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Herwig Stibor - One of the best experts on this subject based on the ideXlab platform.

  • upward phosphorus transport by daphnia diel vertical migration
    Limnology and Oceanography, 2010
    Co-Authors: Florian Haupt, Maria Stockenreiter, Elke S Reichwaldt, Michaela Baumgartner, Winfried Lampert, Maarten Boersma, Herwig Stibor
    Abstract:

    In many lakes, zooplankton show a distinct diel vertical migration (DVM) behavior, especially during periods of stratification. Excretion products of these zooplankton could potentially cause an upward nutrient transport and consequent nutrient enrichment for phytoplankton in the Epilimnion. We quantified the upward transport of phosphorus by the cladoceran Daphnia DVM experimentally by adding a radioactive tracer (33P) to the hypolimnion of large indoor mesocosms and measuring tracer accumulation in the Epilimnion over time. During the daytime, when all Daphnia were found in the hypolimnion, no phosphorus transport from the hypolimnion into the Epilimnion took place. As soon as the Daphnia started their upward migration, around dusk, we observed a continuous increase in phosphorus concentration in the Epilimnion. The amount of phosphorus transported was in a biologically meaningful range. Our results strongly suggest that Daphnia vertical migration presents a continuous nutrient supply for the Epilimnion. Diel vertical migration (DVM) of zooplankton is one of the world’s largest synchronized movements of animals (Hays 2003). It is a daily habitat shift of zooplankton from deeper water regions during the day to surface waters at

  • The impact of diel vertical migration of Daphnia on phytoplankton dynamics
    Oecologia, 2005
    Co-Authors: Elke S Reichwaldt, Herwig Stibor
    Abstract:

    Diel vertical migration (DVM) of large zooplankton is a very common phenomenon in the pelagic zone of lakes and oceans. Although the underlying mechanisms of DVM are well understood, we lack experimental studies on the consequences of this behaviour for the zooplankton’s food resource—the phytoplankton. As large zooplankton species or individuals migrate downwards into lower and darker water strata by day and upwards into surface layers by night, a huge amount of herbivorous biomass moves through the water column twice a day. This migration must have profound consequences for the phytoplankton. It is generally assumed that migration supports an enhanced phytoplankton biomass and a change in the composition of the phytoplankton community towards smaller, edible algae in the Epilimnion of a lake. We tested this assumption for the first time in field experiments by comparing phytoplankton biomass and community assemblage in mesocosms with and without artificially migrating natural stocks of Daphnia hyalina . We show that DVM can enhance phytoplankton biomass in the Epilimnion and that it has a strong impact on the composition of a phytoplankton community leading to an advantage for small, edible algae. Our results support the idea that DVM of Daphnia can have strong effects on phytoplankton dynamics in a lake.

Winfried Lampert - One of the best experts on this subject based on the ideXlab platform.

  • upward phosphorus transport by daphnia diel vertical migration
    Limnology and Oceanography, 2010
    Co-Authors: Florian Haupt, Maria Stockenreiter, Elke S Reichwaldt, Michaela Baumgartner, Winfried Lampert, Maarten Boersma, Herwig Stibor
    Abstract:

    In many lakes, zooplankton show a distinct diel vertical migration (DVM) behavior, especially during periods of stratification. Excretion products of these zooplankton could potentially cause an upward nutrient transport and consequent nutrient enrichment for phytoplankton in the Epilimnion. We quantified the upward transport of phosphorus by the cladoceran Daphnia DVM experimentally by adding a radioactive tracer (33P) to the hypolimnion of large indoor mesocosms and measuring tracer accumulation in the Epilimnion over time. During the daytime, when all Daphnia were found in the hypolimnion, no phosphorus transport from the hypolimnion into the Epilimnion took place. As soon as the Daphnia started their upward migration, around dusk, we observed a continuous increase in phosphorus concentration in the Epilimnion. The amount of phosphorus transported was in a biologically meaningful range. Our results strongly suggest that Daphnia vertical migration presents a continuous nutrient supply for the Epilimnion. Diel vertical migration (DVM) of zooplankton is one of the world’s largest synchronized movements of animals (Hays 2003). It is a daily habitat shift of zooplankton from deeper water regions during the day to surface waters at

  • exploitation of a deep water algal maximum by daphnia a stable isotope tracer study
    Hydrobiologia, 2003
    Co-Authors: Winfried Lampert, Jonathan Grey
    Abstract:

