Dong, Bohao, Prendergast, Amy, Ulm, Sean, Shirai, Kotaro, Drysdale, Russell, Mcniven, Ian, Levchenko, Vladimir, Wong, Henri, Meekan, Mark, Nguurruumungu Indigenous Corporation, and Walmbaar Aboriginal Corporation RNTBC (2026) Seasonal palaeoenvironmental variability during pre-industrial times revealed by a Southern Hemisphere Tridacna shell. Global and Planetary Change, 267. 105717.

Preview	PDF (Published Version) - Published Version Available under License Creative Commons Attribution. Download (20MB) | Preview
	Other (Supplementary Table S1) - Supplemental Material Download (12kB)
	Other (Supplementary Table S2) - Supplemental Material Download (107kB)

Abstract

The end of the Little Ice Age (LIA) represents a key pre-industrial climate interval, marking the final major cooling phase before widespread anthropogenic warming after the mid-nineteenth century. However, high-resolution evidence for this transition remains dominated by Northern Hemisphere archives, limiting understanding of how low-latitude marine environments in the Southern Hemisphere responded to late-LIA climate variability. Here, we analysed a Tridacna gigas shell that lived for approximately 30 years during the early 1800s to provide a high-resolution 30-year snapshot of environmental variability at Jiigurru (Lizard Island Group) in the northern Great Barrier Reef (GBR), tropical Southern Hemisphere. Stable isotope records (δ18O, δ13C) from both the inner and outer shell layers were applied to reconstruct SST, precipitation variability, and local ENSO-like events. Our results suggest that cooling associated with the LIA extended to the northern GBR. Under a constant modern SSS-derived δ18OSeawater baseline, reconstructed SSTs were ∼ 0.9–1.2 °C lower than modern instrumental records, a monthly SSS-corrected sensitivity reconstruction reduced this estimate to ∼0.6–0.9 °C. These results suggest that late-LIA cooling at this tropical Southern Hemisphere site was smaller in magnitude than many Northern Hemisphere reconstructions. Shell δ13C exhibited pronounced seasonal variability, consistent with the precipitation-related hydroclimatic seasonality. Statistical analyses reveal pronounced two- to three-year periodicities in both SST and hydroclimatic variability, with more frequent El Niño-like events in the late 1700s and stronger La Niña-like conditions in the early 1800s. This 30-year Tridacna record therefore provides a rare seasonal marine archive for evaluating Southern Hemisphere climate variability during the terminal LIA.

Item ID:	94070
Item Type:	Article (Research - C1)
ISSN:	1872-6364
Keywords:	Giant clam; Quaternary; Holocene; Past climate; Sclerochronology; Isotope; ENSO
Copyright Information:	© 2026 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Funders:	Australian Research Council
Projects and Grants:	ARC Centre of Excellence for Australian Biodiversity and Heritage (CE170100015)
Date Deposited:	28 Sep 2026 01:26
FoR Codes:	43 HISTORY, HERITAGE AND ARCHAEOLOGY > 4301 Archaeology > 430101 Archaeological science @ 50% 37 EARTH SCIENCES > 3709 Physical geography and environmental geoscience > 370905 Quaternary environments @ 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%
Downloads:	Total: 3 Last 12 Months: 3
	More Statistics