Honors Program


Document Type


Date of this Version

Spring 5-2020


Welchans, B. 2020. Diatom Morphology in Light of a Changing Climate: A Focus on Aulacoseira crenulata. Undergraduate Honors Thesis. University of Nebraska-Lincoln.


Copyright Brighid Welchans 2020.


Fossilized diatoms are arguably the most vital proxy record utilized in paleolimnology. Diatoms are unicellular microalgae that are the basis of countless food webs, are invaluable bioindicators, and generate nearly a quarter of global net primary productivity. Diatoms are affected by a variety of environmental factors but there is relatively little research on how environmental conditions impact diatom valve morphology, and in particular whether there is a correlation between incoming light and diatom pore morphology. This report focuses on the Amazon lowland lake Garzacocha, and analyzes the relationship between light levels and the corresponding size of Aulacoseira crenulata pores. We hypothesize that if pore size of Aulacoseira crenulata was larger than the overall average pore size of 0.632 μm, sunlight was at lower levels. If pore size of Aulacoseira crenulata was smaller than 0.632 μm, sunlight was at higher levels. Our results suggest an indirect relationship between light availability and pore size of Aulacoseira crenulata. Future research on this relationship is needed, and efforts to identify the existence of this relationship in other diatom communities and geographic locations is suggested.

thesis poster.pptx (7386 kB)