Nicolas Djeghri

Nicolas Djeghri
Marine Biological Association of the UK | MBA · CPR survey

PhD

About

12
Publications
3,805
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67
Citations
Introduction
I just finished my PhD on zooxanthellate jellyfishes (and by the way, I'm looking for a PostDoc!). Stay tuned though as not all is published yet, there is more to come using stable isotopes and fatty acids!
Additional affiliations
September 2017 - present
Université de Bretagne Occidentale
Position
  • PhD Student
Description
  • Teaching in Ecology and Animal Biology, mainly to undergraduate students
October 2016 - March 2020
Université de Bretagne Occidentale
Position
  • PhD Student
Description
  • Zooxanthellate jellyfish ecology; ontogenic and environmental variations of the role of the symbiosis
January 2016 - June 2016
Plymouth Marine Laboratory
Position
  • Master's Student
Description
  • Copepod feeding ecology
Education
September 2014 - June 2016

Publications

Publications (12)
Article
The trophic ecology of mixotrophic, zooxanthellate jellyfishes potentially spans a wide spectrum between autotrophy and heterotrophy. However, their degree of trophic plasticity along this spectrum is not well known. To better characterize their trophic ecology, we sampled the zooxanthellate medusa Mastigias papua in contrasting environments and si...
Article
Full-text available
Mixotrophic organisms are increasingly recognized as important components of ecosystems, but the factors controlling their nutrition pathways (in particular their autotrophy–heterotrophy balance) are little known. Both autotrophy and heterotrophy are expected to respond to density-dependent mechanisms but not necessarily in the same direction and/o...
Thesis
Full-text available
Whereas most jellyfishes are strictly heterotrophic organisms, some of them undergo a photosymbiosis with autotrophic Dinophyceae (“zooxanthellae”). These zooxanthellate jellyfishes, as holobionts, are mixotrophic deriving nutrition from both predation and photosynthesis. However, the relative importance of autotrophic and heterotrophic nutrition c...
Article
Some jellyfish host zooxanthellae in their tissues (mostly from the family Symbiodiniaceae; Dinophyceae) and supplement their heterotrophic nutrition with their symbiont's photosynthates. The mixotrophy of zooxanthellate jellyfishes (as holobionts) renders the study of their nutrition, growth, and population dynamics complicated. Here, we used an e...
Poster
Full-text available
We investigated the nutritional plasticity of the zooxanthellate jellyfish Mastigias papua in Palau's marine lake and demonstrate that its nutrition can go from pure heterotrophy to dominant autotrophy. This is, to our knowledge the first field-based characterization of the nutritional plasticity of a zooxanthellate jellyfish. The important nutriti...
Presentation
Full-text available
We present a summary of the knowledge on zooxanthellate jellyfishes. This presentation is build on our published paper: Djeghri N, Pondaven P, Stibor H, Dawson MN (2019) Review of the diversity, traits, and ecology of zooxanthellate jellyfishes. Mar Biol 166:147
Article
Full-text available
Many marine organisms form photosymbioses with zooxanthellae, but some, such as the medusozoans, are less well known. Here, we summarize the current knowledge on the diversity of zooxanthellate jellyfishes, to identify key traits of the holobionts, and to examine the impact of these traits on their ecology. Photosymbiosis with zooxanthellae origina...
Presentation
Full-text available
Zooxanthellate jellyfishes rely generally on two contrasted sources of nutrition: predation, and photosynthesis. When studying these organisms, one of the primary questions is to understand how the two sources are balanced relative to each other. We present experimental evidence that isotopic signatures and C:N ratios of zooxanthellate jellyfishes...
Article
There has been an upsurge of interest in trait-based approaches to zooplankton, modelling the seasonal changes in the feeding modes of zooplankton in relation to phytoplankton traits such as size or motility. We examined this link at two English Channel plankton monitoring sites south of Plymouth (L4 and E1). At L4 there was a general transition fr...
Article
The Plymouth L4 time plankton series in the Western English Channel is a textbook example of a shallow, stratifying shelf sea system. Over its 30 yr of weekly sampling, this site has provided a diverse and contrasting suite of numerical and conceptual models of plankton bloom formation, phenology, and seasonal succession. The most recent of these p...
Article
There has been an upsurge of interest in trait-based approaches to zooplankton, modelling the seasonal changes in the feeding modes of zooplankton in relation to phytoplankton traits such as size or motility. We examined this link at two English Channel plankton monitoring sites south of Plymouth (L4 and E1). At L4 there was a general transition fr...
Research
Full-text available
Master 2 Thesis. Internship supervised by Angus Atkinson at the Plymouth Marine Laboratory (UK) in order to obtain the diploma of "Océanographie spécialité Biologie Ecologie Marine" of the Aix-Marseille University (FR)

Network

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Projects

Projects (2)
Project
Impressively, eight extensive volumes of reviews about most of the scyphozoan taxa were published by Max Egon Thiel (1898-1979) between 1936 and 1977 (interrupted by WWII, c. 1300 printed pages). The final edition on Rhizostomeae did not make it to the printer; however, the family saved an unpublished manuscript. As it is still considered worth publishing and will complete the series, an international group of jellyfish scientists are cooperating to complement this final volume with a review edition on the most recent “Half a century of Rhizostomeae Research”. More than 20 collaborators are lending their expertise to produce this special volume, edited by André Morandini, Sabine Holst, and Götz B. Reinicke.
Project
This is the subject of a three year Phd sarted in November 2016 in the Brest University (France). We aim to gain a better understanding of the ecology of zooxanthellate jellyfish. We are particularly interested in the way they use different ressources (light, food and nutrients) and how the balance and availability of theses could impact their life cycle (budding, strobilation, growth...).