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

Alejandro Jesús Marrero Benítez Curso 2014/2015 May Gómez Cabrera Trabajo Fin de Título para la obtención del título de graduado en Ciencias del Mar Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 1 Trabajo de Fin de Título Grado en Ciencias del Mar Facultad de Ciencias del Mar Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) Trabajo presentado por Alejandro Jesús Marrero Benítez para la obtención del título de graduado en Ciencias del Mar en la Universidad de Las Palmas de Gran Canaria y dirigida por la Doctora Doña May Gómez Cabrera, grupo de investigación Ecofisiología de los Organismos Marinos (EOMAR). Universidad de Las Palmas de Gran Canaria En Las Palmas a 1 de junio de 2015 El alumno Fdo.: Alejandro Jesús Marrero Benítez La Directora Fdo.: May Gómez Cabrera Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 2 Index Abstract 3 Introduction 4 Material and methods 6 Results 10 Discussion 12 Conclusions Acknowledgements 17 17 References 18 Personal assessment 22 Figures index 1: Typical mysid side view 4 2: Location of the sampling area 6 3: Mysids aquaria 7 4: Leptomysis lingvura length and dry-mass relationship 4: Leptomysisl lingvura length growth 10 11 7: Daily growth rate 12 8: Daily secondary production rate 13 9:Predicted daily growth VS measured daily growth 14 Tables index 1: Greatest length and dry-mass in Leptomysis lingvura cultures 11 2: Growth and secondary production comparison between organisms 14 3: Daily growth rate obtained with the three models 4: Regression equations of the model-predicted secondary production rates 14 16 Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 3 Abstract 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 (90 and 240 Artemia nauplii per mysid, twice a day). 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 drymass . None of the three selected models were good predictors of growth and secondary production in this species of mysid. Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 4 Introduction Mysids are peracarida, crustaceans that inhabit many varied aquatic habitats (Tattersall and Tattersall, 1951; Mauchline and Murano, 1977). They are omnivorous and eat small planktonic organisms as well as organic detritus (Tattersall and Tattersall, 1951; Mauchline, 1980; Murano, 1999). Morphologically, they are characterized by having a thorax covered by a shell (not attached to the last four thoracic segments, unlike euphausiids), having a pouch on the ventral side of the body, and by having the first three thoracic appendages modified like maxilipeds;(the others thoracic appendages are left unmodified and similar to each other (Gómez, 2000)). In mysids identification, the most important morphological features are the telson, carapace, rostrum, eyes, antennal scale, pereopods and uropods (Fig.1). The taxonomy is difficult because the difference between two species of the same genre may be due to small morphological differences (Herrera, 2013). Mysids are abundant in different habitats such as the oceanic water column, seagrass meadows, the seafloor, caves, etc. (Herrera, 2009). Studies on the relationship between mysids and fish suggest that mysids are one of the most valuable fish-foods, especially in coastal regions (Murano, 1999). Fig. 1. Typical mysid in side view (Murano, 1999). Also, mysids are valuable food-chain components for other predators, especially those living in coastal and in seagrass areas. Mysids are found, in high abundance in Cymodocea nodosa seagrass meadows around the Canary Islands, as seen in the work Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 5 of Herrera (2013). They are the most abundant animal in this ecosystem, comprising at least 65% of all organisms that inhabit in this ecosystem (Herrera et al., 2014). In spring, seagrass meadows have a high shoot density and plant biomass (Tuya et al., 2006) that serves as a rich habitat and nursery for many organisms, including mysids. Accordingly, the combination of Cymodocea nodosa seagrass meadows and mysids likely play an important role in maintaining coastal productivity (Herrera, 2013). For this reason, it is essential to understand the growth (secondary production) of these crustaceans to quantitatively predict their impact on the productivity of coastal ecosystems. Secondary production reflects the net balance between metabolic gains and the integral of all metabolic