Form and Internal Structure of Recent Algal Nodules (Rhodolites) from Bermuda

Bosellini, Alfonso; Ginsburg, Robert N.

doi:10.1086/627697

Cited by 226 publications

(98 citation statements)

References 14 publications

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“…An analysis of data for nongeniculate algae revealed very low growth rates, such as 0.4 mm yr -1 for rhodoliths (not identified) from Bermuda (Bosellini and Ginsburg, 1971) and 0.01-0.05 mm yr -1 for Lithophyllum sp. (Littler et al, 1991).…”

Section: Discussionmentioning

confidence: 99%

“…Foster (2001) mentions that research on the age and growth of rhodolith species is lacking, and that what is known is based on doubtful methods of difficult validation. Regarding differential deposition, rhodoliths are considered structures for the potential characterization of paleoenvironments (Bosellini and Ginsburg, 1971;Prager and Ginsburg, 1989;Foster et al, 1997). Wehrman (1998) observed light and dark bands in Lithothamnion corallioides (P. & H. Crouan) P. & H. Crouan and in Phymatoliton calcareum (Pallas) Adey & McKibbin, and determined that they represent an annual cycle with higher density of magnesium in the light band and lower in the dark one, the former being deposited in summer and the latter in winter; also, a growth rate of 0.310-0.620 mm yr -1 was indirectly estimated for these species.…”

Section: Introductionmentioning

confidence: 99%

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Age and growth of Lithothamnion muelleri (Corallinales, Rhodophyta) in the southwestern Gulf of California, Mexico

Rivera¹,

Rodríguez²,

Foster

2004

Cienc. Mar.

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ResumenEl alga coralina no geniculada Lithothamnion muelleri Lenormand ex Rosanoff es comúnmente encontrada formando mantos de rodolitos en zonas someras expuestas al oleaje dentro del suroeste del Golfo de California. Esta especie tiene bandas de crecimiento a todo lo largo de las ramas principales del talo que sugieren un crecimiento periódico y que probablemente podrían ser utilizadas para determinar su tasa de crecimiento y edad. Como parte de la investigación que se está desarrollando sobre los mantos de rodolitos y su ecología, se desarrollaron observaciones sobre la naturaleza de esas bandas en la estructura de las plantas y en experimentos de crecimiento en campo y laboratorio. Se marcaron con alizarina plantas individuales de diferentes clases de talla en el campo y otro conjunto de plantas fue al laboratorio llevado para su análisis. La mitad de las plantas fueron muestreadas después de 6 meses y el resto recolectadas a los 12 meses. Los resultados muestran una tasa de crecimiento de 0.60 mm año -1 en el campo y 0.87 mm año -1 en el laboratorio. Los análisis estadísticos mostraron que no existen diferencias significativas entre las ramas de una planta, ni entre plantas de diferentes tamaños. El crecimiento fue estacional, con mayores tasas en invierno y primavera y menores en verano y otoño. Esto puede explicar la alternancia de bandas claras y obscuras (hasta 4) a lo largo de una rama principal. Las tasas de crecimiento sugieren que las plantas más grandes (p.ej. 15 cm de diámetro) podrían tener más de 100 años de antigüedad.Palabras clave: edad, crecimiento, Lithothamnion muelleri, rodolitos, Corallinales. AbstractThe nongeniculate coralline alga Lithothamnion muelleri Lenormand ex Rosanoff is commonly found as a free-living rhodolith in the wave-exposed shallow waters of the southwestern Gulf of California. This species has bands along the main branch axes suggesting that growth is periodic and that may be used to determine age and growth. As part of our ongoing research related to rhodoliths and their ecology, we have made observations on the nature of these bands based on their structure in entire plants and on field and laboratory growth experiments. Individual plants from different size classes were tagged, stained with alizarin and returned to the field, while another set was tested in the laboratory. Half of the plants were sampled after 6 months and the rest after 12 months. The data indicate that this species grew at a rate of 0.60 mm yr -1 in the field and 0.87 mm yr -1 in the laboratory. There were no significant differences among branches within a plant, or among plants of different size. Growth was seasonal, with high rates in winter and spring, and low rates in summer and fall. This may explain the observed alternating light-dark bands (up to 4) along branch axes. The growth rates suggest that larger plants (ca 15 cm diameter) may be over 100 years old.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Age and growth of Lithothamnion muelleri (Corallinales, Rhodophyta) in the southwestern Gulf of California, Mexico

Rivera¹,

Rodríguez²,

Foster

2004

Cienc. Mar.

