Perspectives on the Great Amazon Reef: Extension, Biodiversity, and Threats

Abstract

Here we provide a broad overview of the Great Amazon Reef System (GARS) based on the first-ever video surveys of the region. This footage supports four major hypotheses: (1) the GARS area may be six times larger than previously suggested (up to 56,000 km 2 ); (2) the GARS may extend deeper than previously suggested (up to 220 m); (3) the GARS is composed of a greater complexity and diversity of habitats than previously recognized (e.g., reef platforms, reef walls, rhodolith beds, and sponge bottoms); and (4) the GARS represents a useful system to test whether a deep corridor connects the Caribbean Sea to the Southwest Atlantic Ocean. We also call attention to the urgent need to adopt precautionary conservation measures to protect the region in the face of increasing threats from extractive oil and gas practices. With less than 5% of the potential area of the GARS surveyed so far, more research will be required to inform a systematic conservation planning approach and determine how best to establish a network of marine protected areas. Such planning will be required to reconcile extractive activities with effective biodiversity conservation in the GARS.

Mesophotic ecosystems: Distribution, impacts and conservation in the South Atlantic

“…Francini‐Filho et al. () suggested that these MEs comprise a significant diversity of environments, including rhodolith beds, sponge grounds and reef structures, such as biogenic walls and platforms.…”

“…These Amazonian MEs (the Great Amazon Reef sensu Francini‐Filho et al., ) are distributed across a large area (56,000 km²) of the North Brazil Shelf, between the shelf‐edge and the upper slope (70–220 m depth; Francini‐Filho et al., ). Despite the variability of seascapes, this ecosystem has a clear bathymetric gradient: Rhodolith beds and algal frameworks dominate the shallowest sector (70–180 m), but in the deepest sector (180–220 m), marine animal forests (composed of black corals, barrel sponges and octocorals) and associated fishes (e.g., butterflyfish) are more common.…”

“…Red algae were the predominant benthic plant group, with 25 species. The sponge assemblage comprised 61 species and was dominated by massive forms (Francini‐Filho et al., ; Moura et al., ). Two black coral species, Antipathes furcata and Tanacetipathes tanacetum , typical of mesophotic reefs, were detected in the deeper zones.…”

Geomorphometric Seabed Classification and Potential Megahabitat Distribution in the Amazon Continental Margin

“…These geologically similar margins comprise large accumulations of oil with high commercial value (Milani et al, 2001). More than a hundred exploratory blocks have been auctioned by Brazil since 2012, but environmental licensing is still a matter of discussion and concern (e.g., Francini-Filho et al, 2018), largely due to the recently mapped reef system off the Amazon mouth (Cordeiro et al, 2015;Moura et al, 2016).…”

“…Considering the expansion of the oil and gas industry in the ACM, the occurrence of mesophotic reefs along the shelf and shelf break (Moura et al, 2016), and even the overestimated size of the "Great Amazon reefs" by Francini-Filho et al (2018), a quantitative terrain characterization is a powerful tool to map potential benthic habitats based on their morphology (Lecours et al, 2016) and to set the stage for marine spatial planning (e.g., Moura et al, 2013). Herein, a quantitative terrain characterization is used to map potential benthic habitats based on their morphology.…”