FRONTISPIECE.—Carrie Bow Cay reef complex, aerial photo mosaic, March 1976. SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES -NUMBER 12 The Atlantic Barrier Reef Ecosystem at Carrie Bow Cay, Belize, I STRUCTURE AND COMMUNITIES Klaus Riitzler and Ian G. Macintyre EDITORS ISSUED JUN1019K MTHSONIAN PUBLICATIONS SMITHSONIAN INSTITUTION PRESS City of Washington 1982 ABSTRACT Riitzler, Klaus, and Ian G. Macintyre, editors. The Atlantic Barrier Reef Ecosystem at Carrie Bow Cay, Belize, I: Structure and Communities. Smith sonian Contributions to the Marine Sciences, number 12, 539 pages, frontispiece, 232 figures, 5 plates, 47 tables, 1982.—The results of the first series of multidisciplinary investigations of the Caribbean barrier reef complex near Carrie Bow Cay, Belize, are reported in 34 papers in this volume, which begins with a summary of past work on the Belizean reefs and cays. The first section treats the structure of barrier reef habitats in the vicinity of Carrie Bow Cay, influential physical parameters such as tides and currents, geological and sedimentological history of lagoon, reef, and island substrates, and the island's environment, including its climate and the effects of hurricanes. Subsequent papers analyze the distribution of endolithic microorganisms in carbonate substrates, and the diversity, standing crop, and production in selected lagoon and back-reef habitats. Related contributions report on the benthos of an unusual submarine cave and on the surface zooplankton over reef and lagoon bottoms. One section is devoted to the systematics and local distribution of flora and fauna. Marine plants covered are plankton diatoms, benthic algae—including a detailed study of the red alga Polysiphonia—and sea grasses. Faunistic studies focus on hydroids, medusae, stony corals, octo- corals, sipunculans, anthurid isopods, pycnogonids, a marine chironomid, ophiuroids, and crinoids. In the papers on Polysiphonia, hydroids, stony corals, and anthurids, all species are illustrated for identification by nonspecialists; figures of important or unusual examples are shown in the other systematic contributions. New species are described among anthurids, pycnogonids, and ophiuroids. A section on ecological responses discusses the reaction of algae to grazing pressure, the life history of an ichthyo-parasitic hydroid, the growth response of the reef coral Montastrea annularis to a light gradient, and associa tions between zoanthids and their sponge hosts. Included in this section are discussions of the ecology of the zoanthid Isaurus duchassaingi, settlement behavior and development of the bivalve Malleus candeanus, and behavioral ecology of two closely related reef fishes, genus Acanthemblemana. The volume concludes with two general surveys of the barrier reef and cays, which discuss the Carrie Bow reef section and cay in relation to the overall barrier reef complex. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. Library of Congress Cataloging in Publication Data The Atlantic barrier reef ecosystem at Carrie Bow Cay, Belize. (Smithsonian contributions to the marine sciences ; no. 12) Bibliography: p. Contents: 1. Structure and communities. 1. Coral reef ecology—Belize—Carrie Bow Cay. 2. Carrie Bow Cay (Belize) I. Riitzler, Klaus. II. Macintyre, Ian G. III. Series. QH108.B43A87 574.5'26367'097282 81-607039 AACR2 Contents Page FOREWORD ix Porter M. Kier PREFACE x INTRODUCTION 1 Klaus Riitzler and Ian G. Macintyre Topography, Bio-Geological Structure, and Physical Environment THE HABITAT DISTRIBUTION AND COMMUNITY STRUCTURE OF THE BARRIER REEF COMPLEX AT CARRIE Bow CAY, BELIZE 9 Klaus Riitzler and Ian G. Macintyre TIDES AT CARRIE Bow CAY, BELIZE 47 Bjorn Kjerfve, Klaus Riitzler, and George H. Kierspe WATER CURRENTS ADJACENT TO CARRIE Bow CAY, BELIZE 53 Jeffrey E. Greer and Bjorn Kjerfve WATER EXCHANGE ACROSS THE REEF CREST AT CARRIE Bow CAY, BELIZE 59 Bjorn Kjerfve GEOLOGY AND SEDIMENT ACCUMULATION RATES AT CARRIE Bow CAY, BELIZE 63 Eugene A. Shinn, J. Harold Hudson, Robert B. Halley, Barbara Lidz, Daniel M. Robbin, and Ian G. Macintyre TERRESTRIAL ENVIRONMENT AND CLIMATE, CARRIE Bow CAY, BELIZE .. 