Jellyfish Decomposition Studies at IRIS.

Sediment cores collected in Hardangerfjord were used to examine the ammonium, sulphide and oxygen levels produced by decomposing jellyfish.  This information is needed to understand the dynamics of scavengers feeding on jellyfalls.  For example, it is reasonably to hypothesise that scavengers are discouraged from feeding on jellyfalls if high levels of ammonium and sulphides are produced, and oxygen is reduced during decomposition.

Jellyfish carcasses were added to sediment cores to simulate a jellyfall.

The size of jellyfalls is also hypothesised to affect the levels of ammonium and sulphide produced therefore relatively small, medium and large amounts of jelly fish material were added to the cores.

Cores were sampled periodically over 36 hours to examine changes in ammonium, sulphides and oxygen.  This information will be used to interpolate results from the scavenger deployment studies conducted in June 2016 and 2017.