Oyster shells and wastewater seaweed became building blocks for NGV's Plant Life

Sydney artist and material researcher Kate Scardifield works with scientists at the University of Technology Sydney's Climate Change Cluster on building materials grown from biological waste streams.

Biomasonry: press residual farmed seaweed and scrubbed oyster-shell waste into interlocking bio-bricks — a wall that grew in the sea.

Between October 2021 and January 2022 the team hand-processed over a tonne of fermenting wet seaweed and sun-bleached over a tonne of Pacific and Sydney Rock oyster shells — 500 kg of flat lids from a dispatch centre, 600 kg of cups straight from farms — curing them into solid interlocking blocks.

The fluted column 'Urgent Is The Rhythm' (90 cm diameter, nearly three metres tall) premiered at the 2022 Adelaide Biennial and now anchors Plant Life at NGV Melbourne (28 August 2026 – 7 February 2027, free entry).

A three-metre column in the Ian Potter Centre in Melbourne is built entirely from things that grew in the sea. 'Urgent Is The Rhythm', by Sydney artist and material researcher Kate Scardifield with scientists at the University of Technology Sydney's Climate Change Cluster, is biomasonry: interlocking blocks pressed from residual seaweed grown to filter wastewater in New South Wales and Queensland aquaculture, and oyster-shell waste from farms and dispatch centres along the NSW coast.

The sourcing was hand labour. A first batch of roughly 500 kilograms of shells — mostly flat Pacific oyster lids left after shucking — came from a commercial dispatch centre in southern Sydney; a second batch of around 600 kilograms of rounded cup shells came straight from the farms, each needing its own washing routine. Between October 2021 and January 2022 the team processed over a tonne of wet, fermenting seaweed and scrubbed, cleaned and sun-bleached over a tonne of shells, pressing and curing them into more than a hundred solid, stable bio-bricks.

Shells in architecture are an old idea: burnt oyster lime survives in the mortar of some of Sydney's earliest colonial buildings, and the shell middens at Tubowgule — today's Bennelong Point — once stood an estimated ten to twelve metres high. The column premiered at the 2022 Adelaide Biennial of Australian Art and now anchors Plant Life: The Nature of Design at NGV Melbourne, beside speculative drawings by Edition Office imagining whole buildings cultivated from algae.

Scardifield's blocks open the free-entry show, which gathers fungi-grown leather, hemp fibreboard, plant-based bioplastics, an RMIT-commissioned mycelium fire-retardant jacket carrying OEKO-TEX STANDARD 100 certification, and a mosque facade woven from 200 kilometres of reclaimed date-palm fibre rising 12.5 metres. As she puts it, carbon talk is usually abstract; her blocks give carbon a weight you can stand next to.

The seaweed is grown to filter wastewater and drinks in carbon dioxide as it goes — the material starts life doing environmental work.

Oyster shells from farms and dispatch centres were heading to landfill; their calcium carbonate makes up more than 90 percent of a shell.

Shell-in-mortar is a colonial-era technique, so the material revives a proven craft rather than inventing one from nothing.

The column makes an abstract argument physical: visitors stand next to the weight of carbon that the talk usually loses.

Waste streams carry their own story: a building block made from dinner-plate leftovers gives carbon talk a weight you can stand next to.

Biomasonry is not on hardware shelves yet, as the article is careful to say. At NGV the work sits in a show whose curatorial arc runs from ancestral plant knowledge through the petrochemical century to today's regenerative designers — built around the question of whether the materials of the future are already growing around us.