Open AccessElevated pCO2 and hypoxia alter the acid-base regulation of developing sheepshead minnows Cyprinodon variegatus
Author(s) -
LA Enzor,
Cheryl Hankins,
M. Hamilton-Frazier,
Elizabeth Moso,
Sandy Raimondo,
MG Barron
Publication year - 2020
Publication title -
marine ecology. progress series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.151
H-Index - 188
eISSN - 1616-1599
pISSN - 0171-8630
DOI - 10.3354/meps13220
Subject(s) - hypoxia (environmental) , juvenile , biology , eutrophication , oxidative stress , hatching , zoology , ecology , nutrient , chemistry , oxygen , biochemistry , organic chemistry
Low dissolved oxygen and increased acidification are two environmental variables that concomitantly change in an estuarine environment, both of which are exacerbated by nutrient pollution and subsequent eutrophication. To better understand how estuarine residents compensate for daily fluctuations in these environmental variables, the interactive effects of acidification and hypoxia were assessed in developing sheepshead minnows ( Cyprinodon variegatus ) using a 2 by 2 factorial design over a 42-day exposure. Embryos were exposed to either acidic (partial pressure of CO 2 , p CO 2 , ~2000 μatm), hypoxic (reduced dissolved oxygen, ~2 mg l -1 ), or combined acidic and hypoxic conditions and monitored for development, hatch rate, and survival. Changes in oxygen consumption, anaerobic metabolism, oxidative stress, and acid-base balance were evaluated at three life stages (embryo, larval, and juvenile fish) to discern if and how fish compensate for these stressors during development. The combination of acidification and hypoxia delayed hatching in embryos and significantly decreased oxygen consumption (p<0.001) in all three life-stages. Neither acidification, hypoxia, nor the combination of the stressors impacted the anaerobic metabolism or oxidative stress of juvenile fish, but acid-base equilibrium was disrupted by all three treatments in larval fish. Elevated carbonic anhydrase activity was observed in the multi-stress treatment in embryos and larval fish, but not in juvenile fish. These results show that developing sheepshead minnows can re-establish cellular homeostasis in compensating to acidified and hypoxic waters.