Bioerosion

Bioerosion describes the breakdown of hard ocean substrates – and less often terrestrial substrates – by living organisms. Marine bioerosion can be caused by mollusks, polychaete worms, phoronids, sponges, crustaceans, echinoids, and fish; it can occur on coastlines, on coral reefs, and on ships; 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, and mostly chemical (e.g. by acidic secretions on limestone) or mechanical (e.g. by roots growing into cracks) in nature.

Bioerosion of coral reefs generates the fine and white coral sand characteristic of tropical islands. The coral is converted to sand by internal bioeroders such as algae, fungi, bacteria (microborers) and sponges (Clionaidae), bivalves (including Lithophaga), sipunculans, polychaetes, acrothoracican barnacles and phoronids, generating extremely fine sediment with diameters of 10 to 100 micrometres. External bioeroders include sea urchins (such as Diadema) and chitons. These forces in concert produce a great deal of erosion. Sea urchin erosion of calcium carbonate has been reported in some reefs at annual rates exceeding 20 kg/m2.

Fish also erode coral while eating algae. Parrotfish 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 aragonite 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 record on shells and hardgrounds (Bromley, 1970), with traces of this activity stretching back well into the Precambrian (Taylor & Wilson, 2003). Macrobioerosion, which produces borings visible to the naked eye, shows two distinct evolutionary radiations. One was in the Middle Ordovician (the Ordovician Bioerosion Revolution; see Wilson & Palmer, 2006) and the other in the Jurassic (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).

BoredEncrustedShell
Sponge borings (Entobia) and encrusters on a modern bivalve shell, North Carolina.

Gallery

LibertyBorings

Trypanites borings in an Upper Ordovician hardground, southeastern Indiana; see Wilson and Palmer (2001).

Petroxestes borings Ordovician

Petroxestes borings in an Upper Ordovician hardground, southern Ohio; see Wilson and Palmer (2006).

CarmelHdgd

Gastrochaenolites borings in a Middle Jurassic hardground, southern Utah; see Wilson and Palmer (1994).

FaringdonCobble

Numerous borings in a Cretaceous cobble, Faringdon, England; see Wilson (1986).

JurRockgd01

Cross-section of a Jurassic rockground; borings include Gastrochaenolites (some with boring bivalves in place) and Trypanites; Mendip Hills, England; scale bar = 1 cm.

Teredolites

Teredolites borings in a modern wharf piling; the work of bivalves known as "shipworms".

OrdHdgd03

Ordovician hardground cross-section with Trypanites borings filled with dolomite; southern Ohio.

GastrochaenolitesMatmor

Gastrochaenolites boring in a recrystallized scleractinian coral, Matmor Formation (Middle Jurassic) of southern Israel.

Osprioneides kampto1

Osprioneides borings in a Silurian stromatoporoid from Saaremaa, Estonia; see Vinn, Wilson and Mõtus (2014).

Gnathichnus Cenomanian 020413

Gnathichnus pentax echinoid trace fossil on an oyster from the Cenomanian of Hamakhtesh Hagadol, southern Israel.

Geopetal Structure

Geopetal structure in bivalve boring in coral; bivalve shell visible; Matmor Formation (Middle Jurassic), southern Israel.

Bioeroded brown bodies large

Borings in an Upper Ordovician bryozoan, Bellevue Formation, northern Kentucky; polished cross-section.

See also

  • Biopitting
  • Geomorphology – The scientific study of landforms and the processes that shape them
    • Biogeomorphology – Study of interactions between organisms and the development of landforms
    • Coastal erosion – The loss or displacement of land along the coastline due to the action of waves, currents, tides. wind-driven water, waterborne ice, or other impacts of storms
  • Ocean – A body of water that composes much of a planet's hydrosphere

References

  1. ^ "Terminology for biorelated polymers and applications (IUPAC Recommendations 2012)" (PDF). Pure and Applied Chemistry. 84 (2): 377–410. 2012. doi:10.1351/PAC-REC-10-12-04.

