Scientists can estimate the input of nitrates
to the Gulf from the Mississippi River Basin, but once
the nitrates are mixed in the ocean, are the changes
in nitrate concentrations observable? The map below
shows annual average nitrate concentrations at the surface.
Concentration is measured in micro-molarity (µM)
or thousandths of a mole of nitrate per liter of seawater.
! Click the buttons to see nitrate concentration
for each season. Examine the maps and the color code
to interpret how nitrate levels changed through the
year. Focus on changes in the Gulf of Mexico.