Sponge community variation along the Apulian coasts (Otranto Strait) over a pluri-decennial time span. Does water warming drive a sponge diversity increasing in the Mediterranean Sea? (original) (raw)
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Shallow-water sponge grounds along the Apulian coast (central Mediterranean Sea)
Marine Biodiversity, 2020
Sponge grounds are complex three-dimensional benthic habitats dominated by sponges. These sponge-dominated assemblages have been reported worldwide, from the intertidal zone to the deep sea. In shallow euphotic waters, dense sponge aggregations have been mainly found in tropical areas, and their presence is in some cases related to environmental degradation and coral decline. The Mediterranean Sea is globally recognised as a biodiversity hotspot, where light-exposed rocky reefs are typically dominated by photophilous algae. However, high local anthropogenic pressures, coupled with climate change, are leading to the reorganisation of benthic communities and the occurrence of regime shifts in several areas. Here we report the first description of unusual, shallow-water sponge grounds in Mediterranean light-exposed rocky reefs, in an area previously impacted by the destructive date-mussel fishery. These assemblages, found along the Apulian coast (central Mediterranean Sea), are now (2017) characterised by a mean coverage of sponges ranging between 3% and 33%, with maximum values up to 85%. Variation in the structure of assemblages and in the abundance of individual taxa between depths has been tested by multivariate and univariate techniques. The spatial characterisation has been complemented with the taxonomic analysis of the sponge assemblages, which resulted in the identification of 14 sponge taxa. These findings are compared with results of previous research in the same area and discussed with particular reference to the potential variables involved in sponge dominance and spatial distribution in the present system and elsewhere.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2017
Changes occurring over a pluri-millennial span of time (6207-1767 yr B.P.) within the sponge assemblages present in two coralligenous pillars, about 60 cm high, collected at 20 m depth, inside the Marine Protected Area of Porto Cesareo (Ionian Sea, Mediterranean Sea) have been studied. The sponge diversity has been analyzed at generic level, using as a proxy the siliceous spicules trapped into the sediment present into the crevices of these bioherms. In total, 41 genera of ancient demosponges were identified. The modern sponge fauna of these coralligenous pillars totals 31 genera, 15 of them shared with the ancient assemblages. The sponge biodiversity during the considered span of time showed critical changes, with remarkably similar trends in both the considered pillars. Tentatively, these changes were attributed to different climatic events that affected the Mediterranean area during the studied time span. The number of genera, 6000 yr B.P., was low and increased between 5500 and 4000 yr B.P. During the Late Bronze Age (4000-3000 yr B.P.), a new decrease was recorded, followed by a further increase around 2000 yr B.P. Afterwards, the bioherms stopped growing and no more siliceous spicules were trapped. From a biogeographic point of view, the wide presence of spiny microrhabdose microscleres belonging to the genus Alveospongia (Heteroxyidae), recently described from the tropical Atlantic and still unknown in the Mediterranean Sea, has to be underlined. In addition the trends recorded over time in the Ionian Sea match with those already observed in the Ligurian Sea. The comparison between the past periods and the modern one shows evident changes in biodiversity in both areas. The sharp variations of the seawater temperature-occurred in both the Mediterranean regions-could have driven the changes in genus richness. Using sponges to interpret the effects of climate changes can be a profitable strategy to unravel long term changes in biodiversity, supporting future predictions.
