UMass Amherst GEO-SCI 103 - Coastal Environments and Habitats (4 pages)

Previewing page 1 of 4 page document View the full content.
View Full Document

Coastal Environments and Habitats

Previewing page 1 of actual document.

View the full content.
View Full Document
View Full Document

Coastal Environments and Habitats


Assessment and analysis of the beaches, barrier islands, spits, deltas, estuaries, salt marshes and fertile oases.

Lecture number:
Lecture Note
University of Massachusetts Amherst
Geo-Sci 103 - Intro Oceanography GenEd: PS
Unformatted text preview:

GEO SCI 103 Lecture 20 Outline of Current Lecture Coastal Environments and Habitats pgs 242 245 I Beaches Barrier Islands and Spits II Deltas Estuaries Salt Marshes and Fertile Oases Current Lecture I Beaches Barrier Islands and Spits Beaches and dunes are dynamic environments that always change Beaches respond to seasonal changes in wave intensity and storm activity In the offshore area of the continental shelf seaward of the breakers the amount of sand decreases with increasing water depth This neritic sediment is a mixture of sand silt and clay A Beaches a Deposits of unconsolidated sand or gravel that accumulate along shores subject to the high energy of wave action b Beach barrier islands form when longshore drift shapes the sediments into low lying ribbons of sand that generally parallel the coastline c Spits finger like extensions of sand that jout out from shoreline parallel to direction of longshore drift d Barrier islands and spits develop along coastlines with a wide continental shelf and ample sand supply from river runoff or from erosion of coastal deposits e Food prone and easily eroded but serve as a natural buffer zone f Coastline highest elevation on the continent affected by storm waves g Shore area from low tide line to coastline that is subdivided into two different zones h Backshore flat area from high tide line to coastline i Foreshore area from the low tide shoreline to the high tide shoreline j Berm flat area of sand that accumulates just above high tide k Low tide terrace second flat area generally develops on the foreshore These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute B C D E l Beach face sharply incline surface between the berm and the low tide terrace that is cut by waves during high tide m Dunes linear ridges of unconsolidated wind blown sand that accumulates above or beyond most storm waves Low Energy environments a Marshes and tidal mudflats b Typically receive fine grained sediments and water from washover fans and they are very biologically productive since they are sheltered from direct impact of storm waves c Associated with bay or lagoon between the mainland and the barrier island Sand Bars a Nearshore zone between low tide shoreline and where the breakers are called the surf zone b These linear ridges of unconsolidated sand often trip the incoming waves to start breaking c Dynamic shifting location and change once daily or seasonally d Summer sand bars are closer to the shore e In the winter sand bars form farther from the beach tripping the breakers to reduce the force that large breakers have off the breach Summer beach profile a Gentle fair weather waves move sand shoreward b Net movement of sand is onshore c Summer or recreational beach is piled high with sand Winter beach profile a Winter storm waves move sand seaward b Net movement of sand is offshore c Beach profile is flattened d Nearshore sand bars tend to protect the coast by dispersing wave energy II Deltas Estuaries Salt Marshes and Fertile Oases The abundance of nutrients and sunlight and the daily tidal mixing stimulates the high biological productivity in estuaries and marshes Estuaries occur where the river valleys have been drowned by rising sea levels They have variable environments depending upon the balance between the flow of fresh water and sand sea water into the system A Deltas a Accumulations of sediment at the mouth of a river b Form where a river transports more sediment than can be carried away by longshore currents c Food plain and marshes that border the distributary river channels are biologically highly productive B Estuaries a Highly productive areas of the coast where the fresh water of a river meets the salt water of the ocean mouths of rivers bays drowned river valleys b Salinity of the brackish waters mixture of fresh and salt water in an estuary varies daily and seasonally as well as from top to bottom or from side to side across the estuary c Circulation in estuaries are characterized by low salinity water flowing seaward over saltier water being pushed into the estuary by the tides d Physical and chemical and biological characteristics vary considerably from estuary to another e River volume and tidal mixing are important variables f Salt wedge estuary river dominated as a consequence of the great volume of river water and minimal impact of tidal mixing g Halocline stratifies estuary h Well mixed estuary tide dominated i Partially mixed estuary intermediate between the salt wedge and well mixed types C Salt Marshes a Vegetated tidal flats found along shores protected from the pounding surf b Marshes border estuaries c Develop at the edges of bas and lagoons behind the barrier islands and spits d Dense community of salt tolerant grasses and other plants colonize the intertidal marsh surface e Dissected by tidal creeks which conduct the daily food and ebb of the tides f Nutrients and detritus are flushed in and out of the marsh with each tidal cycle g Mangrove trees dominate the intertidal vegetation instead of grasses

View Full Document

Access the best Study Guides, Lecture Notes and Practice Exams

Loading Unlocking...

Join to view Coastal Environments and Habitats and access 3M+ class-specific study document.

We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Coastal Environments and Habitats and access 3M+ class-specific study document.


By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?