The responses (survival, growth, and/or reproduction) of test organisms in six concentrations of toxicants in acute and chronic tests. Chemical and water quality parameters were measured for quality assurance and quality control purposes.

The responses (survival, growth, and/or reproduction) of test organisms in six concentrations of toxicants in acute and chronic tests. Chemical and water quality parameters were measured for quality assurance and quality control purposes.

Insect metamorphosis often results in substantial chemical changes that can fractionate isotopes and alter contaminant concentrations. We exposed larval mayflies (Baetis tricaudatus) to an aqueous zinc gradient (3-340 µg Zn/l) and measured the change in zinc tissue concentrations at different stages of metamorphosis. We also measured changes in stable isotopes (δ15N and δ13C) in unexposed B. tricaudatus. Zinc concentrations in larvae were positively related to aqueous zinc, increasing 9-fold across the exposure gradient. Zinc concentrations in adults were also positively related to aqueous concentrations, but were 7-fold lower than larvae. However, this relationship varied according to adult substage (subimago vs imago) and sex. Tissue concentrations in female imagoes were not related to exposure concentrations, but the converse was true for all other stage by sex combinations. Metamorphosis also altered isotopic ratios, increasing δ15N, but not δ13C. Thus, the main effects of metamorphosis on insect chemistry were large declines in zinc concentrations coupled with enriched δ15N signatures. For zinc, this change is largely consistent across the aqueous exposure gradient. However, the differences among sexes and stages suggest that caution is warranted when using isotopes or metal concentrations measured in one insect stage (e.g., larvae) to assess risk to wildlife that feed on subsequent life stages (e.g., adults).

Insect metamorphosis often results in substantial chemical changes that can fractionate isotopes and alter contaminant concentrations. We exposed larval mayflies (Baetis tricaudatus) to an aqueous zinc gradient (3-340 µg Zn/l) and measured the change in zinc tissue concentrations at different stages of metamorphosis. We also measured changes in stable isotopes (δ15N and δ13C) in unexposed B. tricaudatus. Zinc concentrations in larvae were positively related to aqueous zinc, increasing 9-fold across the exposure gradient. Zinc concentrations in adults were also positively related to aqueous concentrations, but were 7-fold lower than larvae. However, this relationship varied according to adult substage (subimago vs imago) and sex. Tissue concentrations in female imagoes were not related to exposure concentrations, but the converse was true for all other stage by sex combinations. Metamorphosis also altered isotopic ratios, increasing δ15N, but not δ13C. Thus, the main effects of metamorphosis on insect chemistry were large declines in zinc concentrations coupled with enriched δ15N signatures. For zinc, this change is largely consistent across the aqueous exposure gradient. However, the differences among sexes and stages suggest that caution is warranted when using isotopes or metal concentrations measured in one insect stage (e.g., larvae) to assess risk to wildlife that feed on subsequent life stages (e.g., adults).

This release is for data on Zinc concentrations and isotopic signatures of an aquatic insect (mayfly, Baetis tricaudatus). Mayflies were exposed to an aqueous zinc concentration gradient in a laboratory experiment. Zinc concentrations were measured in water, algae (mayfly food), and different mayfly lifestages. Natural abundances of carbon and nitrogen isotopes were also measured in different life stages. This data set includes on Zinc data. Isotope data are provided in a separate file. The abstract for a journal article explaining the results of the experiment follows below: Insect metamorphosis often results in substantial chemical changes that can fractionate isotopes and alter contaminant concentrations. We exposed larval mayflies (Baetis tricaudatus) to an aqueous zinc gradient (3-340 µg Zn/l) and measured the change in zinc tissue concentrations at different stages of metamorphosis. We also measured changes in stable isotopes (δ15N and δ13C) in unexposed B. tricaudatus. Zinc concentrations in larvae were positively related to aqueous zinc, increasing 9-fold across the exposure gradient. Zinc concentrations in adults were also positively related to aqueous concentrations, but were 7-fold lower than larvae. However, this relationship varied according to adult substage (subimago vs imago) and sex. Tissue concentrations in female imagoes were not related to exposure concentrations, but the converse was true for all other stage by sex combinations. Metamorphosis also altered isotopic ratios, increasing δ15N, but not δ13C. Thus, the main effects of metamorphosis on insect chemistry were large declines in zinc concentrations coupled with enriched δ15N signatures. For zinc, this change is largely consistent across the aqueous exposure gradient. However, the differences among sexes and stages suggest that caution is warranted when using isotopes or metal concentrations measured in one insect stage (e.g., larvae) to assess risk to wildlife that feed on subsequent life stages (e.g., adults).

