What are Stressors & Receptors?

Stressors and receptors are necessary to understand when navigating Tethys because a large part of the organizational structure revolves around this interaction. When you search through the Knowledge Base, you will be able to narrow down search results by clicking on specific stressors or receptors in the facet boxes to the right. Identifying these interactions is important for addressing concerns about environmental effects. But let's first get a good understanding of what this means:

Baseball Example The analogy we will use is a bat and baseball, as a stressor and receptor respectively. The ball is quickly moving in a direction after a pitch, until another player swings a bat that causes the ball, to reverse direction and speed up. The ball is considered the receptor as the object that is being changed, while the bat is considered the stressor as the object causing the change. In fact, there might be multiple stressors that cause the direction and speed of the ball to change, such as wind or speed.

Whale Strike Example Now a Tethys example that might be useful is searching for documents on what might happen if a whale were to collide with a rotating tidal turbine blade. While you might immediately want to classify the turbine as the stressor, we take it further and assign device characteristics such as noise or electromagnetic fields as the stressors. In this case, the moving components of the turbine are the stressor and the whale is the receptor for the collision that might be injured. Therefore selecting 'Dynamic Device' and 'Marine Mammals' will find documents related to this interaction.

Photos of a Baseball Bat and a Humpback Whale

List of Stressors

  • Chemicals - An acute spill or chronic release of chemicals over time.
  • Dynamic Device - Any part of the device that moves.
  • EMF - An electromagnetic field created by undersea cables.
  • Energy Removal - Changes in water could remove energy from the system.
  • Lighting - Light added for navigational purposes may attract or disorient organisms.
  • Noise - Sounds created during construction and operation of device.
  • Static Device - Any part of the device that does not move significantly.

List of Receptors

  • Bats - Certain bat species have been known to migrate great distances offshore, at risk of collision with the device.
  • Benthic Invertebrates - A broad term that encompasses cephalopods (squid, octopus), crustaceans (crabs, shrimp), molluscs (clams, barnacles), and various other benthic organisms.
  • Birds - Generic term that applies to all types of birds.
    • Ground-Nesting Birds - Birds that nest and reside mostly on the ground, including quail, pheasants, and prairie chickens.
    • Passerines - The most common type of bird, known for perching.
    • Raptors - Birds of prey that hunt and feed on small animals.
    • Seabirds - Seabirds are birds that have adapted to life within the marine environment.
    • Shorebirds - Shorebirds are birds commonly found along sandy or rocky shorelines, mudflats, and shallow waters.
    • Waterfowl - Birds with webbed feet for quatic environments, including ducks, geese, and swans.
  • Ecosystem - The balance within a community of organisms and their environment (food chain).
  • Fish - Resident fish living near the device and migratory fish passing through the area.
  • Marine Mammals - A broad term that encompasses pinnipeds (seals, sea lions), cetaceans (dolphins and whales) and sea otters.
  • Sea Turtles - Sea turtles commonly utilize sea currents and travel great distances.
  • Farfield Environment - The large-scale effects of a device beyond those affecting the direct site.
  • Nearfield Habitat - The physical environment surrounding a device.
  • Terrestrial Mammals - A broad term that encompasses carnivores (wolves, bears) and ungulates (deer, moose).
    • Socio-economics - The effects on the local society and economy.
      • Aesthetics - Altering the existing landscape or seascape.
      • Climate Change - How renewable energy affects climate change caused by anthropogenic activities.
        Environmental Impact Assessment - The process of examining the anticipated environmental effects of a proposed project or development.
      • Fishing - Commercial fishing is an established industry in the marine environment.
      • Legal and Policy - How governing bodies handle renewable energy projects through policy and legal frameworks.
      • Life Cycle Assessment - Environmental Assessment through all stages of a project.
      • Marine Spatial Planning - A science-based tool that seeks to plan and manage sea uses in a way that helps achieve sustainable development of marine areas.
      • Navigation - Vessels moving in proximity to a renewable energy project.
      • Recreation - People enjoying activities in proximity to a renewable energy project.
      • Stakeholder Engagement - People and companies with an interest in a renewable energy project.

    Many documents discuss more than one stressor-receptor interaction, so they will be tagged accordingly.