Brivaela Moriceau

Brivaela Moriceau
Université de Bretagne Occidentale | UBO · Institut Universitaire Européen de la Mer (IUEM)

PhD

About

58
Publications
19,398
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,096
Citations
Citations since 2016
30 Research Items
1612 Citations
20162017201820192020202120220100200300
20162017201820192020202120220100200300
20162017201820192020202120220100200300
20162017201820192020202120220100200300
Introduction
Marine biogeochemist, specialist of the marine silicon cycle and its link with the carbon biological pump, I study the variability of two main processes involved in the export of matter by diatoms: the remineralization of diatom, bSiO2 and diatom POC and the factors changing the sinking rates, such as aggregation and grazing.
Additional affiliations
March 2009 - present
Université de Bretagne Occidentale
Position
  • CNRS researcher
January 2006 - January 2008
Stony Brook University
Position
  • PostDoc Position
September 2002 - May 2003

Publications

Publications (58)
Article
Full-text available
The Green Edge project was designed to investigate the onset, life, and fate of a phytoplankton spring bloom (PSB) in the Arctic Ocean. The lengthening of the ice-free period and the warming of seawater, amongst other factors, have induced major changes in Arctic Ocean biology over the last decades. Because the PSB is at the base of the Arctic Ocea...
Preprint
The Green Edge project was designed to investigate the onset, life and fate of a phytoplankton spring bloom (PSB) in the Arctic Ocean. The lengthening of the ice-free period and the warming of seawater, amongst other factors, have induced major changes in arctic ocean biology over the last decades. Because the PSB is at the base of the Arctic Ocean...
Preprint
Full-text available
In the last decades, the Arctic Ocean has been affected by climate change, leading to alterations in the sea ice cover that influence the phytoplankton spring bloom, its associated food web, and therefore carbon sequestration. During the Green Edge 2016 expedition in central Baffin Bay, the phytoplankton spring bloom and its development around the...
Article
Full-text available
In the last decades, the Arctic Ocean has been affected by climate change, leading to alterations in the sea ice cover that influence the phytoplankton spring bloom, its associated food web, and therefore carbon sequestration. During the Green Edge 2016 expedition in the central Baffin Bay, the phytoplankton spring bloom and its development around...
Article
Full-text available
We examined biogenic silica production and elementary composition (biogenic Si, particulate organic carbon and particulate organic nitrogen) of Rhizaria and diatoms in the upper 200 m along a transect in the Southwest Pacific sector of the Southern Ocean during austral summer (January-February 2019). From incubations using the 32 Si radioisotope, s...
Preprint
The aim of this work was to determine the impact of sympagic (ice-associated) algal primary production on the quality of Arctic filter-feeding bivalves. For this purpose, we investigated the sea ice production of lipids (including omega−3 polyunsaturated fatty acids (n-3 PUFA) and highly branched isoprenoids (HBI)), as well as their subsequent inco...
Article
Full-text available
The aim of this work was to determine the impact of sympagic (ice-associated) algal primary production on the quality of Arctic filter-feeding bivalves. For this purpose, we investigated the sea ice production of lipids (including omega−3 polyunsaturated fatty acids (n- 3 PUFA) and highly branched isoprenoids (HBI)), as well as their subsequent inc...
Article
Diatoms in general, and Thalassiosira weissflogii (T. weissflogii) in particular, are among the most ubiquitous phytoplanktonic species while, phosphorus (P) is an essential nutrient that limits productivity in many oceanic regimes. To investigate how T. weissflogii cultures grown under different P regimes are chemically altered before and during t...
Article
Phosphorus (P) limitation of phytoplankton growth is known to affect the accumulation and release of carbohydrates (CHO) by micro-algae. However, relatively little is known about the fate of algal exudates, notably their bacterial degradation. The CHO chemical characterization is also not exhaustive, especially in “functional” pools relevant for ph...
Article
Full-text available
The Green Edge initiative was developed to investigate the processes controlling the primary productivity and fate of organic matter produced during the Arctic phytoplankton spring bloom (PSB) and to determine its role in the ecosystem. Two field campaigns were conducted in 2015 and 2016 at an ice camp located on landfast sea ice southeast of Qikiq...
Article
Full-text available
In marine ecosystems, carbon export is driven by particle flux which is modulated by aggregation, remineralization, and grazing processes. Zooplankton contribute to the sinking flux through the egestion of fast sinking fecal pellets but may also attenuate the flux by tearing apart phytoplankton aggregates into small pieces through swimming activity...
