Antoine Poteau

• Engineer at Sorbonne University

Quantifying the ocean’s ability to sequester atmospheric carbon is essential in a climate change context. Measurements of gravitational carbon export to the mesopelagic seldom balance the carbon demand or the oxygen consumption there, suggesting the potential presence of other mechanisms of carbon export. We deployed a biogeochemical Argo float in...

Photosynthetic available radiation (PAR) is the light usable by photosynthetic organisms. Photosynthetic available radiation measurements at depth are required to quantify the light availability for primary production. Direct PAR measurements may be measured with full‐spectrum quantum sensors for the range 400 to 700 nm. When spectrally resolved li...

Sinking biogenic particles are central to transporting carbon to depth. To date, studies have focused on quantifying the downward export flux from the epipelagic (0-100 m), often neglecting particle fate in the mesopelagic (100–1000 m) due to sampling issues. Particle fate is set by sinking speed and flux attenuation which determine penetration dep...

The effect of mesoscale features on the distribution of planktonic organisms are well documented. Yet, the interaction between these spatial features and the temporal scale, which can result in sudden increases of the planktonic biomass, is less known and not described at high resolution. A permanent mesoscale front in the Ligurian Sea (north-weste...

The Southern Ocean (SO) is known for its atypical bio‐optical regime. This complicates the interpretation of proxies measured from satellite and in situ platforms equipped with optical sensors, which occupy an important niche for monitoring the vast and remote SO. A ship‐based field study in concert with time series observations from BioGeoChemical...

The gravitational sinking of particles in the mesopelagic layer (∼200–1,000 m) transfers to the deep ocean a part of atmospheric carbon fixed by phytoplankton. This process, called the gravitational pump, exerts an important control on atmospheric CO2 levels but remains poorly characterized given the limited spatio‐temporal coverage of ship‐based f...

Intense glider monitoring was conducted in the Ligurian Sea for five months to capture the Net Community Production (NCP) variability in one of the most dynamic and productive regions of the Mediterranean Sea. Using the SeaExplorer glider technology, we were able to observe continuously from January to the end of May 2018 the physical and biogeoche...

Quantifying the ocean's ability to sequester atmospheric carbon is essential in a climate change context. Measurements of carbon exported to the mesopelagic seldom balance the carbon demand or the oxygen consumption there, suggesting the potential presence of other mechanisms of carbon export. We deployed a BGC Argo float in a cyclone in the Bengue...

Background: Biogeochemical-Argo floats are collecting an unprecedented number of profiles of optical backscattering measurements in the global ocean. Backscattering (BBP) data are crucial to understanding ocean particle dynamics and the biological carbon pump. Yet, so far, no procedures have been agreed upon to quality control BBP data in real time...

Background: Biogeochemical-Argo floats are collecting an unprecedented number of profiles of optical backscattering measurements in the global ocean. Backscattering (BBP) data are crucial to understanding ocean particle dynamics and the biological carbon pump. Yet, so far, no procedures have been agreed upon to quality control BBP data in real time...

In-situ fluorescence is a widely used method to estimate the chlorophyll-a (Chla) concentration, a proxy of the phytoplankton biomass. With the emergence of autonomous platforms such as BioGeoChemical-Argo (BGC-Argo) profiling floats, its use has expanded to global scale observations. However, the relationship between in-situ fluorescence and Chla...

This study assesses marine community production based on the diel variability of bio-optical properties monitored by two BioGeoChemical-Argo (BGC-Argo) floats. Experiments were conducted in two distinct Mediterranean systems, the northwestern Ligurian Sea and the central Ionian Sea, during summer months. We derived particulate organic carbon (POC)...

Measuring the underwater light field is a key mission of the international Biogeochemical-Argo program. Since 2012, 0–250 dbar profiles of downwelling irradiance at 380, 412 and 490 nm besides photosynthetically available radiation (PAR) have been acquired across the globe every 1 to 10 days. The resulting unprecedented amount of radiometric data h...

This study assesses marine biological production of organic carbon based on the diel variability of bio-optical properties monitored by two BioGeoChemical-Argo (BGC-Argo) floats. Experiments were conducted in two distinct Mediterranean systems, the Northwestern Ligurian Sea and the Central Ionian Sea during summer months. We derived particulate org...

Plain Language Summary The Levantine Sea, the easternmost area of Mediterranean Sea, is considered one of the poorest oceans on the Earth in terms of abundance of phytoplankton, the microscopic organisms that fuel the marine food web. However, historical data and satellite maps of chlorophyll (the pigment that reveals phytoplankton presence in the...

Stratified oceanic systems are characterized by the presence of a so‐called Deep Chlorophyll a Maximum (DCM) not detectable by ocean color satellites. A DCM can either be a phytoplankton (carbon) biomass maximum (Deep Biomass Maximum, DBM), or the consequence of photoacclimation processes (Deep photoAcclimation Maximum, DAM) resulting in the increa...

The shallower oxygen-poor water masses of the ocean confine a majority of the microbial communities that can produce up to 90 % of oceanic N2. This effective N2-yielding section encloses a suspended small-particle layer, inferred from particle backscattering (bbp) measurements. It is thus hypothesized that this layer (hereafter, the bbp-layer) is l...

The international array of profiling floats known as Argo is a major component of the global ocean-and climate-observing system. In 2010, the NAOS (Novel Argo Observing System) project was selected as part of France's Equipex "Investissement d'Avenir" program. The objectives of NAOS were to consolidate the French contribution to the Argo core missi...

The export and fate of organic carbon in the mesopelagic zone are still poorly understood and quantified due to lack of observations. We exploited data from a biogeochemical‐Argo float that was deployed in the Red Sea to study how a warm and hypoxic environment can affect the fate of the organic carbon in the ocean's interior. We observed that only...

Argo, the international array of profiling floats, is a major component of the global ocean and climate observing system. In 2010, the NAOS (Novel Argo Observing System) project was selected as part of the French “Investissements d’Avenir” Equipex program. The objectives of NAOS were to consolidate the French contribution to Argo’s core mission (gl...

Upper suboxic water masses confine a majority of the microbial communities that can produce up to 90 % of oceanic N2. This effective N2-yielding section encloses a suspended small-particle layer, inferred from particle backscattering (bbp) measurements. It is thus hypothesized that this layer (hereafter, the bbp-layer) is linked to N2-yielding micr...

The necessity of wide, global-scale observing systems for marine biogeochemistry emerged dramatically in the last decade. A global network based on Biogeochemical (BGC) Argo floats is considered to be one of the most promising approaches for reaching this goal. As a first step, pilot studies were encouraged to test the feasibility of a global BGC-A...

The Biogeochemical-Argo program (BGC-Argo) is a new profiling-float-based, ocean wide, and distributed ocean monitoring program which is tightly linked to, and has benefited significantly from, the Argo program. The community has recommended for BGC-Argo to measure six additional properties in addition to pressure, temperature and salinity measured...

Understanding spatial and temporal dynamics of non-algal particles in open ocean is of the utmost importance to improve estimations of carbon export and sequestration. These particles covary with phytoplankton abundance but also accumulate independently of algal dynamics. The latter likely represents an important fraction of organic carbon, but it...

This document is the BGC-Argo quality control manual for radiometry observations. This first version of the document is to apply an initial QC to all radiometry values. Except for data failing the following tests, all the other values will be flagged as probably good data (‘2’). Probably good data need to be validated (i.e., flagged as good “1”) i...

As commonly observed in oligotrophic stratified waters, a subsurface (or deep) chlorophyll maximum (SCM) frequently characterizes the vertical distribution of phytoplankton chlorophyll in the Mediterranean Sea. Occurring far from the surface layer “seen” by ocean colour satellites, SCMs are difficult to observe with adequate spatio-temporal resolut...

Subsurface (or Deep) Chlorophyll a Maxima (SCMs) are frequently observed in stratified oligotrophic waters. They result from various mechanisms, e.g. photoacclimation of phytoplankton organisms or actual increase in phytoplankton carbon biomass. SCMs are difficult to observe with adequate spatio-temporal resolution. Hence their spatio-temporal dyna...

As commonly observed in oligotrophic stratified waters, a Subsurface (or Deep) Chlorophyll Maximum (SCM) frequently characterizes the vertical distribution of phytoplankton chlorophyll in the Mediterranean Sea. Occurring far from the surface layer seen by ocean color satellites, SCMs are difficult to observe with adequate spatio-temporal resolution...

We report on data from an oceanographic cruise, covering western, central and eastern parts of the Mediterranean Sea, on the French research vessel Tethys 2 in May 2015. This cruise was fully dedicated to the maintenance and the metrological verification of a biogeochemical observing system based on a fleet of BGC-Argo floats. During the cruise, a...

