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Aquatic hypercapnia and aerial excretion of CO 2 in air‐breathing fishes
Author(s) -
Jew Corey,
Thomsen Mikkel,
Bayley Mark,
Hicks James W
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.760.25
Subject(s) - gill , hypercapnia , excretion , fish <actinopterygii> , ventilation (architecture) , environmental science , biology , environmental chemistry , chemistry , ecology , respiratory system , anatomy , fishery , endocrinology , meteorology , physics
The notion that bimodal breathers (animals that breathe both air and water) obtain O 2 from the air and exhale CO‐ 2 into the water has been well established in the literature. However, while the majority of supporting experiments tested animals maintained in hypoxic water, freshwater systems that bimodal breather inhabit have been reported to be hypercapnic as well. Data from 3 air‐breathing fishes show that when in hypercapnic water, excretion of CO 2 into the air does increase, but the majority of CO 2 is still released into the water. To maintain a downward diffusion gradient for CO 2 from the gills to the water, a high blood PCO 2 must also be sustained. Our data suggest in aquatic hypercapnia, air‐breathing fish are unable regulate blood PCO 2 below that of the water. This is likely due to low ventilation at the air‐breathing organ and high surface area contact with water at the gills. Support or Funding Information Society for Experimental Biology, American Physiological Society