Jellyfish blooms are generally short lived, collapsing from food limitations, changes in water temperature or oxygen levels, or completing their life cycle. The death, sinking, and decomposition of jellyfish is rapid and leads to a mass release of dissolved and particulate, organic and inorganic matter in the water column or seafloor creating a significant source of food for the microbial community. Sinking and decomposition rates can vary for jellyfish depending on water temperature and depth. Some jellyfish decompose before reaching the seafloor, releasing organic matter into the water column. Others fall to the floor and then decompose, enriching the sediment with organic matter. In both scenarios the organic matter from the jellyfish is consumed by the bacterial community who simultaneously reduce available oxygen, at times contributing to hypoxia. In some cases, the jelly-falls are too large for consumption and organic matter accumulates on the seafloor creating a physical barrier for diffusion mechanisms, reducing oxygen transport into sediments. The result is an increase of ammonium in the surrounding water from bacterial remineralization and an increase of phosphate in the sediment from low oxygen redox reactions. However, when the decomposition creates low oxygen zones the ammonium cannot be utilized by primary production. Similarly, the low oxygen zones created by microbial respiration further shifts the consumption to the bacterial community (most macrofauna prefer oxygenated environments), again limiting the energy transfer to higher trophic levels.
