Lateral Lines: Lateral Lines: Tide Pools Part 1: An Introduction to Tide Pools

In November of 2005 Advanced Aquarist’s Online Magazine
published an article on seashells and seashell collecting
(http://www.advancedaquarist.com/2005/11/lines).
I wrote that article thinking people would enjoy learning more
about marine life, even if the subject matter did not directly
address captive husbandry. It turns out I was correct. Following
the advice of several emails and suggestions future articles will
address similar subjects.

This article is an introduction into tide pools. I’m sure
everyone knows what a tide pool is, but maybe you’ll learn
something from this article, and the articles to come.

TurbidWater.jpg

Tide pools are “clearly” show the
forces of nature as turbid water meets soft sediment.

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TableAcro.jpg

Yet many table across thrive in these
areas.

Three basic laws of survival rule life in the tidepool (GMA 1998):

  1. Keep from being washed away by the waves at high tide
  2. Keep from drying out by the sun at low tide
  3. Keep from being eaten
LoneMangrove.jpg

Pictured here a lone mangrove pod growing in
a tide pool.

What Are Tide Pools?

“Tides are the periodic (occurring at regular intervals)
variations in the surface water level of the oceans, bays, gulfs,
and inlets.” (NDBC 2006) Since water levels are not
constant, neither or shore lines. This produces a shoreline area
of great variability. Tide pools are the shallow water pockets
found along shore lines. These areas of water are usually found
in rocky locations and greatly very in water volume as the tides
rise and decline.

The tides are created by the gravitational forces of the sun
and the moon. The moon (being far closer to Earth) has a much
greater affect on tides. The gravitational forces of these bodies
pull the water on the Earth towards them. Without boring you with
details I’ll just say that there are two low tides and two
high tides per day. The cycle of tides varies daily, but is well
predicted and repeats every 27.3 days. In fact one could argue
that predicting tides is more accurate than predicting when Old
Faithful will erupt.

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podmicro.jpg

Commonly called water bugs are abundant in
tide pool systems.

What Lives in a Tide Pool?

Lots of interesting little things. That sums up the fauna of
tide pools but more specific examples are to follow. To provide a
list of what you can find in tide pools is impossible. The
biodiversity varies greatly between the shorelines around the
world. Here are some examples, but this is just a
glimpse….

Algae

Everyone’s favorite item is abundant in many tide pool
areas. While an argument can be made for coral reefs really being
algal reefs it is also true that algae spp. are very successful
in tide pools. Without much investigation or attention even a
small child can recognize that a tide pool is a bunch of wet
rocks covered in algae.

In this author’s opinion their may be nothing on this
planet of more beauty than wet rocks covered in algae.

AlgaeCover.jpg

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Even Chlorophyta macro algae can not escape
the cover of debris in tide pools.

Corals

Yes even corals are found in tide pools. The thrashing waves,
intense light, exposure to air, and threats from predators are
not enough to keep them away. Often found in brilliant colors the
corals of tide pools are not to be overlooked.

TideCoral.jpg

Only a couple inches below the water surface
this colorful Acropora sp. displays vibrant colors.

Fishes

Can you find fishes in tide pools? Absolutely. I feel
confident in saying you can find fishes in just about every body
of water on the planet. Tide pools are certainly not an
exception. Many fishes live in tide pools throughout their lives,
while other fishes may seek protection in the cracks and crevices
while juveniles.

TideFish.jpg

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Tide pools are home to many fishes. Some
like those shown here appear as flashes of color as they dart
around their coral homes.

TideEel.jpg

An eel is shown poking its head out if its
home.

Arthropods

Shrimp and crabs. These creatures are fun to watch and
exciting to find. Small crabs can be found on rocks, sand,
underwater, riding the waves, and simply holding on for dear
life. The have very small claws, or very large, or anywhere in
between. Just as pleasurable to see is their odd little sideways
shuffle across the substrate. It is also important to mention
that most of the Arthropods found in tide pools are animals too
small for us to easily see. Microcrustaceans exist in huge
numbers. I mean huge numbers. This general classification
includes Mysids, Amphipods, and Copepods. Interesting side note-
Copepods are the most abundant form of multicellular life on the
planet.

