A5052003147- Marine and coastal ecosystems
- Microbial Community Ecology and Physiology
- Methane Hydrates and Related Phenomena
- Marine Biology and Ecology Research
- Magnetic properties of thin films
- Magneto-Optical Properties and Applications
- Arctic and Antarctic ice dynamics
- Geology and Paleoclimatology Research
- Oceanographic and Atmospheric Processes
- Genomics and Phylogenetic Studies
- Isotope Analysis in Ecology
- Environmental DNA in Biodiversity Studies
- Ocean Acidification Effects and Responses
- Phase-change materials and chalcogenides
- Polar Research and Ecology
- Surface and Thin Film Phenomena
- Magnetic Properties and Applications
- Atmospheric and Environmental Gas Dynamics
- Magnetic Properties and Synthesis of Ferrites
- Photonic and Optical Devices
- Marine and environmental studies
- Optical Network Technologies
- Surface Roughness and Optical Measurements
- Theoretical and Computational Physics
- Protist diversity and phylogeny
Havstovan
2018-2024
Sorbonne Université
2011-2023
Centre National de la Recherche Scientifique
2009-2023
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
2014-2023
Observatoire Océanologique de Banyuls-sur-Mer
2009-2023
Laboratoire d'Océanographie Microbienne
2013-2023
ORCID
2020
University of Liverpool
2017
Université Paris Cité
2014
Laboratoire d'Ecogéochimie des Environnements Benthiques
2013
Marine Archaea are important players among microbial plankton and significantly contribute to biogeochemical cycles, but details regarding their community structure long-term seasonal activity dynamics remain largely unexplored. In this study, we monitored the interannual archaeal composition of abundant rare biospheres in northwestern Mediterranean Sea surface waters by pyrosequencing 16S rDNA rRNA. A detailed analysis biosphere showed that was composed three distinct fractions. One...
Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of marine microbial biodiversity and function world's oceans. It is simultaneous global mega-sequencing campaign aiming generate largest standardized data set in single day. This will be achievable only through coordinated efforts an Consortium, supportive partnerships networks between sites. commentary outlines establishment, aims Consortium...
Microbial communities of the Arctic Ocean are poorly characterized in comparison to other aquatic environments as their horizontal, vertical, and temporal turnover. Yet, recent studies showed that marine ecosystem harbors unique microbial community members adapted harsh environmental conditions, such near-freezing temperatures extreme seasonality. The gene for small ribosomal subunit (16S rRNA) is commonly used study taxonomic composition natural environment. Several primer sets this marker...
Abstract Environmental DNA (eDNA) has emerged as a powerful approach for studying marine fisheries and the potential to negate some of drawbacks trawl surveys. However, successful applications in oceanic waters have date been largely focused on qualitative descriptions species inventories. Here we conducted quantitative eDNA survey Atlantic cod ( Gadus morhua ) compared it with results obtained from standardized demersal survey. Detection originating was highly concordant (80%) catches. We...
Abstract The North Atlantic is characterized by diatom-dominated spring blooms that results in significant transfer of carbon to higher trophic levels and the deep ocean. These are terminated limiting silicate concentrations summer. Numerous regional studies have demonstrated phytoplankton community shifts lightly-silicified diatoms non-silicifying plankton at onset limitation. However, understand basin-scale patterns ecosystem climate dynamics, nutrient inventories must be examined over...
Reliable statements about variability and change in marine ecosystems their underlying causes are needed to report on status guide management. Here we use the Framework Ocean Observing (FOO) begin developing ecosystem Essential Variables (eEOVs) for Southern System (SOOS). An eEOV is a defined biological or ecological quantity, which derived from field observations, contributes significantly assessments of ecosystems. Here, concerned with estimating trends properties, attribution causes,...
Abstract A seven-year oceanographic time series in NW Mediterranean surface waters was combined with pyrosequencing of ribosomal RNA (16S rRNA) and gene copies rDNA) to examine the environmental controls on SAR11 ecotype dynamics potential activity. diversity exhibited pronounced seasonal cycles remarkably similar total bacterial diversity. The timing maxima across narrow broad phylogenetic clades strongly associated deep winter mixing. Diversity minima were periods stratification that low...
