# Magnetic Island, Great Barrier Reef, Porites spp. coral isotopes and trace elements from -4099 to 1985 CE #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # Template Version 4.0 # Encoding: UTF-8 # NOTE: Please cite original publication, NOAA Landing Page URL, dataset and publication DOIs (where available), and date accessed when using downloaded data. # If there is no publication information, please cite investigator, study title, NOAA Landing Page URL, and date accessed. # # Description/Documentation lines begin with '#' followed by a space # Data lines have no '#' # # NOAA_Landing_Page: https://www.ncei.noaa.gov/access/paleo-search/study/39060 # Landing_Page_Description: NOAA Landing Page of this file's parent study, which includes all study metadata. # # Study_Level_JSON_Metadata: https://www.ncei.noaa.gov/pub/data/metadata/published/paleo/json/noaa-coral-39060.json # Study_Level_JSON_Description: JSON metadata of this data file's parent study, which includes all study metadata. # # Data_Type: Corals and Sclerosponges # # Dataset_DOI: # # Science_Keywords: hydrology, Other Reconstruction #--------------------------------------- # Resource_Links # # Data_Download_Resource: https://www.ncei.noaa.gov/pub/data/paleo/coral/west_pacific/great_barrier/lewis2005/lewis2005-mag01d.txt # Data_Download_Description: NOAA Template File; MAG01D d13C, d18O, trace metals Data # #--------------------------------------- # Contribution_Date # Date: 2024-02-17 #--------------------------------------- # File_Last_Modified_Date # Date: 2024-02-17 #--------------------------------------- # Title # Study_Name: Magnetic Island, Great Barrier Reef, Porites spp. coral isotopes and trace elements from -4099 to 1985 CE #--------------------------------------- # Investigators # Investigators: Lewis, Stephen E. (https://orcid.org/0000-0002-6929-6626) #--------------------------------------- # Description_Notes_and_Keywords # Description: Contributed as part of the Great Barrier Reef Coral Skeletal Records Database (GBRCD). # Provided Keywords: Great Barrier Reef, Holocene, corals, terrestrial runoff, sedimentation #--------------------------------------- # Publication # Authors: Lewis, S.E. # Published_Date_or_Year: 2005 # Published_Title: Environmental Trends in GBR lagoon and Burdekin River catchment during the mid-Holocene and since European settlement using Porites coral records, Magnetic Island, QLD # Journal_Name: # Volume: # Edition: # Issue: # Pages: # Report_Number: # DOI: # Online_Resource: # Full_Citation: Lewis, S.E. (2005), ‘Environmental Trends in GBR lagoon and Burdekin River catchment during the mid-Holocene and since European settlement using Porites coral records, Magnetic Island, QLD’, PhD Thesis, James Cook University. # Abstract: The extent of human influence on the Great Barrier Reef (GBR) is controversial but is essential to understand the environmental parameters of "healthy" inshore coral reefs before European settlement and the agriculturally-modified adjacent land catchments. To provide this evidence, core samples were taken from massive Porites corals from Magnetic Island and their annual skeletal growth bands were analysed for trace elements and oxygen isotope composition at sub-annual, 2 and 5 yearly sampling resolutions. This geochemical database was exploited to develop proxies of sea surface temperature (SST), seawater salinity, terrestrial runoff, land practices, sedimentation and turbidity. Data were obtained from four long-lived (~100 years) fossil mid-Holocene corals (~6,000 years old) and three modern coral cores, including one with a growth record from 1812-1986, a record which pre-dates European settlement in the region (c. 1850). In addition, the Holocene evolution of the Nelly Bay (Magnetic Island) reef was examined from C-14 dated sediment cores and biological sea-level indicators to construct a stratigraphic model of Nelly Bay. This model helps to investigate cause of the death for the fossil corals. The mid-Holocene corals died around 5,790-6,150 calibrated (cal) years BP most probably from burial by terrigenous and biogenic sediments (sedimentation) due to a prograding reef