Zelinda Margarida de Andrade Nery Leão

Diseases leading to accelerated decline of reef corals in the largest South Atlantic reef complex (Abrolhos Bank, eastern Brazil)

Although reef corals worldwide have sustained epizootics in recent years, no coral diseases have been observed in the southwestern Atlantic Ocean until now. Here we present an overview of the main types of diseases and their incidence in the largest and richest coral reefs in the South Atlantic (Abrolhos Bank, eastern Brazil). Qualitative observations since the 1980s and regular monitoring since 2001 indicate that coral diseases intensified only recently (2005-2007). Based on estimates of disease prevalence and progression rate, as well as on the growth rate of a major reef-building coral species (the Brazilian-endemic Mussismilia braziliensis), we predict that eastern Brazilian reefs will suffer a massive coral cover decline in the next 50 years, and that M. braziliensis will be nearly extinct in less than a century if the current rate of mortality due to disease is not reversed.

Global environmental changes: setting priorities for Latin American coastal habitats

As the effects of the Global Climate Changes on the costal regions of Central and South Americas advance, there is proportionally little research being made to understand such impacts. This commentary puts forward a series of propositions of strategies to improve performance of Central and South American science and policy making in order to cope with the future impacts of the Global Climate Changes in their coastal habitats.

Use of the video transect method for characterizing the Itacolomis reefs, eastern Brazil

The video-transect method consists of a field survey performed with a video-camera along a line of fixed length, with the registered images further analyzed using a computer. This method was successfully applied in Brazil for the first time in the coral reefs of Todos os Santos Bay. The main goal of this work was to define the minimum sampling effort needed to describe the coral community when the video-transect method was applied to a selected reef site, namely the Pedra do Silva Reef in the Itacolomis reef complex, inside the Corumbau Marine Extractive Reserve, in Southern Bahia. Each transect was analyzed throughout its length, in successive captured video frames. The findings revealed that six 20 m long transects with an analysis of twenty points per image (frame) was sufficient for sampling the broad taxonomic categories of hard corals and major reef benthos, and that the whole field operation could be performed during one dive per station.

Deficit of sand in a sediment transport model favors coral reef development in Brazil.

This paper shows that the location of the shoreface bank reefs along the northeastern and eastern coasts of Brazil, in a first order approximation, seem to be controlled by the deficit of sediment in the coastal system. The sediment transport pattern defined by a numerical modeling of wave refraction diagrams, representing circa 2000 km of the northeastern and eastern coasts of Brazil, permitted the regional-scale reproduction of several drift cells of net longshore sediment transport. Those drift cells can reasonably explain the coastal sections that present sediment surplus or sediment deficit, which correspond, respectively, to regions where there is deposition and erosion or little/no deposition of sand. The sediment deficit allows the exposure and maintenance of rocky substrates to be free of sediment, a favorable condition for the fixation and development of coral larvae.

Characterization of coral bleaching environments and their variation along the Bahia state coast, Brazil

The relation between climate variability and coral bleaching in the Bahia reefs was investigated in an attempt to characterize the bleaching environments. The following 13-year time series were derived from the remote-sensing, analysis and reanalysis data: maximum summertime sea surface temperature (SST), maximum sea surface temperature (MaxSST) accumulated in 5 days (SSTAc5day), diffuse attenuation coefficient for downward irradiance at 490 nm (K 490), rainfall and magnitude of surface wind fields, including the zonal (U) and meridional components. Principal component analysis, non-metric multidimensional scaling (MDS) and cluster and similarity analyses indicate the complex nature of the bleaching patterns and the influence of the strong 1997–1998 El Niño. A significant (global R-value = 0.65; p < 0.01) compounding effect of the reef location and bleaching intensity on the differentiation of bleaching environments was detected. A combination of high SSTAc5day and low K 490 may cause coral bleaching in the northernmost reefs. Evidence clearly points to a scenario where the influence of reef location, bleaching year and intensity may produce a compounded effect that determines the bleaching environments in Bahia.

The Coral Reef Province of Brazil

Abstract On the tropical coast of Brazil, coral reefs are prominent marine ecosystems, forming the largest and richest area of reefs in the southwestern Atlantic Ocean. These reefs are characterized by an unusual growth form of mushroom-shaped pinnacles, formed by a low diversity coral fauna rich in endemic species. The inshore reefs thrive in an environment influenced by a continentally derived intense siliciclastic sediment influx, whereas offshore reefs develop in the carbonate dominated middle and outer continental shelves. The inshore reefs are experiencing increasing degradation due to both natural processes (sea-level oscillations, ENSO events) and anthropogenic impacts, such as an accelerated coastal development, reef nutrification, marine pollution, tourism pressure, overexploitation of reef resources, and overfishing. A lowering of sea level that occurred after 5000 years BP, along the coast of Brazil, affected most coastal habitats, mobilizing the western continent-derived siliciclastic sediment toward the eastern reefs and associated habitats, exposing them to a heavy sedimentation. Coral bleaching events occur in the reefs of Brazil during El-Nino occurrences. Accelerated deforestation of coastal zones for urban development has been causing high influx of sediment to the reefs, mangrove forests, and seagrasses. Tourism pressure is already impacting the most visited areas including the yet still few number of marine protected areas (MPAs), and the number of divers per year is already high enough to be deleterious to the reefs. Extraction of coral fauna for the aquarium trade, overfishing and fishing with explosives in both the artisanal and commercial fisheries, and use of chemicals for indiscriminate catching of aquarium fishes are responsible for the mortality of some components of the reef biota. Effective protection of Brazilian reefs is still minimal, and for certain areas, was virtually nonexistent until the beginning of this century, when an initiative of the Directorate of Protected Areas of the Brazilian Government developed a project for the conservation of coral reefs, expanding its effort to map those found in existing Conservation Units, distributed along the entire coast of Brazil and including nearly all of the country’s oceanic islands.

Marginal coral reefs show high susceptibility to phase shift

Phase shift, resulting from coral reef degradation, has been frequently recorded on reefs in optimal conditions, while marginal reefs were considered more resistant due to few records. Noting the lack of marginal reef phase shift studies, we quantitatively assessed their geographic extent in the Southwest Atlantic. Using metadata and a calculated phase shift index, we identified phase shifts from corals to both zoanthid and macroalgal dominance. Positive correlations existed between phase shift and local human impacts for zoanthids: proximity to human populations >100,000 inhabitants, urbanized surfaces and dredged ports and a negative relationship to the endurance of SST >1 °C above normal. Macroalgal shifts positively correlated to ports and urbanized surfaces, higher latitudes and shore proximity, indicating a possible link to nutrient runoff. The high frequency of these phase shifts suggests greater degradation than reported for Caribbean reefs, suggesting that marginal reefs do not have higher natural resistance to human impacts.