A Summit for 



Nutrient 

 Information 



In August, the North 

 Carolina Nutrient Summit 

 will review nutrient enrich- 

 ment from past to present to 

 future. The summit, spon- 

 sored in part by N.C. Sea 

 Grant, N.C. Coastal Federa- 

 tion and N.C. Department of 

 Environment, Health and 

 Natural Resources, will cover 

 sources, impacts, trends, 

 alternative 

 approaches, 

 management 

 strategies and 

 the future. 

 Speakers 

 include 

 James 



Pinckney of 

 the Institute 

 of Marine 

 Sciences in 

 Morehead 

 City, JoAnn 

 Burkholder 

 from the 

 botany 

 department 

 of N.C. State 

 University 

 and Bob 

 Lucas, chair 



of the N.C. Marine Fisheries 

 Commission. 



The summit will be held 

 Aug. 15 and 16 at the Jane 

 S. McKimmon Center at 

 N.C. State University in 

 Raleigh. There will be a $20 

 registration fee before Aug. 5 

 and a $25 fee afterward. Fee 

 includes coffee breaks and a 

 luncheon. 



For more information, 

 contact the N.C. Coastal 

 Federation at 1-800/232-6210 

 or N.C. Sea Grant at 9 19/ 

 515-2454. 



fast the algae are growing, Paerl says. 



Before this technique was devel- 

 oped, scientists could determine how 

 fast an entire community of phytoplank- 

 ton was growing. But now Paerl and 

 Pinckney can simultaneously assess 

 growth rates for a variety of species 

 present in a single sample. 



Although it might seem that most 

 of the Sea Grant researchers' work is in 

 the laboratory, that's not the case. These 

 high-tech lab procedures are allowing 

 the scientists to test a host of hypotheses 

 in the field. 



In ponds behind the Institute of 

 Marine Sciences, Paerl and Pinckney 



A form of blue-green algae 



have set up two rows of circular, 

 translucent fiberglass tanks called 

 hydrocorrals that are 1 meter in diam- 

 eter. The hydrocorrals are filled with 

 water from nearby Bogue Sound. 



The two use the hydrocorrals to test 

 how phytoplankton react to various 

 doses of nitrogen. In one set of corrals, 

 the scientists are testing algal growth 

 rates in response to a single large dose 

 of nitrogen. This simulates what 

 happens after a heavy rainfall when 

 large amounts of nitrogen are dis- 

 charged from municipalities, farms and 

 forests into coastal watersheds. 



Actual rainfall, collected by the 

 researchers, is also added to the corrals. 



Rainfall contains nitrogen from fossil 

 fuel and factory emissions to the 

 atmosphere as well as the ammonia 

 given off from animal lots. But the 

 nitrogen composition of rainfall is 

 different from the nitrogen that washes 

 from fields and forests. Paerl specu- 

 lates that algal species may react 

 differently to the various chemical 

 derivatives of nitrogen and that 

 atmospheric sources of nitrogen may 

 play a greater role in coastal eutrophi- 

 cation than scientists first believed. 



By regularly analyzing samples 

 taken from the hydrocorrals, Paerl and 

 Pinckney can use the techniques 

 described earlier to assess which algal 

 groups and species respond to differ- 

 ent types of nitrogen, how fast each 

 grows and which species dominate. 



In another set of corrals, the 

 scientists administer regular doses of 

 nitrogen to simulate the more constant 

 discharge of nutrients into the water. 

 This treatment mimics waste treatment 

 outfalls, industrial effluents and 

 groundwater outflows. 



In addition to the hydrocorral 

 experiments, Paerl and Pinckney also 

 collect and analyze field samples from 

 the Neuse River, Bogue Sound and a 

 nearshore sampling station. Using 

 information gathered from these sites, 

 they test hypotheses, compare species 

 composition and nutrient levels at 

 different locations, and examine 

 changes in water quality. In essence, 

 they are measuring the pulse of the 

 coastal ecosystem. 



After Paerl and Pinckney enthusi- 

 astically explain the high-tech lab 

 work, the hydrocorrals and sampling 

 procedures, the scientists grow 

 somber. They begin to explain why 

 separating photopigments from algal 

 species has meaning for North 

 Carolinians. 



They want people to see the 

 bigger picture. 



They want everyone to understand 

 that unseen nutrients washing off 

 upstream lands are having profound 

 effects downstream in our coastal 

 waters. 



12 JULY/AUGUST 1995 



