Effects of environmental hypercapnia on animal physiology: A 13C NMR study of protein synthesis rates in the marine invertebrate Sipunculus nudus

Abstract

Global climate change is associated with a progressive rise in ocean CO 2 concentrations (hypercapnia) and, consequently, a drop in seawater pH. However, a comprehensive picture of the physiological mechanisms affected by chronic CO 2 stress in marine biota is still lacking. Here we present an analysis of protein biosynthesis rates in isolated muscle of the marine invertebrate Sipunculus nudus, a sediment dwelling worm living at various water depths. We followed the incorporation of 13 C-labelled phenylalanine into muscular protein via high-resolution NMR spectroscopy. Protein synthesis decreased by about 60% at a medium pH of 6.70 and a consequently lowered intracellular pH (pHi). The decrease in protein synthesis rates is much stronger than the concomitant suppression of protein degradation (60% versus 10-15%) possibly posing a threat to the cellular homeostasis of structural as well as functional proteins. Considering the progressive rise in ocean CO 2 concentrations, permanent disturbances of cellular protein turnover might seriously affect growth and reproductive performance in many marine organisms with as yet unexplored impacts on species density and composition in marine ecosystems.

Moderate seawater acidification does not elicit long-term metabolic depression in the blue mussel Mytilus edulis

“…A reduced capacity to form matrix structures might in turn have adverse effect on the deposition of calcium carbonate crystals. It has been previously described that elevated pCO 2 has an impact on protein turnover in several marine organisms leading to lowered synthesis or even enhanced degradation (Langenbuch and Pörtner 2003;Langenbuch et al 2006;Wood et al 2008). On the other hand, it cannot be excluded that the progressively more acidic environment of the extrapallial fluid (c.f.…”

Tribute to P. L. Lutz: putting life on `pause' – molecular regulation of hypometabolism

“…specific biochemical inhibition of metabolic activities). Several studies have indicated that extrinsic parameters can account for a significant portion of overall metabolic inhibition (Barnhart and McMahon, 1988;Guppy et al, 2000;Langenbuch et al, 2006;Michaelidis et al, 2007).…”

Defective skeletogenesis and oversized otoliths in fish early stages in a changing ocean

“…Ocean acidification is considered a major threat to marine organisms as it may lead to acid-base balance disturbances, protein biosynthesis decrease, metabolic depression and growth reduction (Seibel and Walsh, 2001;Pörtner et al, 2004;Langenbuch et al, 2006;Rosa and Seibel, 2008;Baumann et al, 2012). Exposure to elevated CO 2 particularly affects calcifying organisms (Orr et al, 2005;Dupont et al, 2008;Fabry et al, 2008;Talmage and Gobler, 2010), although detrimental effects on survival, growth and respiratory physiology of non-calcifying marine animals have also been observed (Seibel and Walsh, 2001;Rosa and Seibel, 2008;Munday et al, 2009b).…”