Dr Arie Spyksma1, Miss Celia Balemi1, Dr Paul Caiger1, Miss Kelsey Miller1, Dr Nick Shears1
1University Of Auckland, , New Zealand
Marine heatwaves (MHWs) are increasing in frequency, duration and intensity across the globe, with major impacts to marine ecosystems as a result. North-eastern New Zealand has shown a trajectory towards warming water temperatures over the past two decades and has experienced a number of short-term (<40 days) MHWs; however, few impacts associated with these events have been documented. Between November 2021 and June 2022, this region suffered a record-breaking MHW, with areas such as the partially-enclosed Hauraki Gulf experiencing continuous MHW conditions, averaging 1.8°C above normal (peaking at 3.6°C) for more than 200 days. Rocky reef monitoring programmes across the Gulf throughout the duration of this MHW event revealed an episode of sponge necrosis and die-off spanning a spatial scale (1000s of km2) not seen before. Multiple species were impacted including two massive, structurally important species; Ecionemia alata and Stelletta conulosa. Other observations include extensive blooms of red filamentous algae and benthic dinoflagellates (Ostreopsis siamensis), and rapid expansion of an invasive subtropical ascidian (Symplegma brakenhielmi). Here we highlight findings associated with this unprecedented MHW and discuss implications for rocky reef communities in an increasingly warm ocean.
Presentation Slides – Arie Spyksma
Biography:
Arie is a Research Fellow at the Leigh Marine Laboratory where he focuses on leveraging new and emerging technologies for improving ecosystem monitoring and scientific visualisation. Arie’s PhD research focussed on trophic interactions within rocky reef systems and at present he is working on monitoring and understanding ecosystem threats associated with warming water temperatures across north-eastern New Zealand.
