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Sediment segregation by biodiffusing bivalves

Montserrat Trotsenburg, F. and Colen van, C. and Provoost, P. and Milla, M. and Ponti, M. and Van den Meersche, K. and Ysebaert, T. and Herman, P.M.J. (2009) Sediment segregation by biodiffusing bivalves. Estuarine Coastal and Shelf Science, 83, 379-391. ISSN 0272-7714.

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Official URL: http://dx.doi.org/10.1016/j.ecss.2009.04.010

Abstract

The selective processing of sediment fractions (sand and mud; > 63 μm and ≤ 63 μm median grain size) by macrofauna was assessed using two size classes of inert, UV-fluorescent sediment fraction tracers (luminophores). The luminophores were applied to the sediment surface in 16 m2 replicated plots, defaunated and control, and left to be reworked by infauna for 32 days. As the macrofaunal assemblage in the ambient sediment and the control plots was dominated by the common cockle Cerastoderma edule, this species was used in an additional mesocosm experiment. The diversity, abundance and biomass of the defaunated macrobenthic assemblage did not return to control values within the experimental period. Both erosion threshold and bed elevation increased in the defaunated plots as a response to the absence of macrofauna and an increase in microphytobenthos growth. In the absence of macrobenthos, we observed an accretion of 7 mm sediment, containing ca. 60% mud. Image analysis of the vertical distribution of the different luminophore size classes showed that the cockles preferentially mobilised fine material from the sediment, thereby rendering it less muddy and effectively increasing the sand: mud ratio. Luminophore profiles and budgets of the mesocosm experiment under “no waves-no current” conditions support the field data very well.

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:6341
Deposited On:23 Mar 2010 01:00
Last Modified:24 Apr 2012 16:44

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