Importance of acid polysaccharides for 234Th complexation to marine organic matter

• DOI: 10.4319/lo.2002.47.2.0367
• Publication Date: 2010-06-30T20:23:56Z
• Authors: Matthew S. Quigley; Peter H. Santschi; Chin-Chang Hung; Laodong Guo; Bruce D. Honeyman
• Keywords: 01 natural sciences; 0105 earth and related environmental sciences

In order to study the role of polysaccharides (PS) in colloidal organic matter (COM) pool for complexing 234 Th, controlled laboratory experiments were carried out determine chemical nature strong Th(IV) binding macromolecular ligands (>1 kDa). The partition coefficient Th between marine COM and solution, K c , is higher than that any known mineral sorbent. PS‐enriched fractions had highest ( ) sorbent Th. other metals, including Fe, Mn, Zn, Pb, Pu, up an magnitude bulk COM. Most importantly, log values correlated linearly with fraction carbon (ƒ PS COM, as 5 (0) × 10 2.2ƒPS value ~7.9 pure end‐member was very similar obtained model acid (log ~ 8). A conditional stability constant end member 7.8 could be determined from a concentration sites (with pKa <=3) 1.3 mmol g −1 Through novel use gradient gel electrophoresis (including two‐dimensional polyacrylamide electrophoresis), ligand shown ~13 kDa size have acidic functional groups. We propose observed variability OC: ratios suspended, sinking ocean might caused by content.