Bioerosion features of boring polydorid polychaetes in the North Adriatic Sea

Abstract

Considering the pivotal role played by erosive organisms in the marine habitat and the scanty knowledge of this phenomenon in the Mediterranean Sea, the present study aimed to identify the pioneer excavating organisms occurring in the first stages of bioerosion, providing the first estimation of their rate of erosion along the North Adriatic Sea. Bioerosion activity was investigated by deploying sets of limestone panels for a period of 2 years. Moreover, micro-computed tomography was used for the first time to study polychaete erosion, confirming it is a very useful tool for the description of erosion processes. Blocks were placed in the touristic harbor Marina Dorica (Ancona) in July 2017 and periodically collected, the first time after a 6-month period, then bimonthly. Two species of the polychaete genus Polydora were the only boring organisms that settled on the experimental substrates. Erosion rate was estimated by measuring the holes produced by both worm species, and the eroded volumes obtained by resin casts of the holes. Polydora appeared after 6 months of exposure significantly changing its density rates (holes·100 cm−2·month−1) during the exposure, being comparable with densities reported from tropical areas. The erosion rate on the contrary is lower, reaching values of 0.053 g·cm−2·year−1.

Leptogorgia sarmentosa (Anthozoa: Octocorallia) in NE Sardinia (Mediterranean Sea): distribution and growth patterns

“…In particular, Leptogorgia sarmentosa appears to be completely absent along the Sardinian coast with the only exception of rare records along the NE side. This area is hosting also unique Sardinian populations of the gorgonian Eunicella verrucosa (Canessa et al 2022) and almost all known colonies of the zoantharian Savalia savaglia (Bertoloni, 1819) (Pulido Mantas et al 2022). This unusual distribution pattern is validated by the fact that these species are generally well recognized by SCUBA divers and that they were never observed during the numerous ROV surveys off Sardinia (Bo et al 2015;Cau et al 2015;Gori et al 2019;Moccia et al 2014Moccia et al , 2021.…”

Black Mantle Tissue of Endolithic Mussels (Leiosolenus spp.) Is Cloaking Borehole Orifices in Caribbean Reef Corals

“…The siphons use openings in the substrate surface for contact with the surrounding seawater [20]. The outline of such openings is described as "figure-of-eight" or "dumbbell" [3][4][5]8,[20][21][22][23] shape, not to be confused with the twin openings of U-shaped excavations of Polydora worms (Polychaeta) [24][25][26][27][28] and the perforations made by boring clionaid sponges (Porifera) [25,29].…”