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The primary objective of this study was to determine the composition of Armillaria species in northeastern North American Pinus- and Tsuga-dominated forests. This was accomplished by sampling 32 plots at eight sites within pitch pine (Pinus rigida Mill.), eastern white pine (Pinus strobus L.), eastern white pine - mixed oak, and eastern hemlock (Tsuga can-adensis (L.) Carr.) forests. In total, 320 isolates were collected from 19 host tree species, with 207 of 320 (65%) of all isolations coming from Pinus and Tsuga. Armillaria solidipes Peck was the most abundant species, making up 188 of 320 (59%) of all isolations, which included 39 isolations from hardwoods. Meanwhile, Armillaria mellea (Vahl) P. Kumm. was col-lected a total of 27 times from eastern white and pitch pine. These two Armillaria species co-occurred at five of the eight sites sampled. Chi-square analyses showed that incidence of Armillaria species were significantly different by forest type. Pitch pine forests had a higher incidence of A. solidipes (p < 0.001), eastern white pine forests had a higher incidence of A. mellea (p = 0.001), and eastern hemlock forests had a higher incidence of Armillaria gallica Marxm. & Romagn. (p = 0.002) compared with expected values. The distribution of A. solidipes varied significantly by soil drainage and soil type, with a higher incidence on excessively drained (p < 0.001) and loamy sand (p < 0.001) soils. Resume: Cette etude visait surtout determiner la composition en especes d'Armillaria dans les forets dominees par Pinus et Tsuga dans le nord-est de l'Amerique du Nord. Elle a ete realisee en echantillonnant 32 places echantillons dans huit stations situees dans des forets de pin rigide (Pinus rigida Mill.), de pin blanc (Pinus strobus L.), de pin blanc et d'un melange de chenes, ainsi que de pruche du Canada (Tsuga canadensis (L.) Carr.). Au total, 320 isolats ont ete collectes sur 19 espe-ces d'arbres hotes et 207 de 320 (65 %) de tous les isolats provenaient de Pinus et de Tsuga. Armillaria solidipes Peck etait l'espece la plus abondante, constituant 188 de 320 (59 %) de tous les isolats, qui incluaient 39 isolats provenant de feuillus. Pendant ce temps, Armillaria mellea (Vahl) P. Kumm. a ete isole 27 fois au total chez le pin blanc et le pin rigide. Ces deux especes d'Armillaria se cotoyaient dans cinq des huit stations echantillonnees. Des analyses du chi carre ont montre que l'incidence des especes d'Armillaria etait significativement differente selon le type de foret. Il y avait une plus forte incidence d'A. solidipes (p < 0,001) dans les forets de pin rigide, d'A. mellea (p = 0,001) dans les forets de pin blanc et d'Ar-millaria gallica Marxm. & Romagn. (p = 0,002) dans les forets de pruche comparativement aux valeurs esperees. La distribution d'A. solidipes differait de fa?on significative en fonction du drainage et du type de sol; l'incidence de cette espece etait plus forte sur les sols excessivement draines (p < 0,001) et les sols de sable loameux (p < 0,001). [Traduit par la Redaction], Introduction Armillaria root disease, caused by Armillaria species ((Fr.: Fr.) Staude), is widely regarded as one of the most important diseases of coniferous trees throughout the world (Hansen and Lewis [...]

The highway deicing agent groundwater plume from an infiltration basin in the Plymouth-Carver Aquifer near State Route 25 in southeastern Massachusetts is modeled and measured in order to assess the impact of the basin on groundwater transport processes. The advective transport model superimposes the existing steady models of axisymmetric basin hydraulics of Zlotnik and Ledder in 1992 and the two-dimensional ambient flow of Gelhar and Wilson in 1974. The basin component incorporates a surface source of finite-radius into a Hankel transform model for unconfined aquifers, whereas the ambient component varies linearly in the horizontal and vertical directions. Contaminant streamlines describe the resulting groundwater plume, and highway deicing agent constituents provide useful tracers. A simple vertical dispersion model quantifies the spread of contaminants across the bottom of the plume. Deicing agent constituent data calibrate a 17 m basin radius, a 45 m plume width, a bottom streamline 6-10 m below the water table, and a vertical dispersivity of 34 cm. The latter value is comparable to the amplitude of vertical excursions caused by storm scale fluctuations of hydraulic head, as measured by Ostendorf et al. in 2007. Infiltration basins alter ambient advection by displacing streamlines downward and augment vertical mixing by imposing aperiodic vertical fluctuations on the ambient flow field. CE Database subject headings: Stormwater management; Deicing; Runoff; Infiltration; Massachusetts; Highways and roads.

