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

2000

Document Type

Thesis - NSU Access Only

Department

Oceanographic Center

First Advisor

Edward O. Keith

Second Advisor

Robert S. Pomeroy

Third Advisor

James D. Thomas

Abstract

Sessile marine invertebrates often exhibit non-random distributions both horizontally and vertically. The larvae of scleractinian corals settle and metamorphose in response to numerous environmental stimuli including substrate composition and the presence of chemical signals, such as extracts of certain red crustose coralline algae. In this study, seven different substrates common to past research efforts were infused with an extract from the red crustose coralline alga, Hydrolithon boergesenii, and placed on the bottom of the ocean, as were similar plates containing no extract. Substrate plates were deployed during the months following the August 1999 coral-spawning event on a reef near Fort Lauderdale, Florida.

Larvae settled on plates placed on the shoreward side of the reef 2.12 times as often as plates placed on the seaward side of the reef. This difference was significant whether the plates contained algal extracts (p=0.004 by two-way ANOVA) or did not contain algal extracts (P = 0.003 by Two-way ANOVA). Reef location also influenced settling independent of plate composition. Peak settlement was observed on unglazed ceramic tiles on the shoreward side of the reef, while the lowest settlement was observed on glass plates on the shoreward side of the reef. Two-way ANOVA with replication showed significant differences in plate material (P = 0.031), presence or absence of algal extract (P = 0.002), and in the interaction of these variables (P = 0.009). Larvae settled on plates containing the algal extracts 2.60 times as often as plates without algal extract.

Multiple analysis of variance (MANOVA) for the interaction of all variables indicated significant interactions for extract presence (P = 0.002), reef zone location (P = 0.036), and plate material (P = .031). The interactions between algal extract presence and reef zone were also significant (P = 0.009), as were the interactions between plate material and algal extract presence (P = 0.009). Simultaneous MANOVA for all variables was not significant (P = 0.071), probably due to large variation in settling plate composition, variation in the concentration and activity of the algal extracts applied to the plates, as well as variation in the microhabitat across the reef.

Files over 10MB may be slow to open. For best results, right-click and select "Save as..."

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

Share

COinS