An assessment of nutrients and sedimentation in the St. Thomas East End Reserves, US Virgin Islands

  • Anthony S. Pait
  • Francis R. GaldoJr
  • S. Ian Hartwell
  • Dennis A. Apeti
  • Andrew L. Mason


Nutrients and sedimentation were monitored for approximately 2 years at six sites in the St. Thomas East End Reserves (STEER), St. Thomas, USVI, as part of a NOAA project to develop an integrated environmental assessment. Concentrations of ammonium (NH4+) and dissolved inorganic nitrogen (DIN) were higher in Mangrove Lagoon and Benner Bay in the western portion of STEER than in the other sites further east (i.e., Cowpet Bay, Rotto Cay, St. James, and Little St. James). There was no correlation between rainfall and nutrient concentrations. Using a set of suggested nutrient thresholds that have been developed to indicate the potential for the overgrowth of algae on reefs, approximately 60% of the samples collected in STEER were above the threshold for orthophosphate (HPO4=), while 55% of samples were above the DIN threshold. Benner Bay had the highest sedimentation rate of any site monitored in STEER, including Mangrove Lagoon. There was also an east to west and a north to south gradient in sedimentation, indicative of higher sedimentation rates in the western, more populated areas surrounding STEER, and sites closer to the shore of the main island of St. Thomas. Although none of the sites had a mean or average sedimentation rate above a suggested sedimentation threshold, the mean sedimentation rate in Benner Bay was just below the threshold.


St. Thomas US Virgin Islands Nutrients Sedimentation STEER 



Funding for this work was provided by NOAA’s Coral Reef Conservation Program. We would also like to thank Jean-Pierre Oriol, Director of the Division of Coastal Zone Management of the USVI Department of Planning and Natural Resources (DPNR), Anita Nibbs of DPNR Division of Environmental Protection, Tyler Smith, Sandra Romano, and Renata Platenberg of the University of the Virgin Islands (UVI), and Rob Ferguson and Marlon Hibbert of NOAA’s CRCP, for the help with the planning, logistics, and interpretation of results.


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Copyright information

© This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply 2018

Authors and Affiliations

  • Anthony S. Pait
    • 1
  • Francis R. GaldoJr
    • 2
  • S. Ian Hartwell
    • 1
  • Dennis A. Apeti
    • 1
  • Andrew L. Mason
    • 1
  1. 1.NOAA/NOS/National Centers for Coastal Ocean ScienceSilver SpringUSA
  2. 2.The University of the Virgin Islands, 2 John Brewers Bay, St ThomasCharlotte AmalieUSA

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