Molybdenum as a Factor Limiting Primary Productivity in Castle Lake, California.

A trace-element deficiency is evident from carbon-14 bioassays of Castle Lake's natural phytoplankton populations. Increase in photosynthetic rates with the addition of molybdic acid or sodium molybdate has been demonstrated throughout the year. It is likely that other trace elements may also be found to be limiting factors in lakes having a limited watershed.