Monitoring biological processes in Lake Rotorua following a rainstorm was the topic of the winning presentation at the University of Waikato’s Department of Biological Sciences’ 3rd Annual PhD Conference late last month.
PhD student Jonathan Abell was the first-prize winner, for his presentation titled: ‘Grey skies and a green lake: Biogeochemical processes in Lake Rotorua following a rainstorm’.
“Rainstorms represent disturbance events that can profoundly influence lake ecosystems. We undertook a high-frequency sampling programme to investigate what happened when there was a moderate (31 mm) rain event in the catchment of Lake Rotorua during August 2011. Water was sampled from a major inflow at hourly-frequency over three days to quantify transport of sediment and nutrients from a sub-catchment to the lake” says Abell.
“The results showed that the inputs of sediment and phosphorus from a single rainfall event over three days represented the equivalent of several weeks input at baseflow conditions. This has important implications for assessing nutrient load targets for the lake and means that the actual loads of sediment and phosphorus coming from at least some of the sub-catchments of Lake Rotorua may be substantially higher than first thought,” says PhD Supervisor Prof David Hamilton.
Abell explained that the work provides a foundation for future research that will use lake models to improve understanding of how episodic weather events affect lake ecology.
His research was completed in collaboration with the Bay of Plenty Regional Council and forms part of a major investment in lake research at the University of Waikato by the Ministry of Science and Innovation.
Abell was also one of ten students selected from amongst a group of international student applicants, to attend the International World Lakes workshop in Austin, Texas. The conference ran from 31 October to 4 November and was followed by a workshop at Lake Tahoe, CA.
Second place went to David Bradley with the topic, ‘Behavioural response of kokako to different dialects’, and third was awarded to Michael Pingram for his presentation on ‘Organic carbon sources in food webs of the lower Waikato River’. A Student’s Choice Award was also given out to Marie Brown for her presentation on ‘Compensating for ecological harm under the RMA’.
“The 20 minute presentations were of extremely high standard in their scientific creativity, terrific use of PowerPoint, and oral delivery,” says Chair of Biological Sciences, Brendan Hicks.