RESUMEN
Research into sediment-seagrass tissue metal relationships has been undertaken in Sydney estuary due to the recognized role contamination plays in threats to seagrass health. Seagrass (Halophila ovalis) leaf tissue concentrations are elevated in Cu, Pb and Zn and contain the highest reported root Cr concentrations. Seagrass metal concentrations were significantly different between species H. ovalis and Zostera capricorni; between root and leaf tissue; and between sampling locations. Greatest tissue enrichment was for Pb, however metals were not enriched in seagrass relative to surficial sediment. Fine and total sediment metal concentrations were temporally consistent between collection years 2013/15, whereas root tissue metals changed between years and sites and leaf metal contents were temporally inconsistent. Extractable metal concentrations in fine sediment (<62.5⯵m) showed moderate significant correlation with root tissue and a weak significant relationship with leaf tissue, whereas total sediment metal showed no such relationships. Management implications are provided.
Asunto(s)
Sedimentos Geológicos/análisis , Hydrocharitaceae/química , Metales/análisis , Contaminantes Químicos del Agua/análisis , Australia , Ecosistema , Ecotoxicología , Monitoreo del Ambiente , Estuarios , Hydrocharitaceae/efectos de los fármacos , Hydrocharitaceae/metabolismo , Metales/farmacocinética , Metales Pesados/análisis , Hojas de la Planta/química , Hojas de la Planta/efectos de los fármacos , Raíces de Plantas/química , Raíces de Plantas/efectos de los fármacos , Especificidad de la Especie , Contaminantes Químicos del Agua/farmacocinética , Zosteraceae/química , Zosteraceae/efectos de los fármacos , Zosteraceae/metabolismoRESUMEN
Seagrass (Zostera capricorni) tissue metal concentrations in Sydney estuary are some of the highest reported for urban environments. A strong declining metal (As, Co, Cr, Cu, Mn, Pb and Zn) concentration gradient in fine sediment from highly modified to the near-pristine estuarine environments was matched by a concurrent and statistically significant, moderately strong, relationship with declining metal concentrations for leaf, rhizomes and root tissue types. Leaf tissue more consistently expressed metal concentration uptake from sediment. Rhizome tissue contained the highest concentrations for all metals, except Mn, while leaf concentrations were higher for Cr and Zn and roots were more elevated in Cr and Pb. Tissue Cr, Pb and Zn were close to background for reference sites for leaves. Maximum tissue enrichment over background was 25, 19, 47 and 8 times for Cr, Cu, Pb and Zn. Bio-sediment accumulation factors were generally <1 for all metals.