Properties and sources of ice nucleating substances and ice recrystallization inhibition substances from high latitudes ...

• Main Author: Xi, Yu
• Format: Text
• Language: English
• Published: University of British Columbia 2022
• Subjects: Antarc*; Antarctic; McMurdo Sound; Ross Sea; Sea ice
• Online Access: https://dx.doi.org/10.14288/1.0407332; https://doi.library.ubc.ca/10.14288/1.0407332

Ice nucleating substances (INSs) are substances capable of initiating ice formation. Atmospheric INSs can affect the formations and properties of mixed-phase clouds and ice clouds and thus influence the Earth’s climate system. Despite the importance of INSs, our understanding of the sources, concentrations, and properties of INSs is still limited. This dissertation focuses on INSs from high latitude regions. Sea-ice diatom exudates collected from two locations in the Antarctic caused freezing at temperatures from -17 to -22 °C. The results suggested that sea-ice diatom exudates can act as INSs once emitted to the atmosphere. According to a heat assay and a filter assay, possible candidates for the INSs in the exudate samples from the Ross Sea and the McMurdo Sound are polysaccharide-containing nanogels and protein-containing nanogels, respectively. Cyanobacteria mat exudates from the Antarctic caused freezing at temperatures from -5 to -13 °C, with possible INS candidates being aggregates containing ...