The Heterogeneity of the Contents of Trace Metals in the Dominant Copepod Species in the Seawater Around Northern Taiwan

THE HETEROGENEITY OF THE CONTENTS OF TRACE METALS IN THE DOMINANT COPEPOD SPECIES IN THE SEAWATER AROUND NORTHERN TAIWAN

SHIH-HUI HSIAO1,4), JIANG-SHIOU HWANG1) and TIEN-HSI FANG2,3) 1) Institute of Marine Biology, National Taiwan Ocean University, Keelung 202, Taiwan, R.O.C. 2) Department of Marine Environmental Informatics, National Taiwan Ocean University, Keelung 202, Taiwan, R.O.C.

ABSTRACT The dominant copepod species, Canthocalanus pauper (Giesbrecht, 1888), Oncaea venusta Philippi, 1843, Temora turbinata (Dana, 1849), and Undinula vulgaris (Dana, 1849), collected from the sea around northern Taiwan and from the southern East China Sea extending to the Okinawa Trough, were analysed for trace metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) to study possible spatial heterogeneity in these species of copepods. Trace metal concentrations ranged as follows: Cd, 0.39-141.78 μg/g; Co, 0.03-91.9 μg/g; Cr, 2.26-243.5 μg/g; Cu, 4.36-195.5 μg/g; Fe, 19.96-2886.9 μg/g; Mn, 5.34-735.8 μg/g; Ni, 1.69-954.9 μg/g; Pb, 0.04-85.8 μg/g; and Zn, 5.57-941.8 μg/g. The average concentration of trace metals in the copepod samples analysed follows the sequence: Fe > Zn > Ni > Mn > Cu > Cr > Cd > Co > Pb. The sequence of total metal contents in the copepods is: Oncaea venusta > Temora turbinata > Canthocalanus pauper > Undinula vulgaris. The content of the same metal shows considerable variation both intra- and inter-speciﬁcally, and the difference in concentration can vary 1 to 3 orders of magnitude. We also found that metal concentrations in males are higher than in females in Oncaea venusta and Undinula vulgaris. In addition, copepod metal quota also display spatial variation: coastal water > southern East China Sea > Kuroshio Water, suggesting that the metal contents of copepods are inﬂuenced by the water quality of their marine environment.

RÉSUMÉ Les espèces dominantes de copépodes, Canthocalanus pauper (Giesbrecht, 1888), Oncaea venusta Philippi, 1843, Temora turbinata (Dana, 1849), et Undinula vulgaris (Dana, 1849), collec- tées de la mer autour du nord de Taiwan et au sud-est de la mer de Chine jusqu’a la fosse Océanique d’Okinawa ont été analysées pour les métaux traces (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, et Zn) aﬁn d’étudier une possible hétérogénéité spatiale chez ces espèces de copépodes. Les concentrations

3) Corresponding author; Fax: +886.24627674; e-mail: [email protected] 4) Present address: Department of Science Education, National Taipei University of Education, Taipei 106, Taiwan, R.O.C. © Koninklijke Brill NV, Leiden, 2010 Crustaceana 83 (2): 179-194 Also available online: www.brill.nl/cr DOI:10.1163/001121609X12511103974493 180 SHIH-HUI HSIAO, JIANG-SHIOU HWANG & TIEN-HSI FANG de ces métaux présentent les valeurs suivantes: Cd, 0,39-141,78 μg/g; Co, 0,03-91,9 μg/g; Cr, 2,26- 243,5 μg/g; Cu, 4,36-195,5 μg/g; Fe, 19,96-2886,9 μg/g; Mn, 5,34-735,8 μg/g; Ni, 1,69-954,9 μg/g; Pb, 0,04-85,8 μg/g; et Zn, 5,57-941,8 μg/g. La concentration moyenne de ces métaux dans les échan- tillons de copépodes analysés suit la séquence: Fe > Zn > Ni > Mn > Cu > Cr > Cd > Co > Pb. La séquence du contenu total en métaux dans les copépodes est: Oncaea venusta > Temora turbinata > Canthocalanus pauper > Undinula vulgaris. La quantité d’un même métal montre des variations intra- et inter-spéciﬁques considérables, et la différence en concentration peut varier entre 1 et 3 d’ordre d’amplitude. Nous avons aussi trouvé que les concentrations en métal chez les mâles sont plus élevées que chez les femelles chez Oncaea venusta et Undinula vulgaris.Deplus, les quotas de métaux par copépode montrent des variations spatiales: eau côtière > sud-est de la mer de Chine > eaux de Kuroshio, suggérant que le contenu en métal des copépodes est inﬂuencé par la qualité de l’eau de leur environnement marin.

INTRODUCTION

The species together constituting the zooplankton are the most numerous primary consumers and are widely distributed throughout the ocean. Many studies have indicated that free-living marine copepods have a great capacity to accumu- late trace metals (Zauke et al., 1996; Ritterhoff & Zauke, 1997; Kahle & Zauke, 2003; Fang et al., 2006; Hsiao et al., 2006; Zauke & Schmalenbach, 2006). The bio-concentration factor of marine copepods for trace metals generally ranges from 3 to 6 orders of magnitude (Kahle & Zauke, 2002, 2003; Fang et al., 2006; Hsiao et al., 2006). Many studies have shown that chemical pollutants may affect copepods to various degrees, ranging from sub-lethal to lethal effects, and thus have an impact on copepod population dynamics (Lindley et al., 1998; Hook & Fisher, 2001; Saunders & Moore, 2004). Trace metal accumulation in marine consumers is of great interest to marine scientists concerned with the fate and effects of conta- minants. Thus, understanding the accumulation of trace metals in the primary consumers, the zooplankton, is essential to establish a relevant trophic level scenario. Such knowledge has been widely established in the temperate and polar regions, like the North Sea, the Greenland Sea, the Weddell Sea, and the Barents Sea by Zauke and his coworkers in the last two decades (Zauke et al., 1996; Ritterhoff & Zauke, 1997; Kahle & Zauke, 2002, 2003; Zauke & Schmalenbach, 2006). These results frequently ﬁnd different species of zooplankton with greatly varying metal concentrations in the same body of ocean water. Zauke & Schmalenbach (2006) particularly indicated that there existed a substantial spatial heterogeneity of Cd content in the decapod crustacean, Pandalus borealis Kr¿yer, 1838 in the Barents Sea and attributed this phenomenon to the Cd-anomaly. They also suggested that probably no global background values of metal contents in zooplankton can be de- ﬁned. Instead, regional background values should be established to follow possible future trends of metals in bio-monitors (Zauke & Schmalenbach, 2006).