Nutrient and microbial dynamics in eutrophying shrimp ponds affected or unaffected by vibriosis.
A field survey was conducted on two intensive shrimp farms using similar technical practices: one (DF) historically affected by a vibriosis, the other (HC) in which the pathogen has been observed although no mortality event has occurred. Because historical data suggest that eutrophication process may directly or indirectly play a role in the disease outbreak, we focussed our research on its dynamics. A higher variability of the phytoplanktonic compartment linked to an imbalance in the molar N:P ratio was observed in farm DF compared to farm HC, implying a modification on the linkage between the bacteria and phytoplankton compartments at DF. The beginning of the mortality outbreak at DF followed a shift from pico- to nanophytoplankton. The organic matter mineralization process at the water-sediment interface may explain the disturbance observed in the water column during eutrophication. The consequences of this disturbance on shrimps' health status and pathogen ecology are discussed.
Lemonnier
Hugues
H
IFREMER, LEAD, BP 2059, 98846 Nouméa cedex, New Caledonia. hugues.lemonnier@ifremer.fr
Courties
Claude
C
Mugnier
Chantal
C
Torréton
Jean-Pascal
JP
Herbland
Alain
A
D000818:Animals; D017756:Aquaculture; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D017753:Ecosystem; D004784:Environmental Monitoring; D005068:Eutrophication; D019015:Geologic Sediments / Q000737:chemistry; D056265:Microbial Interactions; D009584:Nitrogen / Q000032:analysis; D033561:Penaeidae / Q000382:microbiology*; D010758:Phosphorus / Q000032:analysis; D010839:Phytoplankton / Q000254:growth & development; D012623:Seawater / Q000737:chemistry; D014733:Vibrio / Q000254:growth & development / Q000472:pathogenicity
D002734:Chlorophyll; D010758:Phosphorus; D009584:Nitrogen; D000077194:Chlorophyll A