It has been an unusually rainy spring here in Big Sur. We received 1.86″ of rain in May and have just had another full on winter storm here in the first week of June. I’ll be summarizing the 2010-2011 rain season data once it is clear the rainy season had ended.
The rains in May were notably acidic. There were five measurable rainfall events with pH values ranging between 4.46 to 4.63. The table below shows all the results for May 2011.
Early spring is a time when I would expect lower pH values if the source of acidity is primarily from biogenic sulfur emissions of ocean phytoplankton. Early spring is when terrestrial runoff is high, providing nutrients that fuel the phytoplankton blooms.
Biogenic acid rain is a real phenomena that for whatever reasons has been overlooked in the climate and earth system sciences. When the true extent of biogenic acid rain is finally recognized I suspect we will have to rewrite our theories on rock weathering processes, climate change, forest decline, and ecosystem succession.