Cyanobac颅teria are among the oldest organ颅isms on earth鈥攖hey were the orig颅inal oxygen-鈥嬧�媝roducing species and are thought to be respon颅sible for the direc颅tion life has taken on earth. Nonethe颅less, they aren't the friend颅liest of species. Cyanobac颅teria pro颅duce neu颅ro颅toxins, which can kill mam颅mals in a matter of hours if ingested.
With today's changing envi颅ron颅ment, cyanobac颅teria are becoming more pro颅lific in water颅ways as dis颅parate as the Charles River in Boston and Lake Taihu in China, said Fer颅di颅nand Hell颅weger, pro颅fessor of civil and envi颅ron颅mental engi颅neering.
Hell颅weger, along with three other prin颅cipal inves颅ti颅ga颅tors from the Uni颅ver颅sity of North Car颅olina, the Uni颅ver颅sity of Ten颅nessee Knoxville and the Uni颅ver颅sity of Texas Austin, have col颅lec颅tively received $2 mil颅lion in funding from the National Sci颅ence Foun颅da颅tion to under颅stand the fac颅tors behind cyanobacteria's increasing presence.
"We know there are links with tem颅per颅a颅ture and nutri颅ents," Hell颅weger said. "But exactly how those things work together to cause this trend is still a mystery."
Lake Taihu is the third largest lake in China, span颅ning more than 2,000 square kilo颅me颅ters. In recent years, cyanobac颅teria have plagued the waterway, which serves as the fresh颅water drinking supply for sev颅eral mil颅lion people. From both a health and an eco颅nomic per颅spec颅tive, this pol颅lu颅tion has the poten颅tial to cause sig颅nif颅i颅cant damage to the society, Hell颅weger said.
Hellweger's col颅lab颅o颅ra颅tors, Hans Paerl (UNC) and Steven Wil颅helm (UT Knoxville), have been working on Taihu for a long time, col颅lecting data on nitrogen and phos颅pho颅rous levels, nutrient set颅tling, and cyanobac颅te颅rial growth rates, for example. "Now it is time develop a model to put all the data together," said Hell颅weger, whose exper颅tise is in mod颅eling com颅plex water sys颅tems for pre颅dic颅tion purposes.
"We want to be able to make pre颅dic颅tions for nutrient reduc颅tion sce颅narios," he con颅tinued. For example, if new policy is geared toward spending mil颅lions of dol颅lars to cut nitrogen levels in half, you'd want to know for sure that the approach would have a sig颅nif颅i颅cant ben颅e颅fi颅cial impact. "But it's very non颅linear," said Hell颅weger, explaining that even small changes in nitrogen or phos颅pho颅rous levels could impact the species that call Taihu home, including cyanobacteria.
Much like the cli颅mate system, he said, there is so much going on that simple rea颅soning is not suf颅fi颅cient for deter颅mining out颅comes. One needs to model many com颅plex mech颅a颅nisms and sys颅tems. But, "a model is always a sim颅pli颅fi颅ca颅tion," he noted. "So we put in what we think is important."
The team will start work by devel颅oping a gene expres颅sion pro颅file of all the organ颅isms in the lake. "This will tell us who's there and what they're doing. It's up to us here at North颅eastern to put it all together in a model, and to try to make sense of it," Hell颅weger said.
If suc颅cessful, the model of Lake Taihu could set a prece颅dent for under颅standing the cyanobac颅teria infes颅ta颅tions of water颅ways across the globe, including the Charles River in the Boston area. His颅tor颅i颅cally, sewage runoff has been the main pol颅lu颅tant in the Charles; today, cyanobac颅teria now shares equal blame in making the Charles River unswim颅mable, according to research at Hellweger's lab. "If cyanobac颅teria are increasing in the Charles," he said, "it would not be sur颅prising to find other local water颅ways next on the list."
Provided by Northeastern University
