San Dieguito River Park
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How do the tides affect the lagoon and all the animals that live here?
Lagoons are areas of constant change. These changes range anywhere from bird migration to tidal flow to precipitation levels. The tidal variation within a lagoon is constantly changing. A tide is described as the alternating rise and fall of the sea level with respect to the land and is produced by the gravitational pull of the moon and the sun. There are two types of tides that occur in different locations all over the world. There is a semi-diurnal tide, which is two high tides and two low tides per day, and a diurnal tide, which is one high tide and one low tide per day. There are 2 different levels of measurement for tides, called Spring Tides and Neap Tides. A spring tide creates high tides that are very high and low tides that are very low and occur when the moon, sun and Earth are all aligned. Neap tides are much weaker because they occur when the moon, sun and Earth are perpendicular to each other.
The San Dieguito Lagoon is considered a mixed tide where the semi-diurnal tides alternate with periods of diurnal tides. This creates a constantly changing landscape where animals and plants alike must survive through periods of no water and periods of an overflow of water. Plants and animals that live in the lagoon regions have evolved to compensate for this constantly changing habitat.