Rocky+Intertidal+Zone+(Heterotrophs)

//** Coastal Ecology Rocky Intertidal Heterotrophs Authors: Ryan Donlon, Travis Costello, and Toby Kim

**//

T able of Contents
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 * Abiotic Description
 * Biotic Components
 * Various heterotrophs
 * Phylums of heterotrophs
 * Intertidal zones
 * Littorina
 * Limpets
 * Barnacles
 * Mussels
 * Sunflower Sea Star
 * Hermit Crab
 * Sea Anenome
 * Chiton
 * Crab
 * Sea Urchin
 * Keystone Species

Rocky intertidal zones are the area of land between the low and high tide water marks. This means that they are the portions of rocky coastline that is periodically covered or exposed by daily tidal changes. Water is constantly washing over the area meaning that they are in a continual state of change. Rocky intertidal zones are characterized by rocky substrates making it possible for tide pools to form.
 * Abiotic Description**

California’s rocky intertidal zones vary in abiotic components depending on where you are on the state’s vast coastline. For example, in Southern California the stone making up the rocky intertidal zone is mostly breccia stone whereas in northern California the stone is predominantly siltstone or sandstone.

Rocky intertidal zones are affected by conditions like desiccation, fluctuating temperatures, changes in salinity, and danger of oxygen depletion. Like most other areas near the California coastline, the temperature can be warm in the daytime and almost will almost invariably be cold at night. As a side effect, the heat can cause desiccation of water and increases in salinity of the tide pools. The heat of the day causes water to evaporate which translates to desiccation. As water disappears, salt remains, meaning a very high salinity level that can kill organisms in the tide pool if the tide is out for too long. Along with salinity levels, when the tide is out for extended periods of time, the oxygen in a tide pool can be used up leaving the water-breathing organisms without a means for air. For this reason, many animals found in tide pools have adapted to both underwater and out-of-water breathing. The pH of tide pools remains mostly constant, changing only as a result of certain types of seaweed, namely Desmerestia, that have low pH levels which then lower that of the tide pools.([|2] )

There are three types of coastline where rocky intertidal zones can be found on the California coast. They are as follows:
 * Protected outer coast: These are semi-sheltered coasts that are protected by the natural shape of the coastline or natural features that shelter it from the direct onset of waves. These features can include offshore reefs or kelp beds.
 * Open coast: This type of coast provides no protection to its organisms. Animals living in open coasts must withstand the full power of the waves. These are often characterized by headlands (i.e. Dana Point) that receive high wave exposure.
 * Bays and Estuaries: Bays and estuaries can be best described as “enclosed bays and sloughs with minor wave exposure. On open coasts animals and plants must withstand the impact of tons of water breaking over them. The organisms of the open coast are characterized by hard bodies and have strong attachment mechanisms. Many of the organisms that occur in sheltered outer coasts or bays are not equipped to take the battering and shearing force of heavy surf. As a result more sheltered areas are often rich in species and distribution, in comparison with the neighboring open coast habitat.” (Ricketts 1985)

Biotic Components Organisms that cannon synthesize its own food and must depend on other complex organic substances for nutrition.([|5] )
 * Heterotrophs

Various heterotrophs
 * Chiton
 * Anemone
 * Coral
 * Navanax (sea slug)
 * Crab
 * Slugs
 * Sponges
 * Flat fish
 * Lobsters
 * Shrimp
 * Limpets
 * Littorina
 * Sponges
 * Stars
 * Sharks
 * Sea Cucumbers
 * Sea Urchin
 * Jelly fish
 * Abalone
 * Flatworms
 * Etc.


 * //Phylums of heterotrophs|//**


 * Cnidaria**
 * Jellyfish
 * Porifera**
 * sponges
 * Platyhelminthes**
 * flatworms
 * Nematoda**
 * roundworms
 * Rotifera**
 * rotifers
 * Mollusca**
 * Clams, snails


 * Annelida**
 * Segmented worms
 * Echinodermata**
 * Se stars, Urchins
 * Arthropoda**
 * Crustaceans, insects
 * Chordata**
 * vertebrates

Zone 1. Uppermost horizon
Characterized by mainly bare rock and sometimes green algae growth, inhabited by hardy, semi terrestrial animals.([|3] )

Zone 2. High Intertidal
Great variety of species, less permanent tide pools, active fauna such as hermit crabs.

Zone 3. Middle Intertidal
Covered during high tides and exposed during most low tides. Densely abundant with life including plants that protect animals from sunlight and provide food.

