Cladocora Caespitosa Research Articles

Unexpected and Extraordinarily Shallow Coralligenous Banks at the Sinuessa Site, a Heritage of the Campania Coast (SW Italy, Mediterranean Sea)

Coralligenous bioconstructions are biogenic calcareous formations developing at low irradiance on littoral rocky cliffs or on the deeper sub-horizontal bottom in the Mediterranean Sea. Unusually shallow coralligenous banks on the sandy coast of Sinuessa (Mondragone City, Gulf of Gaeta, SW Italy) were investigated. Their communities and the surrounding biogenic detritus were characterized. Geophysical and acoustic data revealed the presence of coralligenous banks between 7.5 and 15 m depth, showing constant thickness and sub-horizontal geometry, incised by sub-perpendicular channels. Sediment deposits ranging from silty sands to bioclastic gravel occur in the area. The biogenic detritus of the soft bottom sampled around the coralligenous banks is highly heterogeneous. Through the thanatocoenosis analysis of macrozoobenthos, different biocenoses were detected, among which the coralligenous and photophilic habitats are mainly represented, followed by the well-calibrated fine sands and the relit sands. A total of 16 different species and 10 epimegabenthic morphological groups (MGs) were detected on the coralligenous banks, of which 4 are included in European regulation for threatened species. The density of epimegabenthic organisms has an average of 10.34 ± 5.46 individuals or colonies/100 m2. Cladocora caespitosa is the dominant species, with a height of 17 ± 5 cm. This and other structuring species (SS) were larger in size in the sampled sites than in the literature data. Overall, coralligenous had a “medium” health status, with 52% of the individuals or colonies in healthy conditions, compared to 47% with epibiosis phenomena and 1% with entanglement. Longlines were the most common anthropogenic litter, with a density of 2/100 m2. Ad hoc monitoring programs and conservation measures would be desirable to protect and guarantee the well-being of these sensitive and rare shallow bioconstructions.

Elevated heterotrophic capacity as a strategy for Mediterranean corals to cope with low pH at CO2 vents.

The global increase in anthropogenic CO2 is leading to ocean warming and acidification, which is threatening corals. In Ischia, Italy, two species of Mediterranean scleractinian corals-the symbiotic Cladocora caespitosa and the asymbiotic Astroides calycularis-were collected from ambient pH sites (average pHT = 8.05) and adjacent CO2 vent sites (average pHT = 7.8) to evaluate their response to ocean acidification. Coral colonies from both sites were reared in a laboratory setting for six months at present day pH (pHT ~ 8.08) or low pH (pHT ~7.72). Previous work showed that these corals were tolerant of low pH and maintained positive calcification rates throughout the experiment. We hypothesized that these corals cope with low pH by increasing their heterotrophic capacity (i.e., feeding and/or proportion of heterotrophically derived compounds incorporated in their tissues), irrespective of site of origin, which was quantified indirectly by measuring δ13C, δ15N, and sterols. To further characterize coral health, we quantified energy reserves by measuring biomass, total lipids, and lipid classes. Additional analysis for C. caespitosa included carbohydrates (an energy reserve) and chlorophyll a (an indicator of photosynthetic capacity). Isotopic evidence shows that ambient-sourced Mediterranean corals, of both species, decreased heterotrophy in response to six months of low pH. Despite maintaining energy reserves, lower net photosynthesis (C. caespitosa) and a trend of declining calcification (A. calycularis) suggest a long-term cost to low heterotrophy under ocean acidification conditions. Conversely, vent-sourced corals maintained moderate (C. caespitosa) or high (A. calycularis) heterotrophic capacity and increased photosynthesis rates (C. caespitosa) in response to six months at low pH, allowing them to sustain themselves physiologically. Provided there is sufficient zooplankton and/or organic matter to meet their heterotrophic needs, vent-sourced corals are more likely to persist this century and potentially be a source for new corals in the Mediterranean.