losses (Gómez et al., 2012). Measurements of secondary production in the laboratory on one species are not the same as secondary production of a mixed zooplankton community in the ocean. Nevertheless, laboratory experimentation is a vital starting point, modelling is another one (Gómez et al., 2012). The first investigators to use modelling to predict secondary production in zooplankton were Huntley and López (1992). They used only temperature as their key variable. Later, other models were developed. Hirst and Sheader (1997) constructed their model from samples from the Arabian Sea. Huntley and Boyd (1984), based their model on temperature and body mass. The Hirst and Sheader (1997) model gave higher growth rates, but Peterson et al. (2002) had concluded that it was the best predictor of secondary production, even better than the Hirst and Lampitt (1998) model. Later, Miyashita et al. (2009), researching copepods in subtropical coastal seawater, confirmed that the Huntley and López (1992) model overestimates secondary production compared with the Hirst and Lampitt (1998) model. However, it has been shown that the Huntley and López model seems effective when food is not-limiting. For example, in areas such as estuaries and upwelling areas it seems to work (Peterson et al., 2002). Afterwards, Gómez et al. (2012) compared five models, including Huntley and López (1992), Hirst and Lampitt (1998), Hirst and Sheader (1997), Stockwell and Johannsson (1997) and Shuter and Ing (1997) models, with Daphnia magna laboratory data and; conclude that the best secondary production model for this organism was the Stockwell and Johannsson (1997) model. They noted that the Huntley and López (1992) model overestimates secondary production, as confirmed by previous studies and suggests Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 6 future avenues of research in which new models, would predict secondary production in other zooplankton species such as euphausiids or mysids. In this experiment, with the aim of understanding secondary production in natural mysids populations, growth and secondary production of the mysids Leptomysis lingvura (Wittman, 1981) were measured in cultures grown on different concentration of food. Leptomysis lingvura is one of the three mysid species found along the coast of Gran Canaria (Canary Islands, Spain). It is characterized for having a short carapace with a triangular face and a small, wide telson (Herrera, 2013).This species was chosen because of its important role in the Gran Canaria coastal ecosystem and because it grows well in the laboratory. In fact, it can complete its life cycle in captivity (Herrera, 2009; Herrera et al., 2011). This capacity to grow well in captivity greatly improves the facility to study growth and secondary production in the laboratory. Accordingly we grew this mysid in aquaria on different food concentrations and compared its growth with that predicted by the current models of secondary production in marine zooplankton. Material and methods Samples were taken at Risco Verde, on the east coast of Gran Canaria, Canary Islands (Fig. 2), on March 7th 2015, at depths between 15 and 20 meters using SCUBA equipment and a hand net. Fig. 2. Location of the sampling area. Distances obtained from IDE Canarias, visor Grafcan. Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 7 During the 10 days of acclimatization, mysids were placed on two plastic tanks of 40 L and were fed twice daily with 100 or 150 Artemia nauplii per mysid (the concentration of Artemia nauplii depended on the number of eggs that hatched). The seawater temperature, pH, and concentrations were monitored from the acclimatization period until the end of the experiment. The photoperiod was 14h:10h light and dark throughout the experiment. After this acclimatization, mysids were identified by species using a binocular microscope and following the works of Tattersall and Tattersall (1951), Wittman (1981), Murano (1999) and Herrera (2013). Then, Leptomysis lingvura were placed in 2 aquaria of 35 L, for adult breeders (Fig. 3) and 4 aquaria of 16 L for growing the juveniles. The water recirculation system of these aquaria was based on the system described in Lussier et al. (1988), with a 2 mm mesh siphon that transfers the juveniles to a 0.5 mm mesh collector, allowing adults and juveniles to be separated. Water flowed from aquaria to a biofilter, a tank where nitrifying