The sinking rate and transparent exopolymer particle (TEP) production of Hemiaulus hauckii

dc.contributor.advisorVillareal, Tracy A.
dc.creatorHoppe, Kellie Sueen
dc.date.accessioned2013-11-08T21:36:25Zen
dc.date.issued2013-08en
dc.date.submittedAugust 2013en
dc.date.updated2013-11-08T21:36:26Zen
dc.descriptiontexten
dc.description.abstractDiatom-diazotroph associations contribute extensively to vertical flux in the modern ocean, and are linked to extensive sedimentary layers in the paleo-record formed either by rapidly sinking aggregates or more slowly sinking cells and chains. Although diatom sinking rates have been extensively studied, the sinking rates of these diatom symbioses are poorly documented. The effect of silicate and phosphate limitation on the sinking rate of Hemiaulus hauckii and its symbiont Richelia intracellularis were determined in semi-continuous cultures using a SETCOL. TEP (transparent exopolymer particle) was measured concurrently for linkages to aggregate formation. Although cells occurred in chains of 1-20 cells long, aggregate formation did not occur in semi-continuous cultures. There was no significant effect of P or Si limitation on sinking rates compared to controls. Although H. hauckii possess a symbiont that lacks gas vesicles, sinking rates (0.04-0.72 m/day) were within the range predicted by size-rate relationships. A portion of each H. hauckii experimental measurement ascended as well with significant differences found between the lowered P 80% exchange and the lowered Si with 80% exchange (p=0.05) and between the lowered Si with 80% exchange and the Si control batch culture (p=0.039). TEP production did not change significantly between treatments. However, a fraction of TEP in each population was positively buoyant as well, with ascent rates between 0.32-0.49 m/day. This study confirms an earlier report of positive buoyancy in TEP as well as noting that a significant fraction of the Hemiaulus symbiosis can be ascending within the population.en
dc.description.departmentMarine Scienceen
dc.format.mimetypeapplication/pdfen
dc.identifier.urihttp://hdl.handle.net/2152/22090en
dc.language.isoen_USen
dc.subjectSinking ratesen
dc.subjectTEPen
dc.subjectTransparent exopolymer particleen
dc.subjectHemiaulus hauckiien
dc.subjectDDAen
dc.subjectSETCOLen
dc.titleThe sinking rate and transparent exopolymer particle (TEP) production of Hemiaulus hauckiien
thesis.degree.departmentMarine Scienceen
thesis.degree.disciplineMarine Scienceen
thesis.degree.grantorThe University of Texas at Austinen
thesis.degree.levelMastersen
thesis.degree.nameMaster of Science in Marine Scienceen
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