MEPS 376:21-32 (2009)  -  DOI: https://doi.org/10.3354/meps07788

Habitat modification mediated by motile surface stirrers versus semi-motile burrowers: potential for a positive feedback mechanism in a eutrophied ecosystem

Satu Viitasalo-Frösén1,2,*, Ari O. Laine1,3, Maiju Lehtiniemi1,2

1Finnish Institute of Marine Research, PO Box 2, 00561 Helsinki, Finland
2Present address: Marine Centre, Finnish Environment Institute, PO Box 140, 00251 Helsinki, Finland
3Present address: Metsähallitus, Natural Heritage Services, Saponkatu 2, 48100 Kotka, Finland

ABSTRACT: We performed a 4 wk laboratory experiment with the semi-motile burrowers Macoma balthica and Marenzelleria spp. and the motile surface sediment stirrers Monoporeia affinis and Mysis mixta to study their effects on the transport of tracer particles (mean diameter [∅] 1 µm) in the sediment, sediment parameters (depth of the oxidized layer, water content, organic matter content), water turbidity, and nutrient fluxes across the sediment-water interface (PO43–, NO2 + NO3, NH4+; measured weekly). Two densities were included for each taxon, representing a low and a high field density. M. balthica significantly increased particle mixing, the rates being 59.6 and 61.9 × 10–3 cm2 d–1. While all taxa increased turbidity in the overlying water, the strongest effects were caused by M. affinis and M. mixta, resulting in 112- and 45-fold increases, respectively. In addition, these 2 motile species increased oxidation of the sediment surface layers. A distinctive difference in the nutrient fluxes was observed between the semi-motile (M. balthica, Marenzelleria spp.) and the motile taxa (M. affinis, M. mixta). The former increased the efflux of both PO43– and NH4+, while the latter suppressed the efflux of NH4+ and decreased the sediment uptake of NOx, indicating enhanced N removal. Higher nutrient exchange rates were observed at the higher animal densities. We conclude that a shift in the benthic communities from the 2 motile to the 2 semi-motile taxa, observed throughout the northern Baltic Sea, may notably alter the regime of benthic nutrient cycling and thereby the performance of the entire ecosystem.


KEY WORDS: Bioturbation · Motile · Semi-motile · Nutrient cycling · Particle mixing · Turbidity


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Cite this article as: Viitasalo-Frösén S, Laine AO, Lehtiniemi M (2009) Habitat modification mediated by motile surface stirrers versus semi-motile burrowers: potential for a positive feedback mechanism in a eutrophied ecosystem. Mar Ecol Prog Ser 376:21-32. https://doi.org/10.3354/meps07788

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