DOI: 10.5061/dryad.wm37pvmvb
title: Developmental temperature, more than long-term evolution, defines thermal tolerance in an Estuarine Copepod

description: 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 &gt;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 (one generation), three generations, and
 &gt;40 generations of warming increased thermal tolerance compared to
 Ambient conditions, with development in OW resulting in equal thermal
 tolerance to three and &gt;40 generations of OW. Strikingly,
 developmental OW and &gt;40 generations of OW had no effect on low
 salinity tolerance relative to Ambient. By contrast, when environmental
 salinity was reduced first, copepods had lower thermal tolerances. These
 results highlight a critical role for plasticity in the copepod climate
 response and suggest that salinity variability may reduce copepod
 tolerance to subsequent warming.
description: # **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 of the
 data and file structure** In **UCONN_ULT_Final** there are six variables:
 Line, Replicate, Treatment, Group, Condition, and ULT. These variables are
 defined below. * Line: Categorical variable with two levels, Control and
 HighTemp. Control line animals were from UConn lines held at 18C and
 HighTemp line animals were from UConn lines held at 22C. * Replicate: This
 categorical variable has four levels referring to which replicate line
 animals originated from. * Treatment: Categorical variable with two levels
 Ambient and OceanWarming. Animals at Ambient were held at 18C at the time
 of the upper lethal temperature assay. Animals at OceanWarming were held
 at 22C at the time of the upper lethal temperature assay. * Group: Six
 level categorical variable defining each unique combination of line and
 treatment. * Condition: This variable is redundant to Group, with a
 different naming scheme for analysis in R. * ULT: Continuous variable,
 upper lethal temperature values for individual copepods. In
 **UCONN_LLS_Reps_NoTreat** there are six variables: Line, Replicate,
 Group, Condition, Treatment, and OLLS. These variables are defined below.
 * Line: Categorical variable with two levels, Ambient and HighTemp.
 Ambient line animals were from UConn lines held at 18C and HighTemp line
 animals were from UConn lines held at 22C. * Replicate: This categorical
 variable has four levels referring to which replicate line animals
 originated from. * Treatment: Categorical variable with two levels 18 and
 22. Animals at 18 were held at 18C at the time of the upper lethal
 temperature assay. Animals at 22 were held at 22C at the time of the upper
 lethal temperature assay.  * Group: Six level categorical variable
 defining each unique combination of line and treatment. * Condition: This
 variable is redundant to Group, with a different naming scheme for
 analysis in R. * OLLS: Observed lower lethal salinity for each individual
 copepod. In **SalinityTemp** there are three variables: Population,
 Salinity, and ULT. * Population: Categorical variable with two levels: HB,
 and UCONNControl. HB represents animals collected in Hammonasset Beach
 State Park, CT. UCONNControl represents animals from the UConn originating
 ambient line animals held at 18C. * Salinity: This is a categorical
 variable with three levels. Each level represents the salinity treatment
 copepods were exposed to in ppt. * ULT: This is a continuous variable
 representing the upper lethal temperature of each individual copepod.
 **LHS_ctmax_Complete** is a dataset with six variables: Population, Plate,
 Stage, Ctmax, Sex, and MeanMax. * Population: Categorical variable with
 three levels: Maine, NewYork, and Florida. * Plate: Categorical variable
 with three levels, designating which six well plate animals were in. *
 Stage: Categorical variable with three levels: Adult, Copepodite, and
 Nauplii. These are the life history stages copepods were at when they were
 assessed for their upper lethal temperature. * Ctmax: This is a continuous
 variable with upper lethal temperature values for each individual copepod.
 * Sex: Categorical variable with three levels: Male, Female, and Unknown.
 * MeanMax: Mean maximum temperature collected from buoys near each
 population site. In **UCONN_GradualSalinity_Trial** there are five
 variables: Line, Condition, Replicate, Sex, and LLS. * Line: Categorical
 variable with one level, Control. These represent animals that originated
 from UConn control line held at 18C. * Condition: This is a categorical
 variable with one level, High. This represents that the animals were held
 at 22C during the salinity trial. * Replicate: This is a categorical
 variable with one level, 2. This represents the replicate line the animals
 originated from. * Sex: Categorical variable with two levels: Male and
 Female. This represents the sex of the individual copepod in the salinity
 trial. * LLS: This is a continuous variable for the lower lethal salinity
 of each individual copepod. **Code/Software** Code can be found at this
 Github repository: