(Press-News.org) Continued eutrophication of the Baltic Sea, combined with an ever thinner ozone layer, is favouring the toxic cyanobacterium Nodularia spumigena, reveals research from the University of Gothenburg, Sweden.
"There are several species of cyanobacteria, or blue-green algae, that can form surface blooms in the Baltic Sea," explains Malin Mohlin from the University of Gothenburg's Department of Marine Ecology. "Which species ends up dominating a bloom depends partly on how they deal with an increased amount of UV light and a shortage of nutrients. Nodularia spumigena is most toxic when there is little nitrogen in the water but sufficient amounts of phosphorus."
As a result, wastewater treatment processes that concentrate on removing nitrogen can make cyanobacterial blooms more toxic. Wastewater therefore needs to be cleared of both nitrogen and phosphorus.
Mohlin's research shows that Nodularia spumigena can be expected to be most toxic at the beginning of a bloom in July. At that time there is generally more phosphorus than nitrogen in the water, and the cyanobacteria have not yet to float to the surface but are found deeper in the water where they have not yet been exposed to UV light.
Surface blooms of cyanobacteria, which are a type of phytoplankton, have increased in both frequency and magnitude in the Baltic Sea in recent decades, and researchers are divided on the cause. Some put it down to eutrophication – an excess of nutrients in the water – caused by human emissions of nitrogen and phosphorus over the past 150 years. Others have studied the Baltic Sea's bottom sediment and argue that this is a natural phenomenon that has been ongoing for more than 7,000 years and is due instead to climate variations.
Different species of nitrogen-fixing cyanobacteria bloom at different times. Aphanizomenon species tend to bloom from May to June, but from July to August the toxic species Nodularia spumigena normally dominates for as long as the surface water is warm and still.
The toxin it produces is called nodularin and is a hepatotoxin – a toxin that attacks the liver. Livestock and dogs around the Baltic Sea have died after consuming large quantities of toxic water during blooms.
INFORMATION:
The thesis has been successfully defended.
Eutrophication makes toxic cyanobacteria more toxic
2010-12-07
ELSE PRESS RELEASES FROM THIS DATE:
Exposure to mobile phones before and after birth linked to kids' behavioral problems
2010-12-07
Pregnant mums who regularly use mobile phones may be more likely to have kids with behavioural problems, particularly if those children start using mobile phones early themselves, suggests research published online in the Journal of Epidemiology and Community Health.
The researchers base their findings on more than 28,000 seven year olds and their mothers who were part of the Danish National Birth Cohort (DNBC) study.
This study enrolled nearly 100,000 pregnant women between 1996 and 2002, with the intention of tracking their kids' long term health.
The mums supplied ...
Ban electronic cigarettes until safety concerns are addressed, say researchers
2010-12-07
Regulatory authorities should consider banning electronic cigarettes until safety concerns have been addressed, concludes research published online in Tobacco Control.
The researchers base their conclusions on an evaluation of six different brands of electronic nicotine delivery systems or ENDS. These are not tobacco products, but are designed to look and feel like regular cigarettes.
They are aimed at smokers for use in places where cigarette smoking is not permitted as they don't produce smoke. They usually consist of a battery, an atomiser, and a replaceable cartridge ...
Flu vaccination disparities exacerbated by supply problems
2010-12-07
The gap in flu vaccination rates between elderly whites, African-Americans and Hispanics is amplified when vaccine supply is limited or delayed. That is the conclusion of a study out today in the American Journal of Preventive Medicine.
The study found that disparities in seasonal influenza vaccination rates between the groups grew by as much as 7 percentage points in years when there were problems with vaccine supply. By contrast, the gap narrowed by as much as 11 percentage points during years when the supply was more timely and abundant.
"There is a strong ...
Shy trout size it up
2010-12-07
Personality is not just a feature unique to humans and pets. Scientists at the University of Gothenburg (Sweden) have revealed that also brown trout have individual characters and show different personalities.
Researcher Bart Adriaenssens from the Department of Zoology at the University of Gothenburg has for many years studied the behaviour of juvenile trout from watercourses on the west coast of Sweden.
"My results show that it are not just humans and other mammals that exhibit personality. Also brown trout differ among each other in their level of aggression and react ...
2 studies provide insight into stroke risk and prevention in young sickle cell anemia patients
2010-12-07
Monthly blood transfusions combined with daily medication to remove the resulting excess iron remains the best approach for reducing the risk of recurrent strokes in young patients with sickle cell anemia, according to a preliminary analysis of a multicenter trial that includes St. Jude Children's Research Hospital.
The study compared the efficacy of two treatments for the potentially life-threatening problem of iron overload caused by chronic transfusion therapy. The transfusions are used to guard against additional strokes in young sickle cell anemia patients. The trial, ...
New tool in the early detection of bowel disease
2010-12-07
An international team of researchers led by the University of East Anglia (UEA) have developed a new kind of endoscope to aid the early detection and diagnosis of inflammatory bowel disease.
The Confocal Laser Endomicroscope (CLE) contains a powerful microscope which allows clinicians to view the bacteria that are thought to trigger diseases of the bowel such as Crohn's disease and ulcerative colitis.
"Bacteria within the wall of the gut are already believed to play an important role in the development of inflammatory bowel disease and we now have a powerful new tool ...
Researchers discover a way to delay Christmas tree needle loss
2010-12-07
Quebec City, December 6, 2010—Researchers at Université Laval, in collaboration with Nova Scotia Agricultural College, have discovered what causes Christmas tree needles to drop off, and how to double the lifespan of Christmas trees in homes. The authors presented their findings in a recent issue of the scientific journal Trees.
The researchers have identified a plant hormone—ethylene—responsible for needle loss in balsam fir. They made the discovery by placing fir branches in containers of water inside a growth chamber. After ten days the branches began to produce ethylene ...
Brand recognition can help hotels survive economic downturns
2010-12-07
Brand named hotels fare better than independently operated properties in economic downturns, according to a team of international researchers.
A study of the performance of hotels during both economic recessions and expansions indicates that brand named hotels are more profitable than independent hotels under all economic conditions, but the difference is particularly significant during recessions, said John O'Neill, associate professor of hospitality management, Penn State.
"There has been a lot of debate in the hotel industry about the advantages of brand affiliation ...
Study reveals how taking an active role in learning enhances memory
2010-12-07
CHAMPAIGN, Ill. — Good news for control freaks! New research confirms that having some authority over how one takes in new information significantly enhances one's ability to remember it. The study, in the journal Nature Neuroscience, also offers a first look at the network of brain structures that contribute to this phenomenon.
"Having active control over a learning situation is very powerful and we're beginning to understand why," said University of Illinois psychology and Beckman Institute professor Neal Cohen, who led the study with postdoctoral researcher Joel Voss. ...
AgriLife researchers find way to cut food-irradiation levels by half
2010-12-07
COLLEGE STATION — A team of Texas AgriLife Research engineers has developed a way to cut by as much as half the amount of irradiation needed to kill 99.999 percent of salmonella, E. coli and other pathogens on fresh produce.
By packing produce in a Mylar bag filled with pure oxygen, Dr. Carmen Gomes, AgriLife Research food safety engineer, and her colleagues found they could significantly reduce the amount of radiation needed to kill those pathogens. Reducing the amount of radiation is not so much a safety measure as it is a way to preserve quality of the produce, she ...