Coral aquaculture is an activity of growing interest due to the degradation of coral reefs worldwide and concomitant growing demand for corals by three industries: marine ornamental trade, pharmaceutical industry and reef restoration. Although captive breeding and propagation of corals is a well-known activity among aquarium hobbyists and public aquariums, the link between coral science and aquaculture is still poorly developed. Research on coral biology has increased in the past decades and resulted in abundant scientific information that is pivotal to further advance coral aquaculture. This review presents a holistic overview of coral aquaculture in relation to coral biology, with particular focus on ex situ aquaculture. Success factors for commercial coral aquaculture are outlined, which include qualitative aspects, such as shape, coloration and natural product content, and quantitative parameters such as growth and volumetric productivity. Manipulation of environmental factors to maximize coral quality and volumetric productivity is thoroughly discussed, and a comprehensive overview of current propagation techniques is provided. Knowledge gaps are pinpointed to indicate directions for future research.

Coral aquaculture: applying scientific knowledge to ex situ production

The association between cnidarians and photosynthetic dinoflagellates within the genus Symbiodinium is a prevalent relationship in tropical and subtropical marine environments. Although the diversity of Symbiodinium provides a possible axis for niche diversification, increased functional range and resilience to physical stressors such as elevated temperature, how such diversity relates to the physiological balance between autotrophy and heterotrophy of the host animal remains unknown. Here we experimentally show inter- and intraspecific variability of photosynthetic carbon fixation and subsequent translocation by Symbiodinium to the model cnidarian host Aiptasia pallida . By using a clonal anemone line harboring different species of Symbiodinium , we determined that symbiont identity influences trophic plasticity through its density, capacity to fix carbon, quantity of translocated carbon, and ultimately the host′s capacity to ingest and digest prey. Symbiont carbon translocation and host prey ingestion were positively correlated across symbiont combinations that consisted of different isoclonal lines of S. minutum , while a combination with type D4-5 Symbiodinium displayed lower carbon translocation, and prey capture and digestion more similar to Aiptasia lacking symbionts. The absence of a shift toward greater heterotrophy when carbon translocation is low suggests that the metabolic demand of feeding and digestion may overwhelm nutritional stores when photosynthesis is reduced, and amends the possible role of animal feeding in resistance to or recovery from the effects of climate change in more obligate symbioses such as reef building corals.

https://ria.ua.pt/bitstream/10773/17904/1/858.full.pdf

Symbiont type influences trophic plasticity of a model cnidarian–dinoflagellate symbiosis

The chemical diversity associated with marine natural products (MNP) is unanimously acknowledged as the “blue gold” in the urgent quest for new drugs. Consequently, a significant increase in the discovery of MNP published in the literature has been observed in the past decades, particularly from marine invertebrates. However, it remains unclear whether target metabolites originate from the marine invertebrates themselves or from their microbial symbionts. This issue underlines critical challenges associated with the lack of biomass required to supply the early stages of the drug discovery pipeline. The present review discusses potential solutions for such challenges, with particular emphasis on innovative approaches to culture invertebrate holobionts (microorganism-invertebrate assemblages) through in toto aquaculture, together with methods for the discovery and initial production of bioactive compounds from these microbial symbionts.

/pdf/marine-microorganism-invertebrate-assemblages-perspectives-3xohb7knta.pdf

Marine Microorganism-Invertebrate Assemblages: Perspectives to Solve the “Supply Problem” in the Initial Steps of Drug Discovery

Bleaching (dinoflagellate symbiont loss) is one of the greatest threats facing coral reefs. The functional cnidarian–dinoflagellate symbiosis, which forms coral reefs, is based on the bi-directional exchange of nutrients. During thermal stress this exchange breaks down; however, major gaps remain in our understanding of the roles of free metabolite pools in symbiosis and homeostasis. In this study we applied gas chromatography–mass spectrometry (GC-MS) to explore thermally induced changes in intracellular pools of amino and non-amino organic acids in each partner of the model sea anemone Aiptasia sp. and its dinoflagellate symbiont. Elevated temperatures (32°C for 6 days) resulted in symbiont photoinhibition and bleaching. Thermal stress induced distinct changes in the metabolite profiles of both partners, associated with alterations to central metabolism, oxidative state, cell structure, biosynthesis and signalling. Principally, we detected elevated pools of polyunsaturated fatty acids (PUFAs) in the symbiont, indicative of modifications to lipogenesis/lysis, membrane structure and nitrogen assimilation. In contrast, reductions of multiple PUFAs were detected in host pools, indicative of increased metabolism, peroxidation and/or reduced translocation of these groups. Accumulations of glycolysis intermediates were also observed in both partners, associated with photoinhibition and downstream reductions in carbohydrate metabolism. Correspondingly, we detected accumulations of amino acids and intermediate groups in both partners, with roles in gluconeogenesis and acclimation responses to oxidative stress. These data further our understanding of cellular responses to thermal stress in the symbiosis and generate hypotheses relating to the secondary roles of a number of compounds in homeostasis and heat-stress resistance.