The South Pacific Subtropical Gyre (SPSG) is a vast and remote area where large uncertainties on variability in phytoplankton biomass and production remain due to the lack of biogeochemical in situ observations. In such oligotrophic environments, ecosystems are predominantly controlled by nutrients depletion in surface waters. However, this oligotr...

Characterizing phytoplankton distribution and dynamics in the world's open oceans requires in situ observations over a broad range of space and time scales. In addition to temperature/salinity measurements, Biogeochemical-Argo (BGC-Argo) profiling floats are capable of autonomously observing at high frequency bio-optical properties such as the chlo...

Since 2012, an array of 105 Biogeochemical-Argo (BGC-Argo) floats has been deployed across the world's oceans to assist in filling observational gaps that are required for characterizing open-ocean environments. Profiles of biogeochemical (chlorophyll and dissolved organic matter) and optical (single-wavelength particulate optical backscattering, d...

We report on data from an oceanographic cruise, covering western, central and eastern parts of the Mediterranean Sea, on the French research vessel Tethys 2 in May 2015. This cruise was fully dedicated to the maintenance and the metrological verification of a biogeochemical observing system based on a fleet of BGC-Argo floats. During the cruise, a...

In mid-and high-latitude oceans, winter surface cooling and strong winds drive turbulent mixing that carries phytoplankton to depths of several hundred metres, well below the sunlit layer. This downward mixing, in combination with low solar radiation, drastically limits phytoplankton growth during the winter, especially that of the diatoms and othe...

The Southern Ocean (SO) hosts plankton communities that impact the biogeochemical cycles of the global ocean. However, weather conditions in the SO restrict mainly in situ observations of plankton communities to spring and summer, preventing the description of biological successions at an annual scale. Here, we use shipboard observations collected...

Since 2012, an array of 105 Biogeochemical (BGC) Argo floats has been deployed across the world’s oceans to fill the observational gap characterizing most of open-ocean environments. Profiles of biogeochemical (chlorophyll and fluorescent dissolved organic matter) and optical (single-wavelength particulate optical backscattering, downward irradianc...

Continuous observations during 3 years with a vertical resolution of 1 dbar from two Bio-Argo floats in the Black Sea that were equipped with oxygen optodes, chlorophyll fluorometers, and backscattering sensors are analyzed. The particle backscattering coefficient, bbp provides a proxy for the concentration of suspended particles. The observations...

We explore a novel and spatially extensive data set obtained from Biogeochemical-Argo (or BGC-Argo) floats, containing 16,796 profiles of the particulate backscattering coefficient at 700 nm (bbp(700)) measured with three different sensors. We focus at the 900–950m depth interval (within the mesopelagic), where we found values to be relatively cons...

The South Pacific subtropical gyre is a vast and remote area where biogeochemical in situ observations are scarce, leading to large uncertainties on phytoplankton biomass variability. Here, we investigated physical and biogeochemical observations issued from three Biogeochemical-Argo (BGC-Argo) profiling floats that collected data in the central So...

Ocean color observations enable the estimation of bio-optical proxies of phytoplankton biomass in the surface layer of the ocean quasi-synoptically. In parallel, the Argo program distributes vertical profiles of the ocean physical properties with a high spatio-temporal resolution. Thus, we developed new learning-based methods taking advantage of th...

Chlorophyll fluorometers provide the largest in situ global data set for estimating phytoplankton biomass because of their ease of use, size, power consumption, and relatively low price. While in situ chlorophyll a (Chl) fluorescence is proxy for Chl a concentration, and hence phytoplankton biomass, there exist large natural variations in the relat...

The presented database includes 0-1000 m vertical profiles of bio-optical and biogeochemical variables acquired by autonomous profiling Biogeochemical-Argo (BGC-Argo) floats. Data have been collected between October 2012 and January 2016, around local noon, in several oceanic areas encompassing the diversity of ocean's trophic environments. The dat...

In situ chlorophyll fluorometers have been widely employed for more than half a century, and to date, it still remains the most used instrument to estimate chlorophyll-a concentration in the field, especially for measurements onboard autonomous observation platforms, e.g., Bio-Argo floats and gliders. However, in deep waters (> 300 m) of some speci...

The database here presented includes quality-controlled bio-optical and biogeochemical variables derived from autonomous profiling Biogeochemical Argo float measurements, and supports field and remote ocean colour applications. Data represent the first optical depth (i.e., the layer of interest for satellite remote sensing) and have been collected...

