Sabellaria alveolata versus Sabellaria spinulosa Reefs along the Italian Coasts: A New Methodological Proposal to Compare Different Growth Models

Abstract

Sabellaria species are among the most important frame-builders in temperate, shallow marine areas. These polychaetes are suspension feeders able to build bioconstructions using sand and shell fragments cemented with a sticky mucous. Such feature makes these invertebrates “unusual bioconstructors”, as they do not produce calcium carbonate. Sabellaridae reefs are widespread in the Mediterranean and along the Atlantic coast of Europe, but their sedimentological aspects are still poorly known. Over short time intervals, these bioconstructions can rapidly alternate between phases of growth, stasis and destruction during different seasons. In this paper, we compare reefs of two Sabellaria species (S. alveolata—Ostia, Roma and Tyrrhenian Sea; S. spinulosa—Torre Mileto, Foggia and Adriatic Sea) found at two different sites along the Italian coast. We describe the morphology of worm tubes at the macro- and microscale. Similarities and differences are discussed based on eco-biological features and physical environmental conditions. This work shows a measurement and observation scheme for this type of bioconstructions that has been verified at both the macro- and microscale and which was shown to be useful for defining evolutionary trends of sabellarian bioconstructions. The monitoring parameters were identified and verified over a long period.

Feasibility of the Sabellarid Reef Habitat Restoration

“…The subsequent loss of other fragments was probably due to erosion rather than to the effectiveness of the fixing method, since the total surface area of the remnant reef fragments showed a gradual reduction, especially from T0 to T2. In fact, during the period between T1 and T2 (from February to July 2020) the reduction of the surface area was higher possibly due to seasonal dynamics of the sabellarid reef that usually undergoes erosion during winter also because of adverse climatic conditions (Lisco et al, 2021). The fact that the transplant units persisted after winter suggests that the translocation method herein used may be effective for restoration purposes.…”

“…No significant increase nor reduction of the reef surface area was observed throughout the rest of the experiment, although the growth phase of Sabellaria reef in the Mediterranean Sea is reported to occur during spring-summer both due to somatic growth and recruitment (Lisco et al, 2017(Lisco et al, , 2021Gravina et al, 2018). This may suggest that the erosion process, initially attributable to the effect of winter climatic conditions stopped after winter but it was not counteracted by spring growth possibly due to the natural rearrangement of the biogenic structures adapting to the local environmental conditions at the transplant sites.…”

Architecture and tube structure of Sabellaria spinulosa (Leuckart, 1849): Comparison with the Mediterranean S. alveolata congener

“…The bioconstruction described from the Casarza beach represents a new record for the Adriatic Sea (Gadaleta et al, 2015;Gravina et al, 2018;Lezzi et al, 2015;Lisco et al, 2017Lisco et al, , 2021. Particularly, the investigated aggregations of S. spinulosa are the closest to the site of the Abruzzo coast Torre del Cerrano, where the species shows its maximum abundance and development (Gadaleta et al, 2015).…”

“…The sabellariid polychaete Sabellaria spinulosa (Leuckart, 1849) is a tube‐dwelling species that may form fragile bioconstructions consisting of densely packed individuals living inside tubes of agglutinated sandy particles. Tubes grow adhering sub‐parallel to each other and are separated by inter‐tube areas of loose sand (Gravina et al, 2018; Lisco et al, 2017, 2021). The detailed architecture of bioconstructions and the tube structure of S. spinulosa are still unknown, mostly in comparison to other Sabellariids such as the Atlantic‐Mediterranean Sabellaria alveolata (Bodeur et al, 1987; Gruet, 1984; Sanfilippo et al, 2019) and the Pacific Phragmatopoma californica (Scholl, 1958).…”

“…Sabellaria spinulosa , described from the North Sea (Leuckart, 1849), is distributed in the Northeastern Atlantic: English coasts of the North Sea, east English Channel, north and west Wales and eastern Ireland coasts (Attrill et al, 1996; Braithwaite et al, 2006; George & Warwick, 1985; Hendrick et al, 2011; Hendrick, 2007; Jones, 1972). The species also occurs in the western and central Mediterranean: Tunisian and Algerian coasts (Ayari et al, 2009; Cantone et al, 1978; Molinier & Picard, 1953; Seurat, 1929, 1934; Zghal & Bouaziz‐Azzouna, 1982), southeastern Sicily coast (Schimmenti et al, 2015), Tyrrhenian Sea (La Porta & Nicoletti, 2009), Ionian Sea (Cantone et al, 1980) and Adriatic Sea (Gadaleta et al, 2015; Gravina et al, 2018; Lezzi et al, 2015; Lisco et al, 2017, 2021). A record that requires confirmation is that of the subspecies S. spinulosa alcocki from the Aegean Sea (Simboura & Zenetos, 2002) as well as the attribution of some Adriatic and Tyrrhenian occurences to a distinct species S. alcocki (Castelli et al, 2008; Gadaleta et al, 2015; Nicoletti et al, 2001), originally from the Indian Ocean (Day, 1967; Gravier, 1906).…”