Bay of Bengal Waters Warmed and Acidified Since 1960
Researchers found rising temperatures and declining pH levels significantly altered the marine environment.
Updated on Oct. 3, 2026 in Environmental
Live Poll
Should your local government prioritize policies that address climate-driven changes in the regional marine environment?
A study published on September 2, 2026, revealed that the upper 50 metres of the Bay of Bengal warmed by up to 2.2°C between 1960 and 2020. During this period, surface pH levels dropped from a range of 8.3-8.4 to 8.1-8.2, driven by rising atmospheric carbon dioxide.
Why it matters
The acidification of seawater is caused by the absorption of atmospheric carbon dioxide, which creates carbonic acid. This process alters the acoustic properties of the ocean, potentially increasing noise pollution and disrupting the feeding behaviors of marine animals.
Researchers compared 1963 International Indian Ocean Expedition data with 2019 Sagar Maitri expedition measurements. The study identified that a decrease of 0.1 pH units can reduce underwater sound absorption by 10% to 12%.
The players
Ocean Dynamics
This peer-reviewed scientific journal published the research study detailing the environmental shifts in the Bay of Bengal.
The details
By comparing historical data with modern measurements, scientists tracked a heat storage increase of 0.018 × 10 joules per square metre per decade. While the upper layers warmed, the study noted cooling trends in deeper waters between 100 and 200 metres, alongside an average barrier layer thickness of 32 metres.
Timeline
1960-2020 was the primary period for tracking temperature and pH records.
1963 marked the initial collection of historical data during an expedition.
2019 was when modern measurements were collected for the study.
September 2, 2026, is the publication date of the research findings.
The Big Picture
This study extends the longitudinal data initially established by the International Indian Ocean Expedition by comparing it with modern 2019 findings. These findings highlight how legacy scientific datasets are vital for identifying the long-term impact of rising carbon dioxide on regional ocean health.
Increased ocean acidity and altered acoustic environments may disrupt marine food chains, potentially affecting commercial fishing yields in the region. Scientists suggest these changes could eventually force revisions to marine management and conservation policies.
The takeaway
Ocean acidification is a pervasive process that fundamentally changes the physical chemistry of our seas. Protecting marine biodiversity requires understanding that even small shifts in pH can have cascading effects on the underwater soundscape.
Further reading
For more on shifts in marine ecosystems, visit the Environmental section.
Live Poll
Should your local government prioritize policies that address climate-driven changes in the regional marine environment?
