Pyrosoma atlanticum
Encyclopedia
Pyrosoma atlanticum is a pelagic species
of marine colonial
tunicate
in the class Thaliacea
. It is found in temperate waters worldwide. The name of the genus comes from the Greek
words "pyros" meaning "fire" and "soma" meaning "body", referring to the bright bioluminescent light sometimes emitted. The specific name
"atlanticum" refers to the Atlantic Ocean
from where the species was first described in 1804 by the French naturalist, François Péron
.
s form a rigid tube which may be pale pink, yellowish or bluish. One end of the tube is narrower and is closed while the other is open and has a strong diaphragm. The outer surface or test is gelatinised and dimpled with backward pointing, blunt processes. The individual zooid
s are up to 8.5 mm (0.3 in) long and have a broad, rounded branchial sac with gill
slits. Along the side of the branchial sac runs the endostyle
which produces mucus
filters. Water is moved through the gill slits into the centre of the cylinder by cilia
pulsating rhythmically. Plankton
and other food particles are caught in mucus filters in the process and the colony is propelled through the water at the same time. Pyrosoma atlanticum is bioluminescent and can generate a brilliant blue-green light when stimulated.
comparing different zooplankton
organisms, it was found that colonies of Pyrosoma atlanticum were the most efficient grazers of particles above 10 µm in diameter, catching a higher proportion of the particles than other grazers. This implies that Pyrosoma atlanticum uses high biomass intake as a strategy rather than investing in energy conservation mechanisms.
Growth occurs by new rings of zooids being budded off around the edge of the elongating colony. There are a pair of luminescent organs on either side of the inlet siphon of each zooid. When stimulated, these turn on and off, causing rhythmic flashing. There is no neural pathway between the zooids but each responds to the light produced by other individuals and even by light from other nearby colonies.
shrimp Funchalia were found living inside colonies of Pyrosoma atlanticum. Other amphipods
also lived there including the hyperiids
Phronima
and Phronimella spp.
Predators
of Pyrosoma atlanticum include various bony fish such as the spiky oreo
, the big-eyed cardinalfish
and the pelagic butterfish
, dolphin
s and whale
s.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of marine colonial
Colony (biology)
In biology, a colony reference to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defense or the ability to attack bigger prey. Some insects live only in colonies...
tunicate
Tunicate
Tunicates, also known as urochordates, are members of the subphylum Tunicata, previously known as Urochordata, a group of underwater saclike filter feeders with incurrent and excurrent siphons that is classified within the phylum Chordata. While most tunicates live on the ocean floor, others such...
in the class Thaliacea
Thaliacea
The Thaliacea comprise a class of marine animals within the subphylum Tunicata. Unlike their bottom-dwelling relatives the ascidians, thaliaceans are free-floating for their entire lifespan. The group includes both solitary and colonial species.-Anatomy:...
. It is found in temperate waters worldwide. The name of the genus comes from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
words "pyros" meaning "fire" and "soma" meaning "body", referring to the bright bioluminescent light sometimes emitted. The specific name
Specific name
Specific name in zoological nomenclature refers to the second part within the name of a species...
"atlanticum" refers to the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
from where the species was first described in 1804 by the French naturalist, François Péron
François Péron
François Auguste Péron was a French naturalist and explorer. He is credited with the first use of the term anthropology.-Explorations:...
.
Description
A colony of Pyrosoma atlanticum is cylindrical and can grow up to 60 cm (2 ft) long and 4-6 cm wide. The constituent zooidZooid
A zooid or zoöid is a single animal that is part of a colonial animal. The zooids can either be directly connected by tissue or share a common exoskeleton...
s form a rigid tube which may be pale pink, yellowish or bluish. One end of the tube is narrower and is closed while the other is open and has a strong diaphragm. The outer surface or test is gelatinised and dimpled with backward pointing, blunt processes. The individual zooid
Zooid
A zooid or zoöid is a single animal that is part of a colonial animal. The zooids can either be directly connected by tissue or share a common exoskeleton...
