The type of material was one control of the persistence of commercial drinking straws in the coastal ocean. Each straw was visibly biofouled during the experiment (Figure ). The CDA, PHA, and paper straws reduced in mass by 25-50% within 16 weeks (Figure ). The gain in mass loss for the CDA straw at the four week time point was due to the straw's leaching of triacetin plasticizer. There were no measurable mass losses for the PLA and PP straws, affirming that these materials persist over many years in the marine environment. Our results reiterate that items designed only for industrial composting (i.e., PLA) are likely persistent in coastal marine conditions. In this study, we assume that mass loss of an article equates to biodegradation of the polymer to CO2. This assumption is reasonable for CDA, PHA, and paper materials because it is wellestablished that these materials biodegrade to CO2 in the coastal ocean. Moreover, our previous research on CDA showed that mass loss rates were comparable to respiration rates and, consistent with the absence of waves and abrasives (e.g., sand) in our study system, no mass loss was detected in sterilized controls. Additionally, because biodegradation is a surface driven process, if any mass loss were attributed to physical disintegration (fragmentation), this would only increase the fragments' surface area and thus mass loss (Equation ) and respiration rates.