S. D. Roast & J. Widdows & M. B. Jones (2002): Distribution and swimming behaviour of Neomysis integer (Peracarida: Mysidacea) in response to gradients of dissolved oxygen following exposure to cadmium at environmental concentrations MARINE ECOLOGY PROGRE
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S. D. ROAST & J. WIDDOWS & M. B. JONES
2002
Distribution and swimming behaviour of Neomysis integer (Peracarida: Mysidacea) in response to gradients of dissolved oxygen following exposure to cadmium at environmental concentrations
MARINE ECOLOGY PROGRESS SERIES Vol. 237: 185–194
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NeMys doc_id: 10061
Available for editors
ABSTRACT: Neomysis integer (Peracarida: Mysidacea) is a dominant member of the hyperbenthos of
the upper reaches of European estuaries. They are highly dynamic environments that experience,
amongst other things, large-scale fluctuations in dissolved oxygen (DO) concentration. The present
study reports the tolerance and swimming responses of N. integer to hypoxia, together with the modifying
effects of environmentally realistic cadmium concentrations (0 to 1.0 µg Cd2+ l–1). The tolerance
(ET50, or time taken for 50% of mysids to show an effect) of N. integer to hypoxia was ca. 5 min at 20%
saturation (59.4 µmolO2 l–1); however, a 7 d pre-exposure to 0.5 µgCd2+ l–1 reduced the ET50 to
ca. 3 min. Mysids did not avoid areas of severe hypoxia (<10% saturation) and made excursions of
short duration (ca. 30 s) into such areas. Following cadmium exposure, however, mysids did avoid
areas of hypoxia. When challenged with a current velocity of 6 cm s–1 (normal for their natural habitat),
mysids showed positive rheotaxic behaviour, but as DO concentration was progressively
decreased, fewer mysids swam forward into the current and more maintained position. Fewer
cadmium-exposed mysids showed positive rheotaxis than control mysids, and decreasing DO concentration
had no significant effect on the proportion of mysids exhibiting this behaviour. The results
are discussed in terms of how DO concentrations might affect mysid distributions in the natural
environment and how cadmium exposure might disrupt these responses.
KEY WORDS: Estuarine mysids · Hypoxia · Behaviour · Cadmium
