Abstract: Patterns of the distribution of rare earth elements (REEs) in natural objects are important geochemical indicators of the state of the environment. Data on the REE contents in fucus algae from different horizons of the littoral of the Barents Sea are presented for the first time. The behavior of REEs in natural processes is controlled by the solubility of their compounds, their capability of complex formation, and the tetrad-effect of fractionation. Natural factors determining REE migration in the sediment–water–macrophytes system are discussed.