Search Results (5)

Marine invertebrates, such as sponges, corals, mollusks and sea squirts, are appropriate climate-change descriptors on sublittoral rocks. The present study assesses the diversity, relative abundance and health condition of epibenthic invertebrates inhabiting sublittoral rocky habitats within the Natura 2000 network (Chalkidiki, north Aegean), after the 2021 marine heatwaves. Samplings were made with non-destructive techniques in autumn 2021 by diving along vertical belt transects (up to 30 m). Fourteen stations were surveyed, revealing 56 macroscopic invertebrates, 16 algae and 15 reef-associated fishes. Richness showed increased values at the deepest and steepest cliffs. Reefs were the dominant habitat type, hosting different facies of infralittoral algae and coralligenous biocenoses. Three algal (Halimeda tuna, Peyssonelia squamaria, Lithophyllum strictiforme) and 12 invertebrate (Aplysina aerophoba, Chondrilla nucula, Chondrosia reniformis, Ircinia variabilis, I. oros, Sarcotragus foetidus, Spongia officinalis, Balanophyllia europaea, Cladocora caespitosa, Pinna nobilis, Spondylus gaederopus, Microcosmus sabatieri) species were found in partial or full necrosis. According to relevant data collected about 20 years ago, the biota had higher diversity without signs of necrosis. Sarcotragus foetidus, I. variabilis, B. europaea, C. caespitosa and S. gaederopus were the most affected by necrosis species over the surveyed area. They represent appropriate climate change descriptors to assess the resilience of Mediterranean MPAs, being priority species in marine conservation. Full article

This study presents the first comprehensive checklist of Porifera along the Libyan coast, integrating historical data from grey and published literature with new records obtained from recent field surveys. Despite the historical relevance of sponge fisheries in Libya, knowledge of sponge diversity in the region remains remarkably fragmented. To address this gap, underwater surveys were conducted at the Gara and Bsis Marine Protected Areas (MPAs), where sponge specimens were collected and identified through morphological analyses. Previous studies documented 44 sponge species in Libya, with Demospongiae as the dominant class. The recent field surveys at the Gara and Bsis Island MPAs documented a total of nine species, including two new records for Libyan waters, Chalinula renieroides and Ircinia variabilis, both identified from the Gara MPA. These new records expand the known distribution of Mediterranean demosponges and contribute to a better understanding of their biogeographic patterns in an understudied region. Overall, the updated checklist comprises 46 species and represents an essential baseline for the Libyan coast. This study underscores the importance of future monitoring, emphasizing the expansion of systematic surveys, the investigation of diverse habitats, and the integration of molecular approaches to ensure a comprehensive understanding and effective conservation of Libya’s marine sponge heritage. Full article

Solid phase microextraction (SPME) coupled to gas chromatography-mass spectrometry (GC-MS) was employed for the headspace determination of the volatile organic fraction emitted by two of the most common Mediterranean demosponges, Ircinia variabilis and Sarcotragus spinosulus, and of indole and some biogenic amines released by sponges in an aqueous medium. A total of 50/30 µm divinylbenzene/carboxen/polydimethylsiloxane and 75 µm carboxen/polydimethylsiloxane fibers were used for the headspace extraction of low molecular weight sulfur compounds from a hermetically sealed vial containing sponge fragments, while the direct immersion determination of indole and biogenic amines was performed. The biogenic amines were extracted after in-solution derivatization with isobutyl chloroformate. All analytical parameters (linearity, limits of detection, and quantification, precision, and recovery) were evaluated for indole and biogenic amines. SPME-GC-MS proved to be a reliable means of highlighting the differences between molecules released by different sponges, principally responsible for their smell. The combined approaches allowed the identification of several volatile compounds in the headspace and other molecules released by the sponges in an aqueous medium, including indole and the BAs cadaverine, histamine, isobutylamine, isopentylamine, propylamine, 2-phenylethylamine, putrescine and tryptamine. The results obtained represent a further contribution to the picture of odoriferous molecules secreted by sponges. Full article

The fungus Aspergillus tubingensis (strain OY907) was isolated from the Mediterranean marine sponge Ircinia variabilis. Extracellular extracts produced by this strain were found to inhibit the growth of several fungi. Among the secreted extract components, a novel anhydride metabolite, tubingenoic anhydride A (1) as well as the known 2-carboxymethyl-3-hexylmaleic acid anhydride, asperic acid, and campyrone A and C were purified and their structure elucidated. Compound 1 and 2-carboxymethyl-3-hexylmaleic acid anhydride inhibited Neurospora crassa growth (MIC = 330 and 207 μM, respectively) and affected hyphal morphology. We produced a N. crassa mutant exhibiting tolerance to 1 and found that a yet-uncharacterized gene, designated mas-1, whose product is a cytosolic protein, confers sensitivity to this compound. The ∆mas-1 strain showed increased tolerance to sublethal concentrations of the chitin synthase inhibitor polyoxin D, when compared to the wild type. In addition, the expression of chitin synthase genes was highly elevated in the ∆mas-1 strain, suggesting the gene product is involved in cell wall biosynthesis and the novel anhydride interferes with its function. Full article