Benthic Monitoring

Crowe Valley Conservation Authority operates the benthic monitoring program within the watershed to assess and monitor water quality. In order to complete benthic monitoring, sample sites throughout the watershed are assessed based on basic water chemistry and benthic macroinvertebrate (benthos) community composition. This is achieved through the use of the Ontario Stream Assessment Protocol and Ontario Benthos Biomonitoring Network (OBBN).


What are benthic macroinvertebrates?

  • Small organisms lacking internal bone structures that live on, in, or near the bottom of water bodies

Why sample and study them?

  • They are a common and integral resident of aquatic ecosystems
  • They posses known tolerance ranges to organic & inorganic pollution
  • Their community composition varies with environmental conditions
  • They predictably respond to human and natural induced stressors
  • They aid in monitoring physical and chemical conditions through time
  • They provide a historical perspective missing in direct physical and chemical studies


Examples of Natural Induced Stressors to an Aquatic Environment:

  • Beavers
  • Create wetlands through flooding of the land-water interface (riparian zones)
  • Flooding
  • Changes the shape and flow of the waterbody
  • Changes nutrient cycling & decomposition rates
  • Reduced flow can increase the holding time of sediment and organic materials
  • Alters the overall habitat and therefore species composition of an aquatic environment

Examples of Human Induced Stressors to an Aquatic Environment:

  • Bioaccumlation & Biomagnification
  • Pollutants accumulating in fatty tissues of organisms over time
  • Species higher in the food web will experience increased pollution concentrations in their bodies due to larger consumption rates
  • Endocrine Disrupting Substances
  • Pollutants altering the growth, reproduction, and general development of exposed organisms
  • Climate Change
  • Changes in temperature can impact species’ ability to survive
  • Changes precipitation can alter water levels within a habitat



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