Response of Marine Organisms to Ocean Acidification and Trace Metals

Ocean acidification, driven by the uptake of anthropogenic carbon dioxide, is reshaping marine ecosystems by altering seawater chemistry in ways that affect organismal physiology, community structure and biogeochemical cycles. Lower pH conditions influence the speciation and solubility of trace metals, often increasing their bioavailability and toxicity. Marine species—from plankton and shellfish to fish and benthic invertebrates—exhibit a range of responses, including disruptions to acid–base balance, enhanced oxidative stress, impaired growth, altered reproductive success and changes in feeding behaviour. At the molecular level, acidified conditions can compromise ionoregulation and damage cellular components through elevated reactive oxygen species. Ecologically, the combined stress of acidification and metal pollution threatens food-web dynamics, aquaculture viability and seafood safety, with implications for global food security and human health. Understanding these interactions is essential for informing mitigation strategies, adaptive management and policy decisions aimed at preserving marine biodiversity and ecosystem services under rapid environmental change.

Research from Nature Portfolio

Recent studies have revealed that ocean acidification can amplify the accumulation of cadmium in bivalve tissues, elevating the potential hazard associated with seafood consumption under projected pH decline scenarios. Parallel investigations have demonstrated that lowered pH enhances copper toxicity in key benthic invertebrates by shifting metal speciation and weakening epithelial barriers, leading to increased cellular damage and DNA strand breaks. Together, these foundational works establish that acidified seawater not only facilitates greater metal influx via disrupted ion channels but also interacts with species-specific acid–base regulation mechanisms, resulting in variable vulnerability across taxa and life stages.

Response of Marine Organisms to Ocean Acidification and Trace Metals publication trend

The graph below shows the total number of articles in response of marine organisms to ocean acidification and trace metals across all publications each year (not limited to Nature Index journals).

Technical terms

Ocean acidification: The reduction in seawater pH and alteration of carbonate chemistry resulting from increased absorption of atmospheric CO₂.

Trace metals: Metallic elements present at low concentrations in seawater, some of which are essential micronutrients while others are toxic at elevated levels.

Speciation: The distribution of a chemical element among different molecular or ionic forms, which determines its reactivity, solubility and toxicity.

Bioavailability: The fraction of a substance in the environment that is accessible for uptake by organisms and can exert biological effects.

References

1. Ocean acidification increases cadmium accumulation in marine bivalves: a potential threat to seafood safety. Scientific Reports (2016).
2. Ocean acidification increases copper toxicity differentially in two key marine invertebrates with distinct acid-base responses. Scientific Reports (2016).
3. Effect of Ocean Acidification on the Speciation of Metals in Seawater. Oceanography (2009).
4. The Combined Effects of Ocean Acidification and Heavy Metals on Marine Organisms: A Meta-Analysis. Frontiers in Marine Science (2021).
5. Emergent interactive effects of climate change and contaminants in coastal and ocean ecosystems. Frontiers in Marine Science (2022).
6. Evaluation of the Effect of Local Water Chemistry on Trace Metal Accumulation in Puget Sound Shellfish Shows That Concentration Varies With Species, Size, and Location. Frontiers in Marine Science (2021).