Contrasting effects of increasing dissolved iron on photosynthesis and O2 availability in the gastric cavity of two Mediterranean corals.

Iron (Fe) plays a fundamental role in coral symbiosis, supporting photosynthesis, respiration, and many important enzymatic reactions. However, the extent to which corals are limited by Fe and their metabolic responses to inorganic Fe enrichment remains to be understood. We used respirometry, variable chlorophyll fluorescence, and O2 microsensors to investigate the impact of increasing Fe(III) concentrations (20, 50, and 100 nM) on the photosynthetic capacity of two Mediterranean coral species, Cladocora caespitosa and Oculina patagonica. While the bioavailability of inorganic Fe can rapidly decrease, we nevertheless observed significant physiological effects at all Fe concentrations. In C. caespitosa, exposure to 50 nM Fe(III) increased rates of respiration and photosynthesis, while the relative electron transport rate (rETR(II)) decreased at higher Fe(III) exposure (100 nM). In contrast, O. patagonica reduced respiration, photosynthesis rates, and maximum PSII quantum yield (Fv/Fm) across all iron enrichments. Both corals exhibited increased hypoxia (<50µmol O2 L-1) within their gastric cavity at night when exposed to 50 and 100 nM Fe(III), leading to increased polyp contraction time and reduced O2 exchange with the surrounding water. Our results indicate that C. caespitosa, but not O.patagonica, might be limited in Fe for achieving maximal photosynthetic efficiency. Understanding the multifaceted role of iron in corals' health and their response to environmental change is crucial for effective coral conservation.

Response of two temperate scleractinian corals to projected ocean warming and marine heatwaves.

The Mediterranean Sea is a hotspot of global change, particularly exposed to ocean warming and the increasing occurrence of marine heatwaves (MHWs). However, experiments based on long-term temperature data from the field are scarce. Here, we investigate the response of the zooxanthellate coral Cladocora caespitosa and the azooxanthellate coral Astroides calycularis to future warming and MHWs based on 8 years of in situ data. Corals were maintained in the laboratory for five months under four temperature conditions: Warming (3.2°C above the in situ mean from 2012 to 2020), Heatwave (temperatures of 2018 with two heatwaves), Ambient (in situ mean) and Cool (deeper water temperatures). Under the Warming treatment, some C. caespitosa colonies severely bleached and A. calycularis colonies presented necrosis. Cladocora caespitosa symbiosis was impaired by temperature with a decrease in the density of endosymbiotic algae and an increase in per cent whiteness in all the treatments except for the coolest. Recovery for both species was observed through different mechanisms such as regrowth of polyps of A. calycularis and recovery of pigmentation for C. caespitosa. These results suggest that A. calycularis and C. caespitosa may be resilient to heat stress and can recover from physiological stresses caused by heatwaves in the laboratory.

Occurrence of phthalic acid esters (PAEs) and active pharmaceutical ingredients (APIs) in key species of anthozoans in Mediterranean Sea

The Mediterranean Sea's biodiversity is declining due to climate change and human activities, with plastics and emerging contaminants (ECs) posing significant threats. This study assessed phthalic acid esters (PAEs) and active pharmaceutical ingredients (APIs) occurrence in four anthozoan species (Cladocora caespitosa, Eunicella cavolini, Madracis pharensis, Parazoanthus axinellae) using solid phase microextraction (SPME) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). All specimens were contaminated with at least one contaminant, reaching maximum values of 57.3 ng/g for the ∑PAEs and 64.2 ng/g (wet weight) for ∑APIs, with dibutyl phthalate and Ketoprofen being the most abundant. P. axinellae was the most contaminated species, indicating higher susceptibility to bioaccumulation, while the other three species showed two-fold lower concentrations. Moreover, the potential adverse effects of these contaminants on anthozoans have been discussed. Investigating the impact of PAEs and APIs on these species is crucial, given their key role in the Mediterranean benthic communities.

