title: Acid-base balance and changes in haemolymph properties of the South African rock lobsters, Jasus lalandii, a palinurid decapod, during chronic hypercapnia.
abstract: Few studies exist reporting on long-term exposure of crustaceans to hypercapnia. We exposed juvenile South African rock lobsters, Jasus lalandii, to hypercapnic conditions of pH 7.3 for 28 weeks and subsequently analysed changes in the extracellular fluid (haemolymph). Results revealed, for the first time, adjustments in the haemolymph of a palinurid crustacean during chronic hypercapnic exposure: 1) acid-base balance was adjusted and sustained by increased bicarbonate and 2) quantity and oxygen binding properties of haemocyanin changed. Compared with lobsters kept under normocapnic conditions (pH 8.0), during prolonged hypercapnia, juvenile lobsters increased bicarbonate buffering of haemolymph. This is necessary to provide optimum pH conditions for oxygen binding of haemocyanin and functioning of respiration in the presence of a strong Bohr Effect. Furthermore, modification of the intrinsic structure of the haemocyanin molecule, and not the presence of molecular modulators, seems to improve oxygen affinity under conditions of elevated pCO2.
authors: Department of Animal Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa. Electronic address: jarredmail@yahoo.com.
authors: Jarred L
authors: JL
authors: Knapp
authors: Institute of Metabolic Physiology, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany. Electronic address: bridges@hhu.de.
authors: Christopher R
authors: CR
authors: Bridges
authors: Institute of Metabolic Physiology, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany. Electronic address: janina.krohn@aol.com.
authors: Janina
authors: J
authors: Krohn
authors: Department of Animal Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa. Electronic address: LCH@sun.ac.za.
authors: Louwrens C
authors: LC
authors: Hoffman
authors: Department of Animal Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa; Branch: Fisheries Management, Department of Agriculture, Forestry and Fisheries, Roggebaai 8012, South Africa. Electronic address: Lutz.Auerswald@gmail.com.
authors: Lutz
authors: L
authors: Auerswald
mesh_terms: D000136:Acid-Base Equilibrium; D000818:Animals; D002908:Chronic Disease; D003445:Crustacea / Q000378:metabolism*; D006433:Hemocyanins / Q000378:metabolism; D006458:Hemolymph / Q000378:metabolism*; D006935:Hypercapnia / Q000097:blood*; D010100:Oxygen / Q000097:blood
chemical_list: D006433:Hemocyanins; D010100:Oxygen
keywords: Acid-base balance; Chronic hypercapnia; Haemoprotein haemocyanin; Molecular structure change; Ocean acidification