Tag Archives: Algal blooms

Warming bad for life in freshwater lakes and rivers

For immediate release On both sides of the Atlantic scientists studying lakes have discovered they are warming – and this is bad news both for water quality and the fish. London, 14 June – The Alpine lakes of Austria are warming up. By 2050, their surface waters could be up to 3°C warmer, according to new research in the journal Hydrobiologia. Martin Dokulil of the Institute for Limnology at the University of Innsbruck studied data from nine lakes larger than 10km2. The largest, Bodensee or Lake Constance, touches Austria’s border with Germany and Switzerland to the west; 800 kms to the east, Neusiedler See borders Germany and Hungary. The nine lakes range from 254 to 1.8 metres maximum depth and they are vital to Austria’s tourist industry: they play powerful roles in the Alpine ecosystem and they are of course reservoirs of water. But the Alpine valleys are warming: between 1980 and 1999 the region warmed at three times the global average and by 2050 the median temperatures for the region could have risen by 3.5°C. The challenge has been to anticipate the impact of global warming on the lakes. “The predicted changes in surface water temperatures will affect the thermal characteristics of the lakes,” says Dr Dokulil. “Warmer water temperatures could lead to enhanced nutrient loads and affect water quality by promoting algal blooms and impairing the biological functions of aquatic organisms. “Significant increases in summer temperatures will affect the carbon cycling in the lakes, with potential consequences on atmospheric carbon dioxide levels and the Earth’s climate.”  Next, the fish The Austrian research so far is concerned only with freshwater temperatures. Peter Moyle, a biologist at the University of California Davis, has been more concerned with the freshwater fish that make their homes in, or migrate to, California’s rivers and lakes. He and colleagues report in the journal PLOS One – the Public Library of Science – that if current climate trends continue, then 82 per cent of California’s native fish could be extinct, and their native homes colonized by invasive species. The scientists looked at 121 native species and found that four fifths of them were likely to be driven to extinction or at least to very low numbers. These include prized sporting fish such as the Klamath River summer steelhead and other trout, the Central Valley Chinook salmon, the Central Coast coho salmon and many others that depend on cold water. “These fish are part of the endemic flora and fauna that makes California such a special place,” said Prof Moyle. “As we lose these fishes, we lose their environments and are much poorer for it.” – Climate News Network        

For immediate release On both sides of the Atlantic scientists studying lakes have discovered they are warming – and this is bad news both for water quality and the fish. London, 14 June – The Alpine lakes of Austria are warming up. By 2050, their surface waters could be up to 3°C warmer, according to new research in the journal Hydrobiologia. Martin Dokulil of the Institute for Limnology at the University of Innsbruck studied data from nine lakes larger than 10km2. The largest, Bodensee or Lake Constance, touches Austria’s border with Germany and Switzerland to the west; 800 kms to the east, Neusiedler See borders Germany and Hungary. The nine lakes range from 254 to 1.8 metres maximum depth and they are vital to Austria’s tourist industry: they play powerful roles in the Alpine ecosystem and they are of course reservoirs of water. But the Alpine valleys are warming: between 1980 and 1999 the region warmed at three times the global average and by 2050 the median temperatures for the region could have risen by 3.5°C. The challenge has been to anticipate the impact of global warming on the lakes. “The predicted changes in surface water temperatures will affect the thermal characteristics of the lakes,” says Dr Dokulil. “Warmer water temperatures could lead to enhanced nutrient loads and affect water quality by promoting algal blooms and impairing the biological functions of aquatic organisms. “Significant increases in summer temperatures will affect the carbon cycling in the lakes, with potential consequences on atmospheric carbon dioxide levels and the Earth’s climate.”  Next, the fish The Austrian research so far is concerned only with freshwater temperatures. Peter Moyle, a biologist at the University of California Davis, has been more concerned with the freshwater fish that make their homes in, or migrate to, California’s rivers and lakes. He and colleagues report in the journal PLOS One – the Public Library of Science – that if current climate trends continue, then 82 per cent of California’s native fish could be extinct, and their native homes colonized by invasive species. The scientists looked at 121 native species and found that four fifths of them were likely to be driven to extinction or at least to very low numbers. These include prized sporting fish such as the Klamath River summer steelhead and other trout, the Central Valley Chinook salmon, the Central Coast coho salmon and many others that depend on cold water. “These fish are part of the endemic flora and fauna that makes California such a special place,” said Prof Moyle. “As we lose these fishes, we lose their environments and are much poorer for it.” – Climate News Network        