Potentialities of the combined use of underwater fluorescence imagery and photogrammetry for the detection of fine-scale changes in marine bioconstructors

Marine communities are facing both natural disturbances and anthropogenic stressors. Bioconstructor species are endangered by multiple large-scale and local pressures and the early identification of impacts and damages is a primary goal for preserving coral reefs. Taking advantage of the recent development in underwater photogrammetry, the use of photogrammetry and fluorimetry was coupled to design, test and validate in laboratory a multi-sensor measuring system that could be potentially exploited in open water by SCUBA divers for assessing the health status of corals and detecting relevant biometric parameters with high accuracy and resolution. The approach was tested with fragments of the endemic coral Cladocora caespitosa, the sole zooxanthellate scleractinian reef-builder in the Mediterranean. The most significant results contributing to the scientific advancement of knowledge were: 1) the development of a cost-effective, flexible and easy-to-use approach based on emerging technologies; 2) the achievement of a sub-centimetric resolution for measuring relevant biometric parameters (polyp counting, colony surface areas and volumes); 3) set up of a reliable and repeatable strategy for multi-temporal analyses capable of quantifying changes in coral morphology with sub-centimeter accuracy; 4) detect changes in coral health status at a fine scale and under natural lighting through autofluorescence analysis. The novelty of the present research lies in the coupling of emerging techniques that could be applied to a wide range of 3D morphometrics, different habitats and species, thus paving the way to innovative opportunities in ecological research and more effective results than traditional in-situ measurements. Moreover, the possibility to easily modify the developed system to be installed on an underwater remotely operated vehicle further highlights the possible concrete impact of the research for ecological monitoring and protection purposes.

What’s the key for success? Translocation, growth and thermal stress mitigation in the Mediterranean coral Cladocora caespitosa (Linnaeus, 1767)

Marine heat waves (MHWs) are affecting corals populations, advocating their inclusion in restoration actions since conservation measures may be not sufficient. Cladocora caespitosa is a Mediterranean reef-building, long-living species, with low recruitment rate and high juvenile mortality, leading to the need for its inclusion in international and European legislations. The aim of this study, conducted in the southern Tyrrhenian Sea, was to test the translocation of several C. caespitosa colonies thriving on an artificial substrate intended for demolition, applying transplantation techniques. Thirty-four colonies were transplanted in May 2018, and monitored over 4 years, to check for their persistence and health status. The shaded position of the recipient site resulted adequate, considering that colony survival rates were as high as 82.4%, 70.6% and 55.9% in October 2018, January 2020 and October 2022, respectively. Colonies presented signs of suffering only after the high temperatures occurred during summer 2022, with a decreasing rate of -2.5 ± 0.4 corallite/month. To better interpret the documented survival rates, 40 fragments of C. caespitosa were reared in aquaria to test temperature and light effects on growth rates and resistance to thermal stress, simulating a MHW and exacerbating the dim-light natural conditions of the recipient site, exposing half of the fragments to complete darkness. Only bigger fragments produced new corallites, with a rate of 1.3 ± 0.3 corallites/month, like the natural growth rate obtained in the field before the thermal anomaly, highlighting the suitability of ex-situ rearing as a potential tool to supply restoration project. After 5-days at 28.5°C, all fragments survived, despite showing tissue retraction, shorter tentacles, lower responsiveness, and zooxanthellae density variation. Overall, our results highlighted a promising plasticity of C. caespitosa in the field, representing a good candidate for restoration purposes. In aquaria this adaptive potential has been tested on a single genotype and more tests are needed to assess the intraspecific variability of these responses. A first insight into the species-based siting selection was provided to ensure the success of a restoration action. Our results point out the importance of knowing life history traits and ecological optima to design proper management and restoration measures.

