![Porto Covo February 2009-2](https://upload.wikimedia.org/wikipedia/commons/9/93/Porto_Covo_February_2009-2.jpg)
A tide pool or rock pool is a shallow pool of
seawater
Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appro ...
that forms on the rocky
intertidal
The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of Marine habitat, habitats with var ...
shore
A shore or a shoreline is the fringe of land at the edge of a large body of water, such as an ocean, sea, or lake. In physical oceanography, a shore is the wider fringe that is geologically modified by the action of the body of water past a ...
. Many of these pools exist as separate bodies of
water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
only at
low tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another.
Tide tables can ...
.
Many tide pool
habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
s are home to especially adaptable
animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...
s that have engaged the attention of
naturalists and
marine biologists
Marine biology is the scientific study of the biology of marine life, organisms in the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifie ...
, as well as
philosophical
Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often posed as problems to be studied or resolved. Some ...
essayists:
John Steinbeck
John Ernst Steinbeck Jr. (; February 27, 1902 – December 20, 1968) was an American writer and the 1962 Nobel Prize in Literature winner "for his realistic and imaginative writings, combining as they do sympathetic humor and keen social ...
wrote in ''
The Log from the Sea of Cortez
''The Log from the Sea of Cortez'' is an English-language book written by American author John Steinbeck and published in 1951. It details a six-week (March 11 – April 20) marine specimen-collecting boat expedition he made in 1940 at vario ...
'', "It is advisable to look from the tide pool to the stars and then back to the tide pool."
Zones from shallow to deep
![Tide pools in Santa Cruz from Spray-splash zone to low tide zone](https://upload.wikimedia.org/wikipedia/commons/d/dd/Tide_pools_in_Santa_Cruz_from_Spray-splash_zone_to_low_tide_zone.jpg)
The rocky shoreline exhibits zonation as a feature of the shoreline.
Tidal movements of water creates zonation patterns along rocky shores from high to low-tide. The area above the high-tide mark is the supralittoral zone which is virtually a
terrestrial
Terrestrial refers to things related to land or the planet Earth.
Terrestrial may also refer to:
* Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
environment. The area around the high-tide mark is known as the intertidal fringe. Between the high and low-tide marks is the intertidal or littoral zone. Below the low-tide mark is the sublittoral or subtidal zone.
The presence and abundance of animals and algae vary between zones along the rocky shore due to niche adaptations in response to the varying levels of tidal and solar exposure.
Tide pools exist in the "intertidal zone" (the area within the
tidal range
Tidal range is the difference in height between high tide and low tide. Tides are the rise and fall of sea levels caused by gravitational forces exerted by the Moon and Sun and the rotation of Earth. Tidal range depends on time and location.
...
), which is submerged by the sea at
high tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another.
Tide tables can ...
s and during
storm
A storm is any disturbed state of the natural environment or the atmosphere
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmos ...
s, and may receive spray from
wave action
In fluid dynamics, a wind wave, water wave, or wind-generated water wave, is a surface wave that occurs on the free surface of bodies of water as a result from the wind blowing over the water surface. The contact distance in the direction of t ...
. At other times the rocks may undergo other extreme conditions, baking in the
sun
The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
or exposed to cold winds. Few
organism
In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and ...
s can survive such harsh conditions.
Lichen
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.[barnacle
A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in eros ...]
s live in this zone.
Different
barnacle
A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in eros ...
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
live at very tightly constrained elevations, with tidal conditions precisely determining the exact height of an assemblage relative to sea level.
The intertidal zone is periodically exposed to sun and wind, conditions that can cause barnacles to become
desiccated
Desiccation () is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container.
...
. These animals, therefore, need to be well adapted to water loss. Their
calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...
shells are impermeable, and they possess two
plate
Plate may refer to:
Cooking
* Plate (dishware), a broad, mainly flat vessel commonly used to serve food
* Plates, tableware, dishes or dishware used for setting a table, serving food and dining
* Plate, the content of such a plate (for example: ...
s which they slide across their mouth opening when not feeding. These plates also protect against predation.
High tide zone
The high tide zone is
flood
A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrol ...
ed during each high tide. Organisms must survive wave action,
currents
Currents, Current or The Current may refer to:
Science and technology
* Current (fluid), the flow of a liquid or a gas
** Air current, a flow of air
** Ocean current, a current in the ocean
*** Rip current, a kind of water current
** Current (stre ...
, and exposure to the sun. This zone is predominantly inhabited by
seaweed
Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of '' Rhodophyta'' (red), ''Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such as ...
and
invertebrates
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
, such as
sea anemone
Sea anemones are a group of predation, predatory marine invertebrates of the order (biology), order Actiniaria. Because of their colourful appearance, they are named after the ''Anemone'', a terrestrial flowering plant. Sea anemones are classifi ...
s,
sea star
Starfish or sea stars are Star polygon, star-shaped echinoderms belonging to the class (biology), class Asteroidea (). Common usage frequently finds these names being also applied to brittle star, ophiuroids, which are correctly referred to ...
