Ecosystem #1: The Beach!
Brainstorm! What are some of the abiotic & biotic factors on a beach? Sand, water, waves, wind, sun, rocks, things people brought, etc. Biotic Plants & animals
Beach An accumulation of unconsolidated sediment extending from the low tide line to some feature (like a cliff, dune or permanent vegetation).
Tidal Zone The area of the beach that is sometimes covered in water and sometimes completely dry.
Draw in your Notes: Scarp Berm
Define the Terms on the Diagram as they relate to the beach: Beach Berm Scarp Swash Zone Surf Zone Breaker Zone
Nearly flat back portion of beach formed by material deposited by waves. BERM SCARP Nearly vertical cut into the beach profile formed by wave erosion. Where the beach face is alternately covered by the run up of the wave swash & then exposed again. SWASH ZONE
Where small waves occur following a wave breaking. Surf Zone
*where the waves become unstable & break Breaker Zone
Directions: On a piece of drawing paper, trace the bottom of a beaker to produce 6 circles. Number them 1-6. At each lab table, you will find a different sample of sand. Place a pinch of the sand on a slide and observe. Accurately draw what you see. It is important that you pay attention to the shape of the sand and the colors that you see. Take your time! Return the sand to the original container
On the back… What are some of the things we can learn about a beach by looking at a sample of its sand? What can you infer about each one of your samples?
By observing sand, what can you infer about the beach it came from? Wave energy/time spent in the ocean The presence (or absence) of certain types of animals Nearby natural features/landforms
What is sand? Natural, unconsolidated material composed of grains that are either minerals, rock fragments or biogenic in origin (organic matter) Quartz is the most abundant mineral on our beaches (very durable) Washed down rivers from the Appalachians
Where Does Sand Come From? The Continental Shelf is the largest source of sand
S. Florida Beach Re-nourishment Read the article and answer the questions….
Beach Morphology
What Causes a Beach to Look Different Over Time? Wind Water (waves, tides, currents) Storms Seasons Human Activities
The movement of weathered materials from one place to another Erosion The movement of weathered materials from one place to another
Erosion Sand is the result of weathering Erosion moves sand to new locations Sediment eroded inland also travels in rivers and is deposited into the ocean Sediment is distributed along the edge of the continent by longshore currents
Longshore Transport (Drift) Movement of sand and sediment parallel to the coastline
Longshore Current The actual current (located in the surf zone & running parallel to shore) that moves sand and sediment.
Video Clip Beaches
Dynamic Equilibrium The changes a beach undergoes due to changing seasons (cycle) Summer – wave conditions move sand onto the beach Winter – storm waves pull sand offshore and form sandbars
Summer Winter
Summer Beach Profile
Winter Beach Profile