Osedax

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Osedax
Temporal range: Albian–Present
Osedax roseus.jpg
Osedax roseus
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Annelida
Clade: Pleistoannelida
Subclass: Sedentaria
Order: Sabellida
Family: Siboglinidae
Genus: Osedax
Rouse et al., 2004 [1]
Species

See text.

Osedax is a genus of deep-sea siboglinid polychaetes, commonly called boneworms, zombie worms, or bone-eating worms. Osedax is Latin for "bone-eater". The name alludes to how the worms bore into the bones of whale carcasses to reach enclosed lipids, on which they rely for sustenance. They utilize specialized root tissues for bone-boring. It is possible that multiple species of Osedax reside in the same bone. [2] Osedax worms are also known to feed on the collagen itself by making holes in the whale's skeletal structure. These holes can also serve as a form of protection from nearby predators.

Contents

Scientists from the Monterey Bay Aquarium Research Institute using the submarine ROV Tiburon first discovered the genus in Monterey Bay, California, in February 2002. The worms were found living on the bones of a decaying gray whale in the Monterey Canyon, at a depth of 2,893 m (9,491 ft).

Anatomy and physiology

Lacking stomach and mouth, Osedax rely on symbiotic species of bacteria that aid in the digestion of whale proteins and lipids and release nutrients that the worms can absorb. [3] Osedax have colorful feathery plumes that also act as gills and unusual root-like structures that absorb nutrients. The Osedax secrete acid (rather than rely on teeth) to bore into bone to access the nutrients. [4] High concentrations of carbonic anhydrase are found in the roots of Osedax. This serves as evidence of a common bioerosion mechanism in which secreted acid is produced by anaerobic respiration. This process works with a demineralization mechanism in which oxygen is carried from seawater to the roots and HCO3- is secreted into the seawater. [5] Between 50 and 100 microscopic dwarf males live inside the tube surrounding a single female and never develop past the larval stage. Osedax can grow up to 3 inches long.

Through the use of X-ray CT technology, scans showed that borings made by Osedax mucofloris were hemi-ellipsoidal in shape, flat at the top, and a bit rounded at the deepest point within the bone. The borings' surface area to volume ratio decreases as the borings become larger due to the hemi-ellipsoidal shape. Boring depths varied depending on which specific bone was colonized by the O. mucofloris. Higher boring depths were found in radius bone compared to the ulna and vertebrae. [6]

Osedax worms have different regions such as a trunk region, ovisac region, and root region. The epidermis also plays key roles in bone deterioration and nutrient uptake. This process of bone deterioration occurs through a symbiotic relationship with an endosymbiotic bacteria. [7] The cells in the epidermis of the Osedax root region are responsible for the secretion of digestive enzymes. The epidermis also has an expanded microvillus border which causes the Osedax worm to have a greater surface area. [7]

Osedax roots are covered by a mucus sheath that helps protect the worm's trunk. Some studies support the theory that this sheath plays a role in dissolving the bone. This sheath could also play an important role in reducing the damage to Osedax skin by absorbing harmful acid. Another potential function of the mucus sheath is that it could inhibit the breakdown of the worm's bone matrix. This is significant because the bone matrix is integral in maintaining the worm's position while in direct contact with a bone. [5]

Reproduction

Female Osedax worms have been observed spawning both in the wild and in laboratory aquaria (Rouse et al., 2009). Osedax rubiplumus can spawn hundreds of oocytes at a time. They are already fertilized when they're released from the female worm. The worms' endosymbionts, species of bacteria in the order Oceanospirillales, were not observed in the spawned oocytes, which suggests that they are acquired after the worms settle on the bones. [8] In the adult, the bacteria are localised in the root-like structures that grow into the whale bone. [9] [10] This worm appears to be highly fecund and reproduces continuously. This may help explain why Osedax is such a diverse genus, despite the rarity of whale falls in the ocean.

Male Osedax are microscopic dwarfs that live as "harems" inside the lumen of the gelatinous tube that surrounds each female. An individual female can house hundreds of these males in her tube. [11] [12]

Following its discovery in 2002 by researchers at the Monterey Bay Aquarium Research Institute, the genus was announced in Science in 2004. [1]

In late 2005, an experiment by Swedish marine biologists resulted in the discovery of a species of the worm in the North Sea off the west coast of Sweden. In the experiment, a minke whale carcass that had been washed ashore had been sunk to a depth of 120 m (390 ft) and monitored for several months. Biologists were surprised to find that, unlike the previous discoveries, the new species, colloquially known as "bone-eating snot flower" after its scientific name (Osedax mucofloris), lived in relatively shallow waters.

