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Effects of Contaminants on Linked Aquatic and Terrestrial Food Webs

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By Fort Collins Science Center July 5, 2016

Most aquatic insects live in fresh water as larvae and move to land as flying adults to complete their life cycle. Although often ignored, the emergence of adults can transfer the effects of contamination from aquatic to terrestrial ecosystems as the adults are eaten by predators such as spiders, birds, and bats.

Our scientists are investigating how contaminants move from streams, rivers, and lakes into riparian zones and how contamination alters the ecological linkages between these systems. We use large-scale field studies in various aquatic ecosystems, ranging from mountain headwater streams to the Great Lakes, and conduct complementary experiments at the new aquatic experimental laboratory at the Fort Collins Science Center. The mesocosm facility in our state-of-the-art laboratory is designed to replicate the coupled aquatic-riparian ecosystems. Results from these studies are helping managers to better evaluate water-quality criteria, to design and implement restoration plans for contaminated aquatic systems, and to assess the effectiveness of remedial actions.

Below are other science projects associated with this project.

link
Scientists work on insect traps in the Prairie Pothole region of North Dakota.

Aquatic Ecology and Contaminants

The Aquatic Ecology and Contaminants Team investigates critical ecological processes operating in aquatic and riparian ecosystems and how these processes are affected by human activities. We address questions through a combination of field studies, laboratory experiments, and modeling, while working at multiple levels of biological organization from cells through ecosystems. Topics include land...
By
Land Management Research Program, Fort Collins Science Center
link

Aquatic Ecology and Contaminants

The Aquatic Ecology and Contaminants Team investigates critical ecological processes operating in aquatic and riparian ecosystems and how these processes are affected by human activities. We address questions through a combination of field studies, laboratory experiments, and modeling, while working at multiple levels of biological organization from cells through ecosystems. Topics include land...
Learn More

Below are publications associated with this project.

Riparian spiders as sentinels of polychlorinated biphenyl contamination across heterogeneous aquatic ecosystems

Riparian spiders are being used increasingly to track spatial patterns of contaminants in and fluxing from aquatic ecosystems.However, our understanding of the circumstances under which spiders are effective sentinels of aquatic pollution is limited. The present study tests the hypothesis that riparian spiders may be effectively used to track spatial patterns of sediment pollution by polychlorinate
Authors
Johanna M. Kraus, Polly P. Gibson, David M. Walters, Marc A. Mills
By
Ecosystems Mission Area, Fort Collins Science Center

Aquatic pollution increases use of terrestrial prey subsidies by stream fish

Stream food webs are connected with their riparian zones through cross-ecosystem movements of energy and nutrients. The use and impact of terrestrial subsidies on aquatic consumers is determined in part by in situ biomass of aquatic prey. Thus, stressors such as aquatic pollutants that greatly reduce aquatic secondary production could increase the need for and reliance of stream consumers on terr
Authors
Johanna M. Kraus, Justin F. Pomeranz, Andrew S. Todd, David M. Walters, Travis S. Schmidt, Richard B. Wanty
By
Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Fort Collins Science Center, Geology, Geophysics, and Geochemistry Science Center

Metamorphosis alters contaminants and chemical tracers in insects: implications for food webs

Insects are integral to most freshwater and terrestrial food webs, but due to their accumulation of environmental pollutants they are also contaminant vectors that threaten reproduction, development, and survival of consumers. Metamorphosis from larvae to adult can cause large chemical changes in insects, altering contaminant concentrations and fractionation of chemical tracers used to establish c
Authors
Johanna M. Kraus, David M. Walters, Jeff S. Wesner, Craig A. Stricker, Travis S. Schmidt, Robert E. Zuellig
By
Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Colorado Water Science Center, Fort Collins Science Center

Metamorphosis enhances the effects of metal exposure on the mayfly, Centroptilum triangulifer

The response of larval aquatic insects to stressors such as metals is used to assess the ecological condition of streams worldwide. However, nearly all larval insects metamorphose from aquatic larvae to winged adults, and recent surveys indicate that adults may be a more sensitive indicator of stream metal toxicity than larvae. One hypothesis to explain this pattern is that insects exposed to elev
Authors
Jeff S. Wesner, Johanna M. Kraus, Travis S. Schmidt, David M. Walters, William H. Clements
By
Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Colorado Water Science Center, Fort Collins Science Center

