| Title | Epidemic Mortality of the Sponge Ircinia variabilis (Schmidt, 1862) Associated to Proliferation of a Vibrio Bacterium |
| Abstract | In recent years, several episodes of mass mortality
of sessile epibenthic invertebrates, including sponges,
have been recorded worldwide. In the present study, we
report a disease event on Ircinia variabilis recorded in
September 2009 along the southern Adriatic and Ionian seas
(Apulian coast), with the aim to quantify the mortality
incidence on the sponge population, to investigate the effect
of the disease on the sponge tissues and to assess whether
the disease is associated with vibrios proliferation. The
injured sponges showed wide necrotic areas on the surface
or disruption of the body in several portions. Necrotic areas
were whitish and often were covered with a thin mucous
coat formed by bacteria. In the most affected specimens,
sponge organisation resulted partial or complete loss, with
the final exposure of the dense skeletal network of spongine
fibres to the environment. The results of microbiological
cultural analysis using in parallel Marine Agar 2216 and
thiosulphate/citrate/bile salts/sucrose agar demonstrated
that, in affected specimens, vibrios represented 15.8 % of
the total I. variabilis surface culturable bacteria. Moreover,
all the isolated vibrios, grown from the wide whitish areas
that characterize the surface of the diseased sponges, were
identified, and their assignment to the Vibrio rotiferianus
was consistent with phylogenetic analysis and data of morphological,
cultural and biochemical tests. Studies on V.
rotiferianus have shown that its pathogenicity, with respect
to various aquatic organisms, is higher than that of Vibrio
harveyi. The factors triggering the disease outbreak in Ircinia
variabilis populations remain unclear. At present, we can
hypothesize the involvement in the disease of a synergetic
mechanism that, under stressful physiological conditions
(high temperature, elevated nutrients and reduced water flow),
induces sponge pathogens, in our case V. rotiferanius, to
become virulent, making sponges unable to control their
proliferation. Additional studies are needed to understand
the etiological processes as well as the factors involved in
sponges recovering fromthis epidemic event allowing themto
face mass mortality. A drastic reduction of sponge-specific
representatives could have marked a negative impact on the
environmental health on account of their role in the sea
remediation processes as filter-feeding organisms. |
| Source | Microbial ecology 64 (3), pp. 802–813 |
| Keywords | BENTHIC SUSPENSION FEEDERSMASS-MORTALITYMARINE SPONGEEXTRACELLULAR PRODUCTS |
| Journal | Microbial ecology |
| Editor | Springer-Verlag,, New York,, Stati Uniti d'America |
| Year | 2012 |
| Type | Articolo in rivista |
| DOI | 10.1007/s00248-012-0068-0 |
| Authors | STABILI L., CARDONE F., ALIFANO P., TREDICI S.M., PIRAINO S., CORRIERO G., GAINO E. |
| Text | 215346 2012 10.1007/s00248 012 0068 0 ISI Web of Science WOS WOS 000309131700021 BENTHIC SUSPENSION FEEDERS MASS MORTALITY MARINE SPONGE EXTRACELLULAR PRODUCTS Epidemic Mortality of the Sponge Ircinia variabilis Schmidt, 1862 Associated to Proliferation of a Vibrio Bacterium STABILI L., CARDONE F., ALIFANO P., TREDICI S.M., PIRAINO S., CORRIERO G., GAINO E. IAMC CNR, UOS Taranto DiSTeBA Universita del Salento, Universita di Bari, Dipartimento Biologia Animale ed Ambientale Universita di Perugia, Dipartimento Biol Cellulare Ambientale In recent years, several episodes of mass mortality of sessile epibenthic invertebrates, including sponges, have been recorded worldwide. In the present study, we report a disease event on Ircinia variabilis recorded in September 2009 along the southern Adriatic and Ionian seas Apulian coast , with the aim to quantify the mortality incidence on the sponge population, to investigate the effect of the disease on the sponge tissues and to assess whether the disease is associated with vibrios proliferation. The injured sponges showed wide necrotic areas on the surface or disruption of the body in several portions. Necrotic areas were whitish and often were covered with a thin mucous coat formed by bacteria. In the most affected specimens, sponge organisation resulted partial or complete loss, with the final exposure of the dense skeletal network of spongine fibres to the environment. The results of microbiological cultural analysis using in parallel Marine Agar 2216 and thiosulphate/citrate/bile salts/sucrose agar demonstrated that, in affected specimens, vibrios represented 15.8 % of the total I. variabilis surface culturable bacteria. Moreover, all the isolated vibrios, grown from the wide whitish areas that characterize the surface of the diseased sponges, were identified, and their assignment to the Vibrio rotiferianus was consistent with phylogenetic analysis and data of morphological, cultural and biochemical tests. Studies on V. rotiferianus have shown that its pathogenicity, with respect to various aquatic organisms, is higher than that of Vibrio harveyi. The factors triggering the disease outbreak in Ircinia variabilis populations remain unclear. At present, we can hypothesize the involvement in the disease of a synergetic mechanism that, under stressful physiological conditions high temperature, elevated nutrients and reduced water flow , induces sponge pathogens, in our case V. rotiferanius, to become virulent, making sponges unable to control their proliferation. Additional studies are needed to understand the etiological processes as well as the factors involved in sponges recovering fromthis epidemic event allowing themto face mass mortality. A drastic reduction of sponge specific representatives could have marked a negative impact on the environmental health on account of their role in the sea remediation processes as filter feeding organisms. 64 Published version Articolo in rivista Springer Verlag, 0095 3628 Microbial ecology Microbial ecology Microb Ecol Microbial ecology. loredana.stabili STABILI LOREDANA TA.P04.029.002 Utilizzazione di biomasse e sostanze attive da organismi marini biotecnologie per loo sviluppo di nuovi bio materiali e composti bioattivi |
