10 Aug 2016

Humans Are Poisoning The Ocean—And It’s Poisoning Us Back

Nika Knight

It’s no secret that we have trashed, poisoned, and warmed oceans at an unprecedented rate via human-caused climate change and pollution.
It seems that oceans may be paying us back in kind, according to a new study that found levels of bacteria responsible for life-threatening illnesses spiking in the North Atlantic region.
The study published Monday in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) discovered that a deadly variety of bacteria known as vibrio is spreading rapidly throughout the Atlantic as a result of hotter ocean temperatures.
Marine ecologist Donald Boesch, president of the University of Maryland Center for Environmental Science, who was not involved in the research, described the shift to theWashington Post as “an ecosystem-level effect of climate change”:
What this new research does is present evidence of the increased prevalence of these bacteria over broad regions of the North Atlantic from preserved samples collected over 54 years. The prevalence of these bacteria has increased as the ocean has warmed, both as result of global warming and multi-decadal variations in ocean circulation.  This trend may be caused by changes in the plankton community rather than just the temperature alone.  In other words, increased prevalence may be an ecosystem-level effect of climate change.
Vibrio bacteria cause infections in humans and animals, and a growing number of people are hospitalized each year after consuming fish contaminated by the pathogen, the study notes, observing that the rapid rise in vibrio levels on the U.S. and European Atlantic coasts corresponds with the increasing number of hospitalizations for vibrio infections on both continents.
“We were able to demonstrate that there was an increase in the numbers of vibrios, probably a two or threefold increase, correlated with the increase in climate temperature, and then correlated with outbreaks of vibrio infections that have been recorded in the medical records,” said Rita Colwell, a microbiologist at the University of Maryland who is a co-author of the study, to the Post.
Colwell told the Post that the shift in vibrio bacteria numbers is just one of many enormous ecological transformations to come as a result of climate change. “It’s a disruption of the natural pattern, and it will be selecting for a number of species, and that’s the problem,” Colwell said.
“We don’t just damage the oceans even as we ourselves go unaffected by the consequences of that damage,” the Post observes. “Rather, from harm to fisheries to direct human health threats, that damage hurts us, too.”

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