Experimental Acidification of a Stream in the Hubbard Brook Experimental Forest, New Hampshire

摘要: Incident precipitation in the northeastern United States averages about pH 4 as a result of increased pollution from sulfuric and nitric acids. To determine effect this acidity on ecology aquatic ecosystems, dilute concentrations acid were added to Norris Brook, stream Hubbard Brook Experimental Forest, West Thornton, New Hampshire, USA. The was maintained at April September 1977. With water Al, Ca, Mg, K, probably Mn, Fe, Cd elevated; no change dissolved organic carbon (DOC), Na, NO,, NH4, Ni, Pb, Cu, or Zn occurred lower pH. Emergence adult mayflies (Ephemeroptera), some stoneflies (Plecoptera), true flies (Diptera) decreased Larger numbers immature inver- tebrates collector, scraper, predator functional groups found drift samples experimental area during 1st wk after addition. After total organisms drifting similar values obtained reference area. collectors invertebrate density benthos treatment Periphyton biomass low pH, but hyphomycete fungal densities decreased. A basidiomycete fungus relative section. trout showed morphological signs stress Stream acidification species di- versity, representation community dominants. complexity food web.