Title

Field biology of Halimeda tuna (Bryopsidales, Chlorophyta) across a depth gradient: comparative growth, survivorship, recruitment, and reproduction

Authors

Authors

P. S. Vroom; C. M. Smith; J. A. Coyer; L. J. Walters; C. L. Hunter; K. S. Beach;J. E. Smith

Comments

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Abbreviated Journal Title

Hydrobiologia

Keywords

Halimeda tuna; coral reef; alizarin; Florida Keys; Ericthonius; brasiliensis; Dictyota; GREEN-ALGA-HALIMEDA; GREAT-BARRIER-REEF; SAN-SALVADOR ISLAND; CORAL-REEFS; FLORIDA-KEYS; SPECIES COMPOSITION; UNCHARTED SEAMOUNT; WATER; CALCIFICATION; CAULERPALES; Marine & Freshwater Biology

Abstract

Growth, survivorship, recruitment, and reproduction of Halimeda tuna, a dominant green alga in many reef systems of the Florida Keys, were monitored at a shallow back reef ( 4 - 7m) and deep reef slope ( 15 - 22 m) on Conch Reef. Despite lower light intensities and similar grazing pressures, amphipod infestations, and epiphyte loads at both sites, the deeper site exhibited significantly higher growth rates in summer months over a 4-year period than found for the shallow population, possibly because of higher nutrient levels at depth and photoinhibition of shallow plants. Sexual reproductive events occurred simultaneously across the entire reef, with up to 5% of the population at both sites developing gametangia. New upright axes formed from zygotes, asexual fragmentation, or vegetative runners. Plants appear to have persistent basal stumps that survive harsh environmental conditions, even if upright, photosynthetic axes are removed. Sexual reproduction and 'smothering' by epiphyte overgrowth are hypothesized to be two causes of death for individuals.

Journal Title

Hydrobiologia

Volume

501

Issue/Number

1-3

Publication Date

1-1-2003

Document Type

Article

Language

English

First Page

149

Last Page

166

WOS Identifier

WOS:000186041800016

ISSN

0018-8158

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