The effect of light on oxygen consumption in two amphipod crustaceans–the hypogean Niphargus stygius and the epigean Gammarus fossarum

Abstract

The effects of light on the metabolic rates of the hypogean amphipod Niphargus stygius and the epigean amphipod Gammarus fossarum were compared by measuring oxygen consumption and respiratory electron transport system (ETS) activity. They were exposed to light intensities of 720 and 4700 lx at 10°C. Oxygen consumption increased significantly in N. stygius exposed to both low and high intensities of light, but no significant increase was observed in G. fossarum at either intensity. The increase of oxygen consumption in N. stygius was significantly greater at the higher light intensity. This indicates a stress response in which exploitation of half the metabolic potential for energy production in N. stygius during exposure to high light intensity constitutes an adverse effect on its metabolism, since this species usually uses less than 25% of its total metabolic potential for standard metabolic demands.

Keywords:

• Cave animals
• light tolerance
• stygobite
• respiration
• ETS/R ratio
• Amphipoda
• Gammarus
• Niphargus

Acknowledgments

The authors acknowledge the financial support from the state budget by the Slovenian Research Agency (Research programme Communities, relations and communications in the ecosystems (P1-0255)). We would like to thank two anonymous reviewers for helpful comments on the manuscript and to Roger Pain for linguistic corrections of the text.