77 Klaus Riitzler and Joan D. Ferraris Benthic and Planktonic Communities DISTRIBUTION OF MICROBORERS WITHIN PLANTED SUBSTRATES ALONG A BARRIER REEF TRANSECT, CARRIE Bow CAY, BELIZE 93 Jeffrey A. May, Ian G. Macintyre, and Ronald D. Perkins PRODUCTION OF SOME BENTHIC COMMUNITIES AT CARRIE Bow CAY, BELIZE 109 Paul E. Hargraves MACROBENTHIC INVERTEBRATES IN BARE SAND AND SEAGRASS {Thalassia testudinum) AT CARRIE Bow CAY, BELIZE 115 David K. Young and Martha W. Young A SUBMARINE CAVE NEAR COLUMBUS CAY, BELIZE: A BIZARRE CRYPTIC HABITAT 127 Ian G. Macintyre, Klaus Riitzler, James N. Norris, and Kristian Fauchald v VI SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES SURFACE ZOOPLANKTON AT CARRIE Bow CAY, BELIZE 143 Joan D. Ferraris Diversity and Distribution of Flora and Fauna PLANKTON DIATOMS (BACILLARIOPHYCEAE) FROM CARRIE Bow CAY, BELIZE 153 Paul E. Hargraves MARINE ALGAE AND SEAGRASSES FROM CARRIE Bow CAY, BELIZE 167 James N. Norris and Katina E. Bucher THE RED ALGA Polysiphonia GREVILLE (RHODOMELACEAE) FROM CARRIE Bow CAY AND VICINITY, BELIZE 225 Donald F. Kapraun and James N. Norris HYDROIDEA (CNIDARIA: HYDROZOA) FROM CARRIE Bow CAY, BELIZE ... 239 Barry W. Spracklin MEDUSAE (CNIDARIA) FROM CARRIE Bow CAY, BELIZE 253 Ronald J. Larson STONY CORALS (CNIDARIA: HYDROZOA, SCLERACTINIA) OF CARRIE Bow CAY, BELIZE 271 Stephen D. Cairns OCTOCORALLIA (CNIDARIA) FROM CARRIE Bow CAY, BELIZE 303 Katherine Muzik DISTRIBUTION OF SIPUNCULA IN THE CORAL REEF COMMUNITY, CARRIE Bow CAY, BELIZE 311 Mary E. Rice and Ian G. Macintyre ANTHURIDEA (CRUSTACEA: ISOPODA) OF CARRIE Bow CAY, BELIZE 321 Brian Kensley PYCNOGONIDA FROM CARRIE Bow CAY, BELIZE 355 C. Allan Child Pontomyia EDWARDS (DIPTERA: CHIRONOMIDAE), A MEMBER OF THE CORAL REEF COMMUNITY AT CARRIE Bow CAY, BELIZE 381 Gemot Bretschko OPHIUROIDEA (ECHINODERMATA) FROM CARRIE Bow CAY, BELIZE 387 Frederick H.C. Hotchkiss SHALLOW-WATER CRINOIDEA (ECHINODERMATA) FROM CARRIE Bow CAY, BELIZE 413 D. Bradford Macurda, Jr. Behavior, Species Interaction, and Responses to the Environment CHEMICAL DEFENSE IN TROPICAL MARINE ALGAE 417 James N. Norris and William Fenical LIFE HISTORY OF THE HYDROMEDUSA Stomotoca pterophylla HAECKEL AND ITS ICHTHYOPARASITIC HYDROID 433 Ronald J. Larson NUMBER 12 vn VARIATION IN GROWTH FORMS OF THE REEF CORAL Montastrea annularis (ELLIS AND SOLANDER): A QUANTITATIVE EVALUATION OF GROWTH RESPONSE TO LIGHT DISTRIBUTION USING COMPUTER SIMULATION .... 441 Richard R. Graus and Ian G. Macintyre SPONGE-ZOANTHID ASSOCIATIONS: FUNCTIONAL INTERACTIONS 465 Sara M. Lewis ON THE ECOLOGY OF Isaurus duchassaingi (ANDRES) (CNIDARIA: ZOANTHI- DEA) FROM SOUTH WATER CAY, BELIZE 475 Kathleen S. Larson and Ronald J. Larson LARVAL SETTLEMENT BEHAVIOR AND SHELL MORPHOLOGY OF Malleus candeanus (d'ORBiGNY)(MoLLUscA: BIVALVIA) 489 Thomas R. Waller and Ian G. Macintyre HABITAT AND RESOURCE PARTITIONING BETWEEN Two SPECIES OF Acan- themblemaria (PISCES: CHAENOPSIDAE) , WITH COMMENTS ON THE CHAOS HYPOTHESIS 499 David W. Greenfield and Theresa A. Greenfield Carrie Bow Cay as Part of the Belizean Barrier Reef Complex RECONNAISSANCE STUDY OF THE GEOMORPHOLOGY AND BENTHIC COM MUNITIES OF THE OUTER BARRIER REEF PLATFORM, BELIZE 509 Randolph B. Burke SPECIES-AREA RELATIONSHIPS ON SMALL ISLANDS: FLORISTIC DATA FROM BELIZEAN SAND