Myriophyllum spicatum Pumps Essential and Nonessential Trace Elements from Sediments to Epiphytes

Abstract

To test the hypothesis that elements can be transferred from freshwater sediments to macrophytes and to epiphytes, we grew Myriophyllum spicatum in natural sediments containing 60Co and 54Mn (essential) and 137Cs, 152Eu, 154Eu, and 155Eu (nonessential). We found no differences between shoot or epiphyte to sediment bioaccumulation factors (BAFs) and only found differences between root and shoot to sediment BAFs for 60Co and 54Mn, probably because these elements adsorb onto root surfaces. We found no differences in BAFs for any elements between shoots and epiphytes, suggesting no differences in the transfer of essential and nonessential elements. There were, however, interelement differences for the roots, again probably due to surface adsorption related to redox sensitivity. Using isotope specific activity ratios, we calculated that over 75% of the Co and 100% of the Mn in M. spicatum was obtained from the sediments and that all Co and Mn in the epiphytes was sediment derived through the host. Although the net flux of trace elements from the sediments to the water via macrophytes has been shown to be small in most situations, buried pulses of nonessential elements may be reintroduced to the littoral food web by epiphytes being grazed by invertebrates and fish.