Article
Numerical simulations of ocean biogeochemical cycles need to adequately represent particle sinking velocities (SV). For decades, Stokes' Law estimating particle SV from density and size has been widely used. But while Stokes' Law holds for small, smooth, and rigid spheres settling at low Reynolds number, it fails when applied to marine aggregates c...
Article
Full-text available
The Arctic Ocean is particularly affected by climate change, with changes in sea ice cover expected to impact phytoplankton primary production. During the Green Edge expedition, the development of the late spring–early summer diatom bloom was studied in relation with the sea ice retreat by multiple transects across the marginal ice zone. Biogenic s...
Article
Full-text available
The Arctic Ocean is particularly affected by climate change, with changes in sea ice cover expected to impact phytoplankton primary production. During the Green Edge expedition, the development of the late spring–early summer diatom bloom was studied in relation with the sea ice retreat by multiple transects across the marginal ice zone. Biogenic s...
Article
Full-text available
The Arctic Ocean is particularly affected by climate change, with changes in sea ice cover expected to impact phytoplankton primary production. During the Green Edge expedition, the development of the late spring–early summer diatom bloom was studied in relation with the sea ice retreat by multiple transects across the marginal ice zone. Biogenic s...
Article
Full-text available
The Green Edge initiative was developed to investigate the processes controlling the primary productivity and the fate of organic matter produced during the Arctic phytoplankton spring bloom (PSB) and to determine its role in the ecosystem. Two field campaigns were conducted in 2015 and 2016 at an ice camp located on landfast sea ice southeast of Q...
Presentation
Full-text available
Within the marine realm, diatoms play a major role in carbon export mainly when they aggregate. Another efficient export pathway is zooplankton faecal pellets emission in the surface mixed layer or after vertical migration in the mesopelagic layers. When diatoms are grazed by large copepods their frustule may ballast the resulting faecal pellets an...
Article
The potential presence of nanoplastics (NP) in aquatic environments represents a growing concern regarding their possible effects on aquatic organisms. The objective of this study was to assess the impact of polystyrene (PS) amino-modified particles (50 nm PSeNH2) on the cellular and metabolic responses of the diatom Chaetoceros neogracile cultures...
Article
Full-text available
The fraction of net primary production that is exported from the euphotic zone as sinking particulate organic carbon (POC) varies notably through time and from region to region. Phytoplankton containing biominerals, such as silicified diatoms have long been associated with high export fluxes. However, recent reviews point out that the magnitude of...
Article
Full-text available
Diatom production is mainly supported by the dissolution of biogenic silica (bSiO2) within the first 200 m of the water column. The upper oceanic layer is enriched in dissolved and/or colloidal organic matter, such as exopolymeric polysaccharides (EPS) and transparent exopolymeric particles (TEP) excreted by phytoplankton in large amounts, especial...
Poster
Full-text available
Diatom production is mainly supported by the dissolution of biogenic silica (bSiO2) within the first 200 meters of the water column. The upper oceanic layer is enriched in dissolved and/or colloidal organic matter, such as exopolymeric polysaccharides (EPS) and transparent exopolymeric particles (TEP) excreted by phytoplankton in large amounts, esp...
Article
Diatoms sustain the marine food web and contribute to the export of carbon from the surface ocean to depth. They account for about 40% of marine primary productivity and particulate carbon exported to depth as part of the biological pump. Diatoms have long been known to be abundant in turbulent, nutrient-rich waters, but observations and simulation...
Presentation
Silicifiers are among the most important organisms on planet Earth. Among them, diatoms play a key role in the trophic networks of the most productive coastal and open-ocean ecosystems, as well as in the biology-mediated transfer of CO 2 from the surface to the ocean interior. However, many gaps remain regarding their quantification at global scale...
Presentation
Full-text available
Presentation of first results from the 2015 Qikiqtarjuaq Ice Camp - Green Edge Project
Presentation
Full-text available
Presentation of first results from the Baffin Bay Expedition 2016 (NGCC Amundsen) - Green Edge Project
Article
Full-text available