bacteria oxidized to and then to . After that, the water passed through a skimmer to remove proteins from the organic material produced during nitrification. Finally, water was pumped back to the aquaria. During this experiment, the seawater temperature was maintained at 18.68±0.22ºC, the pH was maintained at 7.99±0.04, and the and , at concentrations below 0.05±0.01, 4±1.67 and 0.01±0.02 respectively. Fig. 3. Mysids aquaria. Mysids were counted daily and fed with various concentrations of 48 h (2 day-old) Artemia nauplii. Some of them were given twice daily 90 Artemia nauplii per mysid (first experiment), and the others were given twice daily 240 Artemia nauplii per mysid Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 8 (second experiment). The Artemia were enriched with Easy-DHA (INVE, Belgium).Then mysid growth was monitored. To measure the standard length, the distance from the rostrum between the eye stalks to the end of the last abdominal segment (Herrera et al., 2011) a binocular microscope with a Canon EOS 1000D 10-megapixel camera was used. The image was then measured with ImageJ 1.40g (National Institutes of Health, USA). Once all measurements were obtained, averages and standard deviations required to do the growth curves were calculated. From the initial measurement, the length increased per time in both cultures. The culture of 90 Artemia nauplii per mysid was followed for 35 days, but in the culture grown on 240 Artemia nauplii per mysid, the mysids died after 22 days. That tragedy limited the length of the second experiment to 22 days. Still, it was sufficiently long to achieve the experimental objectives. To obtain the relationship between length and dry-mass, some mysids (randomly selected for different size classes) were dried at 60ºC in a drying oven for 24 h. Then they were weighted on a Cobos balance with an ultramicroscale (+0.1 mg), according to Lovegrove (1966).The dry-mass data were plotted against the length (Fig. 4). The regression line was calculated to obtain the relationship between length and dry-mass. This was used to obtain the dry mass per time for both cultures. Lastly, growth rates were calculated from an exponential function fitted to the data (as shown in Gómez et al., 2012): (1) Where is the dry-mass at time t, is the dry-mass at time zero, t is the time (days), and g is the daily (24 hours) growth rate (Escribano and McLaren, 1992). The global rate of growth ( ) was calculated as the slope of the regression line in a plot of the log growth vs. time (Kimmerer and McKinnon, 1987). Using this equation, daily secondary production for both cultures, as dry-mass increase per mysid, per day, was calculated. All statistics were run using the R statistical package (Pinheiro et al., 2009; R Development Core Team, 2010), and the Shapiro-Wilk test for estimating whether the data was normal or not. The Student´s t-test and Wilcoxon signed rank test were used to evaluate if there was significant difference between regression lines. Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 15 The relation between the secondary production measurements and the calculated secondary production (growth rate) with the models can be seen on the regression equations of Table 3. It can be noted that none of the slopes lie parallel to the 1:1 line (Fig. 8). The reason for testing these secondary production models was to know if they were applicable to planktonic marine crustaceans such as mysids. The importance of mysids in many ecosystems, such as seagrass meadows, generated the original interest in using them for this experiment. Knowing their growth and production was helpful for understanding these ecosystems (Herrera, 2013). Fig. 8. Predicted daily growth versus measured daily growth in Leptomysis lingvura with two different food concentrations. (A) Models for mysids fed with 90 Artemia/mysid. (B) Models for mysids fed with 240 Artemia/mysid. The line in both graphics represents a 1:1 correspondence. In this study, none of the models predicted mysid growth or secondary production as compared to the measured laboratory growth rate (Fig. 8). The Huntley and López (1992) model overestimated secondary production, as described in numerous papers (Miyashita et al. 2009, Gómez et al. 2012). The reason for this is, basically, that it does not consider first principles; it doesn’t even consider biomass; it is simply a statistical relationship between growth and temperature. The Hirst and Sheader (1997) and Hirst and Lampitt (1998) models were closer to the measured growth and secondary production, but they still did not predict Leptomysis lingvura growth rate. Both underestimated secondary production in the mysids. None of these three models considered the biological machinery that controls growth in a cell nor did they consider environmental variables, such as salinity, oxygen concentration, pH, chlorophyll-a and other parameters that may be relevant when making secondary production models. They only considered temperature and biomass. Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 16 As a consequence, outside the data set from which they were originally derived, they are not applicable. Food concentration (Artemia/mysid) Huntley and López (1992) Hirst and Sheader (1997) Hirst and Lampitt (1998) 90 240 Table 4. Regression equations of the model-predicted rates of secondary production. Note that none slope is close to the 1:1 line. There are other models that have not been used in this study. The Hirst and Bunker (2003) model seems to describe Nature, as some authors have noted (Mackas et al., 2012). However, it includes chlorophyll as a variable, rendering it useless for carnivores as Ignatow et al., (1996) have shown for shrimps. The Stockwell and Johannsson (1997) and Shuter and Ing (1997) models also are useful for some situations (Miyashita et al., 2009, Gómez et al., 2012). Nonetheless, they are for freshwater zooplankton, specially, for cladocerans, and copepods. The results of this study argue that, in future secondary production models, either first principles of growth or more environmental variables should be considered. More variables that resonate with different ecological conditions and organisms should be evaluated to learn how they affect growth and secondary production. Models are needed that respond realistically to the many situations that can occur in Nature. Such models would have a chance to predict close approximations of growth in Nature. In all cases, since a laboratory culture is Nature simplified, if a model cannot predict growth there, then it will never be able to simulate growth in the infinitely more complicated natural ocean. Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 17 Conclusions 1.- This study showed that the growth of the marine mysid, Leptomysis lingvura is influenced by its food concentration. There were significant differences between daily growth on 90 Artemia nauplii per mysid and 240 Artemia nauplii per mysid. The wellfed mysids grew 13% larger than the poorly-fed mysids. 2.- Here, for the first time, for this mysid species, we find the length-dry mass relationship. It was: , . 3.- None of the three secondary production models were able to accurately predict measured growth and secondary production of Leptomysis lingvura. The Huntley and López (1992) model overestimated secondary production, while the Hirst and Sheader (1997) and Hirst and Lampitt (1998) underestimated it. 4.- The growth of Leptomysis lingvura cannot be modelled from temperature and biomass alone. Acknowledgements First, I would like to thank May Gómez and Ted Packard for giving me the opportunity to work with them, to expand my knowledge in this field, and for putting up with me all these months. Thanks also to Ico Martínez, for her enormous patience and help in the moments when I most needed her. Many thanks to MayteTamés and Gádor Muntaner for collecting the mysids. Many thanks, too, to Prof. Angelo Santana, for his instruction with the statistics. And finally, to all my colleagues and family, with special mention to Iguanira Lopez and María Casanova for her collaboration during this study. This study was supported by Project BIOMBA CTM2012-32729/MAR and by a grant from the Ministry of Education, Culture and Sports of the Government of Spain. Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 18 References Calbet, A., Trepat, I., and Arin, L. 2000. Naupliar growth versus egg production in calanoid copepod Centropages tipicus. Journal of Plankton Research. 22, 1393-1402. Chu, T., Sheng, Q., Wang, S., and Wu, J. 2014. Variability of Polychaete Secondary Production in Intertidal Creek Networks along a Stream-Order Gradient. PLOS ONE. 9, 1-9. Escribano, R., and McLaren, I.A. 1992. Influence of food and temperature on lengths and weights of two marine copepods. Journal of Experimental Marine Biology and Ecology. 