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. Seagrass provide oxygen, nutrients, anchorage, food, habitat, cover, and places for attachment.





Seagrass Cover


Bay System Seagrass Meadow Area Area of Bay Bottom Percent 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


  1. 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.
  2. 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.
  3. Examine the rankings. Do you see any relationships between the measurements provided and seagrass coverage? How about location north and south? If so, explain.

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