Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
  • BCO-DMO Processing Description
• Data Files
• Related Publications
• Related Datasets
• Parameters
• Project Information
• Funding

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.

The population net reproductive rate, λ, was calculated as the dominant eigenvalue of an assembled projected age-structured Leslie matrix constructed from survival and fecundity data (Caswell, H. 2001. Matrix Population Models: Construction, Analysis, and Interpretation). Briefly, day-specific probabilities of survival are calculated from day-specific survival as Px = l­x / (lx-1) where lx represents the proportion of individuals on day x and lx - 1 represents the proportion of individuals on day x - 1. Probabilities of survival on day 1 are assumed to be 100%, or a value of 1.0. Per capita EPR and HS are calculated as described in the preceding, with fecundity rates equalling the product of EPR and HS. Because only females produce offspring, total fecundity rates must be scaled to the sex ratio (proportion of females to males). To account for differences in individual development time for each treatment, fecundity rates are assigned to all days after the first matured adult is observed. We assume that surviving individuals represented by the survival experiments are equally as likely to experience any of the fecundity values observed in EPR experiments. Therefore, each mate-pair fecundity rate was paired with each survival beaker to construct a matrix. This yields a maximum of 120 matrices per treatment per generation (3 survival beakers × 4 replicate cultures × 10 mate pairs). Full methods for all traits can be found in: deMayo, et al. 2023. Simultaneous warming and acidification limit population and reveal phenotype costs for a marine phenotype. Proc. R. Soc. B 290: 20231033. doi.org/10.1098/rspb.2023.1033

All data analysis and processing were performed with R (v 4.0.2). Code for data analysis and visualization can be found at: https://zenodo.org/badge/latestdoi/505896789.

- Imported original file "lambda_results_devtime_surv_epr_hf_sex_w_f11.txt" into the BCO-DMO system.
- Renamed fields to comply with BCO-DMO naming conventions.
- Saved final file as "923960_v1_a_hudsonica_population_fitness.csv".

NSF Award Abstract:
Over time, our oceans are becoming both warmer and higher dissolved carbon dioxide. The latter condition is called ocean acidification. The consequences of these simultaneous changes for populations of marine organisms are not well understood. For this project, the investigators will conduct a series of laboratory experiments to determine how two closely-related, common species of Acartia copepods will respond to the interactive effects of warming and acidification and also how well these species can adapt over multiple generations to changing ocean conditions. Since these copepods are key species in coastal food webs, results will have important implications for understanding and predicting how marine ecosystems may respond to future climate change. The investigators will share results from the research through traditional print media, case studies, and video mini lectures. The goal will be for educators of all levels to easily access material on climate change and ocean acidification to include in teaching curricula, in alignment with recommendations for universal design for learning. The project is a collaborative effort between an established professor at the University of Connecticut and an early-career female scientist at the University of Vermont. It will provide training and opportunities for collaborative, interdisciplinary research for two postdoctoral investigators, two graduate students and an undergraduate student.

The project's main goals are: 1) to test the simultaneous effects of temperature and carbon dioxide under current and future conditions on life history traits throughout the life cycle for two key copepod species, warm-adapted Acartia tonsa and cold-adapted Acartia hudsonica; 2) to test for adaptive capacity of both copepod species to a warmer and carbon-dioxide-enriched ocean; 3) to measure the genetic and maternally-induced changes across multiple generations of experimental selection in future conditions in both copepod species, and to identify the genes and pathways responding to selection. The investigators will use experiments encompassing current and projected temperature and carbon-dioxide conditions, will determine the roles of each variable and their interaction on traits that affect the fitness of both copepod species. They will also determine which life stages are most sensitive to individual or simultaneous stress conditions. Through multigenerational selection experiments, the investigators will identify and characterize the mechanisms of copepod evolutionary adaptation. Finally, they will measure genomic changes across the generations under all four experimental conditions to quantify the relative contributions of genetic and maternally-induced change in the physiological and life history traits of copepods in response to near-future climate conditions.