159, 77-88. Gómez, M. 2000. Manual de prácticas de zoología marina. Chapter Crustáceos. Universidad de Las Palmas de Gran Canaria. pp 92-96. Gómez, M., Martínez, I., Mayo, I., Morales, J.M., Santana, A., and Packard, T.T. 2012. Testing zooplankton secondary production models against Daphnia magna growth.ICES Journal of Marine Science.69, 421-428. Herrera, A. 2009.Desarrollo de las técnicas de cultivo y estudio del metabolismo respiratorio de misidáceos. Master´sthesis. Universidad de Las Palmas de Gran Canaria. Herrera, A. 2013. Identification, Abundance and Rearing of Mysids from Gran Canaria: Application to Laboratory and Oceanographic Respiratory Metabolism Studies. Ph. D. thesis. Universidad de Las Palmas de Gran Canaria. Herrera, A., Gómez, M., Molina, L., Otero, F., and Packard, T.T. 2011. Rearing techniques and nutritional quality of two mysids from Gran Canaria (Spain).Aquaculture Research.42, 677-683. Herrera, A., Landeira, J.M., Tuya, F., Packard, T., Espino, F., and Gómez, M. 2014. Seasonal variability of suprabenthic crustaceans associated with Cymodocea nodosa seagrass meadows off Gran Canaria (eastern Atlantic). Continental Shelf Research. 88, 1-10. Hirst, A.G., and Bunker, A.J. 2003. Growth of marine planktonic copepods: Global rates and patterns in relation to chlorophyll a, temperature, and body weight. Limnology and Oceanography. 48, 1988-2010. Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 19 Hirst, A.G., and Lampitt, R.S. 1998. Towards a global model of in situ weight-specific growth in marine planktonic copepods. Marine Biology. 132, 247-257. Hirst, A.G., and Sheader, M. 1997. Are in situ weight-specific growth rates body-size independent in marine planktonic copepods? A re-analysis of the global syntheses and a new empirical model. Marine Ecology Progress Series. 154, 155-165. Huntley, M., and Boyd, C. 1984.Food-limited growth in marine zooplankton. The American Naturalist. 124, 455-478. Huntley, M.E. and López, M.D.G. 1992. Temperature-dependent production of marine copepods: a global synthesis. The American Naturalist. 140, 201-242. Ignatow, M., Mbahinzireki, G., and Lehman, J.T. 1996. Secondary production and energetics of the shrimp Caridina nilotica in Lake Victoria, East Africa: model development and application. Hydrobiologia. 332, 175-181. Kimmerer, W.J. 1987. The theory of secondary production calculations for continuously reproducing populations. Limnology and Oceanography. 32, 1-13. Kimmerer, W.J., Hirst, A.G., Hopcroft, R.R., and McKinnon, A.D. 2007. Estimating juvenile copepod growth rates: corrections, inter-comparisons and recommendations. Marine Ecology Progress Series. 336, 187-202. Kimmerer, W.J., and McKinnon, A.D. 1987. Growth, mortality and secondary production of the copepod Acartia tranteri in Westernport Bay, Australia. Limnology and Oceanography. 32, 14-28. Lin, K.Y., Sastri, A.R., and Hsieh, C.H. 2013. 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Sars, 1866) 20 Mackas, D.L., Greve, W., Edwards, M., Chiba, S., Tadokoro, K., Eloire, D., Mazzocchi, M.G., Batteh, S., Richardson, A.J., Johnson, C., Head, E., Conversi, A., and Peluso, T. 2012. Changing zooplankton seasonality in a changing ocean: Comparing time series of zooplankton phenology. Global Comparisons of Zooplankton Time Series. 97-100, 31-62. Mauchline, J. 1980. The biology of Mysids and Euphausiids.Advances in Marine Biology. 18, 1-681. Mauchline, J. and Murano, M. 1977. World list of the Mysidacea, Crustacea.Journal of the Tokio University of fisheries. 4, 39-88. Miyashita, L.K., De Melo, M., and Lopes, R.M. 2009.Estuarine and oceanic influences on copepod abundance and production of a subtropical coastal area.Journal of Plankton Research. 31, 815-826. Murano, M. 1999. South Atlantic Zooplankton.Volume 2, chapter Mysidacea, pp 10991140.Backhuy Publishers, Leiden, Holland. Peterson, W.T., Gómez-Gutierrez, J., and Morgan, C.A. 2002.Cross-shelf variation in calanoid copepods production during summer 1996 off the Oregon coast, USA.Marine Biology. 141, 353-365. Pinheiro, J.C., Bates, D.M., DebRoy, S., Sarkar, D., and the R Core team. 2009. Linear and Nonlinear Mixed Effect Models. R Package Version 3.1-96. R Development Core Team. 2010. R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria.409 pp. ISBN 3-900051-07-0. Shuter, B.J. and Ing, K.K. 1997.Factors affecting the production of zooplankton in lakes. Canadian Journal of Fisheries and Aquatic Sciencies. 