Pumpworm

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Pumpworm
Sabellaria spinulosa (Fig. 1, top left). A monograph of the British marine annelids 1922 Plate CXII.

Sabellaria spinulosa  (Fig. 1, top left). A monograph of the British marine annelids 1922 Plate CXII.

Systematics
Subclass : Palpata
Order : Canalipalpata
Subordination : Sabellida
Family : Sand corals (Sabellariidae)
Genre : Sabellaria
Type : Pumpworm
Scientific name
Sabellaria spinulosa
( Leuckart , 1849)

The Pümpwurm or tube sand coral ( Sabellaria spinulosa ) is a sessile, röhrenbauender , reef-building, as filter feeders living polychaete (Polychaeta) from the family of sandy coral (Sabellariidae), which in the eastern Atlantic Ocean can be found.

features

Sabellaria spinulosa has a thin, cylindrical and smooth, wine-red body with 40 segments spotted brown on the thorax and a light brown colored tail section that tapers gradually towards the rear end, up to about 3 cm long . The rearmost section, referred to as the post-abdomen, lies folded forward in an abdominal groove of the abdomen, with the anus pointing forward. At sexual maturity, the females turn purple and the males whitish.

The outer bristles of the operculum taper distally and are covered with 4 to 5 teeth, of which the middle one is longest and sawn on both sides. The middle bristles of the operculum are kneeled, hollowed out subdistally and tapering distally. The inner bristles of the operculums are similar to the central ones, but longer. Ventrally on the mouth there are numerous thread-like tentacle filaments, and between the tentacle tips there are two short, conical palps ventrally .

The first bristle-bearing segment has oval neuropodia on which there are toothed capillary-like bristles. On the second bristle-bearing segment there are toothed capillary-like bristles and a small triangular cirrus on the neuropodia . From the second bost-bearing segment on, each segment has gills , the length of which decreases towards the rear.

The last 3 segments of the thorax have rectangular notopodia , each with 8 to 10 large paddle-shaped bristles. The neuropodia do not carry cirrus, and their bristles are similar to those on the notopodia, but smaller. The abdomen is characterized by notopodia with lateral, fleshy flaps on which short hooks with about 5 to 6 teeth each sit, while the papilla-like neuropodia there are covered with long, feather-like capillary-like bristles.

Sabellaria spinulosa is very similar to the closely related Sabellaria alveolata and is therefore difficult to tell apart. It differs from this mainly in the shape of the bristles in the outer and middle rows on the operculum. In addition, the reefs formed by their living tubes are less powerful.

Residential tube

The living tubes of Sabellaria spinulosa consist of grains of sand, which are sifted out of the flowing water with the paleae at the mouth, brought to the upper edge of the tube with the tentacles and cemented with the solidified mucus (cement substance) separated by the cement glands on the 2nd segment . Often the animals appear in large numbers next to each other with their living tubes, so that the openings of the tubes result in a honeycomb-like pattern.

Development cycle

Sabellaria spinulosa is single sex and is around 2 to 5 years old. In July, the females turn purple and the males whitish and release their gametes so that fertilization takes place in open sea water. The zygotes develop into free-swimming trochophora larvae in around 12 hours , which, depending on the environmental conditions, live as zooplankton for 6 weeks to 2 months , which feed on phytoplankton . The mature larva is finally recognizable as a sabellariid by its bristles (paleae) on the mouth and sinks to the ground in order to metamorphose into a creeping worm and to build a living tube. The larvae prefer to settle on existing reefs of their fellow species. However, the reefs of Sabellaria spinulosa do not reach the size of those of Sabellaria alveolata , but rather form thinner crusts, and the annelids often also form individual living tubes on solid substrate such as stones or mollusc shells.

nutrition

Sabellaria spinulosa feeds as filter feeders of detritus .

Distribution, habitat and endangerment

Sabellaria spinulosa is widespread in the eastern Atlantic Ocean to the Gulf of Guinea , in the North Sea to the Kattegat , in the Mediterranean and in the Black Sea . The polychaet lives in the intertidal zone on rock or sand, where it builds cylindrical living tubes from slime and grains of sand, which can form reefs up to several hundred meters in size. In the 19th century there were more than 20 large sand coral reefs of Sabellaria spinulosa and Sabellaria alveolata in the Wadden Sea of the German Empire , and until the 1930s the sand corals were considered the dominant form below the tidal zone of the North Sea. In the meantime, there are no longer any sand coral reefs in German waters, which is why the species is classified as endangered by the Federal Agency for Nature Conservation. In 2014, the reasons for the decline were the expansion of ports, dredging work and, in particular, trawling . The UK Biodiversity Group and the Naturschutzbund Deutschland also cite trawling as the main reason for the death of sand corals. However, a study by Ralf Vorberg in 2000 did not succeed in demonstrating a direct connection between the use of bottom trawls and the disappearance of the bristle worms.

literature

Web links

Commons : Pumpworm ( Sabellaria spinulosa )  - Collection of images, videos and audio files