Deep-water rhodolith bed from central Brazilian continental shelf, Campos Basin: coralline algal and faunal taxonomic composition

Tâmega, Frederico Tapajós de Souza; Bassi, Davide; Figueiredo, Márcia Feijão de; Cherkinsky, Alexander

doi:10.3755/galaxea.16.21

Cited by 14 publications

(4 citation statements)

References 60 publications

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“…Because they are more distant from the coast, it is suggested that they suffer less influence from sedimentation, allowing for the greater penetration of light and providing more favorable conditions for CCA development in relation to the abundance and dimensions. On the other hand, at outer shelf sites, higher depths may become a CCA limiting growth factor (slowing their growth) once light penetration reduces concomitantly with deep increase [46]. In our study, the rhodoliths from 50 m depth were smaller (~4 cm) than those sampled at the south of ESCS (ca.…”

Section: Discussioncontrasting

confidence: 54%

Structure of Rhodolith Beds and Surrounding Habitats at the Doce River Shelf (Brazil)

et al. 2020

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The world's largest rhodolith beds have been reported from the Brazilian continental shelf. Highly biodiverse beds are located in Southeast Brazil, but ecological aspects of these beds remain unknown. Despite their ecological importance, rhodolith beds (RBs) have recently been subjected to a severe threat, when more than 35 million cubic meters of mining residues slid down a mountainside on 5 November 2015, after a collapse of a gigantic dam upstream (the Mariana disaster), causing a huge impact on the Doce River. Our aim is to assess rhodolith beds and adjacent coralline formations on the Doce River Shelf (DRS) after the dam collapse. This paper describes the distribution, abundance, vitality, size and shape, as well as unmapped bryozoan rich sediment formations in this area, serving as baseline knowledge for environmental monitoring. Four distinct biogenic sea bottom habitats (bryozoan bottoms, rhodolith beds, carbonate concretions, and reefs) were recognized at different depth ranges with distribution indicated to be mostly related to the local sedimentary regime. Mud sediments dominated the seafloor up to 35 m depth. On the mid shelf, bryozoan bottoms were recorded from 35 to 45 m depth. Crustose coralline algae (CCA) occurring as rhodoliths and carbonate concretions extend over 1953 km 2 in the mid and outer shelf. Rhodolith beds predominate in these areas, totaling 1521 km 2 of sea bottom and were more abundant at depths between 45 and 65 m, occupying an extensive area south of the Doce River mouth. Northward, rhodolith beds are less abundant or absent likely due to the long-term deposition of fine sediments in this region. Carbonate concretions and reefs covered by CCA occupy sparse areas on the outer shelf (65-105 m depth). Differences in rhodolith features recorded, including coverage, density and size, may be related to the Doce River sedimentation and related factors (e.g., hydrodynamics, depth, and light). However, since there are no previous detailed studies on RBs along the DRS, we could not assess the impact of sedimentation of dam wastes on RBs' abundance and density. In any case, these are valuable results for the further monitoring of long-term effects. Considering that the growth of these rhodoliths is relatively slow, and that they are affected by the sedimentation from the Doce River, the implementation of a management and conservation plan for this area is necessary in order to preserve this ecosystem.

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Section: Discussioncontrasting

confidence: 54%

Structure of Rhodolith Beds and Surrounding Habitats at the Doce River Shelf (Brazil)

et al. 2020

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“…Indeed, the Northern sector middle and outer shelf present several carbonate bioconstructions fields (Cavalcanti et al, 2012;Reis et al, 2013). These massive structures are similar to the rhodolith and coralline algae reef patches observed at Campos (Lopes et al, 2014;Tâmega et al, 2014;Figueiredo Jr. et al, 2016;Curbelo-Fernandez et al, 2017) and Espírito Santo (Bastos et al, 2015;Vieira et al, 2019;Oliveira et al, 2020) basins, including aggregates, terraces, pinnacles, rhodoliths mounds, crustose calcareous algae, bryozoans, gastropods, bivalves, and others, creating a rough relief in the ocean bottom (Figures 3I and 5II).…”

Section: Discussionmentioning

confidence: 81%

Santos Basin continental shelf morphology, sedimentology, and slope sediment distribution

2023

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The ocean bottom morphology, depth, sediment grain size, sediment sorting, carbonate content, and water depth are used to compose seafloor maps as support for biological studies. Sediments are reworked by waves and currents and accumulate according to the hydrodynamic level on the continental shelf. In contrast, sediments are accumulated by pelagic settling, mass wasting, turbidity flows, and boundary currents on the slope. Sea level oscillations during the Quaternary also played an important role in modifying the shelf seabed's morphology and sedimentary mosaic composition. The work addresses these topics in the Santos Basin based on extensive bathymetric data, shallow seismic records, and stratified bottom sediment samples in water depths ranging from 25 to 2,400m, as part of The Santos Basin Regional Environmental Characterization Project (PCR-BS). The main objective is to provide broad background information on the sedimentology and morphology of Santos Basin, focusing on the continental shelf. The morphology, sediment supply, shelf orientation, and ocean climate imprint the Santos Basin's characteristics. The Northern shelf sector is the most dynamic because of the narrow shelf, steep gradient, and East-West shoreline orientation, providing conditions for storm waves to approach and mobilize sediment in the ocean bottom shallow than 50 m water depth. The Southern sector of the shelf is much broader than the Northern sector; it displays a gentler gradient, and its orientation is Northeast-Southwest; therefore, less subject to storm waves than the Northern sector.

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“…More than an additional range extension record for one of hundreds of thousands "worm" species, N. maiteae is an emblematic example of the incipient knowledge about the biodiversity of Southwestern Atlantic rhodolith beds. Conversely, research and discovery of hydrocarbon exploitation fields rapidly increased in the last decade, especially in the mesophotic habitats of this region (e.g., Moura et al, 2013), many of those in rhodolith beds such as Peregrino oil field, Campos Basin (Tâmega et al, 2013(Tâmega et al, , 2014, the area where N. maiteae was discovered. Offshore drilling increases the concentration of suspended particles (Patin, 1999), with well-established negative effects over the health of crustose coralline algae (e.g., Reynier et al, 2015) and communitywide changes from sedimentation and contamination (Patin, 1999).…”

Section: Marine Diversitymentioning

confidence: 98%

Environmental licensing on rhodolith beds: insights from a worm

Santos

Lino

Veras

et al. 2016

Natureza & Conservação

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Deep-water rhodolith bed from central Brazilian continental shelf, Campos Basin: coralline algal and faunal taxonomic composition

Cited by 14 publications

References 60 publications

Structure of Rhodolith Beds and Surrounding Habitats at the Doce River Shelf (Brazil)

Structure of Rhodolith Beds and Surrounding Habitats at the Doce River Shelf (Brazil)

Santos Basin continental shelf morphology, sedimentology, and slope sediment distribution

Environmental licensing on rhodolith beds: insights from a worm

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