Skip to main content
2023 ESA Annual Meeting Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.
Back

Contributed Talk

Session: : Aquatic Ecology: Lakes And Ponds 1

COS 48-4 - CANCELLED - The effects of salinization and climate change on shallow lakes of arid landscapes: two mesocosm experiments in two different climate zones in Türkiye

Tuesday, August 8, 2023
8:45 AM – 9:00 AM PDT
Location: B111

    Presenting Author(s)

  • KÃ

    Korhan Özkan

    Institute of Marine Sciences, Middle East Technical University, Turkey

    • Coauthor(s)

  • CA

    Cihelio Alves Amorim

    Department of Biological Sciences, Middle East Technical University, Turkey

  • GY

    Gültekin Yılmaz

    Institute of Marine Sciences, Middle East Technical University, Turkey

  • Mk

    Mustafa korkmaz

    Institute of Marine Sciences, Middle East Technical University, Turkey

  • JP

    Juan Pablo Pacheco

    Department of Biological Sciences, Middle East Technical University, Turkey

  • GY

    Gül canan Yavuz

    Department of Biological Sciences, Middle East Technical University, Turkey

  • VA

    Vildan Acar

    Department of Biological Sciences, Middle East Technical University, Turkey

  • YC

    Yasemin Can

    Institute of Marine Sciences, Middle East Technical University, Turkey

  • MK

    Meltem Koru

    Institute of Marine Sciences, Middle East Technical University, Turkey

  • CÃ

    Can Özen

    Centre for Ecosystem Research and Implementation, Middle East Technical University, Turkey

  • ZA

    Zuhal Akyürek

    Centre for Ecosystem Research and Implementation, Middle East Technical University, Turkey

  • MB

    Meryem BeklioÄŸlu

    Department of Biological Sciences, Middle East Technical University, Turkey

  • EJ

    Erik Jeppesen

    Department of Biological Sciences, Middle East Technical University, Turkey

Abstract: Lakes located in dry landscapes have been facing dramatic pressures due to water loss and salinisation driven by excessive water use for irrigation and climate change. The impact of these pressures on the biodiversity as well as ecosystem structure and function of the lake ecosystems have not been fully accounted for. We conducted field expeditions over more than 40 lakes spanning across several hundred kilometres of Anatolian arid landscape of Türkiye, in 2021 and 2022. The results revealed a dramatic loss of biodiversity driven by water loss and significant shifts in lake ecosystem structure and function across a large salinity gradient (0.25-259 g/L). To better elucidate the effects of salinisation and climate change on lake ecosystems, we conducted two sets of mesocosm experiments: (i) a gradient experiment with 16 different salinities (0-50 g/L) and (ii) a heatwave experiment with two salinities (4 and 40 g/L); both synchronously conducted in two different climate zones in central and coastal Turkey. All mesocosm tanks were inoculated with 30 cm of natural sediment, submerged macrophytes (Ruppia spp.), fish (Alburnus escherichii) and fresh inoculums of the water column and sediment collected from lakes with different salinities prior to the experiments. The salinity gradient experiment was conducted (September-2021 to May-2022) in three periods: increasing (30 days) salinities to target concentrations, stable (six months), and decreasing (40 days) salinities to starting conditions ( < 4 g/L). The heatwave experiment was conducted for four treatments of two salinity concentrationscrossed with the heatwave and no heatwave simulation with four replicates in each treatment in September-November 2022. The heatwave was simulated as a 6 ºC increase over ambient temperatures in control tanks for two weeks in the middle of the eight weeks of the experiment. All experiments were conducted with constant nutrient load under eutrophic conditions, mixed water column and the mesocosms were monitored twice a week. The gradient experiment revealed the predominant role of salinization in nutrient concentrations, dissolved oxygen levels, chlorophyll-a and turbidity of lake water modulated by climatic zones as well as significant shifts in the community composition of organisms over the salinity gradient. The heatwave experiment revealed that the predominant effect of salinization on eutrophic lakes might further be modulated by climate change, especially for primary production and water transparency. Both field surveys and mesocosm experiments revealed predominant negative effects of water loss and salinization on biodiversity, ecosystem metabolism, and, thus, on the ecosystem functioning of lakes.