Anything that causes water to move can cause a wave: earthquakes, underwater landslides, changes in atmospheric pressure, underwater volcanic eruptions, the movement of ships, or even a fish jumping. The most common cause of surface waves in the ocean, however, is the wind blowing across the water. Once set in motion by the wind, as long as the wave is in deep water, the energy of the waves is passed from water particle to water particle without the water actually moving. The size of a wave depends on how long the wind blows, the strength of the wind, and the distance the wind blows, known as the fetch.
Tides are huge “waves” that are caused by the gravitational attraction between the earth, the moon and, to a lesser extent, the sun. High tide is the crest of the wave and low tide is the trough of the wave. All objects have a gravitational attraction to each other. The amount of gravitational attraction between two objects depends on how close together they are and how large they are. Because the moon is closer to the earth it has a greater effect on the earth’s tides than the sun does, even though the sun is much larger.
Currents are rivers of water in the ocean. The two major types of currents are surface currents and density currents.
Surface currents are driven by the wind. Friction between the wind and the water sets these currents in motion. The winds that drive surface currents are the Westerlies that blow west to east at 40 degrees to 50 degrees latitude and the trade winds that blow east to west at 20 degrees latitude.
Launching a boat can sometimes be a problem. Wind, low tide, a slippery, steep boat ramp, or other local problems may mean hidden hazards. The boat owner can make the task easier by being alert and following this simple procedure. Remember, courtesy and efficiency will go a long way in making a boat trip a pleasure for you and others too.
There are many coastal public water access points throughout Coastal Georgia. Each county has several points of access via public boat ramps. The map in this article shows the locations of those boat ramps. Click the icon to get additional information about each individual facility.
Despite its popular usage, the term “artificial” reef may be somewhat of a misnomer. While the foundation of an artificial reef may consist of manmade structures, the biological community that establishes itself on these materials is very “natural.” Off Georgia, where natural reefs are not based on coral, but rather on rock outcroppings, this distinction may be even less, depending on the type of manmade material deployed.
Intertidal mud flats are located along the edges of the salt marsh. This harsh habitat is covered by water at flood (high) tide and exposed to the scorching sun at ebb (low) tide. It consists of a soggy substrate (soil) made up of clay and silt that is deposited during slack tide. Slack tide is the brief period between flood tide and ebb tide during which the water is not flowing in or out but is still. Only the upper layers of this muddy substrate contain oxygen. The deeper layers contain decaying organic matter that gives off a hydrogen sulfide gas that causes a rotten egg smell.
The sound is the deeper portion of the estuary located between the mud flats and marshes of the mainland and barrier island. The temperature and salinity of the sound varies with the amount of fresh water entering from rivers or rainfall and from mixing with salt water during incoming tides. An increase in rainfall will quickly decrease the salinity and most times the temperature of the water. The substrate or soil type at the bottom of the sound is a direct result of the deposition of mud and sand from the freshwater streams of the drainage basin that empties into the sound. The grain and particle size of this bottom substrate determine the type, distribution and abundance of the organisms that live there.