Dataset: Percent activity of organic fractions from diatoms that bind with radionuclide

ValidatedFinal no updates expectedDOI: 10.1575/1912/bco-dmo.764885.1Version 1 (2019-04-11)Dataset Type:experimental

Principal Investigator: Peter Santschi (Texas A&M, Galveston)

Co-Principal Investigator: Antonietta Quigg (Texas A&M, Galveston)

Co-Principal Investigator: Kathleen Schwehr (Texas A&M, Galveston)

Co-Principal Investigator: Chen Xu (Texas A&M, Galveston)

BCO-DMO Data Manager: Mathew Biddle (Woods Hole Oceanographic Institution)


Project: Biopolymers as carrier phases for selected natural radionuclides (of Th, Pa, Pb, Po, Be) in diatoms and coccolithophores (Biopolymers for radionuclides)


Abstract

Percent amount of organic fractions from diatoms that bind with radionuclide. In order to investigate the importance of biogenic silica associated biopolymers on the scavenging of radionuclides, the diatom Phaeodactylum tricornutum was incubated together with the radionuclides 234Th, 233Pa, 210Pb, and 7Be during their growth phase. Normalized affinity coefficients were determined for the radionuclides bound with different organic compound classes (i.e., proteins, total carbohydrates, uronic acid...

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Percent amount of organic fractions from diatoms that bind with radionuclide. In order to investigate the importance of biogenic silica associated biopolymers on the scavenging of radionuclides, the diatom Phaeodactylum tricornutum was incubated together with the radionuclides 234Th, 233Pa, 210Pb, and 7Be during their growth phase. Normalized affinity coefficients were determined for the radionuclides bound with different organic compound classes (i.e., proteins, total carbohydrates, uronic acids) in extracellular (nonattached and attached exopolymeric substances), intracellular (ethylene diamine tetraacetic acid and sodium dodecyl sulfate extractable), and frustule embedded biopolymeric fractions (BF). Results indicated that radionuclides were mostly concentrated in frustule BF. Among three measured organic components, Uronic acids showed the strongest affinities to all tested radionuclides. Confirmed by spectrophotometry and two-dimensional heteronuclear single quantum coherence-nuclear magnetic resonance analyses, the frustule BF were mainly composed of carboxyl-rich, aliphatic-phosphoproteins, which were likely responsible for the strong binding of many of the radionuclides. Results from this study provide evidence for selective absorption of radionuclides with different kinds of diatom-associated biopolymers acting in concert rather than as a single compound. This clearly indicates the importance of these diatom-related biopolymers, especially frustule biopolymers, in the scavenging and fractionation of radionuclides used as particle tracers in the ocean.

 


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Methods

Alvarado Quiroz, N. G., Hung, C.-C., & Santschi, P. H. (2006). Binding of thorium(IV) to carboxylate, phosphate and sulfate functional groups from marine exopolymeric substances (EPS). Marine Chemistry, 100(3-4), 337–353. doi:10.1016/j.marchem.2005.10.023
Methods

Chuang, C-Y., Santschi, P. H., Xu, C., Jiang, Y., Ho, Y., Quigg, A., Guo, L., Hatcher, P. G., Ayranov, M., & Schumann, D. (2015). Molecular level characterization of diatom‐associated biopolymers that bind 234 Th, 233 Pa, 210 Pb, and 7 Be in seawater: A case study with Phaeodactylum tricornutum. In Journal of Geophysical Research: Biogeosciences (Vol. 120, Issue 9, pp. 1858–1869). American Geophysical Union (AGU). https://doi.org/10.1002/2015jg002970
Methods

Guo, L., Santschi, P. H., Baskaran, M., & Zindler, A. (1995). Distribution of dissolved and particulate230Th and232Th in seawater from the Gulf of Mexico and off Cape Hatteras as measured by SIMS. Earth and Planetary Science Letters, 133(1-2), 117–128. doi:10.1016/0012-821x(95)00063-i
Methods

Quigley, M. S., Santschi, P. H., Hung, C.-C., Guo, L., & Honeyman, B. D. (2002). Importance of acid polysaccharides for234Th complexation to marine organic matter. Limnology and Oceanography, 47(2), 367–377. doi:10.4319/lo.2002.47.2.0367
Methods

Roberts, K. A., Xu, C., Hung, C.-C., Conte, M. H., & Santschi, P. H. (2009). Scavenging and fractionation of thorium vs. protactinium in the ocean, as determined from particle–water partitioning experiments with sediment trap material from the Gulf of Mexico and Sargasso Sea. Earth and Planetary Science Letters, 286(1-2), 131–138. doi:10.1016/j.epsl.2009.06.029