title: Evidence of extensive reef development and high coral cover in nearshore environments: implications for understanding coral adaptation in turbid settings.
abstract: Mean coral cover has reportedly declined by over 15% during the last 30 years across the central Great Barrier Reef (GBR). Here, we present new data that documents widespread reef development within the more poorly studied turbid nearshore areas (<10 m depth), and show that coral cover on these reefs averages 38% (twice that reported on mid- and outer-shelf reefs). Of the surveyed seafloor area, 11% had distinct reef or coral community cover. Although the survey area represents a small subset of the nearshore zone (15.5 km(2)), this reef density is comparable to that measured across the wider GBR shelf (9%). We also show that cross-shelf coral cover declines with distance from the coast (R(2) = 0.596). Identified coral taxa (21 genera) exhibited clear depth-stratification, corresponding closely to light attenuation and seafloor topography, with reefal development restricted to submarine antecedent bedforms. Data from this first assessment of nearshore reef occurrence and ecology measured across meaningful spatial scales suggests that these coral communities may exhibit an unexpected capacity to tolerate documented declines in water quality. Indeed, these shallow-water nearshore reefs may share many characteristics with their deep-water (>30 m) mesophotic equivalents and may have similar potential as refugia from large-scale disturbances.
authors.affiliation: Department of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
authors.forename: Kyle M
authors.initials: KM
authors.lastname: Morgan
authors.affiliation: Department of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
authors.forename: Chris T
authors.initials: CT
authors.lastname: Perry
authors.affiliation: College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia.
authors.forename: Scott G
authors.initials: SG
authors.lastname: Smithers
authors.affiliation: Department of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
authors.forename: Jamie A
authors.initials: JA
authors.lastname: Johnson
authors.affiliation: College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia.
authors.forename: James J
authors.initials: JJ
authors.lastname: Daniell
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D037421:Anthozoa / Q000145:classification / Q000254:growth & development* / Q000502:physiology; D002170:Canada; D003247:Conservation of Natural Resources; D057894:Coral Reefs; D017753:Ecosystem; D004784:Environmental Monitoring; D060753:Water Quality