Senior Project Advisor

Van Alstyne, Kathryn Lyn, 1962-

Document Type


Publication Date

Spring 2007


Ulvoid algae, Macroalgal blooms


Macroalgal blooms are occurring more frequently worldwide. In particular, ulvoid algal species are creating harsh living conditions for several intertidal species of plants and animals. It is not understood yet why this is taking place but a large amount of effort has been allocated to projects for this very purpose. There are several hypotheses as to why ulvoid algae has increased in the last few decades. Eutrophication is a likely cause for the blooms that may be aided by the fact that ulvoids produce compounds that have been found to be feeding deterrents to certain herbivores such as the green sea urchin. In this study, several feeding experiments were carried out in the field looking at the relative palatability to sea urchins, growth rates, and chemical makeup of a few different algal species (green, red, and kelp) with and without added nutrients. While nutrients were not found to play any part in increasing growth or consumption, it was clear through these experiments that urchins prefer Viva lactuca to Vivaria obscura and Chondracanthus exasperatus (a red algae) to ulvoids in general. Interesting results were found in the chemical aspect of this study as well. DMSP levels were higher in the absence of added nutrients and urchins preferred algal species with higher carbon to nitrogen ratios giving more evidence to the fact that chemical defenses are present in ulvoids. This data will aid scientists in better understanding macroalgal blooms and creates many new questions for further research.


Environmental Studies

Subjects - Topical (LCSH)

Green sea urchins--Food; Green sea urchins--Washington (State)--Penn Cove; Marine algae--Washington (State)--Penn Cove; Marine ecology--Washington (State)--Penn Cove

Geographic Coverage

Penn Cove (Wash.)


student projects; term papers




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