• Energy Research

13 pages, 8 figures, supplemental material https://dx.doi.org/10.1007/s00338-016-1440-1 This study investigates the energetic investment during spawning of two Mediterranean gorgonians characterized by different reproductive strategies: Corallium rubrum (internal brooder) and Paramuricea clavata (surface brooder). Sexual products (number of oocytes and spermatic sacs) were quantified, and biochemical characteristics (lipid content and free fatty acid content and composition) were determined to investigate the parental energetic investment and demand in reproduction. Results suggested that the majority of the energetic cost was due to reproductive activity (i.e., gametogenesis and spawning). The two species exhibited different life history strategies, with P. clavata investing more energy in reproduction than C. rubrum. However, P. clavata is reproductively more sensitive to inter-annual changes in environmental conditions N. Viladrich was funded by a FI AGAUR research grant (FI-2010-03824), S. Rossi by a Ramón y Cajal contract (RyC-2007-01327) and a Marie Curie International Outgoing Fellowship (Animal Forest Health, Grant Agreement Number 327845). This work was supported by the BENTOLARV project (CTM2009-10007). The authors want to thank the support of the Generalitat de Catalunya to MERS (2014 SGR-1356) Peer Reviewed

17 pages, 12 figures, 3 tables The annual gonad development of a shallow (20 m depth) population of the Mediterranean gorgonian Eunicella singularis was found to be closely synchronized with that of a deep (60 m depth) population, but differences were observed in the gonadal output, with the shallow population producing more and larger sexual products. Lipid content in the shallow population showed a marked seasonality, peaking during summer. In contrast, lipid content remained persistently lower in the deep population. Fatty acids as well as C/N composition were also seasonal in the shallow population and more constant in the deep one. The isotopic composition (δ15N and δ13C) of the shallow colonies was similar to values observed for passive suspension feeders with symbiotic algae, whereas the deep colonies exhibited values similar to those of aposymbiotic passive suspension feeders that primarily feed on microzooplankton and particulate organic matter. These results highlight the importance of considering the depth-related variability among populations in order to achieve a better understanding of the ecology of sessile benthic suspension feeders A Gori was funded by a I3P contract of the Consejo Superior de Investigaciones Cientificas (Ref. I3P-BPD2005), N Viladrich was funded by a FI AGAUR research grant, L Bramanti was funded by Marie Curie IEF (Corgard, Project no. 221072), and S Rossi was funded by a Ramo´n y Cajal Contract (RyC-2007-01327). This work was supported by the BENTOLARV project (CTM2009-10007) Peer reviewed

The survival, behavior and competence period of lecithotrophic larvae depends not only on the energy allocation transferred by maternal colonies but also on the amount of energy consumed to sustain embryonic, larval, and post-larval development. The objective of the present work is to understand the effect of energy consumption on the performance of lecithotrophic larvae. To this aim, we analyzed free fatty acid (FFA) content and composition of the larvae of three Mediterranean octocorals (Corallium rubrum, Eunicella singularis and Paramuricea clavata) as a proxy for energy consumption. Results showed that C. rubrum larvae consume more FFA than P. clavata, whereas the energy consumed by E. singularis larvae is high but highly variable. These results are in accordance with the larval behavior of these three species since C. rubrum larvae are characterized by their high swimming activity frequency, P. clavata larvae are almost inactive, and the swimming activity frequency of E. singularis larvae is high, although variable. The differences in FFA composition of the larvae suggest contrasting energetic strategies that could explain the differences in survival and recruitment rates. In fact, high dispersal and recruitment capacities for E. singularis larvae can be inferred from the FFA composition, whereas the high spatial and temporal variability of recruitment observed in C. rubrum may be related to the non-selective transfer of fatty acid (FA) from maternal colonies. Finally, the high recovery rates after mass mortality events observed in P. clavata could be favored by the presence of a specific FA (22:6(n-3)) related to adaptation mechanisms under environmental stresses during the first developmental stages.

We evaluated the effects of low pH on Corallium rubrum from aquaria experiments. Several colonies of C. rubrum were long-term maintained for 314 days in aquaria at two different pH levels (8.10 and 7.81, pHT). Calcification rate, spicule morphology, major biochemical constituents (protein, carbohydrates and lipids) and fatty acids composition were measured periodically. Exposure to lower pH conditions caused a significant decrease in the skeletal growth rate in comparison to the control treatment. Similarly, the spicule morphology clearly differed between both treatments at the end of the experiment, with aberrant shapes being observed only under the acidified conditions. On the other hand, while total organic matter was significantly higher under low pH conditions, no significant differences were detected between treatments regarding total carbohydrate, lipid, protein and fatty acid composition. However, the lower variability found among samples maintained in acidified conditions relative to controls, suggests a possible effect of pH decrease on the metabolism of the colonies. Our results show, for the first time, evidence of detrimental ocean acidification effects on this valuable and endangered coral species. Supplement to: Bramanti, Lorenzo; Movilla, Juancho; Guron, Maricel; Calvo, Eva; Gori, Andrea; Dominguez-Cariò, Carlos; Grinyó, Jordi; Lopez-Sanz, Angel; Martinez-Quintana, Angela; Pelejero, Carles; Ziveri, Patrizia; Rossi, Sergio (2013): Detrimental effects of ocean acidification on the economically important Mediterranean red coral (Corallium rubrum). Global Change Biology, 19(6), 1897-1908

