Developmental temperature, more than long-term evolution, defines thermal tolerance in an Estuarine Copepod

Climate change is resulting in increasing ocean temperatures and salinity variability, particularly in estuarine environments. Tolerance of temperature and salinity change interact and thus may impact organismal resilience. Populations can respond to multiple stressors in the short-term (i.e., plasticity) or over longer timescales (i.e., adaptation). However, little is known about the short- or long-term effects of elevated temperature on the tolerance of acute temperature and salinity changes. Here we characterized the response of the near-shore and estuarine copepod, Acartia tonsa, to temperature and salinity stress. Copepods originated from one of two sets of replicated >40 generation-old temperature adapted lines: Ambient (AM, 18°C) and ocean warming (OW, 22°C). Copepods from these lines were subjected to one and three generations at the reciprocal temperature. Copepods from all treatments were then assessed for differences in acute temperature and salinity tolerance. Development..., , , # **Developmental temperature, more than long-term evolution, defines thermal tolerance in an estuarine copepod**

DOI: 10.5061/dryad.wm37pvmvb

This dataset contains five data files. The first data file contains results from an experimental evolution study in the copepod, *Acartia tonsa*. In this study we examined the effect of ocean warming on the upper lethal temperature  of *A. tonsa*. The second file contains results from the same study, where we instead looked at the impact of ocean warming on lower lethal salinity. In the third file, we examined the impact of rapid salinity change on upper lethal temperature in the copepod *A. tonsa*. The last two files contain supplementary data that were used for supplemental figures. These files contain data from preliminary experiments where upper lethal temperature and lower lethal salinity were tested.

1\)  UCONN_ULT_Final
2\)  UCONN_LLS_Reps_NoTreat
3\)  SalinityTemp
4\)  LHS_ctmax_Complete
5\)  UCONN_GradualSalinity_Trial

**Description ...