Elevated CO2 increases energetic cost and ion movement in the marine fish intestine

Energetic costs associated with ion and acid-base regulation in response to ocean acidification have been predicted to decrease the energy available to fish for basic life processes. However, the low cost of ion regulation (6–15% of standard metabolic rate) and inherent variation associated with whole-animal metabolic rate measurements have made it difficult to consistently demonstrate such a cost. Here we aimed to gain resolution in assessing the energetic demand associated with acid-base regulation by examining ion movement and O2 consumption rates of isolated intestinal tissue from Gulf toadfish acclimated to control or 1900 μatm CO2 (projected for year 2300). The active marine fish intestine absorbs ions from ingested seawater in exchange for HCO3− to maintain water balance. We demonstrate that CO2 exposure causes a 13% increase of intestinal HCO3− secretion that the animal does not appear to regulate. Isolated tissue from CO2-exposed toadfish also exhibited an 8% higher O2 consumption rate than tissue from controls. These findings show that compensation for CO2 leads to a seemingly maladaptive persistent base (HCO3−) loss that incurs an energetic expense at the tissue level. Sustained increases to baseline metabolic rate could lead to energetic reallocations away from other life processes at the whole-animal level.

Heuer R. M. & Grosell M., 2016. Elevated CO2 increases energetic cost and ion movement in the marine fish intestine. Scientific Reports 6:34480. Article.

0 Responses to “Elevated CO2 increases energetic cost and ion movement in the marine fish intestine”

  1. Leave a Comment

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

Subscribe to the RSS feed

Powered by FeedBurner

Follow AnneMarin on Twitter

Blog Stats

  • 1,075,524 hits


Ocean acidification in the IPCC AR5 WG II

OUP book