Science Inventory

Comparison of coral reef communities in proximity to ocean effluent pipes off the north coast of Puerto Rico


Santavy, D., C. Horstmann, E. Huertas, AND S. Raimondo. Comparison of coral reef communities in proximity to ocean effluent pipes off the north coast of Puerto Rico. ENVIRONMENTAL MONITORING AND ASSESSMENT. Springer, New York, NY, 195:162, (2023).


Land-based sources of pollution are significant drivers of coral reef decline. Degradation of the biological condition of coral reef biota in the US Caribbean region has been attributed to sewage effluent exposure from wastewater treatment plants (WWTPs). EPA has been developing biocriteria for coral reefs through collaborative efforts of ORD, Office of Water, and Region 2. This project evaluated potential long-term effects of effluent discharge on coral reefs in marine waters adjacent to WWTPs outfalls obtained from monitoring programs conducted by Puerto Rico Aquaduct Authority. The four WWTPs studied were located along the north and northwestern Shore of Puerto Rico. Our analysis of these data did not detect long-term impact on spatial benthic coverage of the coral reef communities associated with location respective of WWTP effluent pipe. Our analyses were limited by the design of the survey, which was initiated in 1999, several decades after the WWTP became active and any immediate impacts of the outflow likely occurred before the study began. The low number of coral monitoring stations resulted in low spatial representation of the survey sites. Temporal changes in coral coverage were most significant around a widespread bleaching event that occurred in 2005 and impacted all of the study sites. Since the analyses were limited by the survey design, we offer recommendations to improve the design to better evaluate changes to coral coverage on the northern coast of Puerto Rico. 


<section lang="en" style="box-sizing: inherit; color: #333333; font-family: Georgia, Palatino, serif; font-size: 18px; background-color: #fcfcfc;" aria-labelledby="Abs1" data-title="Abstract " data-gtm-vis-first-on-screen-50443292_562="2111" data-gtm-vis-total-visible-time-50443292_562="10000" data-gtm-vis-first-on-screen-50443292_563="2111" data-gtm-vis-total-visible-time-50443292_563="10000" data-gtm-vis-has-fired-50443292_562="1" data-gtm-vis-has-fired-50443292_563="1"> Coral reefs are declining globally as a result of multiple stressors, including land-based stressors, such as sedimentation and pollution, and those that are related to a changing climate, such as increases in ocean acidification. Degradation of US Caribbean coral reef biota has been associated with exposure to sewage effluent from wastewater treatment plants (WWTPs). The Puerto Rico Aqueduct and Sewer Authority (PRASA) maintains WWTPs on the north coast of Puerto Rico, which release effluent into the marine environment in the vicinity of coral reefs. Using data collected by PRASA surveys conducted from 1999 to 2013, we examined coral reef condition at survey sites to identify potential changes or differences in reefs with respect to their proximity to the WWTP effluent pipes (e.g., upstream, downstream). The proportion of coverage represented by all coral, sensitive taxa, and tolerant taxa were compared across sites located upstream and downstream of WWTP effluent pipes using multivariate approaches and analysis of variance. The proportion of healthy, sensitive coral species and invasive or tolerant coral species were not different at sites downstream of the WWTP effluent pipe compared to upstream. These results are caveated by the limited sampling design, highly variable communities across WWTP locations, and the sparsity or absence of well-developed coral reef communities at most stations. We evaluate the strengths and weaknesses of the survey design and provide recommendations for future coral reef surveys investigating potential impacts of WWTP effluent.

Record Details:

Product Published Date:01/01/2023
Record Last Revised:02/24/2023
OMB Category:Other
Record ID: 357172