Associations between the White Sea colonial hydroidDynamena pumilaand microorganisms

Abstract

Marine sessile invertebrates with outer skeleton constitute additional substrate for a diverse group of epibiotic organisms. Colonial hydroids are no exception. Large numbers of motile and sessile organisms use hydroid colonies covered with chitinous perisarc for permanent or temporal attachment. Such epibiotic associations between colonial hydroids and microorganisms are poorly studied and mostly known for subtropical regions. There are no data about the development of such epibiotic association and type of its specificity yet. The present paper for the first time describes the epibiotic association of the colonial thecate hydroidDynamena pumilafrom the high latitude sea. We reconstruct the spatial and temporal development of such epibiotic community and analyse the organization of the multicomponent biofilm covering the hydroid colony. Comparison of the epibiotic community in different seasons indicates for holding out of the basal features and components of the community during the whole year. Ultrastructural investigations revealed that components of the biofilm affect the outer skeleton of the hydroid colony that results in penetration of the microorganisms into the skeleton and even soft tissues. Our data allow supposing that association of hydroidD. pumilawith a microorganism community has features of a symbiotic system.

Association between luminous bacteria and Hydrozoa in the northern Ionian Sea

“…A previous research reported that surface chitin-containing structures of the hydroid Aglaophenia octodonta (Stabili et al , 2006) are heavily colonized by luminous bacteria belonging to the genus Vibrio. Moreover, a recent study by Gorelova et al (2010) demonstrated a feeding activity of bacteria on the surface of the hydrozoans Dynamena pumila and Gonothyrea loveni , showing micro-perforations within the perisarc containing the microrganisms, presumably due to chitin lysis. In the present study, the occurrence of luminous bacteria in the investigated hydrozoan species could be related to differences in the chitin localization as well as presence or absence of the perisarc.…”

“…In particular, Bavestrello et al (1996, 2008), Siqueiros-Beltrones et al (2001), Di Camillo et al (2005, 2008) and Romagnoli et al (2007) described epibiotic bacteria, diatoms, and foraminiferans from both Mediterranean and tropical hydroids. Moreover, Gorelova et al (2010) observed by electron microscopy that the epibiotic community of the hydroid perisarc of Dynamena pumila and Gonothyraea loveni consisted of different microalgae and bacteria. These findings suggest many interactions between the hydroids and epibiotic microorganisms.…”

Molecular Identification and Ultrastructural and Phylogenetic Studies of Cyanobacteria from Association with the White Sea HydroidDynamena pumila(L., 1758)

“…Various cyanobacterial strains form associations with sponges, hydroids, corals, dinoflagellates, radiolarians, and tintinnids [1–8]. Mostly, the studies of cyanobacterial associations are limited to subtropical and tropical marine water systems.…”