Temperature Controls the Lifetimes and Microbial Communities Degrading Cellulose Diacetate in the Coastal Ocean.

Cellulose diacetate (CDA), a biobased material widely used in consumer products, is biodegradable in the coastal ocean. However, the effect of water temperature on the degradation rates is unknown, limiting projections of lifetime across space and time. Here, we incubated CDA-based materials (film, foam, and straw), paper straws, polyethylene (PE) films, and poly(butylene adipate terephthalate) (PBAT) straws for 28 weeks at 10 and 20 °C in continuous-flow seawater mesocosms. The relative mass loss of the CDA film, foam, and straw increased by 20-25% from 10 to 20 °C, and their degradation rates increased by 1.8-3.1-fold. Accordingly, model predictions of CDA-based article lifetimes in North American coastal waters were highly sensitive to differences in water temperature across latitude and seasonality. Paper straws also showed a notable temperature dependence, with degradation rates increasing 1.7-fold from 10 to 20 °C. PE films and PBAT straws showed no measurable degradation at either temperature, highlighting their persistence in the ocean. Microbial communities implicated in CDA biodegradation were influenced by the material type, temperature, and incubation time. Differential abundance analysis revealed that ∼93% (29/31) of the highly responsive microbial taxa implicated in the degradation of CDA were unique at 10 and 20 °C. These findings indicate that water temperature governs the lifetime of biodegradable materials, supporting its inclusion as a primary variable in experimental frameworks moving forward.