Distribution of benthic foraminifera in Upper Quaternary sediments of the Deryugin Basin (Sea of Okhotsk)

Benthic foraminifera are investigated in sediment core LV28-34-2 (53°51.971′N, 146°47.499′E, sea depth 1431 m, core length 965 cm). The distribution of foraminifera is studied in coarse-grained (>0.125 mm) sediment fractions of 191 samples taken with a step of 5 cm. The core covers the interval from oxygen isotope stage (OIS) 6 up to the Holocene. The foraminiferal assemblages of the penultimate (OIS 6) and last (OIS 5d-2) glaciations are characterized by low abundances and prevalence of Uvigerina auberiana. The specific structure of the OIS 6 assemblages differs from the last glaciation ones by the mass presence of Cassidulina teretis, which characterizes low temperatures and a high influx of organic matter to the sea floor. The major factor responsible for the weak development of benthic foraminifers during the glacial time is the deficiency of food resources. The foraminiferal assemblage of the interglacial optimum (OIS 5e) is composed of both calcareous and agglutinated species (Martinottiella communis).The inflow of Pacific waters was probably more intensive, the bioproductivity was higher, and the critical carbonate compensation depth was shallower at that time than during the glaciations. During the deglaciation, the quantity and structure of the foraminiferal assemblages reflected two pulses of warming (terminations 1B and 1A) with an intervenient cooling event (Younger Dryassic). The assemblages of warm periods were characterized by exclusively high foraminiferal abundances, which sharply decreased during the Younger Dryassic cooling. The specific structure of the foraminiferal assemblage during deglaciation was relatively uniform, being composed of only calcareous taxa typical of highly productive areas of the ocean. The paleoenvironmental conditions were similar to the conditions of the interglacial optimum (OIS 5e), although the preservation of calcareous tests is better. In the Holocene sediments, the concentration of benthic foraminifera is substantially lower than during the deglaciation, which is explainable by their dilution in the sediments by diatoms; the composition of the foraminiferal assemblages is similar to that of their glacial counterparts.     

Summer larval fish assemblages in the Southern Tyrrhenian Sea (Western Mediterranean Sea)

The purpose of this paper was to study the community structure, in terms of species composition, abundance and spatial distribution, of fish larvae in a wide coastal area of Sicily facing the Southeastern Tyrrhenian Sea, extending for 2300 km² from Cape Cefalù to the west, to Cape Rasocolmo in the east. This study analyses how species are assembled in relation to an inshore–offshore gradient and also how environmental conditions, determined by surface circulation patterns occurring in the Central Mediterranean at the local scale, determine the distribution patterns. Samples from 39 stations were collected using a 60‐cm Bongo net during an ichthyoplanktonic survey carried out in June 2006. In all, 62 taxa, representing 32 families, were identified. Cyclothone braueri (59.6%), Engraulis encrasicolus (9.2%) Lampanyctus crocodilus (4.3%) and Lampanyctus pusillus (4.1%) were the most abundant species. The results showed that the highest abundance value (14830.6 fish larvae per 10 m² sea surface) was observed in the western part of the study area. MDS, SIMPER and CCA analyses revealed well defined groups of stations and assemblages of larvae in accordance with an inshore–offshore gradient. The results of this study could have implications for the management of marine resources because the investigated area has already been identified as a nursery area for many pelagic and coastal fishes and a natural habitat for many species of high commercial interest.     

Particulate barium fluxes on the continental margin: a study from the Alboran Sea (Western Mediterranean)

