Rising water temperatures endanger health of coastal ecosystems

photo of man and woman in lab, with beakers

Hollibaugh teaser.jpgIncreasing water temperatures are responsible for the accumulation of the chemical nitrite in marine environments throughout the world, a symptom of broader changes in normal ocean biochemical pathways that could ultimately disrupt ocean food webs, according to new marine science research:

Nitrite is produced when microorganisms consume ammonium in waste products from fertilizers, treated sewage and animal waste. Too much nitrite can alter the kinds and amounts of single-celled plants living in marine environments, potentially affecting the animals that feed on them, said James Hollibaugh, co-author of the study published recently in Environmental Science and Technology. It also could lead to toxic algal blooms and create dead zones where no fish or animals can live. 

"Rising ocean temperatures are changing the way coastal ecosystems-and probably terrestrial ecosystems, too-process nitrogen," said Hollibaugh, Distinguished Research Professor of Marine Sciences in UGA's Franklin College of Arts and Sciences. "Much of the global nitrogen cycle takes place in the coastal zone."

Hollibaugh and researcher Sylvia Schaefer found midsummer peaks in concentrations of nitrite alongside massive increases in numbers of the microorganisms that produce it in the coastal waters off Sapelo Island, Georgia, in data collected over the course of eight years. Although most researchers believe nitrite accumulation is a consequence of oxygen deficiency in a marine environment, Hollibaugh and Schaefer thought something else had to be driving the accumulation.

Our researchers on campus and at the Skidaway Institute are working to inform people, businesses and governments along the coast and beyond about the many implications of warming waters on the delicate ecology of our barrier islands and the oceans that feed them.

Image: Marine biologists James Hollibaugh and Sylvia Schaefer, by Andrew Davis Tucker for UGA.