Dataset: Ocean warming & acidification experiment: Acartia hudsonica survival

Three hundred copepods were collected in April of 2018 from eastern Long Island Sound, Connecticut, USA (41.3°N, 72.0°W) and raised for one year (~12 generations) (14 degrees Celsius (°C), 400 microatmospheres (μatm) CO2, 30 ‰ salinity, 12:12 hours light:dark) as stock cultures to limit maternal effects (Falconer, 1989, Introduction to Quantitative Genetics). Three resulting stock cultures with >2,000 individuals each were combined and then split evenly into three groups for each of the four treatments. Groups were acclimatized within a generation to temperature (15°C or 13°C, 1°C per day) and pCO2 (1000 μatm, 100 μatm per day, OA treatments only). Groups seeded the F0 individuals for 7-10 days yielding ~15,000 eggs per treatment. Resulting F0 eggs and nauplii were combined for each treatment, redistributed among three replicate cultures, and returned to their respective experimental conditions. The experimental environmental conditions were: 1) Ambient control (AM): 13°C, 400 µatm CO2, pH = 8.2; 2) Ocean Acidification (OA): 13°C, 1000 µatm CO2, pH = 7.85; 3) Ocean Warming (OW): 15°C, 400 μatm CO2, pH = 8.2; 4) Combined warming and acidification (OWA): 15°C, 1000 μatm CO2, pH = 7.85. Copepods were fed equal proportions of the live phytoplankters Tetraselmis sp., Rhodomonas sp., and Thalassiosira weissflogii every 48-72 hours to achieve food-replete conditions (≥600 micrograms (μg) Carbon per liter (L)) (Feinberg and Dam, 1998. Marine Ecology Progress Series), deliberately raised under ambient conditions to avoid confounding effects of possible food quality changes.

Survival was measured from nauplius 1 (N1) to copepodid 6 (C6; adult). For a given generation, all adults from the previous generation were removed from the culture and allowed to lay eggs in food-replete media for 48 hours. Resulting nauplii were chosen for tracking survival. Unhatched eggs and any nauplii not chosen for survival analysis were returned to their respective cultures for continued population maintenance. To measure survival, three 250 milliliter (mL) beakers for each replicate culture were supplied with 25 randomly chosen N1 nauplii each and housed in the plexiglass enclosure (n= 9 per treatment). Copepods were checked every 48-72 hours. The number of dead, live, and missing copepods was recorded for each beaker along with developmental stage (nauplius, copepodite, adult female, or adult male). Nauplii were grown with media at levels of 250 μg C L-1 for the first four days to prevent overgrowth of phytoplankton and allow for adequate nauplii grazing. Then, copepods were grown with food-replete media. For food limitation experiments in F11, the three beakers for each replicate culture were split evenly between the three food concentrations. Food media was replaced on monitoring days. Average survival probabilities were calculated for each replicate culture at each generation as the proportion of surviving individuals on monitoring days.