Waterbuffalo
07-18-2008, 03:31 AM
http://www.columbian.com/news/localNews/2008/07/07172008_Worrisome-waters-100000-study-confirms-Vancouver-Lake-often-teems-with-bacteria-but-doesnt-say-what-to-do-about-it.cfm
Thursday, July 17, 2008
By ERIK ROBINSON, Columbian staff writer
Vancouver Lake is a popular summertime retreat for swimmers and boaters. For cyanobacteria — commonly known as blue-green algae — summer at the lake is the bacteria world’s version of New Orleans at Mardi Gras.
Researchers with Washington State University Vancouver spent the past year conducting a microscopic census of the unseen mass of plant and bacteria life teeming just beneath the lake’s surface. On Wednesday, the researchers revealed findings from a yearlong $100,000 study of the lake’s microscopic inhabitants.
They collected water samples from March 2007 to February of this year, finding an “extremely high abundance” of cyanobacteria beginning last July.
“We did see an enormous plume of cyanobacteria,” Gretchen Rollwagen-Bollens, a WSU marine ecologist, told members of the Vancouver Lake Watershed Partnership. “Throughout the winter, we don’t see them really at all.”
(The lake currently remains safe for swimming. Health authorities are sampling water regularly in anticipation of another bloom producing toxins that can harm people or kill small pets that drink the water.)
WSU’s findings didn’t come as news to local health authorities, who have closed the lake during the past several summers due to toxic cyanobacteria blooms. Rollwagen-Bollens and Steve Bollens, director of science programs at WSU, did not reveal how to prevent such blooms in the future.
“This is a very complex, complicated question,” Bollens said.
The partnership formed in 2004 to address a well-documented series of problems in Vancouver Lake.
The shallow lake is becoming clogged with silt; it is routinely closed in the summer due to blooms of toxic cyanobacteria; and pollution-laden runoff continues to pour in from creeks that cut through the heart of Clark County’s most urbanized areas.
The WSU researchers, who summarized their findings during a regular monthly meeting of the partnership Wednesday at the Port of Vancouver’s administrative office, offered no easy solutions.
The findings form a foundation for building knowledge about the lake’s ecology, Bollens said.
It shows how populations of zooplankton, phytoplankton and bacteria wax and wane throughout the year and appear to be dispersed uniformly across the 2,600-acre lake.
The findings also provided some clues about certain types of zooplankton whose population boom and bust shadowed the summertime rise and fall of cyanobacteria.
“That suggest there may be a predator-prey relationship,” Bollens said.
The next step: more study.
The partnership collects its funding from the Port of Vancouver, Clark County and the city of Vancouver.
Ron Wierenga, a county water quality specialist who has served as the partnership’s technical adviser, said the group expects to pay another $75,000 to $80,000 to underwrite another year of research. Bollens said the next year’s research will focus on the growth and death rates of all the lake’s microscopic life forms — and how they are affected by factors such as an overabundance of nutrients.
“Probably the biggest source is runoff from the watershed, which has been heavily developed,” Bollens said.
Nitrogen and phosphorous flow into the lake from lawn fertilizers, as does agricultural runoff and human and animal waste draining into Burnt Bridge Creek and Lake River. Although Lake River drains out of Vancouver Lake — as does a flushing channel built by the Port of Vancouver two decades ago — the flow of water can be reversed by high tides in the Columbia River.
Cyanobacteria blooms afflict plenty of lakes, but Bollens told members of the partnership that the suspected triggers vary wildly from lake to lake. Those factors include the interplay of sunlight, nutrients, temperature, water flow, and the presence of microscopic “grazers” capable of holding blooms in check.
“There has been quite a bit of work in North America and Europe,” Rollwagen-Bollens said. “But there are a lot of unanswered questions, considering this is such a problem in so many places.”
“A lot of money’s been thrown at the problem, unsuccessfully,” Wierenga said. “Do we want to study the situation forever? No. But we want to be careful in what we do.”
Thursday, July 17, 2008
By ERIK ROBINSON, Columbian staff writer
Vancouver Lake is a popular summertime retreat for swimmers and boaters. For cyanobacteria — commonly known as blue-green algae — summer at the lake is the bacteria world’s version of New Orleans at Mardi Gras.
Researchers with Washington State University Vancouver spent the past year conducting a microscopic census of the unseen mass of plant and bacteria life teeming just beneath the lake’s surface. On Wednesday, the researchers revealed findings from a yearlong $100,000 study of the lake’s microscopic inhabitants.
They collected water samples from March 2007 to February of this year, finding an “extremely high abundance” of cyanobacteria beginning last July.
“We did see an enormous plume of cyanobacteria,” Gretchen Rollwagen-Bollens, a WSU marine ecologist, told members of the Vancouver Lake Watershed Partnership. “Throughout the winter, we don’t see them really at all.”
(The lake currently remains safe for swimming. Health authorities are sampling water regularly in anticipation of another bloom producing toxins that can harm people or kill small pets that drink the water.)
WSU’s findings didn’t come as news to local health authorities, who have closed the lake during the past several summers due to toxic cyanobacteria blooms. Rollwagen-Bollens and Steve Bollens, director of science programs at WSU, did not reveal how to prevent such blooms in the future.
“This is a very complex, complicated question,” Bollens said.
The partnership formed in 2004 to address a well-documented series of problems in Vancouver Lake.
The shallow lake is becoming clogged with silt; it is routinely closed in the summer due to blooms of toxic cyanobacteria; and pollution-laden runoff continues to pour in from creeks that cut through the heart of Clark County’s most urbanized areas.
The WSU researchers, who summarized their findings during a regular monthly meeting of the partnership Wednesday at the Port of Vancouver’s administrative office, offered no easy solutions.
The findings form a foundation for building knowledge about the lake’s ecology, Bollens said.
It shows how populations of zooplankton, phytoplankton and bacteria wax and wane throughout the year and appear to be dispersed uniformly across the 2,600-acre lake.
The findings also provided some clues about certain types of zooplankton whose population boom and bust shadowed the summertime rise and fall of cyanobacteria.
“That suggest there may be a predator-prey relationship,” Bollens said.
The next step: more study.
The partnership collects its funding from the Port of Vancouver, Clark County and the city of Vancouver.
Ron Wierenga, a county water quality specialist who has served as the partnership’s technical adviser, said the group expects to pay another $75,000 to $80,000 to underwrite another year of research. Bollens said the next year’s research will focus on the growth and death rates of all the lake’s microscopic life forms — and how they are affected by factors such as an overabundance of nutrients.
“Probably the biggest source is runoff from the watershed, which has been heavily developed,” Bollens said.
Nitrogen and phosphorous flow into the lake from lawn fertilizers, as does agricultural runoff and human and animal waste draining into Burnt Bridge Creek and Lake River. Although Lake River drains out of Vancouver Lake — as does a flushing channel built by the Port of Vancouver two decades ago — the flow of water can be reversed by high tides in the Columbia River.
Cyanobacteria blooms afflict plenty of lakes, but Bollens told members of the partnership that the suspected triggers vary wildly from lake to lake. Those factors include the interplay of sunlight, nutrients, temperature, water flow, and the presence of microscopic “grazers” capable of holding blooms in check.
“There has been quite a bit of work in North America and Europe,” Rollwagen-Bollens said. “But there are a lot of unanswered questions, considering this is such a problem in so many places.”
“A lot of money’s been thrown at the problem, unsuccessfully,” Wierenga said. “Do we want to study the situation forever? No. But we want to be careful in what we do.”