Plankton biodiversity in the Southern Ocean
Long-term monitoring of plankton is essential to understanding the impacts of climate change and ocean acidification on marine biodiversity and ecosystems. NIWA has begun a five–year project to map changes in the distribution of plankton in the Southern Ocean as part of a Ministry of Fisheries marine biodiversity programme.
Antarctic plankton are expected to be particularly sensitive and vulnerable to climate change and increased ocean acidity. Changes in plankton abundance, diversity, and distribution could have cascading effects through the marine ecosystem.
The Southern Ocean Continuous Plankton Recorder Survey coordinated by the Australian Antarctic Division has already identified significant changes in zooplankton composition in eastern Antarctic waters that could have a major impact on higher predators. As yet, western Antarctic waters south of New Zealand have not been well sampled.
5–year study using commercial fishing vessels
The Ministry of Fisheries is funding NIWA to fill this gap by collecting plankton data over five years between New Zealand and the Ross Sea, Antarctica. NIWA is collecting samples using a Continuous Plankton Recorder (CPR) towed behind a Sanford Ltd fishing vessel as it transits from Timaru to and from the Antarctic toothfish fishing grounds in the Ross Sea.
The CPR was successfully deployed from the San Aotea II in December 2008 and January/February 2009. This will be repeated each austral summer over the next four years and the data analysed — along with those from RV Tangaroa’s 2006 and 2008 Ross Sea voyages — to determine trends in plankton diversity, distribution, and abundance.
NIWA technician trained in zooplankton identification
To compare CPR data from year to year and with other surveys, they must be analysed according to strict protocols. NIWA technician Karen Robinson trained in the identification of zooplankton at the Australian Antarctic Division in Hobart with the assistance of a QEII Technical Training Award. She will be identifying the plankton from the surveys in collaboration with members of the Australian Antarctic Division.
The data will contribute to the Southern Ocean CPR Survey to provide an insight into unrecorded biodiversity and plankton distribution in the Southern Ocean. Results will ultimately contribute to our understanding of the effects of climate change and ocean acidification on ocean ecosystems.
Contact: Dr Julie Hall, NIWA Wellington
Southern Ocean Continuous Plankton Recorder Survey
Dr Julie Hall setting up the Continuous Plankton Recorder (Glen Walker, NIWA/NZ IPY-CAML)