Size

patches from a few cm to a few m in area

Description

Mats of Dendrilla antarctica a few cm thick often carpet shallow rocky surfaces, sometimes extending over 3 or 4 square meters. Although the species is typically almost luminescent yellow it can have a variety of colour. Its prickly appearance makes it quite distinctive but it is does not feel spiky to touch, its tissue is soft and squashy. Other than the spiky texture it takes the form of whatever it is growing over, so when it encrusts macroalgae it often extends in lobes into the water column – slicing through a lobe reveals the alga inside entirely surrounded by the sponge. D. antarctica is a good competitor for space, so underneath encrusting sheets can often be found a wide variety of animals that it has suffocated. The tissues of this species have antibiotic properties and contain endosymbiotic diatoms. Frequently one or more individuals of the large sea slug A. kerguelenensis are seen on any large patches of the sponge. Occasionally found on the under-surfaces of boulders but if lifted out of the water it dries out to a thin yellow slime.

Source Name

British Antarctic Survey

Description

Grows as distinctive yellow or brown spheres with large trumpet-shaped papillae. The sponge reaches up to 50cm diameter.

Ecology

Inflatella belli is a suspension feeder and contains diatoms living within its cells, but their role is unclear.

Description

Original description by Kirkpatrick (1907):
Sponge dome-shaped or spheroidal, attached or free. Surface beset with a dense short pile of cortical microtyles; with several usually elongated papillae with or without a large terminal orifice. Dermal pores distributed over the cortex, each pore opening into a single tubular canal in the cortex; the mouth or pore of the pore-canal is guarded with a ring of radiating cortical tyles. Flagellated chambers diplodal.
Skeleton formed mainly of radiating fibres composed of styles, with diverging brushes of spherostyles near the surface. Cortex with a surface-layer of densely packed tufts of small vertical tyles, and a subcortical layer of tangential styles and tyles.
Spicules.- Spherostyles 8 mm in length by 30 μm in diameter in the middle, and 14 μm in the region below the distal knob; distal knob 28 μm in diameter, hemispherical, with granular surface and with a few square teeth or serrations on the edge.
Styles straight, fusiform, blunt-pointed, 2.8 mm in length, 41 μm in diameter in the middle, 23 μm in diameter at the rounded end.
Cortical tyles curved, 146 μm long, head 3.25 μm in diameter; neck slender, 2.75 μm thick, with broad oar-blade-like shaft, but circular in section, 7 μm thick.
Styles of lower cortical tangential layer, also in choanosome, 900x20 μm. Tyles of the same layer nearly straight, 270 μm long, with head 7 μm in diameter and relatively thick neck 6.8 μm in diameter.
Slender, curved tyles, 460x10 μm scattered in choanosome.
Young specimens are oval, with one long closed papilla; the bundles of divergent exotyles are more or less separate and distinct, and the distal knobs retained and not broken off.

Source Name

British Antarctic Survey

Description

White or orange head, either spherical or oblong, on a smooth, long, slender stalk. The head is up to 2.5 cm diameter and the entire sponge grows up to 20cm high.

Ecology

Stylocordyla borealis is a suspension feeder. It occurs in patches, probably due to its mode of reproduction, in which eggs are incubated inside the mother sponge and released as fully complete young sponges to settle nearby. Stylocordyla borealis has a system of rooting spicules which enables it to attach and grow in soft bottomed areas.

Source Name

British Antarctic Survey

Description

Greenish grey to yellow. Hemispherical and bristly with one or two large conical papillae which contract when disturbed. The sponge reaches a diameter of up to 11cm.

Ecology

Suspension feeder, preyed upon by seastars such as Perknaster fuscus (when juvenile) and Odontaster meridionalis, and by the dorid nudibranch Austrodoris kerguelenensis. Its larvae have been observed in aquaria to disperse by crawling

Source Name

British Antarctic Survey

Size

mounds typically between 20cm to exceptionally >1m in height

Description

Mounds of Mycale acerata and the starfish that eat them are a common feature of hard bottom communities. Although it has no programmed shape (like many sponges) it tends to form mounds like those made by termites with many smooth rounded lobes protruding. Sometimes M acerata is the most common sponge and one of the most important contributors of biomass. This sponge is particularly notable for being one of the few sponges, or even any Antarctic invertebrates, that grows quickly. Despite this it still grows somewhat slower than the fastest growing temperate or tropical sponges. In periods of food shortage this species and some others may actually shrink over considerable periods of time. It is not known how long this sponge lives but it could probably be many decades.

