1. Texas Ecoregions
7.8B: I can analyze the effects of weathering, erosion, and deposition on the environment in ecoregions of Texas

2. What Is An Ecoregion?
Ecoregion - a major ecosystem (smaller than a biome) with distinct geography, plants and animals, and receives uniform solar radiation and moisture
In the natural world, environments are characterized by:
Types of soil
Precipitation
Temperature
Land features
Vegetation
Animal wildlife

3. Mechanical/Physical Weathering
Mechanical or physical weathering is the process by which rock is broken down into smaller pieces by physical changes.

5. Mechanical/Physical Weathering
Some ways that rock can be broken down physically include:
Temperature Change – a rise in temperature will cause a rock to expand and a decrease in temperature will cause a rock to contract. Repeated changes in temperatures will cause the rock to crumble.
Abrasion – rock can be broken down by the action of other rocks; wind, water, glaciers, and gravity carry different sized pieces of sediment that can strike a rock causing it to break apart or wear down.
Animal Action – animals digging and burrowing can cause rock to break apart of become more exposed to other agents of weathering.
Plant Growth – roots of plants break apart rock as they grow and increase in size

6. Chemical Weathering
The breakdown of rocks by chemical reactions. Occurs more often in locations with high precipitation rates and high temperatures.
Oxidation – when materials in rock react with the oxygen in air or water causing a change. (ex. rusting and corchemical rosion).

7. Acid Rain – Some acids form naturally when chemical in the atmosphere combine with water in the air and cause acid precipitation. The acid rain weathers rock and changes its composition.
Acids from organisms - Lichen and mosses produce weak acids that break down the rock that they grow on.

8. Erosion
Erosion is the process by which weathered rock pieces are carried away.
During the process of erosion, sediment is removed from one area on Earth’s surface and carried to another.
Erosion is reduced by vegetation (plant life).
Agents of erosion include the following
– Moving water – Wind – Glaciers – Gravity

9. Deposition Deposition the placement of sediment
after being carried from place of origin
Some formations due to deposition are…
Floodplains – the sediment that is deposited after flood waters recede
Deltas – when a river flows into an ocean, the river slows down and deposits the sediment it was carrying
Alluvial fans – when a stream flows down hill onto a flat land surface, the sediment forms a fan-shaped deposit –
Beaches – when water moves down hill and meets a nonflowing body of water, it slows down and deposits the sediment. Waves also help shape the beach.
Dunes – when wind carrying sand is blocked by an upward slope, it slows down and deposits the sediment, causing the sand to pile up

12. What is the topography of the ecosystems?

13. Which ecoregions have the most precipitation
Which ecoregions have the most precipitation? What effect could that have on vegetation? On erosion and deposition?

14. 1. Piney Woods
Due to abundant precipitation and abundant vegetation that holds the soil in place, there is very little erosion.
Thick vegetation near rivers inhibits/prevents river erosion.

15. 2. Oak Wood & Prairies
Has gently rolling hills and lightly wooded plains.
moderate rainfall that helps shape the land.
Trees and grasses prevent large amounts of soil erosion due to water and wind.

16. 3. Blackland Prairie nutrient-rich soils
receive good amounts of rainfall through the year.
If the land is clear-cut of natural vegetation for construction, nutrients can easily be eroded.
If the land is used for farming and it is not managed well, nutrients will be quickly used up.

17. 4. Gulf Coast Prairies/Marshes
Wave action, a cause of weathering, erosion and deposition, is constant along the Texas Coastline.
Sediments are weathered and eroded along beaches and carried out into the ocean to form barrier islands (like Galveston).
Can have extensive flooding from storms and hurricanes
Estuaries (salt and fresh water meet)
HOUSTON is in this ecoregion!

19. 5. Coastal Sand Plain Soil in the region is primarily sand-based.
If there isn’t enough vegetation to keep the soil in place, rainfall received can cause severe erosion.
Catastrophic events such as hurricanes can increase wave erosion and deposition.

20. 6. South texas Brush Country
The area is known as “Brush Country” due to the shorter trees and many shrubs.
Overgrazing of the land has allowed nutrient-rich topsoil to erode way.
Runs from edges of the Hill Country to the Lower Rio Grande Valley
Mostly dry and covered with grasses and thorny brush prickly pear cacti

21. 7. Edwards Plateau
Erosion has left most of the region with very shallow soils (less than 10 inches) lined with limestone rock layers.
High amounts of rain in a short amount of time can cause flash flooding.
Rainwater mixes with carbon dioxide in the atmosphere and soils to form carbonic acid, which acts to dissolve away limestone.

23. 8. Llano Uplift
The soil is not as prone to flooding because it allows water to infiltrate very easily  Underground lakes in the Edward’s Aquifer area
The region is described as rough, hilly terrain.
The weathering has exposed the granite dome underneath  Enchanted Rock (Austin area)
Plant roots causes mechanical weathering in this region

24. 9. Rolling Plains
Soils in this area are most fertile and sought after for crop production.
Periods of drought and then sudden increase in rainfall causes large amounts of erosion and deplete the soil of nutrients.

25. 10. High Plains “Texas Panhandle”- is on a high, flat plateau.
Largest and most completely flat areas of its size in the world! Mostly flat and grassy, treeless
The region extends to the Palo Duro Canyon-the nation’s 2nd largest canyon.
Palo Duro Canyon was formed by water erosion from the Red River.
The water deepens the canyon by moving sediment downstream.
Wind and water erosion gradually widen the canyon over long periods of time.

27. 11. Trans Pecos
Desert portion” of Texas. Hot dry desert that is cool at night
bedrock has a large amount of calcium.
Home of the tallest mountain in Texas, The Guadalupe Peak. (8,749 feet).
Pines and Oaks dominate the tree species.
Soils are shallow and rocky.
Soils in the canyon bottoms and valleys are deeper as a result of deposition.

28. Trans Pecos

30. 12. Marine environment
Marine topography refers to the shape the land along coastlines, but they occur also in significant ways underwater.
The effectiveness of marine habitats is partially defined by these shapes, including the way they interact with and shape ocean currents.
Marine topographies include coastal and oceanic landforms ranging from coastal estuaries (where freshwater and saltwater meet) and shorelines to coral reefs.