Rapid adaptation to road salts in a freshwater microbial eukaryote

Freshwater habitats in parts of the world that get snow and ice are experiencing increased salinity due to the use of road salts. We used experimental evolution to test how the ciliate Tetrahymena thermophila, which is endemic to the northeastern United States and a key player in the microbial food web, will adapt to increasing salinity. Populations of T. thermophila were evolved in either no salt or constant or increasing concentrations of NaCl or MgCl2, two of the most commonly used road salts. Following about 175 generations of evolution all populations were tested for survival and growth in different salt concentrations. We found that Tetrahymena adapt quickly to survive and grow better in increasing salinity with the IC50 increasing significantly in populations grown in the highest salt concentrations. However, populations adapted to the highest salts also experienced fitness tradeoffs when grown in salt-free conditions. These results demonstrate the rapidity with which microb..., , # Data from: Rapid adaptation to road salts in a freshwater microbial eukaryote

Dataset DOI: [10.5061/dryad.vhhmgqp6v](10.5061/dryad.vhhmgqp6v)

## Description of the data and file structure

Data are output from microbial growth assays on a 96-well microplate reader.

### Files and variables

**Files labeled \"assay\"** are OD650 values from a 96-well Tecan SUNRISE microplate reader.

The prefix to \"assay\" indicates the assay condition:

SSP = no salt

Na9 = 9 g/L NaCl

Na18 = 18 g/L NaCl

Mg5 = 5 g/L MgCl~2~

Mg17 = 17 g/L MgCl~2~

Measurements were taken every 10 minutes for 6 days. Time column is in seconds.

**Files labeled \"plate\"** contain information on which ciliate populations were in each well for a given assay condition, e.g. Mg5_plate shows which populations were in each well of the Mg5_assay.

Populations are identified by evolution condition \_ replicate population number \_ measurement replicate.

An = ancestor

Co = control, evolved in no salt

Nc = evolved in constant N..., ,