Particulate biogenic barium (bio-Ba) fluxes obtained from three instrumented arrays moored in the Alboran Sea, the westernmost basin in the Mediterranean Sea, are presented in this study. The mooring lines were deployed over almost 1 year, from July 1997 to May 1998, and were equipped with sediment traps at 500–700 m depth, 1000–1200 m depth and 30 m above the seafloor (1000–2200 m). The results obtained support the growing body of evidence that the relationship between particulate bio-Ba and Corg throughout the water column in margin systems is clearly different from this relation in the open ocean. In the Alboran Sea, the annual averaged bio-Ba fluxes range from 0.39 to 1.07 μmol m⁻² day⁻¹, with mean concentrations of 1.31–1.69 μmol g⁻¹ and bio-Ba/Corg ratios lower than in the open ocean. The low bio-Ba values obtained also indicate that calculating bio-Ba is extremely sensitive to the detrital Ba/Al ratio of each sample. The lithogenic Ba fraction in the Alboran Sea continental margin area contributes between 24% and 85% of the total Ba. Increased bio-Ba export efficiency was observed after periods of high primary productivity and suggests that the processes limiting the bio-Ba formation in the study area relate to settling dynamics of organic matter aggregates. Furthermore, the ballasting effect of the abundant lithogenic and carbonate particles may limit decomposition of organic matter aggregates and enhance the transfer of particles rich in Corg and relatively poor in bio-Ba to the deep seafloor. Lateral input of freshly sedimented biogenic material, including particulate bio-Ba, has been observed on the lower continental slope in the western Alboran Sea. These observations emphasize that the use of the bio-Ba as a proxy of export productivity from the surface ocean must be used cautiously in highly dynamic environments such as those in the Alboran Sea.     

Contourites offshore Pantelleria Island (Sicily Channel, Mediterranean Sea): depositional, erosional and biogenic elements

High-resolution seismic reflection profiles and multibeam bathymetry data collected in 2006 and 2008 around Pantelleria Island show the widespread occurrence of contourite drifts and erosional elements ~30?km from the narrowest part (~145?km) of the Sicily Channel, where water masses from the Eastern Mediterranean flow towards the Western Mediterranean. The contourite drifts are rather small (up to 10?km long and 3.3?km wide), at water depths of ~250?C750?m. Most are elongated separated drifts with quite well-developed moats and crests, aligned roughly parallel to the regional bathymetric contours. Erosional elements include abraded surfaces, moats, scours and sub-circular depressions. In addition, a wide sector of the seafloor adjacent to a seamount located SW of Pantelleria Island is characterized by numerous biogenic build-ups colonized by deep-water corals (Madrepora oculata). The spatial distribution of sediment drifts, erosional features and biogenic build-ups suggests an origin from a north-westward-flowing bottom current, in this case the outflow of Levantine Intermediate Water and transitional Eastern Mediterranean Deep Water via the Sicily Channel. These findings for the Pantelleria offshore sector demonstrate that contourite processes are able to concentrate a high variety of closely spaced depositional and erosional features even in small areas (in this case, about 2,000?km²). This Pantelleria focusing can plausibly be related to a particular configuration of the prevailing bottom-current regime in complex interaction with an uneven bathymetry shaped mainly by tectonic and volcanic activity. The distribution of bottom currents seems to be strongly influenced by morphological features ranging from major seabed obstacles, such as the Pantelleria volcanic complex and the so-called southwest seamount, to smaller-scale escarpments and banks. This is consistent with previous findings for Mediterranean and other settings characterized by neotectonics and large topographic features.     

Live (stained) benthic foraminifera in the Whittard Canyon, Celtic margin (NE Atlantic)

Living (Rose Bengal stained) benthic foraminifera were investigated at 18 deep-sea stations sampled in the Whittard Canyon area (NE Atlantic). The stations were positioned along 4 bathymetric transects ranging from 300 to 3000 m depth: two along the main canyon axes (Western and Eastern branches) and two along adjacent open slopes (Western and Eastern slopes). The aim of this study was to assess changes of foraminiferal standing stock, composition and microhabitat in relation to the physico-chemical conditions prevailing at and below the sediment-water interface in various canyon and open-slope environments. Minimal oxygen penetration depths and maximal diffusive oxygen uptakes were recorded at upper canyon stations, suggesting a high mineralisation rate. This is confirmed by the high phytopigment concentrations measured in the sediment of the upper canyon axes. Foraminiferal abundance was positively correlated with diffusive oxygen uptake and phytopigment concentration in the sediment. This suggests a control of organic matter fluxes on the foraminiferal communities. Foraminiferal abundance was generally higher along the canyon axis compared to open-slope sites at comparable water depths. The species composition varied with water depth along all four transects, but was also different between canyon branches and adjacent slopes. The silty/sandy intercalations at many of the deeper canyon stations may have been rapidly deposited by fairly recent gravity flows. At station 51WB (3002 m), the faunal characteristics (strong dominance, shallow infaunal microhabitats) suggest that the foraminiferal community is in an early state of ecosystem colonisation after these recent sedimentation events, which would have supplied the important amounts of phytopigments.     