54, 359-377. Stockwell, J.D. and Johannsson, O.E. 1997. Temperature-dependent allometric models to estimate zooplankton production in temperate freshwater lakes. Canadian Journal of Fisheries and Aquatic Sciences. 54, 2350-2360. Tattersall, W.M., and Tattersall, O.S. 1951. The British Mysidacea. Ray Society, London. Tuya, F., Martín, J., and Luque, A. 2006. Seasonal cycle of Cymodocea nodosa seagrass meadow and of the associated ichthyofauna at Playa Dorada (Lanzarote, Canary Islands, eastern Atlantic). Ciencias marinas. 27, 223-234. Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 21 Wittmann, K.J. 1981. Comparative biology and morphology of marsupial development in Leptomysis and other species Mediterranean Mysidacea (Crustacea).Journal of Experimental Marine Biology and Ecology.52, 243-270. Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 22 VALORACIÓN PERSONAL (PERSONAL ASSESSMENT) I.I Actividades desarrolladas A lo largo del Trabajo de Fin de Título (TFT), se han desarrollado una serie de actividades que pueden resumirse según lo descrito en la temporalización de TFT realizada. Según lo señalado en la misma, estas actividades se pueden determinar de la siguiente manera: la búsqueda bibliográfica de información sobre el tema a tratar en el experimento, el mantenimiento de los organismos de cultivo durante la fase experimental del proyecto, la realización de medidas y modelos matemáticos de acuerdo con el objetivo principal del proyecto y, finalmente, la redacción del propio proyecto. Durante la primera fase del proyecto, se realizó la búsqueda de información, tal y como se ha indicado con anterioridad. Tal búsqueda se elaboró a partir de libros y artículos cedidos gracias a la Universidad de Las Palmas de Gran Canaria o bien proporcionados por el equipo de investigación bajo el que se tuteló este TFT. Una vez obtenida toda la información requerida, se clasificó y estudió para la toma de los conocimientos requeridos para este experimento. El proceso de mantenimiento de los organismos, consiste en la preparación diaria del alimento de los mismos, así como, en el conteo general de organismos que hay en el cultivo. También se realiza la retirada de todo material particulado y/o excretado por los organismos del cultivo con el fin de evitar el aumento de la concentración de amonio, nitritos y nitratos en los acuarios de cultivo. Los misidáceos del cultivo son alimentados con Artemia, la cual se obtiene en cistes que se compran a una empresa privada. Una vez llegan los cistes, se procede a la descapsulación de los mismos para poder obtener los huevos, desde donde eclosionarán los organismos. Para la eclosión de la Artemia se necesita un tiempo de 24 horas; pasado dicho tiempo se le aporta Easy-DHA Selco® para enriquecer, nutricionalmente, los organismos. Tras 48 horas después de la eclosión, se realiza el recuento de Artemia en 1 ml de agua con una lupa binocular (Fig. 4) con el fin de conocer la concentración de dicho organismos y poder saber, de esta forma, la cantidad de agua connauplios de Artemia que hay que proporcionar a los misidáceos. Finalmente, y como parte esencial del proceso experimental, cada día se medían los misidáceos con una cámara réflex y mediante el software ImageJ, tal y como se menciona en el apartado “Material and methods” de este TFT. Estas medidas fueron procesadas, a través de la obtención de medias y desviaciones estándar, para la obtención de una curva de calibrado que relacionara el crecimiento (en longitud) con el tiempo. Por otro lado, algunos organismos eran sacrificados para poder obtener el peso seco y así poder adquirir la relación entre la longitud y el peso seco y, por lo tanto, lograr una curva de calibrado que relacionara el peso seco con el tiempo (debido a que Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 23 los modelos experimentales con los que se compararon los resultados obtenidos expresaban el crecimiento en peso seco y no en longitud). Tras haber elaborado la ecuación de la recta pertinente se procedió a su sustitución en el modelo matemático elaborado y en los modelos obtenidos de los autores, y su posterior comparación. Conforme se iban desarrollando y terminando los apartados del proyecto se procedía a la redacción correspondiente de los mismos, de tal forma que, la redacción de este TFT se ha llevado a cabo a la vez que el proceso experimental. I.II Formación recibida Aunque si bien podría no reconocerse