Do human activities affect the picoplankton structure of the Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia)?
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 h 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.
UMR 5119, ECOSYM, Ecologie des Systèmes Marins Côtiers (UM2, CNRS, IRD, Ifremer, UM1), Université Montpellier 2, Place Eugène Bataillon, Case 093, 34095 Montpellier Cedex 5, France. marc.bouvy@ird.fr
Marc
M
Bouvy
Christine
C
Dupuy
Marc
M
Pagano
Aude
A
Barani
Loic
L
Charpy
D001419:Bacteria / Q000145:classification / Q000254:growth & development; D004784:Environmental Monitoring; D006801:Humans; D010933:Plankton / Q000145:classification / Q000254:growth & development*; D011114:Polynesia; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology; D012722:Sewage / Q000032:analysis / Q000706:statistics & numerical data; D014876:Water Pollution / Q000032:analysis* / Q000706:statistics & numerical data
D012722:Sewage