Nutrient Use and Remineralization

    Cards (29)

    • Nutrients -> any element required by organisms for growth
    • some nutrients are so abundant as to never limit growth
    • in aquatic ecosystems limiting nutrients for primary producers is most often nitrogen, phosphorus, silicon, and iron
    • lipids require phosphorus
    • amino acids/proteins require nitrogen
    • nucleotides require nitrogen and phosphorus
    • primary producers use mostly inorganic nutrients
    • animals and other eukaryotic organisms use organic nutrients
    • bacteria use both inorganic and organic nutrients
    • What are the two components of nutrient use?
      uptake and assimilation
    • uptake -> process of nutrients being taken into cells from surrounding water
    • assimilation -> incorporation of nutrients into organic molecules used for growth
    • uptake can occur without assimilation
    • the rate of uptake is dependent on concentration of nutrients in water
    • rate of growth (assimilation) controlled by nutrient supply, pH, temperature, light
    • nutrient concentration inside cell is more important than outside
    • growth rate can be predicted by concentration of nutrients outside the cell
    • Explain Luxury Consumption
      some organisms can take up nutrients at high rates when exposed to high nutrient concentrations for short periods, having nutrient storage is a competitive advantage. But organisms cannot sustain growth proportional to this uptake
    • nutrient limitation -> control of growth or production by a nutrient or nutrients
    • carbon, nitrogen, and phosphorus are typically most limiting in aquatic ecosystems based on demand relative to availability, however, for photosynthetic organisms CO2 is very abundant
    • remineralization is release of inorganic nutrients by organisms
    • What are the two processes that lead to remineralization?
      decomposition of dissolved and particulate organic matter and metabolic activity within living organisms
    • how can primary producers lead to remineralization?
      cells leak and are broken releasing dissolved organic and inorganic nutrients
    • How do heterotrophs lead to remineralization?
      excrete surplus nutrients as wastes
    • for nutrients to be used there must be both uptake and assimilation
    • uptake is controlled by concentration outside of cell
    • assimilation is controlled by concentration inside the cell
    • availability of nutrients is controlled by geology and land use
    • remineralization is cycling of nutrients from organic to inorganic forms by organisms