The endangered coral Cladocora caespitosa in the Menorca Biosphere Reserve: Distribution, demographic traits and threats

Information on the distribution, population traits and conservation status of the endangered coral Cladocora caespitosa is still missing for most of its distribution area. As prompted throughout conservation assessments and red lists, obtaining such information is a priority in the current context of generalized decline of benthic communities in the Mediterranean Sea. We assessed these topics in the main C. caespitosa populations (n = 18) thriving throughout UNESCO's Menorca Biosphere Reserve (MBR), which includes the largest marine Biosphere Reserve in the Mediterranean Sea. The MBR harbours an arrange of C. caespitosa populations of great interest, with a good representation of the contrasted environmental conditions that this long-lived coral is able to thrive in. Although average coral cover falls into the lower range compared to other Mediterranean populations, it is the ubiquity of the species along Menorca's coastline that differentiates this location from others described to date. Warming-related mortality can be considered the main threat to this species in the MBR, showing an average colony necrosis of ∼30%. Nevertheless, special attention should also be paid to other potential threats derived from human activity, such as pollution and coastal development. This study should be used as a baseline to implement conservation and management actions in the MBR, including a long-term monitoring programme.

High bycatch rate of the coral Cladocora caespitosa offsets the low discards ratio in Thermaikos Gulf gillnet fishery

While hanging nets may have fewer overall environmental impacts than towed gears, they still catch unwanted species and sizes, which are then discarded. Gillnets are one of the most common types of nets used in Mediterranean small-scale fisheries, with commercial catches and discards containing a diverse range of fish and invertebrate species. In this study, the catch profile of gillnets in the Thermaikos Gulf (NE Mediterranean) was analyzed with a focus on the discarding of species with unfavorable conservation status, such as the Mediterranean-endemic scleractinian coral Cladocora caespitosa, which is listed as endangered due to declining population sizes. Our survey was conducted over two seasons (May to October in 2020 and 2021) and included 69 fishing trials under realistic fishing conditions. In general, gillnets exhibited a relatively low discards ratio (17.2%; 7.1% when only fish were considered) and a low prevalence and capture intensity of endangered or threatened species; during the entire survey, only one chondrichthyan was captured (1 specimen of Raja radula), while only two out of 54 fish species were of vulnerable IUCN status. These advantages were offset in part by the high catchability of C. caespitosa colonies, which occurred in 61% of hauls and accounted for 53% of total invertebrate biomass and 30% of total discarded biomass. The likelihood of hauling living colonies of C. caespitosa was higher when fishing over known coral beds (81% vs. 43%), and the overall probability of hauling C. caespitosa in any state was 18% higher over coral beds, suggesting that gillnets frequently detach colonies from the seafloor, which are then dispersed over a larger area as fragments with probably low survival potential. Our findings highlight the importance of identifying C. caespitosa beds so that fishermen avoid setting their nets in these areas, provided that they are well-informed and educated about the ecological significance of this endemic, threatened, and ecologically important species.

Mass Mortality of Shallow-Water Temperate Corals in Marine Protected Areas of the North Aegean Sea (Eastern Mediterranean)

Coral mortality is a global phenomenon of increasing magnitude, correlated with climate change. Prolonged marine heatwaves have particularly affected the north Aegean Sea in summer 2021, threatening shallow-water stony corals, such as Balanophyllia europaea and Cladocora caespitosa. To assess their population status, ten coastal, rocky-bottom stations dispersed in Natura 2000 sites of Chalkidiki (north Aegean) were surveyed using non-destructive techniques in autumn 2021. At each station, corals’ abundance was estimated in situ, by counting the number of B. europaea polyps within randomly placed 50 × 50 cm quadrats, and the number of C. caespitosa colonies along three replicate belt transects 1 × 10 m. The status of corals was qualitatively assigned as healthy, bleached (partially or complete), or in necrosis (partial or complete). B. europaea was found in 80% of stations; in total, 58.17% of the coral specimens were affected by necrosis. C. caespitosa was found in 30% of stations; in total, 27.49% of the coral colonies were partially bleached and 11.32% in necrosis. Another nine sessile invertebrates (sponges, bivalves, and ascidians) were observed in necrosis. These results highlight the need to establish monitoring programs on vulnerable sessile invertebrate populations along the Aegean Sea to assess climate change impacts.

