Sample Marine Lesson

Grasslands Down Under

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

Vocabulary
estuary
percent
seagrass

Background
Seagrasses are plants that root, pollinate, and spend their entire lives submerged in shallow waters. Special adaptations allow for their survival in the fluctuating conditions of coastal bays and estuaries. The estuaries in the Coastal Bend of Texas contain 40% of Texas' total seagrass acreage. Seagrasses 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	_____ _____
Matagorda Bay	_____ 1,096	_____ 101,368	_____ _____
San Antonio Bay	_____ 2,743	_____ 54,335	_____ _____
Aransas Bay	_____ 2,455	_____ 47,267	_____ _____
Corpus Christi Bay	_____ 5,249	_____ 43,550	_____ _____
Upper Laguna Madre	_____ 24,900	_____ 33,100	_____ _____
Lower Laguna Madre	_____ 48,200	_____ 68,400	_____ _____

* All measurements are in hectares.

Exercises

• 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 percent seagrass coverage? How about location north and south? If, so, explain.

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