An assessment of an environmental gradient using coral geochemical records, Whitsunday Islands, Great Barrier Reef, Australia

• Published in: Marine pollution bulletin Vol. 65; no. 4-9; pp. 306 - 319
• Main Authors: Lewis, S.E., Brodie, J.E., McCulloch, M.T., Mallela, J., Jupiter, S.D., Stuart Williams, H., Lough, J.M., Matson, E.G.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-01-2012
• Subjects: Animals; Anthozoa - chemistry; Australia; Ba/Ca; barium; calcium; Coral Reefs; corals; environmental assessment; Environmental Monitoring - methods; Freshwater; Great Barrier Reef; infrastructure; islands; land use; manganese; Marine; Mn/Ca; nitrogen; rivers; Rivers - chemistry; stable isotopes; tourism; trace elements; Trace Elements - analysis; Water Movements; Water Pollutants, Chemical - analysis; water pollution; Water Pollution, Chemical - statistics & numerical data; water quality; Water quality gradient; watersheds; Y/Ca; δ15N; Australia; ISEW, Australia, Queensland, Great Barrier Reef; ISEW, Australia, Queensland, Great Barrier Reef, Whitsunday Is; ISEW, Australia, Queensland, The Whitsundays; Ba/Ca; δ15N; Mn/Ca; Y/Ca; Water quality gradient; Great Barrier Reef
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2011.09.030

► First study to use coral proxy records to examine the Whitsunday Islands gradient. ► First study to show a regional GBR-scale change in the coral Ba/Ca ratio after 1860. ► Research provides new insights into the environmental influences on coral proxies. ► Research shows a change in the environmental gradient since European settlement.
Coral cores were collected along an environmental and water quality gradient through the Whitsunday Island group, Great Barrier Reef (Australia), for trace element and stable isotope analysis. The primary aim of the study was to examine if this gradient could be detected in coral records and, if so, whether the gradient has changed over time with changing land use in the adjacent river catchments. Y/Ca was the trace element ratio which varied spatially across the gradient, with concentrations progressively decreasing away from the river mouths. The Ba/Ca and Y/Ca ratios were the only indicators of change in the gradient through time, increasing shortly after European settlement. The Mn/Ca ratio responded to local disturbance related to the construction of tourism infrastructure. Nitrogen isotope ratios showed no apparent trend over time. This study highlights the importance of site selection when using coral records to record regional environmental signals.