flat. The fossil mid-Holocene corals contained sediment trapped within their final growth bands that was evident from elevated Th concentrations (>3 ppb), lower Y/Ho ratios (< 40) and progressively "flatter" rare earth element and Y (REY) distributions. REY distributions indicate that the sediments within the fossil coral's skeleton came from the local (Nelly Bay) area rather than the Burdekin River catchment. Sea level rapidly transgressed to + 1.0-1.5 m around 7,000-7,500 cal years BP and may have then oscillated up to four times before settling to its current position approximately 1,250 cal years BP. Sea-level in the region was reconstructed from C-14 ages of a fossil oyster bed from Magnetic Island and by compiling previous sea-level data from eastern Australia. Average climate variability during the mid-Holocene was similar to the 1812-1986 coral record from the coral proxies of SST (Sr/Ca, Mg/Ca, U/Ca ratios and d18O composition). The Sr/Ca ratios in the 1812-1986 coral record were significantly correlated with the instrumental dataset from the central GBR at a 2 yearly sampling resolution, while the long-term averages of the other SST proxies agreed with the instrumental record. In addition, there were significant correlations between the coral Sr/Ca ratio and the coral calcification rate (a physical coral SST proxy) at the 2 and 5 yearly sampling resolutions. Average seawater salinity (coral ?¹8O) during the mid-Holocene was also similar to the 1812-1986 coral record. The ?¹8O record for the 1812-1986 coral showed relatively wetter conditions persisted from 1885-1935 and post-1970, while drier conditions prevailed between 1830-1885 and 1935-1970. These long-term trends agreed with the coral luminescence and the rainfall records and coincide with the Pacific Decadal Oscillation. However, correlations between the coral ?¹8O record and luminescence, rainfall and Burdekin River discharge were not significant, although the coral luminescence record was significantly correlated with rainfall in the Burdekin catchment and Burdekin River discharge records. The lack of correlation between coral ?¹8O and luminescence records indicates these proxies are recording different environmental signals. The 5 yearly resolution coral ?¹8O record reveals subtle, long-term variations in seawater salinity, whereas the luminescence record shows large, short-term variations in seawater salinity from rainfall and river discharge events. The study supports the finding that sediment and colloidal export to the GBR have increased by 4-5 times in the Burdekin River catchment since the arrival of Europeans, based on coral Ba/Ca ratios, Y, Pr, Sm and Ho concentrations as well as REE distribution patterns in the 1812-1986 record. The Ba/Ca ratios and the Y, Pr, Sm and Ho concentrations were significantly correlated with cattle numbers in the Burdekin River catchment. However, previous claims that the additional sediment exported to the inshore GBR has resulted in an increase in turbidity levels are not supported by the coral Y/Ho ratio, a potential proxy of turbidity. In addition, negligible sediment has been trapped within the 1812-1986 coral skeleton, which was evident from low coral Th concentrations. This finding indicates that the threat of sedimentation to the Magnetic Island’s fringing reefs is low. An excellent record of historical land-use in the adjacent Burdekin River catchment is provided by coral Mn concentrations. Mn levels in the corals record the establishment and growth of the sheep and cattle industries and provide an exceptional historical account of the development of land since European settlement. This study has helped to establish a record of natural climate and environmental change on inshore coral reefs to provide a baseline of water quality conditions for "healthy" reef ecosystems. From this baseline, the study has been able to separate the natural variability on Magnetic Island's fringing reefs from the human influence and may assist decisions to manage land runoff to inshore reefs of the GBR. #--------------------------------------- # Funding_Agency # Funding_Agency_Name: # Grant: #--------------------------------------- # Site_Information # Site_Name: Geoffrey Bay, Magnetic Island # Location: Australia # Northernmost_Latitude: -19.15 # Southernmost_Latitude: -19.15 # Easternmost_Longitude: 146.858 # Westernmost_Longitude: 146.858 # Elevation_m: #--------------------------------------- # Data_Collection # Collection_Name: MAG01D d13C,d18O,trace metals Lewis2005 # First_Year: 1810 # Last_Year: 1985 # Time_Unit: year Common Era # Core_Length_m: # Parameter_Keywords: carbon isotopes, oxygen isotopes, trace metals # Notes: Porites sp. #--------------------------------------- # Chronology_Information # Chronology: #--------------------------------------- # Variables # PaST_Thesaurus_Download_Resource: https://www.ncei.noaa.gov/access/paleo-search/skos/past-thesaurus.rdf # PaST_Thesaurus_Download_Description: Paleoenvironmental Standard Terms (PaST) Thesaurus terms, definitions, and relationships in SKOS format. # # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab-var components: what, material, error, units, seasonality, data type, detail, method, C or N for Character or Numeric data) # ## age_CE age,Porites sp.,,year Common Era,,corals and sclerosponges,,,N,Age is the middle year of the 5-year resolution sampling period. ## d13C delta 13C,Porites sp.,,per mil PDB,,corals and sclerosponges,,mass spectrometry,N,Micromass PRISM III stable-isotope mass spectrometer ## d18O delta 18O,Porites sp.,,per mil PDB,,corals and sclerosponges,,mass spectrometry,N,Micromass PRISM III stable-isotope mass spectrometer ## MgCa magnesium/calcium,Porites sp.,,millimole per mole,,corals and sclerosponges,,inductively-coupled plasma atomic emission spectroscopy,N,Varian Vista ICP-AES ## Mn manganese,Porites sp.,,parts per million,,corals and sclerosponges,,inductively-coupled plasma atomic emission spectroscopy,N,Varian Vista ICP-AES ## SrCa strontium/calcium,Porites sp.,,millimole per mole,,corals and sclerosponges,,inductively-coupled plasma atomic emission spectroscopy,N,Varian Vista ICP-AES ## d18Osw delta 18O,sea water; Porites sp.,,per mil,,corals and sclerosponges,,mass spectrometry,N,Seawater d18O reconstruction. Micromass PRISM III stable-isotope mass spectrometer #------------------------ # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing_Values: NA age_CE d13C d18O MgCa Mn SrCa d18Osw 1813 -1.5 -4.4 3.47669667 0.246432 9.11912789 -0.4303 1818 -0.6 -4.4 3.486158954 0.303011 9.10632104 -0.3942 1823 -1.1 -4.5 3.6771636 0 9.05023865 -0.3365 1828 -1.3 -4.7 3.747311029 0.159138 8.99166771 -0.3724 1833 -1.2 -4.5 3.822554262 0.052213 8.95452533 -0.0665 1838 -1.2 -4.4 3.722284843 0 8.9716833 -0.0144 1843 -1 -4.3 3.717176715 0 8.9638858 0.1082 1848 -0.7 -4.3 3.492770645 0.0112 9.03162017 -0.0829 1853 -0.6 -4 3.548510982 5.449198 9.03234977 0.2167 1858 -1.2 -4.4 3.655120737 6.644752 8.98237498 -0.0445 1863 -1.7 -4.6 3.737027325 3.155529 8.88639817 0.0251 1868 -1.8 -4.2 3.856406231 4.346268 8.94075482 0.274 1873 -1.5 -4.3 3.83419043 4.269746 8.96354164 0.1092 1878 -1.4 -4.2 3.673590936 1.591676 8.92314832 0.3237 1883 -1.6 -4.2 3.685763857 3.176578 8.97447909 0.1789 1888 -1.3 -4.6 3.634498662 2.950978 9.00691385 -0.3149 1893 -1.6 -4.7 3.613283954 2.074658 8.99783684 -0.3898 1898 -1.6 -4.7 3.627448353 0.78367 9.03850885 -0.5046 1903 -1.2 -4.5 3.653224769 1.187463 8.97440799 -0.1226 1908 -2.1 -4.8 3.783364729 0.177883 8.967088 -0.4036 1913 -1.9 -4.7 3.790702121 0 8.99704836 -0.3876 1918 -1.1 -4.5 3.663957869 0.284733 9.00454328 -0.2076 1923 -1.3 -4.7 3.793412183 0.108916 8.96186947 -0.2883 1928 -1.2 -4.8 3.683192663 0.393715 8.96488069 -0.3974 1933 -1.2 -4.6 3.736913031 0.819046 8.98738628 -0.2598 1938 -1.4 -4.4 3.723765293 0.370677 8.94106113 0.072 1943 -1.3 -4.1 3.411061171 0.180534 9.04440156 0.0822 1948 -1.2 -4.4 3.702035704 1.152811 8.94076989 0.0729 1953 -1.1 -4.5 3.6444274 0.750124 8.94004811 -0.0257 1958 -1.3 -4.3 3.536240021 0.502211 9.02857041 -0.0743 1963 -0.9 -4.2 3.712963529 0.100529 8.97602783 0.1745 1968 -1.1 -4.5 3.728251698 0.379561 8.96064794 -0.0838 1973 -1.6 -4.7 3.722956189 0.3924 8.93759342 -0.4687 1978 -1.4 -4.9 3.615783596 0 8.96811228 -0.5194 1983 -1.5 -4.6 3.654427968 0 8.99577699 -0.194