Source Name

British Antarctic Survey

Description

White, yellow or orange in colour. There are several morphs, many of which were once considered separate species. The commonly seen types are large (up to around 50cm high) and barrel or vase shaped, while the budding type is smaller (up to 15cm high) and vase or egg shaped.

Ecology

Observations suggest that glass sponges such as Rossella racovitzae are important in the colonisation of soft substrates. They deposit spicules which eventually form hard mats that other sponges, unable to colonise soft surfaces, can settle on. Rossella racovitzae reproduces by asexual budding as well as sexually. Asexual reproduction is unusual in Antarctic sponges. This sponge is a suspension feeder and contains diatoms living within its cells, but their role is unclear. The diatoms are photosynthetic and can use light which is transferred into the sponge body by the sponge spicules, which act as natural optical fibres.
The main predators of Rossella racovitzae are seastars, and the dorid nudibranch Austrodoris kerguelenensis.

Source Name

British Antarctic Survey

Description

Pale with distinctive flattened fronds and a hard stalk. Slow-growing, reaching a height of up to 50cm

Ecology

Calyx arcuarius is a suspension feeder. Its predators include the seastars Odontaster meridionalis and Acodontaster hodgsoni, and the dorid nudibranch Austrodoris kerguelenensis, although extracts from it have been shown to have antipredator and antibacterial effects.

Source Name

British Antarctic Survey

Description

Vivid red and thickly branching, reaching a size of up to 30cm high

Ecology

Kirkpatrickia variolosa is a suspension feeder and preyed on by seastars, particularly Perknaster fuscus when juvenile, and Acodontaster conspicuus. Derivatives from Kirkpatrickia variolosa have been found to have antitumour and antiviral properties, and are being trialled as potential anti-cancer drugs.

Source Name

British Antarctic Survey

Description

Round, white or pale yellow body, covered in distinctive sticking-out tufts of long spicules. Cinachyra antarctica is a slow-growing sponge and reaches up to 30cm high.

Ecology

Sponges are suspension feeders, and in Antarctica are commonly preyed on by starfish, however the spicules on Cinachyra antarctica probably act as a defence against predators, preventing them from reaching the sponge body.
Some estimates have calculated that Cinachyra antarctica may reach 1,550 years in age. However there is no way to directly determine the age of a sponge, so this estimate was derived using oxygen consumption and metabolic rate as an approximate measure.

Source Name

British Antarctic Survey

Size

up to nearly 2m in height and >1 m wide

Description

Anoxycalyx joubini, often referred to as a volcano sponge, is a large vase or pear shaped sponge occurring as singletons or small groups. Some are tall and wide enough for a person to fit inside. The pores in the walls are quite obvious, especially inside it. Such pores can harbour a wide range of other animals: looking inside can reveal many arthropods particularly amphipods but also sometimes pycnogonans and shrimps as well as many types of worm. This species grows very slowly and specimens may be very old. These sponges are a good location to see the yellow seastar Acodontaster conspicuous, which may even occur in clusters over it.

Source Name

British Antarctic Survey

Description

Identification is very difficult without expert knowledge. Microxina benedeni is usually white, orange or pink and irregularly shaped, growing up to 18cm high.

Ecology

Microxina benedeni is a suspension feeder and contains diatoms living within its cells, but their role is unclear. Its predators include the dorid nudibranch Austrodoris kerguelenensis.

Source Name

British Antarctic Survey

Description

White and club shaped or branching, with a smooth surface. Homaxinella balfourensis is attached to the substrate by stolons or a root system and grows up to 1m high, with 10cm long branches

Ecology

Homaxinella balfourensis grows relatively rapidly in comparison to other Antarctic sponges (although still very slowly by tropical sponge standards). It contains substances with antifreeze properties, and can defend itself to some extent against diatom fouling which might otherwise interfere with respiration and feeding. It is a suspension feeder and is preyed on by seastars.
Homaxinella balfourensis contains diatoms living within its cells, but their role is unclear.