Tides

By: Ireland Barber

The Movement of Tides

Tides are the rise and fall of the ocean due to the gravitational pull of the sun, moon, and rotation of the Earth; a periodical rise and fall of the sea level. When the water level is falling it is called an ebb, the time between the low tide and high tide when the tide is rising is the flow or flood. The highest tides in the world occur at The Bay of Fundy in Nova Scotia, Canada.


Types of Tides

Based on frequency, there are three types of tides, they are the Semi-diurnal, Diurnal, and the mixed tide, the most common being the Semi-diurnal tide. The Semi-diurnal tide has two high and two low tides that are approximately the same height. Two types of tides based on their height, or the position of the sun, moon, and, Earth, are Spring Tides and Neap Tides. Spring tides occur when the sun, moon, and Earth are in a straight line. They occur twice a month and occur during the full, and new moon, phases.


What Is the Importance of Tides?

Tides are important because they help fisherman and navigators to plan their activities due to being based on the position of the sun, moon, and Earth. Tidal flows, or the time between high and low tide, when the tide is rising, helps with navigation. Tidal heights are important because of shallow bars that prevent boats from entering into the harbor. When the tide is high boats can pull in without worry. Another reason tides are so important is that they are helpful in desilting the sediments, as well as removing polluted water from river estuaries. Finally, tides help generate electrical power in many countries.


High and Low Tide Zones

High tide zones are drastically different from low tide zones. In the high tide zone the creatures here are scarce consisting mostly of seaweed and invertebrates. This is because the high tide zone is flooded during high tide and so the creatures here have to endure wave action, currents, and sun exposure. In the low tide zone the sub-region is mostly submerged, until low tide. It teems with life and biodiversity, this is because these creatures do not have to worry about drying out or extreme temperatures. Also, since the water is shallow they can photosynthesize easier and become very healthy. They are also protected a bit more from predators due to wave action and being in shallow waters.