Kelmo F et al. (2014), Differential responses of emergent intertidal c...

ECB-ART-43333

PLoS One 2014 Mar 03;93:e93209. doi: 10.1371/journal.pone.0093209.

Show Gene links Show Anatomy links

Differential responses of emergent intertidal coral reef fauna to a large-scale El-Niño southern oscillation event: sponge and coral resilience.

Kelmo F , Bell JJ , Moraes SS , Gomes Rda C , Mariano-Neto E , Attrill MJ .

Abstract
There is a paucity of information on the impacts of the 1997-8 El Niño event and subsequent climatic episodes on emergent intertidal coral reef assemblages. Given the environmental variability intertidal reefs experience, such reefs may potentially be more resilient to climatic events and provide important insights into the adaptation of reef fauna to future ocean warming. Here we report the results of a 17-year (1995-2011) biodiversity survey of four emergent coral reef ecosystems in Bahia, Brazil, to assess the impact of a major El Niño event on the reef fauna, and determine any subsequent recovery. The densities of two species of coral, Favia gravida and Siderastrea stellata, did not vary significantly across the survey period, indicating a high degree of tolerance to the El Niño associated stress. However, there were marked decreases in the diversity of other taxa. Molluscs, bryozoans and ascidians suffered severe declines in diversity and abundance and had not recovered to pre-El Niño levels by the end of the study. Echinoderms were reduced to a single species in 1999, Echinometra lucunter, although diversity levels had recovered by 2002. Sponge assemblages were not impacted by the 1997-8 event and their densities had increased by the study end. Multivariate analysis indicated that a stable invertebrate community had re-established on the reefs after the El Niño event, but it has a different overall composition to the pre-El Niño community. It is unclear if community recovery will continue given more time, but our study highlights that any increase in the frequency of large-scale climatic events to more than one a decade is likely to result in a persistent lower-diversity state. Our results also suggest some coral and sponge species are particularly resilient to the El Niño-associated stress and therefore represent suitable models to investigate temperature adaptation in reef organisms.

PubMed ID: 24675785
PMC ID: PMC3968116
Article link: PLoS One

Genes referenced: impact LOC115925415

Article Images: [+] show captions

	Figure 1. Assemblage metrics from faunal surveys across coastal emergent reefs in Bahia.(A) all invertebrates, (B) corals, (C) molluscs (D) bryozoans, (E) ascidians, (F) cnidarians, (G) echinoderms, (H) sponges. • Density, ▪ Species Richness (additional y-axis). Coloured bars indicate the period of stress.
	Figure 2. Proportion (%) of coral bleaching and mortality of the scleractinian species from the emergent intertidal reefs of Northern Bahia throughout the 17-year investigation: (A) coral bleaching and (B) coral mortality; (▪) Siderastrea stellata and (•) Favia gravida (additional y-axis).Coloured bars indicate the period of stress.
	Figure 3. MDS ordinations of the reef-associated invertebrate community data from the emergent intertidal reefs from northern Bahia throughout the sampling period, 1995–2011, based on [ln (x + 1)] transformed species densities and Bray Curtis similarities.(A) ascidians; (B) bryozoans; (C) cnidarians; (D) echinoderms; (E) molluscs; (F) sponges.
	Figure 4. MDS ordination of the reef-associated invertebrate assemblage data from the emergent intertidal reefs in northern Bahia throughout the sampling period, 1995–2011, based on [ln (x + 1)] transformed species densities and Bray Curtis similarities (Average dissimilarity: pre-ENSO×ENSO = 21.86; pre-ENSO×Post-ENSO = 21.24; ENSO×Post-ENSO = 28.18).Arrows indicate the direction of change.
	Figure 5. Opportunistic behaviour of Echinometra lucunter on the emergent intertidal reefs from northern Bahia after the 1997–8 ENSO event.(A) The reef top of Itacimirim before the ENSO event (April 1996). (B) The same reef area one year after the end of the stress period (April 1999). (C) A quadrat showing the coastal emergent reef top of Praia do Forte before the ENSO event (April 1996). (D) A quadrat of the reef top of Praia do Forte one year after the end of ENSO event (April 1999). (E) Colonies of Siderastrea stellata being attacked by echinoids grazing on the top of Guarajuba reef in April 1999. (F) The reef top of Praia do Forte in April 2011. Quadrats: 1 m2.

References [+] :

Barber, Biological consequences of el nino. 1983, Pubmed