Effect of increasing sea water pCO sub(2) on the northern Atlantic krill species Nyctiphanes couchii

• Published in: Marine biology Vol. 161; no. 10; pp. 2359 - 2370
• Main Authors: Sperfeld, Erik, Mangor-Jensen, Anders, Dalpadado, Padmini
• Format: Journal Article
• Language: English
• Published: 01.10.2014
• Subjects: Marine; Nyctiphanes; ANE, Norway, Hordaland, Bergen
• ISSN: 0025-3162; 1432-1793
• DOI: 10.1007/s00227-014-2511-x

Surprisingly little is known about potential effects of ocean acidification on krill of the Northern Hemisphere as ecologically very important food web component. Sub-adult individuals of the northern Atlantic krill species Nyctiphanes couchii (caught at Austevoll near Bergen, Norway, in January 2013) were exposed in the laboratory to four different levels of pCO sub(2) (430, 800, 1,100, and 1,700 mu atm) for 5 weeks in order to assess potential changes in a set of biological response variables. Survival decreased and the frequency of moulting-related deaths increased with increasing pCO sub(2). Survival was considerably reduced at relatively high pCO sub(2) of 1,700 mu atm and tended to be negatively affected at 1,100 mu atm pCO sub(2). However, the experimental results show no significant effects of pCO sub(2) on inter-moult period and growth at pCO sub(2) levels below 1,100 mu atm. No differences in length measurements of the carapace and uropod were observed across pCO sub(2) levels, indicating no effect of changing carbonate chemistry on the morphology of those calciferous parts of the exoskeleton. The results suggest that sub-adult N. couchii may not suffer dramatically from predicted near-future changes in pCO sub(2). However, potential detrimental effects on the moulting process and associated higher mortality at 1,100 mu atm pCO sub(2) cannot be excluded. Further experiments are needed in order to investigate whether early life stages of N. couchii show a different sensitivity to elevated sea water pCO sub(2) and whether those results are transferable to other krill species of the Northern Hemisphere.