Growth of natural phytoplankton populations of Wilson Bay : a nutrient bioassay approach

• Main Authors: Brousseau, Jennifer Peterson, NC DOCKS at The University of North Carolina Wilmington
• Language: English
• Published: 2009
• Subjects: Algal blooms > North Carolina > New River Estuary; Phytoplankton > Nutrition > Research; Water > Nitrogen content; New River Estuary (Onslow County; N.C.) > Research; Nutrient pollution of water > North Carolina > New River Estuary; Water quality bioassay > North Carolina > New River Estuary; Wilson Bay
• Online Access: http://libres.uncg.edu/ir/uncw/f/brousseauj2005-1.pdf

Wilson Bay is a shallow estuarine embayment found within the New River Estuary. Previous work sponsored by NC WRRI examined phytoplankton bloom species composition, rainfall and nutrient levels within the New River Estuary. This study focused on the influence of nutrients in forming blooms using a bioassay format measuring phytoplankton growth over a 7 day incubation period. Growth rates were measured by fluorometric readings and visual eye counts preformed on natural populations that were incubated and treated with nutrient addition and exclusions. Additions consisted of sodium nitrate (NaNo3), ammonium chloride (NHCl), urea (CO(NH2)2) and a complete control, including phosphate, silicate, vitamins and trace metals. Exclusions minus nitrogen, minus phosphate, minus silicate, and unenriched controls were also measured. Ambient nutrient levels were measured in sample water before nutrients were added. Previous work done on Wilson Bay showed to often be nitrogen limiting. The unexpected amounts of rainfall during the study period provided data that showed that Wilson Bay was nitrogen limited with nitrogen additions giving the greatest stimulation. The study period (March-September 2003) had abundant amounts of rainfall compared to the previous (2002) which was a drought years. Wilson Bay blooms are strongly affected by local weather and the rate and types of nutrient delivery.