In November 2009, researchers reported finding as many as 15 species of boneworms living in Monterey Bay on the California coast. [13]

Niche

Osedax frankpressi Osedax frankpressi.jpg
Osedax frankpressi

The role of Osedax in the degradation of marine vertebrate remains controversial. Some scientists [14] think that Osedax is a specialist on whalebones while others think that it is more of a generalist. [15] [16] This controversy is due to a biogeographic paradox: despite the rarity and ephemeral nature of whale falls, Osedax has a broad biogeographic range and is surprisingly diverse. One hypothesis advanced to explain this paradox is that Osedax are able to colonize a variety of vertebrate remains besides whalebones. This hypothesis is supported by an experiment involving cow bones suspended above the sea floor. A variety of Osedax species successfully colonized these bones. Osedax have also been observed colonizing terrestrial mammal bones mixed in with galley waste from a surface vessel. Other scientists have countered this hypothesis by pointing out how the cow bone experiment does not match any natural habitat and also the low probability of terrestrial mammal bones arriving at the ocean floor in significant quantities. They also point out other cases of food falls in which the remains disappeared too swiftly for Osedax colonization and the lack of any observed colonization in similar cases. The true role of Osedax in the degradation of marine vertebrate remains is important to marine vertebrate taphonomy. Burrows closely similar to those made by Osedax species have been found in the bones of ancient marine birds and plesiosaurs, suggesting that the genus may once have had a wider range of foods. [17] [18] [19] In a study of the boring morphological diversity of Osedax, it was shown that the species difference of bone-boring is highly variable; within the same species, the boring morphology is only consistent in a particular bone, but not consistent in different bones. It was also suggested that multiple species of Osedax can co-exist in the same bone and in an incomplete spatial niche differentiation. [2]

The function of Osedax and their borings welcome other species such as Stephonyx amphipods, Paralomis crabs, and Rubyspira gastropods. As Osedax worms break down bone and lipid layers, fauna take advantage and colonize these bone matrices. Overall, the borings made by Osedax have shown to enhance biodiversity and the worms should, therefore, be considered ecosystem engineers. The downside of the deterioration caused by Osedax is that it speeds up the process of erosion, therefore only allowing this new fauna their new habitats for a temporary period. [20]

Evolution

The oldest trace fossils on bones characteristic of Osedax are from a plesiosaur humerus from the Cambridge Greensand, England, likely reworked from late Albian (~100 million years old) sediments and a rib and costal plate from a sea turtle found in Cenomanian (100-93 million years ago) aged sediments of the Chalk Group, England. Osedax likely persisted on the bones of sea turtles after the extinction of most large marine reptiles at the end of the Cretaceous. [21] Osedax have the generalist ability to feed on different vertebrates (fishes, marine birds, whale bones). [22]

In terms of evolutionary history research, the Osedax could have had negative impact in preserving fossil record because its appearance at the shelf-depth combined with its ability to efficiently break down marine vertebrates skeletons. [21]

Species

Osedax rubiplumus Osedax rubiplumus.jpg
Osedax rubiplumus

Selected species: [23] [24] [25] [26]

Related Research Articles

<span class="mw-page-title-main">Siboglinidae</span> Family of annelid worms

Siboglinidae is a family of polychaete annelid worms whose members made up the former phyla Pogonophora and Vestimentifera. The family is composed of around 100 species of vermiform creatures which live in thin tubes buried in sediment (Pogonophora) or in tubes attached to hard substratum (Vestimentifera) at ocean depths ranging from 100 to 10,000 m. They can also be found in association with hydrothermal vents, methane seeps, sunken plant material, and whale carcasses.

<span class="mw-page-title-main">Marine worm</span>

Any worm that lives in a marine environment is considered a water worm. Marine worms are found in several different phyla, including the Platyhelminthes, Nematoda, Annelida, Chaetognatha, Hemichordata, and Phoronida. For a list of marine animals that have been called "sea worms", see sea worm.

<span class="mw-page-title-main">Whale fall</span> Whale carcass falling to the ocean floor

A whale fall occurs when the carcass of a whale has fallen onto the ocean floor at a depth greater than 1,000 m (3,300 ft), in the bathyal or abyssal zones. On the sea floor, these carcasses can create complex localized ecosystems that supply sustenance to deep-sea organisms for decades. This is unlike in shallower waters, where a whale carcass will be consumed by scavengers over a relatively short period of time. Whale falls were first observed in the late 1970s with the development of deep-sea robotic exploration. Since then, several natural and experimental whale falls have been monitored through the use of observations from submersibles and remotely operated underwater vehicles (ROVs) in order to understand patterns of ecological succession on the deep seafloor.

