The absorption and loss of radioactive and non-radioactive manganese by the lobster,Homarus vulgaris

Abstract

Inactive Mn concentrations have been measured in lobster tissues. In the internal tissues of fresh animals, muscle contains 0.5–1.1 μg/g wet tissue, hepatopancreas contains 4.1–5.7 μg/g, excretory organs contain 2–5.5 μg/g and the blood contains 1.4–3.8 μg/g. Gill Mn concentrations are very variable and up to 30 μg/g are found. About 98 % of the Mn in the body lies in the calcified exoskeleton. Concentrations in the carapace are variable and are of the order of 100–300 μg/g of wet tissue. Possible ways in which the body Mn content may be controlled have been studied.Manganese is lost from the blood during starvation and is absorbed so slowly from solution in sea water that normally an appreciable amount of the body Mn must be absorbed from food. Absorption from the stomach takes place via the hepatopancreas and the amount absorbed appears to be proportional to the Mn concentration of the stomach fluid. Similarly, there is no evidence that the slow absorption of Mn from solution in sea water across the gills can in any way be controlled and it may be a passive rather than an active process.