Astaxanthin determination in marine biological samples : an overview

Máster en Oceanografía

Efecto de los misidáceos en la calidad de la puesta en el caballito de mar, Hippocampus hippocampus (Linnaeus, 1758)

[EN]The importance of a suitable feeding in reproduction and spawning quality of teleost fish has been recognized as one of the major ?bottlenecks? in new aquaculture species like seahorses. Mysidacea species has been described as one of the main food for temperate seahorse species (Hippocampus hippocampus and H. guttulatus) in the wild. On the other hand, Artemia has been employed usually as marine food for rearing fish, including seahorses. The aim of this work is to study the effect of two different live preys (Artemia vs Mysis) in spawning quality of H. hippocampus broodstock. The animals were fed two times per day, six times per week. Spawning episodes and larvae quality was recorded. Seahorse fed on mysis showed significantly better results (p<0.05) than Artemia treatment, regarding spawning events, number of offspring?s and size. This fact showed the high potential of mysis as live prey for seahorses or other ornamental species.

Effect of temperature and food concentration on the relationship between growth and AARS activity in Paracartia grani nauplii

[EN]The in situ activity of the enzymes aminoacyl-tRNA synthetases (AARS) and the growth rates of naupliar stages of the planktonic marine copepod Paracartia grani were measured in the laboratory under different temperature and food concentrations. We assessed the effect of these parameters on growth and protein synthesis rates of P. grani nauplii. Growth and protein synthesis rates of P. grani nauplii depended on temperature and food concentration. AARS activity is valid as index of somatic growth for P. grani nauplii when growth is not limited by food availability. However, the relationship between protein-specific AARS activity and nauplii growth varied according to food availability levels. The degradation of proteins during starvation and/or the ß-oxidation of fatty acids affected the relationship between specific AARS activity and growth rates. The results presented here add to previous studies showing that the AARS activity is a useful tool for estimating somatic growth of this and other key copepod species. Nevertheless, further research is required to elucidate the validity of AARS activity as a universal proxy for growth.

Effect of temperature and food concentration on the relationship between growth

[EN] The in situ activity of the enzymes aminoacyl-tRNA synthetases (AARS) and the growth rates of naupliar stages of the planktonic marine copepod Paracartia grani were measured in the laboratory under different temperature and food concentrations. We assessed the effect of these parameters on growth and protein synthesis rates of P. grani nauplii. Growth and protein synthesis rates of P. grani nauplii depended on temperature and food concentration. AARS activity is valid as an index of somatic growth for P. grani nauplii when growth is not limited by food availability. However, the relationship between protein-specific AARS activity and nauplii growth varied according to food availability levels. The degradation of proteins during starvation and/or the ß-oxidation of fatty acids affected the relationship between specific AARS activity and growth rates. The results presented here add to previous studies showing that the AARS activity is a useful tool for estimating somatic growth of this and other key copepod species. Nevertheless, further research is required to elucidate the validity of AARS activity as a universal proxy for growth.

Planktonic potential CO2 emission calculation: preliminary results by applying an adapted enzymatic methodology to marine ecosystems

[EN]Isocitrate Dehydrogenase (IDH) is a key enzyme in the Krebs cycle, being responsible for the production of one of the three CO2 molecules related to cellular respiration. In order to measure the potential CO2 production linked to the marine planktonic community we have adapted an enzymatic methodology. Preliminary results show that different proportions of autotrophs, heterotrophs and mixotrophs and their metabolic pathways, lead to different relationships between potential CO2 emission and potential O2 consumption during cellular respiration. Although more experiments need to be made, this methodology is leading to a better understanding of cellular respiration in marine samples and their impact on the food chain, vertical Carbon flux and the current sequestering capacity for anthropogenic CO2.

On the respiratory metabolism of marine plankton: its application in assessing carbon fluxes and the role of substrates in its biochemical control

Programa de doctorado en Oceanografía. La fecha de publicación es la fecha de lectura

Testing zooplankton secondary production against growth in the marine mysid, "Leptomysis lingvura" (G.O. Sars, 1866)

[EN]Zooplankton growth and secondary production are key input parameters in marine ecosystem modelling, but their direct measurement is difficult to make. Accordingly, zooplanktologists have developed several statistical-based secondary production models. Here, three of these secondary production models are tested in Leptomysis lingvura (Mysidacea, Crustacea). Mysid length was measured in two cultures grown on two different food concentrations. The relationship between length and dry-mass was determined in a pilot study and used to calculate dry-mass from the experimental length data. Growth rates ranged from 0.11 to 0.64 , while secondary production rates ranged from 1.77 to 12.23 mg dry-mass . None of the three selected models were good predictors of growth and secondary production in this species of mysid.

Can zooplankton secondary production models predict growth in the marine mysid Leptomysis lingvura (G.O. Sars, 1866)?

[EN]Zooplankton growth and secondary production are key input parameters in marine ecosystem models, but their direct measurement is difficult to make. Accordingly, zooplanktologists have developed several statistical-based secondary production models. Here, three of these secondary production models are tested in the marine mysid Leptomysis lingvura (Mysidacea, Crustacea). Mysid length was measured in two cultures twice a day, which were grown on two different food concentrations. Growth rates ranged from 0.11 to 0.64 day-1, while secondary production rates ranged from 1.77 to 12.23 mg dry- mass day-1. None of the three selected models were good predictors of growth and secondary production in this mysid species.