Severe Impact and Subsequent Recovery of a Coral Assemblage following the 1997–8 El Niño Event: A 17-Year Study from Bahia, Brazil

Abstract

The coral reefs of northern Bahia evolved in isolation from other Atlantic systems and under conditions of high environmental stress, particularly high turbidity. We have monitored the scleractinian assemblage of four shallow bank reefs (Praia do Forte, Itacimirim, Guarajuba and Abai) annually for 17 years since 1995, collecting quantitative data on diversity and density of coral colonies. As the sampling period included the 1997–8 El Niño event, the most severe on record, for the first time these results allow a quantitative assessment of the long-term impact of this major environmental stressor on such a coral assemblage. After El Niño, most species showed significantly reduced densities of colonies, this decline occurring for the subsequent two years without evidence of any new settlement until 2001. From 2000 to 2007 the species Porites astreoides went unrecorded. Recovery was slow, and multivariate analysis revealed that assemblages had not returned to the pre-El Niño state until 2011. It therefore took 13 years for full recovery of the coral assemblage to occur, which has consequences for reef systems if such El-Niño events become more frequent in the future.

Tolerance of Sponge Assemblages to Temperature Anomalies: Resilience and Proliferation of Sponges following the 1997–8 El-Niño Southern Oscillation

“…Instead, there was an increase in density for both coastal and shallow banks assemblages (Fig. 3) and therefore it appears that demosponges (unlike corals [55]) were unaffected by both the food and temperature stress resulting from the 1997–8 ENSO, or that this perceived feeding disruption does not occur. This might be the result of their ability to feed on organic particle sizes not readily collected by other organisms, particularly pico-plankton [76], [77] or because of the decline of other organisms potentially competing for food (particularly ascidians).…”

“…The 1997–8 ENSO had major negative impacts on coral reefs worldwide [63], [64], [65] and for corals the level of recovery from this large-scale event appears to vary considerably between geographic locations [55], [66], [67], [68], [69], [70], [71]. However, far less is known about the longer-term responses of other non-coral organisms to this large-scale climatic event.…”

“…Annual average salinity varies little (35–36), although within reef-top shallow pools, salinity can range from 35 to 39 (see [52]). The pH of seawater varies only between 8.1 and 8.2, with no clear seasonal patterns (see [54], [55]). The coast is influenced by winds arising from the NE and E during the spring-summer, and winds coming from the SE and E during the autumn-winter season.…”

Linking ecology with social development for tropical aquatic conservation

“…In some reef systems, such as those off the coast of Brazil, high turbidity from siliciclastic sediments (Leão and Kikuchi, ) and abundant plankton (Kelmo and Attrill, ) suggest a different evolutionary history. These ‘muddy water corals’ have a greater dependence on heterotrophy (Anthony, ), which may explain their apparent resilience (Miranda et al ., ).…”

Protocolos para o monitoramento de habitats bentônicos costeiros - Rede de Monitoramento de Habitat Bentônicos Costeiros - ReBentos

“…Na costa leste já existem levantamentos sistemáticos desde o ano de 2000. Todos esses registros indicam que a ocorrência de branqueamento dos corais, no Brasil está relacionada a um aumento anormal da temperatura das águas oceânicas (Migotto, 1997;Castro & Pires, 1999;Dutra, 2000;Costa et al, 2001, Costa et al, 2004Ferreira & Maida, 2006;Leão et al, 2008Leão et al, e 2010Kelmo & Atrill, 2013). A avaliação dos efeitos das variações climáticas sobre a comunidade recifal do Brasil é uma das metas da ReBentos, e uma das estratégias mais utilizadas para medir esses efeitos é avaliar o branqueamento dos corais durante e após a ocorrência de eventos de anomalias térmicas das águas oceânicas.…”