MARINE 106 LAB REPORT
Elena Shippey
Curtis Fahey
MAR 106-L B
12 March 2019
An Analysis of Respiration Rates of the Common Periwinkle (Littorina littorea), Clam Worm (Nereis virens) and Scud (Gammarus oceanicus) in Saco Bay, Maine
Abstract
Organisms carry out cellular respiration as a method of producing ATP to do cell work. It is likely that environment affects an organism’s respiration rate, as well as characteristics of the organism itself. We hypothesized that marine organisms in cold water would have higher rates of cellular respiration than organisms in warm water. We also hypothesized that the larger an organism’s size/more complex an organism’s body is, the higher their metabolic rate would be, expecting to see Nereis virens with the highest rate, Littorina littorea the lowest rate, and Gammarus oceanicus somewhere in the middle. One of each organism was placed in cold and warm water chambers to test how oxygen consumption changed over time. A dissolved oxygen reading was taken every 30 minutes for 120 minutes. Data were compiled and analyzed by creating a figure. Data showed that there is a significant relationship between temperature and respiration rate, and that different species do vary in metabolic rates. Results showed that respiration rates were higher in warm water replicates than cold water, and that large size and/or greater body complexity may also be linked to higher respiration values. In future years, ocean warming may potentially influence oxygen levels.
Introduction
Cell metabolism includes all required reactions for proper cell function. Endergonic reactions require an energy input in the usable form of ATP. This energy form is a product of cellular respiration, where oxygen and glucose are taken in to release water and carbon dioxide. Approximately 36 ATP are generated for every glucose in cellular respiration. The rate at which an organism undergoes cell respiration reflects its overall metabolic rate. Metabolic rate can fluctuate based on environmental factors, such as change in water temperature for a marine organism (Biswas, Pradip K. et al 2006). Metabolic rate may also be linked to an organism’s body size or complexity. We hypothesized that organisms in cold water would have a higher respiration/metabolic rate than organisms in warm water. Additionally, among the three ectotherms Littorina littorea, Nereis virens, and Gammarus oceanicus, we hypothesized that cellular respiration rates would be higher in organisms with larger, more complex body systems rather than small, simple systems (Ikeda 110). Thus, N. virens would have the highest respiration rate, G. oceanicus would have a mid-range respiration rate, and L. littorea the lowest respiration rate.
Materials and Methods
Six organisms were obtained from the rocky intertidal environment of Biddeford Pool in Saco Bay, Maine.: two L. littorea, two N. virens, and two G. oceanicus. After taking dry mass, organisms were placed into BOD bottles of seawater. The bottles were kept at two distinct temperatures: cold (4-8℃) and warm (20-25℃). An initial dissolved oxygen reading was taken using a DO meter (representing 0 minutes). DO readings were taken every 30 minutes for two hours, for a total of five readings per bottle. Between readings, the cold treatment bottles were kept on ice and the warm bottles left out. After taking the last reading, data were compiled to represent change in of DO in mg/L over the 120 minute period.
Results
All six organisms showed a decrease in DO over the 120-minute period, regardless of water temperature or species. Generally, warm water treatment trials experienced greater oxygen consumption than the cold water treatment vials, regardless of species. The species with the largest oxygen consumption rate was N. virens, followed by G. oceanicus and L. littorea with the smallest oxygen consumption. A t-Test statistical analysis test was conducted for each organism, comparing warm and cold treatments; each t-Test had 8 degrees of freedom.
Table 1. p-values of G. oceanicus, L. littorina, and N. virens based on student t-Test statistical analysis tests. Critical value of 1.86; 8 degrees of freedom.
| Organism | p-value |
| G. oceanicus | 0.117 |
| L.littorina | 0.0362 |
| N.virens | 0.209 |
Discussion
Figure 1 demonstrates a direct relationship between water temperature and oxygen consumption. An increase in metabolic rate resulted in a higher demand of oxygen to keep up with the body’s processes, meaning that more oxygen was removed from its environment to be utilized for the organism’s metabolism (Rani 2016). Based on graphic results, the first portion of the hypothesis was rejected, which expected cold water to increase the organism’s metabolic rate. Increased metabolism in warm waters can be explained by the organisms being ectotherms. Ectotherms use their environment to regulate their temperature, which thus influences their metabolic rate. An increase in temperature of the surrounding environment will increase the organism’s metabolism, vice versa. The second half of the hypothesis, regarding species, was supported by the data. N. virens had the highest metabolic rate, followed by G. oceanicus and lastly L. littorea. These results are likely related to the size of the organism, N. virens being the largest and L. littorea being the smallest. The larger the organism, the greater the oxygen demand to carry out metabolic processes such as cellular respiration in the organism. Although the conclusion reflects Figure 1, graphic results do not align with statistical values. The only species that was statistically significant based on the student t-Test was L. littorina, which was the least biologically/graphically significant. N. virens, which showed the greatest difference graphically, was not statistically significant. In order to come to a reasonable conclusion, both biological and statistical significance should be considered. These results can further future studies regarding metabolic rates of marine organisms. As the earth’s oceans continue to warm, increasing ectotherm metabolism, future oxygen levels in the water may be at risk.
References
Rani, Sudesh. 2016. Effect of Water Temperature on Respiratory Rate of Fish, Cirrhinus Mrigala. Indian Journal of Fundamental and Applied Life Sciences. 6(2):1-3.
Biswas, Pradip K., Cherkasov, Anton S., Ridings, Daisy M., Ringwood, Amy H., Sokolova, Inna M. 2006. Effects of acclimation temperature and cadmium exposure on cellular energy budgets in the marine mollusk Crassostrea virginica: linking cellular and mitochondrial responses. Journal of Experimental Biology. 2006(209): 1274-1284.
Ikeda, Tsutomu. 1970. Relationship Between Respiration Rate and Body Size in Marine Plankton Animals as a Function of the Temperature of Habitat. Hokkaido University Collection of Scholarly and Academic Papers. 21(2): 91-112.