Emergence flux declines disproportionately to larval density along a stream metals gradient

Effects of contaminants on adult aquatic insect emergence are less well understood than effects on insect larvae. We compared responses of larval density and adult emergence along a metal contamination gradient. Nonlinear threshold responses were generally observed for larvae and emergers. Larval densities decreased significantly at low metal concentrations but precipitously at concentrations of m
Authors
Travis S. Schmidt, Johanna M. Kraus, David M. Walters, Richard B. Wanty
By
Water Resources Mission Area, Colorado Water Science Center, Geology, Geophysics, and Geochemistry Science Center

Transfer of trace metals from streams to terrestrial food webs by emerging aquatic insects in mineralized alpine ecosystems

No abstract available.
Authors
Johanna M. Kraus, R. B. Wanty, Travis S. Schmidt, David M. Walters, Craig A. Stricker

Variation in active and passive resource inputs to experimental pools: mechanisms and possible consequences for food webs

1. Cross-ecosystem movements of resources, including detritus, nutrients and living prey, can strongly influence food web dynamics in recipient habitats. Variation in resource inputs is thought to be driven by factors external to the recipient habitat (e.g. donor habitat productivity and boundary conditions). However, inputs of or by ‘active’ living resources may be strongly influenced by recipien
Authors
Johanna M. Kraus, Leanna T. Pletcher, James R. Vonesh

Diet shift of lentic dragonfly larvae in response to reduced terrestrial prey subsidies

Inputs of terrestrial plant detritus and nutrients play an important role in aquatic food webs, but the importance of terrestrial prey inputs in determining aquatic predator distribution and abundance has been appreciated only recently. I examined the numerical, biomass, and diet responses of a common predator, dragonfly larvae, to experimental reduction of terrestrial arthropod input into ponds.
Authors
Johanna M. Kraus

Below are partners associated with this project.

Bureau of Reclamation

National Park Service (NPS)

State Fish and Wildlife Agencies

U.S. Environmental Protection Agency (EPA)

U.S. Forest Service (USFS)

Most aquatic insects live in fresh water as larvae and move to land as flying adults to complete their life cycle. Although often ignored, the emergence of adults can transfer the effects of contamination from aquatic to terrestrial ecosystems as the adults are eaten by predators such as spiders, birds, and bats.

Our scientists are investigating how contaminants move from streams, rivers, and lakes into riparian zones and how contamination alters the ecological linkages between these systems. We use large-scale field studies in various aquatic ecosystems, ranging from mountain headwater streams to the Great Lakes, and conduct complementary experiments at the new aquatic experimental laboratory at the Fort Collins Science Center. The mesocosm facility in our state-of-the-art laboratory is designed to replicate the coupled aquatic-riparian ecosystems. Results from these studies are helping managers to better evaluate water-quality criteria, to design and implement restoration plans for contaminated aquatic systems, and to assess the effectiveness of remedial actions.

Below are other science projects associated with this project.

link
Scientists work on insect traps in the Prairie Pothole region of North Dakota.

Aquatic Ecology and Contaminants

The Aquatic Ecology and Contaminants Team investigates critical ecological processes operating in aquatic and riparian ecosystems and how these processes are affected by human activities. We address questions through a combination of field studies, laboratory experiments, and modeling, while working at multiple levels of biological organization from cells through ecosystems. Topics include land...
By
Land Management Research Program, Fort Collins Science Center
link

Aquatic Ecology and Contaminants

The Aquatic Ecology and Contaminants Team investigates critical ecological processes operating in aquatic and riparian ecosystems and how these processes are affected by human activities. We address questions through a combination of field studies, laboratory experiments, and modeling, while working at multiple levels of biological organization from cells through ecosystems. Topics include land...
Learn More

Below are publications associated with this project.

