The Palaeoenvironmental Implications of the Distribution of Intertidal Foraminifera in a Tropical Australian Estuary: a Reconnaissance Study
Modern intertidal foraminifera were investigated in a mangrove-lined microtidal distributary channel of the Barron River Delta (Cairns, Queensland, Australia). A monospecific assemblage of Trochammina inflata characterises saltmarsh environments (Biozone 1), whilst the more regularly inundated tidal flat is dominated (≥55%) by Ammonia beccarii (Biozone 2). Within the tidal flat environment, two foraminiferal subdivisions can be recognised; a high tidal flat assemblage (Biozone 2a) characterised by ≥70% Ammonia beccarii and low diversity, and a low tidal flat assemblage (Biozone 2b) with 55–65% Ammonia beccarii and high diversity (due to the settling out of small allochthonous species transported into the estuary from shelf environments). Foraminiferal distributions are also compared with tide levels estimated in the field. It appears approximately that Biozone 1 occurs between High Water and Mean High Water (MHW), Biozone 2a between MHW and Mean Tide Level (MTL), and Biozone 2b between MTL and Low Water. From this preliminary study, it is concluded that foraminifera possess significant potential in palaeoenvironmental studies of tropical Australian estuaries as indicators of intertidal environments, and also tidal levels.
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Document Type: Original Article
Affiliations: School of Geography and Development Studies, Bath Spa University College, Bath, UK
Publication date: March 1, 2001