Emma MichaudFrench National Centre for Scientific Research | CNRS · Laboratoire des Sciences de l'Environnement Marin
Emma Michaud
PhD University of Aix Marseille (France) & University of Quebec at Rimouski (Canada)
About
45
Publications
12,779
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1,197
Citations
Citations since 2017
Introduction
I am interested by the effects of benthic biodiversity changes and its bioturbation activities, on the biogeochemical functioning of coastal ecosystems storing large amounts of sedimentary carbon and under influence of various natural and anthropogenic forcings (Mangroves, Estuaries, Arctic fjords). I work in the field and/or in controlled conditions by using many complementary methodologies and approaches (2D-3D benthic imagery, remote sensing, biogeochemistry, functional ecology...).
Additional affiliations
April 2007 - December 2008
Education
January 2003 - October 2006
Field of study
- functional ecology, sediment biogeochemistry, bioturbation
September 2001 - December 2002
Publications
Publications (45)
The Echinoderes coulli-group is characterized by the presence of an enlarged nephridiopore composed of two regions apparently related to increase the osmoregulation efficiency. Representatives of this group are often intertidal species living in habitats with daily salinity changes, including mangroves. In the present study, two new species potenti...
The Kinorhyncha community inhabiting a mangrove forest impacted by domestic sewage discharges in the past has been explored in Mayotte Archipelago (southwestern Indian Ocean). Two new species of Echinoderes, which putatively belong to the Echinoderes coulli-group, are described: E. cyaneafictus sp. nov. And E. parthenope sp. nov. Echinoderes cyanea...
The sustainability of mangrove ecosystems requires a knowledge of their spatiotemporal variability as a function of regional properties. The unique coastal ecosystems of the mangrove belt along the coast of the Guianas in South America are influenced by cycles of a massive accretion of mud supplied by the Amazon River and wave induced erosion. This...
Hyper-DRELIO (Hyperspectral DRone for Environmental and LIttoral Observations) is a custom, mini-UAV (unmanned aerial vehicle) platform (<20 kg), equipped with a light push broom hyperspectral sensor combined with a navigation module measuring position and orientation. Because of the particularities of UAV surveys (low flight altitude, small spatia...
The impact of bioturbation on the geochemistry of aquatic sediments is known to depend on the benthic infauna species that are present. However, burrowing and activity patterns of each species may also change during the different stages of a life cycle. In this study, we examined the effects of four size classes of the polychaete Nephtys incisa on...
The microbial communities inhabiting the Atlantic-East Pacific (AEP) mangroves have been poorly studied, and mostly comprise chronically polluted mangroves. In this study, we characterized changes in the structure and diversity of microbial communities of mangroves along the urban-to-rural gradient of the Cayenne estuary (French Guiana, South Ameri...
Particle mixing and irrigation of the seabed by benthic fauna (bioturbation) have major impacts on ecosystem functions such as remineralization of organic matter and sediment-water exchange. As a tribute to Prof. Gaston Desrosiers by the Nereis Park association, eighteen laboratories carried out a collaborative experiment to acquire a global snapsh...
Particle mixing and irrigation of the seabed by benthic fauna (bioturbation) have major impacts on ecosystem functions such as remineralization of organic matter and sediment-water exchange. As a tribute to Prof. Gaston Desrosiers by the Nereis Park association, eighteen laboratories carried out a collaborative experiment to acquire a global snapsh...
Bioindicators assess the mangroves ecological state according to the types of pressuresbut they differ with the ecosystem’s specificities. We investigated benthic meiofauna diversity andstructure within the low human-impacted mangroves in French Guiana (South America) in responseto sediment variables with various distances to the main city. Contami...
European Water Framework Directive is enforced in five tropical French Oversea Territories where mangroves are present. Developing bioindication tools to support the ecosystem-based management approach of the Directive is needed. A series of expert workshops was organized and led to the proposal of a strategy and of an applied research program to d...
