HCNSO Student Theses and Dissertations

Copyright Statement

All rights reserved. This publication is intended for use solely by faculty, students, and staff of Nova Southeastern University. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, now known or later developed, including but not limited to photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author or the publisher.

Defense Date


Document Type

Thesis - NSU Access Only

Degree Name

M.S. Marine Biology


Oceanographic Center

First Advisor

Bernhard Riegl

Second Advisor

Alexander Soloviev

Third Advisor

Alison Moulding


Water flow is an important abiotic factor for corals and other cnidarians. This study shows how water flow influences bleaching in Palythoa caribaeorum. Colonies were exposed to flow (low = 3 cm s-1, high = 15 cm s-1) in two temperature regimes (low: 26.5°C, which is within natural variability on the reef where specimens were collected; high: 33.5°C, which is 3.5°C above usual summer temperature) in a unidirectional flume for 48 hours. Two sizes (small = 2.3 ± 0.2 cm, large = 7.3 ± 0.4 cm in diameter) were tested in six repeats per flow regime. Bleaching was determined by zooxanthellae count using a hemocytometer and by chlorophyll a concentration using fluorometry. Results suggest that onset of bleaching is rapid (within 48 hours) in high temperature. The low temperature did not cause significant bleaching. In the high temperature treatment, P. caribaeorum consistently bleached less in high flow. Upstream sides of large colonies bleached less than the downstream sides in high flow. In high flow, small colonies bleached less than large colonies. This suggests that enhanced diffusion of toxic oxygen species is important to mitigate bleaching and is more easily accomplished in small colonies, which may thus have an advantage during bleaching events, as has been observed in the literature.

To access this thesis/dissertation you must have a valid nova.edu OR mynsu.nova.edu email address and create an account for NSUWorks.

Free My Thesis

If you are the author of this work and would like to grant permission to make it openly accessible to all, please click the Free My Thesis button.

  Link to NovaCat