Looking for answers in a bloom 



All the conditions were right. Warm 

 water — above 70 degrees Fahrenheit. 

 Long, sunny days. A stratified water 

 column with low river flow and calm 

 wind. And, most important, plenty of 

 nutrients. 



The river was ripe for a bloom. The 

 blue-green algal cells multiplied 

 rapidly by division. The organisms 

 gathered, rose to the surface and 

 formed colonies. Soon the scum float- 

 ed in big patches. The nuisance algae 

 were taking over, and it would be 

 months before the bloom's demise. 

 And, even then, its effects would linger 

 long after. 



Sea Grant researchers Hans Paerl, 

 Donald Stanley and Robert Christian 

 have been studying the blue-green 

 algal problem on the Neuse River. 

 And, they all agree. Underneath all 



*, Photo by Neil Caudle 



that scum, even more drastic changes 

 may be occurring — changes that may 

 alter the chemical and biological make- 

 up of the river. 



Scientists attribute the blooms to 

 the excess of nutrients being pumped 

 into the river from upstream. (See 

 story, page 4). Paerl has found that 

 factors such as oxygen, salinity levels, 

 temperature and sunlight affect the 

 production and survival of blue-green 

 algae. The difference between a bloom 

 year and a non-bloom year is usually 

 attributed to hydrological or climatic 

 conditions, he says. Last year, for ex- 

 ample, there wasn't a bloom on the 

 Neuse because of the high river flow. 



Other algae, some of which are 

 desirable food sources for other 

 organisms, fare badly when the blue- 

 greens begin to take over. A blue-green 



Surface slime layer of blue-green algae and bacteria (top); Paerl's cultured algae stored in a refrigerator 



