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

Differences in ion regulation in the sea urchins Lytechinus variegatus and Arbacia lixula (Echinodermata: Echinoidea)
Vidolin, D.; Santos-Gouvea, I.A.; Freire, C.A. (2007). Differences in ion regulation in the sea urchins Lytechinus variegatus and Arbacia lixula (Echinodermata: Echinoidea). J. Mar. Biol. Ass. U.K. 87(3): 769-775. dx.doi.org/10.1017/S0025315407054124
In: Journal of the Marine Biological Association of the United Kingdom. Cambridge University Press/Marine Biological Association of the United Kingdom: Cambridge. ISSN 0025-3154, more
Peer reviewed article  

Available in Authors 

Keyword
    Marine

Authors  Top 
  • Vidolin, D.
  • Santos-Gouvea, I.A.
  • Freire, C.A.

Abstract
    The regular sea urchin Lytechinus variegatus, a species previously reported from areas of reduced salinities, and Arbacia lixula, a species unreported from diluted waters, were submitted to seawater dilution or seawater dilution in magnesium-supplemented waters. Seawater (35 psu) was either proportionally diluted with filtered dechlorinated tap water (30 psu, 25 psu), or diluted and supplemented with magnesium as MgCl2 (30+Mg, 25+Mg), up to full-strength seawater Mg2+ levels (35 psu, ~54 mM Mg2+ ). Magnesium supplementation was intended to verify the interfering effect of magnesium on osmo-ionic concentrations of the coelomic fluid (CF) of two ecologically distinct species of sea urchins. After 6 h in control (35 psu) or experimental seawater, CF samples were withdrawn by puncturing through the peristomial membrane. Coelomic fluid osmolality ([Osm]), and concentrations of ([Na+]), ([Cl-]), ([Mg2+ ]) and ([K +]) were measured for both species. Under all conditions, L. variegatus displayed higher CF osmolality, [Na+], and [K+] values than the water (and A. lixula). Comparatively, L. variegatus is designated as a'hyper-conformer', while A. lixula is an 'iso-conformer'. The CF [Mg2+ ] showed no evidence of being controlled by either species. Mg2+ supplementation in diluted seawater affected Mg2+ and Cl- levels only. Na+ appears to be taken up actively by L. variegatus, rendering its CF mostly hyper-ionic for Na+ (and hyperosmotic) relative to external seawater. The different gradients observed with the different ions suggest selective permeabilities or ion regulation by L. variegatus.

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