Cassiopea sp. as biomonitors of waters contaminated by herbicides/insecticides
My MSc research is focused on the use of Cassiopeia sp. as a biomonitor of waters contaminated by herbicides and insecticides. Waterways of Australia and other parts of the world are often polluted with metals and insecticides that are washed into rivers during periods of heavy rain. These perturbations can, in turn, affect the biota of rivers, estuaries and marine waters. Herbicides are commonly transported into rivers, generally originating from preventative measures used in agriculture. In North Queensland, for example, herbicides are commonly used for weed control and are often flushed into major drainage areas. Short-term experiments have demonstrated that herbicides can affect the growth of coastal jellyfish and can have a major impact on symbiotic algae that the jellyfish require for growth. The objective of this study is to determine the impact of herbicides on the jellyfish Cassiopea sp. and its symbiotic zooxanthellae as well as to determine if herbicide exposure impairs statolith count (what is used to age Cassiopea sp.). The longer term effect on zooxanthella are poorly understood. Cassiopea sp. will be subjected to long term pulses (14-days exposure) of single insecticides and combination of insecticides to determine how this affects number of zooxanthellae, the photosynthetic efficiency of the jellyfish and growth of the jellyfish. In some cases, pollutants can cause jellyfish to shrink, but there is a poor understanding of potential recovery on a scale of weeks to months. After the long-term pulse of herbicide exposure, jellyfish will be monitored for 28-days post exposure to determine herbicide effect.