Down Under Grasslands


The student will be able to calculate percentages and rank data relating to seagrass beds in Texas estuaries.


Seagrasses are plants that root, pollinate, and spend their entire lives submerged in shallow waters. Turtlegrass is a favorite of, you guessed it--sea turtles, and south Texas shoalgrass meadows feed nearly 350,000 redhead ducks--half the world's population. Seagrasses provide oxygen, nutrients, anchorage, food, habitat, cover, and places for attachment.


  • estuary
  • percent
  • seagrass

Seagrass Cover

Bay SystemSeagrass Meadow AreaArea of Bay BottomPercent Seagrass
 Galveston Bay  _____391  _____143,153    ___/___
 Matagora Bay  _____1096  _____101,368   ___/___
 San Antonio Bay  _____2743  _____54,335   ___/___
 Aransas Bay  _____2455  _____47, 267   ___/___
 Corpus Christi Bay  _____5249  _____43,550   ___/___
 upper Laguna Madre  _____24,900  _____33,100   ___/___
 lower Laguna Madre   _____48,200  _____68,400   ___/___

*all measurements are hectares


The Texas bay systems above are listed in order from north to south. Use the measurements provided to calculate the percent seagrass coverage in each bay.
Rank the measurements in each category. Number one through seven from largest to smallest. Record the rankings in the blanks to the left of each measurement, including percent seagrass coverage.
Examine the rankings. Do you see any relationships between the measurements provided and seagrass coverage? How about location north and south? If so, explain.