Warming climate can drive algal blooms

FOR IMMEDIATE RELEASE  A warming climate is expected to encourage the development of suitable conditions for more algal blooms to form on one of the Great Lakes of the North American continent. LONDON, 3 April – Devastating algal blooms on one of the Great Lakes on the Canada-US border could become a much more frequent event, according to scientists from the Carnegie Institution and the University of Michigan. They report in the Proceedings of the National Academy of Sciences that conditions in 2011 were just right for a perfect storm of algal growth that turned Lake Erie an ugly blue-green, killed fish, fouled harbours, clogged marine engines, created oxygen-free dead zones and released unwholesome quantities of a liver toxin poisonous to mammals. And although the bloom was a consequence of the unhappy combination of agricultural management and unusual weather conditions, global warming could make such episodes more frequent. In 2010 conditions were fine for both the planting and harvesting of corn, wheat and soya in Ohio’s Maumee River basin. The Maumee drains into western Lake Erie. The following spring, record rains fell in May, dumping 75% more water than the average for that month, and washing large quantities of phosphorus fertiliser applied to the soil that spring down the water course and into the lake. The spring storms were followed by a fine summer, with calm winds and warm water temperatures. These conditions were ideal for the explosive growth of the toxic blue-green algae Microcystis, and the poison it produced was, at its highest, 224 times the World Health Organisation guidelines for safe levels.

Record-breaking spread

  The bloom began in mid-July over a 600 square-kilometre patch of water and then – because the conditions were perfect –  began to spread. Because there were no currents, the potential nutrients stayed in the lake and because temperatures were mellow the algal bloom went on spreading. At its peak in October, a thick scum of the bloom covered 5,000 square kilometres. Blooms had happened before: this one was seven times greater than the average of the last nine years, and more than three times bigger than the last record bloom in 2008. The researchers took a long cool look at past and projected future climates, and came to a conclusion that – once again because of the continued release of greenhouse gases and consequent planetary warming – there would be an increase in “extreme spring precipitation events”. Stronger storms could be twice as frequent. Sluggish circulation of the lake water is also expected in future, because wind speeds across the US on average seem to be decreasing. So the conditions for devastating blooms will continue. “Lacking the implementation of a scientifically guided management plan designed to mitigate these impacts”, the paper’s 29 authors conclude, “we can therefore expect this bloom to indeed be a harbinger of future blooms in Lake Erie.” – Climate News Network

FOR IMMEDIATE RELEASE  A warming climate is expected to encourage the development of suitable conditions for more algal blooms to form on one of the Great Lakes of the North American continent. LONDON, 3 April – Devastating algal blooms on one of the Great Lakes on the Canada-US border could become a much more frequent event, according to scientists from the Carnegie Institution and the University of Michigan. They report in the Proceedings of the National Academy of Sciences that conditions in 2011 were just right for a perfect storm of algal growth that turned Lake Erie an ugly blue-green, killed fish, fouled harbours, clogged marine engines, created oxygen-free dead zones and released unwholesome quantities of a liver toxin poisonous to mammals. And although the bloom was a consequence of the unhappy combination of agricultural management and unusual weather conditions, global warming could make such episodes more frequent. In 2010 conditions were fine for both the planting and harvesting of corn, wheat and soya in Ohio’s Maumee River basin. The Maumee drains into western Lake Erie. The following spring, record rains fell in May, dumping 75% more water than the average for that month, and washing large quantities of phosphorus fertiliser applied to the soil that spring down the water course and into the lake. The spring storms were followed by a fine summer, with calm winds and warm water temperatures. These conditions were ideal for the explosive growth of the toxic blue-green algae Microcystis, and the poison it produced was, at its highest, 224 times the World Health Organisation guidelines for safe levels.

Record-breaking spread

  The bloom began in mid-July over a 600 square-kilometre patch of water and then – because the conditions were perfect –  began to spread. Because there were no currents, the potential nutrients stayed in the lake and because temperatures were mellow the algal bloom went on spreading. At its peak in October, a thick scum of the bloom covered 5,000 square kilometres. Blooms had happened before: this one was seven times greater than the average of the last nine years, and more than three times bigger than the last record bloom in 2008. The researchers took a long cool look at past and projected future climates, and came to a conclusion that – once again because of the continued release of greenhouse gases and consequent planetary warming – there would be an increase in “extreme spring precipitation events”. Stronger storms could be twice as frequent. Sluggish circulation of the lake water is also expected in future, because wind speeds across the US on average seem to be decreasing. So the conditions for devastating blooms will continue. “Lacking the implementation of a scientifically guided management plan designed to mitigate these impacts”, the paper’s 29 authors conclude, “we can therefore expect this bloom to indeed be a harbinger of future blooms in Lake Erie.” – Climate News Network