Document Type

Master's Thesis

Degree Name

Master of Science (M.S.)


Moss Landing Marine Laboratories


omoic acid (DA) is a neurotoxic amino acid produced by several members of the diatom genus Pseudo-nitzschia. Trophic transfer of DA has been implicated in the deaths of 100's of marine birds and mammals along the central California coast. Although the physiological role of DA has not been well established, evidence herein strongly suggests that DA functions to buffer dissolved inorganic copper (Cu'). Evaluating the homeostatic function of DA with respect to copper metabolism gave rise to three major findings: 1) DA binds Cu' with an avidity comparable to the L2 ligand class KcondCuDA=1.0x10¹² (pH 8.2, I=0.02), 2) P. multiseries is tolerant to wide fluctuations [Cu'] loadings (pCutotal 10.8-3.26) because of strain-specific modulation of free amino acids pools (FAA), with up to a 10-fold increase in DA accumulation (31fg DA/cell) in response to elevated [Cu'], 3) Cu' and total DA concentrations were highly correlated during a field survey spanning 97 days along a 3 kilometer transect in Monterey Bay, CA (r>=0.79, n=3, a=0.01). Cumulatively, these results establish DA's significant influence on Cu homeostasis in Pseudo-nitzschia species.


Thesis (M.S.) Earth Systems Science & Policy Institute. Moss Landing Marine Laboratories