Hydrobiologia, 2012
Recognizing and understanding presentday biodiversity and biogeographical patterns and how these relate to contemporary and past climate is pivotal to predict the effect of future climate on marine biodiversity and promote adequate conservation policies. Sponges constitute an important and dominant component of the marine benthos and are therefore an excellent model group for such investigations. In this study, we assessed the diversity patterns and the Guest editors: M. Maldonado, X. Turon, M. A. Becerro & M. J. Uriz / Ancient animals, new challenges: developments in sponge research
Long-term turnover of the sponge fauna in Faro Lake (North-East Sicily, Mediterranean Sea)
Italian Journal of Zoology
The paper focuses on the long-term taxonomic composition and distribution of the shallow-water sponge fauna from the meromictic-anchialine coastal basin Faro Lake (Southern Italy), comparing recent qualitative field data with literature data over a 50-year period. The Faro Lake shallow water currently hosts 24 conspicuous species of Porifera belonging to 21 genera, 18 families, eight orders, three subclasses and two classes, i.e. Demospongiae (23) and Calcarea (one). The comparison between the present and past status of the sponge fauna showed a high turnover, with 15 new colonizers and only nine persistent species. Thirteen species reported in the literature are missing, suggesting the occurrence of remarkable changes in the faunal composition during the last 50 years. The analysis of the geographic distribution of each species allowed us to outline the prevalent North Atlantic affinity of the sponge community. Worthy of note is the new record of the alien calcareous sponge Paraleucilla magna of cryptogenic origin.
Long‐term sponge stranding along the shores of Sardinia Island (Western Mediterranean Sea)
Marine Ecology, 2019
The taxonomic richness and geographic distribution of sponges stranded along Sardinian shores were investigated in the long term by means of a revisited ancient sampling method in order to support a comprehensive species inventory. Almost all stranded species were Keratosa (n = 20), plus 6 species of other Demospongiae taxa. Dictyoceratida were dominant, with 6 genera and 19 species of the families Irciniidae, Spongiidae and Thorectidae: 9 Mediterranean endemics, 7 Atlanto-Mediterranean and 3 widespread species. Regarding Dendroceratida, only the genus Spongionella was found. Some species (n = 8) were recorded for the first time in circum-Sardinian seas. A high percentage (54.3%; 19 out of the 35 species) of the total Mediterranean Dictyoceratida fauna was recorded, including the most endangered Mediterranean species, that is of the genera Spongia and Hippospongia. Hippospongia communis, Ircinia variabilis, Spongia zimocca and Spongia officinalis were the most common species. Morphotraits of rare and/or poorly known species were investigated by scanning electron microscopy (SEM). Comparison among Sardinian sectors, and between Sardinian and adjacent seas, revealed a high similarity of stranded Dictyoceratida, despite the fact that the data from Tyrrhenian and Balearic-Catalan seas were collected mainly from SCUBA records. The cost-effective sampling method used in the present study seems appropriate to the gross qualitative monitoring of coastal areas (e.g. large unexplored Northern African coasts), in order to assess the conservation status of Mediterranean Keratosa species. The wide distribution of all Mediterranean bath sponge species indicates their good conservation status in circum-Sardinian seas, a datum that could usefully support the future management of this bioresource, particularly in protected areas.
PloS one, 2017
This paper concerns the changes occurred over both decennial and millennial spans of time in a sponge assemblage present in coralligenous biogenic build-ups growing at 15 m depth in the Ligurian Sea (Western Mediterranean). The comparison of the sponge diversity after a time interval of about 40 years (1973-2014) showed a significant reduction in species richness (about 45%). This decrease affected mainly the massive/erect sponges, and in particular the subclass Keratosa, with a species loss of 67%, while the encrusting and cavity dwelling sponges lost the 36% and 50%, respectively. The boring sponges lost only one species (25%). This changing pattern suggested that the inner habitat of the bioconstructions was less affected by the variations of the environmental conditions or by the human pressures which, on the contrary, strongly affected the species living on the surface of the biogenic build-ups. Five cores extracted from the bioherms, dating back to 3500 YBP, allowed to analyse...
