Settling velocity of atmospheric particles in seawater: Based on hydrostatic sedimentation method using video imaging techniques

Shuo Wang; Huiwang Gao; Shijie Jia; Mingliang Gu; Feng Shi; Xiaohong Yao

doi:10.1016/j.marpolbul.2024.116472

Settling velocity of atmospheric particles in seawater: Based on hydrostatic sedimentation method using video imaging techniques

Mar Pollut Bull. 2024 May 9:203:116472. doi: 10.1016/j.marpolbul.2024.116472. Online ahead of print.

Authors

Shuo Wang¹, Huiwang Gao², Shijie Jia¹, Mingliang Gu¹, Feng Shi¹, Xiaohong Yao³

Affiliations

¹ Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China.
² Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266071, China. Electronic address: hwgao@ouc.edu.cn.
³ Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266071, China.

PMID: 38728955
DOI: 10.1016/j.marpolbul.2024.116472

Abstract

When atmospheric particles deposit to the ocean, their settling velocities and residence times associated are critical for their effects on oceanic ecosystems. We developed a hydrostatic sedimentation method using video imaging techniques to track particles of 5-20 μm in diameter falling into seawater and determine the particle settling velocities in relation to their diameter, shape, organic matter contained, and seawater salinity. The measured settling velocities varied from 0.025 to 0.41 mm/s. Irregular particle shape and organic matter contained in particles also, however, reduced the values. The settling velocities were decelerated by the dissolution process of particle in seawater. Combined with the experimental results, a formula for calculating the settling velocity formulae for atmospheric particles was estimated. Using this equation, the residence time of particles is estimated to be less than one month in continental shelf sea and more than 100 days in the oceans.

Keywords: Atmospheric particle; Organic matter; Predictive formula; Settling velocity; Video imaging technique.