Nutrient cycling


conceptual diagram of nutrient cycling process


Nutrients enter estuarine wetlands from neaby terrestrial areas dissolved in run-off or as particles of detritus Wetland pools exchange nutrients with other estuarine ecosystems when connected by water flow (such as run-off or high tides) (Sheaves et al, 2006)
Estuarine wetlands can act as sinks for nutrients by filtering run-off, thereby reducing the amount of nutrients entering sub-tidal zones. This process improves water quality and reduces the risk of eutrophication and algal blooms downstream. Flushing wetlands, however, may provide a source of nutrients to coastal waters (Alongi and McKinnon, 2005; Rassam et al, 2006) Crabs and other animals can transfer nutrients (often in the form of detritus) into and out of the sediment. (Pennifold and Davis, 2001; Thrush and Dayton, 2002)
Nutrients are exchanged with terrestrial areas (inluding nearby coastal areas and other continents) through animal movement. (Sheaves et al, 2006) Microbes recycle nutrients and exchange nitrogen with the atmosphere. (Dennison and Abal, 1999; Rassam et al, 2006)
Groundwater and riparian vegetation can play a significant role in reducing nitrogen entering streams, protecting downstream water quality (Rassam et al, 2006) Nutrients are exchanged upstream and downstream through water and animal movement
Nutrient cycling occurs within and between zones


  1. Alongi D.M. and McKinnon A.D. 2005, The cycling and fate of terrestrially-derived sediments and nutrients in the coastal zone of the Great Barrier Reef shelf, Marine Pollution Bulletin, Volume 51, Issues 1-4, Pages 239-252.
  2. Dennison, W.C., Abal, E.G. 1999, Moreton Bay Study: A Scientific Basis for the Healthy Waterways Campaign, South East Queensland Regional Water Quality Management Strategy, Brisbane, 246p.
  3. Pennifold, M., Davis, J., 2001, Macrofauna and nutrient cycling in the Swan River Estuary, Western Australia: experimental results, Hydrological Processes, Vol 12 (13) p2537-2553.
  4. Rassam, et al 2006 [in press]
  5. Thrush, S.F., Dayton, P.K., 2002, Disturbance to marine benthic habitats by trawling and dredging: Implications for marine biodiversity, Annual Review of Ecology and Systematics, 33, p449-474.
  6. Sheaves, et al 2006 [in press]