Further reading

External links

Biogeomorphology

Biogeomorphology and ecogeomorphology are the study of interactions between organisms and the development of landforms, and are thus fields of study within geomorphology and ichnology. Organisms affect geomorphic processes in a variety of ways. For example, trees can reduce landslide potential where their roots penetrate to underlying rock, plants and their litter inhibit soil erosion, biochemicals produced by plants accelerate the chemical weathering of bedrock and regolith, and marine animals cause the bioerosion of coral. The study of the interactions between marine biota and coastal landform processes is called coastal biogeomorphology.

Phytogeomorphology is an aspect of biogeomorphology that deals with the narrower subject of how terrain affects plant growth. In recent years a large number of articles have appeared in the literature dealing with how terrain attributes affect crop growth and yield in farm fields, and while they don't use the term phytogeomorphology the dependencies are the same. Precision agriculture models where crop variability is at least partially defined by terrain attributes can be considered as phytogeomorphological precision agriculture.

Biopitting

Biopitting is a geologic phenomenon that occurs when small pits are created in rock as a result of the bioerosion induced by different organisms and/or microorganisms (for example, fungi, bacteria, algae, lichens). This phenomenon occurs when the organisms grow on or near the surface of rocks.

Boring

Boring may refer to:

Something that causes boredom

Calcisiltite

Calcisiltite is a type of limestone that is composed predominantly, more than 50 percent, of detrital (transported) silt-size carbonate grains. These grains consist either of the silt-size particles of ooids, fragments of fossil shells, fragments of older limestones and dolomites, intraclasts, pellets, other carbonate grains, or some combination of these. Calcisiltite is the carbonate equivalent of a siltstone. Calcisiltites can accumulate in a wide variety of coastal, lacustrine, and marine environments. It is typically the product of abrasion and bioerosion.The term calcisiltite was not an original part of the calcilutite, calcarenite and calcirudite classification system for limestones, which Grabau proposed in 1903. Instead, the term calcisiltite was created by Kay in 1951 for limestone consisting predominantly of detrital silt-size, 0.062 to 0.002 mm, grains. As a result, calcisiltite is equivalent to the coarser part of "calcilutite" as it was originally proposed by Grabau and as calcilutite is normally defined and used by geologists. Calcisiltite is the carbonate equivalent of siltstone.

Carbonate hardgrounds

Carbonate hardgrounds are surfaces of synsedimentarily cemented carbonate layers that have been exposed on the seafloor (Wilson and Palmer, 1992). A hardground is essentially, then, a lithified seafloor. Ancient hardgrounds are found in limestone sequences and distinguished from later-lithified sediments by evidence of exposure to normal marine waters. This evidence can consist of encrusting marine organisms (especially bryozoans, oysters, barnacles, cornulitids, hederelloids, microconchids and crinoids), borings of organisms produced through bioerosion, early marine calcite cements, or extensive surfaces mineralized by iron oxides or calcium phosphates (Palmer, 1982; Bodenbender et al., 1989; Vinn and Wilson, 2010; Vinn and Toom, 2015). Modern hardgrounds are usually detected by sounding in shallow water or through remote sensing techniques like side-scan radar.

Carbonate hardgrounds often host a unique fauna and flora adapted to the hard surface. Organisms usually cement themselves to the substrate and live as sessile filter-feeders (Brett and Liddell, 1982). Some bore into the cemented carbonate to make protective domiciles (borings) for filter-feeding. Sometimes hardgrounds are undermined by currents which remove the soft sediment below them, producing shallow cavities and caves which host a cryptic fauna (Palmer and Fürsich, 1974). The evolution of hardground faunas can be traced through the Phanerozoic, from the Cambrian Period to today (Taylor and Wilson, 2003).

