MEPS 422:179-191 (2011)  -  DOI: https://doi.org/10.3354/meps08910

Contrasting macrobenthic activities differentially affect nematode density and diversity in a shallow subtidal marine sediment

Ulrike Braeckman1,*, Carl Van Colen1, Karline Soetaert2, Magda Vincx1, Jan Vanaverbeke1

1Department of Biology, Marine Biology Section, Ghent University, Krijgslaan 281/S8, 9000 Ghent, Belgium
2Netherlands Institute of Ecology (NIOO-KNAW), Centre for Estuarine and Marine Ecology, PO Box 140, 4400 AC Yerseke, The Netherlands

ABSTRACT: By bioturbating and bio-irrigating the sea floor, macrobenthic organisms transport organic matter and oxygen from the surface to deeper layers, thereby extending the habitat suitable for smaller infauna. Next to these engineering activities, competition, disturbance and predation may also affect the spatial distribution of these smaller organisms. In a controlled laboratory experiment, we studied the effects of 3 functionally different macrobenthic species on the vertical distribution of nematodes. Abra alba, a suspension-deposit feeding bivalve reworking the sediment randomly, Lanice conchilega, a suspension-deposit feeding, tube-irrigating polychaete and Nephtys hombergii, a burrowing predatory polychaete, were added in single-species treatments to sediment from a coastal subtidal station in the Belgian part of the North Sea, sieved (1 mm) to remove macrofauna. After 14 d, the control treatment without macrobenthos was found to be detrimental to nematode density and diversity, which points to the importance of macrobenthic engineering to sustain the smaller components of the food web. Nematode densities were highest at the sediment surface in all treatments, but subsurface density peaks were observed in A. alba (to 3 cm depth) and L. conchilega (to 7 cm depth) microcosms. In the A. alba treatment, the dominant non-selective deposit feeders and the epistrate feeders shifted downwards probably to avoid disturbance and exploitative competition by the bivalve siphons at the surface, while they might have benefited from the faecal pellets deposited in the subsurface. In the L. conchilega treatment, the several dominant species were redistributed over depth layers, indicating polychaete-mediated habitat extension from surface into depth. Nematode communities seemed hardly affected by the presence of N. hombergii. These results reveal that functionally contrasting macrobenthic engineering effects shape nematode communities in different ways, which may maintain the role of nematodes in ecosystem functioning. The present study therefore highlights the need for conservation of macrobenthic functional diversity.


KEY WORDS: Bioturbation · Macrobenthos · Ecosystem engineering · Nematodes · Vertical distribution · Diversity · Density


Full text in pdf format
Supplementary material 
Cite this article as: Braeckman U, Van Colen C, Soetaert K, Vincx M, Vanaverbeke J (2011) Contrasting macrobenthic activities differentially affect nematode density and diversity in a shallow subtidal marine sediment. Mar Ecol Prog Ser 422:179-191. https://doi.org/10.3354/meps08910

Export citation
Mail this link - Contents Mailing Lists - RSS
- -