Spatial heterogeneity and seasonal succession of phytoplankton functional groups along the vertical gradient in a mesotrophic reservoir

Abstract

-Tracking morphological variability of phytoplankton is a useful tool to better understand environmental changes. Highly dynamic systems such as reservoirs are convenient environments to investigate the effects of environmental variables on phytoplankton morphology. However, to fully understand the effects of mixing and trophic state on phytoplankton functional group (FG) distribution, the entire water column must be considered since integrated or sub-superficially collected samples, may not adequately represent phytoplankton structure. This idea was tested by analyzing vertical profiles of phytoplankton FGs, their relative biomass, physical and chemical parameters, through monthly samplings over a 2 years period, at three stations located along the longitudinal axis in the monomictic, mesotrophic İkizcetepeler reservoir, northwestern part of Turkey. Thermal stratification occurred in the reservoir from April to September, and z mix /z eu values increased after the breaking down of the thermocline. Nine FGs characterized the seasonal cycle and C-strategist organisms were typical representatives of the assemblages. Nutrient availability and temperature were found to influence phytoplankton dynamics, whereas water withdrawal played a secondary role. Groups Y, P, B, J, F, Lo and Tc showed heterogeneous distribution along the water column and, temperature heterogeneity, high DIN values in surface waters, z mix /z eu values and sedimentation loss were the most important factors regulating their distribution. The results show that phytoplankton morphological spectrum throughout the entire water column, contributes useful information to assess the influence of mixing and trophic state on phytoplankton dynamics in mesotrophic reservoirs.

Biological Assessment of Water Quality: Ecological Status of Three Aegean Reservoirs Based on Phytoplankton Metrics

“…During the present study, Bacillariophyta was the most dominant group in the phytoplankton composition. Dominancy of this group in phytoplankton community is also agreement with previous studies in Valparáiso Reservoir (Negro et al 2000), El Gergal Reservoir (Hoyer et al 2009) Spain, Marathonas Reservoir (Greece) (Katsiapi et al 2011), Paraja limno-Reservoir in Spain (Molina-Navarro et al 2014) and in Alleben Reservoir by Çelekli and Öztürk (2014) and İkizcetepeler Reservoir by Sevindik et al (2017) in Turkey.…”

“…The reservoirs showed alkaline water with pH ranged from 8.7 to 8.8. These pH values were higher than the mean pH value found at Alleben Reservoir (Çelekli and Öztürk, 2014) and similar to those found at İkizcetepeler Reservoir by Sevindik et al (2017) in Turkey. The highest conductivity (434.5 µS cm -1 ) and salinity (0.21 ppt) were measured at Sevişler Reservoir.…”

Driving factors affecting the phytoplankton functional groups in a deep alkaline lake

“…The codon L O , which is known to regulate its buoyancy and tolerate low nutrient concentrations (Petar et al, 2014), showed a negative correlation with NO 2 + NO 3 (r = -0.621; P < 0.05) and TP (r = -588; P < 0.05) in the lake. Similarly, Sevindik et al (2017) detected the codon L O and F in the mesotrophic İkizcetepeler reservoir during the summer period.…”

“…Few studies had also been conducted to use PFGs in determination of the water quality of Turkish reservoirs and lakes in recent years (Soylu and Gönülol, 2010;Çelekli and Öztürk, 2014;Demir et al, 2014;Maraşlıoğlu and Gönülol, 2014;Çelik and Sevindik, 2015;Sevindik et al, 2017;Varol, 2019).…”

Spatial distribution, bioavailability, and toxicity of metals in surface sediments of tropical reservoirs, Brazil

“…This analysis employed the integrated water column, which was collected using a plastic tube 2 cm in diameter (INAG 2009;Navarro et al 2006;Becker et al 2010). The integrated water column represented the depth of the photic zone, which was determined by multiplying the Secchi disk depth by 2.7 (Cole 1994;Huszar et al 2000;Soares et al 2008;Sevindik et al 2017). Previous studies have linked the eutrophication of some of the studied reservoirs (Mariani and Pompêo 2008) to metals contamination, and the TSI is an important tool for evaluation of the allochthonous contribution of possible contaminants in the aquatic ecosystem.…”