como una formación, propiamente dicha, en este apartado puede ser considerable nombrar toda la información proporcionada para realizar el experimento, el aporte de manuales de cultivo tanto de Artemia como de misidáceos, así como, recomendaciones generales dentro del proceso meramente experimental. También es necesario nombrar cierta formación recibida en programación y tratamiento de datos, desarrollo de gráficos, etc. durante la realización de este TFT en los programas informáticos R, Matlab y Grapher. Así mismo, también se ha realizado un curso sobre cómo hacer exposiciones científicas en público. I.III Nivel de integración e implicación dentro del departamento y relaciones con el personal La integración dentro del departamento puede considerarse completa desde el comienzo del TFT. Desde el primer día se me suministró ayuda tanto a nivel bibliográfico como a nivel de material. Se me asignó la tarea de mantenimiento y limpieza del material de laboratorio usado por todo el equipo, así como los trabajos meramente directos de mi proyecto (que se describen en apartados anteriores). Mi incorporación dentro del grupo de investigación Ecofisiología de los Organismos Marinos (EOMAR) se realizó de manera inmediata. Éste funciona de forma muy colaborativa, ayudándose los unos a los otros en cualquier momento y resolviendo, con la mayor brevedad posible, todas aquellas dudas que pueden ir surgiendo a lo largo de la jornada. A nivel departamental, la integración puede definirse como óptima, siguiendo siempre un sistema basado en la cordialidad y el respeto, puedo declarar no haber tenido problema con ninguno de los investigadores y demás miembros del departamento de Biología en ningún momento, durante la realización de este TFT. Testing zooplankton secondary production against growth in the marine mysid, Leptomysis lingvura (G.O. Sars, 1866) 24 I.IV Aspectos positivos y negativos más significativos relacionados con el desarrollo del TFT A la hora de valorar los aspectos positivos y negativos del TFT, es conveniente ser lo más objetivo posible y dar las razones más coherentes en la puntualizaciones adjudicadas a cada una de las características del mismo. Entre los valores de la realización de un Trabajo de Fin de Título (a nivel general y no particularizando para el caso que aquí se presenta) destaca el hecho de aprender a elaborar trabajos de investigación, más propios de un científico que de un alumno y, por tanto, proporciona al alumno la posibilidad de ver que le espera en el mercado laboral de su carrera. Los TFT sirven además como plataforma de ampliación de conocimientos sobre el tema de interés del alumno, así como una manera de practicar y resolverse mejor en otros idiomas. Para el caso de este TFT en particular, quizás el mayor valor que presenta es la gran cantidad de conocimientos obtenidos sobre la biología, bioquímica y modelización matemática aplicable a los organismos zooplanctónicos. Entre las carencias más significativas de un TFT destaca el poco tiempo disponible para la realización del mismo, ya que el alumno no está acostumbrado a la realización de trabajos científicos de tal magnitud, el pequeño límite de tiempos de presentación del TFT disponible y el hecho de que todos los créditos en inglés de la carrera estén destinados a esta asignatura. I.V Valoración personal del aprendizaje conseguido a lo largo del TFT. Desde un punto de vista más personal se puede proceder a valorar el aprendizaje conseguido durante el desarrollo del TFT a través de la numeración de los valores adquiridos durante la realización del mismo. Los aspectos más generales se pueden resumir de la siguiente forma: 1) Aprender a organizar y ordenar de forma adecuada y coherente un trabajo de investigación científico en un tiempo determinado. 2) Lograr extraer la información necesaria para la realización de dicho trabajo y ser capaz de sintetizarlo en la medida de lo posible. 3) Ser capaz de resolver, objetivamente, los problemas que hayan podido surgir durante la realización del TFT. 4) Aprender a trabajar dentro de un equipo de investigación y de llevar a cabo tus propios logros y metas. 5) Poder ser reconocido por el trabajo realizado. 6) Ser capaz de presentar, en un idioma extranjero, y delante de un jurado, el trabajo realizado. En un nivel más relacionado con el presente TFT, se pueden denotar aspectos como: 7) Comprender el ciclo de vida y el comportamiento de los misidáceos en cultivo.