Experimental acidification of two biogeochemically-distinct neotropical streams: Buffering mechanisms and macroinvertebrate drift

► We experimentally acidified a poorly and a well buffered stream in Costa Rica. ► The well buffered stream neutralized 745 µeq/L (96% of the acid added). ► The poorly buffered stream only neutralized 27.4 µeq/L (40% of the acid added). ► Protonation of HCO3- was the most important buffering mechanism in both streams. ► Macroinvertebrate drift increased in both streams in response to acidification.