View Abstract

TERRESTRIAL SEDIMENT INFILLING OF MORETON BAY, AUSTRALIA - A LARGE, SUBTROPICAL EMBAYMENT. (E)

Moreton Bay is a large, shallow, sub-tropical embayment located in South East Queensland, Australia. Historically, the bay had maintained good water quality prior to European settlement, with large scale degradation occurring in the following 200 years. Currently, native vegetation remains intact in less than 25% of the 21,220 km2 catchment. The region can experience extreme rainfall events and widespread flooding particularly during strong La Niña episodes which, coupled with the catchment degradation and highly modified stream network, has resulted in elevated terrestrial sediment loading into Moreton Bay. A bay-wide survey in 2015 has shown the surface sediment composition of Moreton Bay to have changed dramatically, with mud sediments now dominating over 50% of the surface area. This represents an area of over 860 km2, more than double that established in 1970. Recent works within the bay have established, through cesium dating, that terrestrial depositions since 1840 have been approximately 1m in the most affected regions. To this end a series of shallow cores (≤1m) have been taken throughout the ~1500 km2 of Moreton Bay, in an effort to establish the deposition of terrestrial sediments particularly in recently expanded areas. Through three-dimensional interpolation of the sediment deposition, mud content, and bulk densities of the shallow core profiles a conservative estimate of the total deposition post-1970 is calculated, as well as the individual depositions of flood events which is relatively unknown.

Authors

Lockington, J. R., The University of Queensland, Australia, james.lockington@uq.net.au

Hutley, N. R., The University of Queensland, Australia, nicholas.hutley@uq.net.au

Grinham, A. R., The University of Queensland, Australia, a.grinham@uq.edu.au

Details

Poster presentation

Session #:041
Date: 02/28/2017
Time: 15:30 - 16:30
Location: Poster/Exhibit Hall

Presentation is given by student: Yes

PosterID: 361