SAVANNAH — How much of a nutrient load is too much for Georgia’s coastal rivers and estuaries? A research team from University of Georgia Skidaway Institute of Oceanography is helping Georgia’s Environmental Protection Division answer that question. Its primary focus is on the estuary of the Ogeechee River.

The nutrients are chemicals like nitrates and phosphates typically introduced into the rivers by agricultural runoff, stormwater or sewage effluents, and the natural decay of organic matter in the river. When present in high concentrations, the nutrients act as fertilizer, promoting excessive growth of marine plants, especially microscopic marine plants called phytoplankton.

Elsewhere on the East Coast, excessive nutrients in estuaries have been linked to toxic algal blooms that can cause fish kills or shellfish closures. These are not presently known to be significant problems in Georgia’s waters.

“The Georgia EPD wants to know how much nitrogen is coming down the river and whether it has any consequences when it gets to the estuary,” Skidaway scientist William Savidge said.

“There is not any current and systematic information on nutrient conditions in most of the estuaries,” he said, “nor is there much information on the consequences of nutrient availability in the estuaries, and it’s those consequences that are the most important.”

Savidge expects to report the team’s findings to Georgia EPD by midsummer.