A comparative experimental approach to ecotoxicology in shallow-water and deep-sea holothurians suggests similar behavioural responses.

Brown, Alastair, Wright, Roseanna, Mevenkamp, Lisa and Hauton, Chris (2017) A comparative experimental approach to ecotoxicology in shallow-water and deep-sea holothurians suggests similar behavioural responses. Aquatic Toxicology, 191 . pp. 10-16. DOI 10.1016/j.aquatox.2017.06.028.

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Supplementary data:

Abstract

Highlights:
• Shallow-water and deep-sea holothurians avoided copper-contaminated sediment.
• Shallow-water taxa may be suitable ecotoxicological proxies for deep-sea taxa.
• Avoidance behaviour may have bioenergetic consequences.

Abstract:
Exploration of deep-sea mineral resources is burgeoning, raising concerns regarding ecotoxicological impacts on deep-sea fauna. Assessing toxicity in deep-sea species is technologically challenging, which promotes interest in establishing shallow-water ecotoxicological proxy species. However, the effects of temperature and hydrostatic pressure on toxicity, and how adaptation to deep-sea environmental conditions might moderate these effects, are unknown. To address these uncertainties we assessed behavioural and physiological (antioxidant enzyme activity) responses to exposure to copper-spiked artificial sediments in a laboratory experiment using a shallow-water holothurian (Holothuria forskali), and in an in situ experiment using a deep-sea holothurian (Amperima sp.). Both species demonstrated sustained avoidance behaviour, evading contact with contaminated artificial sediment. However, A. sp. demonstrated sustained avoidance of 5 mg l−1 copper-contaminated artificial sediment whereas H. forskali demonstrated only temporary avoidance of 5 mg l−1 copper-contaminated artificial sediment, suggesting that H. forskali may be more tolerant of metal exposure over 96 h. Nonetheless, the acute behavioural response appears consistent between the shallow-water species and the deep-sea species, suggesting that H. forskali may be a suitable ecotoxicological proxy for A. sp. in acute (≤24 h) exposures, which may be representative of deep-sea mining impacts. No antioxidant response was observed in either species, which was interpreted to be the consequence of avoiding copper exposure. Although these data suggest that shallow-water taxa may be suitable ecotoxicological proxies for deep-sea taxa, differences in methodological and analytical approaches, and in sex and reproductive stage of experimental subjects, require caution in assessing the suitability of H. forskali as an ecotoxicological proxy for A. sp. Nonetheless, avoidance behaviour may have bioenergetic consequences that affect growth and/or reproductive output, potentially impacting fecundity and/or offspring fitness, and thus influencing source-sink dynamics and persistence of wider deep-sea populations.

Document Type: Article
Keywords: Bathymetric; Deep-sea mining; Ecology; Hydrostatic pressure; Physiology; Temperature; Toxicology
Refereed: Yes
Open Access Journal?: No
Publisher: Elsevier
Projects: JPIO-MiningImpact
Expeditions/Models/Experiments:
Date Deposited: 20 Mar 2018 14:01
Last Modified: 17 Dec 2018 08:19
URI: https://oceanrep.geomar.de/id/eprint/42304

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