Depositional low velocity zones of intertidal and fringing mangroves in Darwin Harbour are ‘islands’ of high nutrient assimilation and processing.

Project: HDR ProjectPhD

Project Details

Description

Darwin Harbour is a large macro-tidal estuary in the wet-dry tropics of northern Australia. During low tide large expanses of mudflats which cover approximately 38 km2 are exposed and bounded by fringing mangrove forest that line a large proportion of the 1220km2 area of the estuary. Several waterways discharge to Darwin Harbour, the largest being the Blackmore and Elizabeth Rivers which form two major arms of the estuary. The harbour is a highly dynamic estuarine system by virtue of the tidal and seasonal extremes that prevail, with these factors playing an influential role in maintaining productive biogeochemical processes that provide important ecosystem services. Given the significant extent of intertidal and mangrove sediments in Darwin Harbour it is proposed that these zones might be ‘islands’ or hotspots of nutrient assimilation and processing.
Darwin Harbour is oligotrophic maintaining low nutrient levels and phytoplankton biomass, with highly productive fringing mangrove zones. Preserving and understanding the key mechanisms that maintain this enviable condition are important in the face of expected nutrient load increases with future development.
There is ongoing debate as to whether new DNA and RNA-based approaches to ecosystem functional assessment reflect actual rates of nitrogen turnover in the environment. This research will attempt to examine the abundance and activity of genes associated with nitrogen removal pathways and whether they are correlated to abiotic measures of nitrogen removal. An outcome will be an estimation of whether this approach can be used to assess the nitrogen removal capacity of these zones to mediate nitrogen loads and what seasonal or spatial factors might influence this.
StatusActive
Effective start/end date28/03/14 → …