CAYS 527 David R. Stoddart and F. Raymond Fosberg PLATES 259 Dedication This volume is dedicated to the 50th anniversary of the Great Barrier Reef Expedition 1928-1929, which pioneered the integration of many science disciplines for the better understanding of the coral reef system Foreword Museum scientists tend to be specialists in a particular discipline and to work alone. Those of us, however, who study living organisms learn sooner or later that we cannot hope to understand our animals and plants fully without some knowledge of the environment in which they exist. We also learn at some point to appreciate the benefits of collaborating with fellow scientists whose disciplinary focus may differ from ours, but whose interests are related to our own through the "environmental" link. That is to say, a great natural ecosystem such as the tropical coral reef draws together researchers of many diverse disciplines. The project "Investigations of Marine Shallow-Water Ecosystems" (IMSWE) off Carrie Bow Cay has done this very thing for many of us at the Smithsonian Institution and elsewhere, and thus we have learned far more about our organisms and their environment than we might have done otherwise. As a result, we are more than enthusiastic about IMSWE's progress. We started with only a few investigators, but as the years have passed we have grown into a multidisciplinary contingent. Needless to say, part of IMSWE's success stems from the efforts of the principal investigator, Klaus Riitzler. He is responsible for the organizing, scheduling, coordinating, and orchestrating. He has done all this with good humor and energy. Of course, such an effort would not have been possible without the support and encouragement of the Belizeans themselves. They love their barrier reef and have high regard for its economic, recreational, and aesthetic value. Recognizing the need for understanding and protecting this precious resource, Belizean officials have approved and assisted our various endeavors since IMSWE's modest beginnings. In particular, Winston Miller, Fisheries Officer, has helped us in every way, as have members of the staff at the Ministry of Trade and Industry (after 1979 the Ministry of Health, Housing, and Coop eratives), and the Ministry of Finance. We all know that research cannot go forward without adequate funding. The Exxon Corporation has provided part of our support, and has done it in a most generous fashion, allowing the scientists to go about their studies independently. This volume thus represents the culmination of research effort and support from many quarters. It is the first of an open report series and serves as the basis for future contributions. It not only "sets the scene" by determining terminology and summarizing our knowledge to date, but it also points out the gaps yet to be closed. We look forward to the next decade. September 1980 Porter M. Kier, Director (1970-1979) National Museum of Natural History Smithsonian Institution ix Preface On a windy, overcast morning of February 1972, we discovered Carrie Bow Cay. Arnfried Antonius and I (K.R.) were on our way from Stann Creek (now Dangriga) to Glover's Reef, looking for the Tobacco Cay passage through the barrier reef. We could already hear the waves pounding the coral crest but neither of two islands in front of us matched our memory of Tobacco Cay, and the crew of the charter boat from Belize City, unfamiliar with southern waters, was uncertain too. The smaller but nearer one of the cays had buildings and a solid dock so we decided to have a closer look. Minutes later we tied up to the concrete pier and walked toward the stately main building. No one was around, except for a few mildly disturbed pelicans, but