Chapter 10-11 Quiz

Fjord

Former glaciated valley now flooded with seawater, U-shaped estuaries typically have steep sides, rock bottoms, and underwater sills; The shallowest area of the estuary occurs at the mouth, where terminal glacial deposits or rock bars form sills that restrict water flow

Depositional shores

Gradually subsiding shore, barrier islands and sand deposits are common

Wintertime beach

Heavy wave activity (Backwash dominates, Sediment moved away from shore, Narrower beach, Flattened beach face), Longshore bars are present, stormy weather

Coastline

boundary between shore and coast

Halocline

caused by a strong, vertical salinity gradient within a body of water

Ocean beach

closest part of the island to the ocean, older peat deposits found here

Mangrove swamps

coastal wetlands in tropics

Spit

connects one end to the mainland and hooks into a bay at the other

Peat deposits

decaying organic matter

Berm

dry, gently sloping region

Beach

entire active area of a coast affected by waves

Coast

extends inland as far as ocean related features are found

Wave-cut bench

flat, wave-eroded surface

Sea stacks

form when the tops of sea arches erode away completely

Sea arches

form where sea caves in headlands erode all the way through

Nearshore

from low tide water line to where waves break at low tide

Barrier flat

grassy area that forms behind dunes

Low Latitudes

restricted circulation, very warm, may be isothermal

Tombolo

sand bar that connects an island to the mainland

High latitudes

sea ice, may be isothermal

Bay barrier

seals off a lagoon from the ocean

Longshore trough

separates longshore bar from the beach

Dune

stabilized by grasses; protect lagoon from strong storms

Middle latitudes

strong thermocline may develop

Shore

the zone that lies between the low tide line and the highest area on land affected by storm waves

Longshore current

transports sand along the beach

Longshore bar

underwater sand bar parallel to the coast

Lagoon

water between barrier island and mainland

Backwash

water drains back to the ocean

Swash

water rushes up the beach

Beach face

wet, sloping surface between berm and shoreline

Marine terrace

Bedrock uplift

Salt Marshes

Between 30 and 65 degrees latitude

Breakwaters

Built parallel to a shoreline, Designed to protect harbors from waves, Can cause excessive erosion, requiring dredging to keep area stable

Jetties

Built perpendicular to shore, Built in pairs, Built to protect harbor entrances

Groins

Built perpendicular to the beach (Often made of rip rap, or large blocky material), Traps sand upcoast, which can cause erosion downstream of the longshore current, May necessitate a groin field, or a series of groins built along a beach

Freshwater runoff

Can produce well-defined halocline

Wave refraction

Causes zigzag motion of water in surf zone

Law of the Sea

Coastal nations jurisdiction, Right of free passage for ships, Open ocean mining regulated by International Seabed Authority, United Nations arbitrates disputes

95%

Coastal waters support about _____ of the total biomass in the oceans

Salt wedge

Deep, high volume, Strong halocline

Highly stratified

Deep, relatively strong halocline

Slightly stratified

Deeper, Upper layer less salty; lower layer more salty, Estuarine circulation

Seawalls

Destructive to environment, Designed to armor coastline and protect human developments, One large storm can remove beach, Wave activity eventually undermines seawall structure; need continual repair or will collapse

Coastal wetlands

Ecosystems intermittently inundated with ocean water, Peat deposits and halophytic plants, Nurseries, feeding grounds for commercially important marine animals, Efficiently cleanse polluted water, Absorb water from coastal flooding, Protect shores from wave erosion, Have piles of climate information

Tectonic estuary

Faulted or folded downdropped area now flooded with ocean formed by subsidence or land cut off from the ocean by land movement associated with faulting, volcanoes, and landslides

U.S. Office of Wetland Protection

1986, Minimize loss of wetlands, Protect or restore wetlands

Exclusive Economic Zone (EEZ)

200 nautical miles (370 km) from land (mineral and fishing resources)

Coastal Waters

Adjacent to land (to edge of continental shelf), Influenced by river runoff, wind, tides, Salinity variable (Freshwater runoff, Winds, Mixing by tides, Temperature variable; seasonal changes, prevailing winds)

Bar-built estuary

Lagoon separated from ocean by sand bar or barrier island estuaries are semi-isolated from ocean waters by barrier beaches, islands, spits. Only narrow inlets allowing contact with the ocean waters

Summertime beach

Light wave activity (Wide, sandy berm, steep beach face, Swash dominates), Longshore bars not present, generally milder storms

Gulf Coast

Low tidal range, Generally low wave energy, Tectonically subsiding, Mississippi delta dominates (Locally sea level rises due to compaction of delta sediments), Average rate of erosion is 1.8 meters (6 feet) per year

Longshore transport

Millions of tons of sediment moved yearly, Direction of transport changes due to wave approach, In general, net sediment movement is southward along the Atlantic and Pacific coasts of the United States

Atlantic Coast

Most coasts open to storm wave attack, Barrier islands common from Massachusetts south, Bedrock (Florida is made from Limestone), Strong storms called nor'easters can damage the coast north of Cape Hatteras, NC., Nor'easters can generate storm waves up to 6 meters (20 feet), Drowned river valleys common, erosion 0.8 meters/yr (2.6 feet)

Relocation

Move structures rather than protect them in areas of erosion

Longshore Current

Parallel motion of water along shoreline, Caused by wave refraction, Longshore currents travel at speeds up to 4 km (2.5 miles) per hour, Also called longshore drift, beach drift, or littoral drift, Only occurs in the shallow water surf zone, "rivers of sand"

Estuaries

Partly enclosed body of water, Freshwater runoff dilutes ocean water, 4 types; coastal plain, tectonic, bar-built, and fjord

Headland

Protruding bits of land absorb much wave energy

Beach replenishment

Sand added to beach/longshore current, Expensive; costs between $5 and $10 per cubic yard, Sand must be dredged from elsewhere

Vertically mixed

Shallow, low volume

Construction restrictions

Simplest alternative to hard stabilization, Limit building near shorelines

Hard stabilization

Structures built to decrease coastal erosion and interfere with sand movement, Also called armoring of the shore (some structures may increase erosion)

Pacific Coast

Tectonically rising, Experiencing less erosion than Atlantic or Gulf coasts, Open exposure to high energy waves, Average rate of erosion 0.005 meters (0.016 feet) per year

Coastal plain estuary

Well-developed drowned river valleys are generally found on coastlines with low, wide coastal plains Ex: Hudson River, Chesapeake Bay, and Delaware Bay

Mixing by tides

Water may be isohaline

Erosional shores

Well-developed cliffs, Exist where tectonic uplift of coast occurs, U.S. Pacific coast is one example

Isothermal

a change of a system, in which the temperature remains constant

Isohaline

a line or surface drawn on a map or chart to indicate connecting points of equal salinity in the ocean

Thermocline

a steep temperature gradient in a body of water such as a lake, marked by a layer above and below which the water is at different temperatures

Backshore

above high tide line; covered with water only during storms

Barrier islands

are long offshore sand deposits that parallel the coast, Most developed due to rise of sea level about 4,000 years ago, Common East and Gulf coasts of U.S., Protect mainland from high wave activity, can migrate landward over time

Wave-cut cliffs/Sea caves

are other features carved out by wave activity

Recreational beach

area above the shoreline

Offshore

area beyond low tide breaking waves

Salt Marshes

biologically productive wetlands