With the increase of carbon dioxide in the atmosphere due to human activity, the ocean suffers. Ocean temperatures rise as more fossil fuels are burned, leading to decreases in pH levels and causing the world’s waters to become more acidic.
A returning member of the SURF program, Juwaan Douglas-Jenkins is closely studying the impact of ocean acidification on the Narragansett Bay ecosystem. His summer project builds off of his previous research on biofilm, or a community of microbes that adhere to a surface, like a rock or in your body, and can be found in almost any environment.
“Originally I was characterizing the microbes in Narragansett Bay in the summer of 2019. I began by identifying isolates and determining their biofilm strength in order to test anti-biofouling” says Juwaan, a senior at Salve Regina University working under Dr. Anne Reid, assistant professor of biology.
Over the past years, Juwaan has collected and identified 60 different microbes, each of which he was able to grow and isolate to test their biofilm-forming capabilities.
“Now what I am hoping to do is try to identify acid tolerant bacteria and just continue building up our microbe collection,” he says.
Every organism thrives in an environment that has a specific pH. The pH scale ranges from 0 to 14, with 7 being neutral. Anything lower than 7 is considered acidic while anything higher than 7 is basic. If that environment is altered, those species might die off. Due to ocean acidification, acid-tolerant organisms are becoming overrepresented in marine environments. This is a problem because larger organisms that depend on other microorganisms, such as bacteria, will begin to starve without enough available bacteria from normal pHs levels.
“Acid-tolerant species are likely to become overrepresented in the microbial communities, which will alter the function of these communities and the marine ecosystem as a whole,” says Juwaan. “So, it will have a significant effect on the food web. Not to mention bacteria are important for certain processes such as nitrogen fixation and photosynthesis.”
“Acid-tolerant species are likely to become overrepresented in the microbial communities, which will alter the function of these communities and the marine ecosystem as a whole. So, it will have a significant effect on the food web." -Juwaan Douglas-Jenkins, 2021 SURF
After collecting water samples from Narragansett Bay, Juwaan first begins an experiment by creating a low nutrient acidic media for his cell culture dish, or a Petri dish. The purpose of low nutrient acidic media is to provide support for the growth of specific bacteria by giving a steady amount of nutrients that allows select bacteria to reproduce quickly.
Once the broth has been developed, Juwaan then introduces the biofilm bacteria. And, after seven days of waiting, he can determine how much biofilm has grown. Acid-tolerant microbes will then be isolated and identified through genetic techniques such as 16S rRNA sequencing.
“After collecting a water sample, one of the ways that we process the water is filtering it through filter paper," he says. "The filter paper is then placed onto our plate with the low nutrient acidic media. So we let them grow until they’re able to form colonies, which are little circles in a Petri dish that can vary in color, size, and shape."
Once you have your colonies growing, you want to isolate the different types of colonies. These pure isolates are sent out to be sequenced to figure out what genus they belong to and from there we can perform different tests to learn more about them.”
As a returning SURFer, Juwaan mentions that COVID was a pretty big challenge for him.
“Last year I had family responsibilities that prevented me from being able to work over the summer," he says. "However, I am thankful that I was able to continue my research throughout the school year even though it was challenging trying to balance research and classes."
Looking beyond the SURF program, Juwaan hopes to continue to medical school.
“From my experience working as a dietary aid, I knew that I wanted to pursue a career in healthcare," he says. "I did become an EMT, but I also want to learn more. I never expected that I would fall in love with research. So, I decided to pursue an MD-PhD program in order to combine both of my interests in patient care and research."
For now, however, the Salve Regina senior is focused on publishing a paper on his biofilm research with mentor, Dr. Reid.
This story was written by Ciara French, a 2021 Summer Undergraduate Research Fellow (SURF) for the Rhode Island Consortium for Coastal Ecology Assessment, Innovation, and Modeling. She is a rising senior at the University of Rhode Island majoring in biomedical engineering.
This material is based upon work supported in part by the National Science Foundation under EPSCoR Cooperative Agreement #OIA-1655221. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.