Early season rainfall pH measurements in Big Sur

19 10 2009

Here is some news for those of you interested in following the story of acid rain in Big Sur. The first rains have arrived here in Big Sur in a big way, 8.45″ of rain fell between Oct. 12 and 14. The pH readings on the first 3 inches of rain averaged 5.41, the highest value (lowest acidity) yet recorded in over three years of measurements.

Another small storm brought some rain today (Oct. 19) which totaled just 0.14″, with a pH value of 4.79. This value is more in line with readings from the previous three years and represents a significant drop (increase in acidity) compared to the heavy rains last week.

What do you suppose is going on?

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10 responses

28 10 2009
alberi

What’s going on is what is going on worldwide. Wet and Dry deposition from acidic sources are increasing at an alarming rate. This is apparent by the recent revelation that oceans are acidifying which is harming the coral reefs. Acidification harms forest trees by leaching calcium and magnesium from leaves and suppressing their immune systems. This immune system damage makes trees more susceptible to all types of disease and insect infestations.

28 10 2009
Lee Klinger

The Mercury News reported that the Oct.12-13 storm was the largest October storm to hit Northern California in the past 47 years. Seems I heard that the weather system was a remnant of a typhoon somewhere in the North Pacific, but am not certain this is the case.

28 10 2009
Lee Klinger

alberi – I agree with you that environmental acidification is linked to mineral (especially calcium) deficiencies and enhanced susceptibility of trees to pests and diseases. It does seem that acidification is happening in many forests of the world, although I would not say acidification is occurring worldwide. As you can see in my earlier post on acid rain in Big Sur, the pH trends vary from region to region. Precipitation pH appears to be getting less acidic in So Cal and more acidic in the Olympic Peninsula of WA.

Also, the sources of acidity, be they anthropogenic or biogenic, are still not well known. The acidification of the oceans, while important, probably has little to do with the sources of acidity we are seeing in the precipitation falling on Big Sur and other remote areas.

I’m still curious why Big Sur saw such a large swing in rainfall pH with the first two events this season. Was there anything about the buildup of the large storm that could explain its unusually high pH?

3 11 2009
Alberi

It’s the buildup of anthopogenic sulfur and nitrogen from all the pollution produced from auto exhaust and coal fired plants in China etc…. Every summer, there is a buildup of NOx emissions in California all summer and then the first rains bring this pollution back to us in the form of acid rain. Check out the CA air resources board research , there is a wealth of data and research that documents the presence of acid rain and acid fog in California.

3 11 2009
Lee Klinger

Sulfur and nitrogen pollution from China is a possible contributor to the rainfall acidity in coastal California. But I’m not aware of any study that shows this conclusively. The CA air resources board research only examines regional sources of pollution, not China. But in Big Sur and other Pacific coast locations, the rain-bearing air masses are coming in from the west, so CA pollution is not a likely source. Also, the first rains were unusually high in pH (less acidic), so your idea that “there is a buildup of NOx emissions in California all summer and then the first rains bring this pollution back to us in the form of acid rain” is not supported by my measurements in Big Sur.

There are lots of questions that need to be answered before anyone can say with certainty anything about the sources of acidity in the Big Sur rain. What about the role of all the dimethyl sulfide, carbonyl sulfide, carbon disulfide, and countless other gaseous compounds emitted by ocean organisms? What are the acidic ions in the coastal rains and what are the cation/anion balances? Do back-trajectory analyses of air masses indicate China as a source region? Do the sulfur/carbon isotopes in the rain indicate a fossil fuel/combustion source?

Regardless of the source, you are right to emphasize the importance of the problem, that the rainfall here on the central coast of California is acidic and it may stay this way for some time. That information is very relevant and informs the way I manage the land and trees.

5 11 2009
Alberi

So is it not time for a comprehensive study demonstrating the link between ecosystem acidification and forest tree diseases like sudden oak death and here in the east beech decline, which is also a phytophthora infection. It is also interesting to note that both california live oaks affected by SOD and Beech trees here in the east are in the same family Fagaceae. This study would then basically demonstrate the fungal infection are much like the ambrosia beetles- secondary .

5 11 2009
Lee Klinger

Alberi – I’m all for such a study, but in no way should a study be done with the intent to demonstrate anything. Just design a proper study, make sure the data are analyzed in a double blind fashion to avoid bias, and report the results.

20 12 2009
witsendnj

Lee Klinger, I’m very excited to have found your blog via your comment at the Oil Drum.

Here’s a link to a study about pollution from China impacting California:

http://www.sciencedaily.com/videos/2008/0710-overseas_pollution_hitting_the_us.htm

A question for you: Are trees other than oaks in decline? Where I live, EVERY kind of tree is in decline, as is anything that needs to photosynthesize and produce chlorophyll.

20 12 2009
Lee Klinger

Thank you for the comment and link. While pollution from China is probably contributing to the acidity, it does not appear to be the dominant source. As the study in your link indicates air from China comprises only 12% of the pollution in the western US. The remainder in places like Big Sur is unknown. I suspect, however, that sulfur emission from ocean phytoplankton are playing a significant role.

Yes, many kinds of trees are dying here in California. But the degree of decline varies from region to region. The decline affects mainly older trees, while young trees tend to be flourishing. Total leafy biomass has been shown to be increasing. In coastal CA the decline problem IMO has more to do with fire suppression than with air quality.

20 12 2009
witsendnj

Hi Lee! Have you considered that ethanol emissions, which have recently increased due to EPA mandates it be added to gasoline, are considerably more toxic to humans and plants? According to a Stanford study http://www.sciencedaily.com/releases/2009/12/091214101408.htm

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