A guide to the deep-water sponges of - NMFS Scientific Publications ...

77. Asbestopluma ramosa Koltun, 1958
Description. This sponge is flagelliform. This species
appears as described by Koltun (1959) and often
consists of numerous more or less cylindrical branches
diverging from one point and arranged in one plane.
We have observed up to five branches that diverge at
multiple points, however. Branches may be bent or
slightly curved. Occasionally the sponge is markedly
elongated and has a ramified, stalk-like appearance
with many closely spaced fine projections (according to
Koltun). Height is to at least 72 cm with branches up to
1.5 cm thick. Color in life is light yellow, light orange,
or creamy white; the lower portion is often devoid of
the fine lateral projections and consequently a darker
color, often brown.
Skeletal structure. Styles are arranged in a central
axis with side-tracts running into the lateral projections;
styles are 238–1500 × 7–18 µm and anisochelae
are 10–17 µm.
Zoogeographic distribution. Widespread and locally
abundant. In Alaska – central Aleutian Islands, eastern
Gulf of Alaska (near the Fairweather Ground). Elsewhere
– North Pacific Ocean (Kuril Islands, Vancouver
Island), Arctic Ocean (Southwest Barents Sea, Kara
Sea – Vilkitsky Strait, Laptev Sea – Shokalsky Strait, East
Siberian Sea, Greenland Sea, and Baffin Bay), and
North Atlantic Ocean (Faroe Islands).
Habitat. In Alaska – attached with a holdfast to bedrock,
mudstone, boulders, cobbles, and occasionally
hexactinellid sponge skeletons at depths between 395
and 1812 m; more abundant at depths shallower than
1200 m. Elsewhere – reported on ooze and sandy-ooze
bottoms at depths between 41 and 1134 m and temperatures
of 1.64 to 4.8°C.
Remarks. This species occasionally has ophiuroid associates
particularly at depths shallower than 500 m. It
occurs within the same depth range as Esperiopsis flagrum
but attaches to hard substrate rather than anchoring in
soft sediment. A. ramosa may have a carnivorous feeding
habit like other Cladorhizidae so collected specimens
may have small crustaceans trapped in their outer tissues.
Photos. 1) Specimen collected at a depth of 1715 m
in the central Aleutian Islands. Grid marks are 1 cm 2 .
2) Specimen collected at a depth of 1501 m in the
eastern Gulf of Alaska. 3) Specimen observed in situ
at a depth of 843 m in the central Aleutian Islands. 4)
Close-up view of same specimen as in photo 3 showing
detail of the closely spaced fine projections.
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