How does the runoff of nutrients affect the growth of phytoplankton and epiphytes? How do these algal blooms influence the growth of seagrasses?
Nutrient enrichment is suspected as a direct cause of increased epiphytic algae on seagrass blades. Although epiphytes provide food for invertebrate communities, too much epiphytic coverage inhibits light availability for seagrass photosynthesis. Studies show that these nutrients have also increased the growth of phytoplankton. Because of the increased algae blooms, the water in which seagrass lives has become much more turbid. This reduces the amount of sunlight available, which is vital for seagrass growth. A study conducted in Hillsborough Bay showed that phytoplankton productivity increased because of nutrient enrichment from domestic sewage and phosphate mining discharges. The phytoplankton contributed to the problem of turbidity in such a way that seagrasses existed only in small thin patches.
