Bioturbation and Biogeochemical Fluxes in Aquatic Sediments

Bioturbation—the physical disturbance and mixing of sediment by benthic organisms—plays a central role in controlling the exchange of particles and solutes at the sediment–water interface. Through activities such as burrowing, feeding and ventilation, macrofauna, meiofauna and microbial eukaryotes rework sediment particles (particulate fluxes) and pump overlying water into deeper layers (bioirrigation), enhancing oxygen penetration and driving microbially mediated pathways of carbon, nitrogen, phosphorus and metal cycling. These processes regulate the balance between aerobic and anaerobic respiration, shape the vertical distribution of redox zones and influence greenhouse-gas emissions. Bioturbation therefore underpins the capacity of lakes, estuaries and coastal seas to process organic matter, recycle nutrients, support primary productivity and contribute to global biogeochemical feedbacks. Understanding the mechanistic links between organism behavioural traits, community composition and sediment geochemistry is essential for predicting ecosystem responses to environmental change, including eutrophication, hypoxia and climate warming.

Research from Nature Portfolio

Exceptional fossil assemblages from Upper Jurassic shorelines have revealed that arenicolid polychaetes formed dense networks of fecal mounds nearly indistinguishable from those of living species, implying that sediment reworking and oxic microhabitat formation have been consistent drivers of benthic ecosystem engineering for over 150 million years. In laboratory mesocosms, non-biting midge larvae were shown to enhance lake-sediment respiration by up to 2.5-fold via bioirrigation, quantified using a novel bioreactive tracer sensitive solely to aerobic heterotroph activity. Experimental manipulations of invasive polychaetes demonstrated that species identity and density modulate the magnitude and direction of solute fluxes: some congeners enhanced nitrogen efflux strongly, while others predominantly influenced phosphate or silicate dynamics, emphasising the need to account for multispecies interactions in biogeochemical assessments.

Bioturbation and Biogeochemical Fluxes in Aquatic Sediments publication trend

The graph below shows the total number of articles in bioturbation and biogeochemical fluxes in aquatic sediments across all publications each year (not limited to Nature Index journals).

Technical terms

Bioturbation: The reworking of sediment particles by benthic organisms through burrowing, feeding and locomotion.

Bioirrigation: The advective transport of overlying water into sediment pore spaces induced by organismal ventilation or movement.

Benthic flux: The net exchange of particles or dissolved substances between the sediment and the overlying water column.

Redox profile: The vertical distribution of oxidising and reducing chemical conditions within sediment layers, influenced by biological and chemical processes.

Oxygen penetration depth: The maximum depth to which molecular oxygen diffuses or is advected into sediment, controlling aerobic microbial activity.

References

1. Jurassic paleosurfaces with fecal mounds reveal the last supper of arenicolid worms. Scientific Reports (2024).
2. Effects of bioirrigation of non-biting midges (Diptera: Chironomidae) on lake sediment respiration. Scientific Reports (2016).
3. Increasing densities of an invasive polychaete enhance bioturbation with variable effects on solute fluxes. Scientific Reports (2018).
4. Single-celled bioturbators: benthic foraminifera mediate oxygen penetration and prokaryotic diversity in intertidal sediment. Biogeosciences (2023).
5. Macrofaunal contributions to benthic nutrient fluxes revealed by radium disequilibrium. Limnology and Oceanography (2025).
6. Role of Macrofaunal Communities in the Vistula River Plume, the Baltic Sea—Bioturbation and Bioirrigation Potential. Biology (2023).