Death from below: Investigation of inhibitory factors in bloom development during a wastewater effluent diversion

TitleDeath from below: Investigation of inhibitory factors in bloom development during a wastewater effluent diversion
Publication TypeJournal Article
Year of Publication2017
AuthorsKudela R.M, Lucas A.J, Hayashi K., Howard M., McLaughlin K.
JournalEstuarine Coastal and Shelf Science
Date Published2017/02
Type of ArticleArticle
ISBN Number0272-7714
Accession NumberWOS:000399623900005
Keywordsammonium; Ammonium compounds; chlorination; disinfection by-products; Effluents; estuary; eutrophication; fluorescence; Harmful algal blooms; Marine & Freshwater Biology; oceanography; photosynthesis; phytoplankton; phytoplankton blooms; river; southern california; Variable; Wastewater treatment

Eutrophication of coastal waters is an urgent and globally increasing problem. A significant source of nutrients to Southern California coastal waters is direct discharge of secondarily treated wastewater effluent from regional Publicly Owned Treatment Works. The planned diversion of treated wastewater from the Orange County Sanitation District's main (5-mile) pipe to a shallow 1-mile pipe off Huntington Beach, CA in autumn 2012 provided an unprecedented opportunity to monitor the response of the coastal phytoplankton community to a major anthropogenic loading event. Despite the continuous release of approximately 11.07 x 10(6) m(3) of effluent containing 1743 mu M ammonium, there was virtually no detectable change in phytoplankton biomass, in striking contrast to the harmful algal bloom dominated community that quickly developed in response to a comparable diversion in Santa Monica Bay in 2006. Field and laboratory studies demonstrate that disinfection byproducts associated with enhanced dechlorination were present in the discharged water, and that these compounds had a strong inhibitory impact on phytoplankton photophysiology and growth, lasting 24 h for photosynthetic performance and at least 3 d for growth, assessed as change in chlorophyll. Thus, the perhaps fortuitous unintended consequence of enhanced chlorination was the production of inhibitory compounds that suppressed the potential phytoplankton response over a large swath of the continental shelf during the diversion. (C) 2015 The Authors. Published by Elsevier Ltd.

Short TitleEstuar. Coast. Shelf Sci.
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