Macroalgae fuels coastal soft-sediment macrofauna: A triple-isotope approach across spatial scales

T.I. Kahma, A.M.L. Karlson, X. Sun, C.-M. Mörth, C. Humborg, A. Norkko, I.F. Rodil

Research output: Contribution to journalArticleScientificpeer-review


Shallow coastal zones may provide cross-habitat nutrient subsidies for benthic communities offshore, as macrophyte matter can drift to deeper sediments. To study the relative importance of carbon and nutrient flows derived from different primary food sources in a coastal ecosystem, the diets of clam Macoma balthica, polychaete Marenzelleria spp. and mussel Mytilus trossulus were examined across environmental gradients in the northern Baltic Sea using a triple-isotope approach (i.e. 13C, 15N and 34S) and Bayesian mixing models (MixSIAR). Our results suggest that in shallow habitats, production from Fucus vesiculosus is the primary energy source for M. balthica. The proportion of macroalgae-derived matter in the diet of M. balthica and Marenzelleria spp. decreased following a depth gradient. Our models for M. trossulus indicate that the pelagic POM dominates its diet. Our results indicate a trophic connectivity between shallow macrophyte-dominated and deeper habitats, which receive significant amounts of nutrient subsidies from shallower areas.
Original languageEnglish
JournalMarine Environmental Research
Publication statusAccepted/In press - 5 Oct 2020
MoE publication typeA1 Journal article-refereed

Fields of Science

  • Coastal ecosystem
  • Benthic macrofauna
  • Food sources
  • Stable isotopes
  • Spatial scale
  • Macroalgae
  • 1181 Ecology, evolutionary biology

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