<html aria-label="message body"><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>Dear Soft Matter & Complex Systems Colleagues and Friends,</div><div><br></div><div>On Friday 22 May 2026 at 9:30 AM at the UW Faculty of Physics (Pasteura 5, Warsaw; room 1.40) we are hosting a seminar, during which</div><div><br></div><div><b>Jan Turczynowicz</b> (FUW)</div><div><br></div><div>will give a talk</div><div><br></div><div><b>Measurements of biological carbon sequestration in the oceans</b></div><div><br></div><div><b>Abstract</b></div><div>The oceans capture a significant portion of human-made CO2. In the upper 100 meters (the euphotic zone), phytoplankton convert this dissolved gas into organic matter, which aggregates into sinking particles known as marine snow. This process, called the biological carbon pump, is a critical mechanism for burying carbon on the seabed.
Field observations, described by the Martin curve, show that carbon flux drops rapidly with depth, with only about 10% of this material sinking past 200 meters. However, directly measuring this curve is difficult. While indirect methods using radioactive thorium isotopes are widely popular, they present significant inconsistencies. This talk will discuss the issues surrounding thorium-based estimates and present an alternative method based on oxygen distributions, which shows promising agreement with direct measurements.</div><div><br></div><div>We warmly welcome everyone to attend the talk and the Soft Matter Coffee Break after the seminar, held in room 2.63 (2nd floor).</div><div><br></div><div>Maria Ekiel-Jeżewska</div><div>Maciej Lisicki</div><div>Piotr Szymczak</div><div>Panagiotis Theodorakis</div></body></html>