Geochemical proxies of sea surface temperature from MIS 5e marine fossils in the Taranto Gulf (Ionian Sea, Southern Italy)

Well preserved fossil specimens of Thetystrombus latus, Spondylus gaederopus, Venus verrucosa, Pinna nobilis and Cladocora caespitosa, all coming from a MIS 5e fossiliferous calcarenite outcropping along the Mar Piccolo of Taranto coastline, were analyzed for trace elements and ∂18O and ∂13C isotopic composition in the carbonates of skeletons; with the aim to estimate the Sea Surface Temperature (SST) using different published equations. The adopted methods gave close values of the mean SST, even if with wide standard deviation values: 21.6 °C and of 21.1 °C, derived respectively from the Mg/Ca ratio of P. nobilis and from the Sr/ Ca ratio of C. caespitosa; 19.6 °C derived from the of C. caespitosa growth rate; 21.0 °C derived from the ∂18O. The similarity of these mean results could indicate that a moderate warming with an average of 2.8 °C, in respect to today, is the most likely climatic scenario of the Mar Piccolo of Taranto during the MIS 5e.

Middle-late Pleistocene chronology of palaeoshorelines and uplift history in the low-rising to stable Apulian foreland: Overprinting and reoccupation

To refine knowledge about terrace phases and uplift history for a tectonically poor deformed region, we apply the synchronous correlation method to reconstruct the chronology of a poorly constrained sequence of raised palaeoshorelines on the Apulian foreland, southern Italy. This work uses new chronological constraints obtained by amino acid racemisation (AAR) and isoleucine/alloisoleucine epimerisation (IE) on Patella spp., Thetystrombus latus (Gmelin), Glycymeris sp., and ostracods and U-series dating on corals Hoplangia durotrix Gosse and Cladocora caespitosa Linneo. This procedure provides a quantitative estimate of the vertical movements and associated rates within a region of the Apulian foreland. The synchronous correlation method uses sea-level highstands and uplift rate(s) as inputs; in particular, for sea-level highstands, the inputs are the age of the highstands and the sea-level elevation of the highstands relative to the present-day sea level. The output is a set of currently expected elevations of each sea-level highstand (the present elevations of palaeoshorelines). We then used regression analysis to assess the robustness between our observed palaeoshorelines and expected elevations of sea-level highstands. Our results show that the best fitting scenario is obtained using the sea-level curves of (i) Waelbroeck et al. (2002) from present to 410 ky BP and (ii) Rohling et al. (2014) from 410 to 590 ky BP as inputs for our synchronous correlation method, with uplift rates ranging from 0.09 mm/y to 0.07 mm/y with a mean value of 0.08 mm/y from 590 ky BP onwards.We recognised palaeoshorelines in the field belonging to the following highstands: 120 ky BP (MIS 5.5, second peak), 127 ky BP (MIS 5.5, first peak), 212 ky BP (MIS 7.3), 330 ky BP (MIS 9.3), 410 (MIS 11), 525 ky BP (MIS 13.3), and 590 ky BP (MIS 15). Our results show field observations of the reoccupation effect of younger palaeoshorelines over older ones due to the relatively slow uplift rates measured in the investigated area as predicted by our synchronous correlation method. In particular, we show a well-mapped and described reoccupation of the MIS 5.5 palaeoshoreline over the MIS 7.3 palaeoshoreline, constrained by new absolute dating.In addition, the data from the Apulian foreland suggest an MIS 7.3 highstand close to the present sea level.

