22 Jan 2023

Kermadec Trench research expedition provides new ecological, geological insights

6:48 pm on 22 January 2023
Niwa marine ecologist Dr Dave Bowden

NIWA marine ecologist Dr Dave Bowden said the research team had made extraordinary new observations about the diversity and abundance of life in the ocean trenches. Photo: NIWA

Researchers taking part in a joint Chinese New Zealand research expedition to the Kermadec Trench, one of the deepest places in the world, says they have uncovered new insights into the ecological and geological processes of the area.

NIWA and Auckland Museum scientists and Chinese researchers conducted 15 dives on board the Institute of Deep-Sea Science and Engineering (IDSSE) deep ocean submersible, HOV Fendouzhe, which was deployed from the IDSSE's research vessel Tansuoyihao.

NIWA marine ecologist Dr Dave Bowden said they had made extraordinary new observations about the diversity and abundance of life in the ocean trenches.

"The imagery we were able to gather, and the sampling we were able to do are going to give us new understandings about how the food web works in the trench, with organic material from the upper ocean sustaining animal communities and exporting carbon to the depths.

"We saw some striking examples of food-fall, including dozens of deep-sea fishes and thousands of crustaceans gorging on the corpse of a large sunfish, and the intact vertebrae of a four-metre-long shark, long since stripped of all flesh."

IDSSE voyage leader Dr Peng Xiaotong said the voyage had also provided insight into the geological processes of the Kermadec subduction zone.

"This is where the Australasian continental plate overrides the Pacific plate, and it generates enormous forces that are released through volcanic and seismic events. Improved understanding [of] these processes is fundamental to managing the risk to New Zealand from such events."

IDSSE and NIWA are continuing to analyse the samples collected and say they expect to be able to get a better understanding of New Zealand's deepest environment, and the impacts that humans may have on it.