AOGS-AGU (WPGM) JOINT ASSEMBLY,2012
International conference, Singapore,13-17th August 2012.
Stimulation of Estuarine Biological Pump for CO2 Using Gibberelic Acid
Chumki CHOWDHURY1#+, Tapan Kumar JANA11University of Calcutta, India
#Corresponding author: chowdhurychumki@gmail.com +Presenter
An estuary can be a source for CO2 when heterotrophic production predominates over phytoplankton production, resulting significant change of regional atmosphere composition with respect to carbon dioxide. For example, flux of carbon dioxide from the Mahanadi estuary to the atmosphere was found to be 52.87- 2472.16 µM.m-2.h-1 which is greater than that of Saptamukhi estuary (4.7-810.62 µM.m-2.h-1). Both the estuaries show heterotrophism and act as source for CO2. However, in case of excess nutrient input cultural eutrophication could transfom an estuary as a sink for CO2. But the effect of nutrients on phytoplankton production could soon reach saturation level at low concentration, For example half saturation concentration for inorganic nitrogen and phosphorous are 2.0-10 μM and 0.02-0.5 μM, respectively. Therefore estuaries can act as a sink for CO2 for limited period of time. To find an alternative process to gear up the biological pump could be a noble approach. This study reports the removal of excess CO2 from medium by mixed culture of phytoplankton collected from Saptamukhi estuaruy and exposed to plant growth stimulator gibberelic acid other than nutrients. The increased growth of phytoplankton further resulted into the uptake of bicarbonate and carbonate ions from the system. Gibberelic acid promoted the growth of phytoplankton upto 33% in the culture while the culture without gibberelic acid control culture showed maximum no of cell increase of 24% and 21% respectively. Cultures added with gibberelic acid showed greater uptake of bicarbonate and carbonate ions from culture than the culture without gibberelic acid and the control.
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