Building the future by doing more together

Microbial biodiversity and functional role in benthic food webs of the Condor seamount (NE Atlantic)
CESAM Responsible researcher - Teresa Amaro
Programme - PTDC/MAR/105486/2008
Execution dates - 2010-01-01 - 2012-12-31 (36 Months)
Funding Entity - FCT
Funding for CESAM - 10800 €
Total Funding - 197880 €
Proponent Institution - Universidade dos Açores (UAçores)
Participating Institutions
Universidade de Aveiro
Instituto do Mar, Centro Interdisciplinar de Coimbra (IMAR Coimbra/IMAR)

Departamento de Zoologia

The main aim of this project is to study seamount microbial communities, their biodiversity and their functional role in recycling organic matter and rendering it available to the benthic food web. We will use a multidisciplinary approach (using molecular, biochemical, microscopic and isotopic techniques) from the scale of single organisms to scale of the whole seamount ecosystem. Seamounts are usually isolated and typically cone-shaped elevations of the deep sea. Recent investigations have shown that these ecosystems are hot-spots of marine life. For their morphology seamounts affect ocean currents and cause eddies, turbulent mixing and up-or down-welling, which in turn modifies local primary and secondary production and provision of allochthonous organic material to the seafloor. Increased autochthonous and allochthnous production greatly enhance diversity and standing stocks of megafauna and attract top predators, including fish of commercial value. Prokaryotic microorganisms are known to have a deep influence on the quantity and quality of food available for benthic consumers and consequently on its standing stock and biodiversity. The discoveries of high metabolic activities and specific functional characteristics in deep-sea prokaryotes has lead to the conclusion that they play a pivotal role in deep-sea food webs, C and nutrient cycling, and overall deep-sea ecosystem functioning. Recent studies have suggested that also protists and viruses play key roles in deep-sea biogeochemical processes, controlling deep-sea prokaryotic production and contributing to the degradation of highly refractory organic matter. In recent years a considerable amount of information has been acquired on seamounts' ecology, but the overall microbial biodiversity, functional role, and contribution to the seamount food webs is still completely unexplored. The present proposal aims at elucidating the role of microbes in determining the transfer of energy up to the food web and the high production of the Condor seamount (Azores, NE Atlantic). In particular, we will investigate: i) the biodiversity and composition of the microbial assemblages (virus, prokaryotes, protists) associated to the sinking particles and to the seamount sediments, ii) the standing stocks and activity of these microbial components and contribution to biogeochemical processes; iii) the role of these components within the benthic food webs. The Condor seamount is the target of the recently approved project (CONDOR: Observatory for long-term study and monitoring of Azorean seamount ecosystems - PT0040 Co-financed by the EEA Grants Financial Mechanism - Iceland, Liechtenstein and Norway) and the present project will benefit of ship time and instruments available within the frame of this project. The consolidated and complementary expertise of the project partners, spanning from microbial ecology to molecular biology, benthic trophodynamics and whole ecosystem ecology, will assure the accomplishment of the objectives identified in the present proposal. Sediments and particulate organic matter will be collected from different sectors of the Condor seamount (summit, flanks and base) and in surrounding areas. Abundance and diversity of the microbial communities will be determined using a combination of epifluorescence counts, molecular hybridization, fingerprinting and cloning techniques. Functional parameters will include estimates of microbial biomass, microbial metabolism and production (enzymatic activities, 3H and 14C radio-labelled substrates incorporation), sediments biochemical composition and bioavailability. In order to track the contribution of microbial food chain to higher trophic levels, meio, to megabenthic specimens, previously selected on the base of their abundance and significance, will be collected with boxcores, ROV and submersible available from the CONDOR project. Stable C and N isotopic analyses conducted on metazoan tissues will be used to assess their diets and compared it to those of plankton, detritus, and bottom sediments as its potential food sources. We expect that results of this project will provide information concerning nutrient recycling and benthic processes occurring on seamounts in particular on the importance of the microbial components in the detrital food web. These results integrated with biological and oceanographic data from the CONDOR project will give the unique opportunity to perform a complete seamount modelling, integrating for the first time also the microbiological component. Only a complete understanding of the seamount ecosystem will allow to predict its resilience in virtue of present and future global changes and the best conservation and management practices. In addition, isolation of unknown microbial strains will potentially contribute to the discovery of bioactive compounds (e.g. ω-3 Poly unsaturated fatty acids) with great biotechnological interest.

Members on this project

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