What makes the San Francisco Bay different from other estuaries that are plagued by phytoplankton blooms?
A. – In many estuaries that are surrounded by urban and agricultural areas, such as the Chesapeake Bay and San Francisco Bay, the level of nutrients can be artificially high due to run-off from suburban lawns and gardens, agricultural fields and other sources and due to wastewater discharges. This can result in rapid phytoplankton growth. Very large, poorly controlled phytoplankton blooms, such as those that occur in the Chesapeake Bay, can result in oxygen deficits in the bay’s water as the algae die. Although San Francisco Bay has high nutrient levels, it is also a very turbid system because there is lots of sediment in the water. The high turbidity limits the amount of light penetrating San Francisco Bay’s water. Therefore, the phytoplankton growth rate is limited by its ability to get sufficient light during most periods of the year and blooms are usually short lived and not very large.
