New Research Sheds Light on the Mid-20th Century Industrial Deforestation Impacting Malaysian Borneo’s Coastal Reefs
A groundbreaking study led by the University of Leicester has unveiled a long-hidden narrative of industrial deforestation’s onset in Malaysian Borneo, as chronicled within the skeletons of massive corals thriving in nearby coastal waters. The team’s scientific expedition offers a pioneering method that combines marine chemistry and terrestrial environmental history, providing invaluable insights into how land-use changes beginning in the 1950s have profoundly influenced sediment dynamics and, consequently, the health of coral reef ecosystems.
Published in the prestigious journal Scientific Reports, this research leverages coral core samples retrieved from the Miri-Sibuti Coral Reef National Park, an ecologically significant marine reserve. By analyzing trace element ratios, notably barium to calcium (Ba/Ca), preserved in the calcium carbonate skeletons of Porites corals, researchers have established a detailed century-long timeline of sediment influx changes. This indirect yet powerful proxy reveals how industrial-scale deforestation accelerated soil erosion, leading to enhanced sediment discharge into adjacent marine systems.
The international research consortium, including experts from the United Kingdom, Malaysia, and Australia, employed advanced geochemical techniques to decode the historical environmental signals captured within the coral record. Professor Jens Zinke and his team initiated underwater sampling with pneumatic drills to extract multiple meters-long cores from large coral colonies situated at varying proximities from the primary river discharging into the coastal reef system. This stratified sampling approach ensured a robust spatial and temporal dataset connecting terrestrial activities to marine sedimentation patterns.
During the constraints imposed by the COVID-19 pandemic, the coral cores were transported to Curtin University’s John de Laeter Centre in Perth, Australia, where laser ablation inductively coupled plasma mass spectrometry was carried out under stringent laboratory conditions. This state-of-the-art method enabled the precise measurement of trace elements embedded within coral skeletons at exceptionally fine scales. The Ba/Ca ratio was of particular interest because barium is predominantly mobilized and transported by riverine sediments; thus, shifts in this ratio proxy sediment load variations driven by deforestation and land-use modifications upstream.
The geochemical data paint a compelling narrative: between 1900 and around 1950, Ba/Ca ratios remained consistently low, indicating minimal sediment influx and relatively stable soil erosion rates. However, post-1950 records reveal a sharp and sustained increase in Ba/Ca values. This rise coincides with the rapid industrial expansion of logging and agricultural operations within Borneo’s vast tropical forests. The findings mark 1950 as a pivotal turning point when large-scale mechanized deforestation began to alter land surfaces and accelerate soil mobilization into river systems.
This study not only bridges gaps in environmental historical data but also provides an innovative method to explore land-sea interactions in regions where conventional records are scarce or non-existent. Massive corals, due to their longevity and ability to incorporate environmental signals chemically, serve as natural archives, preserving multi-decadal to centennial records of terrestrial and marine interplay. Such archives are crucial for reconstructing human impacts on ecological systems amid the global challenges posed by land degradation and climate change.
Beyond tracing sediment loads, the research team is expanding the investigation to include the analysis of dissolved organic carbon fractions in coastal river waters. This complementary approach, undertaken by PhD candidate Hannah Kingsland, aims to unravel the complex biochemical exchanges occurring between deforested tropical landmasses and their adjacent marine ecosystems. Understanding these biochemical linkages is vital for formulating holistic conservation strategies, as both sediment and organic carbon fluxes influence coral health, reef vitality, and broader coastal marine biodiversity.
The research sheds light on the enduring consequences of deforestation beyond terrestrial boundaries, illustrating that the repercussions permeate into marine environments with lasting ecological ramifications. Former Leicester PhD student Walid Naciri emphasized that establishing baseline pre-deforestation environmental conditions was instrumental in accurately assessing anthropogenic disturbances’ magnitude. The evidence underscores the necessity for integrated ecosystem management that accounts for land-based activities’ downstream impacts on oceanic systems.
The implications of these findings are profound. As Dr. Arnoud Boom notes, this ‘fingerprint’ — etched chemically in coral skeletons — offers an unprecedented opportunity to track historical land-use changes and their cascading effects on coastal ecosystems. This knowledge equips policymakers and conservationists with critical data to prioritize interventions aimed at reducing sediment discharge, promoting sustainable land-use practices, and restoring tropical forests to enhance carbon sequestration and ecosystem resilience.
The timing of this deforestation onset record also aligns with broader global patterns of post-war industrial expansion and escalating demands for commodities such as palm oil and pulpwood. The study highlights the critical need for local and international stakeholders to foster alternative economic pathways that mitigate forest loss. Combined with reforestation initiatives, these efforts will be central to safeguarding both terrestrial and marine environments that communities and biodiversity depend upon.
In summary, this innovative research exemplifies how marine bioarchives can be harnessed to reconstruct anthropogenic environmental change over the past century. By unveiling the mid-20th century acceleration of industrial deforestation via coral Ba/Ca ratios, the study delivers compelling evidence that land-use change in tropical rainforests is intricately linked to sediment stress in coral reef ecosystems. These insights offer a vital scientific foundation for coordinated ecosystem management aimed at curbing deforestation, reducing sediment pollution, and preserving coral reefs amid escalating global environmental pressures.
Subject of Research: Industrial deforestation impact and sediment discharge in Malaysian Borneo revealed through coral geochemical archives
Article Title: Corals Ba/Ca records uncover mid-twentieth century onset of land use change associated with industrial deforestation in Malaysian Borneo
News Publication Date: 1-Jul-2025
Web References: 10.1038/s41598-025-06679-2
Image Credits: Walid Naciri
Keywords: Coral reefs, Coral calcification, Ocean chemistry, Seawater, Rainforests, Ecology