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“…It is important to indicate that due to the low density of kelp canopy, the estimation of rhodolith density in the deepest zone by video transect was not affected. Rhodolith sphericity has commonly been used as an indicator of frequency of movement (Sneed and Folk 1958, Bosellini and Ginsburg 1971, Bosence 1976 Figura 3. Diagrama de la esfericidad de los rodolitos de las zonas de muestreo 1, 2 y 3; cada punto es la esfericidad de un rodolito.…”

Section: Discussionmentioning

confidence: 99%

“…En Baja California, por ejemplo, se pueden observar densidades dẽ 11,000 rodolitos m -2 (Steller et al 2003), y en La Parguera, Puerto Rico, donde se encuentra un manto monotípico de Ginsburg 1989). Some studies have suggested that rhodolith shape changes from spherical to discoidal in association with a reduction in water motion and, thus, the turning frequency decreases (Bosellini and Ginsburg 1971;Bosence, 1976Bosence, , 1991Prager and Ginsburg 1989). This generally occurs with increasing depth.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2007

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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.

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“…Many investigators have sought to explain the spherical morphology of rhodoliths, generally invoking some hydrological or biological mechanism for frequent turning (FOSTER, 2001). Some studies have suggested that rhodolith shape can change from spherical to discoidal associated with a decreased turning frequency caused by a reduction in water motion (BOSELLINI;GINSBURG, 1971;BOSENCE 1976BOSENCE , 1991PRAGER;GINSBURG, 1989). However, some minimal water motion is required to maintain rhodolith beds and it has been suggested that they require both shelter from wave action to prevent burial of thalli but sufficient movement of the water to prevent smothering with silt (HALL-SPENCER, 1998).…”

Section: Rhodolithsmentioning

confidence: 99%

Rhodolith bed structure along a depth gradient on the northern coast of bahia state, brazil

et al. 2010

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A B S T R A C TThe aim of this study was to determine the structure of a rhodolith bed along a depth gradient of 5 to 25 m in the shelf in front of Salvador City, a region of northeastern Brazil. The dimensions, morphology and coralline algae composition of the rhodoliths were analyzed, as well as the vitality, density, and associated flora of the bed at three depths: 5, 15 and 25 m. Samples were obtained by SCUBA divers in summer 2007. Five rhodolith-forming taxa were identified: Sporolithon episporum, Lithothamnion brasiliense, Lithothamnion superpositum, Mesophyllum erubescens, and Lithophyllum sp. The encrusting growth form and the spherical shape were predominant at all depths. Rhodolith dimensions and vitality decreased and the density increased from the shallow to the deepest zones. Fifty-six macroalgal species were found as rhodolith-associated flora. The shallower depth presented higher values for macroalgal biomass and number of species. These results associated with other recent rhodolith bed descriptions indicate that the pattern of Brazilian rhodolith bed structure along depth gradients may be related to a combination of the extent and slope of the continental shelf. R E S U M OO objetivo deste estudo foi determinar a estrutura de um banco de rodolitos ao longo de um gradiente de profundidade na plataforma em frente à cidade de Salvador, nordeste brasileiro. Foram analisadas as dimensões, a forma e composição das algas calcárias dos rodolitos, bem como a vitalidade, densidade e flora associada ao banco, em três profundidades: 5, 15 e 25 m. As amostras foram obtidas por meio de mergulho autônomo no verão de 2007. Cinco espécies de algas calcárias formadoras de rodolito foram identificadas: Sporolithon episporum, Lithothamnion brasiliense, Lithothamnion superpositum, Mesophyllum erubescens e Lithophyllum sp. A forma de crescimento incrustante e a forma esférica foram predominantes em todas as profundidades. Houve uma redução da dimensão e vitalidade dos rodolitos e um aumento da densidade com a profundidade. Cinqüenta e seis espécies de macroalgas foram encontradas como flora associada aos rodolitos. A profundidade mais rasa apresentou os maiores valores de biomassa e número de espécies de macroalgas. Esses resultados, associados com outras descrições recentes de bancos de rodolitos, indicam que o padrão estrutural desses bancos no Brasil, ao longo de gradientes de profundidade, pode estar relacionado a uma combinação da extensão e da inclinação da plataforma continental.

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Form and Internal Structure of Recent Algal Nodules (Rhodolites) from Bermuda

Cited by 226 publications

References 14 publications

Age and growth of Lithothamnion muelleri (Corallinales, Rhodophyta) in the southwestern Gulf of California, Mexico

Age and growth of Lithothamnion muelleri (Corallinales, Rhodophyta) in the southwestern Gulf of California, Mexico

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

Rhodolith bed structure along a depth gradient on the northern coast of bahia state, brazil

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