Abstract:
The effect of European settlement on water quality in the Great
Barrier Reef of Australia is a long-standing and controversial
issue. Erosion and sediment transport in river catchments in this
region have increased substantially since European settlement, but the
magnitude of these changes remains uncertain. Here we report analyses
of Ba/Ca ratios in long-lived Porites coral from Havannah Reef - a
... site on the inner Great Barrier Reef that is influenced by flood
plumes from the Burdekin river - to establish a record of sediment
fluxes from about 1750 to 1998. We find that, in the early part of the
record, suspended sediment from river floods reached the inner reef
area only occasionally, whereas after about 1870-following the
beginning of European settlement - a five- to tenfold increase in the
delivery of sediments is recorded with the highest fluxes occurring
during the drought-breaking floods. We conclude that, since European
settlement, land-use practices such as clearing and overstocking have
led to major degradation of the semi-arid river catchments, resulting
in substantially increased sediment loads entering the inner Great
Barrier Reef.
This data set consists of Ba/Ca ratios in long-lived Porites coral
from Havannah Reef and Pandora Reef as a proxy for Burdekin river
sediment fluxes to the inner Great Barrier Reef. Weekly and monthly
Burdekin River flow data also reported. 
