Abstract

Understanding the influence of temperature on the diffusion coefficient of crude oil in water is crucial for assessing environmental impact of oil spills, particularly under conditions of climate change. Oil spills can have catastrophic consequences on ecosystems, harming or killing fish, dolphins, whales and other marine animals, as well as damaging delicate habitats such as coral reefs and mangroves. This study compares the predictions of an empirical model with those of the fundamental Stokes-Einstein equation for the temperature dependence of crude oil diffusion. The diffusion coefficient was calculated using both an empirical model and the Stokes-Einstein model for temperatures ranging from 1oC to 100oC using both models. Results indicate that the Stokes-Einstein equation predicts higher diffusivity at lower temperatures, whereas the empirical model predicts significantly greater diffusivity at higher temperatures. At elevated temperatures, the empirical model estimates diffusion rates nearly twice as high as those predicted by the Stokes-Einstein model. These results are critical for predicting the rapidity of spread of oil spills with global warming. Specifically, during non-steady state diffusion, the time required for oil to travel a specific distance is inversely related to the dif fusion coefficient. This means that as temperature increases and diffusivity rises, oil spreads more rapidly and in turn reduces the time to contaminate swaths of ocean, a problem worsened by warming ocean temperatures. Given the limitations of current models and the fact that the empirical model was developed using distilled water, future research will require more experimental data at higher temperatures under conditions that mimic actual seawater. This can enable the development of more accurate diffusion models and improve predictive tools for managing the impact of oil spills.

DOI: doi.org/10.63721/25JGEAS0114

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