Blue-Green Algae Blooms

Lake Erie algae

Warmer summer temperatures and ongoing phosphorus loading from agricultural nutrient runoff has led to a disruptive frequency of blue-green algae blooms in freshwater lakes.

This summer a cyanobacterial bloom in Lake Erie left 400,000 people without drinking water for two days.

America the Beautiful

Oh Beautiful for smoggy skies, insecticided grain,
For strip-mined mountain's majesty above the asphalt plain.
America, America, man sheds his waste on thee,
And hides the pines with billboard signs, from sea to oily sea.
― George Carlin

Water near Toledo intake
Photograph: Haraz N. Ghanbari/AP

Toxic Algae

The dominant organisms of the summer season algal blooms occurring in Lake Erie are microcystins.

Microcystis causes skin rashes. If ingested it causes vomiting and liver damage. Microcystis can be fatal if ingested by dogs or other animals.

Freshwater algae blooms create adverse conditions because they:

• deplete the dissolved oxygen content of water;
• contaminate drinking water making it impotable;
• threaten commercial and recreational fisheries; and
• degrade recreational swimming and fishing.

Algae bloom in the west end of Lake Erie
NASA’s Aqua satellite, 8/1/14.

We assume that everything's becoming more efficient, and in an immediate sense that's true; our lives are better in many ways. But that improvement has been gained through a massively inefficient use of natural resources.
― Paul Hawken

REFERENCES

• Aqua Project Science, NASA.
• Farming practices and climate change at root of Toledo water pollution, by Suzanne Goldenberg, The Guardian, 3 August 2014.
• Record-setting algal bloom in Lake Erie caused by agricultural and meteorological trends consistent with expected future conditions, Michalak, A.M., et al., Proceedings of the National Academy of Sciences, Vol. 110 (16), 6448-6452, 2013.

Atmospheric Oxygen

Blue-green algae bloom

Photosynthesis on land (~ 55%) and photosynthesis in the ocean (~ 45%) account for nearly 100% of Earth's atmospheric oxygen.

A fraction comes from the breakup of water (photolysis) from ultraviolet radiation.

"The oxygen in today's atmosphere is almost entirely the result of photosynthetic living, which had its start with the appearance of blue-green algae among the microorganisms."
― Lewis Thomas

The annual gain of atmospheric oxygen is shown below:

Photosynthesis (land) Photosynthesis (ocean) Photolysis of N2O Photolysis of H2O	16,500 13,500 1.3 0.03
Total	~ 30,000
units 1010 kg O2 per year

Plants, algae, and cyanobacteria perform photosynthesis which maintains atmospheric oxygen and supplies all of the organic compounds and most of the energy necessary to sustain life in Earth's biosphere.

"One hundred and fifty years ago, the monster began, this country had become a place of industry. Factories grew on the landscape like weeds. Trees fell, fields were up-ended, rivers blackened. The sky choked on smoke and ash, and the people did, too, spending their days coughing and itching, their eyes turned forever toward the ground. Villages grew into town, towns into cities. And people began to live on the earth rather than within it."
― Patrick Ness, A Monster Calls

An LED screen in Tiananmen Square showing the rising sun
in a tourism advertisement for China’s Shandong province
while Beijing is shrouded in smog. 16 January 2014.

REFERENCES

• Oxygen Cycle, Wikipedia.
• China starts televising the sunrise on giant TV screens because Beijing is so clouded in smog, by James Nye, Daily Mail, 17 January 2014.
• Late Night Thoughts on Listening to Mahler's Ninth Symphony, Lewis Thomas, 1995.
• Photosynthesis, Wikipedia.