Life history of Cornularia cornucopiae (Anthozoa: Octocorallia) on the Conero Promontory (North Adriatic Sea)

The life cycle of the stoloniferan Cornularia cornucopiae (Pallas, 1766) (Anthozoa: Octocorallia) was studied from March 2009 to October 2010 on the rocky cliff of the Conero Promontory (North Adriatic Sea, 43°34.865′ N, 13°34.320′ E). In this area the species showed unusual high densities never recorded in other sites of the Mediterranean Sea. The density trend of the species showed a marked seasonal cycle, with a winter minimum of about 1000 polyps m^?2 and a summer maximum of about 30,000 polyps m^?2. In accordance with other Mediterranean literature data, polyps were fertile during spring–summer, from March to August, but the number of eggs per polyp continuously decreased during this span of time. Variations of polyp density were strongly correlated to water temperature, which can be considered the main environmental factor triggering this seasonal behaviour. The possibility, for C. cornucopiae, to face adverse winter conditions is probably related to the presence of a characteristic perisarcal envelope covering the stolon and the calyx of each polyp, which isolates the living tissues from the exterior. During winter, polyps degenerate but the stolons remain dormant inside their envelopes. The perisarc covering represents a morphological convergence of C. cornucopiae with benthic hydrozoans. As the latter, the studied stoloniferans are able to live in habitats characterized by periodic favourable conditions thanks to a seasonal life strategy. A similar trend is shared also by other important components (cnidarians and some sponges) of the filter‐feeding community of the North Adriatic Sea. Differently to the Western Mediterranean basin, this area is characterized by high food availability all year around, so benthic organisms are strongly constrained by the very low winter temperatures.     

Ricerche eseguite nelle cave di calcare di Monte Rombolo per rintracciare fori di sonda

Riassunto Vengono esposti i criteri seguiti per determinare con metodi acustici e magnetometrici la direzione dei fori di sonda quando si presenta la necessità di ricercarli ad un determinato livello e quando si teme che le indicazioni topografiche non siano sufficienti alla loro determinazione causa la deviazione frequente che questi fori hanno dalla verticale.

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Zusammenfassung Man erörtet die Verfahren die verfolgt würden um mit akustischen und magnetometrischen Messungen die Richtung der Rohrlöcher zu bestimmen, wenn die Notwendigkeit besteht ein Bohrloch in einer bestimmten Sole zu erforschern und wenn die topographischen Hinweise nicht genügend zu ihrer Bestimmung sind, infolge der häufigen eintretenden Abweichungen dieser Bohrlöcher von der Vertikale.