Impact of the 2009 extreme water level variation on phytoplankton community structure in Lower Amazon floodplain lakes

Abstract

AIM: This paper examines the effect of the extreme water level change in 2009 on the structure and diversity of the phytoplankton communities in lakes of the Lower Amazon Floodplain, and compares it to phytoplankton community structure data reported in the literature for 2002 and 2003 high water periods, closer to the normal hydrological conditions. METHODS: Sub-surface integrated water samples for phytoplankton and chlorophyll-a analyses were collected during high and low water phases in 2009. Water temperature (°C), pH, turbidity (NTU) and electrical conductivity (µS.m-1) were measured, and the Shannon diversity index was calculated. RESULTS: The results showed striking differences in taxonomic composition between phases (high and low) and also between normal (2002 and 2003) and extreme (2009) hydrological conditions, all related to the flood pulse intensity. CONCLUSIONS: Extreme water level fluctuations can result in shifts in phytoplankton community structure and diversity. This work represents a valuable contribution to phytoplankton research since presents the community structure under extreme hydrological events in the Amazon floodplain.

Spatial and temporal variability of light attenuation in large rivers of the Amazon

“…The low autochthonous primary production in these Amazonian rivers is well documented in terms of low chlorophyll concentrations and productivity (Fisher, 1979;Putz & Junk, 1997;Melack & Forsberg, 2001). According to our biomarker pigment results, the low productivity is represented by Cyanophyceae and Bacillariophyceae (in agreement with recent species composition data for the Amazon from Casali et al (2012)), which are known to be adapted to low light conditions (Dokulil & Teubner, 2000). Diatoms, specifically, tend to show an increase in the concentration of the light harvesting fucoxanthin pigment in low light conditions (Descy et al, 2009).…”

Retrieving Total and Inorganic Suspended Sediments in Amazon Floodplain Lakes: A Multisensor Approach

“…The low Chl-a concentration in this phase is related to the high water level of the Amazon River (See Figure 2) [22] which increases the Amazon inflow into the floodplain lakes. This high inflow increases the turbulence, preventing phytoplankton growth [60,104]. Furthermore, the overbank flow causes the input of Colored Dissolved Organic Material (CDOM), reducing light availability in the blue region within the water column which reduces the rates of phytoplankton growth [7,8,13].…”

Implications of scatter corrections for absorption measurements on optical closure of Amazon floodplain lakes using the Spectral Absorption and Attenuation Meter (AC-S-WETLabs)

“…In relation to the organic fraction of TSM (TSOM) it is composed by phytoplankton cells larger than 1 μm (Casali et al, 2011) and debris derived from decomposition of floodplain vegetation (forest, shrubs and macrophytes) much larger than phytoplankton detritus (Richey, Brock, Naiman, Wissmar, & Stallard, 1980). Hickel (1984) also arguments that because of GF filter variability in pore size, the differences between GF/C and GF/F filters could be meaningless.…”