Exploring Galveston Bay: Factors Affecting Life

1. Are you ready for the map quiz?

2. Galveston Bay is an Estuary • Freshwater inflows from rivers and bayous meet saltwater from the Gulf of Mexico • Fresh + Salt = Brackish water

3. Galveston – we’re #3!

4. Today: What factors affect life in the Bay? Why are certain organisms found in certain places, but not others?

5. When you see the pattern, suggest another idea • List 2: • Brown shrimp • Oysters • Chord grass • Dolphin • Blue crab • Red drum • List 1: • Dissolved Oxygen • Tides • Wind speed and direction • Salinity • Water depth

6. Salinity is a critical abiotic factor • Freshwater inflows from rivers and bayous meet saltwater from the Gulf of Mexico • Fresh + Salt = Brackish water

7. Add to your map! • Trinity River – 54% inflow • San Jacinto River – 28% inflow • Add these numbers to your map! • On your map, add shading: more bluenear mouth of rivers and bayous, • More yellow at mouth of Bay

8. Tides affect the Bay too! • Tides are caused by the moon. • Two high tides and two low tides each day. • Tides are most dramatic closer to the ocean. • On your map, mark a point where there would be most dramatic tides (TIDES!!!) and least dramatic tides (tides) and (no tides)

9. New page interactive notebook • Title: Abiotic Factors in an Estuary • Date: check the board!

10. Copy this on the right side: • Important abiotic factors in Galveston Bay • Dissolved Oxygen • Tides • Wind speed and direction • Salinity • Water depth • Nitrates/Phosphates • pH

11. Where would you expect to find these? Add them to your map! • Juvenile blue crab - 0.0 - 0.5 ppt salt • Oysters - 0.5 - 15.0 ppt salt • Lady fish- 25.0 ppt salt • Nurse shark – 35 ppt salt • Ocean 35 ppt

12. Range of Tolerance

13. *Range of Tolerance • All organisms have a limit for each abiotic factors in their habitat. There is an upper and lower limit for how much they can tolerate.

14. What about those freshwater inflows? • Blue water = salty • Colorless = fresh • What happens when they mix?

15. *Salt water is more dense than fresh water! Fresh water comes in and is on top near river mouths.

16. What factors affect salinity? • Human caused • Natural

17. So how do oceans become salty anyway? • Salts occur naturally in soil on the land. • Rainwater picks up salts in runoff. • Rivers bring salts to the ocean. • Evaporation in the ocean removes water, leaving salt behind. • Over millions of years, oceans become salty.

18. Check for understanding! • 1. Which is more dense – salt water or fresh water? • 2. What river contributes the greatest amount of fresh water in Galveston Bay? • 3. Why couldn’t a juvenile crab live at the mouth of Galveston Bay? • 4. List three abiotic factors that affect organisms in an estuary. • 5. Why is the ocean salty?

19. New Page: • Title: Barrier Islands • Date: check the board!

20. Barrier Island

21. Barrier Island

22. Barrier Island

23. Build it! • One white board • One marker • One playdough

25. Interactive notebook: • Draw what you built. • Include: • Ocean • Bay • Beach • Dune • Swale • Prairie • Wetland • Fresh water • Salt water • Brackish water