Skip navigation
Skip navigation

Tracing the source of sediment and phosphorus into the Great Barrier Reef lagoon

McCulloch, Malcolm; Pailles, Christine; Moody, Philip; Martin, Candace

Description

Neodymium and strontium isotopic systematics show that terrestrial phosphorus (P) entering the inner Great Barrier Reef (GBR) is dominated by the transport and dispersal of fine-grained basaltic soils. Soils derived from alkali basalts have high total P (3000-4000 mg/kg) and distinctive143Nd/144Nd isotopic signatures (εNd ∼+3 to +5), while the more common Palaeozoic granitic/metamorphic soils have much lower total P (300-600 mg/kg) and143Nd isotopic signatures ( εNd ∼-8). The nearshore...[Show more]

dc.contributor.authorMcCulloch, Malcolm
dc.contributor.authorPailles, Christine
dc.contributor.authorMoody, Philip
dc.contributor.authorMartin, Candace
dc.date.accessioned2015-12-13T22:34:55Z
dc.date.available2015-12-13T22:34:55Z
dc.identifier.issn0012-821X
dc.identifier.urihttp://hdl.handle.net/1885/76349
dc.description.abstractNeodymium and strontium isotopic systematics show that terrestrial phosphorus (P) entering the inner Great Barrier Reef (GBR) is dominated by the transport and dispersal of fine-grained basaltic soils. Soils derived from alkali basalts have high total P (3000-4000 mg/kg) and distinctive143Nd/144Nd isotopic signatures (εNd ∼+3 to +5), while the more common Palaeozoic granitic/metamorphic soils have much lower total P (300-600 mg/kg) and143Nd isotopic signatures ( εNd ∼-8). The nearshore environment (<5 km from the coast) is dominated by coarse-grained, granitic-derived fluvial detritus, while >20 km from the coast, carbonate-rich sediments with increasing contributions from basaltic components become more important. In the offshore sites adjacent to coral reefs, it is shown that basalt-derived sediments can account for >90% of the terrestrial P, although making up less than half of the total terrigenous detritus. Equilibrium phosphorus concentration measurements on the marine sediments indicate that P enters the GBR lagoon via a two-stage process. Firstly, during episodic flood events, P is transported into the GBR lagoon on P-retentive fine-grained suspended sediments, with only minor desorption of P occurring in the low-salinity flood plumes. Desorption of P mainly occurs over longer timescales, predominantly in regions of sediment anoxia, with release of PO43- directly into marine pore waters probably via reduction of ferric phosphates, and subsequent release into the water column by re-suspension. This process causes P depletion of the re-deposited sediments.
dc.publisherElsevier
dc.sourceEarth and Planetary Science Letters
dc.subjectKeywords: coral reef; degradation; lagoon; neodymium isotope; phosphorus; provenance; sediment transport; strontium isotope; Australia Degradation; Great Barrier Reef; Neodymium-strontium isotopes; Sediment phosphorus tracing
dc.titleTracing the source of sediment and phosphorus into the Great Barrier Reef lagoon
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume210
dc.date.issued2003
local.identifier.absfor040203 - Isotope Geochemistry
local.identifier.absfor050209 - Natural Resource Management
local.identifier.ariespublicationMigratedxPub5168
local.type.statusPublished Version
local.contributor.affiliationMcCulloch, Malcolm, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationPailles, Christine, QLD Department of Natural Resources and Mines
local.contributor.affiliationMoody, Philip, QLD Department of Natural Resources and Mines
local.contributor.affiliationMartin, Candace, College of Physical and Mathematical Sciences, ANU
local.bibliographicCitation.startpage249
local.bibliographicCitation.lastpage258
local.identifier.doi10.1016/S0012-821X(03)00145-6
dc.date.updated2015-12-11T09:24:49Z
local.identifier.scopusID2-s2.0-0038692070
CollectionsANU Research Publications

Download

There are no files associated with this item.


Items in Open Research are protected by copyright, with all rights reserved, unless otherwise indicated.

Updated:  19 May 2020/ Responsible Officer:  University Librarian/ Page Contact:  Library Systems & Web Coordinator