INVESTIGADORES
LARA Ruben Jose
congresos y reuniones científicas
Título:
Impacts of cyclone mediated changes in estuarine environment on Vibrio populations in the coastal region of the Bay of Bengal
Autor/es:
NEOGI, S.B.; YAMASAKI, S.; ALAM, M.; LARA, R.J.
Lugar:
Savar
Reunión:
Conferencia; 27th Annual Conference of the Bangladesh Society of Microbiologists (BSM) Jahangirnagar University at Savar,; 2013
Institución organizadora:
Bangladesh Society of Microbiologists
Resumen:
Global warming and climate change may intensify cyclone events and influence pathogenic aquatic bacterial populations in the coastal zone. Vibrios are bacteria of marine and estuarine origin that can cause diseases in human (e.g., cholera, gastroenteritis, septicemia, etc.) and aquatic organisms like fish, shrimp, corals, etc. Little is known about the influence of tropical storm on estuarine Vibrio dynamics. The impacts of storm-driven changes in the salinity and other parameters of estuarine environment along with the changes cultivable Vibrio counts (CVC) in various sites (n=14) of Karnaphuli estuary, Bangladesh, were compared before and after a strong cyclone.In the hydrologically stable pre-cyclone situation, CVC were higher (~103 cfu/ml) at higher saline zone near estuary?s mouth (salinity 20-15 parts per thousand, ppt) and declined towards the inner sector, more steeply at salinities <5 ppt. After the cyclone the higher saline zone intruded landwards along with increased suspended particulate matter (SPM) and turbidity. Although there was no major change in the level of inorganic nutrients (e.g., nitrate), a significant rise in the concentration of SPM, particulate organic carbon and chitin was observed. CVC showed more than 10-fold increase after the cyclone, likely due to higher loads of organic matter and chitin accumulated in the suspended sediments. CVC and salinity correlated significantly at salinities <10 ppt, but at higher salinities a dispersion in Vibrio populations was observed, which was likely due to the effect of sediment resuspension. Microcosm experiments explicitly showed the tendency of vibrios association with SPM and the presence of organic matter significantly increased the association and extended survival of vibrios. Chitin in the SPM fraction also correlated with Vibrio numbers in the high and mid saline regions (2-20 ppt). A simple prediction model with linear regression of salinity and turbidity values was formulated which could efficiently predict the changes in estuarine Vibrio populations.It can be concluded that cyclone-mediated intrusion of saline water along with the increase in turbidity, suspended organic matter and chitin in tropical estuaries may favor Vibrio populations, with increasing risks for aquatic resources and human health in the coastal zone.