Data for Trace metals in natural lakes of different trophic state: Response of primary production to low concentrations of manganese, cobalt, nickel, copper and zinc

Trace metal micronutrients are known to play an important role in the optimal functioning of aquatic microorganisms involved in the sequestration of atmospheric carbon dioxide. Great effort has been dedicated towards understanding the controls and biogeochemical cycling of trace metal micronutrients in the global ocean over several decades. Conversely, the cycling of trace metals in lakes is not well established. This study investigated the biogeochemical cycling of five biologically important trace metals, namely manganese, cobalt, nickel, copper and zinc in three New Zealand lakes that extends our initial study focussed on iron biogeochemical behaviour. These study lakes not only have low concentrations of these trace metals, but also differ in their trophic state and water mass mixing regimes, enabling trace metal behaviour in each lake setting to be compared and contrasted. Modelling of the bioavailable fraction of each trace metal was used to estimate the fraction of the dissolved phase available for biological uptake. The cycling of the metals was driven by the different physicochemical and biogeochemical factors distinctive for each lake, including water column oxygen concentrations and the extent to which each metal was bound to particulates. Intriguingly, increased biological uptake during times of high phytoplankton growth was not observed for any of the investigated trace metals. The results from this study emphasise the important role biogeochemical cycling plays in regulating the distributions and bioavailability of trace metals in lakes.