Temporal changes in the structure of the crustacean decapod assemblages associated with Cymodocea nodosa meadows from the Alboran Sea (Western Mediterranean Sea)

The decapod assemblages associated with two shallow meadows of Cymodocea nodosa, located in the same geographical area (Southern Spain) but on different substrates and with different patch size, have been analyzed. They display similar structure (diversity indices not significantly different), without a clear relation of richness and abundances to patch size, and with the same dominant species (the family Hippolytidae and, in particular, Hippolyte leptocerus are characteristic of this habitat). The composition of both crustacean assemblages is influenced by species that are common in neighbouring habitats. Therefore the connectivity among them is an important factor in the qualitative and quantitative structure of these decapod communities. Species richness appears to be higher than in Cymodocea meadows elsewhere in the Mediterranean and Atlantic at a similar depth, perhaps as a consequence of the biogeographical location and the high diversity and connectivity with surrounding biotopes. High evenness values are the result of the structure and location of these meadows, which are fragmented and interspersed with other biotopes (sandy and rocky bottoms), resulting in an ‘ecotone effect’. On the other hand, the structures of the decapod assemblages differ significantly according to sampling period. The abundance and species richness are both related to plant phenology and the dominant species present a positive correlation with the number of leaves per shoot. The maximum abundance of many species is coincident with the greatest seagrass development (spring – summer), which provides more resources (surface, biomass, protection, food). Therefore, seasonality is linked to plant life cycle, but also to the interrelationships and biology of the species, which are adapted and specialized to the environmental features of these shallow habitats.     

Comparison of benthic foraminifera inside and outside a sulphur-oxidizing bacterial mat from the present oxygen-minimum zone off Pakistan (NE Arabian Sea)

Assemblages of live (Rose-Bengal-stained) and dead benthic foraminifera and stable oxygen and carbon isotopic composition of live benthic foraminifera were studied in and outside a bacterial mat composed of the large sulphur-oxidizing bacteria Thioploca and Beggiatoa from the oxygen-minimum zone off Pakistan (NE Arabian Sea). Two cores from the same Multicorer retrieved a bacterial mat and ambient sediment. The dominant species (Globobulimina affinis, G. turgida, Bolivina pacifica, B. pseudopunctata, Uvigerina peregrina and Buliminella tenuata) in both cores are characteristic for dysoxic oxygen minimum zone conditions. The most significant difference between the two cores is the reduced number of stained benthic foraminifera (SBF) in the top 0.5 cm of the bacterial mat. Faunal densities of stained species are more than four times higher in the sediment surface sample (0–0.5 cm) outside the bacterial mat, at a distance of only 1.5 m. All stained species, however, observed outside the Beggiatoa/Thioploca mat were also observed in the core with the mat. Two species, Virgulinella fragilis and Bolivina dilatata, occur exclusively in the core with the bacterial mat. The diversity within the bacterial mat core is thus slightly higher than outside. Furthermore, the abundances of the species Buliminella morgani, B. tenuata and Alliatina primitiva are substantially higher in the bacterial mat than outside. Globobuliminids, on the other hand, seem to prefer the conditions outside the bacterial mat and are five times more frequent in the core taken outside the bacterial mat. Benthic foraminifers inhabit a broader microhabitat range outside the bacterial mat (∼5 cm) than within (3.5 cm). A marked decrease in SBF abundances was observed at the level of a black sulphur-rich layer which is interpreted to mark the shallow redox front below the bacterial mat. Stable carbon isotope analyses on live benthic foraminifera do not support a relation of the investigated Beggiatoa/Thioploca mat to a constant or seasonal seepage of methane at the continental slope off Pakistan. Surprisingly, however, stable oxygen isotope values of many species and especially of U. peregrina decrease with depth, which calls into question the suitability of U. peregrina as a recorder of bottom-water δ¹⁸O.     

