IMIS | Flanders Marine Institute
 

Flanders Marine Institute

Platform for marine research

IMIS

Publications | Institutes | Persons | Datasets | Projects | Maps
[ report an error in this record ]basket (0): add | show Printer-friendly version

Responses of Leptasterias hexactis (Echinodermata: Asteroidea) to low salinity: II. Nitrogen metabolism, respiration and energy budget
Shirley, T.C.; Stickle, W.B. (1982). Responses of Leptasterias hexactis (Echinodermata: Asteroidea) to low salinity: II. Nitrogen metabolism, respiration and energy budget. Mar. Biol. (Berl.) 69(2): 155-163
In: Marine Biology. Springer: Heidelberg; Berlin. ISSN 0025-3162, more
Peer reviewed article  

Available in  Authors 

Keywords
    Energy budget; Nitrogen metabolism; Respiration; Asteroidea [WoRMS]; Leptasterias hexactis (Stimpson, 1862) [WoRMS]; Marine

Authors  Top 
  • Shirley, T.C.
  • Stickle, W.B.

Abstract
    Respiration and excretion rates were measured for Leptasterias hexactis (Stimpson, 1862) that had been gradually exposed to 30, 20 and 15(permil) S. These rates were integrated with feeding, absorption efficiency and growth rates of the same starfish to develop energy budgets and indices of physiological stress for them at the different salinities. Salinity had significant effects on respiration, with the rates at 30(permil) S being significantly higher than the rates at the lower salinities. Salinity did not affect total nitrogen excretion rates. Ammonia was the major excretory product, but urea and primary amines were excreted in significant amounts. The oxygen:nitrogen ratio varied directly with salinity and significant differences were found between the rate at 30permil S and the two lower salinities. Both gross (K1) and net (K2) growth efficiency varied directly with salinity. No significant differences existed between the means of either K1 or K2 at 30 or 20(permil) S, but both were significantly higher at 30 and 20(permil) S than at 15(permil) S. Scope for growth (SG), the caloric balance after metabolic expenditures, varied directly with salinity and significant differences existed between the means at all salinities. The effectiveness of SG as a predictor of growth was verified by comparison to actual growth measurements. The ability of L. hexactis to maintain positive SG for 3 wk in the laboratory at 20(permil) S is indicative of tolerance to hyposmotic stress and may partially explain its success in habitats subjected to seasonal reductions of salinity.

All data in IMIS is subject to the VLIZ privacy policy Top | Authors