Influence of submerged macrophytes,temperature, and nutrient loading on the development of redox potential around the sediment–water interface in lakes |
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Authors: | Email author" target="_blank">Gergely?BorosEmail author Martin?S?ndergaard Péter?Takács ágnes?Vári István?Tátrai |
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Institution: | (1) Balaton Limnological Research Institute, P. O. Box 35, Tihany, 8237, Hungary;(2) Department of Freshwater Ecology, National Environmental Research Institute, P. O. Box 314, Silkeborg, 8600, Denmark |
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Abstract: | Redox potential is a significant factor in aquatic systems to regulate the availability of nutrients and some metals. To assess
the driving variables regulating redox potential, background parameters (dissolved oxygen, pH, temperature, chlorophyll-a, soluble reactive and total phosphorus content of water, coverage and height of submerged macrophytes) and redox potential
profiles around the sediment–water interface (SWI) were measured in simulated shallow lake ecosystems. There were two nutrient
regimes (enriched and non-enriched) and three temperature scenarios (unheated; +3.5°C; +5°C) installed in the experimental
setups, which were constructed to study the effects of global climate change. Temperature did not have any detectable effect
on redox potentials, and we presume that nutrient addition had only indirect positive effects through triggering phytoplankton
dominance which causes macrophyte absence. When submerged macrophytes were present in high density (80–100% coverage), redox
potentials at the SWI varied between 60–215 mV and the mean redox potential was 133 ± 34 mV (mean ± 1 SD). In contrast to
this, when phytoplankton dominance was coupled to low macrophyte density (0–20% coverage), the range of redox potentials at
the SWI was 160–290 mV and the mean redox potential was 218 ± 34 mV. The results revealed the primary importance of submersed
macrophytes; macrophyte coverage determined alone the redox potential of the sediment–water interface by 81%. This study suggests
that possible positive effects of macrophytes on redox potential can be suppressed by their negative effects in case of 80–100%
coverage and total inhabitation of the water column. |
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