The Effect of Tubificid Bioturbation on Vertical Water Exchange across the Sediment–Water Interface

Abstract

The bioturbation activity of macroinvertebrates can affect the level of water exchange across the sediment–water interface. The impact of tubificid worm with different densities on the vertical water exchange at the sediment–water interface was investigated based on laboratory flume experiments. Vertical water fluxes, as well as physiochemical parameters, were measured at seven-day intervals, and the maximum penetration depths were obtained by dye injection before and after the tubificid bioturbation experiment, respectively. The bioturbation effects can be summarized in two aspects: (1) when the density was less than (or equal to) 20 individual/10 cm2, the volume of vertical water exchange positively correlated with the tubificid bioturbation. Once the density exceeded (or equaled) 25 individual/10 cm2, the vertical water flux decreased with increasing tubificid bioturbation. After 14 to 21 days, a negative correlation was identified between the bioturbation and the vertical water flux under all biological densities. (2) The maximum depth that the surface water can penetrate the sediment increased with increasing tubificid density. These results revealed that the vertical water was closely related to the biological density. The study has certain reference significance to understanding the spatiotemporal heterogeneity of hyporheic water exchange on a local scale.

Micro‐computed tomography scanning approaches to quantify, parameterize and visualize bioturbation activity in clogged streambeds: A proof of concept

“…Such findings are consistent with what is expected of L. variegatus , an upward conveyor bioturbator type that feeds head down (McCall & Fisher, 1980; Mermillod‐Blondin & Rosenberg, 2006; Nogaro et al, 2006). The ratio volume/area occupied by galleries was extensive and provided the basis to assume a potential increase in sediment permeability via increased porosity, which is particularly important to help offset the effects of streambed clogging (Mao et al, 2020). Roche et al, 2016 showed that the burrows were biased to the top 0.01 m of the bed, leaving large areas of the subsurface unaltered, with very rare activity in the deeper sections of the core.…”

Environmental context mediates the interaction between fine sediment and hyporheic macroinvertebrate

“…In addition to exploring the ecological habitat of the Wei River, we also tried to investigate the close relationship between bioturbation and the external environment (e.g., hydrological variables, fine sediment, etc.). For example, is the macroinvertebrate bioturbation more intense in the clogged environment as in the artificial simulations (Mao et al, 2020)? Specific objectives of the paper are to (i) describe the assemblage characteristics of hyporheic macroinvertebrates across the Weihe River and assess the variations associated with fine sediments and seasons, (ii) examine the variability of bioturbation and its close relationship with environmental variables, and (iii) explain the interaction between macroinvertebrates and fine-sediment clogging.…”

Advances in Environmental Hydraulics

“…Four studies approached the stream and river systems from a variety of perspectives, ranging from the physical modelling of flow with vegetation [13] and the numerical simulation of solute transport in river with dead zones [14], to the laboratory study of flood discharge atomisation [15] and the geomorphic characterisation and classification of a large river [16]. Three contributions are about hyporheic fluxes: two field studies investigated these fluxes at a small river confluence [17] and the effects of such fluxes on the macroinvertebrate community [18], while their relationship with the bioturbation activity of macroinvertebrates was studied in laboratory [19]. The last two articles addressed the accuracy of groundwater flux measurement using a seepage meter in the laboratory [20] and the experimental validation of the Darcy-Buckingham (DB) law in unsaturated porous rocks [21].…”

“…At the same time, the bioturbation activity of macroinvertebrates can affect the water exchange across the sediment-water interface (SWI) in the hyporheic zone. Mao et al [19] studied the impact of tubificid worms as a dominant group of benthic macroinvertebrates on the vertical water exchange across the sediment-water interface through laboratory flume experiments. The results showed that tubificid bioturbation affected the vertical water flux and penetration depth across the SWI, and such effects had pronounced correlation with both density and duration of bioturbation.…”