Abstract:

This study examines the impacts of near-future CO2 levels on early life stages of the yellowfin tuna (Thunnus albacares). Tuna embryos were obtained from a captive spawning broodstock population of yellowfin tuna at the IATTC Achotines Laboratory, Panama. Tuna were exposed to either control or 1900 microatmospheres CO2 directly after spawn and through the first 3 days of development as embryos hatched into yolk sac larvae. Metabolic rate, ammonia tissue accumulation, ammonia excretion, Rh protein mRNA expression, and specific gravity were quantified at various timepoints throughout development.

Suggested Citation:

Heuer, Rachael M., Yadong Wang, Christina Pasparakis, Vernon Scholey, Daniel Margulies, and Martin Grosell. 2020. Effects of elevated CO2 on ammonia excretion, metabolic rate, specific gravity, and yolk sac depletion in yellowfin tuna (Thunnus albacares) embryos and larvae. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/7Z48R4MC

Purpose:

To determine the effects of elevated CO2 on metabolic rate, ammonia excretion, and yolk sac depletion in yellowfin tuna (Thunnus albacares) embryos and larvae. The second purpose was to measure metabolic rate and ammonia excretion throughout development while documenting developmental stages using microscopy.

Data Parameters and Units:

Excel file: “Tuna carbon dioxide ammonia and urea tissue and flux” Excel file: “Tuna carbon dioxide mRNA expression data” Excel file “Tuna carbon dioxide oxygen consumption” Excel file: “Tuna carbon dioxide specific gravity” Excel file: “Tuna carbon dioxide yolk sac depletion and size of oil globule size” Excel file: “Tuna ontogeny ammonia and urea tissue and flux” Excel file: “Tuna ontogeny oxygen consumption” Folder containing jpegs “Tuna carbon dioxide images used for yolk sac depletion” Folder containing jpegs “Tuna developmental stage images”

Methods:

Methods: experimental animals and experimental treatment yellowfin tuna embryos were obtained from a captive breeding population at the Achotines Laboratory in Panama. Immediately after spawn, embryos were transferred to either control seawater or high-carbon dioxide seawater. Stable carbon dioxide levels were achieved using a Loligo pH-based negative feedback system (Loligo Systems). In this system, a standard curve was generated based on the relationship between known gas standards and seawater pH. Once a pH setpoint corresponding to 1900 microatmospheres carbon dioxide was calculated following calibration and measurement of ambient seawater, one hundred percent carbon dioxide was gassed directly into flow-through tanks via solenoid valves controlled by pH electrodes (Sentix H, wtw) and a pCO2/pH DAQ-M digital relay instrument connected to CapCTRL software (Loligo Systems) to achieve the desired pCO2 setpoint. Independent pH measurements were taken multiple times a week using a separate pH electrode (pHNBS, PHC3005, Radiometer). Target carbon dioxide levels were confirmed with measurements of seawater total carbon dioxide using a Corning 965 CO2 Analyzer (Corning 965). Embryos were sampled throughout development for measurements of oxygen consumption, yolk sac depletion, ammonia content, ammonia excretion flux, and specific gravity. Specific timepoints for each of these measurements are noted in associated sections for each measurement below. See readme for more details.

Instruments:

Corning 965 CO2 Analyzer; CapCTRL software

Provenance and Historical References:

Ivancic, Ingrid and Danilo Degobbis. 1984. An optimal manual procedure for ammonia analysis in natural waters by the indophenol blue method. Water Research 18(9): 1143-1147. doi:10.1016/0043-1354(84)90230-6 Boyde, Tom R.C. and Mohammed Rahmatullah. Optimization of conditions for the colorimetric determination of citrulline, using diacetyl monoxime. 1980. Analytical Biochemistry 107(2):424-431. doi:10.1016/0003-2697(80)90404-2 Zhao, Sheng and Russell D. Fernald. 2005. Comprehensive algorithm for quantitative real-time polymerase chain reaction. Journal of Computational Biology 12(8):1047–1064. doi: 10.1089/cmb.2005.12.1047

Individual Files: