Algal Turf Sediments and Sediment Production by Parrotfishes across the Continental Shelf of the Northern Great Barrier Reef

摘要: Sediments are found in the epilithic algal matrix (EAM) of all coral reefs and play important roles ecological processes. Although we have some understanding patterns EAM sediments across individual reefs, our knowledge broader spatial scales is limited. We used an underwater vacuum sampler to quantify two most ecologically relevant factors Great Barrier Reef: total load grain size distribution. compare these with rates sediment production reworking by parrotfishes gain insights into potential contribution sediments. Inner-shelf reef EAMs had highest loads a mean 864.1 g m-2, compared 126.8 m-2 287.4 on mid- outer-shelf respectively. High were expected inner-shelf due their proximity mainland, however, terrigenous siliceous only accounted for 13–24% mass. On crests would take three months produce equivalent mass EAM. it just days, suggesting that characterised low turnover. By contrast, on-reef high crests. However, exposure oceanic swells means much this likely be lost. Hydrodynamic activity also appears structure at within-reef scales, coarser (> 250 μm) typifying exposed crest EAMs, finer (< sheltered back-reef EAMs. As both mediate number processes observed gradients key role function associated communities.