4 DISCUSSION
Phytoplankton dynamic
Temporal changes in the water column
stability of the reservoir, related to
physical characteristics (stratification vs.
mixing) and meteorological variables,
are one of the main environmental
forces that affect phytoplankton dynamic
(Harris, 1986; Henry, 1999; Dos Santos
& Calijuri, 1998; Han et al., 2000). The
NT2 Reservoir was impounded during
the WW season 2008. During the early
stage of impoundment, the reservoir undergoes rapid and extensive fluctuations
in flow and water levels (June and
July 2009). As shown by Martinet et al.
(2014), at the inter-annual scale, successions
of phytoplankton could be
explained by hydrological factors such
as impoundment of the reservoir and
spillage (results from dam site sampling
at RES1). This previous study has
shown that phytoplankton biomass
declined during the period of rainfalls.
This is also observed in the sampling
sites located at the former riverbed with
a decline of total biomass for the whole
set of samples.