Jason Hall Marine and Estuarine Science Program   Department of Biology MSc completed Fall 2005 BSc Environmental Science, UW Tacoma. 2003.    Certificate in Restoration Ecology, UW Tacoma. 2003.

Project

Title: Color variability in the sponge Halichondria panicea (Demospongiae) and its impacts on the nudibranch Archidoris montereyensis (Archidorididae)

Abstract:
The color variability of the sponge Halichondria panicea (Demospongiae) occurring in the northeastern Pacific Ocean was investigated in this study.  The results of field surveys and manipulative experiments show a clear relationship between sponge color and light exposure, with sponge color changing along a gradient from orange to yellow to green with increasing light exposure.  In addition, increased growth rates of sponge tissues were observed in response to reduced light exposure.  Analyses of sponge pigments confirm the presence of photosynthetic organisms within the sponge matrix although the results do not support the hypothesis that these endobionts are responsible for the observed color variability of this sponge.  Alternatively, the data presented here support the hypothesis that H. panicea color variability may be caused by blue carotenoproteins produced by sponge tissues.  The impacts of color variability on a primary predator of this sponge, Archidoris montereyensis (Archidorididae), were also studied through lab-based diet experiments.  The results of these diet experiments indicate that color variability impacts nudibranch growth, with yellow sponge diets inducing increased growth, and may also impact reproduction in A. montereyensis.