it has been reported that in the winter months, when temperatures reach 0 °c, there is a large accumulation of round cyst-like cells that deposit themselves on the bottom of the great salt lake.  this encysting property of "dunaliella" must have been critical for its survival in the dead sea, where salt concentrations have risen to intolerable amounts, such that the organism cannot be found in the water column today. in remote sensing, however, they found that when they diluted the upper waters, dunaliella showed up; perhaps emerging from the shallow sediments where they had encysted. back when the alga was found in the water column, however, population rate monitoring revealed that "dunaliella" growth was inhibited by high concentrations of magnesium and calcium ions. "dunaliella" blooms can therefore only occur in the dead sea when the waters become sufficiently diluted by winter rains and when the limiting nutrient phosphate is available.