Rivers affect the biovolume and functional traits of phytoplankton in floodplain lakes

Alfonso Pineda,Aline Caroline Magro De Paula,Yasmin Rodrigues De Souza,Larissa Mozini Reis,Luciane Maria Nogueira,Luzia Cleide Rodrigues,Patricia Iatskiu,Geovani Arnhold Moresco

doi:10.1590/s2179-975x7317

Alfonso Pineda, Aline Caroline Magro De Paula + Show 6 more

Open Access

https://doi.org/10.1590/s2179-975x7317

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Abstract

Abstract Aim: We analyzed the temporal distribution (dry and rainy periods) of phytoplankton functional groups (biovolume) from lakes connected to dammed (S1 - Paraná River) and non-dammed rivers (S2 - Baia River and S3 - Ivinhema River) in the upper Paraná River floodplain, Brazil. We also determined the drivers of the phytoplankton community assemblage. Methods Phytoplankton and environmental variables samplings were performed quarterly in dry (2000 and 2001) and rainy (2010 and 2011) periods. We classified the phytoplankton species into seven morphological based functional groups (MBFG). We used analysis of variance to test differences in total phytoplankton biovolume and MBFGs biovolume between lakes and climatic periods. We also used redundancy analysis to determine the MBFGs-environment relation. Results The lake related to the dammed river (S1) presented the lowest species richness. The total phytoplankton biovolume presented differences among the lakes, but we did not register temporal differences associated with water level variation. The lake related to the non-dammed and semi-lentic river (S2) presented the highest biovolume, while S1 (related to the dammed river) and S3 (related to the non-dammed river) exhibited the lowest ones. Filamentous organisms (MBFG III) were associated with poor nutrient conditions and diatoms (MBFG VI) were favored in high water mixing sites. The flagellate groups MBFG II and MBFG V were related to deeper water and lower column mixing conditions, respectively. Conclusions Our results suggest that phytoplankton species with different functional traits drive the primary productivity in the dry and rainy periods. Hence, we highlight the importance of maintaining high functional diversity in lakes to ensure primary productivity. Therefore, we stress the importance of protecting the natural environment such as floodplain lakes because of its contribution to the regional biodiversity and the flow of energy.

Highlights

Floodplains are fluvial macro-systems (Neiff, 1990) of high functional and structural complexity, formed by aquatic habitats of notable biodiversity, especially in relation to the phytoplankton community (Thomaz et al, 2004; Train & Rodrigues, 2004)
Aim: We analyzed the temporal distribution of phytoplankton functional groups from lakes connected to dammed (S1 - Paraná River) and non-dammed rivers (S2 - Baia River and S3 - Ivinhema River) in the upper Paraná River floodplain, Brazil
Our results show that environmental factors affect the distribution of phytoplankton functional traits in floodplain lakes, and highlight the importance of niche-associated processes to the assemblage of the phytoplankton community

Summary

Introduction

Floodplains are fluvial macro-systems (Neiff, 1990) of high functional and structural complexity, formed by aquatic habitats of notable biodiversity, especially in relation to the phytoplankton community (Thomaz et al, 2004; Train & Rodrigues, 2004). The hydrosedimentological regime is the main driving force controlling the flow of matter and energy (Neiff, 1990, 1996). This regime presents high water periods in which there is high connectivity between the main channel and adjacent environments, and low water periods in which the adjacent environments become more isolated (Neiff, 1990, 1996). Water level variation of the main channel influences the dynamic of the whole floodplain, the effect on the associated lakes and rivers depends on the size, position and the level of connection of these environments (Junk et al, 1989)

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