Date of Award

2018

Document Type

Open Access Thesis

Department

Marine Science

Sub-Department

College of Arts and Sciences

First Advisor

Tammi Richardson

Abstract

Cryptophytes are eukaryotic algae found in a variety of aquatic ecosystems, that vary in the color of light available for photosynthesis. This algal division displays a diversity in necessary photosynthetic pigments, possessing either phycoerythrin (Cr-PE; “pink”) phycocyanin (Cr-PC; “green”). According to the theory of complementary chromatic adaptation, this diversity should help maximize absorption of light within natural environments. The objective of this study was to determine if pigmentation related to growth performance in environments of differing spectral irradiance. Eight species of marine cryptophytes (5 Cr-PE and 3 Cr-PC species) were grown under four different spectral light environments. Growth rates, cellular pigment concentration and volume, and absorption spectra were determined for all experimental species and light treatments. Cr-PE species grew fastest under blue light (0.4 to 0.6 d-1 depending on species), indicating the efficient absorbance of blue photons by their Cr-PEs and by non- PE pigments. Cr-PC cryptophytes grew fastest under red, white, or blue light depending on the species (0.5 to 0.8 d-1), which Cr-PC they contained and their complement of non- PC pigments. All Cr-PC species grew slowest under green light (0.3 to 0.5 d-1). Spectral irradiance had a significant impact on cellular pigment concentrations and cellular volumes; however, the results varied among species. This study showed that cryptophytes could acclimate to novel environments, as no mortality was observed. Future studies will look at longer term acclimation (at the scale of years) to determine if cryptophytes show adaptive capabilities that are expressed at the genetic level.

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