Upward phosphorus transport by Daphnia diel vertical migration

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.

5α-cyprinol sulfate, a bile salt from fish, induces diel vertical migration in Daphnia

“…Hence, DVM of Daphnia negatively affects the foraging success of planktivorous fish. This behavioral anti-predator defense affects the control of planktonic primary producers by zooplankton in the open water and thus impacts many other ecosystem-wide processes (Haupt et al, 2010; Reichwaldt and Stibor, 2005).…”

Anoxia begets anoxia: A positive feedback to the deoxygenation of temperate lakes

“…While the directionality of this relationship can be difficult to identify in the absence of detailed nutrient input data (i.e., epilimnetic TP can affect hypolimnetic TP, vice versa, or a third driver may simultaneously influence both), existing research provides strong support for this effect. Elevated hypolimnetic TP concentrations can increase epilimnetic TP concentrations within a summer stratified period through organism‐mediated transport, diffusion, and internal seiche dynamics (e.g., Carpenter et al., 1992; Cottingham et al., 2015; Haupt et al., 2010; Kamarainen et al., 2009; Nürnberg, 2009; Soranno et al., 1997). At the onset of autumn mixing, the concentration of TP in the hypolimnion fundamentally determines the amount of potential TP input to the epilimnion, which can have legacy effects throughout the subsequent autumn, winter, and spring (e.g., Nürnberg & Peters, 1984; Wang et al., 2019).…”

“…However, while redox‐controlled phosphorus release fluxes have received significant attention, sediment characteristics, microbial processing, and catchment inputs may also play important roles in phosphorus dynamics (e.g., Hupfer & Lewandowski, 2008; Orihel et al., 2017). Increases in hypolimnetic total phosphorus (TP) are expected to increase surface water (epilimnetic) TP concentrations within a summer stratified period through both biological and physical processes (e.g., organism‐mediated transport, diffusion, and internal seiche dynamics; Carpenter et al., 1992; Cottingham et al., 2015; Haupt et al., 2010; Kamarainen et al., 2009) or during autumn mixis when epilimnetic and hypolimnetic waters homogenize (e.g., Nürnberg & Peters, 1984; Wetzel, 2001; Figure 1b). Higher epilimnetic TP concentrations in turn can stimulate phytoplankton growth in many lakes, thereby increasing chlorophyll a (chl a , Figure 1c; Schindler, 1974), though many other important factors, including nitrogen concentrations, climate, and light availability, also contribute to phytoplankton growth (e.g., Paerl & Huisman, 2008; Reinl et al., 2023).…”

Mesocosm experiments validate induction of Daphnia vertical migration by the fish‐derived kairomone 5α‐cyprinol sulfate

“…The metabolic costs associated with DVM (Loose and Dawidowicz 1994) are compensated by reduced predation losses (Lampert 1993). DVM contributes substantially to vertical nutrient transport (Haupt et al 2009(Haupt et al , 2010 and to the biological carbon pump in marine systems (Brierley 2014), while also affecting the foraging of planktivorous fish and distribution of phytoplankton biomass (Reichwaldt and Stibor 2005;Haupt et al 2009).…”