Chesapeake Bay Chesapeake Bay History
Formed 12,000 years ago when the lastgreat ice sheet melted, filling the ancientSusquehanna River. Our current coastline is approx. 70 milesmore inland than the original shoreline. The FIRST incarnation of the bay area wascreated by a meteorite. The PRESENT day Chesapeake Bay wasformed from the last ice age. Chesapeake Bay Statistics
The largest estuary in N. America.(2500 sq mi) 200 mi. long and 30 mi. wide Over 15 million live in the Chesapeakes watershed, whichspreads across six states: Virginia, West Virginia, Maryland,Delaware, Pennsylvania, New York and Washington D.C principle rivers 400 lesser streams and creeks Has more than 4,600 miles of tidal shoreline The bay hosts nearly 350 species of finfish and almost 175species of shellfish. The Watershed of the Bay
Def.-An area of land that is drained by ariver or other body of water. Six states make up the Ches. Bay watershed:
1.Virginia 2.New York 3.Pennsylvania 4.Maryland 5.Delaware 6.West Virginia Main Rivers of the Bay There are 5 main rivers of the shore:
1.James River 2.York River 3.RappahannockRiver 4.Potomac River 5.Susquehanna River The Rivers of the Bay Rivers on the westernshore are generally largerthan those on the easternshore. The eastern shore ischaracterized bymarshlands and support avariety of waterfowl. 52% of the baysfreshwater comes from theSusquehanna River (mainriver of the bay) Depth of the Bay The bay is very shallow.
The average depth is only 20 feet. The deepest spot is near Annapolis, MD andis approximately 180 ft. deep. The bays world-famous oyster and soft- shelled clam harvests are due to the amountof suitable shallow water of the bay. Seasons of the Bay: Spring
A resurgence of activity; migratory speciessuch as fish and crabs move toward thewarming shallows from deeper parts of theocean. Shads and herrings move upstream to spawn. Invertebrates begin to grow and reproduce. Seasons: Spring to Summer
Many fish enter the bay to feed on theabundant schools of smaller fishes such asanchovies and menhaden. Seasons: Fall and Winter
Species begin to migrate out of the bay. Activity and growth decline. In winter months, many animals seek thedeeper areas of the bay for warmth. How Salty is the Water? Salinity increasesgradually downstream(towards the ocean). Midway downstream it is12 ppt (about that ofthe ocean). Salinity also increasesfrom the surface to thebottom.(2-3 ppt saltier) Salty water is heavier so itsinks below the less saltywater. Zones of the Bay Zone 1 tidal freshwater Zone 2
slightly brackish tomoderately salty - upper zone is 1-10 ppt lower zone is ppt Zone 3 salinities 18ppt to oceansalinities of 30+ ppt - many oceanic animals livehere as well as estuarinespecies Salinity Determines.
No matter what the habitat a beach,marsh, intertidal flat SALINITYdetermines the kind of species that livethere.