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Frédéric Gazeau

Frédéric Gazeau
Institut de la Mer de Villefranche · Laboratoire d'Océanographie de Villefranche

PhD - HDR

About

100
Publications
37,598
Reads
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4,676
Citations
Additional affiliations
January 2019 - present
Institut de la Mer de Villefranche
Position
  • Researcher
May 2015 - December 2018
Observatoire Océanologique de Villefranche sur Mer
Position
  • Group Leader
February 2009 - May 2015
Observatoire Océanologique de Villefranche sur Mer
Position
  • CNRS Researcher
Education
April 2001 - October 2004
University of Liège
Field of study
  • Marine Biology
April 2001 - October 2004
Sorbonne Université
Field of study
  • Marine biology

Publications

Publications (100)
Article
Full-text available
In the Western Tropical South Pacific, a hotspot of dinitrogen-fixing organisms has been identified. The survival of these species depends on the availability of dissolved iron (DFe); however, the source of this DFe is still unclear. DFe was measured along a transect from 175°E to 166°W near 19-21°S. The distribution of DFe showed high spatial vari...
Article
Full-text available
In the oligotrophic waters of the Mediterranean Sea, during the stratification period, the microbial loop relies on pulsed inputs of nutrients through the atmospheric deposition of aerosols from both natural (e.g., Saharan dust), anthropogenic, or mixed origins. While the influence of dust deposition on microbial processes and community composition...
Article
Full-text available
N2 fixation rates were measured in the 0–1000 m layer at 13 stations located in the open western and central Mediterranean Sea (MS) during the PEACETIME cruise (late spring 2017). While the spatial variability in N2 fixation was not related to Fe, P nor N stocks, the surface composition of the diazotrophic community indicated a strong longitudinal...
Article
Full-text available
Although atmospheric dust fluxes from arid as well as human-impacted areas represent a significant source of nutrients to surface waters of the Mediterranean Sea, studies focusing on the evolution of the metabolic balance of the plankton community following a dust deposition event are scarce, and none were conducted in the context of projected futu...
Article
Full-text available
In low-nutrient low-chlorophyll areas, such as the Mediterranean Sea, atmospheric fluxes represent a considerable external source of nutrients likely supporting primary production, especially during periods of stratification. These areas are expected to expand in the future due to lower nutrient supply from sub-surface waters caused by climate-driv...
Preprint
Full-text available
In the oligotrophic waters of the Mediterranean Sea, during the stratification period, the microbial loop relies on pulsed inputs of nutrients through atmospheric deposition of aerosols from both natural (Saharan dust) and anthropogenic origins. While the influence of dust deposition on microbial processes and community composition is still not ful...
Article
Full-text available
Lithogenic elements such as aluminum (Al), iron (Fe), rare earth elements (REEs), thorium (232Th and 230Th, given as Th) and protactinium (Pa) are often assumed to be insoluble. In this study, their dissolution from Saharan dust reaching Mediterranean seawater was studied through tank experiments over 3 to 4 d under controlled conditions including...
Preprint
Full-text available
Although atmospheric dust fluxes from arid as well as human-impacted areas represent a significant source of nutrients to surface waters of the Mediterranean Sea, studies focusing on the evolution of the metabolic balance of the plankton community following a dust deposition event are scarce and none were conducted in the context of projected futur...
Preprint
Full-text available
In Low Nutrient Low Chlorophyll areas, such as the Mediterranean Sea, atmospheric fluxes represent a considerable external source of nutrients likely supporting primary production especially during stratification periods. These areas are expected to expand in the future due to lower nutrient supply from sub-surface waters caused by enhanced stratif...
Preprint
Full-text available
The release of lithogenic elements (which are often assumed to be insoluble) such as Aluminum (Al), Iron (Fe), Rare Earth Elements (REE), Thorium (Th) and Protactinium (Pa) by Saharan dust reaching Mediterranean seawater was studied through tank experiments over 3 to 4 days under controlled conditions including control without dust addition and dus...
Article
Full-text available
Ocean acidification is thought to benefit seagrasses because of increased carbon dioxide (CO2) availability for photosynthesis. However, in order to truly assess ecological responses, effects of ocean acidification need to be investigated in a variety of coastal environments. We tested the hypothesis that ocean acidification would benefit seagrasse...
Article
Full-text available
Coral reefs are constructed by calcifiers that precipitate calcium carbonate to build their shells or skeletons through the process of calcification. Accurately assessing coral calcification rates is crucial to determine the health of these ecosystems and their response to major environmental changes such as ocean warming and acidification. Several...
Article
Full-text available
The energetically costly transition from free-swimming larvae to benthic life stage and maintenance of a calcareous structure can make calcifying marine invertebrates vulnerable to ocean acidification. The first goal of this study was to evaluate the impacts of ocean acidification on calcified tube growth for two Serpulidae polychaete worms. Spiror...
Article
Full-text available