Habitat Selection and Ecology of Two Speleophilic Gobiid Fishes(Pisces: Gobiidae) from the Western Mediterranean Sea

The life habits and microhabitat selection of speleophilic gobiid fishes were investigated on the Balearic Island of Ibiza (western Mediterranean Sea). Corcyrogobius liechtensteini (Kolombatović, 1891) was the most frequent species within submarine crevices, cavities and caves. Didogobius splechtnai Ahnelt & Patzner, 1995 co-occurred with C. liechtensteini in several cases but showed a clear spatial separation based on a different microhabitat preference. The microhabitat selection of both species was confirmed by habitat-choice experiments in anaquarium. Corcyrogobius liechtensteini was frequent in depths between 5 m and 25 m and attained abundances of 14.2 individuals · m⁻². This species inhabited the ceilings and upper parts of the walls within the caves. D. splechtnai was mainly found between 7 m and 11 m and showed abundances of approximately 2 indivi-duals · m⁻². This species occupied the fine sediment bottoms in the innermost parts of crevices and caves. The growth and the maximum age of both species were determined by length-frequency distributions. The overall sex ratio from catches of three different years are given for C. liechtensteini .     

Acoustic monitoring of gas emissions from the seafloor. Part II: a case study from the Sea of Marmara

A rotating, acoustic gas bubble detector, BOB (Bubble OBservatory) module was deployed during two surveys, conducted in 2009 and 2011 respectively, to study the temporal variations of gas emissions from the Marmara seafloor, along the North Anatolian Fault zone. The echosounder mounted on the instrument insonifies an angular sector of 7° during a given duration (of about 1 h). Then it rotates to the next, near-by angular sector and so forth. When the full angular domain is insonified, the “pan and tilt system” rotates back to its initial position, in order to start a new cycle (of about 1 day). The acoustic data reveal that gas emission is not a steady process, with observed temporal variations ranging between a few minutes and 24 h (from one cycle to the other). Echo-integration and inversion performed on the acoustic data as described in the companion paper of Leblond et al. (Mar Geophys Res, 2014), also indicate important variations in, respectively, the target strength and the volumetric flow rates of individual sources. However, the observed temporal variations may not be related to the properties of the gas source only, but reflect possible variations in sea-bottom currents, which could deviate the bubble train towards the neighboring sector. During the 2011 survey, a 4-component ocean bottom seismometer (OBS) was co-located at the seafloor, 59 m away from the BOB module. The acoustic data from our rotating, monitoring system support, but do not provide undisputable evidence to confirm, the hypothesis formulated by Tary et al. (2012), that the short-duration, non-seismic micro-events recorded by the OBS are likely produced by gas-related processes within the near seabed sediments. Hence, the use of a multibeam echosounder, or of several split beam echosounders should be preferred to rotating systems, for future experiments.     

Oscarella balibaloi,a new sponge species (Homoscleromorpha: Plakinidae) from the Western Mediterranean Sea: cytological description,reproductive cycle and ecology

A new homoscleromorph sponge species was observed for the first time in 2002 along the coast of Provence (France) and since then, several investigations have been implemented. The new homoscleromorph species is devoid of skeleton and it is thus related to the Oscarella genus. Oscarella balibaloi sp. nov. has been found in several littoral submarine caves of the Western Mediterranean Sea (France and Spain). After several years of monitoring, we show that this sponge is becoming abundant in several locations. The species has a peculiar habit, often overgrowing massive sponges, gorgonians or some erected bryozoans. Oscarella balibaloi sp. nov. is thinly encrusting, with an irregular morphology, lobate surface, and soft and very slimy consistency. Its color is white to orange. At the cytological level, this new species is characterized by three distinct types of cells with inclusions in its mesohyl: one with vacuoles and the others with paracrystalline inclusions. The reproduction pattern is very similar to other Oscarella species. We also present a specific metabolic fingerprint and compare it to that of other Mediterranean Oscarella species.     

The ecology and distribution of benthic foraminifera at the Håkon Mosby mud volcano (SW Barents Sea slope)

