B-vitamins and trace metals in the Pacific Ocean: ambient distribution and biological impacts

2012-11-07B-vitamins and trace metals have been implicated as important controllers of phytoplankton abundance and composition in the marine environment. In order to further establish the distribution and biological importance of dissolved B-vitamin in the Pacific Ocean, I determined the environmental concentrations of B-vitamins, the vitamin B12-dependent amino acid methionine, and the B12-precursor cobalt in the Eastern Tropical Pacific (ETSP) and the subtropical North Pacific. The environmental relevance of some toxic trace metals was also established in the coastal ocean off Los Angeles, CA. The field data was complemented with targeted laboratory and field manipulation experiments to assist in the interpretation of environmental distributions. In the ETSP, I collected and analyzed depth-profile measurements of B12, methionine, B7, B6, and cobalt at 6 stations with environmental conditions ranging from nutrient rich coastal stations to oligotrophic open ocean stations. Vitamin B12 and methionine showed similar geographical distributions suggesting a potential control of vitamin B12 on the synthesis of the amino acid likely due to B12-dependent methionine synthase. Despite low cobalt levels in the ETSP (