Photo from UNC Institute of Marine Sciences 



Microcystis aeruginosa, under the microscope; Paerl sampling bloom-prone Neuse 



Two new looks 

 At a deadly bloom 



The problem: blue-green algae blooms on coastal 

 rivers which may alter the ecosystems downstream 

 in the estuary 



During the summer the pungent odor of decaying 

 algae pervades the air along the Neuse River. The paint- 

 like scum invades the river from Kinston to New Bern. 

 Citizens, scientists, fishery managers and state officials 

 are concerned about the blue-green algae blooms, hoping 

 to prevent the problems occurring on the Chowan River, 

 further to the north. 



Scientists believe high levels of two nutrients, nitrogen 

 and phosphorus, trigger the blooms. And the Neuse 

 River is chocked full of nutrients. Known point sources 

 of nutrients, such as city waste treatment plants and in- 

 dustry, dumped 2.37 million pounds of nitrogen and 1 

 million pounds of phosphorus into the Neuse in 1981. 

 And no one knows the levels of nutrients that arrive in 

 the rivers from non-point sources such as land run-off. 



Earlier studies that focused on algal blooms on the 

 Chowan will provide a foundation for research begin- 

 ning on the Neuse. In a Sea Grant study begun last year, 

 Hans Paerl studied how far into the Neuse estuary the 

 blooms penetrated and how factors like salinity and 

 nitrogen-availability limited the penetration. Donald 

 Stanley and Robert Christian examined the factors that 

 trigger algal blooms and the effects of reduced nutrient- 

 loading on bloom formation in the Neuse River. 



But Paerl, Stanley and Christian have just scratched 

 the surface of a very complicated ecological problem. 

 More research is needed to learn how these massive 

 blooms affect the estuaries and subsequently the fisheries 

 production downstream. 



The research: studies into the chemical and 

 biological fate of blue-green algae blooms in the 

 estuary 



Upstream blue-green algae paints the river in a foul- 

 smelling scum, making it unfit for recreation and, oc- 

 casionally, fatal to fish. Downstream in the estuary no 

 evidence of the bloom is evident. But beneath the water's 

 surface, the decaying bloom may be causing drastic 

 changes in the chemical and biological makeup of the es- 

 tuary. And Paerl wants to find what kind of biological 

 changes are occurring. 



Zooplankton, a major food source for many developing 

 fish and shellfish in the estuary, feeds on phytoplankton. 

 But during the past five years the phytoplankton com- 

 munity, which serves as the base of the food chain, has 

 undergone major change. Blue-green algae now makes up 

 the bulk of the phytoplankton present in the lower Neuse 

 River between May and September. And early studies 

 indicate blue-green algae may not be a nutritional food 

 source for zooplankton. 



Paerl will be studying blue-green algae's impact on the 

 food chain. He wants to find out if the zooplankton can 

 digest the algae or whether they shun it, perhaps creating 

 a break in the food chain. 



The findings of Paerl's studies will not only reveal how 

 the algae affects zooplankton food sources, but will also 

 show how algae changes food sources further along the 

 food chain. Today's algae blooms could have profound 

 effects on tomorrow's fish and shellfish populations. 



In a sister study, Stanley and Christian will be study- 

 ing the chemical fate of blue-green algae blooms in the 

 Neuse River estuary. They will be taking a special look 

 at what happens as the blooms are carried downstream to 

 where fresh water and saline water meet. Earlier studies 

 indicated algae are intolerant of even low salinities. 

 Biogeochemical changes are believed to cause the algae's 

 intolerance. Stanley and Christian will be testing this 

 hypothesis. 



The research team will also study what happens 

 downstream in the estuary after the algae decays. Blue- 