a weathered sign above the gate to the main porch said "Welcome to Carrie Bow Island." On that memorable day when we first walked around Carrie Bow—a speck of sand covered by about 80 coconut trees overlooking three cottages, two outhouses, and three water tanks—we could not have predicted the developments of the eight years to come. Despite its small size, this island has been the site of a simple but functional laboratory to which more than 70 scientists from 30 institutions have come to study the well-developed reef complex nearby. Records indicate that up to 1927 Carrie Bow Cay, then known as Ellen Caye or Bird Caye, was an uninhabited sanctuary for migrating birds and for sea turtles coming there to lay their eggs. The surrounding reef "abounded with conch, lobster, turtles, and parrot fish, all of which have been depleted by extensive trade in these commodities," according to the historical account of Henry T. A. Bowman, current owner of Carrie Bow Cay. Mr. Bowman bought the island in 1943 and decided to name it after his wife Carrie. "At that time the cay was about twice the size it is now, and was surrounded by mangrove, and had about 75 coconut trees that were planted in the early 1900's. The mangrove, breeding spot for mosquitos, was cleared off in 1944 when [he] decided to build a summer home. Of the original coconut trees only six remain today." Mr. Bowman's account also cites the stresses intro duced by countless storms and hurricanes, which were particularly harsh during the past three decades but whose damage Carrie Bow Cay and the reef have managed to survive. Notwithstanding these changes, the area remains relatively undisturbed by scientific standards, and thus is an ideal location for an ecological study of coral reefs. More significant, it is a segment of an enormous reef complex that is reasonably accessible from major cities on the North American mainland. This volume presents the first extensive scientific account of the barrier reef around Carrie Bow Cay, Belize. It is an outgrowth of the Smithsonian Institution Program "Investigations of Marine Shallow-Water Ecosystems" (IMSWE), which began in 1970 under the guidance of W. H. Adey, A. L. NUMBER 12 Dahl, and the editors of this volume. It was our goal to introduce long-term cooperation and a truly interdisciplinary approach to the ecological study of coral reefs and related tropical environments. Our search for a study site that would be satisfactory to the special requirements of various disciplines led us to the reef off Belize. IMSWE evolved alongside a larger proposed project for the study of a coral-reef ecosystem that was to be a multi-institutional and multi-national program sponsored by the International Decade of Ocean Exploration. Glover's Reef atoll was contemplated as a site for that program's comparative studies and Carrie Bow Cay—although not yet seen by any of the planning committee—was discussed as an additional possibility because of its logistical advantages, particularly its location half way between the mainland of Belize and the atoll. Although the large program was not funded, Smithsonian Institution scientists carried forward the idea for an interdisciplinary study of a coral reef ecosystem. Since that time, many enthusiasts have joined in IMSWE's collaborative investigations. Because of the growing body of information resulting from our work, we are now able to present this volume, whose purpose is to give a general introduction to the topography, oceanography, geology, and biology of the Belizean barrier reef complex near Carrie Bow Cay. Some new terms have been introduced in this volume to describe the physiographic characteristics and zonation of the reef in this area. It is hoped