This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Our oceans are in trouble, and new research from Flinders University shows how changes in diatoms (microalgae) could further undermine the foundation of aquatic food webs—as well as vital deep-sea carbon capture or sequestration. A new study published in Marine Ecology used high-tech methods to test common microalgal species and assess how various stressors, including acidification from excessive carbon dioxide (CO₂) levels, affect the absorption of trace metals and undermine the organisms' overall health and role in Earth's carbon cycle.
Although microscopic, single-celled diatoms that live in oceans, lakes, rivers and even damp soil are among the most important organisms on Earth because they produce a significant portion of the oxygen in the atmosphere. Diatoms account for 40% to 50% of primary production in oceans, and they contribute to the export of organic carbon to the deep ocean by fixing CO₂ from near-surface waters, says senior author Sophie Leterme, director of the ARC Industry Transformation Training Centre for Biofilm Research and Innovation at Flinders University's College of Science and Engineering. "We showed that changes in ocean pH can affect the growth, abundance and elemental composition of these diatoms," Leterme says.
"We need to investigate how these changes interact with various trace elements and can lead to broader ecological impacts, such as disruption to marine food webs, reduced carbon and silicon export, and increased microbial and nutrient activity." Rising carbon emissions affect pH levels in seawater, which can alter planktonic algae's absorption of trace elements, including iron, zinc and cadmium, that are essential for inorganic carbon acquisition. The dissolution of CO₂ into the ocean has already induced a global drop in pH of 0.1 units since the end of the Industrial Revolution, and values are expected to drop another 0.3 to 0.6 units by the end of this century. Diatom species are valuable bioindicators, often used to assess water quality and improve understanding of how ongoing ocean acidification and rising water temperatures degrade their physiology and functioning, with important consequences for the future of oceans.
The Flinders researchers say a better understanding of how these complex processes work in seawater will help identify solutions, including the development of novel biofilms to reduce shipping pollution in harbors. Using seawater samples collected in South Australia's Gulf St. Vincent and from the CSIRO algae collection, the researchers used highly sensitive neutron activation analysis in experimental setups involving the species Thalassiosira pseudonana and Nitzschia navis-varingica.
The experiments, supported by ANSTO expertise, showed how trace metal uptake by marine diatoms could apply to other marine organisms' absorption of a wide range of elements in the environment. "While a higher abundance and growth of diatoms might be beneficial to reduce carbon dioxide levels, the impact of lower concentrations of major and trace elements in the environment is not well understood." Sophie C. Leterme et al, The Impact of Ocean Acidification on the Sorption of Trace Metals by Diatoms, Marine Ecology (2026).
DOI: 10.1111/maec.70112 Swati Mestri holds a bachelor's degree in Electronics Engineering and has worked as a content editor since 2019. She has experience editing research documents across technology, health care, and materials science, and has a particular interest in technology and space. Full profile → Master's in physics with research experience.
Extract — continue reading at the source.