The neglected status of the vermetid reefs in the Mediterranean Sea: A systematic map

• The research on Mediterranean marine habitats is unequally driven by European directives and laws. • A neglected habitat definition is provided. • Bibliometric analyses are used to define the neglected status of habitats. • In the Mediterranean Sea, coralligenous formations are mostly studied. • On the contrary, vermetid reefs can be defined as a neglected habitat. Studied since late 1800, vermetid reefs are marine bioconstructions of well-acknowledged importance in the Mediterranean Sea. Despite their persistence being jeopardized in the whole basin, recent studies have referred to this bioconstruction as a neglected habitat. In this study, we assessed the neglected status of the Mediterranean vermetid reefs in the scientific literature producing a systematic map through a multi-method bibliometric protocol. Scopus and Web of Science databases were jointly used for data collection. Vermetid reefs publication rate (i.e., number of publications per year) was investigated compared to the other Mediterranean bioconstructions using ANOVA analysis and Zero-Inflated Poisson regression. Later, VOSviewer software was used to perform a bibliometric network analysis and for mapping visualization. The analysis aimed at investigating gaps, patterns, and trends of the vermetid reefs together with the other main Mediterranean bioconstructions (i.e., Astroides calycularis , Cladocora caespitosa and coralligenous formations, and sabellariid and Lithophyllum reefs). The ANOVA analysis of the number of publications from 1966 to 2020 found statistically significant differences between coralligenous and vermetid reefs publication rates in the 2006–2010, 2011–2015, and 2016–2020 timeframes and pointed out a clear before/after-2010 pattern in coralligenous publication rate, which was also confirmed by the Zero-Inflated Poisson regression model. The bibliometric network analysis of the bioconstructions literature revealed the same temporal pattern, with the vermetid reefs poorly investigated and weakly connected to newer research lines and conservation topics. Instead, coralligenous showed strong connections with biodiversity conservation and was indicated as a recent research hotspot. Overall, the results of this study confirm previous references of the vermetid reefs as a neglected habitat and, among others, show an increasing research interest in the coralligenous topic.

Genetic Structure of the Endangered Coral Cladocora caespitosa Matches the Main Bioregions of the Mediterranean Sea.

Population connectivity studies are a useful tool for species management and conservation planning, particular of highly threatened or endangered species. Here, we evaluated the genetic structure and connectivity pattern of the endangered coral Cladocora caespitosa across its entire distribution range in the Mediterranean Sea. Additionally, we examined the relative importance of sexual and asexual reproduction in the studied populations and their genetic diversity. A total of 541 individuals from 20 localities were sampled and analysed with 19 polymorphic microsatellite markers. Of the genotyped individuals, 482 (89%) had unique multilocus genotypes. Clonality percentages of the populations varied from 0% (in eight populations) to nearly 69% (in one population from Crete). A heterozygosity deficit and a high degree of inbreeding was the general trend in our data set. Population differentiation in C. caespitosa was characterised by significant pairwise F ST values with lower ones observed at an intraregional scale and higher ones, between populations from different biogeographic regions. Genetic structure analyses showed that the populations are divided according to the three main sub-basins of the Mediterranean Sea: the Western (Balearic, Ligurian and Tyrrhenian seas), the Central (Adriatic and Ionian seas) and the Eastern (Levantine and Aegean seas), coinciding with previously described gene flow barriers. However, the three easternmost populations were also clearly separated from one another, and a substructure was observed for the other studied areas. An isolation-by-distance pattern was found among, but not within, the three main population groups. This substructure is mediated mainly by dispersal along the coastline and some resistance to larval movement through the open sea. Despite the low dispersal ability and high self-recruitment rate of C. caespitosa, casual dispersive events between regions seem to be enough to maintain the species’ considerable genetic diversity. Understanding the population connectivity and structure of this endangered scleractinian coral allows for more informed conservation decision making.