Osedax mucofloris is a species of bathypelagic Polychaetes that is reported to sustain itself on the bones of dead whales. Translated from the mixed Greek and Latin used in scientific names, "Osedax mucofloris" literally means "snot-flower bone-eater", though the less-accurate "bone-eating snot-flower worm" seems to be the form actually used. The species is found in North East Atlantic where it is abundant.

<span class="mw-page-title-main">Trophosome</span> Organ containing endosymbionts

A trophosome is a highly vascularised organ found in some animals that houses symbiotic bacteria that provide food for their host. Trophosomes are contained by the coelom of the vestimentiferan tube worms and in the body of symbiotic flatworms of the genus Paracatenula.

<i>Osedax roseus</i> Species of annelid worm

Osedax roseus is a species of bathypelagic polychaete worm that lives at abyssal depths and is able to sustain itself on the bones of dead whales. The species is found in the North East Pacific.

<i>Osedax rubiplumus</i> Species of annelid

Osedax rubiplumus is a species of bathypelagic Polychaetes that is reported to sustain itself on the bones of dead whales.

<i>Osedax frankpressi</i> Species of annelid worm

Osedax frankpressi is a species of bathypelagic polychaete worm that lives on the seabed and sustains itself on the bones of dead whales. It can be found in the East North Pacific Ocean. The specific epithet is named in honor of Frank Press "for his distinguished service to science".

Osedax japonicus is a species of bathypelagic polychaete tube worm that lives at great depths on the seabed and is able to sustain itself on the bones of a dead whale. It was first described in 2006 from a sunken sperm whale carcase near Kyushu, Japan.

Osedax priapus is a species of bathypelagic annelid polychaete worms that consume the nutrients inside the bones of dead whales or other vertebrates.

Ophryotrocha scutellus, is a species of polychaete worm. Live observation of this species in aquarium experiments indicate a bacterial diet. O. scutellus is named after the Latin scutella for “saucer”, due to its flattened disc-like head. Ophryotrocha scutellus has a dorsoventrally rounded and flattened prostomium, similar to O. platykephale, from which this species differs in jaw morphology, the form of its parapodia and the absence of branchiae.

<i>Rubyspira</i> Genus of gastropods

Rubyspira is a genus of deep water sea snails, marine gastropod mollusks unclassified in the family within the superfamily Abyssochrysoidea.

Ophryotrocha longicollaris is a species of polychaete worm, first found on deep sea whale fall and wood fall habitats in the north-east Pacific, off the southern Californian coast. This species and Ophryotrocha magnadentata are sister species; together with O. nauarchus and O. flabella, it falls in a clade including O. globopalpata and Exallopus jumarsi from the shallow North Atlantic.

Ophryotrocha magnadentata is a species of polychaete worm, first found on deep sea whale fall and wood fall habitats in the north-east Pacific, off the southern Californian coast. This species and Ophryotrocha longicollaris are sister species; together with O. nauarchus and O. flabella, it falls in a clade including O. globopalpata and Exallopus jumarsi from the shallow North Atlantic.

Ophryotrocha nauarchus is a species of polychaete worm, first found on deep sea whale fall and wood fall habitats in the north-east Pacific, off the southern Californian coast. The species is sexually dimorphic, males having appendages on their first chaetiger.

Ophryotrocha flabella is a species of polychaete worm, first found on deep sea whale fall and wood fall habitats in the north-east Pacific, off the southern Californian coast. It is similar to Ophryotrocha globopalpata, possessing some morphological differences, although genetic divergence is low between them.

Ophryotrocha langstrumpae is a species of polychaete worm, first found on deep sea whale fall and wood fall habitats in the north-east Pacific, off the southern Californian coast. It is closely related to Ophryotrocha scutellus and Ophryotrocha batillus.

Ophryotrocha batillus is a species of polychaete worm, first found on deep sea whale fall and wood fall habitats in the north-east Pacific, off the southern Californian coast. It is very similar to Ophryotrocha scutellus, yet differs from the latter genetically.

