International conférence on sargassum Thursday, October 24th, 2019 Day 1 - State of knowledge on Sargassum algae State of knowledge - biological, ecological and oceanographic data Fundamental knowledge about sargassum and related micro-organisms ---- Conférence Internationale sur les Sargasses Jeudi 24 octobre - Journée 1 État des lieux sur la connaissance des algues sargasses Table-ronde 1 Connaissance fondamentale des algues sargasses et des micro-organismes associés

1. Fundametal knowledge on Sargassum
and their associated microorganisms
LOPEZ Pascal Jean
24/ 10/ 2019

2. ECO3SAR : an interdiciplinary project combining knowledge, values ​​and applications
Agence De l’Environnement de la Maitrise de l’Energie (ADEME)
Malika René-Trouillefou (MCF, UA) *
Florence Menez (Chercheuse associée, UA) *
Anne Péné-Annette (MCF, UA) *
Franck Dolique (PR, UA)
Laboratoire Départemental d’Analyse de la Drôme (LDA 26)
Vincent Hervé (Postdoc, MPI – Allemagne)
Pascal Jean Lopez (DR, CNRS)
Damien Devault (Chercheur Associé, CNRS)
Josie Lambourdière (AI, CNRS)
Global ecology needs interdisciplinarity and integrated ways in order to bring new concepts and hopefully resolve issues
Holdex Environnement

3. ECO3SAR : an interdiciplinary project combining knowledge, values ​​and applications
Adapté de : Algues Vertes L’histoire Interdite, Belcourt
Adapté de : Algues Vertes L’histoire Interdite, Belcourt

4. ECO3SAR : Ecology, Ecotoxicology and Economy of Sargassum
WP 1 : Ecotoxicology of beached Sargassum from Martinique and Guadeloupe
WP 2 : Preliminary studies on contamination/decontamination processes
WP 3 : Diversity of the micro-organisms associated to Sargassum tides
WP 4 : Studies of sectors and social acceptances
Global ecology needs interdisciplinarity and integrated ways in order to bring new concepts and hopefully resolve issues
« pratiques, usages et représentations »
« l’action de l’homme sur la nature et la vision d’une nature perturbée et en évolution »

5. ECO3SAR : Ecology, Ecotoxicology and Economy of Sargassum
Global ecology needs interdisciplinarity and integrated ways in order to bring new concepts and hopefully resolve issues
WP 1 : Ecotoxicology of beached Sargassum from Martinique and Guadeloupe
WP 2 : Preliminary studies on contamination/decontamination processes
WP 3 : Diversity of the micro-organisms associated to Sargassum tides
WP 4 : Studies of sectors and social acceptances
« pratiques, usages et représentations »
« l’action de l’homme sur la nature et la vision d’une nature perturbée et en évolution »

6. Guadeloupe landscapes

7. Martinique landsapes

8. Campaign 1 : July-August 2018 Campaign 2 : February-March 2019
~ 34 sites
109 samples
~ 32 sites
118 samples
Sampling periods and sites
57 sites; 227 analyzes
• Sargassum floating in seawater or washed up on the beach
• “new” and “old” Sargassum
• A few storage sites
• A few “less coastal” sites (~ 27 km)

9. Lead (Pb)
Cadmium (Cd)
Nickel (Ni)
Cobalt (Co)
Zinc (Zn)
Cupper (Cu)
Chromium : Cr (III), Cr (VI)
Mercury: Hg, H3C-Hg+X-
Mineral arsenic: As (III), As (V)
Organic arsenic: Monomethylarsonic acid (MMA), Mimethylarsinic acid (DMA),
Arsenobetain (AsB), arsenocholine (AsC)
Dry weight
Mineral matter
Total organic matter (C)
Nitrogen (N)
Phosphorus (P)
Sulfur (S)
Metals, semimetals, and nonmetals coumpounds

10. Chlordécone (Kepone)
5b-hydro-chlordécone
chlordécol
Persistent Organic pollutants

11. [Arsenic] = 78 mg.kg-1 DM 0 < [CLD] < 1.2 mg.kg-1 DM
Sargassum can contain both oceanic and costal contaminants
North Atlantic Ocean : 0,64-1,94 µg.l-1 (Mlddelburg et al. 1988)
Atlantic Ocean : 0,41 – 1,57 µg.l-1 (Braman and Foreback, 1973)
On the same order of magnitude than estuarine and fluvial waters
Virgin soils varies from 0.1 to 40 µg.kg-1
Continental crust of the earth: 1.5–2 µg.kg-1

12. ECO3SAR : Ecology, Ecotoxicology and Economy of Sargassum
Global ecology needs interdisciplinarity and integrated ways in order to bring new concepts and hopefully resolve issues
WP 1 : Ecotoxicology of beached Sargassum from Martinique and Guadeloupe
WP 2 : Preliminary studies on contamination/decontamination processes
WP 3 : Diversity of the micro-organisms associated to Sargassum tides
WP 4 : Studies of sectors and social acceptances
« pratiques, usages et représentations »
« l’action de l’homme sur la nature et la vision d’une nature perturbée et en évolution »

13. Algae microbiome
Symbiotic bacteria
Pathogenicity Defense
Oxygen, Organic
compounds
Anchorage,
Protection
Carbon dioxide, Fixed
nitrogen, minerals and
growth
Detoxification, life cycle,
Anti-fouling

14. Metabarcoding of the 16S rDNA*
100 samples: Seaweeds and Surrounding seawater
0%
50%
100%Diversity: ~ 22,200 OTUs
Relative abundance: 2,849,100 reads
0%
50%
100%
Guadeloupe Martinique
Guadeloupe Martinique
0%
4%
8%
12%
0
400
800
1200
BacteroidetesCyanobacteria
Firmicutes Other Bacteria
Planctomycetes
Proteobacteria
* Unpublished data

15. SargassumSeawater
0.40.20.0-0.2
-0.4
-0.2
0.0
0.2
Axis.1 [18.9%]
Axis.2[14.6%]
R2=0.09, P<0.001
Regional, substrat and medium specific bacterial diversity *
Region
38
89
110
1513
21
2
Substrat
Medium
Respiration_of_sulfur_compounds 404
Fermentation 314
Human_pathogens_all 142
Intracellular_parasites 491
Functional categories:
* Unpublished data

16. Thank you
Algues
la relance ici se fait
par le vent qui d’Afrique vient
par la poussière d’alizée
par la vertu de l’écume
et la force de la terre
nu
l’essentiel est de sentir nu
de penser nu
la poussière d’alizé
la vertu de l’écume
et la force de la terre
la relance ici se fait par l’influx
plus encore que par l’afflux
la relance
se fait
algue laminaire
Aimé Césaire
« Global and local scale »
« Not one but many/various Sargassum ecosystems »