The iconic picture of Arctic marine ecosystems shows an intense pulse of biological productivity around the spring bloom that is sustained while fresh organic matter (OM) is available, after which ecosystem activity declines to basal levels in autumn and winter. We investigated seasonality in benthic biogeochemical cycling at three stations in a hi...
There is growing evidence that a substantial fraction of the dissolved organic and inorganic carbon (DOC and DIC) and particulate organic carbon (POC) can be exported from mangroves to the ocean. Yet, our understanding of C fluxes in mangrove forests is limited to only few regional studies that exclude the world’s longest sediment dispersal system...
Epibiosis is a common phenomenon in marine systems. In marine environments, ciliates are among the most common organisms adopting an epibiotic habitus and nematodes have been frequently reported as their basibionts. In the present study, we report several new records of peritrich and suctorian ciliates-nematode association worldwide: from a deep-se...
Characterisation of the ecosystem functioning of mudflats requires insight on the morphology and facies of these coastal features, but also on biological processes that influence mudflat geomorphology, such as crab bioturbation and the formation of benthic biofilms, as well as their heterogeneity at cm or less scales. Insight into this fine scale o...
The aim of this study was to assess bioturbation rates in relation to macrozoobenthos and environmental variables in the Svalbard fjords, Barents Sea and Nansen Basin during spring to summer transition. The results showed differences in benthic community structure across sampled area in relation to sediment type and phytopigment content. Fjords, Ba...
Title: The sources and distribution of carbon (DOC, POC, DIC) in a mangrove dominated estuary (French Guiana, South America)
TabS1: List of aerial and satellite images used to derive theoretical mangrove ages
TabS2: Values of physico-chemical water parameters measured during 2013-2015 in the different stations
Mangrove forests are highly productive coastal ecosystems that significantly influence global carbon cycling. This study characterized the sources of dissolved organic carbon (DOC), particulate organic carbon (POC) and dissolved inorganic carbon (DIC) and the processes affecting their distributions in a mangrove-influenced estuary located in French...
Les palétuviers, ces arbres aux racines aériennes étonnantes et captivantes, peuplent les mangroves. Mais à leurs pieds, dans les eaux circulantes et le sédiment vaseux, tantôt immergées tantôt asséchées, habitent une faune et une microflore tout aussi fabuleuses. Ainsi, le petit monde invisible des microorganismes recycle la litière ou s’associe e...
This study aims to qualify, quantify, and compare the sediment reworking rates induced by the meso- (0.25–1 mm) and macro-infauna (>1 mm) along a mangrove growth gradient in the sedimentary dynamics of the French Guiana coast. The characterization of the role of small-infauna bioturbation in mangroves is new despite their known numerical dominance...
2017-410
Mangroves are among the most sensitive marine ecosystems to oil pollution due both to the sensitivity of mangroves species and to the high persistence of hydrocarbons in these environments. Despite their ecological and socio-economic value, the potential effects of an oil spill on French Guiana mangroves remain so far unknown. Yet, there i...
Spatio-temporal distribution, mixing and sources of DOC, POC and DIC were studied along the mangrove dominated estuarine waters under the Amazonian influence in FG. Our first results from fieldwork in Guianese mangroves during dry and wet seasons of 2015 showed that “terrestrial” sources (litter, benthic algae) mainly contributed to the estuarine O...
Photogrammetry is an old remote sensing technique that has undergone significant new developments related to the emergence of new computer vision algorithms, notably the workflow technique called Structure-from-Motion (SfM photogrammetry). These innovations facilitate the utilization of this technique by non-specialists. SfM photogrammetry now enab...
The current understanding of Arctic ecosystems is deeply rooted in the classical view of a bottom-up controlled system with strong physical forcing and seasonality in primary-production regimes. Consequently, the Arctic polar night is commonly disregarded as a time of year when biological activities are reduced to a minimum due to a reduced food su...
Ferrous iron, Fe(II), is abundant in a wide variety of aquatic environments where suboxic and anoxic conditions are developed. In marine sediments, it is typically a product of reduction reactions involving use of Fe(III) as an electron acceptor by microbes during organic matter remineralization, or it is derived from abiotic reactions of Fe(III) w...