    The exploitation of a deep algal maximum by Daphnia in the absence of fish predation was studied in large indoor mesocosms. Facing the dilemma of low food but high temperature in the Epilimnion vs. high food but low temperature in the hypolimnion, Daphnia distribute above and below the thermocline in order to optimise their fitness. Labelling hypolimnetic algae with 15N revealed that the vertical distribution of Daphnia is dynamic, i.e., all individuals traverse the thermocline and allocate a certain proportion of their time to feeding in the cold water. The overall energy gain from the deep-water algal maximum is lower than from the same algal concentration in the Epilimnion due to the low temperature and the limited time an individual spends in the hypolimnion. The results provide mechanistic support for the hypothesis that Daphnia chose their habitat according to an Ideal Free Distribution with Costs model.

Elke S Reichwaldt - One of the best experts on this subject based on the ideXlab platform.

  • upward phosphorus transport by daphnia diel vertical migration
    Limnology and Oceanography, 2010
    Co-Authors: Florian Haupt, Maria Stockenreiter, Elke S Reichwaldt, Michaela Baumgartner, Winfried Lampert, Maarten Boersma, Herwig Stibor
    Abstract:

    In many lakes, zooplankton show a distinct diel vertical migration (DVM) behavior, especially during periods of stratification. Excretion products of these zooplankton could potentially cause an upward nutrient transport and consequent nutrient enrichment for phytoplankton in the Epilimnion. We quantified the upward transport of phosphorus by the cladoceran Daphnia DVM experimentally by adding a radioactive tracer (33P) to the hypolimnion of large indoor mesocosms and measuring tracer accumulation in the Epilimnion over time. During the daytime, when all Daphnia were found in the hypolimnion, no phosphorus transport from the hypolimnion into the Epilimnion took place. As soon as the Daphnia started their upward migration, around dusk, we observed a continuous increase in phosphorus concentration in the Epilimnion. The amount of phosphorus transported was in a biologically meaningful range. Our results strongly suggest that Daphnia vertical migration presents a continuous nutrient supply for the Epilimnion. Diel vertical migration (DVM) of zooplankton is one of the world’s largest synchronized movements of animals (Hays 2003). It is a daily habitat shift of zooplankton from deeper water regions during the day to surface waters at

  • The impact of diel vertical migration of Daphnia on phytoplankton dynamics
    Oecologia, 2005
    Co-Authors: Elke S Reichwaldt, Herwig Stibor
    Abstract:

    Diel vertical migration (DVM) of large zooplankton is a very common phenomenon in the pelagic zone of lakes and oceans. Although the underlying mechanisms of DVM are well understood, we lack experimental studies on the consequences of this behaviour for the zooplankton’s food resource—the phytoplankton. As large zooplankton species or individuals migrate downwards into lower and darker water strata by day and upwards into surface layers by night, a huge amount of herbivorous biomass moves through the water column twice a day. This migration must have profound consequences for the phytoplankton. It is generally assumed that migration supports an enhanced phytoplankton biomass and a change in the composition of the phytoplankton community towards smaller, edible algae in the Epilimnion of a lake. We tested this assumption for the first time in field experiments by comparing phytoplankton biomass and community assemblage in mesocosms with and without artificially migrating natural stocks of Daphnia hyalina . We show that DVM can enhance phytoplankton biomass in the Epilimnion and that it has a strong impact on the composition of a phytoplankton community leading to an advantage for small, edible algae. Our results support the idea that DVM of Daphnia can have strong effects on phytoplankton dynamics in a lake.

Cayelan C Carey - One of the best experts on this subject based on the ideXlab platform.

  • the effects of hypolimnetic anoxia on the diel vertical migration of freshwater crustacean zooplankton
    Ecosphere, 2018
    Co-Authors: Jonathan P Doubek, Kylie L Campbell, Kaitlyn M Doubek, Kathleen D Hamre, Mary E Lofton, Ryan P Mcclure, Nicole K Ward, Cayelan C Carey
    Abstract:

