Browsing by Subject "Wastewater algal cultivation"
Now showing 1 - 1 of 1
- Results Per Page
- Sort Options
Item Exploring new varieties and applications of trophic cascades using pond species interaction experiments and theory(2023-05-01) Rakowski, Chase J.; Leibold, Mathew A.; Farrior, Caroline E.; Manning, Schonna R; Jha, Shalene; Theriot, Edward CGlobal change is altering the diversity, composition, and interactions of predator species even more rapidly than those of lower trophic levels. While many of the most important ecosystem functions and services such as primary production are provided by bottom trophic levels, we know from the classic trophic cascade concept that these ecosystem properties can be strongly impacted by predators via chains of species interactions. However, the relationships between changing attributes of predator communities and these key ecosystem properties at the base of the food web remain unclear. I identify three ways that the trophic cascade concept can be expanded to help fill this knowledge gap. First, ecologists can assess cascading consequences of changes in predator diversity or interactions rather than the less realistic addition or removal of entire top trophic levels. Second, trophic cascade research can move away from an equilibrium approach to incorporate the food web dynamics that determine ecosystem stability. Third, there is understudied potential for the application of trophic cascade theory to improving environmental technologies involving the cultivation of microalgae. In Chapter One I experimentally test the effects of insect predator diversity on the central tendency and variability of pond plankton biomass. I find that the insect species better suppress their collective zooplankton prey when together, leading to less variable phytoplankton biomass. In Chapter Two I analyze a food web model to explore the influence of the degree of intraguild predation on the variability of biomass of lower trophic levels. I show that stronger intraguild predation is associated with biomass fluctuations throughout the food web. Finally, in Chapter Three I experimentally show that fish can provide effective biological control in wastewater algal raceway ponds, increasing algal biomass though not necessarily improving nutrient removal from the wastewater. Overall, the present dissertation describes two novel varieties of trophic cascades and expands upon a new application. These links between the top and bottom ends of food webs predict consequential effects of changes in predator communities, and they also suggest strategies for ecosystem management in pursuit of reliable ecosystem services.