Fig. 1 — Two species of duckweeds, Lemna minor (L) and Spirodela polyrhiza (R) share similar habitats, yet their different overwintering strategies and temperature optima allow them to coexist.

Fig. 1 — Two species of duckweeds, Lemna minor (L) and Spirodela polyrhiza (R) share similar habitats, yet their different overwintering strategies and temperature optima allow them to coexist.

Fig. 2 —  The coexistence of two species of duckweed appears to be due to a combination of relative differences in their thermal response curves (serving to equalize long-term average fitnesses), and stabilization from the effects of both dormant life history stages (fluctuation-dependent) and negative frequency-dependent growth (fluctuation-independent).

Fig. 2 —  The coexistence of two species of duckweed appears to be due to a combination of relative differences in their thermal response curves (serving to equalize long-term average fitnesses), and stabilization from the effects of both dormant life history stages (fluctuation-dependent) and negative frequency-dependent growth (fluctuation-independent).

Experimental approaches to coexistence & succession

For my postdoctoral research, I am using both floating aquatic duckweed plants (Lemnaceae) and environmental bacterial isolates to experimentally quantify the importance of various coexistence mechanisms. For instance, I study how dormant life stages (e.g., spores, seeds, turions) allow organisms to persist in fluctuating environments via storage effects and relative nonlinearities.

Fig. 3 — Bacterial isolates can be evolved to express biomarkers (e.g., antibiotic resistance) for the purposes of tracking low-abundance individual cell lines in mixed cultures.

Fig. 3 — Bacterial isolates can be evolved to express biomarkers (e.g., antibiotic resistance) for the purposes of tracking low-abundance individual cell lines in mixed cultures.