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Abstract

COMPARISONS OF CHEMICALLY MEDIATED MARINE PLANT-HERBIVORE INTERACTIONS ON FLORIDA, CARIBBEAN AND PACIFIC REEFS AND CONSEQUENCES FOR REEF COMMUNITIES

Valerie J. Paul¹, Raphael Ritson-Williams¹, Linda J. Walters², Ilsa B. Kuffner³ and Mikel A. Becerro1,^4
1Smithsonian Marine Station at Fort Pierce
²University of Central Florida
³U.S. Geological Survey
⁴Center for Advanced Studies, Blanes
Bio

Overgrowth of corals by macroalgae and benthic cyanobacteria is of increasing concern on coral reefs worldwide. Algal species that have proliferated in reef habitats often contain natural products that deter generalist herbivores. On reefs in Guam, Florida, and Belize, we determined the palatability of common reef algae to reef fishes. In Belize, we also studied the feeding preferences of the sea urchin Diadema antillarum. Some macroalgae were not eaten by fishes even when left in areas of high herbivory for 1-2 days. Cyanobacteria were not readily consumed by reef fishes. Interspecific variation was observed in the susceptibility of different species of Dictyota, Halimeda, and Caulerpa to herbivory. Diadema antillarum individuals were less discriminating than reef fishes and consumed some of almost all species offered to them. For example, fish were strongly deterred by some brown algal extracts, while the urchins readily consumed them. Herbivorous reef fishes and D. antillarum have different algal preferences (often driven by chemical defenses) and can have differential effects on algal community composition. Fish and urchins can control a mixed community of algae on Caribbean reefs better than either one alone. Due to the macroalgal dominance observed on reefs today, competition between corals and macroalgae is a topic of great interest. Past research has shown that adult corals are very good competitors with macroalgae, but it is at the early life-history stages, as larvae and new recruits, that corals are thought to be inferior competitors. We directly tested this hypothesis in controlled field and laboratory experiments with different species of coral larvae. Species of Lyngbya and Dictyota as well as extracts of some of these species caused either recruitment inhibition or avoidance behavior in coral larvae. On reefs experiencing increased algal abundance, the restocking of adult coral populations may be slowed due to recruitment inhibition caused by algal natural products.

THE SMITHSONIAN MARINE STATION: 35 YEARS OF MARINE RESEARCH IN FLORIDA

Valerie J. Paul, Smithsonian Marine Station at Fort Pierce

The Smithsonian Marine Station (SMS) at Fort Pierce, Florida is a vital link between tropical and temperate ecosystems in a coastal network of marine research stations known as the Smithsonian Marine Science Network. The Smithsonian Marine Station, dedicated to studying the rich diversity of marine life of the Indian River Lagoon and Florida coast, recently observed its 35th year of operation. Research activities at the Station focus on the Smithsonian Institution’s core scientific emphasis of discovering and understanding life’s diversity. Most research projects focus on biodiversity, life histories, and ecology of marine and estuarine organisms, with complementary studies of physical processes related to the marine environment. The insights gained by this research are widely disseminated through publications (over 700 to date) and public presentations, thus contributing to the broader mission of the Smithsonian Institution for the "increase and diffusion of knowledge." The station is located on the Indian River Lagoon (IRL), an estuary extending along one third the length of the east coast of Florida that is widely recognized as one of the most diverse estuaries in North America. This region of Florida’s coast, characterized as a transitional zone where temperate and tropical waters overlap, offers access to a great variety of habitats and an extraordinary diversity of species. To the south of Fort Pierce are Florida Bay and the Florida Keys, the only living tropical coral reefs in the continental United States. The Smithsonian Marine Station combines an excellent field location with well-equipped laboratories and an expert staff to provide a rare platform for research on some of the most diverse and important tropical and temperate marine habitats in the world. Research on long-term changes in biodiversity and ecological communities in response to environmental changes, invasive species, and other human impacts provides a first step towards effective public policy and sustainable resource management.