Abrolhos Bank Reef Health Evaluated by Means of Water Quality, Microbial Diversity, Benthic Cover, and Fish Biomass Data

Abstract

The health of the coral reefs of the Abrolhos Bank (southwestern Atlantic) was characterized with a holistic approach using measurements of four ecosystem components: (i) inorganic and organic nutrient concentrations, [1] fish biomass, [1] macroalgal and coral cover and (iv) microbial community composition and abundance. The possible benefits of protection from fishing were particularly evaluated by comparing sites with varying levels of protection. Two reefs within the well-enforced no-take area of the National Marine Park of Abrolhos (Parcel dos Abrolhos and California) were compared with two unprotected coastal reefs (Sebastião Gomes and Pedra de Leste) and one legally protected but poorly enforced coastal reef (the “paper park” of Timbebas Reef). The fish biomass was lower and the fleshy macroalgal cover was higher in the unprotected reefs compared with the protected areas. The unprotected and protected reefs had similar seawater chemistry. Lower vibrio CFU counts were observed in the fully protected area of California Reef. Metagenome analysis showed that the unprotected reefs had a higher abundance of archaeal and viral sequences and more bacterial pathogens, while the protected reefs had a higher abundance of genes related to photosynthesis. Similar to other reef systems in the world, there was evidence that reductions in the biomass of herbivorous fishes and the consequent increase in macroalgal cover in the Abrolhos Bank may be affecting microbial diversity and abundance. Through the integration of different types of ecological data, the present study showed that protection from fishing may lead to greater reef health. The data presented herein suggest that protected coral reefs have higher microbial diversity, with the most degraded reef (Sebastião Gomes) showing a marked reduction in microbial species richness. It is concluded that ecological conditions in unprotected reefs may promote the growth and rapid evolution of opportunistic microbial pathogens.

Variability in Microbial Community Composition and Function Between Different Niches Within a Coral Reef

“…Our results demonstrate that at a finer scale, the distribution and diversity of Archaea is not uniform across Heron Island Reef. Archaea only comprised a maximum of 1.2 % of all sequences, but this is comparable to the relative abundance of archaeal sequences found in other coral reef environments [33].…”

“…This study also reported a shift in metabolism from autotrophy in healthy corals to heterotrophy in bleached corals and a higher proportion of virulence factors in the microbial community associated with bleached corals. Furthermore, metagenomics has shown clear shifts in taxonomic composition and metabolic potential between four coral atolls in the Northern Line Islands (central Pacific Ocean) [18] and the Abrolhos Bank coral reefs off the coast of Brazil (south-western Atlantic Ocean) [33].…”

“…The coral reef metagenomic studies performed to date have collectively enhanced our understanding of coral reef microbiology by describing patterns in microbial structure and function in specific coral species [30][31][32][33], across different coral reef ecosystems [18,33] and under changing environmental conditions and stress levels [31,32]. However, we still have little insight into how the composition and function of microbial assemblages varies within a single reef ecosystem.…”

Are Abrolhos no-take area sites of naïve fish? An evaluation using flight initiation distance of labrids

“…deep reefs, rhodolith beds and mangroves). A reduction in the biomass of herbivorous species and increased cover of macroalgae, which are the main competitors of reef-building corals and therefore a threat for reef construction (McCook et al, 2001;Padovani-Ferreira et al, 2012) in the Abrolhos Bank, highlighted the poor enforcement of Brazilian marine NTAs (Bruce et al, 2012).…”

Community structure of shallow rocky shore fish in a tropical bay of the southwestern Atlantic

“…Besides their ecological relevance, reef systems are also economically important for thousands of people living in tropical coastal areas (RUSS, 1991;COSTANZA et al, 1997;MOBERG;FOLKE, 1999;RUSS;ALCALA, 1999). However, all these environments are in a critical state of degradation, mainly due to natural and anthropogenic factors such as global climate change, marine pollution, overfishing and unplanned coastal development (HUGHES, 1994;DUFFY, 2003;PANDOLFI et al, 2003;BELLWOOD et al, 2004;WILKINSON, 2008;BRUCE et al, 2012;.…”