Metabolite profiling of symbiont and host during thermal stress and bleaching in a model cnidarian-dinoflagellate symbiosis.

The study of trophic ecology of benthic marine invertebrates with bi-phasic life cycles is critical to understand the mechanisms shaping population dynamics Moreover, global climate change is impacting the marine environment at an unprecedented level, which promotes trophic mismatches that affect the phenology of these species and, ultimately, act as drivers of ecological and evolutionary change Assessing the trophic ecology of marine invertebrates is critical to understanding maternal investment, larval survival to metamorphosis, post-metamorphic performance, resource partitioning and trophic cascades Tools already available to assess the trophic ecology of marine invertebrates, including visual observation, gut content analysis, food concentration, trophic markers, stable isotopes and molecular genetics, are reviewed and their main advantages and disadvantages for qualitative and quantitative approaches are discussed The challenges to perform the partitioning of ingestion, digestion and assimilation are discussed together with different approaches to address each of these processes for short- and long-term fingerprinting Future directions for research on the trophic ecology of benthic marine invertebrates with bi-phasic life cycles are discussed with emphasis on five guidelines that will allow for systematic study and comparative meta-analysis to address important unresolved questions

Trophic Ecology of Benthic Marine Invertebrates with Bi-Phasic Life Cycles: What Are We Still Missing?

Sea anemones of the genus Aiptasia are used as biological models for research and as a prey for the culture of the highly priced ornamental nudibranch Aeolidiella stephanieae. Symbiotic Aiptasia display a remarkable trophic plasticity, being able to fulfil their energetic demands heterotrophically and autotrophically. Consequently, they display a highly variable fatty acid (FA) profile. The objective of the present study was to analyse how light regime (12 h light : 12 h dark versus 24 h darkness), water temperature (22 versus 26 °C) and diet (Artemia nauplii versus enriched Artemia metanauplii) affect the FA composition of A. pallida. The FA profile of wild specimens was also analysed. The dominant FAs of cultured A. pallida were 16:0, 18:1n-9 and 22:6n-3. Higher FA levels were recorded when anemones were exposed to light, with this factor explaining the largest amount of variation in the composition of FA profiles. Cultured A. pallida that best mimicked wild anemones were obtained when using a regular light regime, Artemia metanauplii and 22 °C water temperature. Higher FA levels were obtained at a higher temperature and by providing nauplii to cultured anemones. The present study also indicated that A. pallida has the potential to recycle nutrients in marine aquacultures.

Effect of light, temperature and diet on the fatty acid profile of the tropical sea anemone Aiptasia pallida

Internal dosimetry intercomparisons are essential for the verification of applied models and the consistency of results'. To that aim, the First Regional Intercomparison was organised in 2005, and that results led to the Second Regional Intercomparison Exercise in 2013, which was organised in the frame of the RLA 9/066 and coordinated by Autoridad Regulatoria Nuclear of Argentina. Four simulated cases covering intakes of (131)I, (137)Cs and Tritium were proposed. Ninteen centres from thirteen different countries participated in this exercise. This paper analyses the participants' results in this second exercise in order to test their skills and acquired knowledge, particularly in the application of the IDEAS Guidelines. It is important to highlight the increased number of countries that participated in this exercise compared with the first one and, furthermore, the improvement in the overall performance. The impact of the International Atomic Energy Agency (IAEA) Projects since 2003 has led to a significant enhancement of internal dosimetry capabilities that strengthen the radiation protection of workers.

T.L. da Silva

Papers

Effect of light, temperature and diet on the fatty acid profile of the tropical sea anemone Aiptasia pallida

Second latin american intercomparison on internal dose assessment.