Pre-assessment of zoobenthos diversity from the only hard coral Marine Reserve in the Turkish Seas (Çanakkale Strait, Turkey)

Marine Protected Areas (MPAs) and their management have become more significant than ever due to the growing impacts of pollution, overfishing and illegal hunting activities in marine environments. Corals, as habitat forming species that create biodiversity hotspots, provide structural support, shelter and a nursery ground for associated biota. The present paper deals with the pre-assessment of invertebrate assemblages living in hard coral (Cladocora caespitosa) reef in the marine protected area (Dardanos Cladocora Reefs) of the Çanakkale Strait. In the study (DarINVERTA7) conducted between 2017 and 2021, 62 benthic invertebrate species, belonging to eight taxonomic groups were reported for the first time from the region of which five species (Clathria (Clathria) compressa, Rynchozoon neapolitanum, Hornera frondiculata, Polycitor adriaticus and Aplidium nordmanni) were new for the Turkish coasts.

The cytotoxic activity of Sponges and Tunicates from Turkish Aegean Sea

The enormous bioactive components of different species from marine habitats make them attractive candidates for the discovery of new therapeutic active substances in several diseases such as cancer. Sea sponge and tunicate materials are the ideal sources of new chemotherapeutics for various cancers due to their rich metabolites. The fundamental purpose of the current study is to investigate the cytotoxic activity of methanolic crude extracts of sponges (Agelas oroides and Cladocora caespitosa) and tunicates (Ascidiella aspersa&nbsp;and&nbsp;Styela clava) collected from the Aegean Sea. The cytotoxic activity and the anti-cancer activity of the extracts was carried out by sodium 3´- [1- (diphenyl aminocarbonyl)-3,4-tetrazolium] -bis (4-methoxy 6-nitro) benzene sulfonic acid hydrate (XTT) on gastric adenocarcinoma cell line AGS, prostate cancer cell line PC-3, neuroblastoma cell line SH-SY5Y, and mouse fibroblast cell line L929. The extracts of sponge and tunicate were found to cause different cytotoxic effects on different cancer cells, largely in a concentration-dependent manner. It is found that the extracts exhibited high anti-cancer activities in neuroblastoma and prostate cancer cell lines at concentrations of 3 and 5 mg/ml. No significant cytotoxic activity was found in L929 cells. In addition, the microscopic examination of cells treated with the extracts shows that the extracts cause morphological changes with cellular rounding, which could be associated with apoptosis.

Two temperate corals are tolerant to low pH regardless of previous exposure to natural CO2 vents

AbstractOcean acidification is perceived to be a major threat for many calcifying organisms, including scleractinian corals. Here, we investigate (1) whether past exposure to low pH environments associated with CO2 vents could increase corals tolerance to low pH and (2) whether zooxanthellate corals are more tolerant to low pH than azooxanthellate corals. To test these hypotheses, two Mediterranean colonial corals Cladocora caespitosa (zooxanthellate) and Astroides calycularis (azooxanthellate) were collected from CO2 vents and reference sites and incubated in the laboratory under present day (pH on the total scale, pHT 8.07) and low pH conditions (pHT 7.70). Rates of net calcification, dark respiration, and photosynthesis were monitored during a 6‐month experiment. Monthly net calcification was assessed every 27–35 d using the buoyant weight technique, whereas light and dark net calcification was estimated using the alkalinity anomaly technique during 1‐h incubations. Neither species showed any change in net calcification rates, respiration, and photosynthesis regardless of their environmental history, pH treatment, and trophic strategy. Our results indicate that C. caespitosa and As. calycularis could tolerate future ocean acidification conditions for at least 6 months. These results will aid in predicting species' future responses to ocean acidification, and thus improve the management and conservation of Mediterranean corals.