The marine ecosystem of Kongsfjorden experiences large variations in primary productivity due to pronounced seasonal variations in sunlight, glacier melt, and ice cover. The objective of this study was to assess spatial and seasonal variability in the downward export of biogenic matter in Kongsfjorden. Short-term sediment traps were deployed for pe...
Article
We investigated the effects of iron (Fe) and copper (Cu) limitations on biogenic silica (bSiO2) dissolution kinetics of the marine diatom Pseudo-nitzschia delicatissima during a 3 week batch dissolution experiment. The dissolution of this species was faster during the first week than thereafter. Modeling results from four dissolution models and sca...
Article
Full-text available
Fragments of microplastics are readily incorporated into groups of microscopic algae, altering the rate at which the plastics move through seawater, a recent study has found. In laboratory tests, polystyrene microbeads, which usually sink to the bottom of seawater at a rate of 4 mm a day, sank at a rate of several hundreds of metres a day when part...
Article
Full-text available
Fragments of microplastics are readily incorporated into groups of microscopic algae, altering the rate at which the plastics move through seawater, a recent study has found. In laboratory tests, polystyrene microbeads, which usually sink to the bottom of seawater at a rate of 4 mm a day, sank at a rate of several hundreds of metres a day when part...
Article
Fragments of microplastics are readily incorporated into groups of microscopic algae, altering the rate at which the plastics move through seawater, a recent study has found. In laboratory tests, polystyrene microbeads, which usually sink to the bottom of seawater at a rate of 4 mm a day, sank at a rate of several hundreds of metres a day when part...
Article
Full-text available
Fragments of microplastics are readily incorporated into groups of microscopic algae, altering the rate at which the plastics move through seawater, a recent study has found. In laboratory tests, polystyrene microbeads, which usually sink to the bottom of seawater at a rate of 4 mm a day, sank at a rate of several hundreds of metres a day when part...
Article
Plastic debris are resistant to degradation, and therefore tend to accumulate in marine environment. Nevertheless recent estimations of plastic concentrations at the surface of the ocean were lower than expected leading the communities to seek new sinks. Among the different processes suggested we chose to focus on the transport of microplastics fro...
Article
Full-text available
Diatom aggregates contribute significantly to the vertical sinking flux of particulate matter in the ocean. These fragile structures form a specific microhabitat for the aggregated cells, but their internal chemical and physical characteristics remain largely unknown. Studies on the impact of aggregation on the Si cycle led to apparent inconsistenc...
Article
Full-text available
The recycling of biogenic silica (bSiO(2)) produced by diatoms is a vital process sustaining a significant fraction of primary production in the oceans. The efficiency with which bSiO(2) dissolves controls the availability of nutrient silicon in the water column, and modulates the export of organic carbon to the deep sea. Environmental conditions d...
Article
Full-text available
Interactions between carbon and silica in the diatom frustule play an important role in carbon export through their impact on diatom remineralization (carbon degradation and biogenic silica dissolution). To ameliorate model prediction of the fate of Si and organic matter during sedimentation, there is a need to first understand the origin and natur...
Article
Full-text available
Silicon (Si), in the form of dissolved silicate (DSi), is a key nutrient in marine and continental ecosystems. DSi is taken up by organisms to produce structural elements (e.g., shells and phytoliths) composed of amorphous biogenic silica (bSiO2). A global mass balance model of the biologically active part of the modern Si cycle is derived on the b...
Article
Full-text available
To elucidate the origin of the silicic acid (DSi) anomaly observed along the 4000 isobath on the Congo margin, we have established a benthic Si mass balance and performed direct measurements of biogenic silica (bSiO(2)) dissolution in the deep waters and in the sediments. Results strongly suggest that the anomaly originates from the sediments; the...
Article
Full-text available
A fully transient, 2-dimensional physical and biological model has been developed to quantify the seasonal cycle of silica in the estuaries-coastal zone continuum of the Bay of Brest (France). The numerical model includes an explicit representation of the benthic-pelagic coupling, which is stimulated by the increasing density of an invasive megaben...
Article
Full-text available
About a decade ago, the OPALEO community has evaluated the advantages and difficulties of using the mass accumulation rate of biogenic silica (opal MAR) in marine sediments, as a proxy for paleoproductivity (Ragueneau et al., 2000). On the one hand, diatoms play a major role in carbon export, biogenic silica is relatively well preserved compared to...
