Low Dissolved Oxygen Predicted In The Neuse River Estuary

Jul 18, 2018

Credit UNC Institute of Marine Sciences

An experimental model is forecasting significantly low dissolved oxygen levels in the Neuse River Estuary, which could trigger algal blooms and fish kills.  

July and August tend to be more severe months for low dissolved oxygen levels, also called hypoxia.  But a model developed by researchers at North Carolina State University and the University of North Carolina’s Institute of Marine Sciences in Morehead City is predicting this year could be worse.  There’s likely two main reasons for the low levels of dissolved oxygen.  One, a low river flow rate this winter caused organic material to build up in the estuary, said Daniel Obenour, assistant professor with NCSU's Department of Civil, Construction, and Environmental Engineering.

“The other factor is that we had a really wet spring.  When we have these high flows, a lot of rain in the spring, that washes nutrients into the water in to the river, which brings it down into the estuary.”

Obenour said the combination of organic material and an increase in nitrogen and phosphorus from surface water runoff fuels algal blooms.

“And so you end up with just a lot of material to be decomposed by the microbes in the estuary and that’s what leads to hypoxia.”

Last week, Tropical Storm Chris helped reoxygenate the Neuse River as passed well off the coast, but Obenour said the effect is only temporary. Hypoxic conditions are forecasted to last through August.