Geology 18.8-18.9

Coastal plain

low-relief regions of land adjacent to the coast

Example of Coastal Plane

Gulf Coast & southeastern Atlantic coast of the US

Emergent coasts

a coast where the land is rising relative to sea level or sea level is falling relative to the land

submergent coast

a coast at which the land is sinking relative to sea level

Example of emergent coast formation

step-like terraces

Example of submergent coasts

estuaries and fjords

Erosional coasts

when waves wash sediment away faster than it can be supplied. Coastlines recede landward and may become rocky

Accretionary coasts

coasts that receive more sediment than the sea erodes away, grows seaward and develops broad beaches or tidal flats

Carbonate platform

thick accumulations of shelf carbonate sediments with this characteristic flat-topped morphology

Storm Surge

a mound of seawater driven landward by wind during a storm

What increases storm surge height

the low atmospheric pressure beneath the storm that allows sea level to rise locally

Beach erosion

the removal of beach sand caused by wave action and longshore currents

Groins

concrete or stone walls perpendicular to the shore

Jetties

a pair of walls used to protect the entrance to a harbor— constructed at the mouth of a river channel and effectively extend the river into deeper water.

Breakwater

an offshore wall built parallel to the beach to prevent the full force of waves from reaching a harbor

Seawalls

riprap/reinforced concrete that reflect wave energy back across the beach to the sea

Beach nourishment

a procedure in which sand is pumped from farther offshore or from a truck in order to replenish a beach

Dead zone

a region in which water contains so little oxygen that fish and other organisms within it die

How do dead zones form?

when the concentration of nutrients rises enough to stimulate an algal bloom. The algae deplete dissolved oxygen in the water, causing decay

Reef Bleaching

the loss of coral color due to the death of the algae that live in coral polyps