Oligobrachia is a genus in the family Siboglinidae, commonly known as beard worms. These beard worms are typically found at spreading centers, hydrothermal vents, and undersea volcanoes. The siboglinidae are annelids which can be found buried in sediments. Beard worms do not necessarily exist at one specific part of the world's oceans, however, they are spread out all over the ocean floors as long as the surrounding environment is similar; these are known as metapopulations. Most commonly, these organisms are found at the bottom of the ocean floor, whether it be at a depth of roughly 25 meters or hundreds of meters. Oligobrachia can typically be found near hydrothermal vents and methane seeps. An important characteristic of this genus is that it lacks a mouth and gut. Therefore, it relies on symbiotic bacteria to provide the host organism with energy to survive. The majority of oligobrachia that have been observed have been found in the Arctic and other high-latitude areas of the world's oceans.

Frenulata, "beard worms", is a clade of Siboglinidae, "tube worms". They are one of four lineages with numerous species. They may be the most basal clade in the family. Despite being the first tube worms to be encountered and described, they remain the least studied group. This is because of their slender shape, they often get destroyed as a result of being caught as bycatch or poor preservation. They are found primarily in deep, muddy sediments, cold seeps, and anoxic firth sediments.

References

  1. 1 2 G. W. Rouse; S. K. Goffredi & R. C. Vrijenhoek (2004). "Osedax: Bone-Eating Marine Worms with Dwarf Males". Science. 305 (5684): 668–671. Bibcode:2004Sci...305..668R. doi:10.1126/science.1098650. PMID   15286372. S2CID   34883310.
  2. 1 2 Higgs, Nicholas D.; Glover, Adrian G.; Dahlgren, Thomas G.; Smith, Craig R.; Fujiwara, Yoshihiro; Pradillon, Florence; Johnson, Shannon B.; Vrijenhoek, Robert C.; Little, Crispin T. S. (2014). "The morphological diversity of Osedax worm borings (Annelida: Siboglinidae)" (PDF). Journal of the Marine Biological Association of the United Kingdom. 94 (7): 1429–1439. Bibcode:2014JMBUK..94.1429H. doi:10.1017/S0025315414000770. S2CID   52246559.
  3. ↑ Marlow, Jeffrey (February 18, 2019). "A Whale's Afterlife". The New Yorker. ISSN   0028-792X . Retrieved February 20, 2019.
  4. ↑ "Bone-eating 'zombie' worms drill with acid". BBC News.
  5. 1 2 Tresguerres, Martin; Katz, Sigrid; Rouse, Greg W. (June 22, 2013). "How to get into bones: proton pump and carbonic anhydrase in Osedax boneworms". Proceedings of the Royal Society B: Biological Sciences. 280 (1761): 20130625. doi:10.1098/rspb.2013.0625. PMC   3652447 . PMID   23760644.
  6. ↑ Higgs, Nicholas D.; Glover, Adrian G.; Dahlgren, Thomas G.; Little, Crispin T. S. (December 2011). "Bone-Boring Worms: Characterizing the Morphology, Rate, and Method of Bioerosion by Osedax mucofloris (Annelida, Siboglinidae)". The Biological Bulletin. 221 (3): 307–316. doi:10.1086/bblv221n3p307. ISSN   0006-3185. PMID   22186919. S2CID   32725146.
  7. 1 2 Katz, Sigrid; Klepal, Waltraud; Bright, Monika (October 2010). "The skin of Osedax (Siboglinidae, Annelida): An ultrastructural investigation of its epidermis". Journal of Morphology. 271 (10): 1272–1280. doi:10.1002/jmor.10873. PMID   20672365. S2CID   10697873.
  8. ↑ G. W. Rouse; N. G. Wilson; S. K. Goffredi; S. B. Johnson; T. Smart; C. Widmer; C. M. Young & R. C. Vrijenhoek (2009). "Spawning and development in Osedax boneworms (Siboglinidae, Annelida)". Marine Biology. 156 (3): 395–405. Bibcode:2009MarBi.156..395R. doi:10.1007/s00227-008-1091-z. S2CID   84177994.
