Gribble
Encyclopedia
A gribble is any of about 56 species of marine isopod
from the family Limnoriidae. They are mostly pale white and small (1–4 mm or 0.0393700787401575–0.15748031496063 long) crustacean
s, although Limnoria stephenseni from subantarctic
waters can reach 10 mm (0.393700787401575 in).
and seagrass
borers, as well as wood borers. Those gribbles able to bore into living marine plants are thought to have evolved from a wood (dead plant) boring species.
of wood is digested, most likely with the aid of cellulase
s produced by the gribbles themselves. The most destructive species are Limnoria lignorum, L. tripunctata and L. quadripunctata. Due to dispersal while inhabiting wooden ships, it is uncertain where these three mentioned species originated. Limnoriidae are second only to the Teredinidae in the amount of destruction caused to marine timber structures such as jetties and piers. L. tripunctata is unusually tolerant of creosote
, a preservative often used to protect timber piles, due to symbiosis with creosote-degrading bacteria. Gribbles bore the surface layers of wood, unlike the Teredinidae which attack more deeply. Their burrows are 1–2 mm diameter, may be several centimetres long, and have the burrow’s roof punctured with a series of smaller ventilation holes. Attacked wood can become spongy and friable.
Gribbles play an ecologically important role, by helping to degrade and recycle driftwood. Most seaweed boring gribbles attack holdfasts and their activities can cause the seaweed to come adrift especially during storms.
For defence, gribbles can jam themselves within their burrows using their uropods and block the tunnel with their rear disc-shaped segment, the pleotelson.
A number of crustaceans have evolved as commensals with Limnoriidae. Chelura are amphipods
that inhabit the more severely attacked regions of gribble-attacked wood. Donsiella are tiny copepod
s that inhabit the brood pouch and body of Limnoriidae.
, such as wood or straw, in a sustainable way. This could then be used to produce alternative fuels. "Enzymes produced by the tiny creatures are able to break down woody cellulose and turn it into energy-rich sugars meaning that gribble could convert wood and straw into liquid biofuel."
Isopoda
Isopods are an order of peracarid crustaceans, including familiar animals such as woodlice and pill bugs. The name Isopoda derives from the Greek roots and...
from the family Limnoriidae. They are mostly pale white and small (1–4 mm or 0.0393700787401575–0.15748031496063 long) crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, although Limnoria stephenseni from subantarctic
Subantarctic
The Subantarctic is a region in the southern hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° – 60° south of the Equator. The subantarctic region includes many islands in the southern parts of the Indian Ocean, Atlantic Ocean and...
waters can reach 10 mm (0.393700787401575 in).
Classification
The term "gribble" was originally assigned to the wood-boring species, especially the first species described from Norway by Jens Rathke in 1799, Limnoria lignorum. The Limnoriidae are now known to include seaweedSeaweed
Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...
and seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
borers, as well as wood borers. Those gribbles able to bore into living marine plants are thought to have evolved from a wood (dead plant) boring species.
Ecology
Gribbles bore into wood and plant material for ingestion as food. The celluloseCellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
of wood is digested, most likely with the aid of cellulase
Cellulase
400px|thumb|right|alt = Colored dice with checkered background|Ribbon representation of the Streptomyces lividans beta-1,4-endoglucanase catalytic domain - an example from the family 12 glycoside hydrolases...
s produced by the gribbles themselves. The most destructive species are Limnoria lignorum, L. tripunctata and L. quadripunctata. Due to dispersal while inhabiting wooden ships, it is uncertain where these three mentioned species originated. Limnoriidae are second only to the Teredinidae in the amount of destruction caused to marine timber structures such as jetties and piers. L. tripunctata is unusually tolerant of creosote
Creosote
Creosote is the portion of chemical products obtained by the distillation of a tar that remains heavier than water, notably useful for its anti-septic and preservative properties...
, a preservative often used to protect timber piles, due to symbiosis with creosote-degrading bacteria. Gribbles bore the surface layers of wood, unlike the Teredinidae which attack more deeply. Their burrows are 1–2 mm diameter, may be several centimetres long, and have the burrow’s roof punctured with a series of smaller ventilation holes. Attacked wood can become spongy and friable.
Gribbles play an ecologically important role, by helping to degrade and recycle driftwood. Most seaweed boring gribbles attack holdfasts and their activities can cause the seaweed to come adrift especially during storms.
For defence, gribbles can jam themselves within their burrows using their uropods and block the tunnel with their rear disc-shaped segment, the pleotelson.
A number of crustaceans have evolved as commensals with Limnoriidae. Chelura are amphipods
Amphipoda
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. The name amphipoda means "different-footed", and refers to the different forms of appendages, unlike isopods, where all the legs are alike. Of the 7,000 species, 5,500 are classified...
that inhabit the more severely attacked regions of gribble-attacked wood. Donsiella are tiny copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s that inhabit the brood pouch and body of Limnoriidae.
As a source of biofuel
It has been suggested that the enzymes used by Limnoriidae to break down wood may be useful for producing sugar from non-food biomassBiomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
, such as wood or straw, in a sustainable way. This could then be used to produce alternative fuels. "Enzymes produced by the tiny creatures are able to break down woody cellulose and turn it into energy-rich sugars meaning that gribble could convert wood and straw into liquid biofuel."