This dataset consists of one spreadsheet, which shows the survival, number of polyps and ability to remove sediment of up to fourteen weeks old Acropora millepora coral recruits while being exposed to three different climate scenarios resembling current climate conditions and conditions expected by mid and end of the century. Coral recruit resilience towards sedimentation was tested by exposing the recruits either five- and ten-weeks following settlement (experiment 1) or only ten-weeks following settlement (experiment 2). Additional tabs show temperature, pCO2 and sediment loads used in the experiment. The study was conducted at the National Sea Simulator. The aim of this study was to 1) identify lethal concentration thresholds for coral recruits under simultaneous exposure to climate stress (temperature and pCO2) and sedimentation and 2) identify survival mechanisms (i.e., number of polyps, sediment removal capability). This data will inform the development of water-quality management guidelines, a key aim of NESP project 5.2. The full research report can be found at: Brunner CA, Uthicke S, Ricardo GF, Hoogenboom MO, Negri AP (2020) Climate change doubles sedimentation-induced coral recruit mortality. Science of the Total Environment, doi.org/10.1016/j.scitotenv.2020.143897 Methods: Coral recruits of Acropora millepora, a branching coral species abundant in shallow reefs on the Great Barrier Reef, were raised for 14 weeks in ‘current’ and realistic ‘medium’ and ‘high’ climate scenarios (increased temperature and acidification), and were exposed to six environmentally relevant sediment deposition loads typical of flood plumes and dredging operations. The sedimentation events were simulated at different recruit ages: (1) five- and ten-weeks following settlement, and (2) after ten weeks only. One-hour following sediment exposures, sediment removal capabilities were photographically quantified. After a four-week recovery phase, survival and polyp numbers were documented photographically and the data are presented here. Specific details of the methodology may be found in: Brunner CA, Uthicke S, Ricardo GF, Hoogenboom MO, Negri AP (2020) Climate change doubles sedimentation-induced coral recruit mortality. Science of the Total Environment, doi.org/10.1016/j.scitotenv.2020.143897 Format: This dataset consists of one excel workbook xlsx. Data Dictionary: Experiment tab DATE SETTLEMENT - Date of coral larvae settlement, t0 DATE MEASUREMENT - Date survival and polyp numbers were documented AGE - age in weeks following settlement EXPERIMENT - (1): Coral recruits were exposed for three days to sedimentation when 5 and 10 weeks old; (2): Coral recruits were exposed for three days to sedimentation when 10 weeks old, see also "date sediment exposure" CLIMATE SCENARIO - climate scenarios based on manipulated temperature and pCO2, see "Temperatures" and "pCO2" tab for details ID TANK - identification number of climate controllable aquarium ID DISC TRAY - identification number of tray where the discs were mounted ID DISC - identification number of discs where coral recruits settled on ID RECRUIT PER DISC - identification number of each recruit on each disc SEDIMENT (mg / cm²) - sediment load NUMBER OF POLYPS - number of alive polyps CORAL ALIVE - (1): coral is alive, (0): coral is dead DATE SEDIMENT EXPOSURE - timeframe of sedimentation, NA shows that no sediment was applied in this period SEDIMENT FREE AFTER 1 HOUR - (1): coral was sediment free 1h after sediment was applied, (0): coral was not sediment free Temperature tab DATE - date of temperature measurement TIME - time of temperature measurement CORAL AGE (WEEKS AFTER SETTLEMENT) - age in weeks following settlement CURRENT TEMPERATURE (°C) - 26.2 – 28.7 MEDIUM TEMPERATURE (°C) - Current + 0.6 HIGH TEMPERATURE (°C) - Current + 1.2 pCO2 tab DATE - date of pCO2 measurement TIME - time of pCO2 measurement CORAL AGE (WEEKS AFTER SETTLEMENT) - age in weeks following settlement CURRENT pCO2 (ppm) - 410 ± 50 MEDIUM pCO2 (ppm) - 680 ± 50 HIGH pCO2 (ppm) - 940 ± 50 Sediment tab CLIMATE SCENARIO - climate scenarios based on manipulated temperature and pCO2, see "Temperatures" and "pCO2" tab for details ID TANK - identification number of climate controllable aquarium ID DISC TRAY - identification number of tray where the discs were mounted ID DISC -identification number of discs where coral recruits settled on FILTER PREMASS (g) - Weight of 0.4 µm polycarbonate filters FILTER WITH SEDIMENT (g) - weight of dried (60 °C for greater than or equal to 24 hours) 0.4 µm polycarbonate filters with sediment SEDIMENT ON FILTER (g) - weight of filter with sediment - filter premass DISC SURFACE (cm²) - disc surface area based on 2 cm diameter SEDIMENT INITIALLY APPLIED (mg / cm²) - sediment load at the beginning of the sediment deposition experiment SEDIMENT REMAINING AFTER THREE DAYS (mg/cm²) - sediment load at the end of the sediment deposition experiment References: Brunner CA, Uthicke S, Ricardo GF, Hoogenboom MO, Negri AP (2020) Climate change doubles sedimentation-induced coral recruit mortality. Science of the Total Environment, doi.org/10.1016/j.scitotenv.2020.143897 Data Location: This dataset is filed in the eAtlas enduring data repository at: data\nesp5\5.2_Cumulative-impacts

