Delineation of sediment sources to a coastal wetland in the Great Barrier Reef catchment: influence of climate variability and land clearing since European arrival
Grant B. Douglas A H , Mio Kuhnen B , Lynda C. Radke C , Gary Hancock D , Brendan Brooke C , Mark J. Palmer E , Tim Pietsch D , Phillip W. Ford D , Michael G. Trefry A F and R. (Bob) Packett GA CSIRO Land and Water, Centre for Environment and Life Sciences, Private Bag No. 5, Wembley, WA 6913, Australia.
B Department of Earth and Marine Sciences, Australian National University, Canberra, ACT 0200, Australia.
C Petroleum and Marine Division, Geoscience Australia, GPO Box 378, Canberra, ACT 2601, Australia.
D CSIRO Land and Water, Black Mountain Laboratories, GPO Box 1666, Canberra, ACT 2601, Australia.
E CSIRO Mathematical and Information Sciences, Centre for Environment and Life Sciences, Private Bag No. 5, Wembley, WA 6913, Australia.
F School of Earth and Environment, University of Western Australia, Crawley, WA 6009, Australia.
G Queensland Department of Natural Resources and Water, Rockhampton, PO Box 1762, Rockhampton, Qld 4700, Australia.
H Corresponding author. Email: grant.douglas@csiro.au
Environmental Chemistry 7(2) 190-206 https://doi.org/10.1071/EN09089
Submitted: 10 July 2009 Accepted: 22 December 2009 Published: 22 April 2010
Environmental context. Undisturbed sediments provide a record to past events in a catchment. In this study we examine changes in sources of sediment and their variation over the past century due to changes in climate and extensive modification of the catchment after European settlement. We also highlight how multiple lines of forensic evidence acquired from the sediments can be used to reconstruct catchment history over a range of timescales.
Abstract. Enhanced delivery of sediment and nutrients to the Great Barrier Reef has the potential to profoundly influence ecological processes in this natural icon. Within the Fitzroy River Basin (FRB) of north-eastern Australia, natural impoundments such as Crescent Lagoon provide an invaluable archive of accumulated sediment that can be dated using multiple techniques to reconstruct the history of sediment export. During the last century, net rates of accumulation of sediment remain similar; however, large variations in sediment sources are apparent. A major sedimentary and geochemical discontinuity is present between ~45 to 29 years before present. Within this time interval a redox front is preserved corresponding to a change in organic matter influx; C3 plant detritus derived from the onset of broadscale agriculture within the FRB provided an assimilable carbon source resulting in more reducing conditions within the sediments. Statistical correlations demonstrate a notable correspondence between some sediment fractions supporting the notion of a short-lived disturbance to the sedimentation regime in the 1960–70s.
Additional keywords: geochemistry, lagoon, sediment.
Acknowledgements
The authors gratefully acknowledge the assistance of several people who contributed to the project including: Professor Patrick De Deckker of the Australian National University R. Noble and P. Voltz, Queensland Department of Natural Resources and Water, for logistical and sampling assistance; fellow researchers within the Cooperative Research Centre For Coastal Zone, Estuary & Waterway Management and T. Pinchand, CSIRO Land and Water, for laboratory assistance.
[1]
P. M. Outridge ,
G. A. Stern ,
P. B. Hamilton ,
J. B. Percival ,
R. McNeely ,
W. L. Lockhart ,
Trace metal profiles in the varved sediment of an Arctic lake.
Geochim. Cosmochim. Acta 2005
, 69, 4881.
| Crossref | GoogleScholarGoogle Scholar |
CAS |
[Verified 18 January 2010]
[4]
G. B. Douglas ,
P. W. Ford ,
M. R. Palmer ,
R. M. Noble ,
R. Packett ,
Fitzroy River Basin, Queensland, Australia. I. Identification of sediment sources in impoundments and flood events.
Environ. Chem. 2006
, 3, 364.
| Crossref | GoogleScholarGoogle Scholar |
CAS |
[Verified 18 January 2010]
[10]
[11]
[12]
[13]
F. Oldfield ,
P. G. Appleby ,
R. W. Battarbee ,
Alternative 210Pb dating: results from the New Guinea Highlands and Lough Erne.
Nature 1978
, 271, 339.
| Crossref | GoogleScholarGoogle Scholar |
CAS |
[Verified 18 January 2010]
[34]
[35]
A. S. Murray ,
R. Marten ,
A. Johnston ,
P. Martin ,
Analysis for naturally occurring radionuclides at environmental levels by gamma spectrometry.
J. Radioact. Nucl. Chem. 1987
, 115, 263.
| Crossref | GoogleScholarGoogle Scholar |
CAS |
[36]
K. M. Wong ,
Radiochemical determination of plutonium in seawater, sediments and organisms.
Anal. Chim. Acta 1971
, 56, 355.
| Crossref | GoogleScholarGoogle Scholar |
CAS |
PubMed |
[37]
D. J. Huntley ,
D. I. Godfrey-Smith ,
M. L. W. Thewalt ,
Optical dating of sediments.
Nature 1985
, 313, 105.
| Crossref | GoogleScholarGoogle Scholar |
[38]
[39]
J. M. Olley ,
T. Pietsch ,
R. G. Roberts ,
Optical dating of Holocene sediments from a variety of geomorphic settings using single grains of quartz.
Geomorphology 2004
, 60, 337.
| Crossref | GoogleScholarGoogle Scholar |
[40]
[41]