Beach Profiling

Our class has been Profiling Kalepolepo beh, which has lived up to it's dirty, dirty name. On our site, there's a pond, which effects the distribution of sand, dun  restoration, which reshapes the beach, and many other man made factors that effect this area.

(Allie and Lucas measuring carefully with the Rise/Run tools

as we follow the transect over the hill)

(Holly and Lucas getting help from Ms. S at the beginning of our transect)

Procedure:

1)   Gather your materials: Transect tape, GPS, compass, Rise and Run tool, data sheet, and pencil or pen. 2)  Head out to the beach!

3)  Once you find a good dune er’ two, pick one and find the latitude and longitude coordinates of that dune using your remarkable GPS tool. Record these on your data sheet as “Point A”
4)  Now lay your transect tape out stretching from Point A to the shoreline, making sure it is perpendicular to the waterline
5)  Then hold the compass at Point A to find out the degree/direction of the transect line laid out. Record this reading!
6)  Place the Run tool on the ground and Point A aligning with the transect tape (pointing downwards) and use the level to make it level (Ha!)
7)   Now place the Rise tool at the end of the Run tool and use the level to make sure it’s even. This is Point B
8)  Look to see where the Run tool intersects with the Rise tool and record is at the Rise between points A and B. This number (if the dune tilts up) should be a negative number.
9)  Note any distinctive features that stick out between the two points and on the dune
10) Now move the foot of the Run tool to the foot of the Rise tool (making sure it’s at the same point) and remove the Rise tool from that spot. Make sure the Run tool remains level and perpendicular to the water line
11) Then take the Rise tool and place it so it’s touching the end of the Run tool, like #7, and make it level again
12) Repeat steps 10 and 11 until you get to the “foot of the beach” in the water, past the shoreline. 

Where is the Sand From?

Sandy beaches are everyone's favorite. Where does the sand come from? There are two types. Biogenic sand comes from something once living (shells, exoskeletons, coral). Detrital sand comes from rock that's eroded To assess our data from given beaches, we will test our sand using vinegar to find out if it contains calcium carbonate (which will create a bubbling reaction if it's biogenic).

vinegar  + calcium carbonate = calcium acetate + water + carbon dioxide (the bubble effect)

Less popularly known as: 2CH3COOH + CaCO3 = Ca(CH3COO)2 + H2O + CO2

Question: Which beaches on south Maui (Kihei area) will turn out to be biogenic, and which will be detrital?


Hypothesis: I predict that Big beach will be a biogenic beach, and black sand beach will be primarily detrital.
If the sand reacts to the vinegar, it will be biogenic, and otherwise detrital.


Materials: Journal, pen, cup (for sand), vinegar, pipette, map, and sand.

Procedure:
1. Gather materials
2. Make observations of chosen beaches
3. Collect sand from chosen beaches
4. Test the sand with vinegar using 20 drops from the pipette
5. Record your data after determining it's origin

    Makena Beach (Onelua)

   

    Black Sand Beach

Makena Beach: This beach is long, and white, with fine sand and Keawe shade. There is a dead reef offshore, which produces sand, and harbors the coast from much erosion.

Black Sand Beach: This beach is hidden, and often shaded by trees and high rock that surrounds it. It has grainy salt and pepper sand. The surrounding rock seems like it has eroded a lot, producing sand for this beach.

Data: Big beach's sample bubbled the most of any sample we tested, with lots of popping, which means it's a biogenic beach. Black Sand beach made no bubbling, with slight popping, and it's results suggested it was detrital.

Conclusion: The purpose of this lab was to find whether certain beaches on south Maui were biogenic or detrital. After testing our samples, we found that Black Sand beach was primarily detrital, and Big beach was biogenic. The results from our sampling matched my hypothesis almost exactly.

Possible Sources of Error:

•  failed to observe certain reefs, cliffs, or other factors
• added the wrong amount of vinegar to our samples
• mislabeled our sand samples
• recorded our data incorrectly