Riparian spiders as sentinels of polychlorinated biphenyl contamination across heterogeneous aquatic ecosystems

Riparian spiders are being used increasingly to track spatial patterns of contaminants in and fluxing from aquatic ecosystems.However, our understanding of the circumstances under which spiders are effective sentinels of aquatic pollution is limited. The present study tests the hypothesis that riparian spiders may be effectively used to track spatial patterns of sediment pollution by polychlorinate
Authors
Johanna M. Kraus, Polly P. Gibson, David M. Walters, Marc A. Mills
By
Ecosystems Mission Area, Fort Collins Science Center

Aquatic pollution increases use of terrestrial prey subsidies by stream fish

Stream food webs are connected with their riparian zones through cross-ecosystem movements of energy and nutrients. The use and impact of terrestrial subsidies on aquatic consumers is determined in part by in situ biomass of aquatic prey. Thus, stressors such as aquatic pollutants that greatly reduce aquatic secondary production could increase the need for and reliance of stream consumers on terr
Authors
Johanna M. Kraus, Justin F. Pomeranz, Andrew S. Todd, David M. Walters, Travis S. Schmidt, Richard B. Wanty
By
Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Fort Collins Science Center, Geology, Geophysics, and Geochemistry Science Center

Metamorphosis alters contaminants and chemical tracers in insects: implications for food webs

Insects are integral to most freshwater and terrestrial food webs, but due to their accumulation of environmental pollutants they are also contaminant vectors that threaten reproduction, development, and survival of consumers. Metamorphosis from larvae to adult can cause large chemical changes in insects, altering contaminant concentrations and fractionation of chemical tracers used to establish c
Authors
Johanna M. Kraus, David M. Walters, Jeff S. Wesner, Craig A. Stricker, Travis S. Schmidt, Robert E. Zuellig
By
Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Colorado Water Science Center, Fort Collins Science Center

Metamorphosis enhances the effects of metal exposure on the mayfly, Centroptilum triangulifer

The response of larval aquatic insects to stressors such as metals is used to assess the ecological condition of streams worldwide. However, nearly all larval insects metamorphose from aquatic larvae to winged adults, and recent surveys indicate that adults may be a more sensitive indicator of stream metal toxicity than larvae. One hypothesis to explain this pattern is that insects exposed to elev
Authors
Jeff S. Wesner, Johanna M. Kraus, Travis S. Schmidt, David M. Walters, William H. Clements
By
Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Colorado Water Science Center, Fort Collins Science Center

Emergence flux declines disproportionately to larval density along a stream metals gradient

Effects of contaminants on adult aquatic insect emergence are less well understood than effects on insect larvae. We compared responses of larval density and adult emergence along a metal contamination gradient. Nonlinear threshold responses were generally observed for larvae and emergers. Larval densities decreased significantly at low metal concentrations but precipitously at concentrations of m
Authors
Travis S. Schmidt, Johanna M. Kraus, David M. Walters, Richard B. Wanty
By
Water Resources Mission Area, Colorado Water Science Center, Geology, Geophysics, and Geochemistry Science Center

Transfer of trace metals from streams to terrestrial food webs by emerging aquatic insects in mineralized alpine ecosystems

No abstract available.
Authors
Johanna M. Kraus, R. B. Wanty, Travis S. Schmidt, David M. Walters, Craig A. Stricker

Variation in active and passive resource inputs to experimental pools: mechanisms and possible consequences for food webs

1. Cross-ecosystem movements of resources, including detritus, nutrients and living prey, can strongly influence food web dynamics in recipient habitats. Variation in resource inputs is thought to be driven by factors external to the recipient habitat (e.g. donor habitat productivity and boundary conditions). However, inputs of or by ‘active’ living resources may be strongly influenced by recipien
Authors
Johanna M. Kraus, Leanna T. Pletcher, James R. Vonesh

Diet shift of lentic dragonfly larvae in response to reduced terrestrial prey subsidies

Inputs of terrestrial plant detritus and nutrients play an important role in aquatic food webs, but the importance of terrestrial prey inputs in determining aquatic predator distribution and abundance has been appreciated only recently. I examined the numerical, biomass, and diet responses of a common predator, dragonfly larvae, to experimental reduction of terrestrial arthropod input into ponds.
Authors
Johanna M. Kraus

Below are partners associated with this project.

Bureau of Reclamation

National Park Service (NPS)

State Fish and Wildlife Agencies

U.S. Environmental Protection Agency (EPA)

U.S. Forest Service (USFS)

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