Baseline benthic fluxes - supporting sediment quality monitoring of Darwin Harbour 2025
Details:
Title
Baseline benthic fluxes - supporting sediment quality monitoring of Darwin Harbour 2025,
Creator
Fortune, J,
Maijid, M,
Issued by
Northern Territory. Department of Lands, Planning and Environment. Ecosystem Management Group. Flora and Fauna Division,
Sponsored by
INPEX-operated Ichthys LNG Project,
Collection
E-Publications,
PublicationNT,
E-Books,
Report No. 15/2026,
Department of Lands, Planning and Environment Technical Report No. 15/2026,
Date
2026,
Location
Darwin Harbour,
Abstract
Darwin Harbour is a tropical macrotidal estuary in the Northern Territory of Australia. The Harbour is flanked by a mix of urban estate, commercial marine and onshore gas processing and dispersed with tracts of intact mangrove forest. Notwithstanding growing development pressures in Darwin Harbour, water and sediment quality remain largely in very good condition. However, the influence of localised impacts on intertidal sediments and their function have recently been emphasised (Fortune et al. 2022; Fortune et al. 2024; Radke et al. 2025). The course of future development around Darwin Harbour warrants the collection of baseline sediment quality data to support the direction of sustainable management and underpin future monitoring and management measures. Conventional sediment indicators such as metals/metalloids, hydrocarbons and other contaminants of concern have long held place in routine monitoring programs. This study in 2025 repeats baseline benthic flux measures across intertidal sediments of Darwin Harbour to acquire a first order evaluation of nutrient and metabolic fluxes as a potential measure of sediment function. In the absence of measured N2 (nitrogen gas) fluxes — representing the important final removal of nitrogen across the benthic-pelagic interface to the atmosphere, we adopted the use of a genomic indicator for denitrification. The use of qPCR to measure nosZ gene abundance allows us to quantify denitrifiers in the microbial community of sediments. This gene can provide useful insight into functional activity of microbial communities of sediments and key environmental drivers that dictate community shift and corresponding function,
Notes
Made available by via Publications (Legal Deposit) Act 2004 (NT),
Acknowledgement: This report was funded by the INPEX-operated Ichthys LNG Project. We are grateful to the reviewers. We thank the Australian Institute of Marine Science (AIMS) Townsville and Environmental Analysis Laboratory (EAL) Southern Cross University, NSW and Charles Darwin University (BNA laboratories) for their support with chemical and qPCR analysis. Thanks to Matthew Majid, Flora, Fauna Division for field and lab support.,