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The gypsy moth (Lymantria dispar L.), a major defoliator of hardwood forests in the eastern U.S., has a highly alkaline midgut pH. We hypothesized that the high pH would cause high rates of ammonia (NH) volatilization as larvae consumed foliage, leading to potentially large losses of N from the ecosystem to the atmosphere during gypsy moth outbreaks. We measured NH emission during the consumption of oak foliage by larvae in the laboratory. Surprisingly, we found very low amounts of NH release of about 0.1% of the N consumed in foliage. We speculate that digestive mechanisms may limit NH production in the midgut, and that the acidic environment of the hindgut traps most of the small amount of NH that is produced, effectively preventing a potentially very large N loss from both larvae and ecosystem. The estimated rate of NH emission from a defoliated forest is small compared to other inputs and outputs of N from the ecosystem, but could potentially enhance the neutralization of atmospheric acidity during the defoliation period.

Crankley Point Sewage Treatment Works, Newark, England treats both municipal and industrial wastes. The introduction of new discharge consents establishes an ammonia standard for the first time. Particular industrial wastes pose constraints to comply with this standard, causing highly varied ammonia loads to pass through the works.Severn Trent Services evaluated the TETRA submerged aerated filter (SAF) and deep-bed filter (DBF) technologies to establish their ability to perform under the following conditions:• Naturally occurring variations in ammonia • Sudden and prolonged spikes in ammonia • Washout from the activated sludge plant.The SAF and DBF technologies coped well under normal diurnal and weekly conditions and responded quickly to sudden high increases in ammonia, maintaining effluent levels for periods of 24 hours and returning to normal levels once shock load conditions ceased.As a result of these trials, Crankley Point Sewage Treatment Works is being extended to incorporate the TETRA SAF and DBF technologies.