Prof. Chris Battershill1, Dr Sam McCormack1, Prof Brendan Hicks1, Dr Terry Isson1, Ms Nicole Sturgess1, Ms Fenna Beets1, Professor Michelle Kelly2
1University of Waikato, Tauranga, New Zealand, 2NIWA, Auckland, New Zealand
Nearshore marine biogeography and ecology of Aotearoa New Zealand’s exposed west coast is not well understood, yet this region is likely to experience biodiversity assemblage shifts in a fast changing oceanic climate. A detailed examination of reef systems focusing on sponge communities around Taranaki, was undertaken to provide a robust biogeographic baseline for future comparison. Attention was also paid to the condition of catchments that discharge into these coastal reef systems, particularly in terms of potential food sources and the deleterious effects of fine sediment discharges (also increasing in our changing climate). The demography of sponges characterising the reef systems was examined together with establishing trophic cascades using stable isotope analyses.
Taranaki sponge distribution was found to be patchy over small spatial scales with a high level of endemism in the sponge fauna. A total of 127 species were recorded from stations around the Taranaki coast. Approximately 9.6 sponge species per m2 exist in some locations. The quality of fresh water discharge from catchments had a major influence on sponge diversity and biomass along coastal regions influenced by river discharges. In catchment systems that were not unduly compromised by sediment, 40% of the sponge diet was derived from freshwater bacteria. Some sediment impacted reefs supported higher numbers of unique sponge species. Species associations are both warm and cold temperate, reflecting the varying current systems influencing this coastline. Within this backdrop, sponge density and biomass reflected the extent of food delivery with a non-linear, inverse relationship between potential food content of river discharges and fine sediment loading. The resultant species assemblage and biomass supported at any articular reef site, reflects the trade off between metabolic efficiencies in acquiring energy and expending it staying free of sediments, atop the base ‘suitability’ of various taxa/morphologies to live in a high sediment environment.
Presentation Slides – Chris Battershill
Biography:
Chris Battershill enjoyed twelve years with the Marine Resources and Biodiversity Teams at the Australian Institute of Marine Science, focusing on conservation, trophic cascades, oil&gas industry sustainability, aquaculture and biodiscovery. An MSc in environmental toxicology led to a PhD in reef ecology at Auckland University, followed by a 3 year National Cancer Institute (US) Research Fellowship in medicinal biodiscovery. This led to Post-Doctoral research and an AIMS career, with focus on the chemical ecology of marine invertebrates that produce biomedicinal leads. He is now the inaugural Professorial Chair of Coastal Science at the University of Waikato.
