This week we welcome our own Sarah Hasnain.
Daphnia vertical position and implications for the impact of the invasive Spiny Water Flea, Bythotrephes longimanus, on plankton communities
The introduction of the Spiny Water Flea (Bythotrephes longimanus) in North American lakes has reduced zooplankton abundance and diversity, especially for cladocerans such as Daphnia. Studies have shown that in some invaded lakes Daphnia occupy a deeper vertical in the water column during the day, thereby reducing overlap with Bythotrephes, a visual predator restricted to shallow, light penetrating regions. However, Daphnia daytime vertical position is also influenced by a number of factors including resource availability and UV exposure. The goal of my PhD research was to assess if abiotic factors influence Daphnia vertical position response to Bythotrephes and determine if differences in Daphnia vertical position influence the impact of this predator on plankton communities. My results suggest that Daphnia vertical position in invaded lakes is influenced by water clarity and that Daphnia vertical position mediates Bythotrephes impact on plankton communities.