Late Quaternary uplift and sea level fluctuations along the Tyrrhenian margin of Basilicata - northern Calabria (southern Italy): New constraints from raised paleoshorelines

New analyses of marine terraces in the Tyrrhenian Sea margin of Basilicata - northern Calabria (southern Italy) have been carried out. In the study area, c. 25 km in length, an impressive flight of marine terraces occurs, with the highest terraces reaching ~160 m a.s.l. Detailed geomorphological-stratigraphical analyses on remnants of paleoshorelines located within 60 m a.s.l. have shown that the rocky coast of the investigated coastal stretch has been affected by multiple relative sea-level fluctuations, during which reworking of older shorelines has occurred. Dating of the coral Cladocora caespitosa and speleothems, either predating or postdating single paleoshorelines, has allowed the construction of a chronological framework for the identified relative sea-level markers, and their correlation with MIS 7, MIS 6e and distinct peaks of MIS 5. A mean uplift rate of c. 0.25 mm/y since the Last Interglacial has been quantified, one order of magnitude larger than previous estimates. The uplift rate value has been used to infer the elevations of MIS 5a, 5c and 6e sea level peaks, which are higher than those reported in most sea level curves worldwide, although consistent with several findings from the western Mediterranean. Our results demonstrate that a mere sequential correlation may be misleading in the interpretation of flights of marine terraces and indicates that multiple age controls are crucial to unravelling the complex interaction between uplift and sea-level fluctuations in uplifted coastal areas. The reconstructed MIS 5a, 5c and 6e sea level paleo-elevations, besides contributing to the assessment of late Quaternary sea-level fluctuations in the Mediterranean Sea, may contribute to constrain coeval ice sheets volume variations.

Ecological patterns of polychaete assemblages associated with the Mediterranean stony coral Cladocora caespitosa (Linnaeus, 1767): a comparison of sites in two biogeographic zones (Adriatic and Aegean Sea)

The Mediterranean stony coral Cladocora caespitosa (Linnaeus, 1767) is a well-known habitat builder, and as such hosts a diversified faunal assemblage. Although polychaetes are one of the most abundant and diverse macrobenthic groups associated with C. caespitosa colonies, our knowledge of their ecological features in this association is still limited. The aim of this paper was to gather and compare the most comprehensive data available on polychaetes associated with C. caespitosa in the Adriatic and the Aegean Seas, and to test for differences between these geographic areas. To this end, differences were tested in terms of: (i) richness and structure of polychaete assemblages; (ii) feeding and functional traits of assemblages; (iii) the main factors influencing those aspects, (iv) the relationship between polychaete assemblages richness and Cladocora colony size, and estimate richness. Differences were observed between the Adriatic and the Aegean Seas, in terms of richness, species composition and relative proportion of the dominant feeding guild (filter feeders most abundant in the Aegean and carnivores in the Adriatic) and motility mode (sessile most abundant in the Aegean and motile in the Adriatic). Conversely, cosmopolitan and Atlanto-Mediterranean species dominated the assemblages in both geographic areas, and the same Species-Area Relation model proved to be effective for richness estimation in both geographic areas.

Co-occurrence of a reef-building coral and canopy-forming macroalgae in the Mediterranean Sea

Canopy-forming macroalgae are amongst the main competitors of corals by affecting coral recruitment, growth of recruits and adults, fecundity and in the worst-case scenario causing coral bleaching and necrosis. However, potentially reef-building coral Cladocora caespitosa (Linnaeus, 1767) and canopy-forming macroalgae of the order Fucales (Cystoseira sensu lato) are known to concur in a few places of the Mediterranean Sea. Here we look at the small-scale relationships between Cladocora abundance and Cystoseira s. l. densities at three different places where they coexist. Relationships have turned out to be both species and site-specific even though most relationships are neutral, pointing to a predominant concurrence of corals and macroalgae at the small scale. These findings shed new information on the relationship between corals and fleshy macroalgae in a temperate environment and serve as a starting point for future studies addressing the interactions between C. caespitosa and Cystoseira s. l.