Zone 4. Low Intertidal
Uncovered only a few times each month and sometimes not at all. Many of the same animals as zone 3 but these are less accustomed to the rhythm of the tides.([|1] )

**//Littorina//** “Shore dwellers” Zone 1 Stay barely close enough to sea to occasionally wet their gills Seen scattered over rocks just above the high tide line possess a distaste for sea water //Littorina keenae// have been kept dry experimentally for 2 months without being damaged They can withstand immersion for several days in freshwater which normally kills all true marine animals A //littorina// was fed to an anemone and after 12-20 hours it lively wandered away with a clean and polished new shell! Uses its radula to eats detritus from rocks and scrape into mussels, oysters and other animals. //Littorina// possess different sexes and can be found copulating any time of the year.([|4] )

Found in zones 1 and 2 //Acmaea, Collosella,// and //Notoacmea// are gastropods (stomache-foot) Phylum Mollusca Limpets appear abundantly, plastered tightly along rocks and can only be removed undamaged by slipping a knife beneath them. Reproductions occurs out at sea as separate sexes of limpets shed egg and sperm freely. Inactive in the daytime but grazes for food at night. Usually returns to its home scar during low tide.
 * //Limpets//**


 * //Barnacles[[image:Picture3.jpg align="right"]]//**

//Balanus gladula// (zone 1) Abundantly seen near the upper limit of Intertidal zone. Dried, dead-looking shells Crustaceans most nearly related to crabs and shrimps than to shelled mollusks These 12mm or less, sharp projecting shells usually clumped together like cells in a honeycomb on sloping or vertical rock faces. Their operculum, a set of hinged plates, are clenched tightly during rain, sun, or snow to protect its inner anatomy. At extreme high tide the barnacle opens its operculum and rhythmically brings in water and small organisms using its brightly colored appendages. It reproduces by brooding eggs and embryos within the shell of the parent and are discharged as free-swimming larvae called nauplii. Its predators include //Pisaster, Nucella,// and //Leptasterias// and competitors include other barnacles and //Mytilus//.


 * //Mussels//** //(Mytiloida)[[image:Picture6.jpg width="267" height="200" align="right"]]//

Mussels are a species of shellfish mostly known for their role in out diets. They are often collected as food by businesses but it is illegal to harvest them without a license.

//Mytiloida// can accumulate and concentrate toxins (domoic acid) produced by minuet organisms, namely dynoflaggelates, that can be harmful to mussel's predators. This is responsible for shellfish poisoning in humans.


 * //Sunflower Sea star[[image:Picture7.jpg width="434" height="334"]]//**

Also known as //picnipodia,// the sunflower sea star can grow up to 12 lbs and is the largest starfish. The species has 5 thousand suction cups on their 25 arms making them also the fastest moving starfish in out ocean waters.. Interestingly, they are cannibalistic in nature and their diet can include other small star fish. Sunflower sea stars reproduce both sexually and asexually.

//**Hermit Crab**// Hermit crabs are a species of decapod crustaceans but contrary to popular belief they are not closely related to crabs. Hermit crabs are a part of //anomera. Like most other crustaceans, they have tough shells but periodically molt, shedding their old shells and obtaining new ones. A //s these "crabs" grow they must abandon their old, smaller shells and find one more fitting to their increasing size.

//** Sea Anemones are part of the family cnidarians. These animals possess an adhesive foot called a pedal disk which they use to move in their tidal homes. Their bodies are shaped like a column with an sac called an oral disk which contains the gastrovascular cavity that functions as both the stomache and the anus. Surrounded by tentacles that are armed with cnidocytes, these animals use their venom as a defense and a way to capture prey.
 * //Sea Anemone//****//(Zoantharia)


 * //Chiton[[image:Picture11.jpg width="223" height="165" align="right"]]//**

Chitons are found in zone 4, the low intertidal zone. They are mostly vegetable eaters but a few species are actively carnivorous. These slow-moving critters are nicknamed sea cradles. As a form of sexual reproduction, the females retain their eggs until the male releases sperm into the water which is then used to fertilize said eggs. Chitons are hidden during the day and feed only at night on drift algae.


 * //Crab pachygrapsus[[image:Picture12.jpg width="268" height="159" align="right"]]//**

//Pachygrapsus// are shore crabs that spend half their time outside the water and the other half in it. They can tolerate wide ranges of temperature and salinity, making them some of the most resilient creatures in this zone. Their diet consists of minute algae (that they gather by scraping them off the rocks with with their Chelae), dead matter, and other small prey.


 * //Sea Urchins//**

Sea urchins are part of the phylum echinoidea. They feed mainly on algae but also feed on other invertabrates such as mussels, sponges, and brittle stars. Their predators include Sea Otters and Wolf Eels. The mouth on sean urchins is centrally located and made up of 5 teeth with a tongue-like structure inside.

//**Keystone Species**//

An example of a keystone species is the sea star. It is one of many species that are considered keystone in the rocky intertidal zone. The sea star is a predator species and feeds mainly on mussels and other prey within the middle intertidal zone. Many different types of seastars can be found in the intertidal zones and all are highly important to the delicate ecosystem.

If something happened the sea star, the mussels would then move to other zones within the environment causing an overpopulation, proving the seastars to be keystone in the rocky intertidal zone.

References 
 * 1) [|http://www.nfb.ca/film/intertidal_zone/]
 * 2) [|http://en.wikipedia.org/wiki/Tidal_zone]
 * 3) [|http://ceres.ca.gov/ceres/calweb/coastal/rocky.html]
 * 4) [|http://www.ocmarineprotection.org/Rocky_Intertidal_Ecosystems.pdf] 
 * 5) http://www.britannica.com/EBchecked/topic/264402/heterotroph