We put in a proposal earlier this year to look at the effects of a large point source of heavy metal pollution in north Birmingham on microbial populations, and today we collected our first field samples. Alex, Charlie, Sarah, and Jeff went to Greenwood Park, just to the southwest of the Birmingham airport, where we paced off an approximately 50×50 m quadrat in a sparsely wooded field at the corner of 16th Ave and Coosa St.
You can see the study site in the bottom left corner. We selected 6 sites at random within this quadrat. At each site, Charlie collected a plug or two of soil and put them in Ziploc bags to bring back to the lab.
Pro tip: Ziploc bags come out of the box sterile!
We also identified the nearest tree to each randomly chosen site. In most cases, the tree wasn’t actually very near, but 5 or 10 m away. We sampled two sides of each tree — one side facing toward the heavy metal point source, and the other side facing away. Specifically, we sampled the bark surface microbial community using sterile cotton swabs dipped in sterile saline solution, which yielded more than 5x as much DNA as other sampling methods in Alex’s preliminary trials.
We also collected about 10 g of bark with a pocketknife.
We will send both bark and soil samples off for trace metal analysis here at UAB.
I’ll follow up over the next few days with our workflow for processing these samples. All in all, it was a fun day — nice to get out of the lab for once, even though it was 91 outside.
(all photos and artwork by Sarah Adkins)