This release is for data on Zinc concentrations and isotopic signatures of an aquatic insect (mayfly, Baetis tricaudatus). Mayflies were exposed to an aqueous zinc concentration gradient in a laboratory experiment. Zinc concentrations were measured in water, algae (mayfly food), and different mayfly lifestages. Natural abundances of carbon and nitrogen isotopes were also measured in different life stages. This data set includes on Zinc data. Isotope data are provided in a separate file. The abstract for a journal article explaining the results of the experiment follows below: Insect metamorphosis often results in substantial chemical changes that can fractionate isotopes and alter contaminant concentrations. We exposed larval mayflies (Baetis tricaudatus) to an aqueous zinc gradient (3-340 µg Zn/l) and measured the change in zinc tissue concentrations at different stages of metamorphosis. We also measured changes in stable isotopes (δ15N and δ13C) in unexposed B. tricaudatus. Zinc concentrations in larvae were positively related to aqueous zinc, increasing 9-fold across the exposure gradient. Zinc concentrations in adults were also positively related to aqueous concentrations, but were 7-fold lower than larvae. However, this relationship varied according to adult substage (subimago vs imago) and sex. Tissue concentrations in female imagoes were not related to exposure concentrations, but the converse was true for all other stage by sex combinations. Metamorphosis also altered isotopic ratios, increasing δ15N, but not δ13C. Thus, the main effects of metamorphosis on insect chemistry were large declines in zinc concentrations coupled with enriched δ15N signatures. For zinc, this change is largely consistent across the aqueous exposure gradient. However, the differences among sexes and stages suggest that caution is warranted when using isotopes or metal concentrations measured in one insect stage (e.g., larvae) to assess risk to wildlife that feed on subsequent life stages (e.g., adults).

Survival, growth and reproduction of Ceriodaphnia dubia and Neocloeon triangulifer, metal concentrations and water quality parameters from nickel and zinc exposures in natural waters

This dataset is from the third of four experiments which test the toxicity of several metals with aquatic insect communities that were colonized in the field and then transferred and tested in experimental streams. Here we report original data from testing the toxicity of copper (Cu), nickel (Ni), and zinc (Zn), singly and in mixtures, to natural aquatic insect communities. Methods are the same as those in Experiment 2, with the addition of in situ, in-vivo fluorescence measurements of benthic algae. Trays of cleaned gravel were placed in a stream (the Cache La Poudre River, Colorado) and allowed to colonize for about 40 days before being translocated to Aquatic Experimental Stream Laboratory (AXL) which was located at the USGS Fort Collins Science Center. There the insects were exposed for 30 days to metal mixtures in ratios and concentrations similar to those occurring in ambient conditions. Emerging adult insects were captured and collected daily throughout the experiment, while larvae and metal residues were measured in periphyton and Brachycentrus caddisflies (a common, large-bodied, robust insect that could survive high metals accumulations) at the end of the experiment. In addition, algal biomass was measured in situ by in-vivo fluorescence at the end of the experiment.

This dataset is from the third of four experiments which test the toxicity of several metals with aquatic insect communities that were colonized in the field and then transferred and tested in experimental streams. Here we report original data from testing the toxicity of copper (Cu), nickel (Ni), and zinc (Zn), singly and in mixtures, to natural aquatic insect communities. Methods are the same as those in Experiment 2, with the addition of in situ, in-vivo fluorescence measurements of benthic algae. Trays of cleaned gravel were placed in a stream (the Cache La Poudre River, Colorado) and allowed to colonize for about 40 days before being translocated to Aquatic Experimental Stream Laboratory (AXL) which was located at the USGS Fort Collins Science Center. There the insects were exposed for 30 days to metal mixtures in ratios and concentrations similar to those occurring in ambient conditions. Emerging adult insects were captured and collected daily throughout the experiment, while larvae and metal residues were measured in periphyton and Brachycentrus caddisflies (a common, large-bodied, robust insect that could survive high metals accumulations) at the end of the experiment. In addition, algal biomass was measured in situ by in-vivo fluorescence at the end of the experiment.