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Reefs are the richest marine ecosystems. Their benthic communities generate structural complexity and participate in nutrient cycles, providing habitat and food for many marine species. These ecosystems have been threatened by local and global anthropogenic impacts and changes in community structure have led to loss of biodiversity, ecosystem function and services worldwide. Most studies about these structural changes have been conducted in Caribbean and Indo-Pacific coral reefs. In the Southwestern Atlantic, where reefs are naturally algae-dominated, these efforts are incipient, especially at oceanic islands where local anthropic impacts tend to be lower, and natural and climate-induced fluctuations might be easily detected. We conducted the first temporal assessment of benthic communities and the influence of oceanographic parameters between 2013 and 2019 in Fernando de Noronha (FNA), the largest Brazilian oceanic archipelago. We annually sampled benthic communities in FNA’s shallow reefs (2–21 m) using photoquadrats, quantified and gathered organisms in major groups according to their functional roles. We also characterized and tested “sea surface temperature,” “marine heatwaves,” “diffuse attenuation coefficient,” and “wave energy” influence for the same period. The most abundant groups were epilithic algal matrix (EAM; mean annual coverage: 23–60%), macroalgae (15–35%) and calcifiers (15–29%), followed by cyanobacteria (1–37%), suspension/filter-feeders (

Brazil has a strong tradition in fisheries and is consequently affected by the impacts of this activity. Fishing-related debris, as abandoned, lost or otherwise discarded fishing gear (ALDFG) is an example of indirect impact. While reports on ALDFG are becoming more frequent worldwide, Brazil is still deficient in this information. The main objective of the present study was to review the knowledge on ALDFG in the country, as a contribution to the management of marine debris from fishing. The study also sought to investigate the number of scientific studies that report ALDFG, what sites were sampled and what are the knowledge gaps in this subject. An extensive literature review was carried out to obtain detailed information. Thirty-two studies were obtained from different fields of research reporting the presence of ALDFG in Brazil, with only nine focusing specifically on this topic. The most recorded items were nets, ropes and fishing lines found on beaches, submerged in coastal areas and in oceanic islands. The reports of ALDFG covered 12 of the 17 Brazilian coastal states, with significant presence of debris within protected areas. Overall there were few studies on the subject in Brazil. There are knowledge gaps regarding ALDFG in regions with depths greater than 45 m and distant 12 nautical miles from the coast, and regarding indirect impacts of ALDFG, such as habitat changes. Thus, more studies and actions are needed to minimize the occurrence of ALDFG in Brazil and to guarantee its inclusion in monitoring and management actions of protected areas.

As marine ecosystems are influenced by global and regional processes, standardized information on community structure has become crucial for assessing broad-scale responses to natural and anthropogenic disturbances. Extensive biogeographic provinces, such as the Brazilian Province in the southwest Atlantic, present numerous theoretical and methodological challenges for understanding community patterns on a macroecological scale. In particular, the Brazilian Province is composed of a complex system of heterogeneous reefs and a few offshore islands, with contrasting histories and geophysical-chemical environments. Despite the large extent of the Brazilian Province (almost 8,000 kilometers), most studies of shallow benthic communities are qualitative surveys and/or have been geographically restricted. We quantified community structure of shallow reef habitats from 0° to 27°S latitude using a standard photographic quadrat technique. Percent cover data indicated that benthic communities of Brazilian reefs were dominated by algal turfs and frondose macroalgae, with low percent cover of reef-building corals. Community composition differed significantly among localities, mostly because of their macroalgal abundance, despite reef type or geographic region, with no evident latitudinal pattern. Benthic diversity was lower in the tropics, contrary to the general latitudinal diversity gradient pattern. Richness peaked at mid-latitudes, between 20°S to 23°S, where it was ~3.5-fold higher than localities with the lowest richness. This study provides the first large-scale description of benthic communities along the southwestern Atlantic, providing a baseline for macroecological comparisons and evaluation of future impacts. Moreover, the new understanding of richness distribution along Brazilian reefs will contribute to conservation planning efforts, such as management strategies and the spatial prioritization for the creation of new marine protected areas.

