Sandification vs. muddification of tidal flats by benthic organisms: A flume study. (15th November 2019)

• Record Type: Journal Article
• Authors: Soissons, Laura M.; Gomes da Conceiçâo, Tatiana; Bastiaan, John; van Dalen, Jeroen; Ysebaert, Tom; Herman, Peter M.J.; Cozzoli, Francesco; Bouma, Tjeerd J.
• Is Part Of: Estuarine, coastal and shelf science. Volume 228(2019)
• Publication Date: 2019-11-15
• Subjects: Benthic organisms -- Cerastorderma edule -- Ruditapes philippinarum -- Suspended sediment concentration -- Sediment properties -- Silt content -- Tidal flats; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2019.106355
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: Bioturbating benthic organisms have typically been characterised by how they modify the vertical sediment erosion thresholds. By means of several annular flume experiments, we aimed to understand how benthic organisms may affect grain-size sediment properties over time, and how this depends on the sediment type and the sediment loading of the water column. We compared the effect of two bioturbating macroinvertebrate species: a local dominant species, the cockle Cerastoderma edule and a spreading non-indigeneous species, the clam Ruditapes philippinarum . Our results indicate that the effect of benthic organisms on sediment dynamics is strongly dependent on both the prevailing environmental conditions and the benthic species present. If sediment is sandy, the benthos can gradually enhance the silt content of the sediment by mixing in part of the daily tidal sediment deposition. In contrast, if sediment is muddy, benthos can gradually decrease the silt content of the sediment by specifically suspending the fine fraction. Moreover, we observed that the native cockles had a stronger impact than invasive clams. Therefore, bioturbating benthos can have an important effect in determining the local sediment properties, with the outcome depending both on the species in question and the environmental conditions the bioturbator lives in. Our findings show that sediment bioturbation may have strong implications for tidal flat stability undergoing major changes from natural or anthropogenic sources. Graphical abstract: Image 1 Highlights: Flumes are used to understand how benthic organisms modify sediment properties. Bioturbating benthic organisms have an effect on sediment dynamics and properties. This effect depends on the benthic species and local environmental conditions. If sediment is sandy, benthos enhance sediment silt content. If sediment is muddy, benthos decrease sediment silt content through resuspension.