Year: 2026
Type: article
Abstract: Understanding rising atmospheric CO2 effects on the chemistry of the world’s ecosystems remains nascent. CO2 dissolved in water forms carbonic acid, thereby lowering pH (ocean acidification [OA]). Diatoms, which generate 40% of ocean primary productivity, depend on dissolved silicon to construct their silica frustules; lower pH reduces silica (SiO2) solubility in seawater. Recent experiments document enhanced silica sedimentation under elevated CO2, implying reduced Si recycling and availability to support diatom production at the ecosystem scale. We tested this hypothesis using long-term data from a productive Pacific coastline undergoing rapid pH decline. Over two decades, as pH declined, dissolved Si:N and water column chlorophyll concurrently declined strongly. Accounting for variation in potential Si transport vectors did not change these relationships. Our results support the OA Si loss hypothesis and indicate that this process is already ongoing in some productive ocean regions, with implications for the carbon cycle, coastal food webs, and human well-being. Long-term CO2-generated declines in ocean pH block recycling of silicon, an essential nutrient for diatom-driven ocean production. Associated reductions in chlorophyll and plankton-feeding fish reveal a novel CO2 impact on marine ecosystem health.
Source: Nature Communications
Institutions: University of Chicago, Duke University, University of Michigan
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $6,990
Awards: LTREB Renewal: Ecological Dynamics in an Experimentally-Tractable Natural Ecosystem, Field Parameterization and Experimental Tests of the Neutral Theory of Biodiversity, LTREB: Ecological Dynamics in an Experimentally-Tractable Natural Ecosystems, Variability and the Population Biology of Marine Organisms, The role of microbes in driving productivity and carbon fixation in seaweeds, Eco-Evolutionary Response to the Scale of Temporal Environmental Fluctuation, Collaborative Research: The Role of Regenerated Nitrogen for Rocky Shore Productivity, Effects of Demography and Genetics on Extinction in Small Populations: Experiments with an Exploited Kelp, CAREER: Scientific Computing for a New Generation of Ecologists, Testing Indicators of State Flips Along Spatial and Temporal Gradients of Environmental Conditions
OpenAlex ID: W7223188335