Copper Speciation in Seawater: Structure and Function of Novel Chelators

Cornell Univ - State: Awds Made Prior May 2010, Ithaca NY

Investigators

Abstract

ABSTRACT OCE-0451781 Little is known about the chemical composition of the ligands that reduce free copper (Cu) ion concentrations from toxic to nutritive levels or what their source is. Recently, a scientist from Cornell University identified two novel thiols exuded by Emiliania huxleyi in response to Cu. Using laboratory based continuous cultures, the principal investigator proposes to determine how environmental conditions influence the composition of the ligands exuded by E. huxleyi and assess the biochemical role of the recently identified novel thiols. In addition, the chemical stability of dithiol-Cu(I) complexes and the mechanisms that form thiol-Cu(I) complexes will be established. Stable Cu isotopes will be used to evaluate how thiol ligands alter the bioavailability of Cu and whether complexes can be taken up by algae when Cu concentrations are low. Two distinct mass spectroscopy techniques will be used to identify additional ligands synthesized and exuded by Synechococcus and Amphidinium carterae in response to Cu. A fluorescent probe and high pressure liquid chromatography coupled to ion trap mass spectroscopy will be used to determine the structure of thiol ligands. The second analytical approach, inductively coupled plasma mass spectroscopy detection in parallel with a quadropole mass spectrometer downstream of a high pressure liquid chromatography, will characterize ligands regardless of the functional group responsible for Cu chelation. As regards broader impacts, this project is a cutting edge metal speciation study utilizing two relatively new mass spectroscopy approaches to further our knowledge of the biogeochemistry of copper. The PI will continue her participation in Curie Academy, a program aimed at high school girls to introduce the excitement of science and engineering, as well as in "Chemistry Day", an event held at a local mall aimed at exposing local children in K-12 to the field of chemical oceanography.