To investigate a possible influence of submarine methane seepage on benthic foraminiferal communities, Rose Bengal stained (“live”) and empty tests of benthic foraminifera were studied from the sediment surface down to 15 cm sub-bottom depth of 12 sites at the Håkon Mosby mud volcano (HMMV). In addition, one reference site well away from the seep sites, but from similar water depths and the same general hydrographic setting was occupied for comparison. The HMMV is located at 1265 m water depth on the SW Barents Sea continental slope. Distinct living foraminiferal associations at the HMMV are linked to specific sedimentary, microbial, and macrofaunal habitats. In the center of the crater, and in crater areas completely covered by bacterial mats, Cassidulina reniforme is the only, albeit rare, living species. Below the top few millimeters, sediments are anoxic and devoid of living specimens. At the rim of the mud volcano, at sites densely populated by pogonophoran tube worms, three benthic foraminiferal associations are found; (i) a Fontbotia wuellerstorfi–Lobatula lobatula association living attached to the upper parts of pogonophoran tubes, which protrude into oxic water, (ii) a diverse Cassidulina neoteretis association populating dysoxic sediments of the surface centimeter, and (iii) a species-poor Bolivina pseudopunctata association colonizing the subsurface sediments down to four centimeters. Generally, we did not find endemic or seep indicative species or associations at the HMMV. However, the HMMV live faunas dominated by B. pseudopunctata are not found at the reference site nor are they described from comparable water depths and environments without gas seepages from the Norwegian-Greenland Seas.In the center and outer rim of the mud volcano, a C. neoteretis–Reophax guttifer dead association, similar to the one at the reference site, characterizes an assemblage of strongly corroded and partly displaced tests. At bacterial mat sites, a C. reniforme dead association corresponds to the living one. Thus both the living and the dead associations are indicative of a specific bacterial mat environment at the HMMV.     

Crustacean decapod assemblages associated with fragmented Posidonia oceanica meadows in the Alboran Sea (Western Mediterranean Sea): composition,temporal dynamics and influence of meadow structure

The decapod assemblage associated with a Posidonia oceanica meadow located near its western limit of biogeographic distribution was studied over an annual cycle. Fauna samples were taken seasonally over a year (five replicates per season) in two sites located 7 km apart, using a non‐destructive sampling method (airlift sampler) for the seagrass. The dominant species of the assemblage, Pisidia longimana, Pilumnus hirtellus and Athanas nitescens, were associated with the protective rhizome stratum, which is mainly used as a nursery. The correlations between decapod assemblage structure and some phenological parameters of the seagrass shoots and wave height were negative or null, which reflects that species associated with the rhizome had a higher importance than those associated with the leaf stratum. The abundance and composition of the decapod assemblage as well as the ecological indexes displayed a seasonality trend with maximum values in summer‐autumn and minimum in winter‐spring, which were related to the seawater temperature and the recruitment periods of the dominant species. The spatial differences found in the structure and dynamics of the assemblages may be due to variations in the recruitment of the dominant species, probably as a result of the influence of local factors (e.g. temperature, currents) and the high dispersal ability of decapods, together with the patchy configuration and the surrounding habitats. The studied meadows are fragmented and are integrated within a mosaic of habitats (Cymodocea nodosa patches, algal meadows, rocky and sandy bottoms), which promotes the movement of individuals and species among them, maintaining a high species richness and evenness.     

Eastern and Western Poor Cod (Trisopterus minutus capelanus) Populations in the Mediterranean Sea: Evidence from Allozyme and Minisatellite Loci

Abstract. Nine allozyme and two minisatellite loci were used to investigate potential genetic differentiation among three samples of Mediterranean poor cod, Trisopterus minutus capelanus, from the Gulf of Lion, the Tuscan Archipelago and the Aegean Sea. Both types of markers showed consistent results, with F_ST values of 0.0262 and 0.0296 (P < 0.0015, after Bonferroni correction for multiple tests) for allozymes and minisatellites, respectively. Allele frequency heterogeneity tests between pairs of samples showed a clear separation between the two western Mediterranean samples (Gulf of Lion, Tuscan Archipelago) and the eastern one (Aegean Sea). The results indicate that at least two reproductively isolated populations of poor cod occur in the Mediterranean.     

Stable isotopes in deep-sea living (stained) foraminifera from the Mozambique Channel (eastern Africa): multispecies signatures and paleoenvironmental application

