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Date of Award

Spring 2023

Document Type

Masters Thesis

Department or Program Affiliation

Marine and Estuarine Science Program

Degree Name

Master of Science (MS)



First Advisor

Olson, M. Brady (Michael Brady)

Second Advisor

Cooper, W. James, 1969-

Third Advisor

Lemkau, Karin


Diatoms are ubiquitous in marine planktonic and benthic environments and are common in diets for many lower-trophic organisms. Certain species of diatoms produce polyunsaturated aldehydes (PUAs) that can exist in particulate and dissolved forms. Diatom PUAs are known for negatively affecting the fecundity of their primary consumers, including invertebrate grazers like copepods and echinoderms. However, little is known about the effects of diatom PUAs on vertebrates that may be exposed to dissolved or ingested PUAs due to overlapping distribution with diatom populations. The purpose of this study was to test whether dissolved diatom PUAs affect the early life stages of a model fish, Danio rerio (zebrafish). To test this, zebrafish embryos and larvae were exposed to proportionally increasing mixtures of the dissolved diatom PUAs 2E,4E-decadienal, 2E,4E-octadienal and 2E,4E-heptadienal. Under PUA exposure three metrics of fitness were assessed: embryo heart rate, larval size at hatch, and pre-feeding rate of mortality. In the embryo heart rate experiment, embryos exposed at 24 hours post fertilization (hpf) experienced decreased average heart rate after 2 days of PUA exposure. Embryos 24 hpf exposed to PUA mixtures for 6 days showed a reduction in size in comparison to embryos from controls. Embryos exposed to PUAs from 2 hpf until death showed lower survivorship compared to larvae in controls. The results of this study suggest that larval fish that are sympatric with PUA producing diatoms during their embryonic and larval stages may be susceptible to detrimental effects from PUA exposure.




diatoms, forage fish, larval fish, zebrafish, danio rerio, polyunsaturated aldehydes, survival, heart rate, morphology, morphometrics


Western Washington University

OCLC Number


Subject – LCSH

Diatoms; Polyenes; Zebra danio--Larvae; Morphology




masters theses




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