This document does NOT address the issue of nitrate quality control (either real-time or delayed mode). As a preliminary step towards that goal, this document seeks to ensure that all countries deploying floats equipped with nitrate sensors document the data and metadata related to these floats properly. We produced this document in response to act...

An array of Bio-Argo floats equipped with radiometric sensors has been recently deployed in various open ocean areas representative of the diversity of trophic and bio-optical conditions prevailing in the so-called case 1 waters. Around solar noon and almost every day, each float acquires 0–250-m vertical profiles of photosynthetically available ra...

The present study proposes a novel method that merges satellite ocean-color bio-optical products with Argo temperature-salinity profiles to infer the vertical distribution of the particulate backscattering coefficient (bbp). This neural network-based method (SOCA-BBP for Satellite Ocean-Color merged with Argo data to infer the vertical distribution...

This study focuses on the analysis of more than 5715 profiles collected by 44 Bio-Argo floats in various hydrological and trophic conditions of the global open ocean. Our objective is two-fold: (i) we explore the relationships between the measured bio-optical properties at the regional, seasonal and vertical scales; (ii) we interpret the observed d...

In 2013, as part of the French NAOS (Novel Argo Oceanic observing System) program, five profiling floats equipped with nitrate sensors (SUNA-V2) together with CTD and bio-optical sensors were deployed in the Mediterranean Sea. At present day, more than 500 profiles of physical and biological parameters were acquired, and significantly increased the...

Context: The Southern Ocean (SO) is the most remote and the least understood of the world's oceans, although it plays a crucial role in past and present climate state and changes. It is unique in being the only zonally unbounded ocean. For this reason, it is the major link by which water properties are exchanged among the other oceans. Moreover, th...

Characterizing phytoplankton phenology and spatio-temporal variability requires in situ observations over a broad range of space and time scales. Bio-Argo profiling floats, are capable of measuring at high frequency and at the basin scale a variety of bio-optical properties such as chlorophyll fluorescence, a proxy of chlorophyll concentration (Chl...

Seasonal variability of nutrient concentrations in the Mediterranean Sea: Contribution of Bio-Argo floats

Based on in situ datasets collected using two Bio-Argo floats deployed in the sub-polar North Atlantic from June, 2008 to May, 2010, the present study focuses on the seasonal variability of three bio-optical properties, i.e. chlorophyll-a concentration ([Chla]), particle backscattering coefficient at 532 nm (bbp(532)), and particle beam attenuation...

Two profiling floats, equipped with nitrate concentration sensors were deployed in the North Western Mediterranean from summer 2012 to summer 2013. Satellite ocean colour data were extracted to evaluate surface chlorophyll concentration at float locations. Time-series of mixed layer depths, nitrate and chlorophyll concentration were analysed to cha...

We deployed four Bio-Argo profiling floats in various oligotrophic locations of the Pacific subtropical gyres and Mediterranean Sea to address the seasonal phytoplankton dynamics in the euphotic layer and explore its dependence on light regime dynamics. Results show that there is a similar phytoplankton biomass seasonal pattern in the four observed...

The objectives of this study are to: (i) compare the potential of the Moderate Resolution Imaging Spectroradiometer (MODIS), the Medium Resolution Imaging Spectrometer (MERIS) and the Geostationary Ocean Color Imager (GOCI) in retrieving the particulate backscattering coefficient, robust proxy of the concentration of suspended particulate matter (S...

MyOcean In Situ TAC: A new in situ service for operational and research communities Using In Situ TAC products to view the early February 2013 Storm over the Iberian Irish (IBI) area French Argo float deployment from opportunity vessels in 2012 MOOSE: Mediterranean data management link with Coriolis European contributions to SPURS (Salinity Process...

Understanding the ocean carbon cycle requires a precise assessment of phytoplankton biomass in the oceans. In terms of numbers of observations, satellite data represent the largest available data set. However, as they are limited to surface waters, they have to be merged with in situ observations. Amongst the in situ data, fluorescence profiles con...

Eight autonomous profiling "Bio-Argo" floats were deployed offshore during about 2 years (2008-2010) in Pacific, Atlantic, and Mediterranean zones. They were equipped with miniaturized bio-optical sensors, namely a radiometer measuring within the upper layer the downward irradiance at 412, 490, and 555 nm, and two fluorometers for detection of chlo...

