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Tamari Alexander- Campbell Alexis Brown Olivia Woodfox Adventures in Labster : Marine Biology

This week on Adventures in Labster, the talented trio must work with an environmental investigator to determine the cause of a massive fish-killing. In order to investigate the mysterious fish massacre, the following actions were taken: ➢ Collection of fish and water samples ➢ Fish necropsy ○ Careful analysis of species, length, and weight of sample ○ Condition of fish assessed including presence of lesions, parasite biopsy, and areas of coloration ○ Hypothesis : death by suffocation

➢ State of water assessed using dissolved oxygen analysis ○ Using spectrophotometry It was the first day of spring break and Drs. Alexander- Campbell, Brown, and Woodfox were enjoying the sun rays of Miami, Florida. They arrived at the Sunnyside Aquarium where they were preparing to swim with the dolphins. To their dismay, the manager announced that all excursions had been postponed due to a newly formed crime scene. Thinking that they were about to witness a live action NCIS episode, they went searching for more details. However,

upon investigating they met Dr. Johnson, a marine biologist, who explained there was a mysterious massacre involving hundreds of fish. A little less enthused, the doctors agreed to help her solve the case in hopes that they could resume their vacation as soon as possible. The doctors began by taking fish and water samples from the aquarium. A dead fish was collected as well as water from the coral reef they inhabited. After a careful analysis Dr. Alexander Campbell noticed a few inhabit abnormalities in the fish that was collected. There was a red, focal, and irregular lesion that was located on the posterior side. Focal refers to a localized spot rather than spread all over, also known as diffused. Looking more closely at the lesion Dr. Alexander Campbell decided to examine the organs and noticed the gills were abnormally dark red. This led to the doctors to worry because normally the gills would have been a bright, cherry red which is a sign of a healthy functional gills. The necroscopy report stated due to the dark gills , it indicates suffocation. This could have been caused by numerous factors. One of which could be due to oxygen levels, sometimes the level of oxygen will drop drastically where it can not support the aquatic life in which this particular fish populates. Another reason we can think about is trauma related, this is dealing with fishermen, predation, and explosive shock. However, with the evidence we collected we came to believe that the fish was suffocated due to the dissolved oxygen levels. Meanwhile, Dr. Woodfox examined the water sample using indigo carmine, a coloring agent, in order to measure the concentration of dissolved oxygen. The color intensity indicated a dissolved oxygen level of 2. To confirm their finding, Dr. Brown set up the spectrophotometer by running a blank cuvette to guarantee accuracy. Afterwards, she ran a sample of the water which was observed to have an absorbance level of 0.24. Using a calibration curve, the doctors agreed that there was a dissolved oxygen level of 1.86. As environmental specialists, the doctors agreed that the water temperature factored into their findings. Conclusion Drs. Alexander- Campbell, Brown, and Woodfox successfully proved their hypothesis in which

the cause of the massive fish killing was death by suffocation. The experimental results show that the area has low dissolved oxygen levels due to warmer waters which relates to the color intensity. The reduced form of indigo carmine reacted with the dissolved oxygen to form a blue product. Through many collected samples and much observation, it was shown that the indigo carmine presented an increase in blue color intensity with the dissolved oxygen level. Preliminary results showed that using a spectrophotometer would allow the specialists to obtain more accurate data. The doctors were finally able to get back to their spring break shenanigans and received a year’s membership to the aquarium for their amazing detective work!...