Gulf Coast of the United States Pensacola, St. Petersburg, Tampa, and increasingly, Sarasota. All are the centers of their respective metropolitan areas and contain large ports. (Baton Rouge is relatively far from the Gulf of Mexico; its port is on the Mississippi River, as is the port of New Orleans.) The Gulf Coast is made of many inlets, bays, and lagoons. The coast is also intersected by numerous rivers, the largest of which is the Mississippi River. Much of the land along the Gulf Coast is, or was, marshland. Ringing the Gulf Coast is the Gulf Coastal Plain which reaches from Southern Texas to the western
Gulf of Mexico Island. The Gulf contains a hypoxic dead zone that runs by east-west along the Texas-Louisiana coastline. In July 2008, researchers reported that between 1985 and 2008, the area roughly doubled in size and now stretches from near Galveston, Texas, to near Venice, Louisiana. It is now about , nearly the record. Poor agricultural practices in the northern portion of the Gulf of Mexico have led to a tremendous increase of nitrogen and phosphorus in neighboring marine ecosystems, which has resulted in algae blooms and a lack of available oxygen. Occurrences of masculinization and estrogen suppression were observed as a result.