Carbonate hardgrounds were most commonly formed during calcite sea intervals in Earth history, which were times of rapid precipitation of low-magnesium calcite and the dissolution of skeletal aragonite (Palmer and Wilson, 2004). The Ordovician-Silurian and the Jurassic-Cretaceous Systems have the most hardgrounds (sometimes hundreds in a single section) and the Permian-Triassic Systems have the least (usually none). This cyclicity in hardground formation is reflected in the evolution of hardground-dwelling communities. There are distinct differences between the Paleozoic and Mesozoic hardground communities: the former are dominated by thick calcitic bryozoans and echinoderms, the latter by oysters and deep bivalve (Gastrochaenolites) and sponge (Entobia) borings (Taylor and Wilson, 2003).

Stratigraphers and sedimentologists often use hardgrounds as marker horizons and as indicators of sedimentary hiatuses and flooding events (Fürsich et al., 1981, 1992; Pope and Read, 1997). Hardgrounds and their faunas can also represent very specific depositional environments such as tidal channels (Wilson et al., 2005) and shallow marine carbonate ramps (Palmer and Palmer, 1977; Malpas et al., 2004)

Coastal biogeomorphology

Since the 1990s, biogeomorphology has developed as an established research field examining the interrelationship between organisms and geomorphic processes in a variety of environments, both marine, and terrestrial. Coastal biogeomorphology looks at the interaction between marine organisms and coastal geomorphic processes. Biogeomorphology is a subdisclipline of geomorphology.

This can include not only microorganisms and plants, but animals as well. These interactions are important factors in the development of certain environments like salt marsh, mangrove and other types of coastal wetlands as well as influencing coastal and shoreline stability.

Coral sand

Coral sand is a collection of 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 component as silt and sand. However, the term "coral" in coral sand is used loosely in this sense to mean limestone of recent biological origin; corals are not the dominant contributors of sand particles to most such deposits. Rather, remnant skeletal fragments of foraminifera, calcareous algae, molluscs, and crustaceans can predominate. Because it is composed of limestone, coral sand is acid-soluble.

Cretaceous

The Cretaceous ( , kri-TAY-shəs) is a geologic period and system that spans from the end of the Jurassic Period 145 million years ago (mya) to the beginning of the Paleogene Period 66 mya. It is the last period of the Mesozoic Era, and the longest period of the Phanerozoic Eon. The Cretaceous Period is usually abbreviated K, for its German translation Kreide (chalk, creta in Latin).

The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites and rudists, while dinosaurs continued to dominate on land. During this time, new groups of mammals and birds, as well as flowering plants, appeared.

The Cretaceous (along with the Mesozoic) ended with the Cretaceous–Paleogene extinction event, a large mass extinction in which many groups, including non-avian dinosaurs, pterosaurs and large marine reptiles died out. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary (K–Pg boundary), a geologic signature associated with the mass extinction which lies between the Mesozoic and Cenozoic eras.

Diadema mexicanum

Diadema mexicanum is a species of long-spined sea urchin belonging to the family Diadematidae. It is native to the Pacific coast of Mexico, Costa Rica, El Salvador, Nicaragua and Panama.

Echinometra viridis

Echinometra viridis, the reef urchin, is a species of sea urchin in the family Echinometridae. It is found on reefs in very shallow parts of the western Atlantic Ocean and the Caribbean Sea.

Mirror website

Mirror websites or mirrors are replicas of other websites. Such websites have different URLs than the original site, but host identical or near-identical content. The main purpose of benign mirrors is often to reduce network traffic, improve access speed, improve availability of the original site, or provide a real-time backup of the original site. Malicious mirror sites can attempt to steal user information, distribute malware, or profit from the content of the original site, among other uses.

Ordovician

The Ordovician () is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.2 million years from the end of the Cambrian Period 485.4 million years ago (Mya) to the start of the Silurian Period 443.8 Mya.The Ordovician, named after the Celtic tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in northern Wales into the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Geological Congress.