The author examines the health consequences of Massachusetts' contaminated drinking water. Topics include cancer, tetrachoroethylene exposure, and health risk factors.

Fulvic acid fraction of dissolved organic carbon and synthetic organic compounds was analyzed from copper contaminated stream water samples collected for seven sampling stations in Massachusetts. Competitive binding by ethylenediaminetetraacetic acid affected the binding of Cu with fulvic acids in the stream water samples. Furthermore, the toxicity of Cu was reduced by the presence of organic ligands due to ligand binding.

Bioassay-directed fractionation procedures were employed to study the main human cell mutagens in organic extracts of sediments from Wedge Pond in eastern Massachusetts. The samples' mutagenicity, which have been proved to be mutagenic in human cells, were resolved to two subfractions which contain polycyclic aromatic hydrocarbons. The latter's presence was measured by liquid chromatographic separation with ultraviolet-vis spectrometic sensing.

In October 1969 George Hampson and Howard Sanders (Woods Hole Oceanographic Institution, WHOI) described a 'Local Oil Spill' in Oceanus. The spill had occurred a month before when the barge [...]

Issues relating to the distribution of ixodid ticks are discussed. A study is conducted on vegetation in north-central Massachusetts to evaluate the ixodid tick population.

Sanitary sewer systems collect and carry wastewater from homes, businesses, and industrial sites to treatment facilities. An influx of water during maintenance or rainstorms can overwhelm sewers, sending raw wastewater [...]

Loss of eelgrass (Zostera marina) habitat from temperate estuaries worldwide often coincides with increased macroalgal accumulations resulting from increased delivery of anthropogenic nitrogen. We conducted macroalgal enclosure/exclosure experiments during summer 1998 within eelgrass populations in two estuaries of Waquoit Bay, Massachusetts, USA, to evaluate how increased macroalgal biomass affects density, recruitment, growth rate, and production of eelgrass. One estuary featured a low nitrogen loading rate and sustained a relatively pristine eelgrass population with a 2 cm high macroalgal canopy. The other estuary had a sixfold higher nitrogen loading rate and a declining eelgrass population with a 9 cm high macroalgal canopy. Experimental units were 1 x 1 m plots of eelgrass fenced within 50 cm high plastic mesh that excluded or included macroalgae at canopy heights ranging from 0 to 25 cm. In both estuaries, rates of eelgrass loss increased, largely a result of decreased recruitment, and growth rates decreased (due to decreased rates of leaf appearance) with increasing macroalgal canopy height. Aboveground summer production in both estuaries decreased exponentially as macroalgal canopy heights increased. We conclude that macroalgal cover is a proximate cause for loss of eelgrass in the higher N estuary since, upon removal of macroalgae, we observed an increase in shoot density, a 55% increase in summer growth, and a 500% increase in summer aboveground net production. Based on summer growth data and density of shoots in our experimental plots the following spring, we suggest that the negative impacts of macroalgal canopies persist, but also that eelgrass recovery upon removal of macroalgae may be possible. To identify the mechanisms by which macroalgae potentially inhibit eelgrass production, we measured changes in nutrient and oxygen concentrations resulting from macroalgal canopies and estimated the relative importance of summer standing stocks of phytoplankton, epiphytes, and macroalgae to potential shading of eelgrass in both estuaries. We document both (1) unfavorable biogeochemical conditions (lowered redox conditions and potentially toxic concentrations of [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]) imposed by the presence of macroalgal canopies and (2) potential light limitation of eelgrass by standing stocks of producers in the higher N estuary, with estimates of light reduction via macroalgae numerically more important than light sequestration by phytoplankton and epiphytes for newly recruiting shoots. Increased macroalgal biomass associated with increased nitrogen loading to estuaries can lead to eelgrass disappearance, and we identify an approximate 9-12-cm critical macroalgal canopy height at which eelgrass declines. Key words: ammonium toxicity; Cladophora vagabunda; eelgrass; epiphyte; estuary; Gracilaria tikvahiae; light; macroalgae; nitrogen; nutrient; phytoplankton; Zostera marina.