Fellow to Study How Livestock Antibiotics Affect Nutrient-Balancing Microbes

Could State-of-the-Art Management Make Shellfish Disease Problems Worse?
May 17, 2016
Collaboration is Key in Sea Level Rise Resiliency Planning at 12th Adaptation Forum
May 24, 2016
Show all

Fellow to Study How Livestock Antibiotics Affect Nutrient-Balancing Microbes

Miguel Semedo will study how antibiotics fed to livestock affect microbes.

Miguel Semedo.

Miguel Semedo. ©VASG

By Chris Patrick, staff writer

Miguel Semedo thinks microbes get a bad rap.

“A lot of people relate bacteria or fungi to disease or other negative things,” says Semedo, graduate student at Virginia Institute of Marine Science (VIMS). “But microbial organisms perform important ecosystem services. They’re amazing.”

Microscopic bacteria and fungi play all kinds of critical roles in the environment, but human activities might be threatening their ability to do certain jobs. This June, Semedo begins a three-year research fellowship with Virginia Sea Grant to see how antibiotics used by the livestock industry on Virginia’s Eastern Shore affect microbes that help balance nutrients in the environment.

Antibiotics designed to kill bacteria spread from livestock farms to the natural environment. Large-scale livestock farming operations often feed their animals antibiotics to enhance growth and prevent disease. Animals don’t completely break down the antibiotics, so it ends up in feces. Through runoff, these antibiotics spread to creeks and other waters, where microbes are exposed to them.

A class of microbes exposed to the antibiotics are called denitrifiers. They live in the sediment at the bottom of a creek and turn nitrate, a nitrogen-containing compound found in soil and water, into nitrogen gas, the main component of our atmosphere. In doing so, denitrifiers remove some of the excess nitrogen that can cause harmful algal blooms. But livestock antibiotics might be harming these nitrogen-balancing microbes.

On Virginia’s Eastern Shore, poultry farms raise millions of chickens per year in a small land area. Virginia Eastern Shorekeeper, an organization that seeks to protect Virginia’s Chesapeake Bay and Atlantic waters, wants to know how existing and new poultry houses affect nearby water quality.

Semedo will provide part of the answer as he investigates if exposure to livestock antibiotics is compromising denitrifiers’ ability to change nitrate into benign nitrogen gas.

“I plan to work in collaboration with the Virginia Eastern Shorekeeper and try to give them the best scientific data as I can to show them the potential environmental impacts of these operations,” Semedo says.

Semedo’s collaborative and open approach to science began with an inspiring high school biology teacher. She told him that science was like an open box: the knowledge inside is meant to be shared.

“So advancing knowledge and sharing it has always been very exciting to me,” he says.

Semedo is currently earning his doctorate from VIMS. He received a bachelor’s degree in biochemistry in 2008 and a master’s degree in same subject in 2009 at University of Porto in Porto, Portugal, which is also his hometown.