Data from: The production of ‘food boluses’ by Antarctic krill and implications for organic matter transport

Antarctic krill (Euphausia superba) are a key species in the marine
Antarctic ecosystem. Food boluses, a byproduct of feeding where krill form
a compact food mass within their feeding basket, were formed and rejected
under laboratory conditions. We explored the mechanism used to form these
boluses by examining krill feeding behaviour and observed two distinct
scenarios that can lead to the formation of boluses: 1) when
concentrations of food items are too high for krill to filter feed
efficiently; 2) when either biological or foreign particles are caught in
the feeding basket and unable to be processed by the krill. We measured
the frequency of rejection of the boluses, along with their composition,
sinking rates, and carbon and nitrogen contents. For cell concentrations
over 108 cells L-1, the frequency of rejection ranged from 2.6 to 17
boluses per hour. Bolus sinking velocities averaged 367 m d-1, with carbon
and nitrogen contents averaging 24.1 µg C mm-3 and 2.3 µg N mm-3,
respectively. Our findings suggest krill may display this behaviour in
situ, and, if so, this behaviour may also occur in other krill species
with similar feeding behaviour.