Free Ocean CO2 Enrichment (FOCE) experiments are a relatively recent development in ocean acidification research, designed to address the need for in situ, long-term, community level experiments. FOCE studies have been conducted across different marine benthic habitats and regions, from Antarctica to the tropics. Based on this previous research we...
Article
Full-text available
Marine sediments are an important carbonate reservoir whose partial dissolution could buffer seawater pH decreases in the water column as a consequence of anthropogenic CO2 uptake by the ocean. This study investigates the impact of ocean acidification on the carbonate chemistry at the sediment-water interface (SWI) of shallow-water carbonate sedime...
Article
Alterations to colonization or early post-settlement stages may cause the reorganization of communities under future ocean acidification conditions. Yet, this hypothesis has been little tested by in situ pH manipulation. A Free Ocean Carbon Dioxide Enrichment (FOCE) system was used to lower pH by a ~ 0.3 unit offset within a partially enclosed port...
Article
The Mediterranean basin receives among the highest dust fluxes in the world ocean, and also appears to be one of the regions the most strongly impacted by ocean acidification. The aim of this study was to assess, on a short time scale (one-week), the effect of ocean acidification on the dissolution of nutrients (inorganic nitrogen, phosphate and ir...
Article
Full-text available
Coastal time series of ocean carbonate chemistry are critical for understanding how global anthropogenic change manifests in near-shore ecosystems. Yet, they are few and have low temporal resolution. At the time series station Point B in the northwestern Mediterranean Sea, seawater was sampled weekly from 2007 through 2015, at 1 and 50 m, and analy...
Article
Full-text available
Alterations in seagrass epiphytic communities are expected under future ocean acidification conditions, yet this hypothesis has been little tested in situ. A Free Ocean Carbon Dioxide Enrichment system was used to lower pH by a ~0.3 unit offset within a partially enclosed portion (1.7 m3) of a Posidonia oceanica meadow (11 m depth) between June 21 a...
Article
Full-text available
The evolution of organic carbon export to the deep ocean, under anthropogenic forcing such as ocean warming and acidification, needs to be investigated in order to evaluate potential positive or negative feedbacks on atmospheric CO2 concentrations, and therefore on climate. As such, modifications of aggregation processes driven by transparent exopo...
Data
Heterotrophic prokaryote abundance (cell mL-1) along the course of the three CHIPIE experiments in the two minicosms (non-acidified and acidified). (TIF)
Data
Concentration of dissolved organic carbon ([DOC] in μmol L-1) along the course of the three CHIPIE experiments in the two minicosms (non-acidified and acidified). “C1” and “C2” refer to samplings performed before and after acidification, respectively. The x-axis (in log-scale) represents the number of hours after the artificial dust deposition at t...
Article
Oligotrophic areas account for about 30% of oceanic primary production and are projected to expand in a warm, high-CO2 world. Changes in primary production in these areas could have important impacts on future global carbon cycling. To assess the response of primary production and respiration of plankton communities to increasing partial pressure o...
Article
In order to identify how ocean acidification will influence biological interactions and fluxes among planktonic organisms and across trophic levels, a large-scale mesocosm experiment was performed in the oligotrophic Northwestern Mediterranean Sea in the framework of the European MedSeA project. Nine mesocosms were deployed in the Bay of Calvi (Cor...
Article
The frequency of lytically infected and lysogenic cells (FLIC and FLC, respectively) was estimated during an in situ mesocosm experiment studying the impact of ocean acidification on the plankton community of a low nutrient low chlorophyll (LNLC) system in the north-western Mediterranean Sea (Bay of Villefranche, France) in February/March 2013. No...
Presentation
Full-text available
Abstract of my EGU presentation about the sediment acidification experiment (ACIBIOS) we carried out in 2015 at the Laboratoire Océanographique de Villefranche sur Mer. An article is in progress.
Article
Full-text available
Seagrass is expected to benefit from increased car- bon availability under future ocean acidification. This hypothesis has been little tested by in situ manipulation. To test for ocean acidification effects on seagrass meadows under controlled CO2/pH conditions, we used a Free Ocean Carbon Dioxide Enrichment (FOCE) system which allows for the manip...
Article
The effects of elevated partial pressure of CO2 (pCO2) on plankton communities in oligotrophic ecosys- tems were studied during two mesocosm experiments: one during summer 2012 in the Bay of Calvi, France, and another during winter 2013 in the Bay of Villefranche, France. Here we report on the relative abundances of coccolithophores versus siliceou...
Article
The effects of ocean acidification on nitrogen (N2) fixation rates and on the community composition of N2-fixing microbes (diazotrophs) were examined in coastal waters of the North-Western Mediterranean Sea. Nine experimental mesocosm enclosures of ∼50 m3 each were deployed for 20 days during June-July 2012 in the Bay of Calvi, Corsica, France. Thr...
Article
Two pelagic mesocosm experiments were conducted to study the impact of ocean acidification on Mediterranean plankton communities. A first experiment took place in summer 2012 in the Bay of Calvi (France) followed by an experiment in winter 2013 in the Bay of Villefranche (France) under pre-bloom conditions. Nine mesocosms were deployed: three serve...
