AB 16:137-147 (2012)  -  DOI: https://doi.org/10.3354/ab00447

Importance of waterborne cadmium and zinc accumulation in the suspension-feeding amphioxus Branchiostoma belcheri

Bin Lu1, Caihuan Ke1, Wen-Xiong Wang2,*

1State Key Laboratory for Marine Environmental Science, College of Oceanography and Environmental Science, Xiamen University, Xiamen 361005, PR China
2Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR
*Corresponding author. Email:

ABSTRACT: The amphioxus is often used as a model marine animal in biological research because of its special position in evolution. These animals have transparent surfaces and non-respiratory gills, and whether such specialization plays a role in the accumulation of metals remains unknown. In the present study, we determined the biokinetics of Cd and Zn in the amphioxus Branchiostoma belcheri, including metal assimilation efficiency (AE), the dissolved Cd and Zn uptake rate constants, and the efflux rate constant. Metal AEs were 7.6 to 34.3% for Cd and 8.4 to 42.9% for Zn in amphioxus feeding on 5 different algae, and the AEs of Zn were significantly influenced by the algal concentration. The dissolved uptake rate constants were 0.107 l g−1 d−1 for Cd and 0.061 l g−1 d−1 for Zn. The efflux rate constants were 0.012 to 0.033 d−1 for Cd and 0.031 to 0.040 d−1 for Zn following dietary or waterborne metal exposure. Overall, these determined biokinetics were comparable to those found in other suspension feeders, such as marine bivalves. However, amphioxus had a higher absorption efficiency from the dissolved phase than those found for marine bivalves, largely caused by the unique surface sorption of metals. Such unique surface uptake contributed to the dominance of waterborne Cd accumulation in amphioxus under most environmental conditions. For Zn, dietary exposure appeared to be more important than aqueous uptake due to its relatively high particle reactivity. The predicted trophic transfer factors of Cd and Zn were <1 under most conditions.

KEY WORDS: Amphioxus · Metals · Bioaccumulation · Exposure · Pathway

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Cite this article as: Lu B, Ke C, Wang WX (2012) Importance of waterborne cadmium and zinc accumulation in the suspension-feeding amphioxus Branchiostoma belcheri. Aquat Biol 16:137-147. https://doi.org/10.3354/ab00447

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