''Agelas schmidti'', commonly known as the brown tubular sponge, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

demosponge Demosponges (Demospongiae) are the most diverse class in the phylum Porifera. They include 76.2% of all species of sponges with nearly 8,800 species worldwide (World Porifera Database). They are sponges with a soft body that covers a har ...

. It occurs at moderate depths in the Gulf of Mexico and the Caribbean Sea and often has a

colonial Colonial or The Colonial may refer to: * Colonial, of, relating to, or characteristic of a colony or colony (biology) Architecture * American colonial architecture * French Colonial * Spanish Colonial architecture Automobiles * Colonial (1920 au ...

coral growing over the surface. The type locality is Puerto Rico.

Description

The brown tubular sponge is a large sponge forming mounds that may be a metre (yard) across. The base is encrusted on the substrate or may develop lobes but above this there are several dozen large vertical tubes, narrowing at the top, each with a hollow centre or atrium and a large hole or

osculum The osculum (plural "oscula") is an excretory structure in the living sponge, a large opening to the outside through which the current of water exits after passing through the spongocoel. Wastes diffuse into the water and the water is pumped thr ...

at the apex. They are up to long and wide and are soft, elastic and resilient. The walls are strengthened by a skeleton of

spongin Spongin, a modified type of collagen protein, forms the fibrous skeleton of most organisms among the phylum Porifera, the sponges. It is secreted by sponge cells known as spongocytes. Spongin gives a sponge its flexibility. True spongin is found ...

fibres and tiny calcareous

spicule Spicules are any of various small needle-like anatomical structures occurring in organisms Spicule may also refer to: *Spicule (sponge), small skeletal elements of sea sponges *Spicule (nematode), reproductive structures found in male nematodes ( ...

s. On the side of these tubes there are deep grooves and shallow cup shaped depressions up to across each occupied by a dark reddish brown

zoanthid Zoanthids ( order Zoantharia also called Zoanthidea or Zoanthiniaria) are an order of cnidarians commonly found in coral reefs, the deep sea and many other marine environments around the world. These animals come in a variety of different coloniz ...

(''

Parazoanthus ''Parazoanthus'' is a genus of anemone-like anthozoans in the order Zoantharia. Species The following species are recognized in the genus ''Parazoanthus'': * '' Parazoanthus aliceae'' Carreiro-Silva, Ocaña, Stanković, Sampaio, Porteiro, Fabri ...

sp.''). This is a

coral living

symbiotically Symbiosis (from Ancient Greek, Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different Organism, biological organisms, be it Mutualism (biolog ...

with the sponge and the polyps are connected together by tissue called coenenchyme inside the atrium of the sponge. The general colour of the sponge is brownish orange or brick red.

Distribution and habitat

The brown tubular sponge is found in the

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

, the

Greater Antilles The Greater Antilles ( es, Grandes Antillas or Antillas Mayores; french: Grandes Antilles; ht, Gwo Zantiy; jam, Grieta hAntiliiz) is a grouping of the larger islands in the Caribbean Sea, including Cuba, Hispaniola, Puerto Rico, Jamaica, and ...

Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and Unincorporated ...

, the northern coast of

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

and the northern part of the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

. It typically occurs on reefs at depths between in positions where there is a strong current and the water is clear.

Biology

The brown tubular sponge is a

filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

. The current flowing over the top of the sponge draws in water through small pores near the base called ostia. These are lined by

flagellated A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have fro ...

cells called

choanocyte Choanocytes (also known as "collar cells") are cells that line the interior of asconoid, syconoid and leuconoid body types of sponges that contain a central flagellum, or ''cilium,'' surrounded by a collar of microvilli which are connected by a th ...

s. The food particles are engulfed by these and the water exits through the osculi. Only very small particles can enter the sponge and 80% of its nourishment comes from bacteria sized particles. The brown tubular sponge produces a

secondary metabolite Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the norm ...

, sceptrina, an

alkaloid Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...

with

antimicrobial An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals ar ...

properties.

References

{{Taxonbar, from=Q3519705 Agelasida Sponges described in 1902