Nutrients: are not "food," but are more like vitamins and minerals (fertilizer) essential to life functions.
• Aids in the production of food (primary production).
• Nutrients are essential to support photosynthesis—the process that provides sugars (energy) to support all other life processes.
• There are many more intermediate processes requiring nutrients to produce other complex organic compounds (proteins, carbohydrates, fats, etc).
Sources of Nutrients: Upwelling and continental weathering & erosion
Primary nutrients = nitrates and phosphates
Secondary = minerals: calcium, iron, zinc, sodium, and many others.