Ecological Consequences of Freshwater Acidification

[bligh8]

Ecological Consequences of Freshwater Acidification

Rising pCO2 in Freshwater Ecosystems Has the Potential to Negatively Affect Predator-Induced Defenses in Daphnia



Highlights
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35-year monitoring data showed steady pCO2 increase and pH decrease in four reservoirs
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Freshwater acidification affects inducible defenses in the keystone speciesDaphnia
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pCO2 hampers neuronal kairomone transmission, preventing full defense expression
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Increased pCO2, rather than reduced pH, impairs predator perception in Daphnia

“pCO2-dependent freshwater acidification has been found to impair physiology of larval development in pink salmon with CO2 dose-dependent reductions in growth, yolk-to-tissue conversion, and maximal O2-uptake capacity. Moreover, changes of behavioral responses showing significant alterations in olfactory abilities with mal-adaptive anti-predator strategies and increased anxiety were observed [12, 27, 28,29]. In this context, field experiments have shown that juvenile Atlantic salmon (Salamo salar) experiences greater predation rates [30]. Also, invertebrate taxa have recently been found to be susceptible to elevated pCO2, which affected valve movement in three North American freshwater mussels [31].”


http://www.cell.com/current-biology/fulltext/S0960-9822(17)31655-X

[sidd]

I posted a paper in another thread that shows increasing alkalinization in US freshwater, which seems to overwhelm the trend toward acidification from increasing atmospheric CO2

"Although individual trends can vary in strength, changes in salinization and alkalinization have affected 37% and 90%, respectively, of the drainage area of the contiguous United States over the past century. Across 232 United States Geological Survey (USGS) monitoring sites, 66% of stream and river sites showed a statistical increase in pH, which often began decades before acid rain regulations. The syndrome is most prominent in the densely populated eastern and midwestern United States, where salinity and alkalinity have increased most rapidly.The syndrome is caused by salt pollution (e.g., road deicers, irrigation runoff, sewage, potash), accelerated weathering and soil cation exchange, mining and resource extraction, and the presence of easily weathered minerals used in agriculture (lime) and urbanization (concrete). Increasing salts with strong bases and carbonates elevate acid neutralizing capacity and pH, and increasing sodium from salt pollution eventually displaces base cations on soil exchange sites, which further increases pH and alkalinization.  "

open access:     doi: 10.1073/pnas.1711234115

sidd

[Daniel B.]

Maybe these two effects can combine together and cancel one another.

[sidd]

The study i posted looked at a large number of stream and river sites, flowing water, in the USA . Bligh8 posted an article looking at four reservoirs in Germany. It would be interesting to see a comparable study for reservoirs in the USA.

In fact I have one in mind in Ohio, built as part of floodcontrol in the Ohio Valley in the 30's by the CCC. I know of one monitoring site at least around there, should talk to them. There are atleast two I know of in PA of that vintage. Some of the lakes in Minnesota would be nice too.

sidd