Some very interesting studies are now staring to emerge using DNA analysis to study the presence and distribution of bacteria in cities like New York. One such study revealed the presence of marine bacteria in a NYC subway station, probably as a result of previous flooding due to superstorm Sandy (see: Post-Sandy NYC Subway Brims with Unknown Microbes). Below is an excerpt from the article:
Researchers identified nearly 1,700 species of bacteria, viruses and eukaryotes to create a “metagenomic” map of the city. One cluster of points on this grid offered a reminder of exactly how inundated and overwhelmed the city was more than two years ago when Superstorm Sandy hit. Nearly half of the mapped DNA came from as-yet undocumented organisms, highlighting how much remains unknown to science about the microbial world around us. The results are detailed in ,,,[a recent study]. ....The most commonly identified DNA in the sample came from bacteria. And although strains of the causative agents of anthrax and bubonic plague surfaced, the vast majority of species identified were harmless....[The author of the study] says these dangerous DNA snippets occurred only at trace levels, so they could have been fragments that other bacteria picked up through horizontal gene transfer or even have come from dead organisms. Most of the bacteria identified are types that placidly thrive on our skin and are of no concern ....But researchers found one of the [subway] stations was not like the others. The South Ferry station in Lower Manhattan had the most unique profile of bacteria in the system, and still resembled a marine environment. When the storm surge from Hurricane Sandy hit the city in 2012, the station filled with about 57 million liters of water that rose to 25 meters deep....The researchers isolated 10 bacterial species that were only found at South Ferry. Among these were Shewanella frigidimarina, which has been found in the North Sea, and Flavobacterium, which can harm certain species of fish. The unique bacteria are usually found in cold, marine environments, so the researchers wondered if Sandy's storm water dragged them in.
Here's another quote that makes reference to this same microbiology DNA study (see: Big Data and Bacteria: Mapping the New York Subway’s DNA):
The big-data project, the first genetic profile of a metropolitan transit system, is in many ways “a mirror of the people themselves who ride the subway,” said Dr. Mason, a geneticist at the Weill Cornell Medical College. It is also a revealing glimpse into the future of public health. Across the country, researchers are combining microbiology, genomics and population genetics on a massive scale to identify the micro-organisms in the buildings and confined spaces of entire cities.
For me, an interesting aspects of this study is the suggestion that marine organisms might be able to thrive in a "dry" NYC subway station unless the DNA detected is merely residual from dead organisms or related to horizontal gene transfer to other bacteria. If, in fact, these marine bacteria are growing in the South Ferry subway station, one wonders if there are any possible adverse health consequences. However, I suppose that most New Yorkers would consider bacterial growth as one of the lesser threats encountered in subway stations.