A numerical model is proposed for investigatingthe potential of calcium carbonatedissolution in copepod guts. A sensitivityanalysis is performed to reveal criticalparameters. Gut clearance rate is dependent ontemperature and grazing rate and determines thetime scale on which ingested calcite is subjectto dissolution. Highest dissolution isobtained when the individual zooplankton isalternating between grazing and non-grazing and feedingis restricted to the night-time period. Model resultsshow that up to 70% of the ingested carbonate may bedissolved in the guts, considering reingestion of faecalpellets in the absence of a phytoplanktonbloom, while approximately15% dissolution is to be expectedin a bloom situation. An estimate is made for the contributionof calcite dissolution in copepod guts to the proposed globalcalcite loss in the water column.