Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Harmful cyanobacteria benefit from global warming

08.04.2008
‘Blooms like it hot’, argue two prominent biologists in this week’s issue of Science. Global warming creates favorable conditions for harmful cyanobacteria, because they respond more strongly to rising temperatures than most other algal species. This is likely to affect the water quality of many aquatic ecosystems worldwide, especially during summer heatwaves.

Blooms of harmful cyanobacteria (also known as bluegreen algae) are a growing nuisance in many lakes in Africa, Australia, China, the USA, and in many European waters. Professor Hans Paerl of the University of North Carolina (USA) and professor Jef Huisman of the University of Amsterdam (Netherlands) conclude on the basis of several recent studies that the worldwide proliferation of harmful cyanobacterial blooms is linked to climate change.

Cyanobacteria flourish at high temperatures, especially in nutrient-rich waters with high concentrations of nitrogen and phosphorus. The surface water of lakes is heated during prolonged periods of warm weather. Warm water expands, and floats on the colder water underneath. This results in stratification of lake water, which suppresses vertical mixing. Cyanobacteria profit from these stratified conditions.

They make small gas vesicles inside their cells, providing buoyancy. Buoyant cycanobacteria float upwards when vertical mixing is weak and accumulate in dense surface blooms. These surface blooms shade underlying nonbuoyant phytoplankton (such as green algae and diatoms). Thus, surface blooms of buoyant cyanobacteria effectively suppress other species by monopolizing all available light.

Changes in precipitation patterns and summer droughts

Cyanobacteria also profit from changes in precipitation patterns and summer droughts. Climate models predict more intense precipitation interspersed by longer periods of drought as a result of global warming. Intense precipitation leaches nutrients from soils, flushing them into rivers and lakes. As the discharge subsides during subsequent periods of warm, dry weather, cyanobacteria can capture the extra nutrient load, promoting their bloom development.

Attempts to control the water table by closure of dams and sluices during summer droughts may further aggrevate the problem. This will increase the residence time of cyanobacteria in these stagnant waters, thus providing a longer time window for bloom development. Moreover, cyanobacteria appear to be more salt-tolerant than other freshwater algal species. Rising salinities due to increased evaporation or salt water intrusion from sea level rise may thus give cyanobacteria an additional competitive advantage.

Paerl and Huisman discuss the example of a tropical cyanobacterium responsible for a severe outbreak of hepatitis on Palm Eiland, Australia. This tropical species invaded southern Europe in the 1930s, and has subsequently expanded its range northwards to lakes in the Netherlands and Northern Germany. Likewise, the species also invaded Florida several decades ago, and is now widespread across the US southeast and midwest, where it proliferates in warm and nutrient-rich waters. ‘Water managers will have to anticipate a worldwide expansion of harmful cyanobacteria’, says Huisman. ‘This is another important reason to curb the emission of greenhouse gases’.

Cyanobacteria can produce a variety of different toxins, causing damage to the liver and nervous system of birds and mammals in particular. Ingestion of these toxins can be fatal to cattle, waterfowl, and pets, and is also a serious threat for human health. Bodies of waters are closed for recreation and agricultural use, when their concentrations of cyanobacteria exceed a critical threshold level.

Josje Spinhoven | alfa
Further information:
http://www.uva.nl

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Designer cells: artificial enzyme can activate a gene switch

22.05.2018 | Life Sciences

PR of MCC: Carbon removal from atmosphere unavoidable for 1.5 degree target

22.05.2018 | Earth Sciences

Achema 2018: New camera system monitors distillation and helps save energy

22.05.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>