Place any object in the ocean and within a few hours, a thin film of microorganisms begins to form on its surface. In days’ time, a complex, symbiotic community of marine life is flourishing. This ‘biofilm’ world, however, often hinders research below the waves.
Consortium faculty and students from institutions across Rhode Island are learning more about the microbial makeup of these biofilm communities, with an ultimate eye towards lessening the impact on marine sensors and finding novel ways to remove biofilm from equipment without harming the environment.
“It’s been millions of years and these bacteria have found a way to adapt, so our task in checking their growth is difficult,” says Dr. Vinka Oyanedel-Craver, associate professor of civil and environmental engineering at the University of Rhode Island.
How does a biofilm community form?
When an object like a sensor buoy is placed in the ocean, says Dr. Anne Reid, assistant professor of biology and biomedical sciences at Salve Regina University, ‘first colonizers’latch onto the surface and begin to create chemical by-products that attract other organisms.
“Those first colonizers are usually much better at sticking to less hospitable surfaces,” she explains. “The bacteria then produce polysaccharides (a carbohydrate made of multiple sugar molecules) that increase the stickiness of a surface, allowing other microbes to attach.”
Biofilm research: a three-pronged approach
The Consortium’s biofilm research is being conducted through three separate projects. Craver and graduate student Kayla Kurtz have set up controlled tests at both Roger Williams University’s Marine Biology Wetlab and the University of Rhode Island’s Marine Science Research Facility. Kurtz has cultured biofilm communities on plates made of polydimethylsiloxane (PDMS), a clear, rubbery material being used by Consortium researchers to case marine sensors that will ultimately be deployed in Narragansett Bay.
“Once the bacteria and biofilm start to show, I then examine it with nano-scale microscopes,” details Kurtz, who worked with Xiaojie Liu, a mechanical engineering graduate student at URI, to create a custom PDMS test plate. “The challenge is trying to identify the bacteria and biomolecules showing up on the PDMS.”
Polysacccharide n. a carbohydrate produced by early colonizing bacteria that forms a sticky film on an underwater surface
Dr. Christopher Reid, associate professor of science and technology at Bryant University, is working alongside colleague Keyana Roohani to catalog bacteria extracted from samples of biofilm grown in Narragansett Bay. This database has been created through metagenomics, or the identification of species and their chemical characteristics through DNA sequencing.
“When we did our literature review, Chris and I found that there haven’t been any studies on biofilm in the northeast United States,” admits Roohani. “So, we said, ‘let’s figure it out’.”
Anne Reid’s work focuses on understanding the geographical distribution of biofilm bacteria in marine communities across Narragansett Bay.
“How some bacteria develop biofilm in Wickford Cove, for example, could be very different than in another part of the Bay, so we are trying to isolate and characterize those individual species and test their interactions with different surfaces,” she explains. “From those tests, we produce simplified biofilms in the lab using microbes we know are present in Narragansett Bay, learning how to prevent biofilms from forming or disrupt them once they are formed.”
A view towards prevention
Once Craver and her team have sufficiently captured the makeup and dynamics of Narragansett Bay’s biofilm communities, the research will focus on developing effective strategies to slow down bacteria and other organisms in ways that not only allow marine sensing equipment to do its job, but also reduce the use of potentially harmful anti-fouling techniques. These strategies will be tested on equipment from the Consortium’s Bay Observatory.
“Once we understand the diverse species within biofilm and where the Consortium will put its chemical sensors in the Bay, then we can incorporate our research into developing cleaning procedures,” says Craver. “The hope is to prevent biofilm from forming on sensors for the longest time possible, but in the end, we will need to use multiple strategies of prevention and cleaning to deter the bacteria and other organisms from growing.”