Publication Date
Spring 2025
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Moss Landing Marine Laboratories
Advisor
Amanda Kahn; Sally Leys; Thomas Connolly
Abstract
Sponges (Phylum Porifera) are suspension feeders whose water filtration is important to benthic ecosystems because of their conversion of large amounts of dissolved carbon and nitrogen into particulate waste available for detritivores. Sponges filter water by drawing it through a complex aquiferous system of canals and pores. Rhythmic contractions of tissue, which temporarily constrict canals and reduce body size, can diminish filtration rates and therefore affect ecosystem services; however, the physiological function of rhythmic contractions is not completely understood. I recorded long-term time-lapses of the demosponges Tethya californiana and Hymeniacidon perlevis to determine the endogenous and environmental factors that influence rhythmic contractions. I found that contractions occurred simultaneously in the osculum, ostia, and whole body in T. californiana. In H. perlevis, contractions originated and spread between many different oscula, with no evidence of cohesive whole-body behaviour. In T. californiana, duration of rhythmic contractions were significantly correlated with body size, oceanographic season, and dissolved oxygen. Both species reduced contraction frequency and increased total time expanded in seawater enriched with Rhodomonas sp. microalgae. This thesis provides support for rhythmic contractions in sponges as products of both endogenous and environmental factors, improving our understanding of the complexity of behaviours in early-diverging aneural metazoans.
Recommended Citation
Guillas, Keenan C., "Drivers Of Rhythmic Contractions In The Temperate Demosponges Tethya Californiana And Hymeniacidon Perlevis" (2025). Master's Theses. 5648.
DOI: https://doi.org/10.31979/etd.dvj3-3d8c
https://scholarworks.sjsu.edu/etd_theses/5648
