Seawater carbonate chemistry and copepod traits and performance

• Main Authors: Aguilera, Victor M, Vargas, Cristian A, Dam, Hans G
• Format: Dataset
• Language: English
• Published: PANGAEA 2020
• Subjects: Acartia tonsa; Alkalinity; total; Animalia; Antofagasta_OA; Aragonite saturation state; Arthropoda; Behaviour; Bicarbonate ion; Body size; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chlorophyll a; Coast and continental shelf; DATE/TIME; Depth; bottom/max; top/min; water; Egg production rate per female; EXP; Experiment; Field observation; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Ingestion rate of chlorophyll a per day per individual; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; Registration number of species; Reproduction; Salinity; Single species; South Pacific; Species; Temperate; Temperature; Type; Uniform resource locator/link to reference; Ocean acidification; Copepods
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.925337; https://doi.org/10.1594/PANGAEA.925337

Linking pH/pCO2 natural variation to phenotypic traits and performance of foundational species provides essential information for assessing and predicting the impact of ocean acidification (OA) on marine ecosystems. Yet, evidence of such linkage for copepods, the most abundant metazoans in the oceans, remains scarce, particularly for naturally corrosive Eastern Boundary Upwelling systems (EBUs). This study assessed the relationship between pH levels and traits (body and egg size) and performance (ingestion rate (IR) and egg reproduction rate (EPR)) of the numerically dominant neritic copepod Acartia tonsa, in a year-round upwelling system of the northern (23° S) Humboldt EBUs. The study revealed decreases in chlorophyll (Chl) ingestion rate, egg production rate and egg size with decreasing pH as well as egg production efficiency, but the opposite for copepod body size. Further, ingestion rate increased hyperbolically with Chl, and saturated at 1 µg Chl/ L. Food resources categorized as high (H, >1 µg/L) and low (L, 7.89) and future (>400 µatm pCO2, pH < 7.89) were used to compare our observations to values globally employed to experimentally test copepod sensitivity to OA. A comparison (PERMANOVA) test with Chl/pH (2*2) design showed that partially overlapping OA levels expected for the year 2100 in other ocean regions, low-pH conditions in this system negatively impacted traits and performance associated with copepod fitness. However, interacting antagonistically with pH, food resource (Chl) maintained copepod production in spite of low pH levels. Thus, the deleterious effects of ocean acidification are modulated by resource availability in this system.