Table of Contents

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

Copepods were collected using a 250-um mesh plankton net with a solid cod end and then cultured in the laboratory for several generations. Adult female copepods from the laboratory culture were collected and split into two groups, one fed ad libitum and one provided with no food.  Upper thermal limits were then measured daily as the critical thermal maximum (CTmax) of individual copepods, or the temperature at which normal behavior ceases. CTmax measurements were made for individuals in both treatments for five days. These measurements are made during a gradual temperature ramp (at a rate of 0.1-0.3°C per minute). The CTmax methodology is described in Sasaki et al. 2023. Copepods are placed into 50 ml flat-bottom glass vials, which are immersed in a water bath. Temperatures are gradually increased using a 300 watt aquarium heater. Individual copepods are monitored throughout the temperature ramp until movement ceases, indicating the individual has reached its CTmax. The water temperature at that point is recovered from a continuous temperature record; three sensors are placed into separate vials in the water bath and record temperature every five seconds for the duration of the experiment. 

Organism identifiers (Life Science Identifier (LSID))
copepod, Acartia tonsa, urn:lsid:marinespecies.org:taxname:345943

The raw data and code used to measure CTmax are contained in the referenced GitHub repository https://github.com/ZoopEcoEvo/starved_ctmax (archival copy "ZoopEcoEvo/starved_ctmax: Initial release" doi: 10.5281/zenodo.8057949).

* Data from submitted file "Rueda-Moreno and Sasaki 2023.csv" was imported into the BCO-DMO data system for this dataset. Values "NA" imported as missing data values.   Table will appear as Data File: 955733_v1_a-tonsa-ctmax-feeding-exp.csv (along with other download format options).

Missing Data Identifiers:
* In the BCO-DMO data system missing data identifiers are displayed according to the format of data you access. For example, in csv files it will be blank (null) values. In Matlab .mat files it will be NaN values. When viewing data online at BCO-DMO, the missing value will be shown as blank (null) values.

* Date converted to ISO 8601 format

* Organism LSIDs added from matches at the World Register of Marine Species (WoRMS) on 2025-03-11

NSF Award Abstract:

Many parts of the ocean are warming rapidly, but it is still unknown how this warming will affect marine food webs. Copepods, small crustaceans, are the most abundant animals in the ocean; consequently, they play crucial roles in plankton marine food webs and in the transfer of energy to fishes. Many species of copepods are able to choose between prey such as microscopic plants and single-celled animals. The choice affects how energy moves through marine food webs. Past work suggests that increasing temperature should favor herbivory over carnivory. This project is investigating whether this prediction holds in the face of genetic adaptation to warming in highly seasonal systems such as coastal temperate zones. Results from this study are contributing to understanding and predicting the response of marine ecosystems to future climate conditions, as well as for planning and implementing sustainable fisheries management plans. Other broader impacts include the development of learning modules for high school and college students. Hands-on science exhibits for K-6 students and public presentations at established lecture series focus on the role of copepods in marine food webs in coastal habitats.

Predicting responses of the oceanic biota to climate change is limited not only by an incomplete understanding of how warming affects ecological interactions and evolutionary dynamics individually, but also by how these two factors interact. Copepods are both grazers of phytoplankton and predators of microzooplankton in marine systems. Increasing temperatures may drive a large-scale shift in the diet of omnivorous copepods towards stronger herbivory, with significant consequences for the structure of marine food webs and the control of primary productivity. However, thermal adaptation may moderate or even nullify these shifts. This project examines the interactive role ecological and evolutionary dynamics plays in shaping grazing and individual fitness in a warming ocean. The main goals of the project are to: 1) quantify seasonal variation in thermal performance curves in dominant coastal copepod species; 2) determine whether observed seasonal variation in thermal performance is caused by genetic differentiation or phenotypic plasticity; 3) assess how temperature affects respiration and protein synthesis rates, selective feeding, and individual fitness; and 4) determine how changes in the thermal performance curve, via both genetic differentiation and phenotypic plasticity, affect the relationship between temperature and food preference. Selective feeding experiments are being paired with measurements of egg production and hatching success across a wide range of temperatures to measure thermal effects on feeding selectivity and individual fitness. Finally, genetic differentiation and phenotypic plasticity on temperature sensitivity is being investigated across populations from environments that differ in their thermal regime. The outcomes of this project contribute to the parameterization of models that forecast fisheries dynamics in response to climate change.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.