Mercury contamination of macroinvertebrates from grassland ponds with and without fish

Background/Question/Methods

The purpose of this study was to examine mercury (Hg) in macroinvertebrate communities from grassland ponds with and without fish communities.  We sampled macroinvertebrates from five ponds with fish and five ponds without fish, at the LBJ National Grassland in north Texas, USA.  

Results/Conclusions

Ponds without fish contained a higher biomass of macroinvertebrates and taxa with higher concentrations of Hg, which led to a greater pool of Hg in the macroinvertebrate community of fishless ponds.  Seventy-three percent of the macroinvertebrate biomass from ponds without fish was composed of taxa capable of emerging and these taxa have the potential to transport Hg out of ponds into terrestrial food webs.