  9. ↑ Goffredi, S. K.; Orphan, V. J.; Rouse, G. W.; Jahnke, L.; Embaye, T.; Turk, K.; Lee, R.; Vrijenhoek, R. C. (2005). "Evolutionary innovation: a bone-eating marine symbiosis". Environmental Microbiology. 7 (9): 1369–1378. Bibcode:2005EnvMi...7.1369G. doi:10.1111/j.1462-2920.2005.00824.x. PMID   16104860.
  10. ↑ Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press.
  11. ↑ Rouse, G. W.; Worsaae, K.; Johnson, S.; Jones, W. J.; Vrijenhoek, R. C. (2008). "Acquisition of dwarf male 'harems' by recently settled females of Osedax roseus n. sp. (Siboglinidae; Annelida)" (PDF). Biological Bulletin. 214 (1): 67–82. doi:10.2307/25066661. JSTOR   25066661. PMID   18258777. S2CID   8457281.
  12. ↑ Vrijenhoek, R. C.; Johnson, S.; Rouse, G. W. (2008). "Bone-eating Osedax females and their 'harems' of dwarf males are recruited from a common larval pool". Molecular Ecology. 17 (20): 4535–4544. Bibcode:2008MolEc..17.4535V. doi:10.1111/j.1365-294X.2008.03937.x. PMID   18986498. S2CID   19247165.
  13. ↑ Vrijenhoek, R. C.; Johnson, S. B.; Rouse, G. W. (2009). "A remarkable diversity of bone-eating worms (Osedax; Siboglinidae; Annelida)". BMC Biology. 7: 74. doi: 10.1186/1741-7007-7-74 . PMC   2780999 . PMID   19903327.
  14. ↑ Glover et al. 2005; Dahlgren et al. 2006; Fujijura et al. 2006
  15. ↑ Jones et al. 2008
  16. ↑ Rouse, GW; Goffredi, SK; Johnson, SB; Vrijenhoek, RC (October 23, 2011). "Not whale-fall specialists, Osedax worms also consume fishbones". Biology Letters. 7 (5): 736–739. doi:10.1098/rsbl.2011.0202. PMC   3169056 . PMID   21490008.
  17. ↑ Kaplan, Matt (2010). "Bone-boring worm once had a taste for birds. Osedax worms might have had a more-rounded diet 30 million years ago". Nature. doi:10.1038/news.2010.651.
  18. ↑ Kiel, Steffen; Kahl, Wolf-Achim; Goedert, James L. (2010). "Osedax borings in fossil marine bird bones". Naturwissenschaften. 98 (1): 51–55. doi:10.1007/s00114-010-0740-5. PMC   3018246 . PMID   21103978.
  19. ↑ "Zombie worms ate plesiosaur bones". BBC News. April 15, 2015.
  20. ↑ Alfaro-Lucas, Joan M.; Shimabukuro, Maurício; Ferreira, Giulia D.; Kitazato, Hiroshi; Fujiwara, Yoshihiro; Sumida, Paulo Y.G. (December 2017). "Bone-eating Osedax worms (Annelida: Siboglinidae) regulate biodiversity of deep-sea whale-fall communities". Deep Sea Research Part II: Topical Studies in Oceanography. 146: 4–12. Bibcode:2017DSRII.146....4A. doi:10.1016/j.dsr2.2017.04.011.
  21. 1 2 Danise, Silvia; Higgs, Nicholas D. (April 2015). "Bone-eating Osedax worms lived on Mesozoic marine reptile deadfalls". Biology Letters. 11 (4): 20150072. doi:10.1098/rsbl.2015.0072. ISSN   1744-9561. PMC   4424620 . PMID   25878047.
  22. ↑ Kiel, Steffen; Kahl, Wolf-Achim; Goedert, James L. (March 2013). "Traces of the bone-eating annelid Osedax in Oligocene whale teeth and fish bones". Paläontologische Zeitschrift. 87 (1): 161–167. Bibcode:2013PalZ...87..161K. doi: 10.1007/s12542-012-0158-9 . ISSN   0031-0220.
  23. ↑ WoRMS, Genus Osedax
  24. ↑ Rouse, Greg W.; Goffredi, Shana K.; Johnson, Shannon B.; Vrijenhoek, Robert C. (February 5, 2018). "An inordinate fondness for Osedax (Siboglinidae: Annelida): Fourteen new species of bone worms from California". Zootaxa. 4377 (4): 451–489. doi: 10.11646/zootaxa.4377.4.1 . PMID   29690036. S2CID   13854107.
  25. ↑ Fujiwara, Yoshihiro; Jimi, Naoto; Sumida, Paulo Y. G.; Kawato, Masaru; Kitazato, Hiroshi (August 1, 2019). "New species of bone-eating worm Osedax from the abyssal South Atlantic Ocean (Annelida, Siboglinidae)". ZooKeys (814): 53–69. Bibcode:2019ZooK..814...53F. doi: 10.3897/zookeys.814.28869 . PMC   6333729 . PMID   30651712.
  26. ↑ Fujikura, Fujiwara & Kawato. ZOOLOGICAL SCIENCE 23: 733–740 (2006)

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