Delays in seismic P wave are used to make scans or 3D images of the variations in seismic wave speed in the Earth's interior using the techniques of seismic tomography. Observations of such delays are ubiquitous on the continents but rare in oceanic regions. Free-drifting profiling floats that measure the temperature, salinity and current of the up...

Understanding the ocean carbon cycle requires a precise assessment of phytoplankton biomass in the oceans. In terms of numbers of observations, satellite data represents the largest available data set. However, as they are limited to surface waters, they have to be merged with in situ observations. Amongst the in situ data, fluorescence profiles co...

Eight autonomous profiling floats equipped with miniaturized radiometers and fluorimeters have collected data in Pacific, Atlantic, and Mediterranean offshore zones. They measured in particular 0-400 m vertical profiles of the downward irradiance at three wavelengths (412, 490, and 555 nm) and of the chlorophyll a fluorescence. Such autonomous sens...

In vivo fluorescence of Chlorophyll-a (Chl-a) is a potentially useful property to study the vertical distribution of phytoplankton biomass. However the technique is presently not fully exploited as it should be, essentially because of the difficulties in converting the fluorescence signal into an accurate Chl-a concentration. These difficulties ari...

The SIMBADA radiometer was designed to check the radiometric calibration of satellite ocean-color sensors and evaluate the atmospheric correction of ocean-color imagery. It measures marine reflectance and aerosol optical thickness in 11 spectral bands covering the spectral range 350 to 870 nm. Aerosol optical thickness is obtained by viewing the su...

This document is a synopsis of the joint work of the PABIM (Platforms for Biogeochemical studies: Instrumentation and Measure) project team, which groups more than 20 scientists strongly involved in scientific activities related to the exploitation and the use of autonomous platforms for biogeochemical oceanic observations. The present white book s...

LOISEL, H., MERIAUX, X., POTEAU, A., ARTIGAS L. F., A., LUBAC B., GARDEL A., CAILLAUD J., LESOURD S. 2009. Analyze of the inherent optical properties of French Guyana coastal waters for remote sensing applications, SI 56 (Proceedings of the 10th International Coastal Symposium), 1532 - 1536. Lisbon, Portugal, ISBN The development of bio-optical alg...

The variability of the backscattering to scattering ratio of marine particles, bbp:bp, is examined from in situ measurements performed during the spring and early summer of 2004 in the eastern English Channel and southern North Sea. This area is characterized by a quasi-permanent background of mineral matter from direct inputs, or resuspension effe...

Detecting phytoplankton species from remote sensing is essential to map and monitor algal blooms in coastal waters, but stays a challenge because of the interference of suspended sediments and dissolved organic matter with the phytoplankton signal. In the eastern English Channel and the south North Sea, a more or less intensive bloom of prymnesioph...

Knowledge of the relative proportion between small-sized and larger particles in the surface ocean is essential to understand the ocean ecology and biogeochemistry, including particle dynamics and carbon cycling. We show that this information may be assessed qualitatively from satellite observations of ocean color. Such capability is based on the e...

During spring and summer 2004, intensive field campaigns were conducted in the Eastern English Channel. This region is characterized by relatively intense phytoplankton blooms, low bathymetry, strong tide ranges and great river inputs. The sampling period accounts for episodic blooms of prymnesiophyceae Phaeocystis globosa and diatoms. Hyperspectra...

The investigation s main objective is to collect from platforms of opportunity (merchant ships, research vessels) concomitant normalized water-leaving radiance and aerosol optical thickness data over the world s oceans. A global, long-term data set of these variables is needed to verify whether satellite retrievals of normalized water-leaving radia...

The second SIMBIOS (Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies) Radiometric Intercomparison (SIMRIC-2) was carried out in 2002. The purpose of the SIMRICs is to ensure a common radiometric scale among the calibration facilities that are engaged in calibrating in-situ radiometers used for ocean color relat...

This report describes the first Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Radiometric Intercomparison (SIMRIC-1). The purpose of the SIMRIC-1 is to ensure a common radiometric scale among the calibration facilities that are engaged in calibrating in situ radiometers used for ocean colour-relate...

The activities of the SIMBIOS (Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies) Project Office include calibration round-robin intercomparison experiments. The laboratories participating in these round-robins include academic institutions, government agencies and instrument manufacturers that are involved in o...

In this study, we try to improve the understanding of the polarization of the signal reflected by the water body for which an accurate knowledge is necessary in remote-sensing applications. We only detail the alpha (pol) factor defined as the ratio between the vertically polarized to the total (unpolarized) marine reflectance. In the validation pla...