Browsing by Author "Rocha, Rui J.M."
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- 3D chemoecology and chemotaxonomy of corals using fatty acid biomarkers: Latitude, longitude and depthPublication . Figueiredo, Cátia; Baptista, Miguel; Rosa, Inês; Lopes, Ana Rita; Dionísio, Gisela; Rocha, Rui J.M.; Cruz, Igor C.S.; Kikuchi, Ruy K.P.; Simões, Nuno; Leal, Miguel Costa; Tojeira, Inês; Bandarra, Narcisa; Calado, Ricardo; Rosa, RuiWith the objective of uncovering differences in the fatty acid (FA) composition of hexa- and octocorals from different climatic zones (equatorial, subtropical and tropical) and distinct habitats (e.g. rock and coral reefs; intertidal to deep-sea environments), the FA composition of 36 hexa- and octocoral species (132 specimens) was analysed (including the first characterization of organisms from the order Zoantharia and deep-sea gorgonians). PCA was applied in a FA matrix of the ten major PUFAs to detect differences among coral groups. Fatty acid profile analysis confirmed that C24 polyunsaturated FAs are suitable chemotaxonomic biomarkers to separate hexa- and octocorals. The polyunsaturated FA 22:6n-3 was identified as a useful biomarker to distinguish between zoantharians and scleractinians. Also, we discuss the role of food availability (type of phytoplankton assemblage) in relation to autotrophic carbon significance and in the establishment of FA profiles of octocorals from the West and East coasts of the Atlantic Ocean. Furthermore, we show that the occurrence of high levels of primary productivity hinder the use of FA profiles to distinguish between zooxanthellate and azooxanthellate octocorals. Finally, we present and discuss the particular traits of the FA profile of deep-sea gorgonians while comparing it with that of shallow species.
- Bacterial communities from corals cultured ex situ remain stable under different light regimes — Relevance for in toto aquaculturePublication . Pimentel, Tânia; Rocha, Rui J.M.; Rosa, Rui; Soares, Amadeu M.V.M.; Gomes, Newton C.M.; Leal, Miguel C.; Calado, RicardoMicrobial communities associated with corals are an important source of bioactive metabolites with great potential for drug discovery. However, culturing these symbiotic microbes is extremely complex and often impossible. In toto coral aquaculture performed ex situ (the culture of the holobiont–cnidarian host and associated microorganisms) has been suggested as a potential solution to solve the constraints of supplying metabolite biomass to fuel the drug discovery pipeline. In the present study we investigated if coral fragmentation and different light intensities (photosynthetically active radiation (PAR) of 50, 80 and 120 μmol quanta m− 2 s− 1) significantly affect the diversity and structure of the microbial communities present in the leather coral Sarcophyton cf. glaucum assessed through polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). The diversity and structure of the bacterial communities present in mother colonies and fragments stocked under identical conditions remained stable two months post fragmentation, as well as between coral fragments stocked under different PAR intensities. The observed stability in the microbial community supports that in toto coral aquaculture may be a suitable option to produce metabolite biomass from symbiotic microorganisms. The possibility to employ a low PAR intensity to grow coral fragments without significantly affecting their microbial diversity and structure is likely to decrease aquaculture production costs and improve its economic viability.
- Effect of tidal environment on the trophic balance of mixotrophic hexacorals using biochemical profile and photochemical performance as indicatorsPublication . Rosa, Inês C.; Rocha, Rui J.M.; Cruz, Igor; Lopes, Ana Rita; Menezes, Natália; Bandarra, Narcisa; Kikuchi, Ruy; Serôdio, João; Soares, Amadeu M.V.M.; Rosa, RuiFluctuations of environmental factors in intertidal habitats can disrupt the trophic balance of mixotrophic cnidarians. We investigated the effect of tidal environments (subtidal, tidal pools and emerged areas) on fatty acid (FA) content of Zoanthus sociatus and Siderastrea stellata. Effect on photophysiology was also accessed as an autotrophy proxy. There was a general tendency of a lower percentage of zooplankton-associated FAs in colonies from emerged areas or tidal pools when compared with colonies from the subtidal environment. Moreover, tidal environment significantly affected the photophysiology of both species. Colonies from the subtidal generally showed lower values of α, ETRmax and Ek when compared with their conspecifics from tidal pools or emerged areas. However, the absence of consistent patterns in Fv/Fm and in dinoflagellate-associated FAs, suggest that these corals are well adapted to intertidal conditions. This suggests that intertidal pressures may disturb the trophic balance, mainly by affecting heterotrophy of these species.