1 research outputs found
Stimulation of Phytoplankton Production by Anthropogenic Dissolved Organic Nitrogen in a Coastal Plain Estuary
There
is increased focus on nitrogen (N)-containing dissolved organic
matter (DOM) as a nutrient source supporting eutrophication in N-sensitive
estuarine ecosystems. This is particularly relevant in watersheds
undergoing urban and agricultural development, leading to increased
dissolved organic N (DON) loading. To understand how this shift in
N-loading influences estuarine phytoplankton production, nutrient
addition bioassays were conducted in the N-limited Neuse River Estuary,
North Carolina from 2014 to 2015. Additions included N-rich DOM sources
characteristic of urban and agricultural development, including chicken
and turkey litter leachate, wastewater treatment facility effluent,
and concentrated river DOM (used as a reference). Each DOM addition
was coupled with an inorganic nutrient treatment to account for inorganic
nutrient concentrations (NO<sub>2/3</sub>, NH<sub>4</sub>, PO<sub>4</sub>) in each respective DOM addition. Repeated measures analysis
of variance (RM-ANOVA) showed that chicken litter leachate stimulated
phytoplankton growth greater than its coupled inorganic nutrient treatment.
Wastewater treatment facility effluent, turkey litter leachate, and
concentrated river DOM did not stimulate phytoplankton growth greater
than their respective inorganic nutrient controls. DOM fluorescence
(EEM-PARAFAC) indicated the chicken litter contained a biologically
reactive fluorescent DOM component, identified as the nonhumic, biologically
labile, “N-peak”, which may be responsible for stimulating
the observed phytoplankton growth in the chicken litter leachate treatments