Life continued to flourish during the Ordovician as it did in the earlier Cambrian period, although the end of the period was marked by the Ordovician–Silurian extinction events. Invertebrates, namely molluscs and arthropods, dominated the oceans. The Great Ordovician Biodiversification Event considerably increased the diversity of life. Fish, the world's first true vertebrates, continued to evolve, and those with jaws may have first appeared late in the period. Life had yet to diversify on land. About 100 times as many meteorites struck the Earth per year during the Ordovician compared with today.

Oulophyllia crispa

Oulophyllia crispa, sometimes called the intermediate valley coral, is a species of stony coral in the family Merulinidae. It is native to the tropical western and central Indo-Pacific region. Although this coral has a wide range, it is generally uncommon and seems to be decreasing in abundance, and the International Union for Conservation of Nature has rated its conservation status as being "near threatened".

Parrotfish

Parrotfishes are a group of about 95 fish species regarded as a family (Scaridae), or a subfamily (Scarinae) of the wrasses. With about 95 species, this group displays its largest species richness in the Indo-Pacific. They are found in coral reefs, rocky coasts, and seagrass beds, and can play a significant role in bioerosion.

Sclerobiont

Sclerobionts are collectively known as organisms living in or on any kind of hard substrate (Taylor and Wilson, 2003). A few examples of sclerobionts include Entobia borings, Gastrochaenolites borings, Oichnus borings, Talpina borings, serpulids, encrusting oysters, encrusting foraminiferans, Stomatopora bryozoans, and “Berenicea” bryozoans.

Sponge

Sponges, the members of the phylum Porifera (; meaning "pore bearer"), are a basal Metazoa (animal) clade as a sister of the Diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells. The branch of zoology that studies sponges is known as spongiology.

Sponges have unspecialized cells that can transform into other types and that often migrate between the main cell layers and the mesohyl in the process. Sponges do not have nervous, digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponges were first to branch off the evolutionary tree from the common ancestor of all animals, making them the sister group of all other animals.

Trace fossil

A trace fossil, also ichnofossil ( ; from Greek: ἴχνος ikhnos "trace, track"), is a geological record of biological activity. Ichnology is the study of such traces, and is the work of ichnologists. Trace fossils may consist of impressions made on or in the substrate by an organism: for example, burrows, borings (bioerosion), urolites (erosion caused by evacuation of liquid wastes), footprints and feeding marks, and root cavities. The term in its broadest sense also includes the remains of other organic material produced by an organism—for example coprolites (fossilized droppings) or chemical markers—or sedimentological structures produced by biological means—for example, stromatolites. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or mineralization.

Sedimentary structures, for example those produced by empty shells rolling along the sea floor, are not produced through the behaviour of an organism and not considered trace fossils.

The study of traces - ichnology - divides into paleoichnology, or the study of trace fossils, and neoichnology, the study of modern traces. Ichnological science offers many challenges, as most traces reflect the behaviour—not the biological affinity—of their makers. Accordingly, researchers classify trace fossils into form genera, based on their appearance and on the implied behaviour, or ethology, of their makers.

Trepostomata

Trepostomata (the trepostomates) is an extinct bryozoan order in the class Stenolaemata.

Trypanites

Trypanites is a narrow, cylindrical, unbranched boring which is one of the most common trace fossils in hard substrates such as rocks, carbonate hardgrounds and shells (Bromley, 1972). It appears first in the Lower Cambrian (James et al., 1977), was very prominent in the Ordovician Bioerosion Revolution (Wilson and Palmer, 2006), and is still commonly formed today. Trypanites is almost always found in calcareous substrates, most likely because the excavating organism used an acid or other chemical agent to dissolve the calcium carbonate (Taylor and Wilson, 2003). Trypanites is common in the Ordovician and Silurian hardgrounds of Baltica (Vinn et al. 2015).

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