Bioirrigation

Bioirrigation refers to the process of benthic organisms flushing their burrows with overlying water. The exchange of dissolved substances between the porewater and overlying seawater that results is an important process in the context of the biogeochemistry of the oceans. Marine coastal ecosystems often have organisms that destabilize sediment. They change the physical state of the sediment. Thus improving the conditions for other organisms and themselves. These organisms often also cause bioturbation, which is commonly used interchangeably or in reference with bioirrigation. Bioirrigation works as two different processes. These processes are known as particle reworking and ventilation, which is the work of benthic macro-invertebrates (usually ones that burrow). This particle reworking and ventilation is caused by the organisms when they feed (faunal feeding), defecate, burrow, and respire. Bioirrigation is responsible for a large amount of oxidative transport and has a large impact on biogeochemical cycles. Bioirrigation is a main component in element cycling. Some of these elements include: Magnesium, Nitrogen, Calcium, Strontium, Molybdenum, and Uranium. Other elements are only displaced at certain steps in the bioirrigation process. Aluminium, Iron, Cobalt, Copper, Zinc, and Cerium are all affected at the start of the process, when the larvae begins to dig into the sediment. While Manganese, Nickel, Arsenic, Cadmium and Caesium were all mobilized slightly after the burrowing process. When trying to describe this biologically driven dynamic process, scientists have not been able to develop a 3D image of the process yet. There is a hybrid medical imaging technique using a position emission tomography/computed tomography (PET/CT) to measure the ventilation and visualize the pore water advection that is caused by the organisms in 4D imaging. When coastal ecosystems do not have bioirrigating organisms, like lugworms, it results in a lot of sedimentary problems.