首页 | 本学科首页   官方微博 | 高级检索  
     


Septic systems contribute to nutrient pollution and harmful algal blooms in the St. Lucie Estuary,Southeast Florida,USA
Affiliation:1. Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland;2. Centre for Polar Studies, Leading National Research Centre, Będzińska 60, 41-200 Sosnowiec, Poland;3. Institute of Geological Sciences, Jagiellonian University, Oleandry 2A, 30-063 Kraków, Poland;1. Marine Science Department, University of Hawai‘i at Hilo, 200 W. Kawili St., Hilo, HI 96720, USA;2. Tropical Conservation Biology and Environmental Science Graduate Program, University of Hawai‘i at Hilo, 200 W. Kawili St., Hilo, HI 96720, USA
Abstract:Nutrient enrichment is a significant global-scale driver of change in coastal waters, contributing to an array of problems in coastal ecosystems. The St. Lucie Estuary (SLE) in southeast Florida has received national attention as a result of its poor water quality (elevated nutrient concentrations and fecal bacteria counts), recurring toxic Microcystis aeruginosa blooms, and its proximity to the northern boundary of tropical coral species in the United States. The SLE has an artificially large watershed comprised of a network of drainage canals, one of which (C-44) is used to lower the water level in Lake Okeechobee. Public attention has primarily been directed at nutrient inputs originating from the lake, but recent concern over the importance of local watershed impacts prompted a one-year watershed study designed to investigate the interactions between on-site sewage treatment and disposal systems (OSTDS or septic systems), groundwaters, and surface waters in the SLE and nearshore reefs. Results provided multiple lines of evidence of OSTDS contamination of the SLE and its watershed: 1) dissolved nutrients in groundwaters and surface waters were most concentrated adjacent to two older (pre-1978) residential communities and the primary canals, and 2) sucralose was present in groundwater at residential sites (up to 32.0 μg/L) and adjacent surface waters (up to 5.5 μg/L), and 3) δ15N values in surface water (+7.5 o/oo), macroalgae (+4.4 o/oo) and phytoplankton (+5.0 o/oo) were within the published range (>+3 o/oo) for sewage N and similar to values in OSTDS-contaminated groundwaters. Measured δ15N values in M. aeruginosa became increasingly enriched during transport from the C-44 canal (∼5.8 o/oo) into the mid-estuary (∼8.0 o/oo), indicating uptake and growth on sewage N sources within the urbanized estuary. Consequently, there is a need to reduce N and P loading, as well as fecal loading, from the SLE watershed via septic-to-sewer conversion projects and to minimize the frequency and intensity of the releases from Lake Okeechobee to the SLE via additional water storage north of the lake. These enhancements would improve water quality in both the SLE and Lake Okeechobee, reduce the occurrence of toxic harmful algal blooms in the linked systems, and improve overall ecosystem health in the SLE and downstream reefs.
Keywords:Harmful algal blooms  Septic system  Eutrophication  Stable isotopes  Sucralose  Macroalgae
本文献已被 ScienceDirect 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号