Data
1. Biological interactions can alter predictions that are based on single-species physiological response. It is known that leaf segments of the seagrass Posidonia oceanica will increase photosynthesis with lowered pH, but it is not clear whether the outcome will be altered when the whole plant and its epiphyte community, with different respiratory...
Article
1.Biological interactions can alter predictions that are based on single species physiological response. It is known that leaf segments of the seagrass Posidonia oceanica will increase photosynthesis with lowered pH but, it is not clear whether the outcome will be altered when the whole plant and its epiphyte community, with different respiratory a...
Article
Full-text available
Human-induced climate change and ocean acidification are global environmental phenomena with a common driver: anthropogenic emissions of carbon dioxide. Both processes potentially threaten the Mediterranean bivalve mollusc aquaculture sector, which is economically relevant to several regions and countries. Detrimental effects on bivalve mollusc spe...
Article
Notwithstanding the increasing amount of researches on the effect of ocean acidification (OA) on marine ecosystems, no consent has emerged on its consequences on many prokaryote-mediated processes. Two mesocosm experiments were performed in coastal Mediterranean areas with different trophic status: the summer oligotrophic Bay of Calvi (BC, Corsica,...
Article
Full-text available
Abstract. The effect of ocean acidification and changing water conditions on primary marine aerosol emissions is not well understood on a regional or a global scale. To investigate this effect as well as the indirect effect on aerosol that changing biogeochemical parameters can have, ~52 m3 pelagic mesocosms were deployed for several weeks in the M...
Conference Paper
Full-text available
A large-scale in situ mesocosm experiment was performed in June/July 2012 at Bay of Calvi (Western Mediterranean Sea) in order to better understand the response of zooplankton to ocean acidification. We examined: the mesozooplankton abundance, the egg and nauplius stocks and the feeding rates of Acartia clausi, Centropages typicus at different pCO...
Article
Full-text available
Among current methods used to estimate calcification rates, the alkalinity anomaly technique has been widely used for short-term incubations as it is nondestructive and is based on a parameter that is easily and accurately measured. However, total alkalinity is also influenced by other processes such as nutrient consumption and release, and may als...
Conference Paper
Full-text available
Effects of ocean acidification on the polychaetes : Spirobranchus triqueter and Spirorbis spirorbis V. Díaz-Castañeda, J. Dellile, F. Gazeau, E. Cox, J.P. Gattuso Marine calcifiers are among the most vulnerable to ocean acidification. We examined the effect of pH levels 7.4, 7.8 and 8.1 (pH on the total scale) on the growth of tubes of the serpuli...
Article
Full-text available
In order to assess the effects of ocean acidification and warming on the Mediterranean mussel (Mytilus galloprovincialis), specimens were reared in aquarium tanks and exposed to elevated conditions of temperature (+3°C) and acidity (−0.3 pH units) for a period of 10 months. The whole system comprised a factorial experimental design with 4 treatment...
Chapter
Ocean acidification corresponds to a decrease in the pH of the ocean over long (10 or more years) periods of time, which is mainly caused by the uptake of atmospheric CO2. Seawater carbonate chemistry has undergone large changes on a geological scale as well as since the beginning of the Industrial Revolution. This chapter aims to characterize not...
Article
The effect of ocean warming and acidification was investigated on a natural plankton assemblage from an oligotrophic area, the bay of Villefranche (NW Mediterranean Sea). The assemblage was sampled in March 2012 and exposed to the following four treatments for 12 days: control (∼360 μatm, 14°C), elevated pCO2 (∼610 μatm, 14°C), elevated temperature...
Article
Full-text available
Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster...
Article
Full-text available
Free Ocean CO2 Enrichment (FOCE) systems are designed to assess the impact of ocean acidification on biological communities in situ for extended periods of time (weeks to months). They overcome some of the drawbacks of laboratory experiments and of field observations by enabling (1) precise control of CO2 enrichment by monitoring pH as an offset of...
Data
In order to assess the effects of ocean acidification and warming on the Mediterranean mussel (Mytilus galloprovincialis), specimens were reared in aquarium tanks and exposed to elevated conditions of temperature (+3°C) and acidity (-0.3 pH units) for a period of 10 months. The whole system comprised a factorial experimental design with 4 treatment...
Data
The effect of ocean warming and acidification was investigated on a natural plankton assemblage from an oligotrophic area, the bay of Villefranche (NW Mediterranean Sea). The assemblage was sampled in March 2012 and exposed to the following four treatments for 12 days: control ( 360 µatm, 14°C), elevated pCO2 ( 610 µatm, 14°C), elevated temperature...
Data
Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster...
Article
Full-text available
Over the next century, elevated quantities of atmospheric CO2 are expected to penetrate into the oceans, causing a reduction in pH (-0.3/-0.4 pH unit in the surface ocean) and in the concentration of carbonate ions (so-called ocean acidification). Of growing concern are the impacts that this will have on marine and estuarine organisms and ecosystem...