    Lakes and reservoirs worldwide are increasingly experiencing depletion of dissolved oxygen (anoxia) in their bottom waters (the hypolimnion) because of climate change and eutrophication, which is altering the dynamics of many freshwater ecological communities. Hypolimnetic anoxia may substantially alter the daily migration and distribution of zooplankton, the dominant grazers of phytoplankton in aquatic food webs. In waterbodies with oxic hypolimnia, zooplankton exhibit diel vertical migration (DVM), in which they migrate to the dark hypolimnion during the day to escape fish predation or ultraviolet (UV) radiation damage in the well‐lit surface waters (the Epilimnion). However, due to the physiologically stressful conditions of anoxic hypolimnia, we hypothesized that zooplankton may be forced to remain in the Epilimnion during daylight, trading oxic stress for increased predation risk or UV radiation damage. To examine how anoxia impacts zooplankton vertical migration, distribution, biomass, and community composition over day–night periods, we conducted multiple diel sampling campaigns on reservoirs that spanned oxic, hypoxic, and anoxic hypolimnetic conditions. In addition, we sampled the same reservoirs fortnightly during the daytime to examine the vertical position of zooplankton throughout the summer stratified season. Under anoxic conditions, most zooplankton taxa were predominantly found in the Epilimnion during the day and night, did not exhibit DVM, and had lower seasonal biomass than in reservoirs with oxic hypolimnia. Only the phantom midge larva, Chaoborus spp., was consistently anoxia‐tolerant. Consequently, our results suggest that hypolimnetic anoxia may alter zooplankton migration, biomass, and behavior, which may in turn exacerbate water quality degradation due to the critical role zooplankton play in freshwater ecosystems.

  • Chaoborus spp. Transport CH4 from the Sediments to the Surface Waters of a Eutrophic Reservoir, But Their Contribution to Water Column CH4 Concentrations and Diffusive Efflux Is Minor
    2017
    Co-Authors: Cayelan C Carey, Jonathan P Doubek, Mary E Lofton, Ryan P Mcclure, Nicole K Ward, Durelle T. Scott
    Abstract:

    Chaoborus spp. (midge larvae) live in the anoxic sediments and hypolimnia of freshwater lakes and reservoirs during the day and migrate to the surface waters at night to feed on plankton. It has recently been proposed that Chaoborus take up methane (CH4) from the sediments in their tracheal gas sacs, use this acquired buoyancy to ascend into the surface waters, and then release the CH4, thereby serving as a CH4 “pump” to the atmosphere. We tested this hypothesis using diel surveys and seasonal monitoring, as well as incubations of Chaoborus to measure CH4 transport in their gas sacs at different depths and times in a eutrophic reservoir. We found that Chaoborus transported CH4 from the hypolimnion to the lower Epilimnion at dusk, but the overall rate of CH4 transport was minor, and incubations revealed substantial variability in CH4 transport over space and time. We calculated that Chaoborus transport ∼0.1 mmol CH4 m–2 yr–1 to the Epilimnion in our study reservoir, a very low proportion (

Maarten Boersma - One of the best experts on this subject based on the ideXlab platform.

  • upward phosphorus transport by daphnia diel vertical migration
    Limnology and Oceanography, 2010
    Co-Authors: Florian Haupt, Maria Stockenreiter, Elke S Reichwaldt, Michaela Baumgartner, Winfried Lampert, Maarten Boersma, Herwig Stibor
    Abstract:

    In many lakes, zooplankton show a distinct diel vertical migration (DVM) behavior, especially during periods of stratification. Excretion products of these zooplankton could potentially cause an upward nutrient transport and consequent nutrient enrichment for phytoplankton in the Epilimnion. We quantified the upward transport of phosphorus by the cladoceran Daphnia DVM experimentally by adding a radioactive tracer (33P) to the hypolimnion of large indoor mesocosms and measuring tracer accumulation in the Epilimnion over time. During the daytime, when all Daphnia were found in the hypolimnion, no phosphorus transport from the hypolimnion into the Epilimnion took place. As soon as the Daphnia started their upward migration, around dusk, we observed a continuous increase in phosphorus concentration in the Epilimnion. The amount of phosphorus transported was in a biologically meaningful range. Our results strongly suggest that Daphnia vertical migration presents a continuous nutrient supply for the Epilimnion. Diel vertical migration (DVM) of zooplankton is one of the world’s largest synchronized movements of animals (Hays 2003). It is a daily habitat shift of zooplankton from deeper water regions during the day to surface waters at

  • How do migrating daphnids cope with fish predation risk in the Epilimnion under anoxic conditions in the hypolimnion
    Journal of Plankton Research, 2000
    Co-Authors: Sandra Lass, Maarten Boersma, Piet Spaak
    Abstract:

    The vertical distribution of Daphnia in experimental tubes is influenced by fish kairomone concentration in the 'Epilimnion' and oxygen conditions in the 'hypolimnion'. Daphnids trade off reduced predation mortality in a refuge against disadvantages due to unfavourable oxygen conditions.