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Marine Ecology Progress Series

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MEPS 203:191-203 (2000)  -  doi:10.3354/meps203191

Effects of chronic fluoranthene exposure on sibling species of Capitella with different development modes

Inez Linke-Gamenick1,*, Valery E. Forbes1, Nuria Méndez2

1Department of Life Sciences and Chemistry, Roskilde University, PO Box 260, 4000 Roskilde, Denmark
2Laboratorio de Invertebrados Bentónicos, Estación Mazatlán, Instituto de Ciencias del Mar y Limnología, UNAM, Apartado Postal 811, Mazatlán, 82000 Sinaloa, Mexico

ABSTRACT: Toxic effects of the polycyclic aromatic hydrocarbon fluoranthene (FLU) on life-history traits and their demographic consequences were investigated in 3 non-interbreeding Capitella sibling species with different physiological tolerances and developmental modes: sensitive Capitella sp. S from oxygen-rich intertidal sediments of the North Sea (Germany); tolerant Capitella sp. M from sediments near shallow hydrothermal vents off Milos (Greece), a habitat low in organic matter with steep abiotic gradients and high sulfide concentrations; tolerant Capitella sp. I from New York (USA), known to dominate eutrophicated/polluted environments. Both Capitella spp. M and I can develop into hermaphrodites and have lecithotrophic larval development. In contrast, Capitella sp. S appears to be dioecious and has direct development with benthic juveniles. In life-table-response experiments (LTRE), juveniles from the 3 species were raised under different FLU concentrations (0 to 95 µg g-1 FLU), and data on age-specific survival, growth and life-history parameters were recorded at weekly intervals. Under control conditions, the 3 Capitella species differed markedly in a number of life-history traits and population growth rates (λ), with Capitella sp. S showing the lowest λ (1.05), and Capitella sp. M the highest (1.42). Chronic exposure to inreasing FLU concentrations also revealed species-specific differences in individual- and population-level toxic responses. Highest FLU concentrations (95 µg g-1) markedly reduced juvenile survival and completely inhibited reproduction in Capitella sp. S, whereas individual life-history traits in Capitella spp. M and I were affected little, if at all. At the population level, the highest FLU exposures resulted in λ values of effectively zero in Capitella sp. S, whereas λ of Capitella spp. M and I remained >1. In conclusion, the combination of opportunistic life-history features, reproductive flexibility, and physiological adaptations enables Capitella spp. M and I to colonize habitats rapidly after local disturbance and to persist in stressed and unpredictable environments; whereas in Capitella sp. S, population extinction under toxicant stress mainly results from its physiological sensitivity.

KEY WORDS: Capitella sibling species complex · Fluoranthene · Life-history traits · Benthic and lecithotrophic development · Population growth rate

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