Date of Award
Spring 5-19-2026
Document Type
Thesis: Open Access
Degree Name
MS Marine Science
Department
Environmental and Ocean Sciences
Committee Chair
Jennifer Prairie
Committee Member
Nathalie Reyns
Committee Member
Michel Boudrias
Abstract
The primary method for carbon sequestration in the ocean is the sinking of marine snow aggregates, coagulated particles of phytoplankton cells and detritus, which sink up to 100 times faster than individual phytoplankton cells. These aggregates are not homogenously distributed in the ocean, but rather are know to form distinct layers often associated with sharp density gradients. It has been suggested that these layers form through delayed setting, the temporary decrease in aggregate settling velocity upon reaching a density interface, but the mechanistic relationship between the two has never been investigated in a laboratory setting. The goal of this experimental study was to determine how density gradient strength affects the delayed settling behavior of a single marine snow aggregate, and subsequently the properties of the marine snow layer that forms. Aggregates were exposed to density gradients that spanned three different vertical distances, and aggregate settling and layer properties were quantified through image analysis. This study provides a mechanistic understanding of how density gradients of different strengths control the formation of marine snow layers, which in turn has implications for marine carbon cycling since these layers are hot spots for microbial degradation and zooplankton foraging, and can thus decrease carbon flux.
Copyright
Copyright held by the author
Digital USD Citation
Drozda, Emma J., "The Effect of Density Gradient Strength on the Settling of Marine Snow Aggregates and the Formation of Marine Snow Layers" (2026). Theses. 95.
https://digital.sandiego.edu/theses/95