Oxygen and carbon isotopes (δ¹⁸O and δ¹³C) have been investigated in carbonate tests of deep-sea foraminifera living in the Mozambique Channel (eastern Africa) to understand how environmental constraints (e.g., organic matter, oxygenation) control the intra- and interspecific variability of isotopic signatures. 197 living individuals, including eight different species, from various microhabitats within the sediment were sorted from sediment samples gathered at two stations on the Malagasy upper slope. Results show that the δ¹⁸O values of foraminiferal taxa were not controlled by microhabitat pattern. They presented tremendous and intriguing intraspecific variability that is not explained by the classical ontogenetic effect. The δ¹³C values of infaunal foraminiferal taxa do not show a 1:1 relationship with the bottom water δ¹³C DIC and do not present a constant offset from it; instead, they appear to be mainly controlled by a microhabitat effect. The lower δ¹³C values of shallow, intermediate, and deep infaunal taxa at the deeper station compared to those seen at the shallower station reflect the enhanced exportation of sedimentary organic matter at the sediment–water interface, and its related mineralization within the upper sediments. The ?δ¹³C between shallow/very shallow infaunal species (i.e., Hoeglundina elegans, Uvigerina hispida) and intermediate/deep infaunal species (i.e., Melonis barleeanus, Globobulimina barbata) permits insight into (1) the exportation of organic matter to the seafloor and (2) the various degradation pathways for organic detritus in the benthic environments off NW Madagascar.     

The Deep-Water Peyssonnelia Beds from the Balearic Islands (Western Mediterranean)

Abstract. Peyssonnelia bed distribution on continental shelf bottoms of the Balearic Islands (Western Mediterranean) ranges from 40 to 90 m depth. Different species of Peyssonnelia dominate these bottoms and, according to multivariate techniques, two main assemblages have been distinguished: the Peyssonnelia rosa-marina beds and the Peyssonnelia sp. beds, together with some transition samples between Peyssonnelia and maërl beds. Erect red algae are always abundant. Although average yearly irradiance reaching these beds is only 6.4-0.3% of subsurface irradiance, the species richness averages 45 species per sample (1600 cm²) and mean biomass is 2835 g dw. m^-2. The high carbonate content of the living algae of these bottoms suggests that they are important contributors to the production of sediments in the Balearic continental shelf.     

青岛湾潮间带活体底栖有孔虫Ammonia aomoriensis (Asano,1951)壳体δ18O值的季节变化

近岸浅水底栖有孔虫是陆架海区古环境重建的重要手段,但是至今对其活体的研究非常缺乏。2014年6月至2015年5月对青岛湾潮间带活体底栖有孔虫Ammonia aomoriensis进行了连续12个月的采样,用虎红染色以确认活体。对壳径范围在200~550μm的活体壳体,以每增加50μm壳径为一组,进行δ18O测试。结果显示,A.aomoriensis壳体δ18O的月平均值的季节变化趋势与温度和盐度一致,与温度反相关,与盐度正相关,即青岛湾A.aomoriensis壳体δ18O值受温度和海水δ18O的影响,其壳体δ18O值表现出了很好的季节性波动。但是A.aomoriensis壳体δ18O的变化滞后于所测温度和盐度约2个月,其记录的是虫体在生长周期内在真实钙化温度下分馏所得的δ18O值。     

Long‐term sponge stranding along the shores of Sardinia Island (Western Mediterranean Sea)

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.     

Colonisers of the dark: biostalactite‐associated metazoans from “lu Lampiùne” submarine cave (Apulia,Mediterranean Sea)

Metazoan/microbial bioconstructions, or biostalactites (BSTs), discovered in submarine caves of Apulia c. 20 years ago—and later found in several shallow‐water Mediterranean caves—are receiving increasing attention in the last years. Examination of a single BST from the “lu Lampiùne” cave (Apulia), at the limit between the Adriatic and the Ionian seas, has been addressed for the first time in this paper. The BST started growing at c. 6,000 years ago with a rapid accretion of large‐sized serpulids (Protula), slowing down since about 3,000–4,000 years ago with a shift in main bioconstructors, probably caused by environmental changes. The present‐day community on the outer BST surface is dominated by skeletonised epibionts, mostly small‐sized serpulids, bryozoans and foraminifers, which contribute carbonate to the BST growth, by encrusting sponges, and by a few endobionts, including boring bivalves and insinuating sponges. New data remarkably increase biodiversity known for the “lu Lampiùne” cave and the cave habitat in the region. Thirty‐five taxa (16 bryozoans, 10 serpulids, 3 brachiopods, 2 foraminifers, 2 sponges, 1 bivalve and 1 cirriped) are recorded for the first time from Apulian marine caves, highlighting the need for further research in the area. In addition, the BST‐associated community seems to differ from those of individual BSTs from other Mediterranean caves, revealing the individuality of these communities.