s are up to 8.5 mm (0.3 in) long and have a broad, rounded branchial sac with gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
slits. Along the side of the branchial sac runs the endostyle
Endostyle
An endostyle is a longitudinal ciliated groove on the ventral wall of the pharynx which produces mucus to gather food particles. It is found in urochordates and cephalochordates, and in the larvae of lampreys. It aids in transporting food to the esophagus. It is also called the hypopharyngeal groove...
which produces mucus
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
filters. Water is moved through the gill slits into the centre of the cylinder by cilia
Cilium
A cilium is an organelle found in eukaryotic cells. Cilia are slender protuberances that project from the much larger cell body....
pulsating rhythmically. Plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
and other food particles are caught in mucus filters in the process and the colony is propelled through the water at the same time. Pyrosoma atlanticum is bioluminescent and can generate a brilliant blue-green light when stimulated.
Distribution and habitat
Pyrosoma atlanticum is found in temperate waters in all the world's oceans, usually between 50°N and 50°S. It is most plentiful at depths below 250 m (800 ft). Colonies are pelagic and move through the water column. They undergo a large diurnal migration, rising towards the surface in the evening and descending around dawn. Large colonies may rise through a vertical distance of 760 metres (2,500 ft) daily and even small colonies a few millimetres long can cover vertical distances of 90 metres (300 ft).Biology
In a study in the Indian OceanIndian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
comparing different zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
organisms, it was found that colonies of Pyrosoma atlanticum were the most efficient grazers of particles above 10 µm in diameter, catching a higher proportion of the particles than other grazers. This implies that Pyrosoma atlanticum uses high biomass intake as a strategy rather than investing in energy conservation mechanisms.
Growth occurs by new rings of zooids being budded off around the edge of the elongating colony. There are a pair of luminescent organs on either side of the inlet siphon of each zooid. When stimulated, these turn on and off, causing rhythmic flashing. There is no neural pathway between the zooids but each responds to the light produced by other individuals and even by light from other nearby colonies.
Ecology
Five specimens of the penaeidPenaeidae
Penaeidae is a family of prawns, although they are often referred to as penaeid shrimp. It contains many species of economic importance, such as the tiger prawn , whiteleg shrimp, Atlantic white shrimp and Indian prawn. Many prawns are the subject of commercial fishery, and farming, both in marine...
shrimp Funchalia were found living inside colonies of Pyrosoma atlanticum. Other 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...
also lived there including the hyperiids
Hyperiidae
Hyperiidae is a family of amphipods, containing the following genera:*Euthemisto Bovallius, 1887*Hyperia Latreille in Desmarest, 1823*Hyperiella Bovallius, 1887*Hyperoche Bovallius, 1887*Laxohyperia M. Vinogradov & Volkov, 1982...
Phronima
Phronima
Phronima is a small, deep sea hyperiid amphipod of the family Phronimidae. It is found throughout the world's oceans, except in polar regions. The body of Phronima is transparent. Females attack salps, using their mouth and claws to eat the animal and hollow out its gelatinous shell. She then...
and Phronimella spp.
Predators
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
of Pyrosoma atlanticum include various bony fish such as the spiky oreo
Spiky oreo
The spiky oreo, Neocyttus rhomboidalis, is an oreo of the genus Neocyttus, found in all southern oceans at depths of between 200 and 1,300 m. Its length is up to 40 cm.-References:...
, the big-eyed cardinalfish
Big-eyed cardinalfish
The big-eyed cardinalfish, bigeye cardinalfish, or bigeye, Epigonus lenimen, is a deepwater cardinalfish of the genus Epigonus, found in southern temperate waters at depths of between 500 and 800 m...
and the pelagic butterfish
Pelagic butterfish
The pelagic butterfish, Schedophilus maculatus, is a medusafish of the genus Schedophilus found in all warm oceans. Its length is up to about 30 cm.-References:...
, dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...
s and whale
Whale
Whale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...
s.