Hans Paerl has spent nearly 20 years studying the troubled waters of the Neuse River. 

 His results have helped shape public policy. 



Unfortunately, the Neuse' s 

 "normal" hasn't been good for some time. 



Mats of algal blooms have choked 

 its waters, leading to foul odors, oxygen 

 depletion in the bottom waters and 

 toxicity. Scores of fish have died. 



Still, it is not easy to predict the 

 river's behavior because the environ- 

 mental factors that control algal bloom 

 dynamics vary tremendously from 

 season to season and from year to year. 

 Paerl says this problem makes it 

 difficult to devise a mathematical model 

 to explain what is happening to the 

 water quality and to tell whether a 

 particular management strategy is working. 



"Modeling efforts will only be as 

 good as the environmental data that are 

 needed to establish long-term trends and 

 degrees of variability, which will help us 

 to distinguish human from natural 

 impacts on water quality," Paerl says. 



For example, the amount of 

 nitrogen input — which Paerl helped 

 determine was a key factor controlling 

 algal growth in the Neuse — has 

 bounced back and forth over the past 

 five years. It rose from 1994 to 1996 

 before falling in 1997 and beginning to 

 soar in 1998. 



In another quirky indicator, so much 

 rain fell at the beginning of the year that 

 more fresh water flowed into the Neuse by 

 May than in the entire year before. 



"By solely evaluating highly 

 variable short-term trends, one can 

 erroneously conclude that the system is 

 getting better or worse," Paerl says. 

 "Only by teasing the short-term 'noise' 

 from the long-term 'signal' can we 

 establish a reliable trend." 



That's why researchers need long- 

 term data sets, and that's why it's 

 important to continue the monitoring 

 well after the modeling, Paerl says. He 

 credits organizations such as North 

 Carolina Sea Grant, the National 

 Science Foundation, the Environmental 

 Protection Agency, the U.S. Department 

 of Agriculture, the U.S. Geological 

 Survey /Water Resources Research 

 Institute and the state Division of Water 

 Quality with providing the dollars to 



carry out years of vital monitoring 

 activities accompanying research grants. 



"To really test these models, you 

 have to continue monitoring," Paerl says. 

 "The proof is in what the environment is 

 telling you in the long run. This is 

 particularly critical for evaluating the 

 effectiveness of management steps, such 

 as nutrient input constraints, mandated for 

 improving water quality. You've heard 

 the expression, 'It took a long time for us 

 to get in this mess.' It might take decades 

 for the system to recover and the water 

 quality to improve." 



Rick Luettich, an associate professor 

 of marine sciences and environmental 

 sciences and engineering at IMS, says, 

 "There's this general perception that you 

 can throw money at something for a year 

 or two and fix it, but that totally under- 

 estimates a complex natural system like 

 an estuary." 



The research conducted on the Neuse 

 River over the years has made a differ- 

 ence. In the late 1980s, the legislature 

 enacted a ban on phosphates based partly 

 on this research. As a result, the upstream 

 sections of the Neuse are less plagued by 

 algal blooms, Paerl says. 



Now scientists have also identified 

 nitrogen as a crucial ingredient for algal 

 growth in the lower part of the river. 



Partially as a result of these findings, the 

 General Assembly has called for a 30 

 percent reduction in the amount of 

 nitrogen flowing into the Neuse. 



Paerl says he knows some people 

 tire of hearing about year after year of 

 scientific study. They say it's time to 

 stop studying and start acting. 



But as monitoring continues and 

 the years advance, the research tools 

 improve and yield better information. 

 Now, for example, researchers can 

 measure bioactive substances such as 

 antibiotics, plant growth regulators and 

 modifiers, and various forms of growth- 

 promoting nitrogen and phosphorus in 

 the water that they couldn't before. 



Paerl particularly applauds the 

 Neuse River Estuary MODeling and 

 MONitoring project (or MODMON), 

 which includes scientists from UNC- 

 Chapel Hill, North Carolina State 

 University, Duke University, East 

 Carolina University, UNC-Charlotte, 

 the U.S. Geological Survey, the state 

 Division of Water Quality and the 

 Weyerhaeuser Corp. 



Whereas the Neuse got only 

 monthly checkups during the 1970s, 

 "now we have probably one of the 

 finest coordinated sampling systems in 

 the nation," Paerl says. "The system is 



Continued 



COASTWATCH 21 



