NZ pine pollen found 11,000m under the sea

  • 21/04/2017

Pollen from New Zealand pine forests has been shown to travel more than 1500km and could be changing remote deep-sea ecosystems, Niwa scientists say.

The scientists analysed sediment samples from the Kermadec and Tonga trenches and found pine pollen to be common.

It was particularly abundant in the deepest part of the Tonga Trench, some 10,800 metres down.

Marine biologist Dr Daniel Leduc says the trenches' steep topography is thought to funnel fine particles that sink from the surface waters of the sea.

That led to high accumulation of fine material, including pollen, at their deepest point.

The study, published in the journal Ecosystems, also found that areas where pollen is most abundant harbour the most life.

That suggests pollen may be a food source for some deep-sea organisms.

Dr Leduc says pine pollen was observed inside small, single-celled organisms called gromiids, which ingest the pollen and may derive nutritional benefits from it.

"This unsuspected source of land-derived food originating from exotic pine plantations may be altering deep-sea food webs," he said.

"Deep-sea ecosystems are typically characterised by very low availability of food sinking from the surface, and any new food source is likely to get used by the organisms that live in the sediments."

Pines produce particularly large amounts of pollen, which can travel long distances by wind and ocean currents, reaching areas where little or no other pollen is found.

Study co-author Dr Ashley Rowden said the accumulation of pine pollen could represent an unsuspected carbon sink.

"The gradual burial of pine pollen, part of which is highly resistant to decomposition, likely contributes to the sequestration of land-derived carbon."