{"id":9044,"date":"2016-10-13T20:32:40","date_gmt":"2016-10-14T00:32:40","guid":{"rendered":"https:\/\/ncseagrant.ncsu.edu\/currents\/?p=9044"},"modified":"2024-05-02T15:19:25","modified_gmt":"2024-05-02T19:19:25","slug":"forecasting-hypoxia-algal-blooms-for-the-neuse-river-estuary","status":"publish","type":"post","link":"https:\/\/ncseagrant.ncsu.edu\/currents\/2016\/10\/forecasting-hypoxia-algal-blooms-for-the-neuse-river-estuary\/","title":{"rendered":"Forecasting Hypoxia, Algal Blooms for the Neuse River Estuary"},"content":{"rendered":"

North Carolina Sea Grant-funded scientists are studying hypoxia and algal blooms in the Neuse River Estuary. Photo courtesy UNC IMS<\/em><\/p>\n

By Alexey Katin<\/h3>\n

Hypoxia and algal blooms are common problems in the upper and middle parts of the Neuse River Estuary in North Carolina.<\/p>\n

In the past four decades, rapid growth around the watershed has resulted in the conversion of forests into agricultural and urban landscapes, as well as a rise in wastewater discharge. These changes have increased the amount of nutrients, particularly nitrogen and phosphorus, in the estuary \u2014 what scientists call anthropogenic nutrient loading.<\/p>\n

While hypoxia and algal blooms can occur naturally, anthropogenic nutrient loading has been shown to intensify these phenomena in many coastal systems.<\/p>\n

Frequent algal blooms, identified by elevated chlorophyll concentrations in the water, diminish the aesthetic and recreational value of coastal waters and may produce toxins. When coupled with hypoxia, or severe oxygen depletion, these toxins can cause fish kills and habitat loss \u2014 and may be dangerous to people.<\/p>\n

The Neuse River\u00a0Estuary<\/span> is a critical fisheries and wildlife habitat. Therefore, reducing nutrient loading and improving water quality is an important environmental and societal goal.<\/p>\n

I am part of a multi-institution team studying links among nutrient loading, climate, phytoplankton and dissolved oxygen. This North Carolina Sea Grant-funded study is being led by Daniel Obenour, who is a faculty member of North Carolina State University\u2019s Department of Civil, Construction, and Environmental Engineering. He is collaborating with Hans Paerl<\/a> and Ben Peierls, who study aquatic ecosystems at the University of North Carolina at Chapel Hill\u2019s Institute of Marine Sciences<\/a>.<\/p>\n

We are using data collected from the Neuse River Estuary over the last two decades to model the estuary. This research will test whether the assumptions and processes used in previous studies, some of which were funded by Sea Grant, are consistent with the variability observed in the estuary in recent years.<\/p>\n

The team is focusing on two water-quality parameters \u2014 bottom dissolved oxygen, or DO, and chlorophyll a<\/em> as a proxy for\u00a0surface phytoplankton concentrations \u2014 to analyze the current state of the estuary and its transformation over time, based on existing data.<\/p>\n

\"Green<\/a>

Surface chlorophyll a<\/em> concentrations \u2014 that can indicate algal blooms \u2014 for May through November in the upper, middle and lower estuary segments from 1997 to 2015. Intense green indicates high surface chlorophyll a<\/em> concentration. Big fish icons stand for a fish kill event with more than 5,000 dead fishes, while small icons show cases with less than 5,000 dead fishes. Click image to enlarge.<\/p><\/div>\n

\"Varying<\/a>

Bottom dissolved oxygen concentrations for May through November in the upper, middle and lower estuary segments from 1997 to 2015. Intense red color indicates low bottom DO concentration. Big fish icons stand for a fish kill event with more than 5,000 dead fishes, while small icons show cases with less than 5,000 dead fishes. Click image to enlarge.<\/p><\/div>\n

So far, our initial analysis of data from 1994 to 2015 has revealed some interesting features:<\/p>\n