Rare earth elements (REE) are essential in many new technologies. While anthropogenic dispersion of REE into the environment are expected in the future, their biogeochemical fate and interactions at biological interfaces are still largely unexplored. Due to their chemical nature (generally trivalent and hard metals), REE can potentially compete among themselves or with other ubiquitous trivalent metals for uptake sites at the surface of aquatic organisms. In the current study, the bioavailability and uptake of gadolinium (Gd) was assessed in the green alga, Chlamydomonas reinhardtii, while in the presence of various trivalent elements (Al, Eu, Fe, Nd, Tm, and Y). In the absence of competitors, Gd uptake was well described by a Michaelis–Menten equation with an affinity constant (K_Gd) of 10^7.1 and a maximum internalization flux (J_max) of 1.95 ± 0.09 × 10⁻² amol µm⁻² min⁻¹. Neither Al(III) nor Fe(III) had notable effects on Gd uptake in the conditions tested; however, Gd uptake was reduced with increasing concentrations of other REE. These had binding constants with uptake sites very similar to that of Gd (K_{Nd, Y, Tm, Eu} = 10^7.0). Our results suggest that the different REE likely share common transport sites and that the biotic ligand model (BLM) can be used to predict their uptake.

稀土元素 (REE) 在许多新技术中必不可少。虽然预计未来 REE 会因人为扩散到环境中，但它们的生物地球化学归宿和生物界面的相互作用在很大程度上仍未得到探索。由于其化学性质（通常是三价和硬金属），REE 可能会相互竞争或与其他普遍存在的三价金属竞争水生生物表面的吸收位点。在当前的研究中，在存在各种三价元素（Al、Eu、Fe、Nd、Tm 和 Y）的情况下，评估了绿藻莱茵衣藻中钆 (Gd) 的生物利用度和摄取量。在没有竞争者的情况下，Gd 的吸收可以通过具有亲和力常数 (K _Gd) 为 10 ^7.1和最大内化通量 (J _max ) 为 1.95 ± 0.09 × 10 ^-2  amol µm ^-2  min ^-1。在测试条件下，Al(III) 和 Fe(III) 均未对 Gd 吸收产生显着影响；然而，随着其他 REE 浓度的增加，Gd 的吸收减少。它们具有与 Gd 非常相似的吸收位点的结合常数 (K _{Nd, Y, Tm, Eu}  = 10 ^7.0 )。我们的结果表明，不同的 REE 可能共享共同的转运位点，并且生物配体模型 (BLM) 可用于预测它们的吸收。