Abstract

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−1. Food resources categorized as high (H, >1 µg L−1) and low (L, <1 µg L−1) levels, and pH-values categorized as equivalent to present day (≤400 µatm pCO2, pH > 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.

Details

Title
Antagonistic interplay between pH and food resources affects copepod traits and performance in a year-round upwelling system
Author
Aguilera, Victor M 1   VIAFID ORCID Logo  ; Vargas, Cristian A 2 ; Dam, Hans G 3 

 Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Bernardo Ossandón #877, Coquimbo, Chile ; Universidad Católica del Norte, Facultad de Ciencias del Mar, Depto. Biología Marina, Coquimbo, Chile (GRID:grid.8049.5) (ISNI:0000 0001 2291 598X) ; Universidad de Concepción, Instituto Milenio de Oceanografía, Concepción, Chile (GRID:grid.5380.e) (ISNI:0000 0001 2298 9663) 
 Universidad de Concepción, Instituto Milenio de Oceanografía, Concepción, Chile (GRID:grid.5380.e) (ISNI:0000 0001 2298 9663) ; Faculty of Environmental Sciences and Environmental Sciences Center EULA Chile, Universidad de Concepción, Aquatic Ecosystem Functioning Lab (LAFE), Department of Aquatic Systems, Concepción, Chile (GRID:grid.5380.e) (ISNI:0000 0001 2298 9663) ; Universidad de Concepción, Center for the Study of Multiple-drivers on Marine Socio-Ecological Systems (MUSELS), Concepción, Chile (GRID:grid.5380.e) (ISNI:0000 0001 2298 9663) 
 University of Connecticut, Department of Marine Sciences, Groton, USA (GRID:grid.63054.34) (ISNI:0000 0001 0860 4915) 
Publication year
2020
Publication date
2020
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2342980651
Copyright
This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.