Founded in 1930, of Chicago Shed Aquarium Not just a popular tourist attraction. Its staff also assists with conservation efforts around the world and conducts essential research on animal health and behavior, nutrition, genetics, aquatic filtration, and molecular and microbial ecology. Over the past four years, those employees have been puzzled by the mysterious disappearance of an antiparasitic drug routinely added to the water in the aquarium’s quarantine habitat. Now, with the help of microbiologists from Northwestern University, they have solved the case. The culprit: About 21 members of a family of microbes who regularly chewed medicine in the water, according to a recent paper Published in the journal Science of the Total Environment.
The Aquarium’s Conservation and Research Center includes an Animal Care and Science Division, which has a state-of-the-art animal hospital to monitor the health of all animals and the treatment they require. (If you want to know how to give an MRI to an electric eel, the center’s team has you covered.)
Since 2015, the center has been working on a special research project examining the aquarium microbiome. Among other topics, the project involves studying microbial communities in aquarium bio-filters. Such closed aquatic systems can quickly become toxic due to ammonia waste from fish, and some microbial communities may help keep those levels under control. But other microbes are less beneficial, as the case of the missing chloroquine shows.
Whenever the Shed Aquarium acquires new animals, the organisms are first placed in the quarantine habitat to prevent them from introducing any external pathogens to the carefully controlled environment of the aquarium. Part of that process involves the administration of chloroquine phosphate, usually by adding it to housing water. Staff regularly monitored chloroquine concentrations, so they noticed that those concentrations were usually much lower than expected—often too low to serve as an effective antiparasitic.
Co-authors Erica M. from Northwestern University. Enter Hartmann and his fellow microbial detectives. They took water samples from the quarantine residence, as well as swab samples from the walls and pipes of the residence. They brought the samples back to their lab for comprehensive analysis. All told, they counted about 754 different microbes that called the habitat home, and the team quickly guessed that the chloroquine thief was among them.
“Obviously, there are germs in the water, but there are also microbes that stick to the edges of surfaces,” Hartman said, “If you’ve ever had an aquarium at home, you’ve probably noticed the grime on the sides. People sometimes use snails or algae-eating fish to help clean up the sides. So, we put whatever’s in the water.” and wanted to study whatever was stuck on the edges of the surfaces.”
Next, the researchers had to trace the suspects. First, they took cultures of each microbe and gave each only chloroquine as food. Alas, those results didn’t narrow the field so much. But their chemical analysis of the remaining chloroquine revealed an important clue: It was missing all nitrogen.
“Carbon, nitrogen, oxygen and phosphorus are the basic necessities that everything needs to live.” Hartman said, “In this case, it seems that the microorganisms were using the drug as a source of nitrogen. When we examined how the drug was degraded, we found that the piece of the nitrogen-containing molecule was gone. Eating it Pickles from just one cheeseburger and leaves the rest behind.”
After all, Hartmann and others, were able to identify 21 potential culprits that thrived in housing pipes, some of which had not been studied before. It’s still unclear which of them is scavenging all the nitrogen in chloroquine, but at least the aquarium now knows the problem lies in the pipes. Unfortunately, simply flushing those pipes regularly probably won’t fix the problem, as the germs tend to stick firmly to the sides. According to Hartmann, the housing’s pipes will need to be cleaned or possibly replaced entirely. Switching between freshwater and seawater could help keep microbial populations under control in the future.
The authors conclude, “Overall, our results expand the body of knowledge surrounding the aquarium microbiome and veterinary drug degradation, by revealing how microbial ecology and chemistry should be integrated into the future management of circulating seawater enclosures.” can be done.” “Furthermore, these findings may highlight events in other nitrogen-limiting environments when nitrogen-containing anthropogenic chemicals are added.”
DOI: The Science of the Total Environment, 2021. 10.1016/j.scitotenv.2021.150532 (About DOI).