"Reversal of eutrophication and cataclysmic, earthquake-driven changes to an estuarine ecosystem in southern New Zealand"
Monday, November 12, 2012 3:30 PM - 4:30 PM
Beginning of 4 September 2010, and continuing through much of 2011, a series of earthquakes of magnitudes up to 7.1 struck the Canterbury region of southern New Zealand over several months. The
central area of the city of Christchurch was largely destroyed and massive upheaval and liquefaction occurred through the area. The floor of the Avon-Heathcote estuary was tilted by up to 1m, up to
60% of the benthic surface was covered by liquefaction, and large amounts of raw effluent flowed into the estuary from damaged wastewater pipes. The estuarine ecosystem was dramatically changed with
different micro- and macro-algal dynamics, sediment structure and food web dynamics. Furthermore, there had been a diversion of Christchurch’s treated wastewater from the estuary to an ocean outfall
in early 2010, and so earthquake-driven effects were overlaid on this attempt at remediation after decades of eutrophication. The effects and changes to estuarine dynamics over the past year are
David Schiel is in the School of Biological Sciences at Canterbury University. He heads the Marine Ecology Research Group and is co-director of the Centre of Excellence in Aquaculture and Marine
Ecology (UC and the National Institute of Water and Atmospheric Research). He is a rocky shore ecologist who, through a series of unlikely events, heads a large project on estuarine recovery, made
even more unlikely because of the earthquakes that occurred during the study in 2010-11. He also co-leads a project on the recovery from a large oil spill on the NZ coast.