Freshwater inflows from rivers and bayous meet saltwater from the Gulf of Mexico

Fresh + Salt = Brackish water

List 1: Dissolved Oxygen Tides Wind speed and

direction Salinity Water depth

List 2: Brown shrimp Oysters Chord grass Dolphin Blue crab Red drum

Freshwater inflows from rivers and bayous meet saltwater from the Gulf of Mexico

Fresh + Salt = Brackish water

On your map, add shading: more blue near mouth of rivers and bayous,

More yellow at mouth of Bay

Trinity River – 54% inflow

San Jacinto River – 28% inflow

Add these numbers to your map!

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)

Title: Abiotic Factors in an Estuary

Date: check the board!

Important abiotic factors in Galveston Bay Dissolved Oxygen Tides Wind speed and direction Salinity Water depth Nitrates/Phosphates pH

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

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.

Blue water = salty Colorless = fresh

What happens when they mix?

Natural Human caused

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.

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?

Title: Barrier IslandsDate: check the board!

One white board One marker One playdough

Draw what you built. Include:

◦ Ocean ◦ Bay ◦ Beach◦ Dune◦ Swale◦ Prairie◦ Wetland

◦ Fresh water◦ Salt water◦ Brackish water