The ocean moderates the world's climate through absorption of heat and carbon, but how much carbon will continue to absorb remains unknown. North Atlantic Ocean west (Baffin Bay/Labrador Sea) east (Fram Strait/Greenland Greenland features most intense anthropogenic globally; biological pump (BCP) contributes substantially. As Arctic sea-ice melts, BCP changes, impacting global other critical attributes (e.g. biodiversity). Full understanding requires year-round observations across a range...
From a synthesis of recent oceanic observations and paleo‐data it is evident that certain species giant diatoms including Rhizosolenia spp. Thalassiothrix Ethmodiscus rex may become concentrated at frontal zones subsequently form episodes mass flux to the sediment. Within nutrient bearing waters advecting towards boundaries, these are generally not dominant, but they appear selectively segregated fronts, thus dominate export flux. Ancient diatom mat deposits in eastern equatorial Pacific...
Southern Ocean Island systems sustain phytoplankton blooms induced by natural iron fertilization that are important for the uptake of atmospheric carbon dioxide and serve as analogues past future climate change. We present data on diatom flux assemblages biogeochemical properties sinking particles to explain enhanced particulate organic (POC) export fluxes observed in response supply Crozet Islands region (CROZeX). Moored deep‐ocean sediment traps (>2000 m) were located beneath a...
Environmental DNA (eDNA) can be defined as the pool recovered from an environmental sample that includes both extracellular and intracellular DNA. There has been a significant increase in number of recent studies have demonstrated possibility to detect macroorganisms using eDNA. Despite enormous potential eDNA serve biomonitoring conservation tool aquatic systems, there remain some important limitations concerning its application. One factor is variable persistence over natural gradients,...
Climate models project that the Arctic Ocean may experience ice-free summers already in second half of this century. This have severe repercussions on phytoplankton bloom dynamics and associated cycling carbon surface waters. We currently lack baseline knowledge seasonal microbial communities, which is needed order to better estimate effects such changes ecosystem functioning. Here we present a comparative study polar summer communities (eastern) ice-covered (western) hydrographic regimes at...
The Arctic Ocean features extreme seasonal differences in daylight, temperature, ice cover, and mixed layer depth. However, the diversity ecology of microbes across these contrasting environmental conditions remain enigmatic. Here, using autonomous samplers sensors deployed at two mooring sites, we portray an annual cycle microbial diversity, nutrient concentrations physical oceanography major hydrographic regimes Fram Strait. ice-free West Spitsbergen Current displayed a marked separation...
Arctic Ocean sea ice cover is shrinking due to warming. Long-term sediment trap data shows higher export efficiency of particulate organic carbon in regions with seasonal compared without ice. To investigate this sea-ice enhanced export, we how different early summer phytoplankton communities seasonally ice-free and ice-covered the Fram Strait affect vertical dispersal microbes. In situ collected aggregates revealed two-fold diatom-rich regions, Phaeocystis region. Using microbial source...
Very large pulses of particulate organic matter intermittently sink to the deep waters open ocean in Northeast Atlantic. These pulses, measured by moored sediment traps since 1989, can contribute up 60% flux 3000 m a particular year and are thus major cause variability carbon sequestration from atmosphere region. Pulses occur late summer characterized material that is very rich but with low concentrations biominerals opal calcite. A number independent lines evidence have been examined...
Abstract. The biological composition of the material exported to a moored sediment trap located under winter mixed layer naturally fertilized Kerguelen Plateau in Southern Ocean was studied over an annual cycle. Despite iron availability spring, particulate organic carbon (POC) export (98.2 mmol m−2) at 289 m low, but biogenic silica significant (114 m−2). This feature related abundance empty diatom cells and ratio full exerted first-order control BSi : POC stoichiometry pump. Chaetoceros...