High sedimentation is often related to stress in coral reef communities. Most southwestern Atlantic reefs are characterized by high sedimentation. However, there are no temporal series of sediment deposition rates. We evaluated sediment deposition, the sediment carbonate composition and coral and zoanthid covers on six reefs in Brazil over four-years. Sediment deposition rates varied from near zero to 233 mg cm-2 day-1, with peaks between August and December, and yearly averages ranging from nine to 104 mg cm-2 day-1. Deposition rates presented site-specific correlations with wind, indicating that resuspension must be a major factor. The presence of carbonates varied from 38% to 90%, with two sites showing seasonal differences. Benthic communities were fairly similar among sites, but the analyses suggested particular frequencies at each site. There was no significant correlation between sediment and benthic communities. However, Palythoa caribaeorum usually occur in high sediment deposition areas. Our results did not corroborate previous data that suggested that a 10 mg cm-2 day-1 would be a "critical limit for coral survival". Some coral reefs may be associated with high sedimentation environments including carbonatic fractions, but which does not per se hinder the development of southwestern Atlantic coral reef communities.A sedimentação é freqüentemente relacionada a estresse em recifes de coral. Os recifes do Atlântico sul ocidental possuem grande sedimentação, entretanto carecem de séries temporais das taxas de deposição de sedimento. Foram avaliadas estas taxas e a composição carbonática do sedimento, além da cobertura de corais e zoantídeos em seis recifes brasileiros durante quatro anos consecutivos. A deposição variou de zero a 233 mg cm-2 dia-1, com picos entre agosto e dezembro e médias anuais variando de nove a 104 mg cm-2 dia-1. As taxas de deposição apresentaram correlação com o vento, indicando que a ressuspensão deve ser o fator preponderante. A contribuição do carbonato variou de 38% a 90%, com dois locais apresentando diferenciação sazonal. As comunidades bênticas foram similares entre locais, entretanto as análises sugerem freqüencias diferenciadas para cada local. Não houve correlação significativa entre sedimentação e a comunidade bêntica. Entretanto, maior cobertura de Palythoa caribaeorum normalmente ocorreu em áreas de maior sedimentação. Nossos resultados não corroboraram resultados prévios sugerindo que 10 mg cm-2 dia-1 seria "limite crítico para sobrevivência" dos corais. Recifes brasileiros podem estar associados a ambientes de alta deposição de sedimento com elevadas frações carbonáticas, o que não impede o desenvolvimento das comunidades recifais do Atlântico sul ocidental.

Sedimentation has previously been considered an important source of impact in coral reefs. We compared 3 sites on the Abrolhos Bank, Brazil, regarding sedimentation rates, carbonate sediment composition, coral cover, and colony size for the commonest local coral species (Mussismilia braziliensis, Siderastrea stellata, and Favia gravida). The sites are located at different distances from the mainland: Pedra de Leste (14 km), Pontas Sul (26 km), and Parcel dos Abrolhos (58 km). Sedimentation was higher in winter (p A sedimentação tem sido considerada uma importante fonte de impacto nos recifes de coral. Uma comparação entre as taxas de sedimentação, teor de carbonatos nos sedimentos, cobertura coralínea e tamanho de colônias de corais para as espécies mais comuns (Mussismilia braziliensis, Siderastrea stellata, e Favia gravida) foi realizada em 3 locais no Banco dos Abrolhos. Os locais representam um gradiente de distância da costa: Pedra de Leste (14 km), Pontas Sul (26 km) e Parcel dos Abrolhos (58 km). A sedimentação foi maior no inverno (p

The first study on coexistence of reef benthic organisms in Brazilian coral reefs was done in three localities of the Abrolhos Archipelago. Organisms were recorded in concentric circle samples (10 and 20 cm in diameter) randomly laid on transects. Type and frequency of "coexistence events" between pairs of organisms were determined. Most frequent organisms (massive and branched coralline algae, Favia gravida, and Agaricia agaricites) also had many significant positive coexistence events. These results might be related to the abundances of these organisms. The most frequent coral (Siderastrea stellata), however, exhibited only a few significant coexistence events (9% of 32 tests). Since the great majority of events were positive, and since there was high variation in the species/groups involved in significant events in different localities, benthic communities of Abrolhos Archipelago may well be structured primarily by abiotic rather than biotic factors.Se hizo el primer estudio de coexistencia de organismos bénticos de arrecifes brasileños en tres localidades del Archipiélago de Abrolhos, registrando la presencia de organismos en círculos de 10 y 20 cm de diametro, distribuidos al azar en transectos. La mayoría de los organismo frecuentes (algas coralinas macizas y ramificadas, Favia gravida y Agaricia agaricites) mostraron la más alta "coexistencia positiva", tal vez por su abundancia. El coral más frecuente (Siderastrea stellata), sin embargo, mostró apenas algunos eventos de coexistencia significativos (9% de 32 ensayos). Debido a que la mayor parte de los eventos fue positiva, y considerando que existe una alta variabilidad en las interacciones significativas en diferentes localidades, las comunidades bénticas del Archipiélago de Abrolhos pueden haber sido estructuradas principalmente por factores abióticos, mas que por factores bióticos.