Cape Fear estuaries: Introduction

A map showing some of the locations along the Cape Fear River visited in this field trip. Click to see a larger map. (Satellite image from NASA with map drawn over top. More about the map)

A quiet afternoon on the dock overlooking the Cape Fear estuary, fishing with friends. A gentle breeze clatters the marsh reeds and sends ripples floating across the water. A vision of stability and tranquility.

Unfortunately, this vision is entirely misleading. Estuaries are anything but stable and rarely tranquil! Estuaries exist in the midst of counteracting forces — physical, chemical, biological, and political. A balance of river flow and tidal forces shape and define an estuary. The chemical makeup of seawater and, increasingly, the nutrient and pollutant loads in river waters constrain the ability of organisms to live and reproduce.

The competition for resources among the plants and animals of estuaries is most noticeable — for example, a heron about to spear a fish in its beak. But competition and predation occur at microscopic levels as well, among bacteria and plankton that are the basis for estuarine food webs.

Political struggles make the newspapers, though: increasing pressure to develop land to accommodate the 50 percent of the U.S. population living near the coasts; how and whether to restrict industrial and agricultural use of the land draining into North Carolina’s coastal rivers; how to define water quality that reflects human uses of water as well as natural variations in chemical composition or clarity. The drainage area (watershed) for the Cape Fear River is home to 27 percent of North Carolina population, and 25 percent of the watershed is devoted to agricultural uses. It is no surprise that many people are concerned about the quality of the water. Several state agencies are cooperating to monitor and evaluate the quality of this and other rivers in North Carolina.

But the political debates will not deter us from enjoying a trip through the Cape Fear River estuary. The Cape Fear river system is the largest in the state, reaching 200 miles into the piedmont near Winston-Salem. As a result, the river carries a high load of clay and silt, giving the water a brown coloration. Not surprisingly, the Cape Fear River is known as a brown water river. Rivers with less clay and silt may be know as blackwater rivers if they have substantial inputs of organic matter (see the White Oak River tour for more on blackwater rivers). Our tour will start just North of Wilmington, and will include several stops before we reach Bald Head Island and the inlet to the Atlantic Ocean. Fasten your seat belts, because we will be taking this trip by plane, not by boat!

next