Fluorine is not considered to be an essential nutrient, but the importance of fluorides for preventing tooth decay is well-recognized, although the effect is predominantly topical.
A large phytoplankton bloom was triggered, however this bloom did not contain diatoms because the fertilized location was already depleted in silicic acid, an essential nutrient for diatom growth.
Not usually considered an essential nutrient in dogs, taurine is plentiful in most whole meats whether raw or cooked, but is reduced in extruded diets.