title: Assessment of biotic response to heavy metal contamination in Avicennia marina mangrove ecosystems in Sydney Estuary, Australia.
abstract: Mangrove forests act as a natural filter of land-derived wastewaters along industrialized tropical and sub-tropical coastlines and assist in maintaining a healthy living condition for marine ecosystems. Currently, these intertidal communities are under serious threat from heavy metal contamination induced by human activity associated with rapid urbanization and industrialization. Studies on the biotic responses of these plants to heavy metal contamination are of great significance in estuary management and maintaining coastal ecosystem health. The main objective of the present investigation was to assess the biotic response in Avicennia marina ecosystems to heavy metal contamination through the determination of metal concentrations in leaves, fine nutritive roots and underlying sediments collected in fifteen locations across Sydney Estuary (Australia). Metal concentrations (especially Cu, Pb and Zn) in the underlying sediments of A. marina were enriched to a level (based on Interim Sediment Quality Guidelines) at which adverse biological effects to flora could occasionally occur. Metals accumulated in fine nutritive roots greater than underlying sediments, however, only minor translocation of these metals to A. marina leaves was observed (mean translocation factors, TFs, for all elements <0.13, except for Mn). Translocation factors of essential elements (i.e., common plant micro-nutrients, Cu, Ni, Mn and Zn) were greater than non-essential elements (As, Cd, Co, Cr and Pb), suggesting that A. marina mangroves of this estuary selectively excluded non-essential elements, while regulating essential elements and limiting toxicity to plants. This study supports the notion that A. marina mangroves act as a phytostabilizer in this highly modified estuary thereby protecting the aquatic ecosystem from point or non-point sources of heavy metal contamination.
authors.affiliation: School of Geosciences, University of Sydney, Sydney, NSW 2006, Australia. Electronic address: bibhash12@gmail.com.
authors.forename: Bibhash
authors.initials: B
authors.lastname: Nath
authors.affiliation: School of Geosciences, University of Sydney, Sydney, NSW 2006, Australia; Department of Environmental Science, University of Calcutta, Kolkata 700 019, West Bengal, India.
authors.forename: Punarbasu
authors.initials: P
authors.lastname: Chaudhuri
authors.affiliation: School of Geosciences, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Gavin
authors.initials: G
authors.lastname: Birch
mesh_terms: D001315:Australia; D032407:Avicennia / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D017753:Ecosystem; D004784:Environmental Monitoring; D063366:Estuaries; D019015:Geologic Sediments / Q000737:chemistry; D019216:Metals, Heavy / Q000032:analysis / Q000378:metabolism*; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry
chemical_list: D019216:Metals, Heavy
keywords: Avicennia marina; Bio-concentration factors; Leaves; Sediments; Trace elements; Translocation factors