AbstractThe mean predicted decrease of 0.3–0.4 pHunits in the global surface ocean by the end of the century has prompted urgent research to assess the potential effects of ocean acidification on the marine environment, with strong emphasis on calcifying organisms. Among them, the Mediterranean red coral (Corallium rubrum) is expected to be particularly susceptible to acidification effects, due to the elevated solubility of its Mg‐calcite skeleton. This, together with the large overexploitation of this species, depicts a bleak future for this organism over the next decades. In this study, we evaluated the effects of lowpHon the species from aquaria experiments. Several colonies ofC. rubrumwere long‐term maintained for 314 days in aquaria at two differentpHlevels (8.10 and 7.81,pHT). Calcification rate, spicule morphology, major biochemical constituents (protein, carbohydrates and lipids) and fatty acids composition were measured periodically. Exposure to lowerpHconditions caused a significant decrease in the skeletal growth rate in comparison with the control treatment. Similarly, the spicule morphology clearly differed between both treatments at the end of the experiment, with aberrant shapes being observed only under the acidified conditions. On the other hand, while total organic matter was significantly higher under lowpHconditions, no significant differences were detected between treatments regarding total carbohydrate, lipid, protein and fatty acid composition. However, the lower variability found among samples maintained in acidified conditions relative to controls, suggests a possible effect ofpHdecrease on the metabolism of the colonies. Our results show, for the first time, evidence of detrimental ocean acidification effects on this valuable and endangered coral species.

The survival, behavior and competence period of lecithotrophic larvae depends not only on the energy allocation transferred by maternal colonies but also on the amount of energy consumed to sustain embryonic, larval, and post-larval development. The objective of the present work is to understand the effect of energy consumption on the performance of lecithotrophic larvae. To this aim, we analyzed free fatty acid (FFA) content and composition of the larvae of three Mediterranean octocorals (Corallium rubrum, Eunicella singularis and Paramuricea clavata) as a proxy for energy consumption. Results showed that C. rubrum larvae consume more FFA than P. clavata, whereas the energy consumed by E. singularis larvae is high but highly variable. These results are in accordance with the larval behavior of these three species since C. rubrum larvae are characterized by their high swimming activity frequency, P. clavata larvae are almost inactive, and the swimming activity frequency of E. singularis larvae is high, although variable. The differences in FFA composition of the larvae suggest contrasting energetic strategies that could explain the differences in survival and recruitment rates. In fact, high dispersal and recruitment capacities for E. singularis larvae can be inferred from the FFA composition, whereas the high spatial and temporal variability of recruitment observed in C. rubrum may be related to the non-selective transfer of fatty acid (FA) from maternal colonies. Finally, the high recovery rates after mass mortality events observed in P. clavata could be favored by the presence of a specific FA (22:6(n-3)) related to adaptation mechanisms under environmental stresses during the first developmental stages. 

15 pages, 6 figures, 4 tables Population dynamics, morphology, density, lipid contents and prey capture rates were studied in a patchy population of the tree-like passive suspension feeder Eudendrium racemosum (Cnidaria: Hydrozoa) during seasonal cycles. Density and size of colonies oscillated due to intraspecific competition (following the self-thinning rule) and predation (nudibranchs) showing size distributions in which alternatively large-and small-sized colonies were more abundant. Increase in the trophic impact on the water column was correlated with colony size (30.7 mg C m -2 d -1 in late spring-early summer compared with 10.2 mg C m -2 d -1 in the rest of the year). Lipid accumulation in the hydrocauli followed the same trend, being higher during the reproductive period (140 μg lipids mg -1 organic matter [OM]) compared with the rest of the year (70 μg lipids mg -1 OM). The short time cyclic variations reproduce, in a short time scale, the variations studied in other benthic suspension feeders, suggesting E. racemosum as a model organism to better understand the importance of large colonies in long-lived species in benthic-pelagic coupling processes. The accordance with the self-thinning rule found for this animal species strengthens the animal forest concept (a 3-dimensional live structure composed mainly by heterotrophic organisms such as gorgonians, bryozoans, and sponges), confirming the validity of the utilization, by marine ecologists, of the conceptual tools developed for terrestrial forest sciences. It is suggested that the impact of mature populations on benthic-pelagic coupling and biogeochemical cycles, simulated for long-lived species, could be validated by studying fast-growing species, in order to understand the importance of the preservation of complex structures and long-lived eco-engineering organisms in benthic habitats. © Inter-Research 2012 Support for this work was provided by a FPI fellowship from the ‘Ministerio de Educación y Ciencia’ and a Ramón y Cajal Contract (RyC-2007-01327) to S.R., by a CICYT grant and by the MAST-III-ELOISE European Union METRO MED Project. L.B. was supported by a Marie Curie Intra-European Fellowship within the 7th European Community Framework Programme (Project No. 221072 Peer Reviewed