1UGM Environmental Services

Eutrophication from nutrient over-enrichment is a serious problem for the coastal zone and the estuarine environment globally. Australian estuaries are generally oligotrophic, but assessing whether they are becoming more eutrophic over time is inhibited by a lack of long-term monitoring data. The Richmond River, Australia, provided an ideal example of estuary under anthropogenic pressure where the use of innovative palaeoecological techniques has been able to reconstruct changes in nutrient status over time. A core was extracted from a depositional area in the Richmond River, and several palaeoenvironmental techniques applied. Results of aquatic algae analysis show a strong indication that the total phosphorus levels in the Richmond River have fluctuated since 1940. Evidence also suggests that these fluctuations are most likely a function of climate. This study has successfully applied palaeolimnological techniques to the estuarine environment to produce information that can be used by environmental managers to aid decision making in relation to nutrient control for the Richmond River. This provides a case example of how this technique can be applied to assist management decisions in other Australian coastal zones