Do human activities affect the picoplankton structure of the Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia)?

Marc Bouvy (1) , Christine Dupuy (2) , Marc Pagano (3) , Aude Barani (3) , Loic Charpy (3)

1 ECOLAG - Ecosystèmes lagunaires : organisation biologique et fonctionnement
2 LIENSs - LIttoral ENvironnement et Sociétés
3 MIO - Institut méditerranéen d'océanologie

The spatial variations of the picoplankton (photoautotrophic and heterotrophic microorganisms) in the Ahe atoll lagoon were studied in May and October 2008 to assess whether they were affected by human activities along the atoll. Spatial patterns were studied using 10 sampling stations chosen according to the location of the anthropogenic activities (pearl farming, harbor). Experiments were also carried out to determine whether bacterial growth, with or without predators, was limited by inorganic (N and P) substrates. The results showed that heterotrophic bacterioplankton abundance was superior to the photoautotrophic organisms, especially in May. Significant increases in bacterial abundance were observed in May after 24 hours incubation with +P and +N (but not in October). All samples complied with the quality levels for fecal indicator bacteria (FIB) defined by the European Union and there was no evidence that human sewage had any impact on picoplankton over the whole atoll.

Mots clés: Picoplankton; Enrichment experience; Human sewage; Atoll

Domaines: Milieux et Changements globaux; Ecosystèmes

Marc Bouvy, Christine Dupuy, Marc Pagano, Aude Barani, Loic Charpy. Do human activities affect the picoplankton structure of the Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia)?. Marine Pollution Bulletin, 2012, Ahe Atoll and Pearl Oyster Aquaculture in the Tuamotu Archipelago, 65 (10-12), pp.516-524. ⟨10.1016/j.marpolbul.2012.01.008⟩. ⟨hal-01420422⟩