Alteration of physico-chemical and microbial properties in freshwater substrates by burrowing invertebrates

Abstract

a b s t r a c tThe hyporheic interstitial provides habitat for many different organisms -from bacteria to burrowing invertebrates. Due to their burrowing and sediment reworking behaviour, these ecosystem engineers have the potential to affect hyporheic processes such as respiration and nutrient cycling. However, there is a lack of studies that characterize the interactions between bioturbators, physico-chemical habitat properties and microbial communities in freshwater substrates. In a standardized laboratory experiment, we investigated the effects of three functionally different bioturbators, duck mussels (Anodonta anatina, Linnaeus 1758), mayfly nymphs (Ephemera danica, Müller 1764) and tubificid worms (Tubifex tubifex, Müller 1774), on the physico-chemical conditions and bacterial communities in hyporheic substrates. We hypothesized that different invertebrates distinctly alter habitat conditions and thus microbial community composition, depending on the depth and the manner of burrowing. A. anatina and E. danica caused an increase in interstitial oxygen concentration, whereas strong declines in oxygen concentration and redox potential were detected in the T. tubifex treatment. These effects on physico-chemical habitat properties were even detectable in open water. Mussels and tubificid worms also significantly influenced the composition of bacterial communities in the hyporheic zone. A loss or replacement of bioturbators in stream ecosystems due to anthropogenic habitat alterations is expected to result in shifts in microbial community compositions, with effects on nutrient fluxes, pollutant degradation and benthic food webs. An understanding of the effects of functionally different native and invasive bioturbators is crucial to predict changes in stream ecosystem functioning.

Habitat recovery and restoration in aquatic ecosystems: current progress and future challenges

“…Refuges from predation can also be increased for herbivorous zooplankton to help reduce phytoplankton blooms (Moss, ; Vakkilainen et al, ). In stream ecosystems, bioturbators such as lampreys, mussels or burrowing insect larvae can strongly affect microbial community composition, nutrient fluxes and food web effects (Boeker et al, ; Boeker and Geist, ), therefore qualifying as target species for restoration. In enclosed marine systems, suspension‐feeding species can be introduced or boosted to manage water quality by enhancing bio‐filtration should a clear water state be desired (Allen et al, ).…”

Interactions between Unionida and non‐native species: A global meta‐analysis

“…Although unionid mussels occur in most freshwater habitats, the highest diversity and biomass are found within medium to large rivers, typically in dense multispecies beds that contribute the majority of benthic invertebrate biomass (Strayer et al, ). When occurring in high abundances, freshwater mussels can have important ecosystem functions, sometimes acting as ecosystem engineers (Boeker, Lueders, Mueller, Pander, & Geist, ; Vaughn, ). As unionid mussels are relatively long lived (most lifespans range between 15 and 40 years in North America (Haag, ) and nearly 200 years for the European freshwater pearl mussel Margaritifera margaritifera (Linnaeus, 1758) (Bauer, )), and as some function as ecological indicator (Atkinson, Christian, Spooner, & Vaughn, ), umbrella, and flagship species, they are important targets for aquatic conservation efforts (Geist, , ).…”

Extent and Causes of Siltation in a Headwater Stream Bed: Catchment Soil Erosion is Less Important than Internal Stream Processes

“…The stream bed provides an important key habitat for many aquatic species that either permanently or temporarily depend on its physicochemical properties (Findlay, 1995;Kemp et al, 2011;Boeker et al, 2016). For instance, the reproduction success of many riverine fishes such as the economically important salmonids depends on the availability of coarse substrates and high oxygen supply during egg incubation (Acornley & Sear, 1999;Sternecker & Geist, 2010;.…”