4th UF Water Institute Symposium Abstract

Submitter's Name Thomas Arnold
Session Name Poster Session: Impact of changing drivers on water resources
Poster Number 44
Author(s) Thomas Arnold,  University of Florida (Presenting Author)
  William Kenney,  University of Florida
  Evaluating shifts and sources of organic matter input to Lake Harris, Florida, USA.
  A recent study of Lake Harris (Kenney et al. 2010) used multiple geochemical proxies to identify a pre-settlement shift in primary producer community structure (PPCS) that was not associated with significant changes in sediment phosphorus composition. This shift in PPCS may have been associated with the onset of a wetter climate at the end of the Little Ice Age, ca. 1850. Geochemical analysis of the complete sediment record revealed that the recent shift in PPCS was unique in the history of the lake. To further elucidate shifts in PPCS, molecular and isotopic analyses of lipid biomarkers will be performed on the sediment sampled from the Lake Harris core. Lipid biomarkers that are indicative of particular vegetative communities (algal, cyanobacteria, and higher plants) will be used to assess changes in the relative contributions of allochthonous and autochthonous organic matter to the lake. The carbon isotope composition (δ13C) of individual plant biomarkers will be compared to the δ13C signature of the total sedimentary organic matter to further evaluate shifts in primary production throughout time.