Environmental context and trophic trait plasticity in a key species, the tellinid clam Macoma balthica L.

Anna Törnroos, M. C. Nordström, K. Aarnio, E. Bonsdorff

Research output: Contribution to journalJournal articleResearchpeer-review


Species show varying levels of plasticity regarding morphology, physiology and behaviour in relation to their immediate environment, and several trait characteristics are habitat-dependent. Determining when and how the environmental context changes trait expression is of key importance for understanding the role of individual species for ecosystem functioning. The tellinid clam Macoma balthica can vary its feeding behaviour, shifting between deposit- and suspension-feeding. In order to study the context-dependency of this trophic plasticity in adult clams, we conducted an experiment assessing food uptake by using stable isotope signatures (delta C-13 and delta N-15). We transplanted individuals between and within two shallow bays differing in exposure (exposed sheltered) and sediment characteristics. Our results show that isotope signatures of clams differed between the two habitats and that clams in the exposed site showed stable isotope values linked to a diet of suspended particulate organic material, while values of individuals in the sheltered site corresponded to an uptake of sediment-bound organic material. Clams transplanted between these two environmental settings were gradually showing differing isotopic signatures from clams at their original habitat, over time mirroring the changes in clams in the site to which they were transferred. The shift in carbon and nitrogen stable isotopes of the clams provides insights into the context-dependent intraspecific feeding plasticity of this zoobenthic key species. The causes for this shift were coupled to contrasts in the hydrodynamic and biotic setting, implying that feeding plasticity may explain adaptation of organisms to changes in their surroundings. (C) 2015 Elsevier B.V. All rights reserved.
Original languageEnglish
JournalJournal of Experimental Marine Biology and Ecology
Pages (from-to)32-40
Publication statusPublished - 2015


  • species habitat
  • Mollusca Invertebrata Animalia (Animals, Invertebrates, Mollusks) - Pelecypoda [61500] Macoma balthica species clam common mature
  • carbon 15 isotope
  • carbon 7440-44-0
  • nitrogen 15 isotope
  • 00504, General biology - Taxonomy, nomenclature and terminology
  • 07508, Ecology: environmental biology - Animal
  • 07512, Ecology: environmental biology - Oceanography
  • 63526, Invertebrata: general and systematic - Mollusca
  • 64026, Invertebrata: comparative, experimental morphology, physiology and pathology - Mollusca
  • Ecology, Environmental Sciences
  • Marine Ecology
  • Systematics and Taxonomy

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