The MARBEC unit and their partners carried out a study in the Ebrié lagoon in Ivory Coast, revealing the impact of wastewater on aquatic ecosystems. Human and livestock sewage is one of the major causes of excess nutrients, leading to the eutrophication of aquatic ecosystems and potentially to the emergence or spread of pathogenic viruses. This study aimed to investigate the composition and diversity of aquatic viromes in a highly anthropized lagoon, to identify the presence of pathogenic taxa and to explore their use as possible viral indicators of faecal contamination. For this, water and sediment samples were collected in the Ebrié Lagoon (Ivory Coast) at seven stations with contrasting levels of eutrophication.
https://www.ird.fr/les-virus-aquatiques-revelent-limpact-des-eaux-usees-nouvelles-cles-pour-la-sante-publique
Publication :
Andrianjakarivony, F.H., Bettarel, Y., Cecchi, P., Bouchard, S., Chase, E. & Desnues, C. 2023. Decoding the DNA and RNA viromes of a tropical urban lagoon. Environmental Microbiology, 25(11), 2368–2387. https://doi.org/10.1111/1462-2920.16463
– photo credit : IRD - Yvan Bettarel
A Franco-Brazilian team - including researchers from Marbec unit - has been studying the oceanographic determinants of the vertical structure of pelagic organisms in the south-western tropical Atlantic.
Ocean dynamics initiate the structure of nutrient income driving primary producers, and these, in turn, shape the distribution of subsequent trophic levels until the whole pelagic community reflects the physicochemical structure of the ocean. Despite the importance of bottom-up structuring in pelagic ecosystems, fine-scale studies of biophysical interactions along depth are scarce and challenging. To improve our understanding of such relationships, they analyzed the vertical structure of key oceanographic variables along with the distribution of acoustic biomass from multi-frequency acoustic data (38, 70, and 120 kHz) as a reference for pelagic fauna. In addition, they took advantage of species distribution databases collected at the same time to provide further interpretation. The study was performed in the Southwestern Tropical Atlantic of northeast Brazil in spring 2015 and autumn 2017 during the ABRACOS campaign.
https://www.ird.fr/lacoustique-revele-les-cles-de-la-repartition-verticale-de-la-biomasse-animale-marine
Publication :
Assuncao R., Lebourges Dhaussy Anne, da Silva A. C., Roudaut Gildas, Ariza A., Eduardo L. N., Queiroz S., Bertrand Arnaud. 2023. Fine-scale vertical relationships between environmental conditions and sound scattering layers in the Southwestern Tropical Atlantic. PLOS One, 18 (8) : e0284953. https://doi.org/10.1371/journal.pone.0284953
– Abraços 2 oceanographic campaign, Brazil.
photo credit : IRD - Arnaud Bertrand