Bioerosion describes the erosion

Erosion

Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 of hard ocean substrate

Substrate (marine biology)

Stream substrate is the material that rests at the bottom of a stream. There are several classification guides. One is:*Mud – silt and clay.*Sand – Particles between 0.06 and 2 mm in diameter.*Granule – Between 2 and 4 mm in diameter....

s – and less often terrestrial substrates – by living organisms. Marine bioerosion can be caused by mollusks, polychaete worms

Polychaete

The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...

, phoronid

Phoronid

Phoronids are a phylum of marine animals that filter-feed with a lophophore , and build upright tubes of chitin to support and protect their soft bodies. They live in all the oceans and seas including the Arctic Ocean but excluding the Antarctic Ocean, and between the intertidal zone and about...

s, sponge

Sea sponge

Sponges are animals of the phylum Porifera . Their bodies consist of jelly-like mesohyl sandwiched between two thin layers of cells. While all animals have unspecialized cells that can transform into specialized cells, sponges are unique in having some specialized cells, but can also have...

s, crustaceans, echinoid

Echinoderm

Echinoderms are a phylum of marine animals. Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone....

s, and fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

; it can occur on coastlines, on coral reef

Coral reef

Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...

s, and on ship

Ship

Since the end of the age of sail a ship has been any large buoyant marine vessel. Ships are generally distinguished from boats based on size and cargo or passenger capacity. Ships are used on lakes, seas, and rivers for a variety of activities, such as the transport of people or goods, fishing,...

s; its mechanisms include biotic boring, drilling, rasping, and scraping. On dry land, bioerosion is typically performed by pioneer plants or plant-like organisms such as lichen

Lichen

Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...

, and mostly chemical (e.g. by acidic secretions on limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

) or mechanical (e.g. by root

Root

In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

s growing into cracks) in nature.

Bioerosion of coral reefs generates the fine and white coral sand

Coral sand

Coral sand is sand of particles originating in tropical and sub-tropical marine environments from bioerosion of limestone skeletal material of marine organisms. One example of this process is that of parrot fishes which bite off pieces of coral, digest the living tissue, and excrete the inorganic...

 characteristic of tropical islands. The coral is converted to sand by internal bioeroders such as algae

Algae

Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...

, fungi, bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 (microborers) and sponge

Sea sponge

Sponges are animals of the phylum Porifera . Their bodies consist of jelly-like mesohyl sandwiched between two thin layers of cells. While all animals have unspecialized cells that can transform into specialized cells, sponges are unique in having some specialized cells, but can also have...

s (Clionaidae), bivalves (including Lithophaga

Lithophaga

Lithophaga, the date mussels, are a genus of medium-sized marine bivalve molluscs in the family Mytilidae.The shells of species in this genus are long and narrow with parallel sides. The animals bore into stone or coral rock with the help of pallial gland secretions, hence the systematic name...

), sipunculans, polychaetes, acrothoracican barnacles

Rogerella

Rogerella is a small pouch-shaped boring with a slit-like aperture currently produced by acrothoracican barnacles. These crustaceans extrude their legs upwards through the opening for filter-feeding...

 and phoronid

Phoronid

Phoronids are a phylum of marine animals that filter-feed with a lophophore , and build upright tubes of chitin to support and protect their soft bodies. They live in all the oceans and seas including the Arctic Ocean but excluding the Antarctic Ocean, and between the intertidal zone and about...

s, generating extremely fine sediment with diameters of 10 to 100 micrometres. External bioeroders include sea urchin

Sea urchin

Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...

s (such as Diadema) and chiton

Chiton

Chitons are small to large, primitive marine molluscs in the class Polyplacophora.There are 900 to 1,000 extant species of chitons in the class, which was formerly known as Amphineura....

s. These forces in concert produce a great deal of erosion. Sea urchin

Sea urchin

Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...

 erosion of calcium carbonate

Calcium carbonate

Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...

 has been reported in some reefs at annual rates exceeding 20 kg/m².

Fish also erode coral while eating algae

Algae

Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...

. Parrotfish

Parrotfish

Parrotfishes are a group of fishes that traditionally had been considered a family , but now often are considered a subfamily of the wrasses. They are found in relatively shallow tropical and subtropical oceans throughout the world, but with the largest species richness in the Indo-Pacific...

 cause a great deal of bioerosion using well developed jaw muscles, tooth armature, and a pharyngeal mill, to grind ingested material into sand-sized particles. Bioerosion of coral reef

Coral reef

Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...

 aragonite

Aragonite

Aragonite is a carbonate mineral, one of the two common, naturally occurring, crystal forms of calcium carbonate, CaCO3...

 by parrotfish can range from 1017.7±186.3 kg/yr (0.41±0.07 m³/yr) for Chlorurus gibbus and 23.6±3.4 kg/yr (9.7 10-³±1.3 10-³ m²/yr) for Chlorurus sordidus (Bellwood, 1995).

Bioerosion is also well known in the fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 record on shells and hardgrounds (Bromley, 1970), with traces of this activity stretching back well into the Precambrian

Precambrian

The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...

 (Taylor & Wilson, 2003). Macrobioerosion, which produces borings visible to the naked eye, shows two distinct evolutionary radiation

Evolutionary radiation

An evolutionary radiation is an increase in taxonomic diversity or morphological disparity, due to adaptive change or the opening of ecospace. Radiations may affect one clade or many, and be rapid or gradual; where they are rapid, and driven by a single lineage's adaptation to their environment,...

s. One was in the Middle Ordovician

Ordovician

The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...

 (the Ordovician Bioerosion Revolution; see Wilson & Palmer, 2006) and the other in the Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

 (see Taylor & Wilson, 2003; Bromley, 2004; Wilson, 2007). Microbioerosion also has a long fossil record and its own radiations (see Glaub & Vogel, 2004; Glaub et al., 2007).

External links

• http://www3.wooster.edu/geology/Bioerosion/Bioerosion.htmlBioerosion Website at The College of Wooster
  The College of Wooster
  The College of Wooster is a private liberal arts college primarily known for its Independent study program. It has roughly 2,000 students and is located in Wooster, Wayne County, Ohio, United States . Founded in 1866 by the Presbyterian church as the University of Wooster, it was from its creation...
  
  ]