<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div style="font-family: HelveticaNeue;"><font face="HelveticaNeue">Dear Soft Matter & Complex Systems Colleagues and Friends,</font></div><div><div style="font-family: HelveticaNeue;"><font face="HelveticaNeue"><br></font></div><div style="font-family: HelveticaNeue;"><font face="HelveticaNeue">On Friday 28 March 2025 at 9:30 AM at the UW Faculty of Physics (Pasteura 5, Warsaw; room 1.40) we are hosting a seminar during which </font></div><div style="font-family: HelveticaNeue;"><font face="HelveticaNeue"><br></font></div><div style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal; min-height: 14px;"><font face="HelveticaNeue"><b>Jan Turczynowicz</b></font><font face="HelveticaNeue"><b> </b></font><font face="HelveticaNeue">(</font><font face="HelveticaNeue">IFT UW)</font></div><div style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal; min-height: 14px;"><font face="HelveticaNeue"><br></font></div><div style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue">will give a talk</font></div><div style="margin: 0px; font-stretch: normal; line-height: normal; min-height: 14px;"><div><h2 style="margin: 6px 0px 12px; padding: 0px;"><font face="HelveticaNeue"><span style="font-size: 12px;">Encounter rate in marine snow dynamics</span></font></h2><h2 style="font-family: HelveticaNeue; margin: 6px 0px 12px; padding: 0px;"><b style="caret-color: rgb(68, 68, 68);"><font face="HelveticaNeue" style="font-size: 12px;">Abstract</font></b></h2></div><div style="font-family: HelveticaNeue;">Oceans are vital carbon sinks, absorbing approximately 30% of anthropogenic carbon emissions. A portion of this carbon settles to the seafloor, reducing its presence in the short-term global cycle. The primary drivers of this vertical transport are sinking aggregates of dead phytoplankton, known as marine snow. To predict sedimentation dynamics, it is essential to understand encounters between sinking particles. Collisions between these particles promote aggregation, increasing their sedimentation velocity, while interactions with free-floating bacteria enhance dissolution, potentially slowing their descent. Models for encounter rates involve two dominant mechanisms of particle interception: advection and diffusion. The relative importance of these mechanisms depends on the sizes of the colliding particles. However, many existing studies either neglect one of these processes or simply superimpose them, raising concerns about their accuracy. Here, we present a systematic approach to modeling collision rates as a function of particle size and Peclet number.</div><div style="font-family: HelveticaNeue;"><br></div></div><div style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue">We warmly welcome everyone to attend the talk and the Soft Matter Coffee Break after the seminar, held in room 2.63 (2nd floor).</font></div></div><div style="font-family: HelveticaNeue;"><font face="HelveticaNeue"><br></font></div><div style="font-family: HelveticaNeue;"><div dir="auto" style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div style="margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue">Maria Ekiel-Jeżewska</font></div><div style="margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue">Maciej Lisicki</font></div><div style="margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue">Piotr Szymczak</font></div><div style="margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue">Panagiotis Theodorakis</font></div></div></div></body></html>