionally large data sets of oceanographic...
Article
Full-text available
The surface mixed layer (ML) governs atmosphere-ocean fluxes, and thereby affects Earth's climate. Accurate representation of ML processes in ocean models remains a challenge, however. The O(100)m deep ML exhibits substantial horizontal thermohaline gradients, despite being near-homogenous vertically, making it an ideal location for processes that...
Article
Full-text available
Although some associations between the leatherback turtle Dermochelys coriacea and the Gulf Stream current have been previously suggested, no study has to date demonstrated strong affinities between leatherback movements and this particular frontal system using thorough oceanographic data in both the horizontal and vertical dimensions. The importan...
Article
Although some associations between the leatherback turtle Dermochelys coriacea and the Gulf Stream current have been previously suggested, no study has to date demonstrated strong affinities between leatherback movements and this particular frontal system using thorough oceanographic data in both the horizontal and vertical dimensions. The importan...
Conference Paper
Full-text available
Marine mammals help gather information on some of the harshest environments on the planet, through the use of miniaturized ocean sensors glued on their fur. Since 2004, hundreds of diving marine animals, mainly Antarctic and Arctic seals, have been fitted with a new generation of Argos tags developed by the Sea Mammal Research Unit of the Universit...
Article
Full-text available
The thermohaline structure of the Southern Ocean is deeply influenced by the presence of the Antarctic Circumpolar Current (ACC), where water masses of the World Ocean are advected, transformed and redistributed to the other basins. It remains a challenge to describe and visualize the complex 3D pattern of this circulation and its associated tracer...
Article
Full-text available
Marine mammals help gather information on some of the harshest environments on the planet, through the use of miniaturized ocean sensors glued on their fur. Since 2004, hundreds of diving marine animals, mainly Antarctic and Arctic seals, have been fitted with a new generation of Argos tags developed by the Sea Mammal Research Unit of the Universit...
Article
Full-text available
The oceanic mixed-layer is the gateway for the exchanges between the atmosphere and the ocean; in this layer all hydrographic ocean properties are set for months to millennia. A vast area of the Southern Ocean is seasonally capped by sea-ice, which alters the characteristics of the ocean mixed-layer. The interaction between the ocean mixed-layer an...
Conference Paper
Full-text available
Seals help gather information on some of the harshest environments on the planet, through the use of miniaturized ocean sensors glued on their fur. The resulting data – gathered from remote, icy seas over the last decade – are now freely available to scientists around the world from the data portal http://www. meop.net. The Polar oceans are changin...
Article
Full-text available
A fourth production region for the globally important Antarctic bottom water has been attributed to dense shelf water formation in the Cape Darnley Polynya, adjoining Prydz Bay in East Antarctica. Here we show new observations from CTD-instrumented elephant seals in 2011-2013 that provide the first complete assessment of dense shelf water formation...
Data
Supplementary Figures 1-4 and Supplementary Table 1
Article
West Antarctic ice shelves have thinned dramatically over recent decades. Oceanographic measurements that explore connections between offshore warming and transport across a continental shelf with variable bathymetry towards ice shelves are needed to constrain future changes in melt rates. Six years of seal-acquired observations provide extensive h...
Article
In the Southern Ocean, wide-ranging predators offer the opportunity to quantify how animals respond to differences in the environment because their behavior and population trends are an integrated signal of prevailing conditions within multiple marine habitats. Southern elephant seals in particular, can provide useful insights due to their circumpo...
Conference Paper
Full-text available
The circulation in the Western Equatorial Atlantic is characterized by a highly dynamic mesoscale activity that shapes the Guiana continental shelf. Olive ridley sea turtles (Lepidochelys olivacea) nesting in French Guiana cross this turbulent environment during their post-nesting migration. We studied how oceanographic and biological conditions dr...
Poster
Full-text available
In this study, we decompose objectively the thermohaline 3D structure of the Southern Ocean by applying a functional principal component analysis on temperature and salinity profiles from the Southern Ocean State Estimate (SOSE). It is found that 92% of the combined T-S variance is contained in two modes, providing an outstanding approximation of t...
Article
Full-text available
The circulation in the Western Equatorial Atlantic is characterized by a highly dynamic mesoscale activity that shapes the Guiana continental shelf. Olive ridley sea turtles (Lepidochelys olivacea) nesting in French Guiana cross this turbulent environment during their post-nesting migration. We studied how oceanographic and biological conditions dr...