According to research published in Marine Ecology on July 29, 2026, single-celled algae diatoms experience altered growth, abundance, and elemental composition when ocean pH levels shift. Professor Sophie Leterme, director of the ARC Industry Transformation Training Centre for Biofilm Research and Innovation at Flinders University’s College of Science and Engineering, states that these microscopic changes threaten the foundations of aquatic food webs and impact deep-sea carbon capture.
Ocean Acidification Threatens Diatom Health and Marine Food Webs
Microscopic diatoms account for 40% to 50% of primary production in oceans. According to Professor Leterme, these organisms help export organic carbon to the deep ocean by fixing carbon dioxide from near-surface waters. However, rising carbon emissions are changing seawater chemistry. The dissolution of carbon dioxide into marine environments has caused a global pH drop of 0.1 units since the end of the Industrial Revolution, with values projected to fall another 0.3 to 0.6 units by the end of this century.
These shifting pH levels directly impact how planktonic algae absorb essential trace elements. Metals such as iron, zinc, and cadmium are vital for inorganic carbon acquisition in these organisms. When water temperatures rise and ocean acidification worsens, the physiology and functioning of these key bio-indicators are downgraded, risking widespread disruptions to marine food webs.
Did You Know? Diatoms live not only in oceans, lakes, and rivers, but even in damp soil, and they produce a significant portion of the oxygen in Earth’s atmosphere.
High-Tech Neutron Activation Analysis Reveals Metal Absorption Shifts
To investigate these complex physiological changes, researchers at Flinders University utilized seawater samples collected from South Australia’s Gulf St Vincent alongside specimens from the CSIRO algae collection. According to the study, the team performed experimental setups on specific microalgal species, namely Thalassiosira pseudonana and Nitzschia navis-varingica.
The study deployed highly sensitive neutron activation analysis, supported by ANSTO expertise. These experiments demonstrated how trace metal uptake by marine diatoms could shed light on how a wide range of other environmental elements are absorbed by other marine organisms. While higher concentrations and growth of diatoms might theoretically help pull down carbon dioxide levels, researchers caution that the ecological fallout of lower concentrations of major and trace elements remains poorly understood.
Developing Solutions for Marine Pollution and Carbon Sequestration
Understanding how these complex seawater processes function will guide practical mitigation strategies. Flinders researchers note that insights gained from this study could contribute to the development of novel biofilms designed to reduce shipping pollution in harbors. Furthermore, contextual research published in the Australian Journal of Maritime and Ocean Affairs emphasizes the importance of building knowledge for actionable outcomes.
As scientists race to map out the consequences of climate change on aquatic microbes, protecting these single-celled organisms remains central to preserving global oxygen production and maintaining efficient natural carbon sinks.
Frequently Asked Questions
What are diatoms?
Diatoms are microscopic, single-celled algae found in oceans, lakes, rivers, and damp soil that produce a large portion of Earth’s atmospheric oxygen.
How does ocean acidification affect diatoms?
Changes in ocean pH alter the growth, abundance, and elemental composition of diatoms, disrupting their ability to absorb trace metals like iron, zinc, and cadmium.
Why are diatoms important for carbon capture?
Diatoms account for 40% to 50% of primary marine production and help export organic carbon to the deep ocean by fixing carbon dioxide from surface waters.
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