The frequency of coral bleaching events recorded on the Great Barrier Reef has increased. Coral bleaching is caused by a variety of factors, including thermal stress and high irradiance and a reduction of these stressors may reduce incidence of coral bleaching. "Sun Shield" is a thin film predominantly composed of calcium carbonate, which can be applied on the water's surface to act as a shade and reduce irradiance stress to corals. Formulations were preliminary tested at the University of Melbourne, Victoria. Tank and open ocean trials were performed at the Australian Institute of Marine Science and its surrounds in Townsville, Queensland. Sun Shield reduced irradiance by 20% in open ocean trials and has the potential to reduce coral bleaching severity at small scale.

Oceanographic loggers have been deployed continuously at our EcoRRAP monitoring sites since inception in 2021. Deployments are typically for 12 months, with loggers exchanged and data retrieved during the annual monitoring expeditions. Data have been collected to provide explanatory information for ecological datasets, and for model parameterisation. At the main reef per cluster (i.e. Masig Island, Lizard Island, Moore Reef, Pelorus Island, Davies Reef, Mial Island and Heron Island) an array of loggers was deployed at one of the Front Deep zones. These loggers measured salinity, temperature, depth, light (PAR) and currents (current profiles and surface waves). The loggers were attached to a 1m2 flat steel frame affixed to the seafloor so that the instrument sensors were approximately 50cm from the bottom. A Spotter wave buoy was also deployed adjacent to each main-reef instrument array. These measured surface wave and temperature (at 5m deep and the seafloor) data, as well as calculated wind speeds. Some later Spotter models also measured barometric pressure. The Spotter temperature data timeseries are typically shorter than the wave timeseries. Temperature sensors and tilt current meters were further deployed at many other zones. Exact deployment details are described in the “202411_EcoRRAP_logger_metadata_record.xls” spreadsheet attached. Temperature loggers were generally deployed at one zone type per reef. Where a zone type is a combination of reef aspect and depth. For example, Front1 shallow and Front1 deep are different zone types, while Front1 shallow and Front2 shallow are the same zone type (i.e. both Front sites at the same depth). Smaller reefs and reefs with presumably more homogenous temperatures had lower numbers of site types monitored for temperature due to limited numbers of sensors available. Tilt current meters were deployed at each zone at different time points throughout the sampling period. These deployments were typically for 2 – 3 months. Instruments used: The below is a list of logger types used for the different parameters. Refer to the manufacturer’s websites for further product information and user guides. Loggers were typically deployed with 10 minute sampling intervals. Wave measurements were conducted every two or three hours depending on instrument model to maximise deployment length. CTDs (conductivity / salinity, temperature and depth): Seabird Electronics SBE37: https://www.seabird.com/moored/sbe-37-sm-smp-smp-odo-microcat/family?productCategoryId=54627473786 Seabird Electronics SBE16 Plus: https://www.seabird.com/sbe-16plus-v2-seacat/product?id=60761421598 Light (PAR): Licor light sensor (LI-192) attached to RBR solo3 logger: https://rbr-global.com/products/compact-loggers/rbrsolo-do-tu-par/ RBR solo PAR: https://rbr-global.com/products/compact-loggers/rbrsolo-par-rad/ Light bio-wiper: zebratech - https://www.zebra-tech.co.nz/hydro-wiper/ Depth: RBR solo3 D - https://rbr-global.com/products/compact-loggers/rbrsolo-d/ Temperature: RBR solo3 T - https://rbr-global.com/products/compact-loggers/rbrsolo-t-2/ Seabird Electronics SBE39: https://www.seabird.com/moored/sbe-39plus-temperature-depth-recorder/family?productCategoryId=54627473774 Acoustic currents and waves: Nortek Signature1000: https://www.nortekgroup.com/products/signature-1000 Nortek AWAC 600kHz: https://www.nortekgroup.com/products/awac-600-khz Nortek Aquadopp profiler: https://observator.com/products/nortek-aquadopp-profiler/ Teledyne RDI ADCP: https://www.teledynemarine.com/en-us/products/Pages/workhorse-sentinel-adcp.aspx Tilt current meter: Marotte: https://www.marinegeophysics.com.au/current-meter/ Wave buoy and temperature string: Sofar Ocean Spotter smart mooring: https://www.sofarocean.com/posts/introducing-spotter-smart-mooring The file structure of processed data are organised by parameter and then collection fieldtrip (date and then AIMS fieldtrip numbers). Typically a collection fieldtrip visited one or two of our EcoRRAP regions in the Torres strait, Northern, Central and Southern Great Barrier Reef. So as an example, temperature data from PAOR_FL1S between 23/1/21 – 30/3/21, retrieved on fieldtrip 7626 (the first data row in the attached deployment metadata spreadsheet), can be found in the folder “CTD_DATA \ 202103_7626_Central_GBR” being a combination of parameter (CTD), collection fieldtrip date (March 2021), AIMS fieldtrip number (7626) and region (Central GBR).