Processed analyte measurements from the Great Barrier Reef's Marine Monitoring Program.

These data accompany a manuscript that examines data from the Great Barrier Reef MMP inshore \nwater quality program (MMP WQ) and assesses the impact that the sampling re-design \nhad on the power to detect trends in six priority water quality analytes, which is a primary objective \nof the MMP WQ. \n\nThe manuscript details are\n\nLuke R. Lloyd-Jones, Petra M. Kuhnert, Emma Lawrence, Stephen E. Lewis, Jane \nWaterhouse, Renee K. Gruber and Frederieke J. Kroon. Sampling re-design increases \npower to detect change in the Great Barrier Reef’s inshore water quality. 2022.\n\nThe dataset in file GBR-MMPDataset-processed-power.csv file contains data from the \nMMP WQ monitoring program.\n\nThe current MMP WQ monitors the inshore waters of the GBR Marine Park across \nfive of the six Natural Resource Management (NRM) regions: Cape York, Wet Tropics, \nBurdekin, Mackay-Whitsunday, and Fitzroy. In our study, we \nconsider monitoring data collected across four study areas within three of these \nNRM regions, namely the Russell-Mulgrave and Tully study areas (within the Wet \nTropics NRM region), the Burdekin study area (i.e., the Burdekin NRM region), \nand the Mackay-Whitsunday study area (i.e., the Mackay-Whitsunday NRM region). \n\nThe data uses inshore water quality data obtained from ambient monitoring using \ngrab samples at fixed locations across these four study areas from 2005 to 2019.\nThe data used are combined from across two research organisations that monitor\ndifferent spatiotemporal components of the GBR. The institutions include the\nAustralian Institute of Marine Science (AIMS) and James Cook University (JCU).\n\nThe MMP WQ conducts ambient water quality monitoring, including grab sampling \nduring non-event periods (i.e., outside river flooding events), to collect a suite \nof physical, chemical, and biological water quality analytes at each sampling \nlocation. \n\nThese data are for six water quality analytes, namely total suspended \nsolids (TSS), Secchi disc depth (Secchi), Chlorophyll a (Chl-a), particulate \nnitrogen (PN), particulate phosphorus (PP), and nitrate/nitrite (NOx). These \nsix analytes are considered relatively robust indicators that integrate several \nbio-physical processes in the coastal ocean, and water quality guideline values \nare available for all six of these analytes.\nLineage: The data presented in GBR-MMPDataset-processed-power.csv have been preprocessed\nfrom the raw data. The raw data were received from AIMS and processed for the \npower analysis as below.\n\nFor each sampling time point at each sampling location, values for each water \nquality analyte were initially averaged over any duplicate measurements, and \nsubsequently depth-averaged by taking the mean of surface and bottom values, \nwhich is the standard for the MMP WQ reporting. Measurements of nitrite and \nnitrate in the tropical coastal ocean are often below the detection limit (BDL) of \nanalytical instruments, which are reported as half the detection limit (1/2DL) in \nthe MMP WQ dataset. NOx measurements can therefore represent (1) the sum of two \nBDL measurements, or (2) comprise a BDL measurement and a concentration \nmeasurement above the detection limit. For NOx, we investigated the implications \nof imputing BDL values with 1/2DL values on statistical power by comparing \nresults with two other methods (see manuscript for more details).