POPs, including chemicals like DDT, polychlorinated biphenyls (PCBs), and per- and polyfluoroalkyl substances (PFAS), are notorious for their environmental longevity and toxicity. Even decades after many have been banned under the UN’s Stockholm Convention, their stability and fat-solubility ensure they persist in marine sediments, water columns, and the tissues of organisms. Now, climate-driven changes are disturbing these chemical reservoirs in unpredictable ways.
The melting of the Arctic and Antarctic cryospheres, intensified atmospheric transport, and remobilization of sediments are among the key processes identified as enhancing POP dispersion into marine ecosystems. These changes could intensify bioaccumulation in fish, seabirds, and marine mammals, with unknown long-term consequences for food webs and ecosystem resilience.
The review examined 254 studies globally, finding that research has been heavily concentrated in Arctic environments, with significant data gaps in the Southern Hemisphere and tropical regions. The authors highlight the compounded risks posed by multi-stressor scenarios: warming temperatures, ocean acidification, deoxygenation, and chemical pollution may combine to create “emergent effects” not previously observed.
For instance, remobilization of POPs from melting sea ice has been detected in the Canadian Arctic, and a measurable increase of perfluorinated compounds has been reported in Arctic sediment cores. In Antarctic coastal lakes, melting glaciers were found to contribute significantly higher DDT levels compared to non-glacial lakes.
In temperate regions like coastal Australia, flooding has been linked to higher POP levels in local dolphin populations, indicating that extreme weather events could trigger chemical releases far beyond the poles.
The effects of increased POP exposure are species- and context-specific, according to the review. Some marine species may experience greater pollutant uptake with warming temperatures, while others show mixed responses due to complex interactions between bioaccumulation and detoxification processes.
Notably, experiments on fish and amphibians revealed that elevated temperatures can both increase uptake of PCBs and reduce biological half-lives of some POPs, complicating predictions for long-term accumulation trends. Coral species like Stylophora pistillata experienced heightened oxidative stress when exposed to PFOS under warmer conditions, indicating that reef ecosystems are particularly vulnerable.
Moreover, the review’s conceptual model suggests that indirect climate impacts—such as increased storm surge, flooding, and wildfires—could act as unexpected triggers for POP remobilization across global marine environments.
The study authors emphasize the urgent need for expanded monitoring and predictive modeling tools. Current assessments are largely restricted to legacy POPs and limited regions, leaving many newer chemicals like PFAS poorly characterized.
Given the interconnected nature of climate and chemical stressors, the researchers recommend that multi-stressor ecological risk assessment frameworks become standard in evaluating marine pollution threats.
As marine ecosystems stand at this critical intersection of global warming and chemical pollution, understanding and mitigating these dual pressures will be pivotal for protecting biodiversity and the health of human populations reliant on ocean resources.
