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 Treatment of saline wastewater during algae utilization
14.05.2019 | Jacobs University Bremen gGmbH

nachricht Plastic gets a do-over: Breakthrough discovery recycles plastic from the inside out
07.05.2019 | DOE/Lawrence Berkeley National Laboratory

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: New studies increase confidence in NASA's measure of Earth's temperature

A new assessment of NASA's record of global temperatures revealed that the agency's estimate of Earth's long-term temperature rise in recent decades is accurate to within less than a tenth of a degree Fahrenheit, providing confidence that past and future research is correctly capturing rising surface temperatures.

The most complete assessment ever of statistical uncertainty within the GISS Surface Temperature Analysis (GISTEMP) data product shows that the annual values...

Im Focus: The geometry of an electron determined for the first time

Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.

The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or...

Im Focus: Self-repairing batteries

UTokyo engineers develop a way to create high-capacity long-life batteries

Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...

Im Focus: Quantum Cloud Computing with Self-Check

With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.

Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...

Im Focus: Accelerating quantum technologies with materials processing at the atomic scale

'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.

However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

New system by TU Graz automatically recognises pedestrians’ intent to cross the road

27.05.2019 | Information Technology

On Mars, sands shift to a different drum

24.05.2019 | Physics and Astronomy

Piedmont Atlanta first in Georgia to offer new minimally invasive treatment for emphysema

24.05.2019 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>