Porewater exchange drives trace metal, dissolved organic carbon and total dissolved nitrogen export from a temperate mangrove wetland

Sadat-Noori, Mahmood, and Glamore, William (2019) Porewater exchange drives trace metal, dissolved organic carbon and total dissolved nitrogen export from a temperate mangrove wetland. Journal of Environmental Management, 248. 109264.

PDF (Published Version) - Published Version
Restricted to Repository staff only

DOI: 10.1016/j.jenvman.2019.109264

View at Publisher Website: https://doi.org/10.1016/j.jenvman.2019.1...

Abstract

Porewater exchange is usually the least quantified process in delivering dissolved material from wetlands to coastal waters, although it has been recognised as an important pathway for the transport of trace metal, carbon and nutrient to the ocean. Here, surface water fluxes of dissolved manganese (Mn), iron (Fe), dissolved organic/inorganic carbon (DOC/DIC), total dissolved nitrogen (TDN) and phosphorous (TDP) were estimated from a temperate mangrove wetland (Kooragang Island, Newcastle, Australia). Radon (222Rn, a natural groundwater tracer) was used to develop a mass balance model to quantify porewater exchange rates and evaluate the contribution of porewater-derived dissolved material to the overall wetland surface water export. A 25-h time series dataset depicted a clear peak of Mn, Fe, TDN, DOC and radon during ebb tides which related to porewater discharge. Porewater exchange rates were estimated to be 14.0 ± 6.3 cm/d (0.18 ± 0.08 m3/s), mainly driven by tidal pumping, and facilitated by a large number of crab burrows at the site. Results showed that the wetland was a source of Mn, Fe, TDN and DOC to the adjacent river system and a sink for TDP and DIC. Surface water Mn, Fe, TDN and DOC exports were 4.0 ± 0.6, 6.6 ± 1.6, 23.9 ± 3.6 and 197.7 ± 29.7 mmol/m2 wetland/d, respectively. Porewater-derived Mn, Fe, TDN and DOC accounted for ~95, 100, 89 and 54% of the wetland surface water exports demonstrating its significant contribution. Our study indicates that temperate mangrove wetlands can be a major source of dissolved metal, carbon and nutrient delivery to coastal waters and that mangrove porewater exchange significantly contributes to this process.


Item ID:	78864
Item Type:	Article (Research - C1)
ISSN:	0301-4797
Keywords:	Estuary, Hunter River, Nutrient, Radon, Submarine groundwater discharge, Wetland hydrology
Copyright Information:	© 2019 Elsevier Ltd. All rights reserved.
Date Deposited:	20 Jun 2023 00:48
FoR Codes:	37 EARTH SCIENCES > 3707 Hydrology > 370703 Groundwater hydrology @ 50% 41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410402 Environmental assessment and monitoring @ 50%
SEO Codes:	18 ENVIRONMENTAL MANAGEMENT > 1802 Coastal and estuarine systems and management > 180201 Assessment and management of coastal and estuarine ecosystems @ 100%
	More Statistics

Actions (Repository Staff Only)

Item Control Page