Article
Full-text available
While a relationship between ballast and carbon in sedimenting particles has been well-documented, the mechanistic basis of this interaction is still under debate. One hypothesis is that mineral ballast protects sinking organic matter from degradation. To test this idea, we undertook a laboratory experiment using the diatom Skeletonema marinoi to s...
Article
Full-text available
Knowing which fraction of a phytoplankton population is viable would often be helpful in answering ecological or physiological questions. However, viability stains (1) often do not function properly, especially with diatoms, (2) are rarely used, and (3) frequently appear to give ambiguous results. Here, we investigate the performance of the FDA via...
Article
Full-text available
The particles sinking out of the ocean's surface layer are made up of a mixture of living and dead algal cells, fecal pellets, and aggregates, while the parameters used to describe the behavior of biogenic silica (bSiO2) in today's models are experimentally determined on freely suspended diatoms (FC). In a simple advection-reaction model we combine...
Article
Settling particles were collected from the Ligurian Sea in the northwestern Mediterranean Sea in May 2003 and separated by elutriation into different settling velocity classes (.230, 115–230, 58–115, and ,58 m d21). Particles of the different classes were incubated for 5 d to study their biodegradability. Particulate opal content and organic compou...
Article
Full-text available
Because aggregated diatoms sink rapidly through the water column, leaving little time for dissolution, aggregation influences the balance between recycling of biogenic silica (bSiO2) and its sedimentation and preservation at the seafloor. Additionally, aggregation may directly impact dissolution rates of opal. Laboratory experiments were conducted...
Article
Full-text available
Despite recent progress in understanding the ocean's role in the global carbon cycle, we are not yet able to predict the response of ecosystems to climate change and feedbacks of the ocean onto atmospheric CO2. In particular, particle flux dynamics must be represented more faithfully in ocean models. We know that particulate organic carbon (POC) fl...
Article
Full-text available
Diatoms play a major role in carbon export from surface waters, but their role in the transport of carbon to the deep sea has been questioned by global analyses of sediment trap fluxes which suggest that organic carbon fluxes and transfer efficiencies through the mesopelagic are tightly correlated with CaCO3 (Klaas and Archer, 2002; François et al....
Article
Full-text available
Diatoms are key species that strongly participate to primary production and to carbon export out of the surface layer. During this PhD, the role of diatoms and the impact of aggregation on the biological pump were investigated using direct measurement of bSiO2 dissolution rates in aggregates and freely suspended diatoms during laboratory experiment...
Article
Full-text available
Biodeposition is a process that strongly affects physical, chemical and biological properties near the sediment–water interface, and mollusks have been shown to influence the cycling of many biogenic elements. In the Bay of Brest ecosystem, the invasive benthic suspension feeder Crepidula fornicata has been proliferating for 50years, and its influe...
Article
Full-text available
Les échanges entre le carbone de l'atmosphère et les autres réservoirs (océan, biosphère terrestre...) étaient équilibrés jusqu'à l'ère industrielle. Depuis 1850, les activités anthropiques telles que la déforestation, l'élevage intensif et surtout la combustion d'énergies fossiles émettent en grande quantité CO2 et CH4 dans l'atmosphère. L'équilib...

Network

Cited By

Projects

Projects (15)
Project
https://www-iuem.univ-brest.fr/lemar/projets-scientifiques/hippo/
Project
The objective of MOBYDICK is to study the links that exist between the biological pump of carbon and the food web structure. To address this issue MOBYDICK proposes a novel approach by considering the entire food web from microbes to top predators and by investigating the hitherto poorly studied relationships between biogeochemical fluxes and biodiversity. The dataset required to test the hypotheses proposed in MOBYDICK will be acquired during an oceanographic campaign off Kerguelen Island (Southern Ocean). In this well-documented area, 2 contrasted ecosystems ‘Low Biomass Low Export’ and ‘High Biomass Low Export’ coexist. MOBYDICK has gathered an international consortium to carry out a wide range of techniques for the determination of stocks, fluxes and biodiversity, which are rarely utilized simultaneously. The results will represent a milestone for fundamental knowledge, but they will also provide essential information for the sustainable management of these vulnerable ecosystems.
Archived project