Dong, Bohao, Prendergast, Amy, and Ulm, Sean (2026) One giant clam contains a month‑by‑month diary of the Great Barrier Reef’s climate 200 years ago. The Conversation, 29 September 2026.

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Abstract

[Extract] As the world’s largest living bivalve, Tridacna gigas can reach 1.2 metres, weigh more than 200 kilograms and live for over a century. Across their long lives, these clams record their daily life in their shells, creating an autobiographical shell diary.

In our new research, we read one of these shell diaries to reconstruct month-by-month climate conditions at Jiigurru (also known as the Lizard Island Group), in the northern Great Barrier Reef.

The shell’s story reveals that, before widespread industrial-era warming, Jiigurru’s summers were cooler than today, while winters were surprisingly similar.

Item ID:	94075
Item Type:	Article (Commentary)
ISSN:	2201-5639
Keywords:	Giant clam; Quaternary; Holocene; Past climate; Sclerochronology; Isotope; ENSO
Copyright Information:	Copyright © 2010–2026, The Conversation Media Group Ltd. Creative Commons — Attribution/No derivatives licence.
Funders:	Australian Research Council
Projects and Grants:	ARC Centre of Excellence for Australian Biodiversity and Heritage (CE170100015), ARC Centre of Excellence for Indigenous and Environmental Histories and Futures (CE230100009)
Date Deposited:	29 Sep 2026 04:23
FoR Codes:	37 EARTH SCIENCES > 3709 Physical geography and environmental geoscience > 370905 Quaternary environments @ 50% 43 HISTORY, HERITAGE AND ARCHAEOLOGY > 4301 Archaeology > 430101 Archaeological science @ 50%
SEO Codes:	19 ENVIRONMENTAL POLICY, CLIMATE CHANGE AND NATURAL HAZARDS > 1905 Understanding climate change > 190502 Climate variability (excl. social impacts) @ 50% 13 CULTURE AND SOCIETY > 1307 Understanding past societies > 130703 Understanding Australia’s past @ 50%
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