Structure of rhodolith beds from 4 to 55 meters deep along the southern coast of Espírito Santo State, Brazil

Abstract

Rhodoliths are one of the most extensive benthic communities of the Brazilian continental shelf, but their structure is poorly known. The richest marine flora of Brazil´ s coastal zone is found in Espírito Santo State and its diversity has been partly associated with the presence of extensive areas of rhodoliths, extending from the intertidal zone to 120 m across the continental shelf. One species of kelp, Laminaria abyssalis, is endemic to this area and occurs between 45 and 120 m depth. Our objective was to determine the density and physical dimensions of the superficial rhodoliths between 4 and 55 m depth in the southern region of Espírito Santo State. The study area was 3 to 45 km offshore. Samples were obtained in 2004 and 2005 by Scuba diving in three depth zones: 4–18 m, 25–30 m and 50–55 m. Transect lines and video images were used to determine rhodolith density. The diameter and sphericity of at least 60 individuals from each zone were measured. Rhodolith size increased and density decreased from the shallow to the deeper zones. Spheroidal was the typical shape throughout the depth zones. Five rhodolith-forming genera were identified: Lithothamnion, Lithophyllum, Hydrolithon, Neogoniolithon and Sporolithon. Epibenthic biomass and species richness over the rhodolith bed in the shallow zone was lowest in winter, likely the result of disturbance caused by typical winter storms. Changes in light and temperature are probably the most important factors in the changes observed in the rhodolith beds from the deepest zones.

Seaweed diversity associated with a Brazilian tropical rhodolith bed

“…2006, Amado-Filho et al 2007). En un estudio reciente, Amado-Filho et al (2007) observaron un aumento en la talla de rodolitos individuales ( fig.…”

“…In a recent study, Amado-Filho et al (2007) showed that individual rhodoliths ( fig. 1b) occurring from 4 to 55 m depth along the southern coast of Espírito Santo increased in size and their density decreased from the shallow to the deeper zones; however, studies are required to determine how this rhodolith distribution Los rodolitos, las formas de vida libre de varios géneros de algas coralinas no geniculadas, también han sido reconocidos como especies fundamentales (Amado-Filho et al 2007, Foster et al 2007). La diversidad de los organismos que viven sobre los rodolitos probablemente sea resultado de que proporcionan superficies duras para la fijación (Foster et al 2007).…”

“…Its high diversity has been associated, in part, with the presence of extensive rhodolith beds ( fig. 1a) extending from the intertidal zone down to 100 m depth (Horta et al 2001, Guimarães 2006, Amado-Filho et al 2007. In a recent study, Amado-Filho et al (2007) showed that individual rhodoliths ( fig.…”

“…1a) extending from the intertidal zone down to 100 m depth (Horta et al 2001, Guimarães 2006, Amado-Filho et al 2007. In a recent study, Amado-Filho et al (2007) showed that individual rhodoliths ( fig. 1b) occurring from 4 to 55 m depth along the southern coast of Espírito Santo increased in size and their density decreased from the shallow to the deeper zones; however, studies are required to determine how this rhodolith distribution Los rodolitos, las formas de vida libre de varios géneros de algas coralinas no geniculadas, también han sido reconocidos como especies fundamentales (Amado-Filho et al 2007, Foster et al 2007).…”

“…Consecuentemente, las especies fundamentales deben considerarse elementos importantes en los procesos de conservación de la diversidad (Boogert et al 2006, Foster et al 2007. Rhodoliths, the free-living forms of a number of nongeniculate coralline algal genera, have also been recognized as foundation species (Amado-Filho et al 2007, Foster et al 2007. The diversity of organisms living on rhodoliths results from the provision of hard attachment surfaces (Foster et al 2007).…”