Back to Search
Start Over
Do microbial planktonic communities reflect the ecological changes of Glorieuses coral reefs (Iles Eparses, Western Indian Ocean)?
- Source :
- Marine Pollution Bulletin (0025-326X) (Elsevier BV), 2022-01, Vol. 174, P. 113218 (17p.), Marine Pollution Bulletin, Marine Pollution Bulletin, 2022, 174, pp.113218. ⟨10.1016/j.marpolbul.2021.113218⟩
- Publication Year :
- 2022
- Publisher :
- Elsevier BV, 2022.
-
Abstract
- WOS:000737215300006; International audience; Ecological baselines for the structure and functioning of ecosystems in the absence of human activity can provide essential information on their health status. The Glorieuses islands are located in the Western Indian Ocean (WIO) and can be considered as "pristine" ecosystems that have not been subjected to anthropogenic pressure. Their nutrient context and the microbial assemblages were assessed by determining the abundance of heterotrophic prokaryotes (archaea and bacteria), picocyanobacteria, picoeukaryotes, microphytoplankton and protozooplankton communities in five stations, during two contrasted periods (November 2015 and May 2016). Chlorophyll-a concentrations were always under 1 mu g/L and associated to very low levels in orthophosphates, nitrate and dissolved organic carbon, revealing an ultra-oligotrophic status for the Glorieuses waters. Picocyanobacteria confirmed the ultra-oligotrophic status with a predominance of Synechococcus. Zeaxanthin associated with the presence of picocyanobacteria represented the major pigment in both surveys. Three indices of diversity (species richness, Shannon and Pielou indexes) from microscopy observations highlighted the difference of diversity in microphytoplankton between the surveys. A focus on a 16S metabarcoding approach showed a high dominance of picocyanobacteria, Alpha- and Gammaproteobacteria, regardless of station or period. Multivariate analyses (co-inertia analyses) revealed a strong variability of ecological conditions between the two periods, with (i) high nutrient concentrations and heterotrophic nanoflagellate abundance in November 2015, and (ii) high heterotrophic prokaryote and picoeukaryote abundance in May 2016. The impact of a category 5 tropical cyclone (Fantala) on the regional zone in April 2016 is also advanced to explain these contrasted situations. Relative importance of top-down factors between bacterial and heterotrophic nanoflagellates was observed in November 2015 with an active microbial food web. All the results indicate that three microbial indexes potentially can be considered to assess the ecological change in Glorieuses marine waters.
- Subjects :
- 0106 biological sciences
[SDE.MCG]Environmental Sciences/Global Changes
Ecological changes
Microorganisms
atoll
picoplankton
Aquatic Science
Oceanography
Dissolved Organic Matter
01 natural sciences
mozambique channel
diversity
03 medical and health sciences
senegal river
[SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems
cyclonic eddy
Humans
14. Life underwater
mediterranean sea
Indian Ocean
030304 developmental biology
Synechococcus
0303 health sciences
Coral Reefs
010604 marine biology & hydrobiology
Anthropogenic Effects
Microbiota
15. Life on land
Plankton
Pollution
Cyclone
tuamotu archipelago
13. Climate action
phytoplankton communities
flow-cytometry
[SDE.BE]Environmental Sciences/Biodiversity and Ecology
Pristine ecosystem
Subjects
Details
- Language :
- English
- ISSN :
- 0025326X
- Database :
- OpenAIRE
- Journal :
- Marine Pollution Bulletin (0025-326X) (Elsevier BV), 2022-01, Vol. 174, P. 113218 (17p.), Marine Pollution Bulletin, Marine Pollution Bulletin, 2022, 174, pp.113218. ⟨10.1016/j.marpolbul.2021.113218⟩
- Accession number :
- edsair.doi.dedup.....b4f6d05d36773b8541be603c2420a3f0