18 May 2022

Our Changing World - Soft sediment seaweed

From Afternoons, 3:35 pm on 18 May 2022

Namrata Chand began diving in the coral reefs and warm, crystal-clear waters around her native Fiji. Diving to sample seaweed in Otago Harbour for her PhD is quite a different experience.

Namrata Chand prepares the equipment for Joe and Will to collect seaweed.

Namrata Chand prepares the equipment for Joe and Will to collect seaweed. Photo: RNZ / Claire Concannon

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‘I describe it as refreshing’ she says, ‘My first dive in Dunedin was in nine-degree water’.

Namrata (Nam) is studying a type of endemic (found only in New Zealand) red seaweed called Adamsiella chauvinii. Instead of attaching to rock like kelp, this seaweed species can grow on the soft sediment habitat found in Otago Harbour. It is thought to play important roles for this ecosystem including taking up nutrients from the water and providing habitat for a range of other seaweed species and marine creatures.

For her PhD research, Nam wants to understand where this red seaweed grows in the harbour and in what quantities, which nutrient, light and temperature conditions it likes, and what other seaweed species grow alongside it.

Claire Concannon joins Nam on her Autumn seaweed sampling trip to learn more about this ‘underdog of the ocean’.