Microplastics (MPs) are increasingly detected throughout the atmosphere, raising questions about their persistence and uncertain effects on atmospheric processes, such as cloud formation. Recent studies suggest that MPs may act as ice-nucleating particles (INPs), facilitating the freezing of water at higher temperatures. Biological colonization may enhance this activity; for instance, the bacterium Pseudomonas syringae—a model organism for biological ice nucleation—is known to colonize and form biofilms on MPs. In this study, we examined the ice nucleation activity (INA) of MPs with and without colonization by P. syringae. Different strains of P. syringae, varying in their INA, were cultured on pristine and aged polystyrene (PS) and polyethylene (PE) MPs, 100 µm in diameter. All MPs studied (0.5µm to 100µm PS and 100µm PE) exhibited INA, with median freezing temperatures ranging from -21.0 °C to -23.8 °C. After aging via hydrothermal or photooxidation exposure, most MPs showed a slight but non-significant increase in the median freezing temperature. PE MPs froze at higher temperatures than PS MPs and the size of MPs did not appear to impact mean freezing temperatures. Biofilm colonization of MPs by P. syringae significantly increased median freezing temperatures by approximately 6.5 °C (p<0.0001). P. syringae was also found to be a more effective ice nucleator when colonizing the surface of MPs. These findings demonstrate that environmentally relevant MPs—those altered through aging and biological colonization—exhibit a greater propensity to act as INPs compared to pristine particles, highlighting the need for atmospheric models to account for this so far understudied interaction between MPs and biological INPs.
Publisher
University Libraries, Virginia TechCorresponding Author Name
Hosein ForoutanFiles/Folders in Dataset and Description
[Carpenter_et_al_0.5um_PS_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of both pristine and aged 0.5µm PS microspheres from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_1.0um_AmPS_assay.csv]- Contains freezing assay data pertaining to 12µL droplets of both pristine and aged 1.0 µm AmPS microspheres from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_1.0um_CaPS_assay.csv]- Contains freezing assay data pertaining to 12µL droplets of both pristine and aged 1.0 µm CaPS microspheres from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_1.0um_SuPS_assay.csv]- Contains freezing assay data pertaining to 12µL droplets of both pristine and aged 1.0 µm SuPS microspheres from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_2.0um_biotinPS_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of both pristine and aged 2.0 µm biotin coated PS microspheres from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_2.0um_streptPS_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of both pristine and aged 2.0 µm streptavidin coated PS microspheres from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_6.0um_PS_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of aged 6.0 µm PS microspheres from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_10.0um_PS_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of aged 10.0 µm PS microspheres from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_100um_PE_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of both pristine and UV aged 100 µm PE microspheres from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_100um_PS_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of both pristine and UV aged 100 µm PS microspheres from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_Pseudomonas_syringae_ICE+_PE_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of pristine PE microspheres colonized by ice+ P. syringae from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_Pseudomonas_syringae_ICE+_PEUV_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of pristine PEUV microspheres colonized by ice+ P. syringae from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_Pseudomonas_syringae_ICE+_PS_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of pristine PS microspheres colonized by ice+ P. syringae from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_Pseudomonas_syringae_ICE+_PSUV_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of UV aged PS microspheres colonized by ice+ P. syringae from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_Pseudomonas_syringae_ICEminus_PE_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of pristine PE microspheres colonized by ice- P. syringae from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_Pseudomonas_syringae_ICEminus_PEUV_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of pristine PEUV microspheres colonized by ice- P. syringae from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_Pseudomonas_syringae_ICEminus_PS_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of pristine PS microspheres colonized by ice- P. syringae from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_Pseudomonas_syringae_ICEminus_PSUV_assay.csv] - Contains freezing assay data pertaining to 12µL droplets of UV aged PS microspheres colonized by ice- P. syringae from 0 °C to -25 °C. The data includes the number of droplets frozen at each representative temperature with a sample size of 32 for each row. Rows are indicative of replicates.
[Carpenter_et_al_statistical_analysis_IGORPro9.csv] – Contains statistical data obtained from IGOR Pro 9.