Sponges in a Changing Climate: Survival of Agelas oroides in a Warming Mediterranean Sea
Frontiers in Marine Science, 2020
Sponges hold a key role in benthic environments, and specifically in the Mediterranean Sea. Past events of mass mortality in sponge communities have been linked to extended periods of high-temperature anomalies, yet it is unknown how a gradual change, such as the constant rise in global seawater temperatures, will affect biodiversity. Here we present a case study of Agelas oroides, a common massive sponge in the Mediterranean Sea, found at a wide depth range of 1–150 m. Last documented in the 1970s, A. oroides was considered lost from the Israeli coastal fauna. However, its recent rediscovery in mesophotic depths, where environmental conditions are stable, provided an opportunity to examine whether it can survive the present conditions in the shallow Israeli coast – where temperatures increased by 3°C during the past 60 years, while the nutrients concentration decreased following the damming of the Nile River. To test this hypothesis, A. oroides individuals were collected during win...
Spatial and temporal distributions of the sponge fauna in southern Italian lagoon systems
The present work focused on the taxonomic composition, spatial distributions, and temporal distributions of the sponge fauna from the main lagoon systems of southern Italy: Lesina, Varano, Taranto, Alimini, Faro, Ganzirri, Tindari and Marsala. Overall, 62 sponge species were recorded, belonging to the classes Demospongiae (52 species), Calcarea (8) and Homoscleromorpha (2). All the lagoon systems studied hosted sponges, even if with marked differences. Species richness varied from one (Lesina) to 45 (Marsala). A large number of the species recorded during this study (52%) was found only at a single site, whereas a species only (Halichondria (H.) panicea) was present in all the environments studied. Sponges colonised all available substrates. Salinity was the ecological factor that best explained the spatial distribution of sponges, even though the wide heterogeneity of sponge assemblages, strongly suggests an important role of stochastic factors acting on pre-and post-settlement phases. Comparison of the present data with lists available from the literature shows that sponge assemblages from most of the studied lagoons were quite persistent. However, in some of the lagoons remarkable extinction processes, probably related to massive and prolonged anthropogenic pressures, have contributed to large changes in the sponge patterns.
2013
The Mediterranean coralligenous substratum is a hard bottom of biogenic origin, mainly composed of calcareous algae, growing in dim light conditions. Sponges are among of the most representative taxa of the coralligenous assemblages, with more than 300 recorded species of different habits: massive, erect, boring and insinuating. When sponges die, their siliceous spicules remain trapped in the biogenic concretion, offering the opportunity to describe the coralligenous spongofauna over a very long span of time, virtually dating back to a large part of the Holocene period. The data reported here were obtained from core samples collected from four coralligenous concretions. Each block was collected in a different locality of the Ligurian Sea: Santo Stefano Shoals, Bogliasco, Punta del Faro (Portofino Promontory) and Punta Manara. Radiocarbon age determinations indicate for these conglomerates a maximal age between 1600 and 3100 years. The spicules trapped in the cores show deep dissolution marks in the form of circular holes on their surface or present an enlargement of the axial canal. However, their original shape, generally intact, suggests the absence of mechanical injuries and allows a tentative identification at the species level. The analysis of these old spicules reveals an ancient sponge assemblage composed of 30 recognisable species. This indicates that almost one half of the sponge community today settled on coralligenous substrata has been present in the conglomerates for their entire existence.
The European Zoological Journal, 2018
In the last few decades, macrobenthic community structures and their species abundances have shown significant changes in the Mediterranean Sea, whose causes were attributed to anthropogenic activities and to global warming effects. The Mediterranean sponges have shown a peculiar sensitivity to these changes: the populations of some species showed significant decreases, while others, more thermophilous, increased. Therefore, sponges may be a good proxy for evaluating the effects of environmental changes. Thanks to the observations conducted by Sarà about 55 years ago, a comparative analysis of the sponge populations present within two semi-submerged caves in the Ligurian Sea was possible. The two sponge assemblages re-studied in 2016 showed an increase in terms of specific richness and a significant change in their structural aspects, since the three-dimensional growth forms were mostly replaced by two-dimensional ones, a process observed also in other littoral communities. Consequently, the sponge communities inside the semi-submerged caves may be considered poorly resilient: the massive sponges were hit by the positive thermal anomalies occurring in the Ligurian Sea in the last decade and were replaced by encrusting forms, within a possible phase of cave recolonisation.