A Mathematical Model of Microbially-Induced Convection in Sea Ice

Abstract. Through its role as a an interface between ocean and atmosphere, sea ice is important both physically and biologically. We propose here that the resident microbial community can influence the structure of sea ice, particularly near its ocean interface, by effectively lowering the local freezing point via an osmolytic mechanism. The lower freezing point can enhance fluid flow, linking a bottom, convective ice layer with the underlying ocean, resulting in improved nutrient uptake and byproduct removal. A mathematical model based on a previously suggested abiotic one dimensional simplification of mushy ice fluid dynamics is used to illustrate, and supporting measurements of freezing point depression by lab grown sea ice-associated organisms are provided.