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

Effect of temperature and food concentration on the relationship between growth and AARS activity in Paracartia grani nauplii 1Institute of Oceanography and Global Change 2Instituto Español de Oceanografía Inma Herrera1, Lidia Yebra2and Santiago Hernández-Léon1 Efecto de la temperatura y de la concentración de alimento en la relación entre el crecimiento somático y la actividad de la enzima aminoacil ARNt sintetasa en nauplios de Paracartia grani Paracartia grani (Sars, G.O. 1904) Typical of coastal area Conditioned: Physical factors (temperature) Biological factors (food) Acartiidae are common in coastal and estuarine habitats worldwide. An important component in the diet of a many of plankton species. OBJECTIVE The relationship between direct growth rates and specific AARSsitu activities to validate the AARS method as growth index for this species under different temperatures (12-28ºC) and food quantity (0-880 µg C·L-1). The effect of temperature and food quantity on the growth of Paracartia grani (Sars 1904). METHODOLOGY Oxyrrhis marina ICM Institute of Marine Sciences Paracartia grani 12h day: 12h night photoperiod Rhodomonas baltica f/2 medium 24 hours Eggs were collected and preserved in the fridge (4ºC) METHODOLOGY Experiments at different temperatures 12 º C 16 º C 19.8 º C 24 º C 26 º C 28 º C Eggs addition: (22.000-64.548) 16 hours Oxyrrhis marina 220-286 μgC·L-1 (~2 nauplii mL-1) METHODOLOGY Experiments under different food concentrations 0µg C·L -1 11 µg C·L-1 55 µg C·L-1 110 µg C·L-1 220 µg C·L-1 440 µg C·L-1 880 µg C·L-1 (~2 nauplii mL-1) METHODOLOGY 100 ml nauplii culture Fixed with Lugol’s acid (4%) Measured of length and abundance Multisizer Coulter Counter Nauplii growth experiments Converted in carbon (C) assuming a carbon/dry weight ratio of 0.40 (Postel et al. 2000). Length measurement and weight-specific growth calculations Dry weight (dw) / length Durbin and Durbin (1978) A.clausi W = 19.04 L 2.849, r= 0.99 W = dry weight (μg) L = prosome length(mm) Temperature quotient (Q10) R1and R2= Growth rates T1and T2= Temperatures Protein synthesis Aminoacids mRNA Ribosome Ribosome reading a RNA chain prior to the synthesis of a protein (Whitesides, 2001). Protein Fig 2. Paracartia grani nauplii. Effect of temperature on A) growth (d-1), B) spAARSs(nmPPi·mg prot-1·h-1), C) individual AARSs(nmPPi·ind-1·h-1). RESULTS & DISCUSSION Temperature (ºC) 10 14 18 22 26 30 Individual AARSs (nmPPi · ind-1 · h-1) 0.000 0.005 0.010 0.015 0.020 0.025 10 14 18 22 26 30 Growth (d-1) 0.0 0.2 0.4 0.6 0.8 1.0 10 14 18 22 26 30 spAARSs (nmPPi · mg prot-1 · h-1) 20 40 60 80 100 120 G = -0.188 + 0.038 · T r2 = 0.984, p < 0.001 spAARSs= -42.51 + 5.44 · T r2 = 0.942, p < 0.001 AARSs·ind-1 = -0.010 + 0.001 · T r2 = 0.852, p < 0.001 Q10 2.1 Q10 2.1 Q10 2.4 RESULTS & DISCUSSION Fig 5. Paracartia grani nauplii. Relationship between growth rates (d-1) and A) specific AARSs activities (nmPPi·mg prot-1·h-1), B) individual AARSs (nmPPi·ind-1·h-1) at different temperatures (ºC). spAARSs (nmPPi·mg prot-1·h-1) 20 40 60 80 100 120 -0.1 0.1 0.3 0.5 0.7 0.9 Individual AARSs (nmPPi·ind-1·h-1) 0.000 0.005 0.010 0.015 0.020 0.025 -0.1 0.1 0.3 0.5 0.7 0.9 Growth (d-1) A B G = 0.25 + 31.65 · AARSs·ind-1 r2 = 0.833, p < 0.001 G = 0.13 + 0.007 · spAARSs r2 = 0.945, p < 0.001 Yebra et al., 2005 Calanus helgolandicus R2=0.55 Yebra et al., 2006 Calanus finmarchicus R2= 0.55 RESULTS & DISCUSSION Days after hatching ln weight (ng C) 0 µ g C·L -1 012345678 2 3 4 5 6 11 µ g C·L -1 012345678 2 3 4 5 6 55 µ g C·L -1 012345678 2 3 4 5 6 110 µ g C·L -1 012345678 2 3 4 5 6 220 µ g C·L -1 012345678 2 3 4 5 6 440 µ g C·L -1 012345678 2 3 4 5 6 880 µ g C·L -1 012345678 2 3 4 5 6 -0.01 - 0.68 d-1 Fig 3. Paracartia grani nauplii. Carbon content (ng C) increases under different food concentrations. Food concentration (µg C·l-1) 0 200 400 600 800 1000 Individual AARSs (nmPPi · ind-1 · h-1) 0.000 0.002 0.004 0.006 0.008 0 200 400 600 800 1000 Growth (d-1) -0.1 0.1 0.3 0.5 0.7 0.9 0 200 400 600 800 1000 spAARSs (nmPPi · mg prot-1 · h-1) 20 30 40 50 60 70 80 RESULTS & DISCUSSION Fig 4. Paracartia grani nauplii. Effect of food concentration on A) growth (d-1), B) spAARSs(nmPPi·mg prot1·h-1), C) individual AARSs(nmPPi·ind-1·h-1); open circle: value not included in fit (see text). G = 0.65 · (1 – e(–0.013·C)) r2 = 0.986, p < 0.001 AARSs·ind-1 = 0.0032 + 0.0004 ln(C) r2= 0.907, p < 0.05 RESULTS & DISCUSSION Fig 6. Paracartia grani nauplii. Relationship between growth rates (d-1) and A) specific AARSs activities (nmPPi·mg prot-1·h-1), B) individual AARSs(nmPPi·ind-1·h-1) under different food concentrations (µg C·L-1); open circle: value not included in fit (see text). spAARSs (nmPPi · mg prot-1 · h-1) 20 30 40 50 60 70 -0.1 0.1 0.3 0.5 0.7 0.9 Individual AARSs (nmPPi · ind-1 · h-1) 0.000 0.002 0.004 0.006 -0.1 0.1 0.3 0.5 0.7 0.9 Growth (d-1) A BG = -0.59 + 204.46 · AARSs·ind-1 r2 = 0.951, p < 0.001 G = 1.49 - 0.025 · spAARSs r2 = 0.958, p < 0.0001 RESULTS & DISCUSSION Fig 7. Paracartia grani nauplii. A) Relationship between specific AARSsactivities (nmPPi·mg prot-1·h-1)and individual biomass (µg proteins · ind-1); B) Relationships between daily growth rates (d-1)andspecific AARSsactivities (nmPPi·mg prot-1·h-1) under different food concentrations. 20 30 40 50 60 70 80 90 spAARS s (nmPPi · mg prot -1 · h -1 ) -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 Daily growth rate starvation level intermediate level saturation level 0.00 0.05 0.10 0.15 0.20 0.25 0.30 µg proteins·ind -1 0 10 20 30 40 50 60 70 80 90 spAARSs (nmPPi·mg prot-1·h-1) spAARSs= 64.3 – 165.0 · ind biomass r2 = 0.490, p < 0.0001 CONCLUSIONS Growth and protein synthesis rates of Paracartia 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. The results presented here add to previous studies showing that the AARSsactivity is a useful tool for estimating somatic growth in copepods. ACKNOWLEDGMENTS Zooplankton Ecology Group at the Institute of Marine Sciences (ICM, Barcelona, Spain) Oithona project (CTM2007-60052) and Lucifer project (CTM2008-03538/MAR) Thank you for your attention! [email protected] Inma Herrera