Benthic Marine Monitoring

Vibrant coral reef at War in the Pacific National Historical Park.
Vibrant coral reef at War in the Pacific National Historical Park.

NPS Photo/K.L. Kramer

Description and Rationale

Four parks within the Pacific Island Network (PACN) contain rich benthic (sea floor) marine communities that are home to algae, corals, and other invertebrates. Coral reefs often form the structural framework of nearshore underwater ecosystems and are compared to tropical rainforests in terms of species diversity and the complexity of interactions.

Corals are excellent indicators of the overall health of tropical reef environments because of their sensitivity to environmental degradation. Primary stressors to coral reefs include diseases, sedimentation, eutrophication, alien species, fishing, storms, and global climate change. The United Nations Environment Programme considers coral reefs a worldwide indicator ecosystem for global climate change.

Monitoring Objectives

  1. Determine long-term trends in the abundance (density of individuals or percent cover) of sessile marine macroinvertebrate (e.g., corals, sponges) and macroalgal assemblages at fixed and random sites between 10 and 20 meters depth.
  2. Determine trends in benthic small scale topography at randomly selected, fixed stations stratified by habitat or reef zone.
  3. Determine trends in recruitment rate of hard corals (as an assemblage) to uniform artificial surfaces at selected sites on the fore reef between 10 and 20 meters depth.
  4. Determine trends in rate of growth and survival of randomly selected coral colonies of a common, trans-Pacific species (e.g., Pocillopora damicornis, Pocillopora verrucosa, Porites lobata) growing at similar depth.
  5. Determine long-term trends in the incidence and severity of coral and algal disease and bleaching.
For more information on PACN I&M benthic marine monitoring contact: Sheila McKenna

Monitored At

Last updated: December 21, 2023

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