Elias Kane Science Fair Final Draft I. Problem: Which environmental factor: pH, or the presence of the pesticide methoprene most inhibits the American lobster’s (Homarus americanus) growth rate as modeled by the Red Swamp crayfish (Procambarus clarkii)? II. Collected Information Long Island Sound serves as a prime habitat for thousands of species due to its relatively protected waters and stable environmental conditions. The American lobster (Homarus americanus) is one of the most integral scavengers of Long Island Sound. In addition, the American lobster is a backbone fishery of much of northeastern North America. Prior to 1999, in combined Connecticut and New York waters, the total lobster catch was between 7-11.7 million pounds. In 2004, the total lobster catch had fallen to 1.6 million pounds (Balcom &Howell, 2006, p. 1). This is due to a large American lobster die-off in late fall of 1999. Long Island Sound is in the southern extent of the American lobster’s range. Due to this fact, the temperature is considered likely to cause the organisms stress. Die-offs of the American lobster population have happened in the past, just never in the same magnitude as that of 1999 (Balcom & Howell, 2006, p. 5). Temperature as well as many other factors worked together to cause this particularly massive die-off. Several harmful variables in Long Island Sound led to the death of millions of lobsters. Climate change, in the form of temperature rise and ocean acidification, pesticide, shell disease, and parasitic amoebae which cause paramoebiasis, all led to this die-off (Balcom & Howell, 2006, p. 2). Paramoebiasis is a lethal disease that infects susceptible lobsters and eventually kills them. While the cause of death of the majority of the lobsters was proven to be paramoebiasis, there is still contention and debate over what was the most influential factor in its spread. Ocean acidification is a process in which our oceans absorb carbon dioxide from the air and store it as carbonic acid. This can cause basic shells to take longer to grow and develop in an acidic environment (“How to Take Care of Crayfish”, 2014). Shellfish and crustaceans thrive in basic or neutral waters due to the composition of their shells. The lobster and crayfish’s hard exoskeletons are made of calcium carbonate, a basic compound. The pH of ocean waters across the world are falling due to increased levels of carbon dioxide in the atmosphere. As the ocean Elias Kane Science Fair Final Draft becomes more acidic, its inhabitants are forced to migrate, adapt or die. Ocean acidification causes a basic exoskeleton to deteriorate. The summer of 1999 was riddled with cases of West Nile virus, which is transferable through mosquitoes. In an effort to abate the spread of disease, the government sprayed copious amounts of pesticide. In mid-September, Hurricane Floyd washed the pesticides and other lethal chemicals into Long Island Sound (Dellinger, 2012, p. 581). Reports of dead and dying lobsters surfaced just days later. Methoprene, the active ingredient in much of the sprayed pesticide, is a known toxin. It is supposed to target pests in their larval stage, but is truly indiscriminate in which species it kills. It is lethal to lobsters at one part per billion (Dellinger, 2012, p. 581). Lobstermen often blame methoprene and other pesticides for the fishery tragedy of 1999. Scientists, on the other hand, are split on the cause of this mysterious die-off. Some blame climate change, while others point fingers at pesticide, and several others blame an insurgence of epizootic bacteria and parasitic amoebae into Long Island Sound. Epizootic bacteria, the bacteria that causes lobster shell disease, thrives in warmer climates. In this way, climate change and shell disease are linked. Lobster shell disease is not a cause of death in lobsters. Instead, it opens up lesions in a shell and allows for the infection of opportunistic diseases. The warmer climate also allows for a heightened rate of spread of disease (Dellinger, 2012, p. 581). The contention over the cause of death in the die-off is still present to this day. Both the American lobster (Homarus Americanus) and the Red Swamp crayfish (Procambarus clarkii) are members of the subphylum Crustacea. Due to their common ancestry, they have similar physical and metabolic characteristics. In addition, they have similar reactions to environmental stressors (Reiber & McMahon, 1998, p. 168). They also possess analogous cardiovascular and respiratory systems. In environments with stressful conditions, both lobsters and crayfish at first start to hyperventilate. After getting used to the stressors, they go into lessened metabolic states (Reiber & McMahon, 1997, p. 168). The American lobster and the Red Swamp crayfish have many physiological and metabolic similarities. Both crustaceans react similarly to environmental stressors. Elias Kane Science Fair Final Draft III. Hypotheses a. If Procambarus clarkii is exposed to more acidic conditions, its growth will be the most stunted because it will slow down the growth of a crayfish’s basic shell. b. If Procambarus clarkii is exposed to methoprene, its growth will be the second most stunted and there will be a heightened mortality rate because it is lethal at small doses. c. If Procambarus clarkii is exposed to either environmental stressor, its growth rate will be lowered, relative to the control, because of the effects of methoprene and acid on crustaceans. IV. Experimental Design V. Procedure a. Collect materials i. 12 Procambarus clarkii specimens ii. 3 small tanks with space for 4 specimens marked one for each variable, and the control Elias Kane Science Fair Final Draft iii. Food for 12 crayfish for 1 month iv. Methoprene diluted to 1 ppb v. Carbonic acid vi. Caliper vii. Electronic balance viii. pH paper ix. micropipette x. micropipette tips xi. jar for toxic methoprene waste xii. 4.5 liters of dechlorinated water every other day b. Fill the tanks with 1.5 liters of dechlorinated water. c. Dilute methoprene to 1 part per 2 billion and add into a marked tank d. Add carbonic acid to the water of one of the marked tanks until the pH falls to 6, as determined by the pH paper. e. Leave one tank with pure dechlorinated water. f. Mass the crayfish in grams. g. Measure their length with calipers in centimeters (from eye to end of tail). h. Record the data. i. Feed each crayfish one sinking food pellet per day. j. Change the water in the tanks every two days, but maintain the environmental conditions. k. Mass and measure each crayfish at the zero, one, two, three, and four week marks. l. Record all data and graph. Elias Kane Science Fair Final Draft VI. Variables a. Independent Variables i. Methoprene ii. Acidity b. Dependent variable i. Growth of the crayfish per week c. Constants i. Dechlorinated water environment ii. Food amount iii. Food type iv. Shape and size of environment v. Water change frequency vi. Stage of life (juvenile) that the crayfish is in vii. The measurements used to determine growth d. Control i. The experiment conducted on crayfish without environmental stressors Elias Kane Science Fair Final Draft VII. Data Tables Table 1 Week Week Week Week Week Week # Control 0 1 2 3 4 Organism 1 .85 g .83 g .93g .90g .96g (Weight(g)/carapace 3cm 3.25 3.5cm 3.5cm 3.8cm length(mm) cm Organism 2 .48g .49g .49g .56g .58g 2.5cm 2.75cm 3cm 3.2cm 3.5cm Organism 3 .96g .93 1.01g 1.13g 1.13g 3.25cm 3.5 cm 4cm 4cm 4cm Organism 4 1.47g 1.38g 1.42g 1.65g 1.79g 4.2cm 4.2 cm 4.5cm 4.8cm 5cm Table 2 Week Week Week Week Week Week # Acid 0 1 2 3 4 Organism 1 1.60g 1.86g 1.93g 1.91g 1.85g (Weight(g)/carapace 4cm 4.2cm 4.5cm 4.5cm 4.5cm length(mm) Organism 2 1.33g 1.28g 1.30g 1.31g 1.33g 4cm 4cm 4.5cm 4.5cm 4.5cm Organism 3 1.84g 1.76g 1.84g 1.83g 1.78g 4.5cm 4.5cm 4.5 4.5cm 4.5cm cm Organism 4 0.79g .77 g .77g .84 g .76g 2.8cm 3.2cm 3.5cm 3.5cm 3.5cm Elias Kane Science Fair Final Draft Table 3 Week Week Week Week Week Week # Methoprene 0 1 2 3 4 Organism 1 2.49g 2.43g 2.49g 2.48g 2.47g (Weight(g)/carapace 5cm 5 cm 5cm 5cm 5cm length(mm) Organism 2 1.76g 1.83g 1.85g 1.77g 1.78g 4cm 4.2cm 4.5cm 4.5cm 4.7cm Organism 3 0.11g .17g .15g .12g .12 g 1.6cm 1.8cm 1.7cm 1.8cm 1.7cm Organism 4 1.22g 1.27g 1.33g 1.24g 1.23cm 3.8cm 4cm 4cm 4cm 4.2cm Elias Kane Science Fair Final Draft VIII. Graphs Fig. 1: Total Mass Growth of P. clarkii 0.2 0.18 0.16 0.14 0.12 0.1 0.08 Growth in Grams 0.06 0.04 0.02 0 1 Control Growth in Grams 0.175 Acid Growth in Grams 0.04 Methoprene Growth in 0.005 Grams Environmental Condi@on Elias Kane Science Fair Final Draft Fig. 2 Weekly Mass Growth (gm) of P. clarkii 0.12 0.1 0.08 0.06 0.04 0.02 0 -0.02 -0.04 Weekly Growth (gm) -0.06 1 2 3 4 Control Growth in Grams -0.0325 0.055 0.0975 0.055 Acid Growth in Grams 0.0275 0.0425 0.0125 -0.0425 Methoprene Growth in 0.03 0.03 -0.0525 -0.0025 Grams Week # Elias Kane Science Fair Final Draft Fig.