What is a Tide Pool?

Isn’t it amazing to think that as the tide moves out, a whole new world is created along the rocky coastline?  These new worlds, aka tide pools, are extremely important to the dynamics of central California coastline because they provide food and shelter to a number of fish and invertebrate species.  But how are these tide pools formed?

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When it comes to our tides, the gravitational pull of our moon and sun are key players.  As their gravitational pulls acts on our planet, tidal bulges form on opposite sides of the Earth due to gravity and inertia - both a lunar and a solar tidal bulge will form.  As the moon rotates around Earth and Earth rotates around the sun, the angles of these tidal bulges change.  These changes in tidal bulge angles directly affect our tides.  The most extreme tides occur when the moon, Earth, and the sun are aligned with one another.  These extreme tides are referred to as spring tides – this is when we will have very high high tides and very low low tides.  More moderate tides occur when the moon, Earth, and sun are aligned in a 90 degree angle.  These moderate tides are referred to as neap tides.

Some may think that tide pools are simply puddles of water along the coast.  This is a huge understatement!  Just like our ocean is broken into different depth zones, the same goes with tide pools.  Three major zones are present within all tide pools – the splash zone, intertidal zone, and subtidal zone.  But what do these zones mean and what life can be found within them?

To begin our journey, let’s start at the very top, the splash zone.  This zone is by far the harshest zone to live in because only water present is from the occasional spray or mist from the ocean.  As a result, this zone is very hot due to the constant exposure to the sun as well as extremely salty due to constant evaporation.  Because these conditions are pretty rough, very little life is found in the Splash zone.  Some algae and an occasional barnacle can be found living within the splash zone but other than that, life is pretty much nonexistent in this zone.

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As we travel farther down the tide pool and enter the intertidal zone, life becomes ever more present as the conditions become more ideal.  Since the strength of tides vary day to day, three subzones have been created within the intertidal zone: the high, mid, and low intertidal zone.  The high intertidal zone is located directly under the splash zone and is only covered with water during the highest of high tides.  Although more life will be found in this zone than the splash zone, compared to the rest of the pool life is still relatively low.  Barnacles, snails, and crabs begin to appear as well as the occasional anemone.  As we descend even further into the mid and low intertidal zones, the amount of water, food, and shelter significantly increase as does the amount and diversity of the wildlife.  Anemones, crabs, snails, sea stars and more can be found in these ideal conditions.

The deepest and final zone within tide pools is referred to as the subtidal zone.  Water will almost always be present in the subtidal zone and as a result, many bottom dwelling invertebrates and even fish can be found within it!

So the next time you find yourself on the coast, "tide pooling" is a must because it’s easy as 1, 2, 3!  All you need is a bucket, some friends, and the ocean for a good time!

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Sources:

“Tidal Zones.”  Oregon Tide Pools, http://oregontidepools.org/tidalzones

US Department of Commerce, National Oceanic and Atmospheric Administration. “Why Do We Have Spring Tides in the Fall?” NOAA's National Ocean Service, 1 Aug. 2014, https://oceanservice.noaa.gov/facts/springtide.html