Cross shelf benthic biodiversity patterns in the Southern Red Sea

Abstract

The diversity of coral reef and soft sediment ecosystems in the Red Sea has to date received limited scientific attention. This study investigates changes in the community composition of both reef and macrobenthic communities along a cross shelf gradient. Coral reef assemblages differed significantly in species composition and structure with location and depth. Inner shelf reefs harbored less abundant and less diverse coral assemblages with higher percentage macroalgae cover. Nutrient availability and distance from the shoreline were significantly related to changes in coral composition and structure. This study also observed a clear inshore offshore pattern for soft sediment communities. In contrast to the coral reef patterns the highest diversity and abundance of soft sediment communities were recorded at the inshore sites, which were characterized by a higher number of opportunistic polychaete species and bivalves indicative of mild disturbance. Sediment grain size and nutrient enrichment were important variables explaining the variability. This study aims to contribute to our understanding of ecosystem processes and biodiversity in the Red Sea region in an area that also has the potential to provide insight into pressing topics, such as the capacity of reef systems and benthic macrofaunal organisms to adapt to global climate change.

Seasonal variation ofSargassum ilicifolium(Phaeophyceae) growth on equatorial coral reefs

“…For example, water quality (e.g., nutrient and sedimentation rates) has been shown to vary from inshore to offshore and influence benthic community structure (Ellis et al. ). Within Singapore, environmental gradients have been linked to inshore reefs having less abundant and diverse coral communities and higher macroalgal cover, compared to reefs further offshore (Dikou and van Woesik ).…”

“…Interestingly, mean daily water temperature did not differ among our study sites, suggesting other factors may regulate S. ilicifolium density and growth patterns on reefs in Singapore. For example, water quality (e.g., nutrient and sedimentation rates) has been shown to vary from inshore to offshore and influence benthic community structure (Ellis et al 2017). Within Singapore, environmental gradients have been linked to inshore reefs having less abundant and diverse coral communities and higher macroalgal cover, compared to reefs further offshore (Dikou and van Woesik 2006).…”

Disentangling the complex microbial community of coral reefs using standardized Autonomous Reef Monitoring Structures (ARMS)

“…Benthic reef community surveys (20 m × 1 m transects at 8–10 m depth) were conducted at the time of ARMS deployment. In total, triplicate transects (separated by 5 m) were undertaken at each reef with photographs taken every 2 m as described by Ellis et al (). Identification of the benthic groups (hard coral, soft coral, turf algae, macro algae and abiotic) along each transect utilized the software coral point count with excel extensions for 48 randomly distributed points over a 1‐m 2 frame.…”

Cross-shelf Heterogeneity of Coral Assemblages in Northwest Australia

“…The cumulative effects of these stressors give rise to spatially and temporally variable inshore benthic communities, usually with low cover and diversity of scleractinian corals, with assemblages dominated by robust, heat, predator, and sediment-resistant taxa, such as Pavona, encrusting Porites and Turbinaria spp. [27][28][29][30][31][32][33]. Conversely, offshore sites tend to have higher coral cover, greater diversity and are characterised by taxa that are more sensitive to heat stress, light limitation and sedimentation such as Acropora and Pocillopora [6,10,34].…”