Stomatopod.jpg
Amphipod40x.jpg
Copepod40x2.jpg

Arthropods are everywhere. Shown here is a
yellow stomatopod scurrying along a shallow pool, while
amphipods and copepods are rarely seen with the naked eye.
These two photographs have been taken at a 40x
magnification.

TideLobster.jpg

Shown here a Caribbean Lobster hides in a
cave.

Mollusks

In general Mollusks can be divided into two tide pool
categories. The first type is the common small Mollusks, snails.
While maybe not the most sought after find, snails are very
important to tide pools. They seem to form colonies in very high
numbers and populate just about every shore line in the world.
The second type of Mollusks are the big exciting and intelligent
animals; namely Octopus and Squid. Word of warning- if you see
one of these marvelous animals it would behoove you to keep some
distance. While not aggressive you can’t blame them for
defending themselves and their home.

A final note regarding Mollusks: they are the creators of
those wonderful seashells that so many love to find and examine
(http://www.advancedaquarist.com/2005/11/lines).

TideOctopus.jpg
TideSquid.jpg

While an Octopus crawls over the rocky
shore, a group of squid sway in the waves.

Echinoderms

Echinoderms are the treasures of tide pools. They are the
reason people like me will drive 1500 miles with their children
screaming in the backseat. To turn over a rock in knee deep water
and uncover a seastar is an exciting event. The same can be said
for sea urchins which in some places litter the shores. These
often overlooked animals are continuously grazing, fighting,
reproducing, and living in the rocky pools where ocean meets
land.

TideSeastar.jpg

Against the brown background this blue
linckia star (Linckia laevigata) would be difficult to
oversee.

Worms.jpg

Ooh, what are those wormy things? I
don’t know but you better not touch them.

Conclusion

For children (and adults) the love, appreciation, and respect
derived from experiencing tide pools are wondrous.

Acknowledgments

This project was funded by the Aquatic & Terrestrial
Research Team. Microscopic photographs contributed by Adam
Haycock. I’d like to thank the many, many people who helped
contribute to this project over the years. This project was the
result of years of observation and discovery. It shows that
friendships, photographs, and a sense of adventure can go a long
ways.

References

  1. Blundell, A., (2005) “Beachcombers – Those Seashell
    Lovers”, Advanced Aquarist’s Online Magazine,
    http://www.advancedaquarist.com/2005/11/lines.
  2. GMA, (1998) “Tidepool: Window into the Sea”, Gulf
    of Maine Aquarium, website publication,
    http://octopus.gma.org/katahdin/tidepool.html.
  3. NDBC (2006) “NDBC Science Education Pages”,
    National Data Buoy Center, website publication,
    http://seaboard.ndbc.noaa.gov/educate/tides.shtml.

Author Information

Adam Blundell M.S. works in Marine Ecology, and in Pathology for the University
of Utah. He is also Director of The Aquatic & Terrestrial
Research Team, a group which utilizes research projects to bring together hobbyists
and scientists. His vision is to see this type of
collaboration lead to further advancements in aquarium husbandry.
While not in the lab he is the former president of one of the Nation’s
largest hobbyist clubs, the Wasatch Marine Aquarium Society
(www.utahreefs.com).
Adam has earned a BS in Marine Biology and an MS in the Natural Resource and
Health fields. Adam can be found at adamblundell@hotmail.com.

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 Adam Blundell

  (44 articles)

Adam Blundell M.S. works in Marine Ecology, and in Pathology for the University of Utah. He is also Director of The Aquatic & Terrestrial Research Team, a group which utilizes research projects to bring together hobbyists and scientists. His vision is to see this type of collaboration lead to further advancements in aquarium husbandry. While not in the lab he is the former president of one of the Nation's largest hobbyist clubs, the Wasatch Marine Aquarium Society (www.utahreefs.com). Adam has earned a BS in Marine Biology and an MS in the Natural Resource and Health fields. Adam can be found at adamblundell@hotmail.com.

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