In Arctic areas where benthic primary production does not occur or is not sufficient, the benthos depends on episodic events of food inputs from overlying waters, in particular spring ice algae and phytoplankton blooms. Climate change is expected to lead to earlier ice melts, and subsequently to earlier spring blooms and food inputs to the benthos....
This study aims to investigate the role of spatial and temporal physical, biological and biogeochemical gradients on sediment biogeochemistry along a macrotidal and Si-rich estuary. Scanning and biogeochemical analyses were performed in the inner, mid and outer Aulne Estuary (France) at four seasons. The inner estuary shows high diagenetic activity...
The coupling between biogenic reworking activity and reactive organic matter patterns within deposits is poorly understood and often ignored. In this study, we examined how common experimental treatments of sediment affect the burrowing behavior of the polychaete Nephtys incisa and how these effects may interact with reactive organic matter distrib...
We examined how interactions among the three dominant species of the Macoma balthica community in the St-Lawrence estuary influence net biogeochemical fluxes and the composition of the sedimentary bacterial community. We manipulated the biodiversity of the community via combinations of Macoma balthica, Mya arenaria, and Nereis virens in sediment mi...
In order to compare and quantify sediment reworking activities by different species/functional groups of macrofauna, a laboratory experiment was carried out with species from the Gullmarsfjord (Western Sweden). Monospecific communities of Amphiura filiformis, Echinocardium cordatum, Scalibregma inflatum and Abra nitida were introduced in experiment...
We have examined the effects of individual members of the two dominant functional groups of the Macoma balthica community on fluxes of nutrients and dissolved organic carbon between sediment and overlying water. The biodiffusers M. balthica and Mya arenaria and the gallery-diffuser Nereis virens were added to microcosms containing sieved tidal flat...
The Macoma balthica community, which is widely distributed in intertidal soft sediments bordering the north Atlantic, is dominated by two functional groups with different sediment mixing modes: the biodiffusers M. balthica and Mya arenaria and the gallery-diffuser Nereis virens. To compare the effects of these two groups on sediment oxygen uptake r...
At the water–sediment interface of aquatic ecosystems, the presence of biogenic structures produced by benthic invertebrates strongly affects biogeochemical processes. The quantification of these structures and the assessment of the vertical distribution of fauna are essential for determining the impact of communities in sediments. In the present s...
In the upper layer of the sediment column, organic matter recycling is greatly influenced by bioturbation. However, there are many physical changes in the nature of the sediment that may disturb benthic communities and create a biogeochemical imbalance. Following a very heavy rainfall between 26 and 29 July 1996, an intense flash flood in the Sague...
Historically, advances in our knowledge of benthic community structure and functioning have necessarily relied upon destructive sampling devices (grabs, cores, anchor dredges, etc.) that lose valuable contextual information in the process of sampling. In the last 40 years, instrumentation capable of measuring dynamic events and/or processes within...
Projects
Project (1)
International thematic school on "BIOTURBATION" (6th Nereis Park International Conference)
“Bioturbation in the past and present: from terrestrial to marine ecosystems”
22-26 Août 2022, Logonna Daoulas - France
https://www-iuem.univ-brest.fr/nereis-park-vi/?lang=en
Deadline for abstract submission and pre-registration: 31 March 2022
FREE FOR CNRS STAFF but pre-registration mandatory (abstract submission)
The aim of this event is to bring together the international scientific community of researchers working on the mechanisms of bioturbation in marine, freshwater and terrestrial environments, at all latitudes (polar, tropical, temperate), and taking different time scales into account (from Precambrian to present). This event is in the framework of the international Nereis Park association gathering all scientists working on Bioturbation (http://www.nereispark.org/). This 6th edition proposes an international thematic school on Bioturbation with conferences and high-level training. It will allow promoting scientifical exchanges and giving scientists and students the latest conceptual and technological advances around the bioturbation processes through conferences and posters sessions, small workshops, debates, practical studies. The contributions for this event could be submitted for publications in a special issue on bioturbation.
