Blooms accelerates climate change, say climatologists

The acidity of the World Ocean is growing faster and faster because of the rapid "bloom" of water, which can cause rapid climate change, climate scientists write in a paper published in the journal Nature Geoscience.

Cause algal blooms of blue-green algae, or cyanobacteria that live in freshwater lakes and reservoirs, as well as in sea water.

When the "explosive" growth of cyanobacteria in the water having large spots that may threaten the health of people and animals and to inflict economic damage to tourism destinations.

It is believed that climate change and, in particular, the increase in water temperature will promote "bloom", but all the climatic effects of these "spots" are still unknown.

Cai Wei-chun (Wei-Jun Cai) from the University of Georgia (USA) and his colleagues found that the widespread algal blooms will not only saturate the world's oceans with carbon dioxide and acidification, but also to the increased vulnerability of surface waters to further increase the acidity .

Cai and his colleagues came to this conclusion by tracing the evolution of cyanobacteria on the coasts of the United States and China. The two largest rivers in the world — the Mississippi and Yangtze — are dumped on the shallow water Gulf of Mexico and the East China Sea, a huge amount of nitrogenous fertilizers, which feed on the blue-green algae. For the second half of the 20th century nitrate emissions — the main component of the "seasoning" — have tripled in the United States and four times — in China.

As part of their work, scientists repeatedly took water samples from different locations in the Gulf of Mexico and the East China Sea throughout the growing season. Climate scientists compare them to the amount of carbon dioxide, oxygen and biomass.

How do I find the authors, the increase of concentration CO2, falling oxygen levels and acidification started already in the early spring, and this trend continued throughout the summer and early fall. The relationship between the fall of the share of oxygen in sea water and decreasing pH indicates that the oxygen consumed by oxidation of organic remains, which increased due to algal blooms.

Climatologists then compared the increase in CO2 in the atmosphere and in the waters to the change of acidity. It is believed that the acidity of the water in the oceans depends largely on the amount of carbon dioxide absorbed by its water. Thus, the increase in the concentration of atmospheric carbon dioxide must be accompanied by a similar increase in the strength of acidity.

Estimated Kai and his colleagues, these numbers do not add up — the real acidity increased by additional 0.05 pH units than expected. This can be explained by the ability of water to absorb the additional portions of carbon dioxide decreases as the concentration.

Thus, further changes in the concentration of CO2 could lead to even greater fluctuations in pH, the effects of which can be quite noticeable, not only marine life, but for the entire planet.


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