Estuaries

in north carolina

TYPES OF ESTUARIES

Trunk estuaries

  • Trunk estuaries run perpendicular to the coast, in line with the rivers that feed them.

Tributary estuaries

  • Tributary estuaries flow into trunk estuaries.

Back barrier sounds

  • Back barrier sounds lie parallel to the coast, between the mainland shore and the barrier islands.

Why estuaries are important

Estuaries help control erosion and reduce flooding of the mainland. Sand bars buffer the impact of waves, while plants and shellfish beds anchor the shore against tides. Swamps and marshes take the initial impact of high winds moving in from the ocean, soak up heavy rain and storm surges, and release the extra water gradually into rivers and groundwater supplies.

Fish and wildlife

Many plants and animals have adapted to the brackish conditions there. More than 150 species of fish and invertebrates live in North Carolina estuaries. Some species use different habitats within the estuarine system during different stages of their life cycles. As in any ecosystem, the plants and animals in an estuary are richly interconnected, and every species depends on several other species to survive.

Geology

North Carolina estuarine environments were formed over many tens of thousands of years as sediment from the erosion of the land and mountains were carried to the coastline by rivers and wind, and sediment that was eroded and deposited during rising and falling sea levels accumulated.


The land under the North Carolina estuaries south of Cape Lookout, which include those fed by the White Oak, New, and Cape Fear Rivers, is composed primarily of sediment (rock) laid down between the Upper Cretaceous and Pliocene periods, 90 million to 1.6 million years ago. Harder rocks such as sandstone and limestone predominate. At some point, geologic forces caused these rock units to rise slightly and tilt. They now slope at an average of three feet per mile and are covered by only a thin layer of sand and mud.

Threats to the estuarine system

The complex ecosystem of North Carolina estuaries is harmed by changes to the land bordering and surrounding the estuaries and by contamination of river and ocean water. Although the North Carolina estuaries contain 3,000 square miles of surface water, 30,000 square miles of land drains into the Albemarle-Pamlico system. As land is developed for human habitation and use, roads, bridges, culverts, sewage systems, pipelines, and dams change the flow of water through the ecosystem. Whereas wetlands soak up water like a sponge and settle contaminants in the ground, asphalt and concrete deflect water so that it runs off with all its contaminants directly into the rivers, estuaries, and the sea.

North Carolina estuaries

NORTHERN BACK-BARRIER SOUNDS


  • Core Sound
  • Pamlico Sound (largest)
  • Roanoke Sound
  • Croatan Sound
  • Currituck Sound


NORTHERN TRUNK ESTUARIES

  • Albemarle Sound estuary
  • Pamlico River estuary
  • Neuse River estuary


SOUTHERN BACK-BARRIER SOUNDS

  • Back Sound
  • Bogue Sound
  • Stump Sound
  • Topsail Sound
  • Middle Sound
  • Myrtle Sound


SOUTHERN TRUNK ESTUARIES

  • North estuary
  • Newport estuary
  • White Oak River estuary
  • New River estuary
  • Cape Fear River estuary


TRIBUTARY ESTUARIES

  • Trent River estuary
  • Bath Creek estuary
  • Scuppernong River estuary
  • South River estuary
  • Bay River estuary
  • Pungo River estuary
  • Alligator River estuary
  • Pasquotank River estuary
  • North River estuary