,
chiton
Chitons () are marine molluscs of varying size in the class Polyplacophora (), formerly known as Amphineura. About 940 extant and 430 fossil species are recognized.
They are also sometimes known as gumboots or sea cradles or coat-of-mail s ...
s,
crab
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...
s,
green algae
The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...
, and
mussels
Mussel () is the common name used for members of several families of bivalve mollusc
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,0 ...
. Marine
algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
provide shelter for
nudibranchs
Nudibranchs () are a group of soft-bodied marine gastropod molluscs which shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have been given colourful nicknames to match, ...
and
hermit crab
Hermit crabs are anomuran decapod crustaceans of the superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an a ...
s. The same waves and currents that make life in the high tide zone difficult bring food to
filter feeder
Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...
s and other intertidal organisms.
Low tide zone
Also called the "lower littoral zone", this area is mostly submerged and is exposed only during unusually low tide.
It often teems with life and has far more marine vegetation, especially seaweeds. There is also greater biodiversity. Organisms in this zone do not have to be as well adapted to drying out and temperature extremes. Low tide zone organisms include
abalone
Abalone ( or ; via Spanish , from Rumsen ''aulón'') is a common name for any of a group of small to very large marine gastropod molluscs in the family (biology), family Haliotidae. Other common name
In biology, a common name of a taxon o ...
, anemones, brown seaweed, chitons, crabs, green algae,
hydroids
Hydroids are a life stage for most animals of the class Hydrozoa, small predators related to jellyfish.
Some hydroids such as the freshwater '' Hydra'' are solitary, with the polyp attached directly to the substrate. When these produce buds ...
,
isopods
Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, an ...
,
limpet
Limpets are a group of aquatic snails that exhibit a conical shell shape (patelliform) and a strong, muscular foot. Limpets are members of the class Gastropoda, but are polyphyletic, meaning the various groups called "limpets" descended indep ...
s, mussels, and sometimes even small
vertebrates
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
such as fish. These creatures can grow to larger sizes because there is more available energy and better water coverage: the water is shallow enough to allow additional sunlight for
photosynthetic
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in c ...
activity, with almost normal levels of
salinity
Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...
. This area is also relatively protected from large
predators
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
because of the wave action and shallow water.
Marine life
Tide pools provide a home for hardy organisms such as
sea stars
Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish ...
,
mussel
Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...
s and
clam
Clam is a common name for several kinds of bivalve molluscs. The word is often applied only to those that are edible and live as infauna, spending most of their lives halfway buried in the sand of the seafloor or riverbeds. Clams have two she ...
s. Inhabitants must be able to deal with a frequently changing
environment
Environment most often refers to:
__NOTOC__
* Natural environment, all living and non-living things occurring naturally
* Biophysical environment, the physical and biological factors along with their chemical interactions that affect an organism or ...
: fluctuations in water
temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer.
Thermometers are calibrated in various temperature scales that historically have relied o ...
, salinity, and
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
content. Hazards include
waves
Waves most often refers to:
*Waves, oscillations accompanied by a transfer of energy that travel through space or mass.
* Wind waves, surface waves that occur on the free surface of bodies of water.
Waves may also refer to:
Music
* Waves (ban ...
, strong
current
Currents, Current or The Current may refer to:
Science and technology
* Current (fluid), the flow of a liquid or a gas
** Air current, a flow of air
** Ocean current, a current in the ocean
*** Rip current, a kind of water current
** Current (stre ...
s, exposure to midday sun and predators.
Waves can dislodge mussels and draw them out to sea.
Gull
Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, m ...
s pick up and drop
sea urchin
Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...
s to break them open. Sea stars prey on mussels and are eaten by gulls themselves.
Black bear
Black bear or Blackbear may refer to:
Animals
* American black bear (''Ursus americanus''), a North American bear species
* Asian black bear (''Ursus thibetanus''), an Asian bear species
Music
* Black Bear (band), a Canadian First Nations group ...
s are known to sometimes feast on intertidal creatures at low tide.
Although tide pool organisms must avoid getting washed away into the
ocean
The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wo ...
, drying up in the sun, or being eaten, they depend on the tide pool's constant changes for food.
Fauna
The
sea anemone
Sea anemones are a group of predation, predatory marine invertebrates of the order (biology), order Actiniaria. Because of their colourful appearance, they are named after the ''Anemone'', a terrestrial flowering plant. Sea anemones are classifi ...
''
Anthopleura elegantissima
The aggregating anemone (''Anthopleura elegantissima''), or clonal anemone, is the most abundant species of sea anemone found on rocky, tide swept shores along the Pacific coast of North America. This cnidarian hosts endosymbiotic algae called ...
'' reproduces clones of itself through a process of longitudinal
fission, in which the animal splits into two parts along its length.
[
]
The sea anemone ''
Anthopleura sola'' often engages in territorial fights. The white tentacles (acrorhagi), which contain stinging cells, are for fighting. The sea anemones sting each other repeatedly until one of them moves.