This dataset contains data from experiments testing the survival of fertilised Acropora millepora gametes before and after settlement in different climate and sediment treatment conditions. One datafile shows the development and survival until competency for settlement, which has been tested at the National Sea Simulator. A second file demonstrates the settlement success after development in these treatments. Successful recruitment is crucial for the survival and repopulation of coral reefs. Studies have shown that the different phases from gamete release, fertilisation and larvae development may be affected by suspended sediments, increasing temperatures or ocean acidification. To date, the cumulative impact of all three stressors has not been evaluated. Note that the gametes were exposed to the climate and sediment treatments after fertilisation. Methods: The cumulative effect of suspended sediment and climate stress on the larvae development of Acropora millepora was tested in this experiment. A. millepora colonies containing eggs were collected in the reefs surrounding Falcon Island, GBR (Permit: G12/35236.1, Location: S18°46'15", E146°31'57") about one week prior to the annual spawning event in late November / December 2017. Gametes were collected, and fertilisation initiated on 14.12.2017. After 45 minutes, the fertilised eggs were rinsed with filtered seawater and transferred (n = 60) into twelve 500 mL Schott glass bottles. Sediment was added (Middle Reef, ~ 10µm) (Table 1), the bottles sealed, and they were then placed onto half-submerged roller tables in three different treatments resembling current (10-year historic daily mean reef temperature at Davies Reef, ~27°C) and predicted mid and end century climate conditions. Climate conditions: Today: +0°C Temp, 440 ± 50 PCo2 [ppm], sediment [mg/ml-1] 0, 10, 30, 100 Mid Century: +1°C Temp, 660 ± 50 PCo2 [ppm], sediment [mg/ml-1] 0, 10, 30, 100 End Century: +2°C Temp, 940 ± 50 PCo2 [ppm], sediment [mg/ml-1] 0, 10, 30, 100 To achieve a constant pCO2 within each bottle, they were kept closed, while the water-baths regulated their temperature. Since stagnant water may cause lethal larval aggregation at the water surface, the bottles were in continuous motion on half-submerged roller tables. The coral larvae development and mortality in the bottles was documented every day for a seven-day period. At the end of each day, the water was exchanged to provide consistent water quality across all treatments during the entire experiment. At the same time point the sediment was replaced with fresh material, since it aggregated and deposited on the bottom of the bottles within approximately 12 hours (e.g. for 100 mg ml-1 t0: 100 mg ml-1, t12: ~0 mg ml-1). The aggregation to sticky flocs was likely caused by mucus production of the larvae and introduced organic matter due to mortality (Fabricius and Wolanski 2000; Ricardo et al. 2016b). By exchanging the material, a daily sediment resuspension event was simulated. Coral larvae require cues to induce their settlement and subsequent metamorphosis to a coral polyp (Harrington et al. 2004). To identify how many days after fertilisation the highest settlement competency is achieved, settlement assays using CCA chips (Hydrolithon onkodes, size: 4 x 4 mm) and A. millepora larvae from ambient condition were performed, starting three days after fertilisation. After seven days, no increase in settlement success (90%) was detected. Therefore, the larvae developed under different sediment and climate scenarios were exposed to CCA chips after seven days and their settlement success documented 24 h later. Format: Brunner_Larvae_count.csv It provides age, sediment concentration, climate treatment and the total count (initially n = 60) of alive larvae. Brunner_CCA_Settlement.csv The file provides count data of settled recruits (out of 10 exposed larvae) originating from different sediment and climate treatments. Data Dictionary: Brunner_Larvae_count.csv DATE: The date larvae survival was documented and the water together with the old sediment was changed. AGE: Days after fertilisation. BOTTLE_NO: Bottle number in the respective climate. CLIMATE: Climate treatment (Temperature and acidification as described in the methods). SED_CONC: New sediment (mg L-1) added to the bottles on each 'Date'. COUNT: Total number of living larvae (max 60) at the point in time specified by 'Date'. Brunner_CCA_Settlement.csv DATE_SET: Date larvae were exposed to CCA chips (Hydrolithon onkodes) for settlement. DATE_COUNT: Date settled larvae were counted. CLIMATE: Climate treatment (Temperature and acidification as described in the methods). SED_CONC: Sediment concentration (mg L-1) the larvae were exposed to during their development. SET: Number of larvae that successfully settled on the bottom or CCA chip. TOTAL: Total number of recruits that were found during the counts (Initially n = 10). Data Location: This dataset is filed in the eAtlas enduring data repository at: data\custodian\2016-18-NESP-TWQ-2\2.1.6_Cumulative-impacts\data\larvae-development