The influence of organic acidity on the acid-base chemistry of surface waters in Maine, USA

✍ Scribed by J. S. Kahl; S. A. Norton; R. K. MacRae; T. A. Haines; R. B. Davis

• Publisher: Springer Netherlands
• Year: 1989
• Tongue: English
• Weight: 740 KB
• Volume: 46
• Category: Article
• ISSN: 0049-6979
• DOI: 10.1007/bf00192859

✦ Synopsis

Results from surveys of Iow-ANC lakes (high elevation, and seepage lakes), and of surface waters in dystrophic, acidic bogs, indicate that acidic precipitation and organic acidity are each generally necessary, but not solely sufficient, for chronicallyacidic status in Maine lakes. Acidic, low DOC (ANC < 0; DOC < 5 mg L -i) lakes of all hydrologic types are acidic due largely to acidic deposition; high DOC (DOC > 30 mg L -l) acidic seepage lakes are acidic due largely to organic acidity, and high DOC drainage lakes are acidic due to a combination of both factors.

No low DOC drainage lakes are known with pH less than about 5.0, suggesting that organic acidity is necessary to depress lake pH values to below 5 in Maine at current deposition loadings.

The dominant anion of low DOC, acidic waters is sulfate.

Acidic waters with intermediate concentrations of DOC (5 to 30 mg L-l), may be dominated by SO 4 andlor organic acidity.

Seepage-input lakes were the only group to include both organically-dominated (37% of the acidic lakes) and SO 4dominated members (63% of the acidic lakes). High DOC systems are typically low pH bogs, and are all organic acid-dominated.