[
]
Some species of sea stars can
regenerate lost arms. Most species must retain an intact central part of the body to be able to regenerate, but a few can regrow from a single ray. The regeneration of these stars is possible because the vital organs are in the arms.
[
]
Sea Urchins ("
Echinoidia") move around tide pools with tube like feet. Different species of urchin have different colors, and many are seen in tide pools. With
spines, some filled with poison like with "
Toxopnesutes pileolus", that protect them from predators they feed almost undisturbed in tide pools.
Algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
and other microorganism are the food sources that attract them to the tide pools.
Flora
Sea palms (''
Postelsia
''Postelsia palmaeformis'', also known as the sea palm (not to be confused with the southern sea palm) or palm seaweed, is a species of kelp and classified within brown algae. It is the only known species in the genus Postelsia. The sea palm is ...
'') look similar to miniature
palm trees
Palm most commonly refers to:
* Palm of the hand, the central region of the front of the hand
* Palm plants, of family Arecaceae
**List of Arecaceae genera
* Several other plants known as "palm"
Palm or Palms may also refer to:
Music
* Palm (ba ...
. They live in the middle to upper intertidal zones in areas with greater wave action. High wave action may increase nutrient availability and moves the blades of the
thallus
Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms wer ...
, allowing more sunlight to reach the organism so that it can photosynthesize. In addition, the constant wave action removes competitors, such as the mussel species ''
Mytilus californianus''.
Recent studies have shown that ''Postelsia'' grows in greater numbers when such competition exists; a control group with no competition produced fewer offspring than an experimental group with mussels; from this it is thought that the mussels provide protection for the developing
gametophytes
A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the sex ...
.
[
] Alternatively, the mussels may prevent the growth of competing
algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
such as ''
Corallina
''Corallina'' is a genus of red seaweeds with hard, abrasive calcareous skeletons in the family Corallinaceae. They are stiff, branched plants with articulations.
Species
# '' Corallina aberrans'' (Yendo) K.R.Hind & G.W.Saunders
# '' Coralli ...
'' or ''
Halosaccion'', allowing ''Postelsia'' to grow freely after wave action has eliminated the mussels.
[
]
Coralline algae "Corallinales" are predominant features of mid and low intertidal
tide pools
A tide pool or rock pool is a shallow pool of seawater that forms on the rocky intertidal shore. Many of these pools exist as separate bodies of water only at low tide.
Many tide pool habitats are home to especially adaptable animals that ...
.
Calcium carbonate (CaCO
3) takes the form of calcite in their cell walls providing them with a hard outer shell. This shell protects from herbivores and
desiccation
Desiccation () is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container.
...
due to lack of water and evaporation. Many forms of the Coralline algae bring herbivores, such as mollusks "Notoacmea", to the tide pools during high tides, increasing the biomass of the area. Once low tides comes, these herbivores are exposed to carnivores in the areas, fueling the food web.
File:Anthopleura sola is consuming Velella velella.jpg, A large sea anemone ''( Anthopleura sola)'' consuming a "by-the-wind-sailor" ''(Velella velella
''Velella'' is a monospecific genus of hydrozoa in the Porpitidae family. Its only known species is ''Velella velella'', a cosmopolitan free-floating hydrozoan that lives on the surface of the open ocean. It is commonly known by the names sea r ...
),'' a blue hydrozoan
Hydrozoa (hydrozoans; ) are a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specialize ...
File:Postelsia palmaeformis 2.jpg, alt=Photo of speckled rocks, and various irregularly-shaped animals, '' Postelsia palmaeformis'' at low tide in a tide pool
File:Starfishmussel.jpg, alt=Photo of five-legged approximately radially-symmetric animal lying on rock with shelled animal in its mouth, which is in the center of its body, Sea star, ''Pisaster ochraceus
''Pisaster ochraceus'', generally known as the purple sea star, ochre sea star, or ochre starfish, is a common seastar found among the waters of the Pacific Ocean. Identified as a keystone species, ''P. ochraceus'' is considered an important indi ...
'' consuming a mussel in tide pools
File:Close-up of clone war of sea anemones.jpg, Sea anemones, '' Anthopleura sola'' engaged in a battle for territory
See also
*
Intertidal fish
*
List of British Isles rockpool life
The rockpools of the British Isles are a feature of rocky shores and have a particular life of their own. Conditions within them are different from the open sea, as they are exposed to increased sunlight, as well as predation from land-based an ...
*
Rocky shore
A rocky shore is an intertidal area of seacoasts where solid rock predominates. Rocky shores are biologically rich environments, and are a useful "natural laboratory" for studying intertidal ecology and other biological processes. Due to their ...
*
Sydney inter-tidal rock pools
References
External links
Tidal swimming pools in Britain
{{Authority control
Bodies of water
Tides
Marine biology
Coastal geography
Coastal and oceanic landforms